AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 346 AM MST TUE FEB 12 2008 .SHORT TERM... (TODAY AND TONIGHT) ...MAIN SHORT TERM CONCERN INCLUDES TEMPERATURES AND WINDS... CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATED STRONG NORTH TO NORTHWEST FLOW ALOFT AS 120+ KT NORTH/SOUTH JET CORE TRANSLATES ACROSS THE ROCKIES. TODAY AND TONIGHT...FLOW ALOFT MODERATES AND BECOMES MORE WEST TO NORTHWEST AS JET CORE ACROSS THE ROCKIES TRANSLATES EAST INTO THE UPPER MIDWEST AND NORTHERN HIGH PLAINS THROUGH TONIGHT. TEMPERATURES ALOFT MODERATE WITH HEIGHTS BUILDING FROM WEST TO EAST ACROSS THE STATE AND EXPECT THE GUSTY NORTHWEST WINDS ACROSS THE HIGHER TERRAIN TO SLOWLY DIMINISH THROUGH THE DAY. MODELS KEEPING SHALLOW MOISTURE LAYER IN PLACE ACROSS THE NORTHERN AND CENTRAL MTS WITH DECENT OROGRAPHIC FLOW...THOUGH WITH POOR LAPSE RATES NOT EXPECTING MUCH MORE THAN A FEW FLURRIES. SOUNDINGS INDICATING GUSTY NORTHWEST WINDS OF 15 TO 25 MPH MIXING DOWN ACROSS THE EASTERN PLAINS LATE THIS MORNING HELPING TO WARM TEMPS INTO THE AFTERNOON...THOUGH WITH BOUTS OF CLOUDS ASSOCIATED WITH PASSING JET CORE...HAVE KEPT STAYED CLOSE TO MAV GUIDANCE FOR TEMPS...SAVE THE SAN LUIS VALLEY WHERE STRONG INVERSIONS LOOK TO PERSIST. .LONG TERM... (WEDNESDAY THROUGH MONDAY) ...WARM AND BREEZY/WINDY BEFORE THE STORM ON WEDNESDAY... ...POTENTIAL HIGH IMPACT WINTER WEATHER WEDNESDAY NIGHT-THURSDAY EVENING... WEDNESDAY...GENERALLY SHORT RANGE MODELS IN FAIR AGREEMENT WITH THE SYNOPTIC SCALE PATTERN WITH RELATIVELY VIGOROUS WEST-SOUTHWEST FLOW OVER MUCH OF CO AHEAD OF THE DIGGING WEATHER SYSTEM OVER THE GREAT BASIN. SHOULD SEE A RELATIVELY MILD/WARM DAY...BUT AT THE EXPENSE OF BREEZY/WINDY CONDITIONS. SURFACE CYCLOGENESIS IS FORECAST ACROSS NORTHEAST CO WITH LEE SIDE TROUGHING TRAILING SOUTHWARD ACROSS THE HIGH CO PLAINS. 45-65KT AT H7 ALONG WITH MODERATELY UNSTABLE MIDLEVEL LAPSE RATES COULD PROMOTE BREEZY/WINDY CONDITIONS ACROSS MUCH OF SOUTHERN CO. THE ONLY CHALLENGE WOULD BE A BKN-OVC CS/CI MOUNTAIN WAVE CLOUD ALONG THE CO FRONT RANGE THAT COULD TEMPER THE TEMPERATURES IF THE WINDS DON`T PICK UP. IF BREEZY/WINDY CONDITIONS DEVELOP IN THE SAN LUIS VALLEY...THEN TEMPERATURES COULD GET INTO THE 30S APPROACHING 40F. CRITICAL FIRE WEATHER CONCERNS COULD BE INCREASING ACROSS THE FAR SOUTHEASTERN CO PLAINS...BUT MOST AREAS DID RECEIVE SNOWFALL LAST WEEK IN SOME CASES AROUND 12 INCHES. THE BLM FIRE WEATHER FUELS PAGE IS SIGNIFICANTLY OLD ON THE INTERNET...SO THAT IS NO HELP. DAYTIME MINIMUM HUMIDITY VALUES WILL DROP BELOW 20%...BUT WIND SPEEDS MIGHT NOT REACH CRITICAL LEVELS. WILL HOLD OFF ISSUING ANY FIRE WEATHER HEADLINES AND ADDRESS IN HAZARDOUS WEATHER OUTLOOK. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...THESE FORECAST PERIODS CONTINUE TO BE TARGETED FOR A WEATHER SYSTEM MOVING THROUGH OR JUST TO THE WEST OF CO. CERTAINLY A COMPLEX WEATHER PATTERN WHEN POTENTIAL LOW PRESSURE SYSTEMS DEEPEN AND DROP SOUTH- SOUTHWESTWARD. THE 00Z/12 AND 06Z12 NAM-WRF IS THE WEAKEST WITH THE SOLUTION...WHILE THE 00Z/12 ECMWF IS MUCH STRONGER WITH THE CLOSED LOW. THE 00Z/12 GFS IS SOMEWHERE IN-BETWEEN. GFS AND ECMWF HAVE BEEN DOING BETTER THAN THE NAM-WRF...SO WILL LEAN HEAVILY TOWARDS THE GFS-ECMWF BLEND. A CLOSED LOW WILL LIKELY BE DEVELOPING AROUND THE FOUR CORNERS AREA LATE WEDNESDAY NIGHT AND THEN DROP SOUTHWARD INTO NM DURING THURSDAY- THURSDAY EVENING. MEANWHILE...A COLD FRONT IS FORECAST TO RACE THROUGH EASTERN CO. AGAIN...THIS PUTS SOUTHERN CO IN-BETWEEN TWO SYSTEMS. THE POTENTIALLY GREATEST SYNOPTIC SCALE ASCENT...PER MODEL KINEMATICS...COULD BE ACROSS CENTRAL AND SOUTH CENTRAL CO DURING WEDNESDAY NIGHT INTO THURSDAY AFTERNOON. -15C LEVEL DROPS BELOW 500MB NEAR THE CLOSED LOW AND IN THE TROUGH OVERHEAD ALONG WITH ADEQUATE MODEL PROJECTED UPWARD VERTICAL MOTION IN THIS LAYER. SURFACE TEMPERATURES ACROSS THE MOUNTAINS AND HIGH VALLEYS SHOULD BE IN THE SINGLE DIGITS TO 20S PROMOTING 20-1 TO 30-1 SNOW RATIOS. ALSO...KIND OF A MIDLEVEL "COL" SETTING UP OVER THE MOUNTAINS...WHICH COULD HELP WITH DEFORMATION BANDING PRECIPITATION ACROSS MUCH OF SOUTH CENTRAL CO. FURTHERMORE...AN ISENTROPIC ASCENT AREA DEVELOPS JUST SOUTH OF THE "COL" OVER NORTHERN NM AND THESE BANDS OF PRECIPITATION COULD MIGRATE NORTHWARD ACROSS THE NM/CO BORDER INTO THE SOUTHERN SAN LUIS VALLEY/SOUTHERN SANGRE DE CRISTO MOUNTAINS BY THURSDAY AFTERNOON. THE POTENTIAL FOR 12-24 HOUR WARNING CRITERIA COULD BE THE EASTERN SAN JUAN MOUNTAINS... SAN LUIS VALLEY...SANGRE DE CRISTO MOUNTAINS...WET MOUNTAINS/VALLEY... AND SOUTHERN FOOTHILLS...SO WILL GO WITH A WINTER STORM WATCH FOR WEDNESDAY EVENING THROUGH THURSDAY EVENING. ADVISORY NUMBERS COULD OCCUR AROUND THE WARNING AREA...BUT TOUGH CALL. FOR TELLER...EL PASO AND PUEBLO COUNTIES...A VERY DIFFICULT CALL AS THE CLOSE LOW WILL LIKELY BE TOO FAR WEST...HOWEVER THE COLD FRONT RACING DOWN THE PLAINS WILL BE A PLAYER. THE PALMER DIVIDE COULD SEE ADVISORY NUMBERS BY LATE WEDNESDAY NIGHT INTO THURSDAY. POTENTIAL FOR QPF/SNOW AMOUNT "SHADOW" TO DEVELOP ACROSS SOUTHERN EL PASO AND NORTHERN PUEBLO COUNTIES GIVEN THE STIFF NORTHERLY WIND AND LACK OF STRONG MIDLEVEL UPWARD VERTICAL MOTION...HOWEVER THERE WILL BE SOME LOW LEVEL FRONTOGENETICAL FORCING TO PRODUCE PRECIPITATION. OVERALL...ALWAYS A VERY TOUGH CALL WITH THIS STYLE OF STORM TRACK. IF IT IS A LITTLE FURTHER WEST...THEN NOT MUCH SNOW. IF IT IS A LITTLE FURTHER EAST...THEN SOUTH CENTRAL CO GETS SLAMMED WITH SNOW. THIS IS WHAT A WINTER STORM WATCH IS FOR AND SHOULD BE STRESSED. FRIDAY THROUGH MONDAY...NO CHANGES TO CURRENT FORECAST. METZE && .AVIATION... VFR CONDITIONS EXPECTED ACROSS THE REGION WITH ISOLATED SNOW SHOWERS CONFINED TO THE NORTHERN AND CENTRAL MTS. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY EVENING FOR COZ078>080-087-088. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING FOR COZ064>075. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 153 PM EST TUE FEB 12 2008 .SYNOPSIS... HIGH PRESSURE BUILDS INTO THE CANADIAN MARITIME REGION THROUGH TONIGHT...WITH PART OF IT REMAINING RIDGED DOWN INTO THE NORTHEASTERN UNITED STATES EAST OF THE APPALACHIANS. MEANWHILE...AN AREA OF LOW PRESSURE WILL DEVELOP OVER THE MID- SOUTH TODAY...AND MOVE TO THE CENTRAL APPALACHIANS BY WEDNESDAY MORNING. A COASTAL LOW WILL DEVELOP OFF THE VIRGINIA CAPES WEDNESDAY AFTERNOON...AND LIFT NORTHEAST INTO THE CANADIAN MARITIME REGION BY THURSDAY MORNING. WEAK HIGH PRESSURE THEN BUILDS IN TO OUR SOUTH THURSDAY AND THURSDAY NIGHT. A COLD FRONT WILL CROSS THE TRI-STATE FRIDAY AND FRIDAY EVENING...FOLLOWED BY ARCTIC HIGH PRESSURE BUILDING IN THROUGH SATURDAY NIGHT...THEN LIFTING NORTHEAST ON SUNDAY. AN AREA OF LOW PRESSURE WILL MOVE FROM THE SOUTHEASTERN STATES SUNDAY...TO THE NORTHEAST ON MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LIGHT SNOW OVERSPREADING THE REGION FROM SW TO NE THIS AFTERNOON AS SOLID ISENTROPIC LIFT DEVELOPS ACROSS THE REGION. WITH SUBSIDENCE INVERSION FROM HIGH TRANSITING OVERHEAD LIMITING MIXING TO AROUND 950 MB AND INCREASING CLOUDINESS...HIGHS WILL STRUGGLE TO REACH THE 25 TO 30 DEGREE RANGE (USED A BLEND OF NAM12 AND LAV HOURLY TEMPERATURES FOR HOURLY TEMPS AND TO DERIVE HIGHS FOR TODAY). WITH PLENTY OF COLD AIR IN PLACE...AND MOISTURE STREAMING IN AT ALL LEVELS...PRECIPITATION WILL START AS SNOW AT ALL LOCATIONS...WITH AROUND AN INCH OF ACCUMULATION LIKELY ACROSS WESTERN ZONES BY LATE AFTERNOON. ONLY MINOR TWEAKS BASED ON LATEST OBS/SAT/RAD/MOD TRENDS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... GENERALLY LIKE SREF HANDLING OF LOW TRACK...NAM LOW LEVEL THERMAL FIELDS THROUGH WEDNESDAY MORNING (THOUGH THEY MAY NOT BE COLD ENOUGH NEAR THE SURFACE AS SUGGESTED BY RECENT WARM FRONTAL PASSAGES...AND THAT A ALL BUT MET GUIDANCE IS UNDER CUTTING THEM AT THE SURFACE...SO FOLLOWED A BLEND OF THE COLDER GUIDANCE FOR HOURLY TEMPERATURES. WHAT HAS WORKED BEST SO FAR THIS WINTER FOR TEMPERATURES AHEAD OF A WARM FRONT...WITH COLD AIR DAMMING PRESENT HAS BEEN THE RUC13 2M TEMPERATURE...BUT THAT MODEL ONLY GOES OUT 12 HOURS...SO COULD NOT USE FOR THIS FORECAST)...AND A BLEND OF NAM/GFS/UKMET/ECMWF FOR QPF. ENOUGH COLD AIR DOES NOT WORK ITS WAY IN ALOFT TO CHANGE PRECIPITATION FROM ALL SNOW UNTIL JUST AFTER MIDNIGHT...FORTUNATELY BEST FRONTOGENIC AND ISENTROPIC FORCING DOES NOT COME IN UNTIL AFTER THEN (EXCEPT ACROSS FAR NW)...SO SNOW SHOULD GENERALLY BE LIGHT TO MODERATE...WITH SUB WARNING AMOUNTS...AND SUB ADVISORY AMOUNTS OVER THE CITY AND LONG ISLAND. COULD ACTUALLY END UP WITH A COUPLE HOURS OF SLEET BEFORE CHANGING TO FREEZING RAIN...HOWEVER NOT CONFIDENT IN THIS...SO OPTED TO REFLECT A BIT MORE FREEZING RAIN IN THE FORECAST. RESULT IS UPPED WINTER STORM WATCH TO A WINTER STORM WARNING OVER ORANGE AND WESTERN PASSAIC (2-5" SNOW AND AROUND 1/2 INCH OF ICE)...ESPECIALLY WHEN NOT EXPECTING TEMPS TO GET ABOVE FREEZING UNTIL AFTER 12Z. WENT WITH AN ADVISORY EVERYWHERE ELSE EXCEPT NYC AND LONG ISLAND...WHERE JUST DO NOT HAVE 80 PERCENT CONFIDENCE IN A GLAZE OF ICE. BEST CHANCE FOR THAT IN THE NON ADVISORY AREA IS ACROSS THE BRONX AND NORTHERN MANHATTAN...DAY SHIFT CAN EVALUATE NEED TO EXPAND ADVISORY. CAME CLOSE TO ISSUING WARNING FOR PUTNAM...BUT JUST ENOUGH UNCERTAINTY ON SNOW/ICE AMOUNTS...THAT PLAYED AS SOLID ADVISORY...THOUGH COULD BE UPGRADED BY DAY SHIFT IF IT IS FELT THAT A HALF AN INCH OF ICE COULD BE REACHED. WARM AIR SHOULD WIN THE RACE ULTIMATELY AND CHANGE ALL PRECIP TO RAIN BY MID MORNING (NW)...AND EVEN SOONER ELSEWHERE (THOUGH MIGHT BE A BIT TO FAST IN PUTNAM) WITH RISING TEMPERATURES TONIGHT...EASTERN SUFFOLK WILL BE THE FIRST TO CHANGE OVER...WITH OTHER LOCATIONS GOING OVER SE TO NW TONIGHT INTO WEDNESDAY MORNING. NOT ADDRESSED IN THE ZONES (BUT WILL BE MENTIONED IN THE HWO)...IS THE FLOODING POTENTIAL DUE TO HEAVY RAINFALL ON WEDNESDAY (NOTE STRONG OCEANIC INFLOW WITH IMPRESSIVE ISENTROPIC LIFT AND FRONTOGENIC FORCING (ESPECIALLY OVER EASTERN ZONES). SEE HYDROLOGY SECTION FOR EXPECTED QPF AMOUNTS AND IMPACTS. GFS APPEARS TO BE AN OUTLIER IN IT DEVELOPING A TERTIARY COASTAL LOW...THAT IT HAS BRINGING MORE PRECIPITATION IN WEDNESDAY NIGHT AND THURSDAY...SO HAVE THROWN OUT...AND WENT WITH SREF LED CONSENSUS IDEA OF THINGS DRYING OUT LATE WEDNESDAY AFTERNOON AND EVENING FROM WEST TO EAST AS LOW PULLS AWAY. WILL BE A BIT OF WIND WITH THE SYSTEM...THOUGH SHOULD EB BELOW ADVISORY LEVELS. FOR NOW GOING WITH DRY FORECAST THURSDAY WITH WEAK HIGH PRESSURE BUILDING IN...AND NEAR NORMAL TEMPERATURES. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LITTLE TIME TO EVALUATE THE EXTENDED OVERNIGHT...BUT FROM WHAT I SAW...FORECAST SEEMED IN GENERAL ON TRACK...SO ONLY CHANGES MADE IN GRIDS WERE TO IMPROVE CONSISTENCY BETWEEN OFFICES. PREVIOUS LONG TERM DISCUSSION FOLLOWS (WITH REFERENCES TO THURSDAY (DURING THE DAY) REMOVED)... HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT WITH DRY CONDITIONS EXPECTED THROUGH FRIDAY. THE NEXT COLD FRONT WILL SWEEP ACROSS THE AREA OVERNIGHT ON FRIDAY. MOISTURE WILL BE FAIRLY LIMITED WITH THIS SYSTEM...ALTHOUGH TEMPERATURES WILL BE COLD ENOUGH TO SUPPORT A CHANCE OF SNOW THROUGH EARLY SATURDAY MORNING. COLD AIR ADVECTION BEHIND THE COLD FRONT WILL ENSURE PLENTY OF COLD AIR IN PLACE AHEAD OF THE NEXT SYSTEM. DUE TO UNCERTAINTY IN TRACK...WE OPTED FOR A COMPROMISE BETWEEN HPC GRIDS AND GMOS WITH A CHANCE OF SNOW ACROSS THE AREA SUNDAY NIGHT INTO MONDAY. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... LIGHT AND VARIABLE WINDS EARLY THIS AFTERNOON WILL BECOME SE 5 TO 10 KT AS SFC HIGH PRES SLIDES EAST OF THE TERMINALS. IFR VSBY/LOW MVFR/IFR CIGS DEVELOPING ACROSS WESTERN TERMINALS AS A BAND OF LIGHT SNOW WORKS NE INTO THE REGION. EXPECT MVFR CONDS IN LIGHT SNOW TO WORK EAST INTO EASTERN TERMINALS BETWEEN 19Z AND 22Z. CIGS/VSBYS WILL BE DROPPING TO IFR AND LOWER THIS EVENING THROUGH WED. AT THE ONSET...PRECIP WILL BE ALL SNOW. PTYPE BECOMES PROBLEMATIC THIS EVENING INTO TONIGHT AS WARMER AIR SURGES NORTHWARD. FOR KNYC AND COASTAL TERMINALS...WILL EXPECT A PERIOD OF SNOW...POSSIBLY MIXED WITH SLEET THROUGH ABOUT 04Z...THEREAFTER EXPECT A QUICK TRANSITION TO RAIN. INLAND TERMINALS WILL BE MOST PROBLEMATIC. KSWF AND KHPN WILL START OUT AS SNOW...MIXING WITH FREEZING RAIN AND SLEET AFTER 03Z. FOR KSWF...THERE WILL BE A PROLONGED PERIOD OF FREEZING RAIN...CHANGING OVER WED MORNING. PRECIP AT KHPN SHOULD CHANGE TO PLAIN RAIN BETWEEN 09Z AND 11Z. LIFR CONDITIONS IN RA...HEAVY AT TIMES...EXPECTED LATE TONIGHT INTO EARLY AFTERNOON. FZRA AT KSWF. 50+ 2KFT LLJ KT WORKS OVER THE REGION LATE TONIGHT INTO WED MORNING...CREATING SOME LLWS ISSUES. SE WINDS WILL BE INCREASING TO 10-15 KT TONIGHT...THEN WINDS WILL BECOME TRICKY LATE TONIGHT AS A COASTAL FRONT DEVELOPS. MOST LIKELY IT WILL DEVELOP ACROSS THE NYC TERMINALS TOWARDS DAYBREAK AND THEN SLIDE NW AS COASTAL LOW PRESSURE DEVELOPS. WINDS TO THE S AND E OF THE FRONT WILL BE SOUTHERLY AND TO THE N AND E OF THE FRONT IT WILL BE NORTHEASTERLY. BEST GUESS RIGHT KNOW IS THAT KWSF WILL HAVE N/NE WINDS LATE TONIGHT INTO WED AND THEN THE REMAINDER OF THE TERMINALS WILL BE SOUTHERLY...BUT THIS WILL HAVE TO BE ADJUSTED AS TIMING NEARS. OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY...RAIN ENDS AND CONDITIONS IMPROVE TO VFR FROM W TO E LATE WED NIGHT. VFR THEN IN PLACE THU/FRI. ANOTHER COLD FRONT WILL MOVE ACROSS THE AREA FRI NIGHT/EARLY SAT. && .MARINE... TRANQUIL WINDS AND SEAS THIS AFTERNOON AS HIGH PRESSURE MOVES ACROSS THE WATERS. A RATHER UNSETTLED PERIOD IS FORECAST TONIGHT INTO THU AS A FRONTAL SYSTEM IMPACTS THE WATERS...PRECEDED AND FOLLOWED BY SCA CONDITIONS. LOW PRESSURE OVER THE MID MS VLY TRACKS INTO THE OHIO VALLEY TODAY...WHILE ITS WARM FRONT MOVES NORTHWARD ALONG THE MID ATLANTIC COAST. HIGH PRESSURE RETREATS EAST OF THE WATERS BY THIS EVENING. BETWEEN THE DEPARTING HIGH AND APPROACHING FRONTAL SYSTEM....SE WINDS WILL STRENGTHEN TO SCA CRITERIA OVERNIGHT WITH SEAS RAPIDLY BUILDING. BY 12Z WED...SEAS ARE FORECAST TO RANGE FROM 5 FT TO 10 FT ON THE OCEAN AND 2 TO 4 FT ACROSS LI SOUND. THE WARM FRONT MOVES NORTH OF THE WATERS AROUND 12Z WED...FOLLOWED BY A COLD FRONTAL PASSAGE AROUND 18Z. A STRENGTHENING LOW-LEVEL JET WED MORNING REACHES 60 KT...BUT THE LOW-LEVELS BECOME STRONGLY INVERTED WITH THE APPROACH OF THE WARM FRONT. THIS SHOULD KEEP WIND GUSTS FROM REACHING GALE CRITERIA. THE GRADIENT SLACKENS ENOUGH AFTER 12Z WED FOR NY HARBOR AND THE WESTERN SOUND TO DROP BELOW SCA CRITERIA. ELSEWHERE WINDS WILL BE MARGINAL...BUT SEAS ON THE OCEAN WILL BE WELL ABOVE 5 FT. COLD ADVECTION WED NIGHT WILL BRING WINDS BACK UP TO SCA CRITERIA ON ALL WATERS. THIS IS EXPECTED TO BE SHORT LIVED THOUGH AS HIGH PRESSURE BUILDS INTO THE WATERS THU AFT. ANOTHER FRONTAL SYSTEM IMPACTS THE AREA FRI EVE WITH STRONG COLD ADVECTION TO FOLLOW ON SAT WITH SCA CONDITIONS LIKELY TO RETURN ON ALL WATERS. && .HYDROLOGY... POTENTIAL FLOODING CONCERNS ON WEDNESDAY WITH 1-2 INCHES (WITH HIGHER AMOUNTS) CURRENTLY FORECAST. THIS WILL AT LEAST CAUSE MINOR FLOODING IN POOR DRAINAGE AREAS...AND COULD ALSO CAUSE FLASH FLOODING ISSUES OVER AREAS WITH A SIGNIFICANT ICE COATING (WITH TEMPERATURES NOT EXPECTED TO GET TO 40 OVER THE NW ON WEDNESDAY WILL HAVE LIMITED MELTING OF THE ICE...SO ALL RAIN WILL RUNOFF...AND OVER EASTERN AREAS...WHERE THERE IS THE SIGNAL OF POSSIBLE BANDING (STRONG FRONTOGENIC FORCING IN FAVORED NW QUADRANT OF COASTAL LOW) THAT COULD LOCALLY ENHANCE PRECIPITATION AMOUNTS. WILL REFLECT CONCERNS IN HWO. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR CTZ005>012. WINTER WEATHER ADVISORY UNTIL 5 AM EST WEDNESDAY FOR CTZ005>012. NY...WINTER STORM WARNING UNTIL 9 AM EST WEDNESDAY FOR NYZ067. FLOOD WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR NYZ068>076. WINTER WEATHER ADVISORY UNTIL 5 AM EST WEDNESDAY FOR NYZ069>071. WINTER WEATHER ADVISORY UNTIL 9 AM EST WEDNESDAY FOR NYZ068. NJ...WINTER STORM WARNING UNTIL 9 AM EST WEDNESDAY FOR NJZ002. FLOOD WATCH FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR NJZ003>006-011. WINTER WEATHER ADVISORY UNTIL 5 AM EST WEDNESDAY FOR NJZ003>006-011. MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EST WEDNESDAY FOR ANZ330-340-345. SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR ANZ335-338. SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EST WEDNESDAY FOR ANZ350-353-355. && $$ ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 700 PM EST MON FEB 11 2008 .SYNOPSIS... ARCTIC AIR WILL CONTINUE TO BE FELT ACROSS THE REGION THROUGH TONIGHT WITH WINDS SUBSIDING THROUGH THE EVENING HOURS. IN ADDITION...LAKE EFFECT SNOWS WILL DIMINISH WEST OF THE CAPITAL REGION AS HIGH PRESSURE BUILDS EASTWARD FROM THE OHIO VALLEY THIS EVENING. A COMPLEX STORM SYSTEM FORECAST TO LIFT NORTHEAST ACROSS THE APPALACHIANS...WILL BRING A POTENTIAL SIGNIFICANT WINTER STORM TO THE REGION TUESDAY AFTERNOON INTO WEDNESDAY. COLDER AIR IS POISED TO RETURN FOR THE MID WEEK PERIOD. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... LAKE EFFECT SNOW OFF LAKE ONTARIO CONTINUES TO REMAIN PROBLEMATIC. REPORTS OF ROAD CLOSURES ACROSS SOUTHERN HERKIMER COUNTY AND TYX RADAR TRENDS SUPPORTS ADDITIONAL SNOWFALL ACROSS THE SAME LOCATIONS. HOURLY RUC13...NAM12 AND LOCAL HIRESWRF GUIDANCE SUPPORT THE NOTION OF EXTENDING THE ADVISORY A BIT LONGER INTO THE EVENING HOURS. 1000-850MB WIND TRAJECTORY AROUND 290 DEGREES WITH MODERATE INSTABILITY IN PLACE AND HEALTHY CONVERGENT SIGNATURES TO KEEP THIS BANDING GOING THROUGH THE EVENING...WITH A JOG TO THE NORTH EXPECTED. ONCE THIS BANDS LIFTS NORTH...INVERSION HEIGHTS ARE EXPECTED TO BE LOW ENOUGH TO PRECLUDE ADDITIONAL SNOWFALL AMOUNTS ACROSS NORTHERN HERKIMER COUNTY. MEANWHILE...THE REMAINDER OF THE REGION...CU/SC IN PLACE SHOULD QUICKLY DISSIPATE WITH THE LOSS OF "HEATING" WITH DEWPOINTS AT OR BELOW 0C. THIS SHOULD RESULT IN A FAST DROP IN TEMPERATURES THIS EVENING. && .SHORT TERM /MIDNIGHT TONIGHT THROUGH WEDNESDAY/... TEMPERATURES BY SUNRISE TUESDAY SHOULD BE RATHER COLD WITH NEARLY CLEAR SKIES (OUTSIDE OF SCT LAKE CLOUDS) AND LIGHT WINDS WITH 1030MB SURFACE HIGH IN PLACE. WENT INTO THE SINGLE DIGITS FOR MOST LOCATIONS...BELOW ZERO FOR THE ADIRONDACKS AND THE VALLEYS INTO SOUTHERN VT. WHILE WE BEGIN THE DAY ON A SUNNY NOTE...PLENTY OF DISCUSSION CONCERNING UPCOMING SIGNIFICANT EVENT. IMPRESSIVE MOISTURE TRANSPORT IS EXPECTED AND EXAMINATION OF THE H2O VAPOR LOOP...REVEALS AMPLE MOISTURE ACROSS THE WESTERN GULF OF MEXICO AND POTENT MID LEVEL CONVERGENCE EXTENDING INTO THE OHIO RIVER VALLEY. SHORT WAVE WAS DIVING SOUTHWARD ACROSS THE ROCKIES ACCOMPANIED BY A 130KT JET. ALL OF THESE FEATURES ALONG WITH INCREASING BAROCLINICITY ARE EXPECTED TO CONVERGE ACROSS THE EASTERN CONUS TUESDAY AFTERNOON. GFS/NAM/CANADIAN ALL REVEAL STRONG ISENTROPIC UPGLIDE NICELY SHOWN ON THE 290K SURFACE WITH WIND SPEEDS IN EXCESS OF 50KTS! WITH RAPIDLY DESCENDING CPD/S...AND THE COLUMN EXPECTED TO REMAIN BELOW FREEZING...WILL SEE THE SNOW DEVELOP FROM SOUTHWEST TO NORTHEAST THROUGHOUT THE AFTERNOON. UP TO A COUPLE OF INCHES OF SNOW EXPECTED BY THE EVENING HOURS WITH THE BULK OF THE ACTIVITY EXPECTED TUESDAY NIGHT. STILL OUTSTANDING CONCERNS WITH EVOLVING PRECIP EVENT AND TYPE. ENSEMBLE MEMBERS FROM THE MREF INDICATE A GOOD BURST OF SNOW...TRANSITIONING TO SLEET/FZRA TOWARD MIDNIGHT THEN THE FREEZING LINE HOVERING AROUND THE MOHAWK VALLEY AND SOUTHERN VT THROUGH THE REMAINDER OF THE OVERNIGHT PERIOD. CROSS SECTIONS FROM THE NAM/GFS SUGGEST A HEALTHY FGEN FORCING COINCIDING WITH A LAYER OF -EPV. SO COULD SEE A CONVECTIVE BURST WITH GOOD SNOWFALL RATES. FURTHERMORE...MAX LIFT DURING THE EVENING OCCURS WITHIN THE FAVORABLE DENDRITIC ICE GROWTH REGION. GIVEN THE COMPLEXITY OF PRECIP TYPES...WE WILL HOLD ONTO THE WATCH AT THIS TIME. IN ADDITION...GIVEN THE COLDER TEMPS EXPECTED ACROSS THE HIGHER TERRAIN OF NW CT...WILL EXTEND THE WATCH THERE. NOW THE POSSIBILITY EXISTS FOR A DEFORMATION AXIS TO BE IN PLACE ACROSS THE EASTERN HALF OF THE CWA THROUGH WEDNESDAY AS COLDER AIR WRAPS IN THE BACKSIDE OF DEPARTING SYSTEM. THIS COULD ADD ADDITIONAL ACCUMULATIONS TO THE REGION AND WILL CONTINUE TO MONITOR TRENDS (ONCE WE SEE HOW TUESDAY NIGHT EVOLVES). && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... ONCE WEDNESDAY`S MESSY STORM DEPARTS BY WEDNESDAY NIGHT... IT LOOKS AS IF WE WILL GET A BRIEF BREAK IN STORM WEATHER AS THE POLAR JET STREAM AND SUBTROPICAL JETSTREAM BECOME BRIEFLY BIFURCATED AGAIN. HIGH PRESSURE BUILDS TO OUR SOUTH TO GIVE US A DRY DAY ON THURSDAY WITH SOME SUNSHINE (A RARE COMMODITY THIS MONTH). THEN...A WEAK SYSTEM (A CLIPPER TYPE STORM) COULD BRING SOME LIGHT SNOW OR RAIN SHOWERS TO THE AREA COME FRIDAY. WHILE WEAK...IT WILL BRING ANOTHER PRETTY STRONG COLD FRONT THROUGH THE AREA BY FRIDAY NIGHT...BRINGING ANOTHER SHOT OF COLD AIR FOR SATURDAY. AFTER THAT...IT APPEARS THAT THE SOUTHERN JET WILL BECOME ACTIVE ONCE AGAIN. EARLIER RUNS OF THE EUROPEAN HAD A SOUTHERN STREAM SYSTEM SLIPPING OFF TO THE SOUTH. NOW...THIS MODEL AS WELL AS THE GFS...TRACK THE A STORM FROM TEXAS...EAST OF THE APPALACHIANS...AND FORMS A SECONDARY LOW TO THE EAST...ANOTHER "DOUBLE-SPLITTER." BOTH MODELS INFER THAT THERE MIGHT BE ENOUGH WARM AIR FOR A MIX...OR POSSIBLY A CHANGEOVER TO LIQUID RAIN. FOR NOW...WE CALL IT MAINLY SNOW GIVEN THE SEASON AND COLDER GMOS TEMPS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THE SFC PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM SOUTHERN ONTARIO AND THE GREAT LAKES REGION...AND LOW PRESSURE NEAR THE LABRADOR SEA HAS FINALLY BEGUN TO WEAKEN. HIGH PRESSURE WILL BRIEFLY MOVE OVER THE NORTHEAST OVERNIGHT. LOW PRESSURE WILL APPROACH FROM THE MIDWEST TUE PM WITH ITS ASSOCIATED WARM FRONT BRINGING SNOW INTO SRN NY /KALB SOUTH/ AFTER 21Z. VFR CONDITIONS WILL PREVAIL PRIOR TO 21Z TUE. THE W/NW WINDS WILL GENERALLY BE 10 KTS OR LESS PRIOR TO 06Z. THE WINDS WILL BECOME LIGHT TO CALM 06Z-09Z. CIRRUS WILL BEGIN TO INCREASE FROM THE SOUTH AND WEST 15Z-18Z. THE CLOUDS WILL THICKEN AND LOWER THROUGH THE AFTERNOON WITH SNOW MOVING INTO KPOU AND KALB AFTER 21Z. EXPECT CIGS AND VSBYS TO QUICKLY LOWER TO MVFR LEVELS 21Z TUE TO 00Z WED IN THE SNOW. THE WINDS WILL BE FROM THE E/SE AT 5 KTS OR LESS IN THE PM. OUTLOOK... TUE NIGHT THROUGH WED...MVFR/IFR...SNOW OR WINTRY MIX LIKELY. THU...VFR...NO SIG WX. FRI...MVFR/IFR...CHC SNOW OR WINTRY MIX. SAT...VFR...NO SIG WX. && .HYDROLOGY... ARCTIC AIRMASS HAS RESULTED IN ICE BUILD UP AND FORMATION ON RIVERS. LAKE EFFECT WILL FINALLY WIND DOWN THIS EVENING. ANOTHER COMPLEX SYSTEM ON TAP FOR TUESDAY AFTERNOON INTO WEDNESDAY AFTERNOON WITH P-TYPE ISSUES. AT THIS TIME IT APPEARS SNOW TO THE NORTH AND WEST OF THE CAPITAL REGION WITH SNOW...SLEET AND FREEZING RAIN TO THE SOUTH AND EAST WITH A CHANGEOVER TO PLAIN RAIN POSSIBLE OVER THE SOUTHERN MOST PORTION OF THE FORECAST AREA. WITH MOST OF THE QPF EITHER FROZEN OR FREEZING DO NOT EXPECT PROBLEMS BUT BEARS WATCHING...ESPECIALLY FOR THE MID HUDSON VALLEY AND NORTHWEST CONNECTICUT. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...WINTER STORM WATCH TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR CTZ001. NY...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR NYZ032-033-038>043-047>054-058>061-063-082>084. LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR NYZ038. MA...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR MAZ001-025. VT...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR VTZ013>015. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...HWJIV AVIATION...WASULA HYDROLOGY...BGM/SD FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY ct AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MIAMI FL 740 PM EST TUE FEB 12 2008 .UPDATE... ...TORNADO WATCH IN EFFECT FOR ALL OF SOUTH FLORIDA UNTIL 11 PM EST... SENT A QUICK UPDATE TO THE FORECAST FOR THE OVERNIGHT HOURS BUT NOT MUCH WAS CHANGED OTHER THAN TO REFLECT CURRENT TRENDS. NOW CONCERNING THE SEVERE WEATHER POTENTIAL THIS EVENING...LATEST RADAR IMAGERY SHOWS 2 VERY STRONG, SUSTAINED SUPERCELLS 50 TO 60 MILES OFFSHORE THE SOUTHWEST FLORIDA COAST MOVING SLOWLY EAST TO EAST NORTHEAST WITHIN A BAND OF CONVECTIVE RAINFALL...AND OTHER SCATTERED HEAVY CONVECTIVE SHOWERS AND ISOLATED THUNDERSTORMS. THIS BAND WAS MOVING ONSHORE ALONG THE SOUTHWEST FLORIDA COAST AS THE OVERALL BAND MOVES SLIGHT EAST SOUTHEAST TOWARDS HIGHER INSTABILITY. LATEST ANALYSIS/GUIDANCE SHOWS THAT THESE STORMS WERE BEING SUSTAINED WITHIN THE INSTABILITY AXIS EXTENDING FROM THE EAST CENTRAL GULF INTO THE FLORIDA STRAITS...WHERE CAPES AS HIGH AS 3000 J/KG WERE BEING OBSERVED...AND ON THE TAIL END OF THE LEAD SUBTROPICAL SHORTWAVE TROUGH MOVING THROUGH THE EASTERN GULF. THE GREATEST THREAT FOR ANY SEVERE WEATHER/ATTENDANT ISOLATED TORNADO THREAT SHOULD BE BETWEEN NOW AND MIDNIGHT OR SHORTLY THEREAFTER...AS MODEL GUIDANCE INCLUDING LOCAL WRF RUN AND 40KM RUC SUGGEST THE SHORTWAVE WILL BEGIN MOVING NORTH OF THE REGION DURING THIS TIME AND WILL INDUCE A SURGE OF THE WEAK SURFACE WARM FRONT/BAROCLINIC ZONE NORTH THROUGH THE REGION...WITH MID-LEVEL DRY PUNCH MOVING TOWARDS THE SOUTH FLORIDA PENINSULA. IN ADDITION...MODEL DIAGNOSED UPPER LEVEL DIVERGENCE WILL BE HIGHEST IN THIS TIME PERIOD. LOW LEVEL HELICITIES CONTINUE OVER 100 M2/S2 WITH BACKED SE SURFACE FLOW...HOWEVER INSTABILITY OVER LAND IS MUCH LESS THAN OVER THE WATER WITH CAPES GENERALLY LIMITED TO AROUND 1000 J/KG. 00Z MIAMI UPPER AIR SOUNDING SHOWS AROUND 1100 J/KG SURFACE BASED CAPE WITH 0-3KM HELICITIES CLOSE TO 300 M2/S2. WITH ALL THAT SAID...IT APPEARS THAT THE GREATEST THREAT FOR ISOLATED TORNADOES THROUGH THE EARLY MORNING HOURS WILL LIE ACROSS THE SOUTHERN PART OF THE CWA WHERE THE GREATEST INSTABILITY EXISTS WITHIN THE LOW LEVEL SHEAR ZONE...BUT THAT DOES NOT MEAN TORNADO THREAT CANNOT BE RULED OUT FURTHER NORTH NEAR THE LAKE OKEECHOBEE REGION. && .AVIATION... MAIN FOCUS FOR CONVECTION DURING FIRST FOUR HOURS OF THIS FORECAST PERIOD WILL BE ACROSS WESTERN HALF OF PENINSULA...WITH ACTIVITY MOVING ONSHORE FROM ADJACENT PORTIONS OF SOUTHEAST GULF. THUS... WILL CARRY PREVAILING VCTS/CB FOR KAPF AND ONLY MENTION VCSH FOR ATLANTIC COAST TERMINALS. THUNDERSTORM THREAT WILL INCREASE AFTER 13/04Z FOR EAST COAST...AS LOW-LEVEL JET INTENSIFIES IN RESPONSE TO STRONG CYCLOGENESIS OVER THE LOWER MISSISSIPPI VALLEY...AND WILL MAINTAIN VCTS/CB FOR ALL TERMINALS THROUGH END OF FORECAST PERIOD. OTHERWISE...EXPECT BKN VFR CIGS TO PERSIST THROUGH THE PERIOD. MODERATE SOUTHEAST SURFACE FLOW WILL INCREASE SUBSTANTIALLY WITH ONSET OF LOW-LEVEL JET LATER TONIGHT...AND WILL INCREASE SUSTAINED SPEEDS TO 15G25. EVEN STRONGER WIND SPEEDS EXPECTED TOMORROW...AS FLOW VEERS TO SOUTHWEST IN ADVANCE OF APPROACHING TROUGH. SUSTAINED SPEEDS AND GUSTS WILL BOTH DIMINISH BY END OF FORECAST PERIOD. && .MARINE... ONLY CHANGE WAS TO RE-ISSUE THE SCA FOR BISCAYNE BAY THROUGH THE NIGHT BASED ON CURRENT OBS AND TIGHTENING PRESSURE GRADIENT. UPDATE: STRASSBERG/DD && .PREV DISCUSSION... /ISSUED 349 PM EST TUE FEB 12 2008/ ..TORNADO WATCH IN EFFECT FOR ALL OF SOUTH FLORIDA UNTIL 11 PM EST THIS EVENING... SYNOPSIS...A LARGE AMPLITUDE LONG WAVE TROUGH EXTENDING FROM JUST WEST OF THE G. LAKES S-SW TO NRN MEX WITH A SERIES OF SHORT WAVES MOVING EAST ARND THE BASE OF THE TROUGH. FIRST SIGNIFICANT S/W ACROSS E-CENTRAL GULF OF MEX ATTM. ANOTHER MORE VIGOROUS S/W OVR E TX. ATTM. AT THE SFC...A WARM FRONT MOVING NORTH ACROSS SOUTHERN TIP OF FL PENINSULA AT THE MOMENT WITH NMRS SHOWERS/ISOLD TSTMS SPREADING NORTH. COLD FRONT EXTENDING FROM TN SW TO SWRN TX. SHORT TERM...TONIGHT...LATEST MDLS SHOW WARM FRONT MOVING N TO CENTRAL FLORIDA BY 00Z WHILE AT THE SAME TIME THE 1ST SHORT WAVE MOVES THROUGH THE AREA. BOTH GFS AND NAM SHOW VERY GOOD UPR LVL DIV AHEAD OF THE S/W WITH A STG 850MB INFLOW (30 TO 45 KTS) MAINLY FROM LAKE OKEE NORTHWARD. THIS SEEMS TO INDICATE THAT NRN PORTION OF S. FL (COUNTIES SURROUNDING LAKE OKEE) WILL EXPERIENCE MOST OF WX AS MOST PARAMETERS COINCIDE OVR THAT AREA TONIGHT. THE ONLY FLY IN THE OINTMENT IS THE ABSENCE OF A SFC FORCING MECHANISM AS THE WARM FNT WILL ALREADY BE NORTH OF THE AREA. STILL LOW LVL CONVERGENCE SHOULD BE STRONG ENOUGH TO RESULT IN WIDESPREAD TSTM ACTIVITY WITH A FEW BECOMING STG. WEDNESDAY...S/W OVER TX WILL DIG SE PUSHING THE COLD FRONT ANOTHER ROUND OF STORM WILL AFFECT THE AREA WEDNESDAY BY 18Z. A SQUALL LINE WILL DEVELOP AHEAD OF THE COLD FNT AND MOVING THROUGH S. FL WED AFTERNOON. THE QUESTION IS, HOW STRONG THIS SQUALL LINE IS GOING TO BE WHEN IT MOVES THROUGH THE AREA. MDLS SHOW LOW LVL WINDS VEERING TO SW AHEAD OF THE LINE DISRUPTING THE INFLOW AND WEAKENING THE LINE. STILL WILL EXPECT A FEW STORMS TO MAKE IT THROUGH THE AREA. WITH AN UNIDIRECTIONAL SFC TO 700 MB SHEAR WILL EXPECT BIGGEST THREAT WITH THESE STORMS TO BE DAMAGING WINDS (40 TO 50 MPH) AT BEST. GFS INDICATES THIS LINE WILL ACTUALLY SLOW DOWN WITH A FEW SHWRS/TSTMS LINGERING THROUGH THE AFTERNOON. CD FNT SHOULD MOVE SOUTH OF MIA BY 06Z THU WITH DRYING TREND STARTING QUICKLY AFTER FROPPA. LONG TERM...THURSDAY THROUGH SUNDAY...AFTER FROPA WED NIGHT...DRIER AIR SHOULD FILTER SOUTH TO SOUTH FLORIDA WITH BASICALLY DRY CONDITIONS THROUGH THE HOLD PERIOD. AVIATION...CEILINGS OCCASIONALLY AROUND 3 TO 5KFT ARE EXPECTED TO CONTINUE THROUGH THIS EVENING, WITH BRIEF LOWER CEILINGS IN THE EVENING AS MOISTURE INCREASES. SHOWER AND THUNDERSTORM COVERAGE IS ALSO EXPECTED TO INCREASE THIS EVENING AND REMAIN ELEVATED TONIGHT AND INTO WEDNESDAY. WINDS ARE GENERALLY EXPECTED TO REMAIN EAST TO SOUTHEAST THROUGH THE REST OF THIS AFTERNOON AND GRADUALLY BECOME MORE SOUTHERLY OVERNIGHT. SPEEDS ARE EXPECTED TO BE IN THE 12 TO 16 KT RANGE WITH GUSTS IN THE LOW 20S, HOWEVER WINDS MAY BECOME VARIABLE AND INCREASE IN SPEED IN AND AROUND STORMS. MARINE...SFC WNDS WILL INCREASE TONIGHT AND BECOME S-SW AS THE SFC LOW/FNT OVER SRN PLAINS DEEPENS. SFC WINDS SHOULD VEER TO NW BEHIND THE COLD FNT AND BRIEFLY REMAIN AT 15 TO 20 KTS WED NIGHT BEFORE SUBSIDING TO BELOW 15 KTS AFTERWARDS. FIRE WEATHER...RH VALUES WILL DROP SIGNIFICANTLY BY THU AFTERNOON AS DRY AIR FILTER SOUTH BEHIND THE FNT. RH COULD HOVER ARND 35 PERCENT FOR A FEW HOURS. RH VALUES WILL RECOVER QUICKLY BY FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 69 81 56 75 / 90 70 30 10 FORT LAUDERDALE 71 81 60 77 / 90 70 30 10 MIAMI 70 82 60 78 / 90 70 30 10 NAPLES 68 77 56 76 / + 70 20 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...TORNADO WATCH 53 IN EFFECT UNTIL 11 PM EST THIS EVENING. AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST WEDNESDAY FOR AMZ650-AMZ651- AMZ670-AMZ671. SMALL CRAFT ADVISORY UNTIL 7 PM EST WEDNESDAY FOR AMZ630. GM...NONE. && $$ LONG TERM...47/RHG SHORT TERM/AVIATION...04/AT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 950 PM EST MON FEB 11 2008 .DISCUSSION... ...STRONG TO SEVERE STORMS WITH HEAVY RAIN POSSIBLE LATE TUESDAY INTO WEDNESDAY... CURRENT...CURRENT RUC40 SURFACE ANALYSIS WAS SHOWING HIGH PRESSURE MOVING OFF THE VA/NC COAST AND INTO THE WESTERN ATLANTIC WHILE EASTERLY FLOW IS MAINTAIN AS THE CENTER OF THE HIGH SHIFTS INTO THE ATLANTIC. LATEST IR SATELLITE LOOP WAS SHOWING ADVANCING CIRRUS SHIELD ASSOCIATED WITH A DEVELOPING LOW OVER THE CENTRAL GULF OF MEXICO SLOWLY EXPANDING EASTWARD. OF NOTE ON THE WATER VAPOR LOOP IS A BULGE ON THE BACKSIDE OF THE DEVELOPING LOW AS A VORTICITY MAX MOVES THROUGH THE SYSTEM. FORECAST LOOKS TO BE IN GOOD SHAPE. NO UPDATE PLANNED. && .AVIATION...VFR. WILL SEE HIGH CLOUDS THICKEN OVERNIGHT AND INTO TUE MORNING. PCPN CHANCES INCREASE TUE AFTN FROM SOUTH AND THERE WILL BE AN ISOLD THUNDER CHANCE BY MID/LATE AFTN. MVFR CIGS/VSBYS INVOF PCPN TUE AFTN. && .MARINE...LATEST BUOY OBS WERE SOUTHEAST AROUND 16 KNOTS AND 4 FOOT SEAS. WILL AMEND THE WIND GRIDS TO BETTER MATCH OBS AND TRENDS. WILL HEADLINE CAUTION FOR 15-20 KNOTS OVERNIGHT ACROSS MUCH OF THE WATERS WITH THE POSSIBILITY OF ADVISORIES BEING NEEDED TUE. && .PREV DISC... TUE...NEAR ZONAL FLOW ALOFT RAPIDLY BECOMES SOUTHWESTERLY EARLY IN THE PERIOD AS A LARGE UPPER TROUGH SWINGS OUT OF THE PLAINS INTO THE MIDWEST AND TOWARDS THE MISSISSIPPI VALLEY BY LATE IN THE DAY. ALSO BY THIS TIME A COLD FRONTAL BOUNDARY WILL HAVE ADVANCED INTO THE GULF COAST STATES OF LOUISIANA AND MISSISSIPPI. CLOSER TO HOME...ISENTROPIC UPGLIDE WILL ALLOW THE ATMOSPHERE TO MOISTEN DURING THE MORNING AND AFTERNOON FROM THE TOP DOWN. AS SUCH...ONLY MEAGER PCPN CHANCES AROUND TUE MORNING (HIGHER SOUTH)...THOUGH THEY WILL GRADUALLY INCREASE THROUGH THE AFTERNOON. EAST/SOUTHEAST WINDS EARLY IN THE PERIOD WILL VEER TO OUT OF THE SOUTHEAST AS DEWPOINTS CLIMB SEVERAL DEGREES DURING THE DAY IN ASSOCIATION WITH A WARM FRONT THAT WILL ADVANCE FROM SOUTH FLORIDA NORTHWARD THROUGH THE AFTERNOON. THE WINDS WILL APPROACH BREEZY STATUS DURING THE DAY...ESPECIALLY ALONG THE COAST AND OVER THE SOUTH. EXPECT CLOUD COVER TO THICKEN DURING THE DAY KEEPING MAX TEMPERATURES IN CHECK WITH MIDDLE 70S NORTH AND UPPER 70S FURTHER SOUTH. WILL TAPER PCPN CHANCES UPWARD IN THE AFTN TO HIGH END CHC NORTH (50%) AND LIKELY (60-70%) SOUTH. KEEP IN MIND THAT INCREASED RAIN CHANCES NORTHWARD WILL BE MAINLY FROM MID/LATE AFTN. ATMOSPHERIC INSTABILITY WILL BE AT A MINIMUM DURING THE AFTERNOON BUT A SCHC THUNDER MENTION IS WARRANTED NONETHELESS. TUESDAY NIGHT-WED...RATHER STRONG HIGH PRESSURE WILL PUSH EAST OF THE AREA AND A LONG FETCH OF SOUTHERLY FLOW WILL TAP DEEP MOISTURE OUT OF THE TROPICS TUE NIGHT. A CONVECTIVE COMPLEX ASSOCIATED WITH WEAK SOUTHERN STREAM UPPER IMPULSE MAY TRACK QUICKLY EAST ACROSS THE EASTERN GULF/SOUTHERN PENINSULA ALONG WEAK WARM FRONT. WHATEVER CONVECTION THAT DEVELOPS WITH THIS INITIAL IMPULSE WILL BE IN AN ENVIRONMENT OF INCREASING LOW LEVEL SHEAR. DEEP LAYER SHEAR WILL INCREASE DURING THE NIGHT AS VIGOROUS SHORTWAVE TROUGH MOVES ACROSS THE SOUTHEAST STATES. ASSOCIATED SURFACE LOW IS PROGGED TO DEVELOP AHEAD OF THE TROUGH AND DEEPEN AS IT MOVES ACROSS THE CAROLINAS ON WED. UPPER DIVERGENCE WILL INCREASE AND A SQUALL LINE MAY DEVELOP AHEAD OF APPROACHING FRONT AND SWEEP ACROSS THE AREA WED MORNING. NOT SURE IF EVERYTHING WILL COME TOGETHER FOR A POTENT SEVERE WEATHER OUTBREAK...BUT THE DEEP MOISTURE AND DIVERGENCE ALOFT SHOULD RESULT IN A HIGH COVERAGE OF RAINFALL. THE MAGNITUDE OF LOW LEVEL SHEAR SHOULD SUPPORT ROTATING STORMS BUT THE AMOUNT OF NIGHTTIME INSTABILITY IS TYPICALLY PROBLEMATICAL. CONVECTION LATE TUE MAY HAVE AN ENHANCED HAIL THREAT AS THERE SHOULD INITIALLY BE A DRY MID LEVEL LAYER. LOW LEVEL FLOW IS PROGGED TO VEER AFTER MIDNIGHT BUT THIS IS DEPENDENT ON POSITION/TIMING/STRENGTH OF SURFACE LOW FORMATION...SO CANNOT RULE OUT A THREAT FOR TORNADOES. && .MLB WATCHES/WARNINGS/ADVISORIES... AM...SMALL CRAFT ADVISORY FROM TUE NIGHT TO EARLY THU MORNING FOR THE WATERS 20-60 NM OFFSHORE BETWEEN FLAGLER BEACH AND JUPITER INLET. && $$ SHORT TERM/AVIATION...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 841 PM CST TUE FEB 12 2008 .DISCUSSION... ISSUED 840 PM CST TUE FEB 12 2008 CLOUDS CLEARING OUT QUICKER THAN EARLIER ANTICIPATED THIS EVENING WHICH HAS RESULTED IN A QUICK DROP IN TEMPS...ESP ACRS THE NW. UPPER TROF CLEARLY SEEN ON WATER VAPOR ACRS THE CNTRL U.S. WL TRACK EAST TNT AND TAKE THE WEATHER SYSTEM OVER THE OHIO VALLEY WELL TO OUR EAST. HIGH PRESSURE OVER THE MISSOURI VALLEY WL TAKE HOLD OF OUR WX WITH CLEARING SKIES AND VERY COLD TEMPS. PREVIOUS FCST HAD OVERNIGHT LOWS NEAR ZERO IN THE NW AND IN THE SINGLE DIGITS ACRS THE CNTRL WITH LOW TO MID TEENS IN THE SOUTHEAST. BASED ON UPSTREAM TEMPS AND DEW POINTS AND HI RES RUC AND NMM4 2 METER TEMPS FOR THE OVERNIGHT HOURS...WL HAVE TO MAKE SOME MINOR MODIFICATIONS TO OVERNIGHT LOWS...AS WELL AS SOME ADJUSTMENTS TO THE SKY GRIDS. SMITH && .AVIATION... ISSUED 545 PM CST TUE FEB 12 2008 MAIN ISSUE THIS PERIOD WILL BE TIMING OF STRATOCU DECK OUT OF THE TAF SITES THIS EVENING ALONG WITH THE SCATTERED SNOW SHOWERS. UPPER TROF SHIFTING EWD ACRS THE MIDWEST LATE THIS AFTN AND EVENING SHOULD TAKE THE LAST ROUND OF FLURRIES/SNOW SHOWERS WITH IT. BASED ON SATELLITE TRENDS...THE PIA AND SPI TAF SITES SHOULD SEE CIGS IMPROVE BETWEEN 02Z AND 04Z...DECATUR JUST BEFORE MIDNIGHT. WITH LOW LVL CYCLONIC FLOW CONTINUING OVERNIGHT...IT APPEARS THE BMI AND CMI TAF SITES WILL BE A BIT SLOWER TO CLEAR OUT...MORE IN THE 07Z-09Z TIME FRAME. SFC FLOW WL REMAIN FROM A 290-320 DIRECTION THRU THE PERIOD WITH WINDS BACKING MORE INTO A WESTERLY DIRECTION TOWARDS THE END OF FORECAST PERIOD. SMITH && .PREV DISCUSSION... ISSUED 244 PM CST TUE FEB 12 2008 INITIAL ISSUES WILL BE LINGERING PRECIP FROM THIS STORM SYSTEM...THEN HOW COLD TO GO FOR LOWS TONIGHT. THE NEXT SYSTEM OF INTEREST WILL BE ON THURSDAY NIGHT...AS A COLD FRONT GETS PULLED ACROSS ILLINOIS DUE TO A POTENT SYSTEM MOVING ACROSS MN AND WI. OUR AREA WILL SEE A QUICK SHOT OF SNOW...AND MAYBE A MIX OF RAIN AND SNOW SOUTHEAST OF I-72. THE LONG RANGE IS BEING HIGHLIGHTED BY A STRONG STORM EXPECTED TO LIFT BY TO OUR EAST ON SUNDAY AND SUNDAY NIGHT. THE LATEST RUNS HAVE NOW PUSHED THE STORM FAR ENOUGH EAST TO KEEP PRECIP OUT OF ILLINOIS...BUT THE TRACK WILL LIKELY BE ADJUSTED FARTHER WEST AS THE DAYS GO BY. SHORT TERM...TONIGHT THROUGH THURSDAY. DEFORMATION ZONE SNOWS WILL LIKELY CLIP OUR NORTHERN CWA THIS EVENING...WHILE THE EASTERN CWA DEALS WITH LIGHT SNOW CLOSER TO THE JET MAX TO OUR EAST. THE FREEZING DRIZZLE HAS CHANGED OVER TO ALL SNOW AS ICE CRYSTALS ALOFT HAVE RETURNED. I ADDED LIGHT SNOW OR FLURRIES TO MOST OF THE CWA FOR THIS EVENING...WITH HIGHER PRECIP CHANCES ACROSS THE NORTH. NOT EXPECTING MUCH MORE THAN A DUSTING OF ADDITIONAL SNOW FROM THE REST OF THIS SYSTEM. LOWS TONIGHT WILL BE A TOUGH CALL...PRIMARILY DUE TO WHERE THE CLOUDS CLEAR OUT...AND FIGURING OUT HOW ANY SNOW ACCUMULATION WILL AFFECT THE TEMPS. IN GENERAL...WILL BE TRENDING SLIGHTLY COLDER THAN GUIDANCE...ESPECIALLY IN OUR WESTERN CWA WHERE WE HAVE A BETTER CHANCE TO CLEAR OUT. NORTHWEST FLOW HAS INCREASING ACROSS THE ENTIRE CWA...WHICH MAY WORK TO PUSH ADDITIONAL CLOUDS INTO OUR AREA...BASED ON SATELLITE TRENDS. HOWEVER...ENOUGH DRY AIR ALOFT SHOULD MIX OUT CLOUDS AT LEAST A LITTLE IN OUR WEST. SOME CLEARING IS APPROACHING WESTERN ILL ALREADY...AND THE SURFACE LOW IS ALMOST INTO OHIO. WEDNESDAY SHOULD SEE DECREASING CLOUDS...AS THE SURFACE RIDGE AXIS PASSES OVER ILLINOIS. H85 TEMPS WILL BE ON A STEADY RISE ALL DAY...BUT HIGHS WILL REMAIN BELOW NORMAL DUE TO THE COLD START. THURSDAY WILL BE NOTICEABLY WARMER...WITH HIGHS CLIMBING INTO THE LOWER 40S IN MOST LOCATIONS. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. A STORM SYSTEM WILL DROP A BAND OF HEAVY SNOWS ON MN AND WI ON THURSDAY AND THURSDAY NIGHT...WHILE A COLD FRONT PUSHES ACROSS IL THUR NIGHT. OUR AREA WILL BE FAR ENOUGH SOUTH OF THE SURFACE LOW AND H85 LOW...THAT WE SHOULD BE SPARED THE HEAVIER SNOWS. OUR AREA NW OF THE IL RIVER MAY GET A HALF INTO TO ONE INCH...BUT ELSEWHERE WILL MOST LIKELY SEE SCATTERED SNOW SHOWERS...OR EVEN SOME RAIN SHOWERS SOUTHEAST OF I-72. ANOTHER SHOT OF ARCTIC AIR BEHIND THAT FRONT WILL DROP TEMPS ON FRIDAY AND FRIDAY NIGHT WELL BELOW NORMAL. TEMPS WILL REBOUND FOR SATURDAY AS HIGHS RETURN TO THE 30S. SUNDAY REMAINS A QUESTION MARK AS THE MODELS TRY TO DETERMINE THE PATH OF A SOUTHERN STREAM STORM AND HOW IT WILL PHASE WITH A NORTHERN STREAM SYSTEM JUST TO OUR EAST. FOR NOW...I PULLED BACK ON THE POPS TO SLIGHT CHANCE AND ONLY HAVE POPS IN THE EAST NEAR THE STORM. PAST HISTORY OF HOW THE MODELS HANDLE STORMS THAT FAR INTO THE FUTURE INDICATES WE SHOULD SEE THE STORM TRACK RESOLVE CLOSER TO THE COLDER AIR EVENTUALLY. HOW FAR WEST IT ENDS UP WILL PLAY A HUGE ROLL IN HOW MUCH WINTRY WEATHER AFFECTS OUR SE CWA. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1137 AM CST TUE FEB 12 2008 .DISCUSSION... ISSUED 1018 AM CST TUE FEB 12 2008 FORECAST HAS ALREADY BEEN UPDATED FOR THIS MORNINGS FREEZING DRIZZLE ACROSS THE AREA. ILX 12Z RAOB SOUNDING SHOWS SIGNIFICANT DRY LAYER AT THE MIDLEVELS...AND DRYNESS ALOFT...NEGATING CHANCE FOR ICE CRYSTAL FORMATION. AS A RESULT... LOW LEVEL MOISTURE COMING OUT OF THE CLOUDS AS MOSTLY FREEZING DRIZZLE. GLAZING ON ROADS WHERE THE DRIZZLE HAS BEEN GOING ON A LITTLE LONGER...ALONG AND SOUTHEAST OF INTERSTATE 72. OTHER THAN THAT...ADDITIONAL SNOW ACCUMULATION AS THE COLD MOISTURE WORKS INTO THE REGION FROM THE NW ...SHOULD REMAIN NEGLIGIBLE...LESS THAN AN INCH FOR MOST LOCATIONS NORTH OF INTERSTATE 72. FORECAST ALREADY ISSUED. && .AVIATION... ISSUED 1128 AM CST TUE FEB 12 2008 PLENTY OF LOW CLOUDS ACROSS THE AREA PRODUCING SOME FREEZING DRIZZLE IN THE SOUTHEAST...AND LIGHT SNOW FLURRIES IN AREAS WHERE COLD AIR IS WORKING ITS WAY INTO THE REGION. SYSTEM MOVING A BIT MORE SLOWLY THAN PREVIOUSLY ADVERTISED. LOOKING AT 11-3.9 SATELLITE IMAGERY...A SIGNIFICANT DIVISION OF CLOUDS OUT OVER IA MAKING ITS WAY TO THE TAF SITES. AT THIS POINT... THE EDGE OF THE CLOUDS IS GETTING MORE DIFFUSE...SO WILL GENERALLY MAINTAIN THE TREND OF LOW CLOUDS THROUGH TOMORROW MORNING. KEEPING FLURRIES AT LEAST INTO THE EVENING HOURS. NOT UNTIL TOMORROW MID MORNING TO SCATTER OUT THE CLOUDS A BIT AS THE WINDS BACK TO THE WEST. MAY ADD PRECIP LATER THIS EVENING IF THE LOW LEVEL MOISTURE HOLDS OUT...AND MAY END UP KILLING THE LOW CLOUDS EARLIER IF THE DRY AIR WINS. MODELS ARE SPLIT DOWN THE MIDDLE AND NOT MUCH ASSISTANCE AT THIS POINT...SO MUCH OF THIS FORECAST IS PERSISTENCE. HJS && .PREV DISCUSSION... ISSUED 345 AM CST TUE FEB 12 2008 SHORT TERM...TODAY THROUGH THURSDAY. EARLY MORNING SFC ANALYSIS HAD LOW PRESSURE CENTERED OVER EASTERN TENNESSEE...WITH ATTENDANT COLD FRONT TRAILING BACK TO A MESO LOW OVER SOUTHEASTERN OKLAHOMA...AND NEARLY STATIONARY WARM FRONT LAID OUT JUST SOUTH OF THE OHIO RIVER. BAND OF PRECIPITATION CERTAINLY TURNED OUT TO BE SHARPLY DEFINED INVOF THE WARM FRONT! LITTLE MORE THAN FREEZING DRIZZLE HAS OCCURRED ACROSS OUR FAR SOUTHERN COUNTIES... BUT ONE DOES NOT HAVE TO TRAVEL TOO FAR SOUTH OF OUR CWA TO ENCOUNTER AN AREA THAT RECEIVED SOME PRETTY MAJOR ICING OVERNIGHT. MEANWHILE... APPROACHING SHORTWAVE TROUGH IS RUNNING A LITTLE BEHIND SCHEDULE... AND ALTHOUGH IT LOOKS IMPRESSIVE ON WATER VAPOR IMAGERY... UPSTREAM OBS AND RADAR IMAGERY SUGGESTS JUST VERY LIGHT SNOW IS FALLING ACROSS IOWA JUST AHEAD OF THE VORT MAX. SFC VISBYS RANGE FROM 3-5SM... AND THE HIGHER REFLECTIVITIES ON RADAR REMAIN ALONG AND NORTH OF THE ARCTIC FRONT WHICH IS DRAPED JUST NORTH OF I-80. THE ONE CONCERN ALL NIGHT HAS BEEN WHETHER OR NOT THE APPROACHING SHORTWAVE WOULD HELP TO SCOOP UP BETTER MOISTURE INTO OUR SOUTHEASTERN COUNTIES THIS MORNING AS MID-LEVEL WINDS START TO BACK. SO FAR THIS HAS NOT HAPPENED. ENHANCED AREA OF PRECIP ALONG THE SOUTHERN FRONTAL BOUNDARY ASSOCIATED WITH THE APPROACHING TROUGH HAS DEVELOPED INTO A RATHER NICE LINE OF CONVECTION WHICH LOOKS POISED TO CONTINUE TO MATCH DUE EAST. CIRRUS BLOW OFF FROM THIS CONVECTION IS BEING PULLED UP INTO SOUTHERN MISSOURI... AND THIS MAY BE HELPING TO PRODUCE SOME FREEZING DRIZZLE AT SGF THROUGH A SEEDER-FEEDER MECHANISM. SFC DEWPOINTS ARE ALSO MUCH HIGHER DOWN THERE. NAM/RUC SOUNDINGS ACROSS OUR CWA INDICATE LOTS OF MID-LEVEL DRY AIR AND A LACK OF ICE CRYSTALS IN THE SATURATED COLUMN EXCEPT ACROSS THE FAR NORTH. HOWEVER... AS LONG AS DEWPOINTS REMAIN IN THE UPPER SINGLE DIGITS AND LOWER TEENS... FZDZ IS NOT LIKELY TO BE MUCH OF A CONCERN NORTH OF I-70. SO FOR NORTH OF I-70 TODAY... EXPECT JUST SOME SCATTERED SNOW SHOWERS OR FLURRIES AS THE TROUGH SWINGS THROUGH... WITH MINIMAL ACCUMULATION AMOUNTS... PERHAPS A DUSTING AT BEST ALONG/NORTH OF I-72. ALTHOUGH SOUNDINGS SUGGEST LACK OF ICE CRYSTALS NOW ALONG THE I-72 CORRIDOR... COOLING ALOFT AS TROUGH APPROACHES SHOULD ALSO HELP MITIGATE FZDZ THREAT EARLIER THIS MORNING. SOUTH OF I-70... WITH HIGHER DEWPOINTS AND LACK OF ICE CRYSTALS GIVEN DRY MID-LEVELS... PERIODS OF FZDZ COULD CONTINUE THROUGH ABOUT NOON. UPSTREAM VWP AND PROFILERS SUGGEST LOW LEVEL WINDS IN THE SATURATED LAYER WILL BE DECREASING IN TIME... WHICH RESULTS IN LESSENING CHANCES FOR DRIZZLE AS THERE WILL BE LESS DROPLET COLLISIONS IN THE INCREASINGLY LESS TURBULENT ENVIRONMENT. BY 18Z... COOLING ALOFT SHOULD MITIGATE FZDZ THREAT... WITH LIGHT SNOW SHOWERS OR JUST FLURRIES POSSIBLE. ROAD REPORTS SUGGEST SOME LIGHT GLAZING HAS OCCURRED IN THE ADVISORY AREA THIS MORNING...SO WE HAVE DECIDED TO KEEP THE REMAINING ADVISORY GOING THROUGH THE MORNING COMMUTE... AS SOME ICY SPOTS LIKELY EXIST...ESPECIALLY ON BACK ROADS. QUIET WX TO REIGN TONIGHT AND WEDNESDAY. APPROACHING COLD FRONT WILL PASS THROUGH THE AREA THURSDAY NIGHT... WITH WARMER AIR ADVECTING INTO THE AREA THURSDAY AFTERNOON. TEMPS IN THE MID-40S LIKELY ACROSS MUCH OF THE WESTERN 2/3RDS OF THE CWA THU. COLDER AIR WILL FILTER IN BEHIND THE FRONT. SYSTEM STILL LOOKS MOISTURE STARVED... AND THE BEST DYNAMICS WILL BE TO OUR NORTH... SO STILL KEPT PRECIP CHANCES FAIRLY LOW... ESPECIALLY SOUTHEAST OF THE ILLINOIS RIVER. LONG TERM...FRIDAY AND SATURDAY. MODELS COMING INTO BETTER AGREEMENT ON OVERALL PATTERN THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. FRI AND SATURDAY LIKELY TO REMAIN DRY... AS CUTOFF LOW DEVELOPS OVER THE DESERT SOUTHWEST. TIMING AND PATH OF THIS SYSTEM PULLING OUT WILL BE CRITICAL DURING THE SUN-MON TIME FRAME. GENERALLY PREFER THE SLOWER SOLUTIONS WITH CUTOFFS. GFS HAS TRENDED SLOWER... CLOSER TO THE ECMWF/UKMET SOLUTION. MODELS STILL HAVING SOME DISAGREEMENT WITH RESPECT TO THE STRENGTH/AMPLITUDE OF THE APPROACHING KICKER TROUGH... AS WELL AS HOW FAR SOUTH INTO MEXICO THE CUTOFF DROPS. A FAIRLY SIGNIFICANT STORM IS LIKELY TO AFFECT THE SOUTHERN PLAINS WHEN THIS SYSTEM FINALLY KICKS OUT. MODELS STILL KEEP THE BULK OF THE PRECIP ALONG AND SOUTH OF THE OHIO RIVER... BUT THIS IS STILL A LONG WAYS OUT... AND ALL WINTER THE MODELS HAVE BEEN TRACKING THESE SYSTEMS TOO FAR SOUTH AND EAST. EITHER WAY... SLOWER SOLUTION MEANS THIS HAS NO BEARING ON THE DAY 4-5 FORECAST. HARDIMAN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 547 AM CST TUE FEB 12 2008 .DISCUSSION... ISSUED 345 AM CST TUE FEB 12 2008 SHORT TERM...TODAY THROUGH THURSDAY. EARLY MORNING SFC ANALYSIS HAD LOW PRESSURE CENTERED OVER EASTERN TENNESSEE...WITH ATTENDANT COLD FRONT TRAILING BACK TO A MESO LOW OVER SOUTHEASTERN OKLAHOMA...AND NEARLY STATIONARY WARM FRONT LAID OUT JUST SOUTH OF THE OHIO RIVER. BAND OF PRECIPITATION CERTAINLY TURNED OUT TO BE SHARPLY DEFINED INVOF THE WARM FRONT! LITTLE MORE THAN FREEZING DRIZZLE HAS OCCURRED ACROSS OUR FAR SOUTHERN COUNTIES... BUT ONE DOES NOT HAVE TO TRAVEL TOO FAR SOUTH OF OUR CWA TO ENCOUNTER AN AREA THAT RECEIVED SOME PRETTY MAJOR ICING OVERNIGHT. MEANWHILE... APPROACHING SHORTWAVE TROUGH IS RUNNING A LITTLE BEHIND SCHEDULE... AND ALTHOUGH IT LOOKS IMPRESSIVE ON WATER VAPOR IMAGERY... UPSTREAM OBS AND RADAR IMAGERY SUGGESTS JUST VERY LIGHT SNOW IS FALLING ACROSS IOWA JUST AHEAD OF THE VORT MAX. SFC VISBYS RANGE FROM 3-5SM... AND THE HIGHER REFLECTIVITIES ON RADAR REMAIN ALONG AND NORTH OF THE ARCTIC FRONT WHICH IS DRAPED JUST NORTH OF I-80. THE ONE CONCERN ALL NIGHT HAS BEEN WHETHER OR NOT THE APPROACHING SHORTWAVE WOULD HELP TO SCOOP UP BETTER MOISTURE INTO OUR SOUTHEASTERN COUNTIES THIS MORNING AS MID-LEVEL WINDS START TO BACK. SO FAR THIS HAS NOT HAPPENED. ENHANCED AREA OF PRECIP ALONG THE SOUTHERN FRONTAL BOUNDARY ASSOCIATED WITH THE APPROACHING TROUGH HAS DEVELOPED INTO A RATHER NICE LINE OF CONVECTION WHICH LOOKS POISED TO CONTINUE TO MATCH DUE EAST. CIRRUS BLOW OFF FROM THIS CONVECTION IS BEING PULLED UP INTO SOUTHERN MISSOURI... AND THIS MAY BE HELPING TO PRODUCE SOME FREEZING DRIZZLE AT SGF THROUGH A SEEDER-FEEDER MECHANISM. SFC DEWPOINTS ARE ALSO MUCH HIGHER DOWN THERE. NAM/RUC SOUNDINGS ACROSS OUR CWA INDICATE LOTS OF MID-LEVEL DRY AIR AND A LACK OF ICE CRYSTALS IN THE SATURATED COLUMN EXCEPT ACROSS THE FAR NORTH. HOWEVER... AS LONG AS DEWPOINTS REMAIN IN THE UPPER SINGLE DIGITS AND LOWER TEENS... FZDZ IS NOT LIKELY TO BE MUCH OF A CONCERN NORTH OF I-70. SO FOR NORTH OF I-70 TODAY... EXPECT JUST SOME SCATTERED SNOW SHOWERS OR FLURRIES AS THE TROUGH SWINGS THROUGH... WITH MINIMAL ACCUMULATION AMOUNTS... PERHAPS A DUSTING AT BEST ALONG/NORTH OF I-72. ALTHOUGH SOUNDINGS SUGGEST LACK OF ICE CRYSTALS NOW ALONG THE I-72 CORRIDOR... COOLING ALOFT AS TROUGH APPROACHES SHOULD ALSO HELP MITIGATE FZDZ THREAT EARLIER THIS MORNING. SOUTH OF I-70... WITH HIGHER DEWPOINTS AND LACK OF ICE CRYSTALS GIVEN DRY MID-LEVELS... PERIODS OF FZDZ COULD CONTINUE THROUGH ABOUT NOON. UPSTREAM VWP AND PROFILERS SUGGEST LOW LEVEL WINDS IN THE SATURATED LAYER WILL BE DECREASING IN TIME... WHICH RESULTS IN LESSENING CHANCES FOR DRIZZLE AS THERE WILL BE LESS DROPLET COLLISIONS IN THE INCREASINGLY LESS TURBULENT ENVIRONMENT. BY 18Z... COOLING ALOFT SHOULD MITIGATE FZDZ THREAT... WITH LIGHT SNOW SHOWERS OR JUST FLURRIES POSSIBLE. ROAD REPORTS SUGGEST SOME LIGHT GLAZING HAS OCCURRED IN THE ADVISORY AREA THIS MORNING...SO WE HAVE DECIDED TO KEEP THE REMAINING ADVISORY GOING THROUGH THE MORNING COMMUTE... AS SOME ICY SPOTS LIKELY EXIST...ESPECIALLY ON BACK ROADS. QUIET WX TO REIGN TONIGHT AND WEDNESDAY. APPROACHING COLD FRONT WILL PASS THROUGH THE AREA THURSDAY NIGHT... WITH WARMER AIR ADVECTING INTO THE AREA THURSDAY AFTERNOON. TEMPS IN THE MID-40S LIKELY ACROSS MUCH OF THE WESTERN 2/3RDS OF THE CWA THU. COLDER AIR WILL FILTER IN BEHIND THE FRONT. SYSTEM STILL LOOKS MOISTURE STARVED... AND THE BEST DYNAMICS WILL BE TO OUR NORTH... SO STILL KEPT PRECIP CHANCES FAIRLY LOW... ESPECIALLY SOUTHEAST OF THE ILLINOIS RIVER. LONG TERM...FRIDAY AND SATURDAY. MODELS COMING INTO BETTER AGREEMENT ON OVERALL PATTERN THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK. FRI AND SATURDAY LIKELY TO REMAIN DRY... AS CUTOFF LOW DEVELOPS OVER THE DESERT SOUTHWEST. TIMING AND PATH OF THIS SYSTEM PULLING OUT WILL BE CRITICAL DURING THE SUN-MON TIME FRAME. GENERALLY PREFER THE SLOWER SOLUTIONS WITH CUTOFFS. GFS HAS TRENDED SLOWER... CLOSER TO THE ECMWF/UKMET SOLUTION. MODELS STILL HAVING SOME DISAGREEMENT WITH RESPECT TO THE STRENGTH/AMPLITUDE OF THE APPROACHING KICKER TROUGH... AS WELL AS HOW FAR SOUTH INTO MEXICO THE CUTOFF DROPS. A FAIRLY SIGNIFICANT STORM IS LIKELY TO AFFECT THE SOUTHERN PLAINS WHEN THIS SYSTEM FINALLY KICKS OUT. MODELS STILL KEEP THE BULK OF THE PRECIP ALONG AND SOUTH OF THE OHIO RIVER... BUT THIS IS STILL A LONG WAYS OUT... AND ALL WINTER THE MODELS HAVE BEEN TRACKING THESE SYSTEMS TOO FAR SOUTH AND EAST. EITHER WAY... SLOWER SOLUTION MEANS THIS HAS NO BEARING ON THE DAY 4-5 FORECAST. HARDIMAN && .AVIATION... ISSUED 547 AM CST TUE FEB 12 2008 MVFR CIGS BETWEEN 1KFT AND 2.5KFT WILL BE SEEN AT BMI AND PIA ALL DAY AS WINDS START NORTHEAST AND SWITCH TO THE NORTHWEST BY TONIGHT. IFR CIGS JUST UNDER 1KFT WILL BE AT SPI...DEC AND CMI THROUGH THIS MORNING...THEN RISE TO MVFR (BETWEEN 1KFT AND 1.5KFT) AROUND 19-20Z...THEN GRADUALLY RISE AGAIN TO AROUND 2.5KFT AFTER MIDNIGHT. LIKE PIA AND BMI...WINDS WILL START AS NORTHEAST AND THEN GRADUALLY TRANSITION THROUGHOUT THE DAY AND BECOME NORTHWEST BY TONIGHT. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR ILZ067- 068-071>073. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1142 PM CST MON FEB 11 2008 .UPDATE... ISSUED 1142 PM CST MON FEB 11 2008 LARGE AREA OF MIXED PRECIPITATION IS ON PRETTY MUCH A STRAIGHT LINE TO MOVE ACROSS SOUTHEASTERN ILLINOIS TO THE SOUTHEAST OF A LINE FROM LOUISVILLE TO ROBINSON. EFFINGHAM...CUMBERLAND...AND CLARK COUNTIES WILL LIKELY NOT GET ADVISORY LEVEL ACCUMULATIONS OF SNOW OR SLEET. WILL THEREFORE CANCEL THESE COUNTIES FROM THE ADVISORY. KLWV HAS RECENTLY REPORTED FREEZING RAIN...AND THE 04Z RUC ANALYSIS SOUNDING SIMULATION SHOWS SOMEWHAT OF A WARM NOSE IN THE LOWER LAYERS. SO WILL ADD A MENTION OF FREEZING RAIN IN THE ADVISORY AREA. 04 && .AVIATION... ISSUED 1116 PM CST MON FEB 11 2008 MVFR CLOUDS HAVE MOVED INTO THE SPI-DEC-CMI AREAS THIS EVENING. LIGHT PRECIPITATION IN THE FORM OF LIGHT SNOW AND LIGHT FREEZING DRIZZLE WILL MOVE THROUGH IN A TEMPO FASHION...POSSIBLY A LITTLE MORE WIDESPREAD 10Z-14Z TUE. INITIAL VFR CONDITIONS PIA-BMI WILL ALSO BECOME MVFR WITH TIME WITH OCCASIONAL LIGHT SNOW. EXPECT PRECIPITATION TO END BY 18Z TUE IN THE SPI-DEC-CMI CORRIDOR. PIA-BMI WILL PROBABLY SEE LIGHT SNOW END BY 20Z. EVEN AFTER THE LIGHT SNOW ENDS...WILL SEE MVFR CLOUDS CONTINUE THROUGH 06Z WED. 04 && .PREV DISCUSSION... ISSUED 833 PM CST MON FEB 11 2008 WILL BE MAKING ADJUSTMENTS IN THE OVERALL FORECAST SOON. CENTRAL ILLINOIS IS CAUGHT BETWEEN TWO SYSTEMS THIS EVENING. THE NORTHERN SHEAR ZONE/ISENTROPIC LIFT REGION HAS BEEN NORTH OF OUR COUNTIES THIS AFTERNOON AND EVENING...AND BELIEVE THIS TREND WILL CONTINUE. UPSTREAM VORT MAX OVER NEBRASKA WILL MOVE EAST OVERNIGHT AND THIS MAY INCREASE SNOWFALL IN THE NORTH...BUT ACCUMULATIONS SHOULD BE LIGHT AS THE WAVE WILL BE MOVING INTO CONFLUENT FLOW ALOFT AND THE MOISTURE WILL BE MUCH MORE LIMITED THAN AREAS TO THE SOUTH. WILL THEREFORE HAVE CHANCE POPS BEFORE MIDNIGHT THEN LOW-END LIKELY POPS AFTER MIDNIGHT FOR AN INCH OR TWO ACCUMULATION AT BEST. FURTHER SOUTH...STRONG BAROCLINIC ZONE EXTENDS FROM SOUTHERN MISSOURI INTO EXTREME SOUTHERN ILLINOIS THEN JUST SOUTH OF THE OHIO RIVER. INCREASING LOW LEVEL JET FROM TEXAS INTO ARKANSAS AHEAD OF A SOUTHERN STREAM SHORTWAVE HAS CAUSED A DRAMATIC INCREASE IN CONVECTION TO THE NORTH OF THE BOUNDARY...MOSTLY IN THE FORM OF THUNDERSTORMS WITH SLEET AND FREEZING RAIN. THIS ACTIVITY LOOKS LIKE IT WILL MOVE ACROSS OUR SOUTHEASTERN COUNTIES MAINLY TO THE SOUTH OF INTERSTATE 70 LATER TONIGHT. BY THE TIME THE PRECIPITATION MOVES NORTHEASTWARD AS FAR NORTH AS THE FLORA AREA...IT SHOULD BE MOSTLY SNOW AND SLEET. ADVISORY LEVEL ACCUMULATIONS OF SLEET AND SNOW STILL APPEAR LIKELY...SO WILL KEEP THE WINTER WEATHER ADVISORY GOING WITH TOTAL ACCUMULATIONS OF 3 PERHAPS 4 INCHES. FURTHER NORTH...AN EXTENSIVE AREA OF DRY AIR WAS SAMPLED BY THE 00Z LINCOLN SOUNDING EXTENDING FROM THE SURFACE TO ABOUT 4KFT. RICHER MOISTURE THEN EXTENDS UPWARD BUT ONLY MAKES IT TO 10KFT. SINCE THERE IS LITTLE MOISTURE IN THE PREFERRED DENDRITIC ICE GROWTH ZONE BETWEEN -10C AND -20C /12K-16K FT/ EXPECT THAT MOST OF THE PRECIPITATION WILL BE SPOTTY AND IN THE FORM OF LIGHT SNOW AND LIGHT FREEZING DRIZZLE. THE PROSPECTS FOR SIGNIFICANT ACCUMULATIONS IN THE CENTRAL COUNTIES THEREFORE APPEARS SLIM...SO WILL SHAVE A TIER OF COUNTIES FROM THE NORTH END OF THE WINTER WEATHER ADVISORY AREA /I.E. SHELBY...COLES AND EDGAR/. ACCUMULATIONS ACROSS THE MIDDLE PART OF THE FORECAST AREA WILL PROBABLY BE LESS THAN AN INCH...IF THAT MUCH. 04 && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR ILZ067-068-071>073. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE QUAD CITIES IA IL 903 PM CST TUE FEB 12 2008 .UPDATE... GRIDS/ZFP RECENTLY UPDATED TO DECREASE AMOUNT OF CLOUDS OVER THE AREA THIS EVENING AND TO REMOVE ANY SNOW WORDING WITH THE LAST OF THE -SN ALMOST OUT OF THE CWFA. TEMP FORECAST FOR THE REST OF TONIGHT WILL BE TRICKY. WITH THE CLEARING THAT HAS TAKEN PLACE SO FAR THIS EVENING TEMPS HAVE DROPPED RAPIDLY IN SOME AREAS. KDVN WAS DOWN TO -4 AS OF 03Z AND KMXO AND KCWI WERE AROUND ZERO. COMPLICATING THE TEMPERATURE FORECAST WAS A NARROW BAND OF AC FROM JUST WEST OF KMUT NORTH THE KIOW KCID AND KVTI WHICH WAS KEEPING TEMPS FROM COOLING MUCH. RUC H800 RH PROGS HOLD THIS RH OVER ERN IA NRN IL MOST OF THE EVENING BUT SHOW IT EAST OF THE AREA AROUND 06Z. BASED ON THIS FEEL THE AC SHOULD PUSH EAST BY 06Z LEAVING CLEAR SKIES OVER THE ENTIRE CWA THE REST OF THE NIGHT. THE CLEAR SKIES COMBINED WITH THE SURFACE HIGH BUILDING EAST TOWARD THE AREA AND FRESH SNOW COVER SHOULD ALLOW FOR A DECENT TEMP DROP LATE TONIGHT...SO HAVE TWEAKED MIN TEMPS DOWN A FEW DEGREES. ...DLF... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ DLF ia AREA FORECAST DISCUSSION...UPDATE... NATIONAL WEATHER SERVICE QUAD CITIES IA IL 1030 AM CST TUE FEB 12 2008 .UPDATE... RESPECTABLE DEFORMATION ZONE SITTING ACROSS EASTERN IOWA THIS MORNING PRODUCING ACCUMULATING SNOW. SOME REPORTS SO FAR INDICATE ABOUT AN INCH OF NEW SNOWFALL. HAVE UPDATED CURRENT FCST TO BEEF UP THE MENTION OF SNOW. 15Z RUC SHOWS RESPECTABLE VORT MAX HELPING TO MAINTAIN THE SNOWFALL AND THIS WILL CONTINUE INTO THE AFTERNOON HOURS. BEST GUESS RIGHT NOW IS NEW SNOW OF 1-2 INCHES DURING THE DAYLIGHT HOURS. PRECIP SHOULD END RATHER ABRUPTLY FROM WEST TO EAST FROM ABOUT MID AFTERNOON ON. SINCE SNOW WILL HANG AROUND A LITTLE LONGER THAN THOUGHT...HAVE ALSO LOWERED MAX TEMPS FOR TODAY AS WELL. ...08... /PREVIOUS DISCUSSION/ .SYNOPSIS... SIGNIFICANT SNOWS HAVE MOVED EAST AND NORTHEAST OF FORECAST AREA LEAVING 1 TO 4 INCH SNOW TOTALS ALONG AND NORTH OF I-80 CORRIDOR WITH TRACE UP TO AN INCH SOUTH. SURFACE AND UPPER ANALYSIS SHOWS WEAK SUBSIDENCE WITH LOTS OF LOW LEVEL MOISTURE WITH LOCAL TOOLS SUGGESTING MOST TO ALL REGION TO REMAIN CLOUDY WITH PATCHY FLURRIES AND JUST A FEW AREAS OF LIGHT SNOW NEXT 6 TO 12 HOURS. BECAUSE OF THIS...HAVE CANCELLED SNOW ADVISORY OVER NORTH 1/3 OF FORECAST AREA. EXTENDED WEAK DEFORMATION ZONE BACK INTO EASTERN NEBRASKA MAY ALLOW SOME LINGERING FLURRIES AND LIGHT SNOW TO PERSIST INTO NE SECTIONS OF FORECAST AREA INTO MID TO LATE AFTERNOON. SURFACE ANALYSIS INDICATES AREA TEMPERATURES REMAIN ON LOW END OF GUIDANCE DUE TO NEGATIVE FEEDBACK OF DEEP SNOW COVER OVER NORTHWESTERN 2/3 OF AREA. && .SHORT TERM...TODAY AND TONIGHT... TODAY...REDUCED POPS WITH MORNING CHANCE OF LIGHT SNOW AND OCCASIONAL FLURRIES BECOMING SCATTERED PM FLURRIES...ENDING FROM SW TO NE AS LAST SEGMENTS OF WEAK DEFORMATION ZONE MOVES EAST. KEPT MAX TEMPERATURES IN UPPER TEENS NORTH TO LOWER 20S SOUTH WITH CLOUDS AND NORTH WIND OF 5 TO 15 MPH SUPPORTS ARCTIC AIR TO CONTINUE TO SLOWLY MODIFY UNDER DEEP SNOW PACK. AREA MOS GUIDANCE REMAINS HAVING DIFFICULTY WITH THIS BL NEGATIVE FEEDBACK...THUS SUPPORTING USING MAINLY PERSISTENCE TREND. TONIGHT...SKIES WITH WEAK TO MODERATE SUBSIDENCE AS WEAK SURFACE AND UPPER RIDGE TO ALLOW AT LEAST PARTIAL CLEARING AND ADD LIGHT WINDS...GOOD RADIATIVE COOLING SUPPORTS AREA TEMPERATURES TO CRASH. KEPT MINS 3-5 DEGREES BELOW GUIDANCE BUT IF PROGGED CONDITIONS VERIFY...AREAS AFTER MIDNIGHT TO SEE TEMPERATURES TO CRASH PROBABLY WELL BELOW ZERO WITH INTENSE INVERSION IN NORTH 2/3 SUPPORTING AREAS OF FREEZING FOG AND POSSIBLE HOAR FROST FORMATION ENHANCED BY OUR FRESH FINE...POWDERY SNOW. LEFT FOG OUT OF FORECAST ATTM AND PASS THIS ISSUE TO DAY SHIFT TO ASSESS FURTHER. .LONG TERM...WEDNESDAY THROUGH MONDAY... MAIN FOCUS IS TEMPERATURES AND PRECIPITATION CHANCES AS NEXT COLD FRONT PUSHES THROUGH ON THURSDAY. AREA WILL BE UNDER SURFACE AND MID FLAT MID LEVEL RIDGE WED. SUBSIDENCE INVERSION AND DEEP SNOW COVER WILL PREVENT MUCH TEMPERATURE RECOVERY AFTER COLD START...EVEN WITH FEB SUNSHINE. WILL SEE SOME WEAK WAA SWLY FLOW LATE IN THE DAY. HAVE CONTINUED TO TREND TOWARD COLDEST MET GUIDANCE WITH LOWER TO MID 20S OVER ALL BUT SNOW-FREE NE MO AND W CENTRAL IL...WHERE WE SHOULD SEE LOWER 30S. WED NIGHT THROUGH THU...00Z MODELS HAVE COME INTO BETTER AGREEMENT WITH MORE PROGRESSIVE AND LESS PHASED SYSTEM TO IMPACT THE AREA. GFS AND UKMET HAVE TRENDED TOWARD ECMWF SOLUTION WITH UPPER LOW DEVELOPING OVER DESERT SW AND A MORE PROGRESSIVE NORTHERN STREAM SHORTWAVE TO PASS NORTH OF CWA THU AND THU NIGHT. FOLLOWED BLEND OF GFS AND ECMWF WITH INVERTED SURFACE TROUGH/COLD FRONT PASSING THROUGH ON THU...WHICH DEVELOPS INTO LOW OVER LOWER MID THU NIGHT... THROWING OUT THE NOW OUTLIER NAM DEPICTION OF A MORE PROGRESSIVE SURFACE LOW MOVING ACROSS MN AND WI ON THU. DEVELOPING LOW LEVEL WAA SWRLY FLOW WED NIGHT AND CLOUD COVER WILL PREVENT MUCH OF A TEMPERATURE FALL COMPARED TO PREVIOUS NIGHTS WITH LOWS IN UPPER TEENS TO LOWER 20S. ISENTROPIC SURFACES SHOW SATURATION AND LIGHT SNOW DEVELOPING MAINLY NORTH OF CWA LATE WED NIGHT...BUT THREW IN LOW CHANCE POPS IN FAR NORTH TO ACCOUNT FOR SOME UNCERTAINTY IN THERMAL FIELDS THAT FAR OUT. BEST CHANCES FOR SNOW WILL BE THU INTO THU NIGHT WITH PASSAGE OF MID LEVEL QG FORCING AND SURFACE COLD FRONT. RAISED POPS TO LIKELY ACROSS NORTHERN CWA FOR THU AFTERNOON...THEN HAVE CHANCE POPS OVER ENTIRE AREA THU EVENING WITH BULK OF MEASURABLE SNOW ENDING BY MIDNIGHT. HIGH PRESSURE AND FRESH ARCTIC AIRMASS SLIDES OVER AREA FRI. MOISTURE AND QPF FIELDS SUGGEST SNOWFALL AMOUNTS IN 1 TO 3 INCH RANGE AT BEST. NEW MODEL RUNS CONTINUE TO LOWER H8 TEMPERATURES AND HAVE CONTINUED TO TREND TEMPERATURES DOWNWARD...WITH FRI AM LOWS NOW IN SINGLE DIGITS AND HIGHS LIMITED RANGE OF ABOUT 10 NORTH TO 20 FAR SOUTH. KEPT FRI NIGHT LOWS BELOW ZERO NORTH TO SINGLE DIGITS SOUTH. ONLY MINOR CHANGES SAT THROUGH MON...WITH ANOTHER NORTHERN STREAM WAVE TRYING TO MODERATE TEMPERATURES CLOSER TO NORMAL WITH BULK OF PRECIPITATION POTENTIAL KEPT WELL TO NORTH. ..SHEETS.. && .AVIATION... CLOUDY WITH LOW VFR TO MVFR CONDITIONS WITH CIGS 2-5,000` AGL AND VSBYS 2-6 MILES IN INTERMITTENT SNOW. CONDITIONS TO GRADUALLY IMPROVE BY LATE PM INTO OVERNIGHT HOURS TO VFR UNDER CLEAR TO PARTLY CLOUDY SKIES WITH VSBYS P6SM. SOME RISK AFTER 06Z OF PATCHY FOG DEVELOPMENT WITH LOCALIZED VSBYS AOB 1 MILE...ESPECIALLY NEAR DAWN. ..NICHOLS.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ NICHOLS/SHEETS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 216 AM MST TUE FEB 12 2008 .DISCUSSION...A SECONDARY SURGE OF COLD AIR WILL GLANCE THE FAR NORTHEAST PORTION OF THE FORECAST AREA EARLY IN THE FIRST PERIOD WITH SUBTLE H85 CAA EXPECTED TODAY ACROSS THE ENTIRE FORECAST AREA BEHIND DEPARTING TROUGH. THIS WILL LEAD TO COOLER TEMPERATURES WHEN COMPARED TO PREVIOUS FORECAST HIGHS WITH READINGS ONLY CLIMBING INTO THE LOW-MID 40S IN MOST LOCATIONS. SATELLITE/SFC OBSERVATIONS INDICATE WIDESPREAD MID/HIGH CLOUDS UPSTREAM IN NORTH/NORTHWEST MID/UPPER FLOW SUPPORTING ONLY PARTIAL INSOLATION ADDING SUPPORT FOR COOLER TEMPERATURES. HEIGHTS/THICKNESS WILL RAPIDLY INCREASE ACROSS MUCH OF THE CENTRAL AND SOUTHERN PLAINS STATES ON WEDNESDAY AS MID/UPPER RIDGE TRANSLATES RAPIDLY EAST INTO THE MISSISSIPPI VALLEY LATE IN THE PERIOD. FALLING HEIGHTS ARE EXPECTED ACROSS THE GREAT BASIN AREA AS THE NEXT TROUGH APPROACHES THE CENTRAL ROCKIES LATE IN THE PERIOD. THE WARMEST READINGS OF THE WEEK ARE STILL ON TAP ACROSS THE CENTRAL HIGH PLAINS WITH LOW LEVEL SOUTHWEST WINDS HELPING TO BOOST TEMPERATURES INTO THE MID/UPPER 50S ACROSS THE SOUTHWEST ZONES. ANOTHER COLD FRONT WILL ARRIVE WED NIGHT/EARLY THURSDAY AS H5 TROUGH MOVES INTO THE CENTRAL GREAT BASIN AND APPROACHES THE SOUTHWEST. EXPECT A PERIOD OF POST-FRONTAL SNOW ACROSS THE CENTRAL HIGH PLAINS AS LARGE SCALE FORCING FOR ASCENT INCREASES. ENOUGH RUN-TO-RUN CONSISTENCY FROM THE GFS TO BUMP POPS UP AS CONFIDENCE BEGINS TO INCREASE. RELUCTANT TO MAKE BIG CHANGES ON THURSDAY WITH UNCERTAINTY IN AMOUNT OF MODIFICATION ARCTIC AIR WILL HAVE ON THE SOUTHWEST PERIPHERY OF THERMAL TROUGH...SO FOLLOWED THE GENERAL THEME OF PREVIOUS FORECAST WITH HIGHS IN THE 20S WHILE KEEPING POPS IN THE MID RANGE. TRENDED LOWS DOWN THURSDAY NIGHT AS SFC RIDGE BUILDS SOUTH PROVIDING LIGHT WINDS/CLEARING SKIES AND AN OPPORTUNITY FOR RAPID COOLING WITH FRESH SNOW. DAYS 4 THROUGH 7...NO CHANGES. && .AVIATION...FOR THE 06Z TAF...EXPECT MID LEVEL CLOUD DECK TO HANG AROUND THROUGH MUCH OF THE TAF PERIOD AT BOTH KGLD AND KMCK. WITH WEAK SUBSIDENCE ALOFT AND DRY LAYER AT THE SURFACE...NOT EXPECTING ANY PRECIP THROUGH THE NEXT 24 HOURS. WINDS WILL PICK UP DURING THE DAY ON TUESDAY WITH RUC...GFS...AND NAM SHOWING H85 WINDS IN EXCESS OF 30KTS. AS A RESULT...INSERTED GUSTS FROM AROUND 18Z TUESDAY THROUGH 02Z WEDNESDAY. PRESSURE GRADIENT BEGINS TO RELAX AFTER 02Z ALLOWING WINDS TO SUBSIDE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ MCGUIRE/FOLTZ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1048 PM MST MON FEB 11 2008 .AVIATION...FOR THE 06Z TAF...EXPECT MID LEVEL CLOUD DECK TO HANG AROUND THROUGH MUCH OF THE TAF PERIOD AT BOTH KGLD AND KMCK. WITH WEAK SUBSIDENCE ALOFT AND DRY LAYER AT THE SURFACE...NOT EXPECTING ANY PRECIP THROUGH THE NEXT 24 HOURS. WINDS WILL PICK UP DURING THE DAY ON TUESDAY WITH RUC...GFS...AND NAM SHOWING H85 WINDS IN EXCESS OF 30KTS. AS A RESULT...INSERTED GUSTS FROM AROUND 18Z TUESDAY THROUGH 02Z WEDNESDAY. PRESSURE GRADIENT BEGINS TO RELAX AFTER 02Z ALLOWING WINDS TO SUBSIDE. && .PREV DISCUSSION... /ISSUED 220 PM MST MON FEB 11 2008/ .DISCUSSION...A WARM FRONT OVER WESTERN KANSAS WILL CONTINUE TO PUSH THE COLD AIR OUT OF THE REGION THIS AFTERNOON. TEMPERATURES VARIED WIDELY EARLIER THIS AFTERNOON WHERE KGLD AND KITR HAD WARMED INTO THE LOWER 50S AND FURTHER EAST KHLC AND KMCK WERE STRUGGLING OUT OF THE THIRTIES. WILL SEE THE COLD AIR CONTINUE TO ERODE OUT OF WESTERN KANSAS. VISIBLE SATELLITE IMAGERY SHOWS SOME WEAK CONVECTION EAST OF THE FRONT RANGE IN COLORADO WHERE SOME COOLER AIR HAS BEGUN TO POOLS EAST MAY SEE SOME VIRGA AND SPRINKLES OVER EASTERN COLORADO OTHERWISE THE FA WILL REMAIN DRY. TEMPERATURE-WISE...TUESDAY LOOKS SIMILAR TO TODAY AS NORTHWEST FLOW RESUMES. WEDNESDAY CONTINUES TO BE THE WARMEST DAY OF THE WEEK AS THE FA EXPERIENCES AMPLE WAA. H85 TEMPERATURES WARM NEAR 14C ACROSS THE SOUTHERN PORTIONS OF THE CWA. BY WEDNESDAY NIGHT A SHORTWAVE TROUGH STRENGTHENS AS IT SLIDES ACROSS THE FORECAST AREA. ANOTHER COLD FRONT MAKES ITS WAY INTO THE TRI-STATE AREA LATE WEDNESDAY NIGHT WHICH WILL KEEP MAX TEMPERATURES THURSDAY SOME 30 DEGREES COLDER THAN WEDNESDAY. FCAST MODELS HAVE BEEN FAIRLY CONSISTENT WITH TIMING AND PRECIPITATION AMOUNTS THURSDAY MORNING THROUGH FRIDAY MORNING. SNOWFALL WILL BEGIN FROM THE NORTHWEST AND FILL IN TO THE SOUTHEAST AS THE DAY PROGRESSES. AM STILL NOT LOOKING FOR MUCH IN THE WAY OF ACCUMULATION...FOR NOW AM THINKING LESS THAN AN INCH IN MOST PLACES. HOWEVER...IF THIS SYSTEM SLOWS DOWN FROM WHAT IS CURRENTLY FORECASTED...COULD SEE MORE ACCUMULATION. WILL CONTINUE TO MONITOR THIS SYSTEM AS THE WEEK PROGRESSES. WEST/NORTHWESTERLY FLOW PICKS UP FRIDAY MORNING AND AFTERNOON THUS PUSHING THE COLD AIR OUT OF THE REGION. SHOULD SEE HIGH TEMPS FRIDAY INTO THE MID/UPPER 30S AND SATURDAY MID/UPPER 40S SATURDAY AHEAD OF YET ANOTHER SHOT OF COLD AIR TO REACH THE FORECAST AREA. SUNDAY AND MONDAY...CONSIDERABLE DISAGREEMENT AMONG SOLUTIONS OF THE SATURDAY NIGHT TROUGH AS EXPECTED WITH A SPLIT FLOW PATTERN. GFS SHOWS MAIN TROUGH DIGGING AND EVENTUALLY JOINING WITH THE SOUTHERLY LOW ALONG THE EAST COAST...WHILE THE ECMWF SHOWS THE LOW AND TROUGH INTERACTING CLOSER TO THE MIDWEST. MOST CANADIAN AND NCEP ENSEMBLE MEMBERS SEAM TO AGREE MORE WITH THE GFS SOLUTION. SLIGHT CHANCE POPS WERE ADDED TO THE 00Z - 12Z SUNDAY PERIOD...IF THE GFS SOLUTION IS CORRECT...THERE IS LIMITED MOISTURE FOR SOME LIGHT SNOW. DISAGREEMENT AMONG SOLUTIONS CARRIES OVER TO TEMPERATURES WITH THE ECMWF ABOUT 5 TO 10 DEGREES LOWER AT 850MB COMPARED TO GFS. FOR NOW FORECAST FAVORS THE GFS...BUT WOULD NOT BE SURPRISED IF THERE ARE CONSIDERABLE CHANGES IN SUBSEQUENT MODEL RUNS. && && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ FOLTZ/BURTIS ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1154 AM MST MON FEB 11 2008 .DISCUSSION...INCREASED TEMPERATURES A FEW DEGREES IN WESTERN AREAS WHERE TEMPS HAVE ALREADY REACHED 51 DEGREES. ALSO BUMPED WINDS UP WITH GUSTS TO 35 MPH IN THE WEST. LOOKS LIKE A FEW HOURS OF GOOD MIXING AHEAD WITH UPSTREAM GUSTS TO 38 MPH NOTED AT AKO. NOTICED THAT YUMA TEMPERATURE DROPPED 2 DEGREES LAST HOUR WHICH MAY BE A REFLECTION OF THE MINOR 850 COOLING INDICATED ON NAM GUIDANCE COMING IN FROM THE NORTHWEST DURING THE AFTERNOON HOURS. && .PREVIOUS DISCUSSION... /1004 AM MST MON FEB 11 2008/ .DISCUSSION...THE WESTERN EDGE OF THE ARCTIC AIR CONTINUES TO SLOWLY ERODE EASTWARD THIS MORNING. AT 15Z THE WESTERN EDGE LIES ABOUT ON A TRENTON NEBRASKA TO OAKLEY TO SCOTT CITY LINE. WEST OF THIS LINE SURFACE WINDS ARE WESTERLY AND TEMPERATURES HAVE CLIMBED INTO THE LOWER 40S WHILE FURTHER EAST WINDS ARE SOUTHERLY WITH TEMPERATURES HOLDING IN THE LOWER 20S. LATEST GUIDANCE INDICATES THE ARCTIC BOUNDARY WILL SLIP EASTWARD TO THE HILL CITY AREA BY LATE AFTERNOON. IN LIGHT OF CURRENT SURFACE DATA AND TRENDS HAVE INCREASED MAX TEMPERATURES OVER COLORADO AND WESTERN TIER OF KANSAS COUNTIES TO 50 DEGREES WHILE MAINTAINING PREVIOUS FORECAST HIGH IN THE UPPER 30S IN THE EAST. CURRENT TEMPERATURE AT GLD IS 44 DEGREES BUT NAM GUIDANCE SHOWS COOLING AT 850 MB DURING THE AFTERNOON WHICH SHOULD KEEP TEMPERATURES IN CHECK. ONE CONCERN FOR THIS AFTERNOON IS THE AMOUNT OF WIND TO IMPACT THE COLORADO AND EXTREME WESTERN KANSAS COUNTIES. LATEST RUC AND NAM SHOW ABOUT A 4 HOUR PERIOD WHERE 850 MB WINDS INCREASE TO 40-45 KTS. MAIN QUESTION IS WHETHER OR NOT WE WILL MIX THAT LAYER TO THE SURFACE. BUFKIT SHOWS STRONG LOW LEVEL WINDS BUT LITTLE MIXING INTO THAT LAYER. FOR NOW HAVE DECIDED TO STICK WITH CURRENT GRIDS WHICH HAVE 15-25 MPH NW WINDS FOR THIS AFTERNOON AND WILL MONITOR SITUATION. && .AVIATION...FOR 18Z TAFS...LOW STRATUS CONTINUES TO ERODE QUICKLY WITH WESTERLY AND SOUTHWESTERLY WINDS...AND SHOULD BE OUT OF THE REGION SHORTLY. FOR THE REST OF THE TAF PERIOD EXPECT VFR CONDITIONS AT BOTH KGLD AND KMCK WITH ONLY HIGH CIRRUS CLOUDS. LOOKING AT PROFILER DATA AND UPSTREAM OBS...WINDS JUST OFF THE SURFACE AT 850 AND 700MB ARE AS HIGH AS 50KTS. EXPECTATION IS THAT AT LEAST A FRACTION OF THOSE WINDS WILL MIX DOWN...AND BELIEVE THAT MODEL WINDS ARE UNDERDONE THROUGH THE DAY. EXPECT WINDS TO DIMINISH AFTER 00Z WITH THE LOSS OF DIURNAL MIXING AND A DECREASE IN THE PRESSURE GRADIENT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DLF/JOHNSON ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1144 AM CST MON FEB 11 2008 .AVIATION... FOR 18Z TAFS...MAIN AVIATION CONCERN FOR THE NEXT 24 HOURS WILL BE LOW CLOUDS. CONFIDENCE IS HIGH THAT IFR CIGS WILL CONTINUE TO IMPACT KCNU THROUGH AT LEAST 00Z IF NOT LONGER. OVER THE LAST FEW HOURS CIGS HAVE EVEN DROPPED TO BELOW LIFR. WENT AHEAD AND PUT A TEMPO IN AT KICT FOR IFR CIGS AS A SMALL BAND OF LOWER CLOUDS HAS BEEN LINGERING OVER NORTHERN SG COUNTY FOR THE LAST FEW HOURS AND IS ATTEMPTING TO PUSH SLOWLY SOUTH. FURTHER NORTH CONFIDENCE IS HIGH THAT VFR CONDITIONS WILL PREVAIL AT KRSL AND KSLN THROUGH 00Z. A FAST MOVING UPPER WAVE IS EXPECTED TO SLIDE SOUTH ACROSS NEBRASKA LATE THIS AFTERNOON THROUGH THE OVERNIGHT HOURS. THIS WILL RESULT IN SURFACE WINDS FLIPPING AROUND TO THE NORTH AFTER DARK OVER CENTRAL KS BRINGING ANOTHER SHOT OF COOLER AIR AND LOWER CIGS. AT THIS POINT AM GOING WITH THE THINKING THAT CIGS WILL GENERALLY BE ABOVE IFR AS THE COOLER AIR MOVES IN OVERNIGHT AREAWIDE. && .PREV DISCUSSION... /ISSUED 1033 AM CST MON FEB 11 2008/ UPDATE... WILL FIRE OUT INITIAL UPDATE TO CANCEL PORTIONS OF HEADLINES AND TO TWEAK PRECIP CHANCES. PRECIP COVERAGE OVER THE LAST COUPLE OF HOURS HAS PUSHED SLOWLY SOUTHEAST INTO EXTREME SE KS. RUC ANALYSIS IS INDICATING THE BEST LOW LEVEL MOISTURE TRANSPORT HAS NOW FOCUSED OVER SOUTH CENTRAL MO WHERE PRECIP IS MORE WIDESPREAD. RUC AND NAM BOTH AGREE ON KEEPING THE BEST PRECIP CHANCES OVER EXTREME SE KS FOR THE NEXT FEW HOURS. THEREFORE WILL TRIM BACK PRECIP CHANCES FURTHER WEST AND CANCEL A FEW COUNTIES FROM HEADLINES. AT THIS TIME AM MOST CONCERNED WITH LABETTE AND MONTGOMERY COUNTIES PICKING UP ADDITION ICE ACCUMULATION. LAWSON PREV DISCUSSION... /ISSUED 638 AM CST MON FEB 11 2008/ UPDATE... THOUGH PRECIP ABOUT DONE IN THE WICHITA AREA...WILL CONTINUE THE ADVISORY THROUGH THE MORNING RUSH TO SCHOOL/WORK DUE TO SLICK CONDITIONS FROM EARLIER SLEET/HAIL AND FREEZING RAIN. THE MORE SIGNIFICANT ICE WILL CONTINUE FOR MUCH OF SOUTHEAST KANSAS INTO MIDDAY...WHERE ACCUMS ALREADY TO ONE-HALF INCH IN SOME AREAS. KED AVIATION... FOR THE 12Z TAF SUITE...AREAS OF FREEZING RAIN/SLEET AND THUNDER WILL CONTINUE FOR SOUTHEAST KANSAS INTO MIDDAY. MVFR CONDITIONS EXPECTED WITH THE WINTRY PRECIP...WITH MAINLY VFR STRATOCU CIGS FURTHER WEST ACROSS PARTS OF CENTRAL KANSAS. THE MIXED PRECIP IS EXPECTED TO DIMINISH LATER THIS AFTERNOON WITH GENERALLY VFR CIGS FOR LATTER PORTION OF THE FORECAST VALID PERIOD. KED PREV DISCUSSION... /ISSUED 319 AM CST MON FEB 11 2008/ DISCUSSION... MAIN FORECAST CONCERN IS HOW MUCH ICE ACCUMULATION THE SOUTHEAST HALF OF THE AREA WILL SEE TODAY AND WHEN IT WILL END. TODAY-TONIGHT: LOW LEVELS ARE MOISTENING UP ACROSS NORTHEAST OKLAHOMA AND SOUTHERN KANSAS THIS MORNING...AND PRECIPITATION IS ONGOING EARLY THIS MORNING. AT THIS POINT PRECIPITATION TYPE HAS BEEN MAINLY SLEET...WHICH AGREES WITH WHAT THE FORECAST SOUNDINGS ARE SHOWING FOR 06Z TO 12Z. AFTER 12Z...THE LOWER LEVELS WARM UP AND FREEZING RAIN IS MOST LIKELY. MOISTURE TRANSPORT KEEPS BEST CHANCES FOR PRECIPITATION TOWARD SOUTHEAST KANSAS...AND THAT IS WHERE THE BETTER INSTABILITY IS AS WELL. WOULD EXPECT TO SEE SCATTERED THUNDER ESPECIALLY IN FAR SOUTHEAST KANSAS BETWEEN 10Z AND 14Z. BEST 3-6KM SHEAR (50 TO 60 KNOTS) IS SOUTHEAST OF A LINE FROM ABOUT WELLINGTON TO YATES CENTER BETWEEN 09Z AND 12Z. HIGHEST QPF WILL BE WHERE THERE ARE THUNDERSTORMS...AND SOME OF THE STRONGER STORMS COULD HAVE SOME SMALL HAIL AS WELL. A COUPLE CHANGES TO HEADLINES TODAY. PER RADAR TRENDS THIS MORNING...WILL ISSUE WINTER WEATHER ADVISORY FOR RENO...KINGMAN...HARPER AND HARVEY COUNTIES UNTIL 15Z. ALSO...GIVEN HOW MUCH PRECIPITATION COWLEY COUNTY HAS ALREADY RECEIVED...WILL UPGRADE THEM TO A WARNING. OTHERWISE...BETWEEN THE THUNDERSTORM POTENTIAL AND THE LONGER DURATION OF PRECIPITATION IN SOUTHEAST KANSAS...WE WILL CONTINUE THE WINTER STORM WARNING AS IS. THE NORTHERN PORTION OF THE WARNING MAY NEED TO BE DOWNGRADED LATER THIS MORNING IF IT LOOKS LIKE THOSE COUNTIES (MAINLY WOODSON...ALLEN AND CHASE) WILL NOT RECEIVE AS MUCH QPF AS IS THEIR POTENTIAL. AS FOR THE ADVISORY...NO OTHER CHANGES WILL BE MADE TO THAT EITHER. WESTERN FRINGE OF COUNTIES MIGHT NOT SEE MUCH ICE...BUT IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS ON ROADWAYS. THIS IS ESPECIALLY TRUE DURING THE MORNING COMMUTE. BOTH NAM AND GFS SHOW STRONG SUBSIDENCE AND DRYING BELOW 800MB BY 00Z FOR MOST IF NOT ALL OF THE FORECAST AREA. ONLY EXCEPTION IS VERY FAR SOUTHEAST KANSAS. THEREFORE HAVE MADE THE NECESSARY CHANGES FOR TONIGHT. TUESDAY-WEDNESDAY: SOUNDINGS DRY OUT AND SKIES SHOULD BE MOSTLY SUNNY THROUGH THIS PART OF THE FORECAST WITH SURFACE HIGH PRESSURE IN PLACE. NEXT LOW BEGINS TO DEEPEN IN THE ROCKIES...WHICH WILL AFFECT THE FORECAST AREA ON THURSDAY INTO FRIDAY. SEASONABLE TEMPERATURES LOOK REASONABLE ON TUESDAY...AND GUSTY SOUTHERLY WINDS ON WEDNESDAY WILL BRING TEMPERATURES IN THE 50S BEFORE THE NEXT COOL DOWN. THURSDAY-SUNDAY: THE NEXT LOW FOR THURSDAY INTO FRIDAY WILL HAVE MORE MOISTURE THAN THE SYSTEM THIS MORNING...AND TEMPERATURE PROFILES WOULD INDICATE SNOW AS THE PRECIPITATION TYPE. SURFACE HIGH PRESSURE BUILDS IN AGAIN ON FRIDAY AND REMAINS THROUGH THE WEEKEND...KEEPING THE FORECAST AREA DRY DURING THAT TIME. FORECAST FOR THIS TIME FRAME LOOKS TO BE ON TRACK...SO NO CHANGES MADE. SCHRECK AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...LOW-MID LEVEL MOISTURE IS ON THE INCREASE ACROSS THE SOUTHERN/CENTRAL PLAINS...AND IS EVIDENT IN FREEZING RAIN SHOWERS DEVELOPING ACROSS NORTHERN OKLAHOMA OVER THE PAST FEW HOURS. WOULD EXPECT THIS ACTIVITY TO CONTINUE SPREADING/DEVELOPING NORTH/NORTHEASTWARD AS THE OVERNIGHT PROGRESSES AS LOW-LEVEL WARM ADVECTION/MOISTURE TRANSPORT CONTINUES TO SPREAD NORTHEAST...AND EVENTUALLY GET INTO PORTIONS OF SOUTH-CENTRAL AND SOUTHEAST KANSAS BY 10Z (4AM) OR SO. CNU HAS THE BEST CHANCE OF BEING AFFECTED...WITH ICT PROBABLY BEING AFFECTED BRIEFLY LATE TONIGHT THROUGH EARLY MONDAY MORNING. ALSO INSERTED VCTS WORDING IN THE CNU TAF...DUE TO SOME ELEVATED INSTABILITY. KLEINSASSER && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 38 22 41 25 / 10 10 10 0 HUTCHINSON 39 18 43 24 / 10 10 10 0 NEWTON 37 21 39 25 / 10 10 10 0 ELDORADO 36 21 38 23 / 10 10 10 0 WINFIELD-KWLD 38 24 42 27 / 20 10 10 0 RUSSELL 39 20 42 25 / 10 10 0 0 GREAT BEND 41 20 44 25 / 10 10 0 0 SALINA 36 18 37 25 / 10 10 0 0 MCPHERSON 38 19 40 24 / 10 10 10 0 COFFEYVILLE 34 27 38 23 / 70 40 10 0 CHANUTE 33 23 37 22 / 20 10 10 0 IOLA 33 21 36 22 / 10 10 10 0 PARSONS-KPPF 34 24 38 21 / 50 20 10 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 3 PM CST THIS AFTERNOON FOR KSZ094>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1004 AM MST MON FEB 11 2008 .DISCUSSION...THE WESTERN EDGE OF THE ARCTIC AIR CONTINUES TO SLOWLY ERODE EASTWARD THIS MORNING. AT 15Z THE WESTERN EDGE LIES ABOUT ON A TRENTON NEBRASKA TO OAKLEY TO SCOTT CITY LINE. WEST OF THIS LINE SURFACE WINDS ARE WESTERLY AND TEMPERATURES HAVE CLIMBED INTO THE LOWER 40S WHILE FURTHER EAST WINDS ARE SOUTHERLY WITH TEMPERATURES HOLDING IN THE LOWER 20S. LATEST GUIDANCE INDICATES THE ARCTIC BOUNDARY WILL SLIP EASTWARD TO THE HILL CITY AREA BY LATE AFTERNOON. IN LIGHT OF CURRENT SURFACE DATA AND TRENDS HAVE INCREASED MAX TEMPERATURES OVER COLORADO AND WESTERN TIER OF KANSAS COUNTIES TO 50 DEGREES WHILE MAINTAINING PREVIOUS FORECAST HIGH IN THE UPPER 30S IN THE EAST. CURRENT TEMPERATURE AT GLD IS 44 DEGREES BUT NAM GUIDANCE SHOWS COOLING AT 850 MB DURING THE AFTERNOON WHICH SHOULD KEEP TEMPERATURES IN CHECK. ONE CONCERN FOR THIS AFTERNOON IS THE AMOUNT OF WIND TO IMPACT THE COLORADO AND EXTREME WESTERN KANSAS COUNTIES. LATEST RUC AND NAM SHOW ABOUT A 4 HOUR PERIOD WHERE 850 MB WINDS INCREASE TO 40-45 KTS. MAIN QUESTION IS WHETHER OR NOT WE WILL MIX THAT LAYER TO THE SURFACE. BUFKIT SHOWS STRONG LOW LEVEL WINDS BUT LITTLE MIXING INTO THAT LAYER. FOR NOW HAVE DECIDED TO STICK WITH CURRENT GRIDS WHICH HAVE 15-25 MPH NW WINDS FOR THIS AFTERNOON AND WILL MONITOR SITUATION. && .AVIATION...FOR 18Z TAFS...LOW STRATUS CONTINUES TO ERODE QUICKLY WITH WESTERLY AND SOUTHWESTERLY WINDS...AND SHOULD BE OUT OF THE REGION SHORTLY. FOR THE REST OF THE TAF PERIOD EXPECT VFR CONDITIONS AT BOTH KGLD AND KMCK WITH ONLY HIGH CIRRUS CLOUDS. LOOKING AT PROFILER DATA AND UPSTREAM OBS...WINDS JUST OFF THE SURFACE AT 850 AND 700MB ARE AS HIGH AS 50KTS. EXPECTATION IS THAT AT LEAST A FRACTION OF THOSE WINDS WILL MIX DOWN...AND BELIEVE THAT MODEL WINDS ARE UNDERDONE THROUGH THE DAY. EXPECT WINDS TO DIMINISH AFTER 00Z WITH THE LOSS OF DIURNAL MIXING AND A DECREASE IN THE PRESSURE GRADIENT. && .PREVIOUS DISCUSSION... /ISSUED 1235 AM MST MON FEB 11 2008/ .DISCUSSION...A SHORTWAVE TROUGH MOVING OVER THE NORTHERN ROCKIES EARLY THIS MORNING WILL CONTINUE SOUTHEAST IMPACTING THE CENTRAL HIGH PLAINS LATE THIS AFTERNOON AND POSSIBLY INTO THE EARLY EVENING HOURS. ONLY A MINOR IMPACT IS EXPECTED WITH LATE AFTERNOON VIRGA/PERHAPS A SPRINKLE OR FLURRY WEIGHTED ACROSS THE WESTERN ZONES. A SECONDARY CONCERN WILL BE INCREASING NORTHWEST WINDS AND WILL TREND SPEEDS UP SLIGHTLY AS CROSS-SECTIONS OF WIND/MIXING LAYER HEIGHT SUGGEST 25-30 KNOTS POSSIBLE...HOWEVER WITH INCREASING CLOUDS/COLD GROUND TEMPERATURES THE DEPTH OF MIXING REMAINS UNCERTAIN. 07Z SFC ANALYSIS INDICATES THE ARCTIC COLD FRONT HAS RETREATED EAST WITH TEMPERATURES STEADY/SLOWLY RISING ACROSS MUCH OF THE WESTERN ZONES. HOW FAR EAST THE BOUNDARY MIXES REMAINS UNCERTAIN AND WILL LEAN COOLER ACROSS THE FAR EASTERN ZONES TO ACCOUNT FOR UNCERTAINTY WHILE BOOSTING HIGHS IN TO THE MID 40S ACROSS MUCH OF THE WEST. HIGH TEMPERATURES NEAR NORMAL ARE EXPECTED AGAIN ON TUESDAY WITH MID 40S EXPECTED ACROSS THE FORECAST AREA. THE PREVIOUS FORECAST CAPTURED THIS WELL WITH LITTLE CHANGES PLANNED AT THIS TIME. THE WARMEST DAY OF THE WEEK IS EXPECTED ON WEDNESDAY WITH PRE-FRONTAL TROUGH/SOUTHWEST DOWNSLOPE HELPING TO BOOST TEMPERATURES INTO THE MID/UPPER 50S. A SHORTWAVE TROUGH WILL DIG INTO THE NORTHERN PLAINS/CENTRAL ROCKIES WEDNESDAY NIGHT WHILE A COLD FRONT MOVES OVER THE CENTRAL HIGH PLAINS. LARGE SCALE FORCING FOR ASCENT WILL INCREASE WEDNESDAY NIGHT WITH APPROACHING TROUGH. THE PREVIOUS FORECAST CAPTURED THE ANTICIPATED SCENARIO WELL WITH MID POPS AND SEE LITTLE REASON TO DEVIATE AT THIS TIME. DAYS 4 THROUGH 7...NO CHANGES. && .AVIATION...STRATUS REMAINS THE FORECAST CHALLENGE THROUGH 12Z AT KGLD/KMCK. LOW CLOUDS DEVELOPED AS EXPECTED AROUND SUNSET...BUT SOUTHWEST DOWNSLOPE WINDS ARE SLOWLY DRYING THE AIR MASS WEST OF KGLD. CEILINGS ROSE RAPIDLY AT KITR WHEN DOWNSLOPE WINDS DEVELOPED THERE. LATEST SATELLITE IMAGERY SHOWS CLOUDS MOVING EAST OF KGLD. WILL KEEP IFR CEILINGS THERE FOR A FEW HOURS...BUT WILL RAISE THEM TO VFR CONDITIONS AFTER 10Z. KMCK IS ON THE WESTERN EDGE OF LOW CLOUDS...BUT SOME SECONDARY DEVELOPMENT IS TAKING PLACE BETWEEN KLBF AND KIML. WILL MENTION SCATTERED CLOUDS AROUND 2000 FEET WITH A TEMPO MVFR GROUP THROUGH 10Z...THEN GRADUALLY RAISE CEILINGS TO VFR. SHOULD HAVE ABUNDANT MID LEVEL CLOUDS THE REST OF THE DAY AT BOTH SITES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ MCGUIRE/MENTZER/DLF/JOHNSON ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1033 AM CST MON FEB 11 2008 .UPDATE... WILL FIRE OUT INITIAL UPDATE TO CANCEL PORTIONS OF HEADLINES AND TO TWEAK PRECIP CHANCES. PRECIP COVERAGE OVER THE LAST COUPLE OF HOURS HAS PUSHED SLOWLY SOUTHEAST INTO EXTREME SE KS. RUC ANALYSIS IS INDICATING THE BEST LOW LEVEL MOISTURE TRANSPORT HAS NOW FOCUSED OVER SOUTH CENTRAL MO WHERE PRECIP IS MORE WIDESPREAD. RUC AND NAM BOTH AGREE ON KEEPING THE BEST PRECIP CHANCES OVER EXTREME SE KS FOR THE NEXT FEW HOURS. THEREFORE WILL TRIM BACK PRECIP CHANCES FURTHER WEST AND CANCEL A FEW COUNTIES FROM HEADLINES. AT THIS TIME AM MOST CONCERNED WITH LABETTE AND MONTGOMERY COUNTIES PICKING UP ADDITION ICE ACCUMULATION. LAWSON && .PREV DISCUSSION... /ISSUED 638 AM CST MON FEB 11 2008/ UPDATE... THOUGH PRECIP ABOUT DONE IN THE WICHITA AREA...WILL CONTINUE THE ADVISORY THROUGH THE MORNING RUSH TO SCHOOL/WORK DUE TO SLICK CONDITIONS FROM EARLIER SLEET/HAIL AND FREEZING RAIN. THE MORE SIGNIFICANT ICE WILL CONTINUE FOR MUCH OF SOUTHEAST KANSAS INTO MIDDAY...WHERE ACCUMS ALREADY TO ONE-HALF INCH IN SOME AREAS. KED AVIATION... FOR THE 12Z TAF SUITE...AREAS OF FREEZING RAIN/SLEET AND THUNDER WILL CONTINUE FOR SOUTHEAST KANSAS INTO MIDDAY. MVFR CONDITIONS EXPECTED WITH THE WINTRY PRECIP...WITH MAINLY VFR STRATOCU CIGS FURTHER WEST ACROSS PARTS OF CENTRAL KANSAS. THE MIXED PRECIP IS EXPECTED TO DIMINISH LATER THIS AFTERNOON WITH GENERALLY VFR CIGS FOR LATTER PORTION OF THE FORECAST VALID PERIOD. KED PREV DISCUSSION... /ISSUED 319 AM CST MON FEB 11 2008/ DISCUSSION... MAIN FORECAST CONCERN IS HOW MUCH ICE ACCUMULATION THE SOUTHEAST HALF OF THE AREA WILL SEE TODAY AND WHEN IT WILL END. TODAY-TONIGHT: LOW LEVELS ARE MOISTENING UP ACROSS NORTHEAST OKLAHOMA AND SOUTHERN KANSAS THIS MORNING...AND PRECIPITATION IS ONGOING EARLY THIS MORNING. AT THIS POINT PRECIPITATION TYPE HAS BEEN MAINLY SLEET...WHICH AGREES WITH WHAT THE FORECAST SOUNDINGS ARE SHOWING FOR 06Z TO 12Z. AFTER 12Z...THE LOWER LEVELS WARM UP AND FREEZING RAIN IS MOST LIKELY. MOISTURE TRANSPORT KEEPS BEST CHANCES FOR PRECIPITATION TOWARD SOUTHEAST KANSAS...AND THAT IS WHERE THE BETTER INSTABILITY IS AS WELL. WOULD EXPECT TO SEE SCATTERED THUNDER ESPECIALLY IN FAR SOUTHEAST KANSAS BETWEEN 10Z AND 14Z. BEST 3-6KM SHEAR (50 TO 60 KNOTS) IS SOUTHEAST OF A LINE FROM ABOUT WELLINGTON TO YATES CENTER BETWEEN 09Z AND 12Z. HIGHEST QPF WILL BE WHERE THERE ARE THUNDERSTORMS...AND SOME OF THE STRONGER STORMS COULD HAVE SOME SMALL HAIL AS WELL. A COUPLE CHANGES TO HEADLINES TODAY. PER RADAR TRENDS THIS MORNING...WILL ISSUE WINTER WEATHER ADVISORY FOR RENO...KINGMAN...HARPER AND HARVEY COUNTIES UNTIL 15Z. ALSO...GIVEN HOW MUCH PRECIPITATION COWLEY COUNTY HAS ALREADY RECEIVED...WILL UPGRADE THEM TO A WARNING. OTHERWISE...BETWEEN THE THUNDERSTORM POTENTIAL AND THE LONGER DURATION OF PRECIPITATION IN SOUTHEAST KANSAS...WE WILL CONTINUE THE WINTER STORM WARNING AS IS. THE NORTHERN PORTION OF THE WARNING MAY NEED TO BE DOWNGRADED LATER THIS MORNING IF IT LOOKS LIKE THOSE COUNTIES (MAINLY WOODSON...ALLEN AND CHASE) WILL NOT RECEIVE AS MUCH QPF AS IS THEIR POTENTIAL. AS FOR THE ADVISORY...NO OTHER CHANGES WILL BE MADE TO THAT EITHER. WESTERN FRINGE OF COUNTIES MIGHT NOT SEE MUCH ICE...BUT IT DOES NOT TAKE MUCH TO CAUSE PROBLEMS ON ROADWAYS. THIS IS ESPECIALLY TRUE DURING THE MORNING COMMUTE. BOTH NAM AND GFS SHOW STRONG SUBSIDENCE AND DRYING BELOW 800MB BY 00Z FOR MOST IF NOT ALL OF THE FORECAST AREA. ONLY EXCEPTION IS VERY FAR SOUTHEAST KANSAS. THEREFORE HAVE MADE THE NECESSARY CHANGES FOR TONIGHT. TUESDAY-WEDNESDAY: SOUNDINGS DRY OUT AND SKIES SHOULD BE MOSTLY SUNNY THROUGH THIS PART OF THE FORECAST WITH SURFACE HIGH PRESSURE IN PLACE. NEXT LOW BEGINS TO DEEPEN IN THE ROCKIES...WHICH WILL AFFECT THE FORECAST AREA ON THURSDAY INTO FRIDAY. SEASONABLE TEMPERATURES LOOK REASONABLE ON TUESDAY...AND GUSTY SOUTHERLY WINDS ON WEDNESDAY WILL BRING TEMPERATURES IN THE 50S BEFORE THE NEXT COOL DOWN. THURSDAY-SUNDAY: THE NEXT LOW FOR THURSDAY INTO FRIDAY WILL HAVE MORE MOISTURE THAN THE SYSTEM THIS MORNING...AND TEMPERATURE PROFILES WOULD INDICATE SNOW AS THE PRECIPITATION TYPE. SURFACE HIGH PRESSURE BUILDS IN AGAIN ON FRIDAY AND REMAINS THROUGH THE WEEKEND...KEEPING THE FORECAST AREA DRY DURING THAT TIME. FORECAST FOR THIS TIME FRAME LOOKS TO BE ON TRACK...SO NO CHANGES MADE. SCHRECK AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...LOW-MID LEVEL MOISTURE IS ON THE INCREASE ACROSS THE SOUTHERN/CENTRAL PLAINS...AND IS EVIDENT IN FREEZING RAIN SHOWERS DEVELOPING ACROSS NORTHERN OKLAHOMA OVER THE PAST FEW HOURS. WOULD EXPECT THIS ACTIVITY TO CONTINUE SPREADING/DEVELOPING NORTH/NORTHEASTWARD AS THE OVERNIGHT PROGRESSES AS LOW-LEVEL WARM ADVECTION/MOISTURE TRANSPORT CONTINUES TO SPREAD NORTHEAST...AND EVENTUALLY GET INTO PORTIONS OF SOUTH-CENTRAL AND SOUTHEAST KANSAS BY 10Z (4AM) OR SO. CNU HAS THE BEST CHANCE OF BEING AFFECTED...WITH ICT PROBABLY BEING AFFECTED BRIEFLY LATE TONIGHT THROUGH EARLY MONDAY MORNING. ALSO INSERTED VCTS WORDING IN THE CNU TAF...DUE TO SOME ELEVATED INSTABILITY. KLEINSASSER && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 38 22 41 25 / 10 10 10 0 HUTCHINSON 39 18 43 24 / 10 10 10 0 NEWTON 37 21 39 25 / 10 10 10 0 ELDORADO 36 21 38 23 / 10 10 10 0 WINFIELD-KWLD 38 24 42 27 / 20 10 10 0 RUSSELL 39 20 42 25 / 10 10 0 0 GREAT BEND 41 20 44 25 / 10 10 0 0 SALINA 36 18 37 25 / 10 10 0 0 MCPHERSON 38 19 40 24 / 10 10 10 0 COFFEYVILLE 34 27 38 23 / 70 40 10 0 CHANUTE 33 23 37 22 / 20 10 10 0 IOLA 33 21 36 22 / 10 10 10 0 PARSONS-KPPF 34 24 38 21 / 50 20 10 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 3 PM CST THIS AFTERNOON FOR KSZ094>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WICHITA KS 1142 PM CST SUN FEB 10 2008 .AVIATION... 06Z TAFS...ICT/SLN/HUT/CNU/RSL...LOW-MID LEVEL MOISTURE IS ON THE INCREASE ACROSS THE SOUTHERN/CENTRAL PLAINS...AND IS EVIDENT IN FREEZING RAIN SHOWERS DEVELOPING ACROSS NORTHERN OKLAHOMA OVER THE PAST FEW HOURS. WOULD EXPECT THIS ACTIVITY TO CONTINUE SPREADING/DEVELOPING NORTH/NORTHEASTWARD AS THE OVERNIGHT PROGRESSES AS LOW-LEVEL WARM ADVECTION/MOISTURE TRANSPORT CONTINUES TO SPREAD NORTHEAST...AND EVENTUALLY GET INTO PORTIONS OF SOUTH-CENTRAL AND SOUTHEAST KANSAS BY 10Z (4AM) OR SO. CNU HAS THE BEST CHANCE OF BEING AFFECTED...WITH ICT PROBABLY BEING AFFECTED BRIEFLY LATE TONIGHT THROUGH EARLY MONDAY MORNING. ALSO INSERTED VCTS WORDING IN THE CNU TAF...DUE TO SOME ELEVATED INSTABILITY. KLEINSASSER && .PREV DISCUSSION... /ISSUED 946 PM CST SUN FEB 10 2008/ UPDATE... SENT AN UPDATE TO INCLUDE SEDGWICK AND SUMNER COUNTIES IN A WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH TOMORROW MORNING. 00Z NAM AND RUC 925-850MB MOISTURE FIELDS INITIALIZED WELL WITH 00Z RAOBS. LATEST DATA CONTINUES TO SUGGEST GREATEST POTENTIAL FOR ICE ACCUMULATIONS OVER SOUTHEAST KANSAS...WHERE LOW-LEVEL WARM ADVECTION...MOISTURE TRANSPORT AND INSTABILITY WILL BE MAXIMIZED. WILL CONTINUE WINTER STORM WARNING THERE...WHERE DEEP MOIST ELEVATED CONVECTION COULD RESULT IN RAPID ICE ACCUMULATIONS OF GREATER THAN ONE-QUARTER INCH. THINKING WICHITA WILL BE ON THE WEST/NORTHWEST FRINGES OF THE FREEZING PRECIPITATION. HOWEVER...GIVEN THAT THE POTENTIAL WILL OCCUR DURING THE MORNING COMMUTE...THOUGHT IT PRUDENT TO INCLUDE SEDGWICK AND SUMNER COUNTIES IN A WINTER WEATHER ADVISORY...WHERE ICE ACCUMULATIONS MAY APPROACH ONE-EIGHTH OF AN INCH. KLEINSASSER PREV DISCUSSION... /ISSUED 606 PM CST SUN FEB 10 2008/ AVIATION... 00Z TAFS...ICT/SLN/HUT/CNU/RSL...CHALLENGING TAF FORECAST...WITH LOW CLOUDS AND FREEZING RAIN MOVING IN TOWARD 09-10Z (3-4AM)...AS LOW-LEVEL ISENTROPIC ASCENT AND MOISTURE TRANSPORT COMMENCE IN ASSOCIATION WITH 40-50 KT SOUTH/SOUTHWESTERLY LOW-LEVEL JET. THE BEST POTENTIAL FOR FREEZING RAIN WILL OCCUR GENERALLY EAST OF THE TURNPIKE...AND IT APPEARS IMMINENT FOR FAR SOUTHEAST KANSAS. ELEVATED INSTABILITY PER MODEL SOUNDINGS WILL BE APPROACHING 500-700 J/KG...SO THERE WILL BE A FEW EMBEDDED THUNDERSTORMS OVER SOUTHEAST KANSAS...WHICH WILL AID IN ICE ACCUMULATIONS. WITH LOSS OF INSTABILITY...FREEZING RAIN SHOULD TRANSITION TO FREEZING DRIZZLE BY AFTERNOON OVER SOUTHEAST KANSAS. HOWEVER...STRENGTHENING SOUTHERLY FLOW MAY BE ENOUGH TO WARM TEMPERATURES TO ABOVE FREEZING BY EARLY AFTERNOON...AND CHANGE THE PRECIPITATION TYPE TO DRIZZLE. ALL IN ALL...SOUTHEAST KANSAS COULD SEE ICE ACCUMULATIONS BETWEEN 1/4 AND 1/2 INCH. KLEINSASSER PREV DISCUSSION... /ISSUED 252 PM CST SUN FEB 10 2008/ DISCUSSION... MAIN FORECAST CONCERN...POTENTIAL FOR SIGNIFICANT ICING LATE TONIGHT INTO MONDAY ACROSS SOUTHEAST KANSAS. TONIGHT-MONDAY: ARCTIC AIR NOW WELL ENTRENCHED ACROSS KANSAS...WITH TEMPS IN OUR AREA REMAINING BELOW FREEZING THIS PM ALONG WITH DEWPOINTS IN THE SINGLE DIGITS. GFS/UKMET/NAM-WRF SUPPORT POTENTIAL FOR SIGNIFICANT ICE ACCUMULATIONS FOR SERN KS FOR LATE TONIGHT-MONDAY. IMPRESSIVE ISENTROPIC LIFT ALONG WITH MOISTURE TRANSPORT IN ASSOCIATION WITH 45-50 KT SWRLY LOW-LEVEL JET WILL RESULT IN SATURATION OF THE WARM LAYER ALOFT THRU 750 MB...WITH ELEVATED INSTABILITY EVIDENT ON FORECAST SOUNDINGS. THIS SHOULD ALLOW LIGHT FREEZING RAIN TO DEVELOP BY DAYBREAK AND BECOME WIDESPREAD ACROSS SERN KS. THE INSTABILITY ALSO SUPPORTS CONVECTIVE ELEMENTS AND LOCALLY HEAVIER FREEZING RAIN. QPF OF AROUND 0.20 TO 0.30 ON THE GFS/WRFARW32 ALONG WITH LOCALLY HEAVIER AMOUNTS IN CONVECTION SUPPORT UPGRADING MOST OF THE WINTER STORM WATCH TO A WARNING WITH THIS PACKAGE. THE NWRN-MOST COUNTIES OF THE WATCH (FLINT HILLS) WILL BE PUT IN A WINTER WX ADVISORY...WHERE MORE CONFIDENT FREEZING RAIN AMOUNTS WILL BE LESS THAN ONE-QUARTER INCH. IT IS QUITE POSSIBLE THAT LATER SHIFTS MAY NEED TO EXPAND THE WINTER WX ADVISORY WWD INTO THE WICHITA METRO AREA FOR MONDAY MORNING (INCLUDING RUSH HOUR). FAR SERN KS WILL REMAIN UNDER CLOUDS/PRECIPITATION THE LONGEST INTO MONDAY AND THEREFORE HIGHS MAY STRUGGLE TO GET TO FREEZING UNTIL LATE IN THE DAY IF AT ALL. SO EXTENDING THE WARNING TIL 21Z MON. THE DEEPER MOISTURE IS PROGGED TO GET SHUNTED EWD MON NIGHT AS THE UPPER TROF/MID LEVEL CAA ARRIVE. SO ALTHOUGH THE PRECIPITATION MAY BRIEFLY TRANSITION TO FROZEN FORM BEFORE ENDING...PRECIPITATION CHANCES ARE EXPECTED TO WIND DOWN RAPIDLY FROM W-E ACROSS OUR AREA. TUESDAY-WEDNESDAY: DRY WEATHER EXPECTED AS THE UPPER TROF MOVES EAST OF OUR AREA...WITH THE NEXT STRONG UPPER TROF/LOW DIGGING TOWARD THE SOUTHWESTERN STATES. NEAR NORMAL TEMPERATURES PROGGED TUESDAY. THEN TEMPERATURES WILL WARM TO ABOVE NORMAL READINGS WED-WED NIGHT AS PRESSURE FALLS TO THE LEE OF THE ROCKIES INDUCE A STRONG SOUTHERLY COMPONENT WITH A LOW-LEVEL THERMAL RIDGE BUILDING INTO THE AREA AHEAD OF THE NEXT ARCTIC FRONT. THURSDAY-SUNDAY: REGARDING THE SOUTHERN STREAM UPPER LOW EJECTION FROM THE SOUTHERN ROCKIES ACROSS THE SOUTHERN PLAINS...PREFER THE 00Z ECMWF OVER THE LATEST GFS. DPROG/DT ANALYSIS INDICATES THE GFS HAS POOR CONTINUITY WITH THIS FEATURE CENTERED ON FRI...WITH THE ECMWF SHOWING BETTER CONTINUITY ON POSITIONING AND MAINTAINING AN UPPER LOW. BOTH MODELS DO AGREE THAT THE ARCTIC FRONT WILL PLUNGE SEWD THRU OUR AREA THURS/THURS EVE WITH MUCH COLDER AIR ARRIVING. LOWERED HIGHS FRI SUBSTANTIALLY GIVEN LATEST MODEL TRENDS. THERE WILL BE A CHANCE (~30%) OF MIXED WINTRY PRECIPITATION WITH BOTH THE ARCTIC FRONT MOVING THRU...AND WITH THE UPPER LOW TRACKING BY TO OUR S ACROSS OK/TX. THE LAST HALF OF THE WEEKEND SHOULD BE DRY AND NEAR NORMAL TEMPS. JMC && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 17 38 25 43 / 30 60 20 10 HUTCHINSON 16 39 23 43 / 20 30 20 10 NEWTON 16 37 24 42 / 20 40 20 10 ELDORADO 16 36 24 42 / 30 60 30 10 WINFIELD-KWLD 19 38 27 43 / 50 70 40 10 RUSSELL 15 39 21 44 / 10 20 10 0 GREAT BEND 16 41 22 44 / 10 20 10 0 SALINA 14 36 23 43 / 10 30 20 0 MCPHERSON 15 38 23 43 / 10 30 20 10 COFFEYVILLE 19 34 28 41 / 50 80 50 10 CHANUTE 16 33 26 40 / 50 80 50 10 IOLA 16 33 25 40 / 40 80 50 10 PARSONS-KPPF 18 34 27 40 / 50 80 50 10 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM CST MONDAY FOR KSZ053- 069-070-083-092-093. WINTER STORM WARNING FROM 4 AM TO 3 PM CST MONDAY FOR KSZ071-072- 094>096-098>100. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 552 AM CST MON FEB 11 2008 .DISCUSSION... MAIN FORECAST CONCERN REMAINS THE WINTRY MIX OF PRECIPITATION EXPECTED ACROSS THE REGION THROUGH THE NEXT 24 HOURS. LATEST FORECAST MODELS HAVE COME INTO BETTER AGREEMENT ON THE ANTICIPATED WINTER WEATHER SCENARIO...BUT DIFFERENCES STILL REMAIN. THE GFS IS STILL THE WARMEST MODEL...ESPECIALLY TONIGHT WHEN IT WARMS SURFACE TEMPERATURES ABOVE FREEZING OVER A LARGE PART OF THE AREA. THE NAM REMAINS THE COLDER MODEL...WITH SURFACE TEMPERATURES REMAINING AT OR BELOW FREEZING OVER ALL BUT MOST OF WESTERN KENTUCKY TONIGHT. REALITY WILL PROBABLY LIE SOMEWHERE IN BETWEEN... SO WE DECIDED TO USE A BLEND OF THE GFS AND NAM FOR THIS FORECAST PACKAGE. LATEST RADAR IMAGERY INDICATES PRECIPITATION ALREADY OVERSPREADING SOUTHERN PORTIONS OF MISSOURI. THIS TREND WILL CONTINUE AS A STORM SYSTEM OVER THE SOUTHERN PLAINS TRACKS NORTHEAST TOWARDS THE LOWER OHIO VALLEY TONIGHT. AS THE PRECIPITATION BEGINS TO SPREAD INTO THE AREA...TEMPERATURE PROFILES INDICATE IT WILL BE COLD ENOUGH TO START OUT AS SNOW OR SLEET OVER NORTHERN PORTIONS OF SOUTHEAST MISSOURI... SOUTHERN ILLINOIS...AND SOUTHWEST INDIANA LATE THIS MORNING INTO THIS AFTERNOON. FARTHER SOUTH...A MIX OF SLEET AND FREEZING RAIN IS EXPECTED OVER THE REST OF SOUTHEAST MISSOURI...SOUTHERN ILLINOIS... INTO PORTIONS OF WESTERN KENTUCKY. SIGNIFICANT SNOW AND ICE ACCUMULATION IS EXPECTED OVER MUCH OF THE FORECAST AREA. AS A RESULT...WE EXPANDED THE WINTER STORM WARNING TO INCLUDE ALL AREAS ALONG AND NORTH OF A LINE FROM POPLAR BLUFF MISSOURI TO PADUCAH AND CALHOUN KENTUCKY. A CORE OF SIGNIFICANT ICING IS MOST LIKELY FROM PERRYVILLE MISSOURI EAST ACROSS THE ILLINOIS ROUTE 13 CORRIDOR FROM CARBONDALE TO HARRISBURG...THEN TO EVANSVILLE INDIANA...WHERE A GLAZE OF ONE HALF INCH OF ICE MAY ACCUMULATE BY LATE TONIGHT. FARTHER NORTH NEAR THE INTERSTATE 64 CORRIDOR IN SOUTHERN ILLINOIS AND SOUTHWEST INDIANA...MAINLY SNOW IS EXPECTED...WITH THE POTENTIAL FOR ACCUMULATIONS OF 4 INCHES OR MORE. THE ONE FACTOR THAT COULD REALLY IMPACT THESE VALUES EVEN MORE IS THE IMPACT OF CONVECTION. SPC CONTINUES TO HAVE MUCH OF THE FORECAST AREA IN GENERAL THUNDER FOR LATER TODAY AND TONIGHT. WE ADDED A MENTION OF THUNDER TO MAINLY SOUTHERN PORTIONS OF THE AREA LATE THIS AFTERNOON AND TONIGHT GIVEN THE ONGOING CONVECTION ALREADY TAKING PLACE OVER SOUTHEAST KANSAS INTO SOUTHWEST MISSOURI. GENERALLY USED THE RUC13 TEMPERATURES THIS MORNING...WITH A BLEND OF NAM AND GFS GUIDANCE THIS AFTERNOON INTO TUESDAY. WE MADE NO CHANGES TO THE FORECAST BEYOND TUESDAY NIGHT. && .AVIATION... WINDS OVER THE NEXT 24 HOURS WILL BE PRIMARILY FROM THE EAST AS LOW PRESSURE APPROACHES FROM THE SOUTHERN PLAINS. WINTRY PRECIPITATION WILL OVERSPREAD AREA FORECAST TERMINALS LATE THIS MORNING AND THIS AFTERNOON...WITH SIGNIFICANT ICING POSSIBLE FROM KCGI AND KPAH TO KEVV AND KOWB THIS AFTERNOON AND TONIGHT. VFR CEILINGS WILL LOWER TO MVFR AS THE PRECIPITATION INCREASES IN INTENSITY THIS EVENING... AND MAY EVEN TEETER ON IFR CONDITIONS FOR BRIEF INTERVALS OVERNIGHT. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST TUESDAY FOR BALLARD-CRITTENDEN-DAVIESS-HENDERSON-LIVINGSTON-MCCRACKEN- MCLEAN-UNION KY-WEBSTER. MO...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR BOLLINGER-BUTLER- CAPE GIRARDEAU-CARTER-PERRY MO-RIPLEY-SCOTT-STODDARD-WAYNE MO. IL...WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST TUESDAY FOR EDWARDS-FRANKLIN-GALLATIN-HAMILTON-HARDIN-JEFFERSON-JOHNSON- MASSAC-POPE-PULASKI-SALINE-WABASH-WAYNE IL-WHITE-WILLIAMSON. WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR ALEXANDER- JACKSON-PERRY IL-UNION IL. IN...WINTER STORM WARNING FROM NOON TODAY TO 6 AM CST TUESDAY FOR GIBSON-PIKE-POSEY-SPENCER-VANDERBURGH-WARRICK. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 643 PM EST TUE FEB 12 2008 .SYNOPSIS... COMPLEX WEATHER PATTERN OVER THE REGION WITH WAVES OF LOW PRESSURE WILL FORM A DOMINANT AREA OF LOW PRESSURE BY WEDNESDAY AFTERNOON OVER EASTERN NORTH CAROLINA. WARMER AIR RIDING OVER SHALLOW COLD AIR WILL GIVE WAY TO BOUTS OF FREEZING PRECIPITATION. FREEZING RAIN IS EXPECTED TO SLOWLY CHANGE TO RAIN BY WED MORNING FROM SOUTH TO NORTH. THE NEW LOW THAT IS EXPECTED TO DEVELOP OVER EASTERN NORTH CAROLINA COULD PRODUCE A FEW INCHES OF SNOW BEFORE THE PRECIPITATION ENDS WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE REGION THURSDAY AND FRIDAY. A MORE SIGNIFICANT RAIN STORM MAY IMPACT THE REGION LATE SUNDAY INTO MONDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... HEADS UP...ICE STORM WARNING GOING UP FOR AREA EAST OF THE BLUE RIDGE INCLUDING WASHINGTON DC/BALTIMORE MD AND CHARLOTTESVILLE. UPDATED WSW OUT SHORTLY. COUNTIES NOT IN THE ICE STORM WARNING THAT ARE EAST OF THE BLUE RIDGE INCLUDE NELSON AND KING GEORGE VIRGINIA AND CALVERT MARYLAND WHICH WILL REMAIN IN A WINTER WEATHER ADVISORY...AND ST. MARYS COUNTY MARYLAND WHICH WILL REMAIN WITHOUT ANY WARNING/ADVISORY. TEMPERATURE PROFILES FROM LATEST NAM/RUC AND LOCAL MODELS FOR DC/BALT REGION...AND QPF POTENTIAL OF UP TO ONE HALF INCH EAST OF THE BLUE RIDGE...SEE POTENTIAL FOR ONE QUARTER OF AN INCH OF ICING. COORDINATION WITH NCEP/HPC IN AGREEMENT WITH THIS UPGRADE. FORECAST IN PROCESS OF BEING UPDATED NOW. DETAILS IN THIS DICUSSION LATER. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... THE QUESTION MARK FOR TONIGHT IS HOW MUCH PRECIPITATION WILL FALL OVERNIGHT. IF THERE ENDS UP BEING MORE PRECIP...AN ICE STORM WARNING MAY BE REQUIRED FOR EASTERNMOST WV AND WEST CENTRAL MD AT SOME POINT IN THE FUTURE. THEY CERTAINLY DO NOT LOOK LIKE THEY WILL BREAK FREEZING FOR QUITE SOME TIME. IF THERE IS LESSER PRECIP...THE ADVISORY WITH 1 TO 2 TENTHS OF AN INCH OF ICE SHOULD HOLD. AM EXPECTING ALL RAIN AT 7AM WED WITH OVC SKIES AND A THERMOCLINE OVER THE AREA BETWEEN 33 IN WEST CENTRAL MD TO MID 40S IN LOWER S MD. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... WAVES OF LOW PRES WILL MOVE ACROSS THE REGION DURING THE NEXT 36 HRS KEEPING THE THREAT FOR PRECIP. MOISTURE WILL BE PLENTIFUL WITH 1.25+ PWATS AND FAVORABLE DYNAMICS FOR DECENT AMT OF PRECIP. TEMPS WED MORNING SHOULD BE WELL ABOVE FREEZING FOR ALL RAIN MOST OF THE DAY. 12Z GFS AND 12Z ECMWF COMING INTO BETTER AGREEMENT THAT UPPER TROUGH COMING FROM THE MIDWEST WILL CLOSE OFF AS IT TRAVERSES THE AREA. THIS WILL RESULT IN ANOTHER AREA OF LOW PRES AND FRONTAL ZONE DEVELOPING OVR ERN NC. COLD POOL MOVING OVERHEAD AND STRONG VERTICAL MOTION WILL LEAD TO PRECIP CHANGING BACK TO SNOW BEFORE IT ENDS. 12Z GFS SHOWS INDICATES A HEAVY BURST OF SNOW IS POSSIBLE FOR AREAS ALONG THE INTERSTATE 95. 1 TO 3 INCHES OF SNOW ARE POSSIBLE TOMORROW NIGHT BEFORE PRECIP MOVES OFFSHORE EARLY THU MORNING. ANOTHER ADVISORY MAY BE REQUIRED LATE TOMORROW. THINGS QUIET DOWN THU-FRI WITH ANOTHER CHANCE OF SOME PRECIP FRI NIGHT. A MORE SIG STORM WILL LIKELY AFFECT THE AREA LATE SUN INTO MONDAY AS PHASING OF BOTH NRN AND SRN STREAM OCCURS OVER THE MIDDLE OF THE COUNTRY. THE MORE RELIABLE EUROPEAN SOLUTION INDICATES A TRACK WELL TO THE NORTHWEST OF THE AREA FOR ALL RAIN BUT THE GFS SUGGEST A SIG WINTER PRECIP FOR FAR WRN MD AND POINTS NORTH. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... OVERCAST 040 FOR MOST OF THE TAF SITES WILL GRADUALLY LOWER AS PRECIP DEVELPS. THAT WILL BE IN THE FORM OF WINTERY MIX MID AFTERNOON...ZR LATE AFTERNOON...THEN CHANGING TO RAIN FROM S TO N DURING THE LATE AFTERNOON AND OVERNIGHT. HGR AND MRB MAY NOT CHANGE TO RAIN UNTIL 12Z WED. LIFR CONDITIONS ON WED SLOWLY IMPROVING TO VFR WED NIGHT. NO SIG WEATHER EXPECTED THU AND FRI. NEXT SIG STORM LATE SUN AND MON WITH RAIN MOST LIKELY. && .MARINE... WINDS OF 15 TO 20 KT ON MOST OF THE BAY AND LOWER TIDAL POTOMAC FROM TIME TO TIME WILL REQUIRE THE SMALL CRAFT ADV TO BE CONTINUED UNTIL 10Z EARLY WED MORNING. SCA EXPECTED WED NIGHT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...ICE STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR DCZ001. MD...ICE STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR MDZ004>007- 009>011-013-014-016. WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MDZ003- 018-501-502. VA...ICE STORM WARNING UNTIL 7 AM EST WEDNESDAY FOR VAZ037>042- 050>056. WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR VAZ021- 025>031-036-057. WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR WVZ050>055-501>504. MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST WEDNESDAY FOR ANZ531>534- 537. SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 9 AM EST THURSDAY FOR ANZ530>537. && $$ SYNOPSIS...LFR NEAR TERM...BJL/BPP/LFR/SMZ SHORT TERM...CAS LONG TERM...LFR AVIATION...LFR/CAS MARINE...LFR/CAS md AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1025 PM EST TUE FEB 12 2008 .UPDATE... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SHORTWAVE HEADING ENE THRU LWR MI WHILE NEXT SHORTWAVE IS DROPPING SE THRU MANITOBA INTO NRN ONTARIO. PATCHY -SN/FLURRIES ASSOCIATED WITH LWR MI SHORTWAVE SHOULD EXIT THE ERN FCST AREA IN THE NEXT COUPLE OF HRS. ATTENTION THEN TURNS TO THE COLD FRONT EXTENDING FROM NRN ONTARIO THRU FAR NW MN...ASSOCIATED WITH UPSTREAM SHORTWAVE. KDLH RADAR AND SFC OBS INDICATED -SN/FLURRIES AHEAD OF FRONT IN NRN MN. THE -SN IS OCCURRING IN A NARROW RIBBON WEAK DEEP LAYER QVECTOR CONVERGENCE AND MOIST ISENTROPIC ASCENT (280K THETA SFC) PER 00Z RUC. AS FORCING AND ISENTROPIC ASCENT SPREAD E OVERNIGHT...850MB TEMPS AROUND -14C WILL BE PLENTY COLD ENOUGH TO SUPPORT LAKE ENHANCEMENT AS THE COLD FRONT CROSSES WRN LAKE SUPERIOR. PER 00Z RUC/NAM...FRONT SHOULD REACH THE KEWEENAW IN THE 10-12Z TIME FRAME. EXPECT A BRIEF BURST OF MDT/HVY SNOW WITH FROPA. CERTAINLY COULD SEE A QUICK 1-3 INCHES OF ACCUMULATION...ESPECIALLY WITH FAVORABLE DENDRITIC SNOW GROWTH TEMPS IN THE LAYER OF ASCENT. CONSIDERED AN ADVY AS LATE NIGHT THRU WED MORNING SNOW ACCUMULATIONS ON THE KEWEENAW MAY APPROACH ADVY LEVELS. HOWEVER...SINCE INVERSION WILL BE CRASHING QUICKLY TO 3.5-4KFT BEHIND FRONT...WILL HOLD OFF AN ADVY FOR NOW. TO THE E...INCREASED POPS TO LIKELY FOR ALGER/LUCE WED AFTN UNDER NW FLOW BEHIND COLD FRONT. && .PREV DISCUSSION (ISSUED AT 416 PM EST)... SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM CA INTO THE NRN ROCKIES/ALBERTA AND A TROUGH FROM CNTRL CANADA INTO THE MS VALLEY. A SHORTWAVE FROM SW WI INTO ERN IA SUPPORTED AN AREA OF LIGHT SNOW FROM ERN WI INTO SRN UPPER MI. AN UPSTREAM SHORTWAVE WAS MOVING SE THROUGH SRN MANITOBA. 700-500 QVECTOR CONV AND 280K ISENTROPIC LIFT ASSOCIATED WITH THIS FEATURE ALSO HAS PRODUCED SOME LIGHT SNOW WITH VSBY INTO THE 1-3SM RANGE AHEAD OF SFC COLD FRONT. SHORT TERM (TONIGHT AND WED)... MAIN FCST CONCERNS ARE LIGHT SNOW CHANCES SE THIS EVENING AND LES INTO NW UPPER MI LATE TONIGHT INTO WED. EXPECT LIGHT SNOW WITH THE WI SHORTWAVE WILL BRUSH THE SE PORTION OF THE CWA LATE THIS AFTERNOON AND EARLY EVENING. RADAR AND UPSTREAM OB TRENDS SUGGEST THAT ANY ACCUMULATIONS SHOULD BE MINIMAL...LESS THAN A HALF INCH. WINDS SHOULD BACK ENOUGH TO THE NE TO REDUCE CHANCES FOR LES OR LAKE ENHANCED SNOW OFF OF LAKE MI. LATE TONIGHT THE SHORTWAVE AND SFC FRONT WILL MOVE INTO WRN LAKE SUPERIOR WITH WINDS VEERING FROM SW TO WNW AROUND 12Z. 850 MB TEMPS TO AROUND -15C BY 12Z SHOULD SUPPORT INCREASING LES POTENTIAL INTO NW UPPER MI. SNOW GROWTH PARAMETERS ARE FAVORABLE BTWN 09Z-15Z WITH THE 2K-8K FT LAYER IN THE -12C TO -17C RANGE. HOWEVER...THE PERIOD OF BEST LOW LEVEL CONV IS RELATIVELY BRIEF AND THE DEEPER MOISTURE MOVES OUT BEFORE THE COLDER AIR ARRIVES. VERY DRY AIR MOVING IN BY MIDDAY ALONG WITH A SHORTER FETCH AS WINDS VEER NW AND INVERSION HEIGHTS FALLING TO AROUND 4K FT...SHOULD DECREASE SNOWFALL RATES/COVERAGE WITH MAINLY SCT -SHSN/FLURRIES BY AFTERNOON. WRLY WINDS JUST BRUSHING THE SHORELINE E OF MUNISING WILL VEER NW IN THE AFTERNOON. AGAIN...BY THAT TIMES...SIGNIFICANT DRY ADVECTION AND LOWERING INVERSION HEIGHTS WILL LIMIT LES POTENTIAL WITH ONLY LIGHT ACCUMULATIONS. LONG TERM (WED NIGHT THRU TUE)... AS POINTED OUT BY HPC...ECMWF IS THE PREFERRED SOLUTION THROUGH THE EXTENDED. THE MID LEVEL LOW OVER NORTHERN ONTARIO WILL MOVE OVER NORTHERN ONTARIO WEDNESDAY NIGHT AS A WEAK SHORTWAVE WRAPPING AROUND THIS LOW SWEEPS INTO THE NORTHERN PLAINS. A SURFACE LOW ASSOCIATED WITH THIS SHORTWAVE WILL DEEPEN OVER THE CENTRAL PLAINS. THE ACCOMPANYING COLD FRONT WILL MOVE SOUTHEAST OVERNIGHT STRETCHING FROM SOUTHEAST ONTARIO THROUGH NORTHERN LOWER MICHIGAN TO THE LOW OVER THE TEXAS PANHANDLE. CONSIDERABLE AMOUNT OF LOW LEVEL MOISTURE WILL MOVE INTO THE AREA AHEAD OF THE LOW. THE STRONGEST ISENTROPIC ASCENT WILL STILL BE OVER WISCONSIN. THE MID LEVEL LOW WILL LIFT INTO SOUTHEAST HUDSON BAY DIRECTING A SHORTWAVE THROUGH THE U.P. ON THURSDAY. THE SURFACE LOW WILL MOVE INTO NORTHERN WISCONSIN. WINDS SHOULD DECREASE OVER THE FORECAST IN THE CLOSE PROXIMITY OF THE LOW. GUIDANCE SHOWING THE DEEPEST MOISTURE WILL BE TO THE SOUTH OF THE FORECAST AREA. DELTA-T`S WILL AROUND -23C. PLAN TO GO WITH A WATCH FOR MOST OF THE SOUTHERN COUNTIES AS THIS WILL BE CLOSEST TO THE DEEPEST MOISTURE FIELD AND THE AREA OF STRONGEST 850-500MB Q-VECTORS CONVERGENCE DURING THE DAY. AFTER THE SURFACE LOW SETTLE INTO LOWER MICHIGAN ON THURSDAY...THE WINDS WILL BECOME MORE NORTHERLY. THE SURFACE RIDGE WILL SWEEP INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THUS LOOKING FOR LES TO DEVELOP OVER THE WESTERN U.P. AND EAST OF MUNISING AGAIN THURSDAY NIGHT. THE MID LEVEL CLOSED LOW WILL SHIFT INTO WEST CENTRAL QUEBEC AS A WEAK SHORTWAVE RACE ACROSS THE FORECAST AREA. THE SURFACE WINDS WILL BACK WEST ON FRIDAY AS THE RIDGE DESCENDS ON THE UPPER GREAT LAKES. THE DELTA-T`S WILL BE AROUND 20C. WINDS WILL CONTINUE TO BACK TO THE WEST. THUS THE LAKE EFFECT SNOWS WILL END AS THE RIDGE MOVES THROUGH. THE LONGWAVE TROUGH WILL SLIDE INTO NEW ENGLAND FRIDAY NIGHT WHILE SURFACE HIGH MOVES INTO THE OHIO RIVER VALLEY AND THE LOWER GREAT LAKES. WINDS WILL BE LIGHT EARLY AND BECOME OUT OF THE SOUTHWEST LATE. THE WATER-850MB DELTA-T`S WILL BE AROUND 20C OVER EASTERN LAKE SUPERIOR TO AROUND 14C OVER THE WEST. STILL BOTH COOL ENOUGH TO GENERATE SOME LAKE EFFECT SNOW. HOWEVER...WITH THE LIGHT WINDS AND WINDS BACKING SOUTHWEST...THE LES WILL SHIFT OUT OF THE U.P. MEANWHILE...A COLD FRONT WILL DEVELOP OVER SOUTH CENTRAL CANADA AND SWEEP INTO NORTHERN MINNESOTA AND WESTERN ONTARIO ON SATURDAY. WEAK ISENTROPIC ASCENT AHEAD OF THE FRONTAL SYSTEM AND LOW LEVEL MOISTURE DRAWN INTO THE AREA WITH THE SOUTHWEST FLOW WILL GENERATE SOME SNOWS OVER THE AREA. SINCE THE WEST END OF THE FORECAST AREA IS STILL FAR ENOUGH AWAY FROM THE FRONT THE CHANCES WILL STILL BE SLIGHT. THE LOW AND ACCOMPANYING COLD FRONT WILL SWEEP INTO THE U.P. SATURDAY NIGHT AND INTO EASTERN ONTARIO ON SUNDAY. MEANWHILE...A TROUGH DEEPENING OVER SOUTH CENTRAL CANADA WILL MOVE OVER WESTERN ONTARIO AND THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY NIGHT AND THROUGH THE U.P. ON SUNDAY. WINDS WILL SHIFT NORTHWEST FOLLOWING THE FROPA. THE CHANCE OF SNOW WILL SPREAD ACROSS THE FORECAST AREA. COLD AIR WILL STREAM INTO THE AREA SUNDAY NIGHT AND MONDAY. A LOW LEVEL THERMAL TROUGH WILL MOVE INTO WESTERN ONTARIO AND THE 850MB TEMPERATURES DROP TO AROUND -20C OVER THE WESTERN LAKE. THIS SHOULD GENERATE LES...MAINLY OVER AREAS PRONE TO LES WITH A NORTHWEST FLOW. THE LONGWAVE TROUGH WILL REMAIN OVER THE UPPER GREAT LAKES REGION THROUGH TUESDAY...CONTINUING TO PULL COLD AIR INTO THE FORECAST AREA. A COLD POOL OF LOW LEVEL AIR WILL BE OVER WESTERN ONTARIO WITH THE THERMAL TROUGH EXTENDING INTO WESTERN LAKE SUPERIOR. 850MB TEMPERATURES WILL LOWER TO -24C OVER THE WESTERN LAKE. LES WILL CONTINUE. HOWEVER...THE VERY COLD AIR WILL BE PARTICULARLY DRY SO DO NOT EXPECT HEAVY SNOWFALL. AT THIS TIME THE MODELS ARE NOT CALLING FOR STRONG WINDS. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... VFR CONDITIONS SHOULD PREVAIL AT KCMX THRU THE EVENING. AS LOW-LEVEL WINDS BEGIN TO TAKE ON AN OVERWATER COMPONENT FROM THE W LATER IN THE NIGHT...MVFR CIGS SHOULD DEVELOP. COLD FRONT WILL PASS LATE TONIGHT/EARLY WED MORNING...BRINGING LAKE EFFECT -SHSN AND MVFR VIS INITIALLY. AROUND THE TIME OF FROPA...EXPECT A PERIOD OF HEAVIER SNOW REDUCING VIS TO LIFR. IFR VIS IN -SHSN MAY THEN CONTINUE WELL INTO THE AFTN BEFORE IMPROVEMENT TO MVFR LATE AS WINDS VEER MORE NRLY (A LESS FAVORABLE DIRECTION FOR LAKE EFFECT -SHSN THERE). AT KSAW...OVERALL...VFR CONDITIONS SHOULD DOMINATE UNTIL WED AFTN. A FEW OBS TO THE W INDICATED SOME MVFR CIGS AT TIMES EARLIER...BUT DIFFICULT TO SEE THOSE CLOUDS ON SATELLITE DUE TO PRESENCE OF HIGHER LEVEL CLOUDS. SINCE THERE HAVE NOT BEEN ANY OBS RECENTLY THAT HAVE INDICATED MVFR...WILL NOT INCLUDE A MENTION OF MVFR THRU THE NIGHT AT KSAW WITH THIS FCST ISSUANCE. FROPA LATE WED MORNING SHOULD BRING MVFR CIGS AND MAYBE A FEW FLURRIES. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRES MOVING THROUGH NRN ONTARIO TO JAMES BAY WILL DRAG A COLD FRONT ACROSS LAKE SUPERIOR LATE TONIGHT AND WED MORNING. SW WINDS ARE EXPECTED TO INCREASE INTO THE 20-30 KT RANGE OVER THE W BY MIDNIGHT AND VEER NW AS THE FRONT MOVES THROUGH. THE WINDS WILL DIMINISH LATE WED INTO WED NIGHT AS A WEAK RIDGE BUILDS INTO THE REGION. LOW PRES MOVING TOWARD THE SOUTHERN GREAT LAKES THU WILL BRING AN INCREASE IN N WINDS TO 15 TO 25 KT. OTHERWISE...WINDS SHOULD REMAIN BLO 30 KT UNTIL A STRONGER LOW PRESSURE SYSTEM MOVES EASTWARD THROUGH NRN ONTARIO OR LAKE SUPERIOR LATE SATURDAY INTO SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH LATE WED NIGHT THRU THU EVENING MIZ010>013. && $$ UPDATE...ROLFSON SHORT TERM...JLB LONG TERM...DLG AVIATION...ROLFSON MARINE...JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 627 PM EST TUE FEB 12 2008 UPDATED AVIATION DISCUSSION FOR 00Z TAFS .SYNOPSIS (ISSUED AT 416 PM EST)... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM CA INTO THE NRN ROCKIES/ALBERTA AND A TROUGH FROM CNTRL CANADA INTO THE MS VALLEY. A SHORTWAVE FROM SW WI INTO ERN IA SUPPORTED AN AREA OF LIGHT SNOW FROM ERN WI INTO SRN UPPER MI. AN UPSTREAM SHORTWAVE WAS MOVING SE THROUGH SRN MANITOBA. 700-500 QVECTOR CONV AND 280K ISENTROPIC LIFT ASSOCIATED WITH THIS FEATURE ALSO HAS PRODUCED SOME LIGHT SNOW WITH VSBY INTO THE 1-3SM RANGE AHEAD OF SFC COLD FRONT. && .SHORT TERM (TONIGHT AND WED ISSUED AT 416 PM EST)... MAIN FCST CONCERNS ARE LIGHT SNOW CHANCES SE THIS EVENING AND LES INTO NW UPPER MI LATE TONIGHT INTO WED. EXPECT LIGHT SNOW WITH THE WI SHORTWAVE WILL BRUSH THE SE PORTION OF THE CWA LATE THIS AFTERNOON AND EARLY EVENING. RADAR AND UPSTREAM OB TRENDS SUGGEST THAT ANY ACCUMULATIONS SHOULD BE MINIMAL...LESS THAN A HALF INCH. WINDS SHOULD BACK ENOUGH TO THE NE TO REDUCE CHANCES FOR LES OR LAKE ENHANCED SNOW OFF OF LAKE MI. LATE TONIGHT THE SHORTWAVE AND SFC FRONT WILL MOVE INTO WRN LAKE SUPERIOR WITH WINDS VEERING FROM SW TO WNW AROUND 12Z. 850 MB TEMPS TO AROUND -15C BY 12Z SHOULD SUPPORT INCREASING LES POTENTIAL INTO NW UPPER MI. SNOW GROWTH PARAMETERS ARE FAVORABLE BTWN 09Z-15Z WITH THE 2K-8K FT LAYER IN THE -12C TO -17C RANGE. HOWEVER...THE PERIOD OF BEST LOW LEVEL CONV IS RELATIVELY BRIEF AND THE DEEPER MOISTURE MOVES OUT BEFORE THE COLDER AIR ARRIVES. VERY DRY AIR MOVING IN BY MIDDAY ALONG WITH A SHORTER FETCH AS WINDS VEER NW AND INVERSION HEIGHTS FALLING TO AROUND 4K FT...SHOULD DECREASE SNOWFALL RATES/COVERAGE WITH MAINLY SCT -SHSN/FLURRIES BY AFTERNOON. WRLY WINDS JUST BRUSHING THE SHORELINE E OF MUNISING WILL VEER NW IN THE AFTERNOON. AGAIN...BY THAT TIMES...SIGNIFICANT DRY ADVECTION AND LOWERING INVERSION HEIGHTS WILL LIMIT LES POTENTIAL WITH ONLY LIGHT ACCUMULATIONS. .LONG TERM (WED NIGHT THRU TUE)... AS POINTED OUT BY HPC...ECMWF IS THE PREFERRED SOLUTION THROUGH THE EXTENDED. THE MID LEVEL LOW OVER NORTHERN ONTARIO WILL MOVE OVER NORTHERN ONTARIO WEDNESDAY NIGHT AS A WEAK SHORTWAVE WRAPPING AROUND THIS LOW SWEEPS INTO THE NORTHERN PLAINS. A SURFACE LOW ASSOCIATED WITH THIS SHORTWAVE WILL DEEPEN OVER THE CENTRAL PLAINS. THE ACCOMPANYING COLD FRONT WILL MOVE SOUTHEAST OVERNIGHT STRETCHING FROM SOUTHEAST ONTARIO THROUGH NORTHERN LOWER MICHIGAN TO THE LOW OVER THE TEXAS PANHANDLE. CONSIDERABLE AMOUNT OF LOW LEVEL MOISTURE WILL MOVE INTO THE AREA AHEAD OF THE LOW. THE STRONGEST ISENTROPIC ASCENT WILL STILL BE OVER WISCONSIN. THE MID LEVEL LOW WILL LIFT INTO SOUTHEAST HUDSON BAY DIRECTING A SHORTWAVE THROUGH THE U.P. ON THURSDAY. THE SURFACE LOW WILL MOVE INTO NORTHERN WISCONSIN. WINDS SHOULD DECREASE OVER THE FORECAST IN THE CLOSE PROXIMITY OF THE LOW. GUIDANCE SHOWING THE DEEPEST MOISTURE WILL BE TO THE SOUTH OF THE FORECAST AREA. DELTA-T`S WILL AROUND -23C. PLAN TO GO WITH A WATCH FOR MOST OF THE SOUTHERN COUNTIES AS THIS WILL BE CLOSEST TO THE DEEPEST MOISTURE FIELD AND THE AREA OF STRONGEST 850-500MB Q-VECTORS CONVERGENCE DURING THE DAY. AFTER THE SURFACE LOW SETTLE INTO LOWER MICHIGAN ON THURSDAY...THE WINDS WILL BECOME MORE NORTHERLY. THE SURFACE RIDGE WILL SWEEP INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THUS LOOKING FOR LES TO DEVELOP OVER THE WESTERN U.P. AND EAST OF MUNISING AGAIN THURSDAY NIGHT. THE MID LEVEL CLOSED LOW WILL SHIFT INTO WEST CENTRAL QUEBEC AS A WEAK SHORTWAVE RACE ACROSS THE FORECAST AREA. THE SURFACE WINDS WILL BACK WEST ON FRIDAY AS THE RIDGE DESCENDS ON THE UPPER GREAT LAKES. THE DELTA-T`S WILL BE AROUND 20C. WINDS WILL CONTINUE TO BACK TO THE WEST. THUS THE LAKE EFFECT SNOWS WILL END AS THE RIDGE MOVES THROUGH. THE LONGWAVE TROUGH WILL SLIDE INTO NEW ENGLAND FRIDAY NIGHT WHILE SURFACE HIGH MOVES INTO THE OHIO RIVER VALLEY AND THE LOWER GREAT LAKES. WINDS WILL BE LIGHT EARLY AND BECOME OUT OF THE SOUTHWEST LATE. THE WATER-850MB DELTA-T`S WILL BE AROUND 20C OVER EASTERN LAKE SUPERIOR TO AROUND 14C OVER THE WEST. STILL BOTH COOL ENOUGH TO GENERATE SOME LAKE EFFECT SNOW. HOWEVER...WITH THE LIGHT WINDS AND WINDS BACKING SOUTHWEST...THE LES WILL SHIFT OUT OF THE U.P. MEANWHILE...A COLD FRONT WILL DEVELOP OVER SOUTH CENTRAL CANADA AND SWEEP INTO NORTHERN MINNESOTA AND WESTERN ONTARIO ON SATURDAY. WEAK ISENTROPIC ASCENT AHEAD OF THE FRONTAL SYSTEM AND LOW LEVEL MOISTURE DRAWN INTO THE AREA WITH THE SOUTHWEST FLOW WILL GENERATE SOME SNOWS OVER THE AREA. SINCE THE WEST END OF THE FORECAST AREA IS STILL FAR ENOUGH AWAY FROM THE FRONT THE CHANCES WILL STILL BE SLIGHT. THE LOW AND ACCOMPANYING COLD FRONT WILL SWEEP INTO THE U.P. SATURDAY NIGHT AND INTO EASTERN ONTARIO ON SUNDAY. MEANWHILE...A TROUGH DEEPENING OVER SOUTH CENTRAL CANADA WILL MOVE OVER WESTERN ONTARIO AND THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY NIGHT AND THROUGH THE U.P. ON SUNDAY. WINDS WILL SHIFT NORTHWEST FOLLOWING THE FROPA. THE CHANCE OF SNOW WILL SPREAD ACROSS THE FORECAST AREA. COLD AIR WILL STREAM INTO THE AREA SUNDAY NIGHT AND MONDAY. A LOW LEVEL THERMAL TROUGH WILL MOVE INTO WESTERN ONTARIO AND THE 850MB TEMPERATURES DROP TO AROUND -20C OVER THE WESTERN LAKE. THIS SHOULD GENERATE LES...MAINLY OVER AREAS PRONE TO LES WITH A NORTHWEST FLOW. THE LONGWAVE TROUGH WILL REMAIN OVER THE UPPER GREAT LAKES REGION THROUGH TUESDAY...CONTINUING TO PULL COLD AIR INTO THE FORECAST AREA. A COLD POOL OF LOW LEVEL AIR WILL BE OVER WESTERN ONTARIO WITH THE THERMAL TROUGH EXTENDING INTO WESTERN LAKE SUPERIOR. 850MB TEMPERATURES WILL LOWER TO -24C OVER THE WESTERN LAKE. LES WILL CONTINUE. HOWEVER...THE VERY COLD AIR WILL BE PARTICULARLY DRY SO DO NOT EXPECT HEAVY SNOWFALL. AT THIS TIME THE MODELS ARE NOT CALLING FOR STRONG WINDS. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... VFR CONDITIONS SHOULD PREVAIL AT KCMX THRU THE EVENING. AS LOW-LEVEL WINDS BEGIN TO TAKE ON AN OVERWATER COMPONENT FROM THE W LATER IN THE NIGHT...MVFR CIGS SHOULD DEVELOP. COLD FRONT WILL PASS LATE TONIGHT/EARLY WED MORNING...BRINGING LAKE EFFECT -SHSN AND MVFR VIS INITIALLY. AROUND THE TIME OF FROPA...EXPECT A PERIOD OF HEAVIER SNOW REDUCING VIS TO LIFR. IFR VIS IN -SHSN MAY THEN CONTINUE WELL INTO THE AFTN BEFORE IMPROVEMENT TO MVFR LATE AS WINDS VEER MORE NRLY (A LESS FAVORABLE DIRECTION FOR LAKE EFFECT -SHSN THERE). AT KSAW...OVERALL...VFR CONDITIONS SHOULD DOMINATE UNTIL WED AFTN. A FEW OBS TO THE W INDICATED SOME MVFR CIGS AT TIMES EARLIER...BUT DIFFICULT TO SEE THOSE CLOUDS ON SATELLITE DUE TO PRESENCE OF HIGHER LEVEL CLOUDS. SINCE THERE HAVE NOT BEEN ANY OBS RECENTLY THAT HAVE INDICATED MVFR...WILL NOT INCLUDE A MENTION OF MVFR THRU THE NIGHT AT KSAW WITH THIS FCST ISSUANCE. FROPA LATE WED MORNING SHOULD BRING MVFR CIGS AND MAYBE A FEW FLURRIES. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRES MOVING THROUGH NRN ONTARIO TO JAMES BAY WILL DRAG A COLD FRONT ACROSS LAKE SUPERIOR LATE TONIGHT AND WED MORNING. SW WINDS ARE EXPECTED TO INCREASE INTO THE 20-30 KT RANGE OVER THE W BY MIDNIGHT AND VEER NW AS THE FRONT MOVES THROUGH. THE WINDS WILL DIMINISH LATE WED INTO WED NIGHT AS A WEAK RIDGE BUILDS INTO THE REGION. LOW PRES MOVING TOWARD THE SOUTHERN GREAT LAKES THU WILL BRING AN INCREASE IN N WINDS TO 15 TO 25 KT. OTHERWISE...WINDS SHOULD REMAIN BLO 30 KT UNTIL A STRONGER LOW PRESSURE SYSTEM MOVES EASTWARD THROUGH NRN ONTARIO OR LAKE SUPERIOR LATE SATURDAY INTO SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JLB LONG TERM...DLG AVIATION...ROLFSON MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 416 PM EST TUE FEB 12 2008 .SHORT TERM... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM CA INTO THE NRN ROCKIES/ALBERTA AND A TROUGH FROM CNTRL CANADA INTO THE MS VALLEY. A SHORTWAVE FROM SW WI INTO ERN IA SUPPORTED AN AREA OF LIGHT SNOW FROM ERN WI INTO SRN UPPER MI. AN UPSTREAM SHORTWAVE WAS MOVING SE THROUGH SRN MANITOBA. 700-500 QVECTOR CONV AND 280K ISENTROPIC LIFT ASSOCIATED WITH THIS FEATURE ALSO HAS PRODUCED SOME LIGHT SNOW WITH VSBY INTO THE 1-3SM RANGE AHEAD OF SFC COLD FRONT. .SHORT TERM...(TONIGHT AND WEDNESDAY) MAIN FCST CONCERNS ARE LIGHT SNOW CHANCES SE THIS EVENING AND LES INTO NW UPPER MI LATE TONIGHT INTO WED. EXPECT LIGHT SNOW WITH THE WI SHORTWAVE WILL BRUSH THE SE PORTION OF THE CWA LATE THIS AFTERNOON AND EARLY EVENING. RADAR AND UPSTREAM OB TRENDS SUGGEST THAT ANY ACCUMULATIONS SHOULD BE MINIMAL...LESS THAN A HALF INCH. WINDS SHOULD BACK ENOUGH TO THE NE TO REDUCE CHANCES FOR LES OR LAKE ENHANCED SNOW OFF OF LAKE MI. LATE TONIGHT THE SHORTWAVE AND SFC FRONT WILL MOVE INTO WRN LAKE SUPERIOR WITH WINDS VEERING FROM SW TO WNW AROUND 12Z. 850 MB TEMPS TO AROUND -15C BY 12Z SHOULD SUPPORT INCREASING LES POTENTIAL INTO NW UPPER MI. SNOW GROWTH PARAMETERS ARE FAVORABLE BTWN 09Z-15Z WITH THE 2K-8K FT LAYER IN THE -12C TO -17C RANGE. HOWEVER...THE PERIOD OF BEST LOW LEVEL CONV IS RELATIVELY BRIEF AND THE DEEPER MOISTURE MOVES OUT BEFORE THE COLDER AIR ARRIVES. VERY DRY AIR MOVING IN BY MIDDAY ALONG WITH A SHORTER FETCH AS WINDS VEER NW AND INVERSION HEIGHTS FALLING TO AROUND 4K FT...SHOULD DECREASE SNOWFALL RATES/COVERAGE WITH MAINLY SCT -SHSN/FLURRIES BY AFTERNOON. WRLY WINDS JUST BRUSHING THE SHORELINE E OF MUNISING WILL VEER NW IN THE AFTERNOON. AGAIN...BY THAT TIMES...SIGNIFICANT DRY ADVECTION AND LOWERING INVERSION HEIGHTS WILL LIMIT LES POTENTIAL WITH ONLY LIGHT ACCUMULATIONS. .LONG TERM... AS POINTED OUT BY HPC...ECMWF IS THE PREFERRED SOLUTION THROUGH THE EXTENDED. THE MID LEVEL LOW OVER NORTHERN ONTARIO WILL MOVE OVER NORTHERN ONTARIO WEDNESDAY NIGHT AS A WEAK SHORTWAVE WRAPPING AROUND THIS LOW SWEEPS INTO THE NORTHERN PLAINS. A SURFACE LOW ASSOCIATED WITH THIS SHORTWAVE WILL DEEPEN OVER THE CENTRAL PLAINS. THE ACCOMPANYING COLD FRONT WILL MOVE SOUTHEAST OVERNIGHT STRETCHING FROM SOUTHEAST ONTARIO THROUGH NORTHERN LOWER MICHIGAN TO THE LOW OVER THE TEXAS PANHANDLE. CONSIDERABLE AMOUNT OF LOW LEVEL MOISTURE WILL MOVE INTO THE AREA AHEAD OF THE LOW. THE STRONGEST ISENTROPIC ASCENT WILL STILL BE OVER WISCONSIN. THE MID LEVEL LOW WILL LIFT INTO SOUTHEAST HUDSON BAY DIRECTING A SHORTWAVE THROUGH THE U.P. ON THURSDAY. THE SURFACE LOW WILL MOVE INTO NORTHERN WISCONSIN. WINDS SHOULD DECREASE OVER THE FORECAST IN THE CLOSE PROXIMITY OF THE LOW. GUIDANCE SHOWING THE DEEPEST MOISTURE WILL BE TO THE SOUTH OF THE FORECAST AREA. DELTA-T`S WILL AROUND -23C. PLAN TO GO WITH A WATCH FOR MOST OF THE SOUTHERN COUNTIES AS THIS WILL BE CLOSEST TO THE DEEPEST MOISTURE FIELD AND THE AREA OF STRONGEST 850-500MB Q-VECTORS CONVERGENCE DURING THE DAY. AFTER THE SURFACE LOW SETTLE INTO LOWER MICHIGAN ON THURSDAY...THE WINDS WILL BECOME MORE NORTHERLY. THE SURFACE RIDGE WILL SWEEP INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THUS LOOKING FOR LES TO DEVELOP OVER THE WESTERN U.P. AND EAST OF MUNISING AGAIN THURSDAY NIGHT. THE MID LEVEL CLOSED LOW WILL SHIFT INTO WEST CENTRAL QUEBEC AS A WEAK SHORTWAVE RACE ACROSS THE FORECAST AREA. THE SURFACE WINDS WILL BACK WEST ON FRIDAY AS THE RIDGE DESCENDS ON THE UPPER GREAT LAKES. THE DELTA-T`S WILL BE AROUND 20C. WINDS WILL CONTINUE TO BACK TO THE WEST. THUS THE LAKE EFFECT SNOWS WILL END AS THE RIDGE MOVES THROUGH. THE LONGWAVE TROUGH WILL SLIDE INTO NEW ENGLAND FRIDAY NIGHT WHILE SURFACE HIGH MOVES INTO THE OHIO RIVER VALLEY AND THE LOWER GREAT LAKES. WINDS WILL BE LIGHT EARLY AND BECOME OUT OF THE SOUTHWEST LATE. THE WATER-850MB DELTA-T`S WILL BE AROUND 20C OVER EASTERN LAKE SUPERIOR TO AROUND 14C OVER THE WEST. STILL BOTH COOL ENOUGH TO GENERATE SOME LAKE EFFECT SNOW. HOWEVER...WITH THE LIGHT WINDS AND WINDS BACKING SOUTHWEST...THE LES WILL SHIFT OUT OF THE U.P. MEANWHILE...A COLD FRONT WILL DEVELOP OVER SOUTH CENTRAL CANADA AND SWEEP INTO NORTHERN MINNESOTA AND WESTERN ONTARIO ON SATURDAY. WEAK ISENTROPIC ASCENT AHEAD OF THE FRONTAL SYSTEM AND LOW LEVEL MOISTURE DRAWN INTO THE AREA WITH THE SOUTHWEST FLOW WILL GENERATE SOME SNOWS OVER THE AREA. SINCE THE WEST END OF THE FORECAST AREA IS STILL FAR ENOUGH AWAY FROM THE FRONT THE CHANCES WILL STILL BE SLIGHT. THE LOW AND ACCOMPANYING COLD FRONT WILL SWEEP INTO THE U.P. SATURDAY NIGHT AND INTO EASTERN ONTARIO ON SUNDAY. MEANWHILE...A TROUGH DEEPENING OVER SOUTH CENTRAL CANADA WILL MOVE OVER WESTERN ONTARIO AND THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY NIGHT AND THROUGH THE U.P. ON SUNDAY. WINDS WILL SHIFT NORTHWEST FOLLOWING THE FROPA. THE CHANCE OF SNOW WILL SPREAD ACROSS THE FORECAST AREA. COLD AIR WILL STREAM INTO THE AREA SUNDAY NIGHT AND MONDAY. A LOW LEVEL THERMAL TROUGH WILL MOVE INTO WESTERN ONTARIO AND THE 850MB TEMPERATURES DROP TO AROUND -20C OVER THE WESTERN LAKE. THIS SHOULD GENERATE LES...MAINLY OVER AREAS PRONE TO LES WITH A NORTHWEST FLOW. THE LONGWAVE TROUGH WILL REMAIN OVER THE UPPER GREAT LAKES REGION THROUGH TUESDAY...CONTINUING TO PULL COLD AIR INTO THE FORECAST AREA. A COLD POOL OF LOW LEVEL AIR WILL BE OVER WESTERN ONTARIO WITH THE THERMAL TROUGH EXTENDING INTO WESTERN LAKE SUPERIOR. 850MB TEMPERATURES WILL LOWER TO -24C OVER THE WESTERN LAKE. LES WILL CONTINUE. HOWEVER...THE VERY COLD AIR WILL BE PARTICULARLY DRY SO DO NOT EXPECT HEAVY SNOWFALL. AT THIS TIME THE MODELS ARE NOT CALLING FOR STRONG WINDS. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS SHOULD PREVAIL AT KCMX THIS AFTERNOON AS LOWER CIGS FROM THE SOUTH GET ADVECTED IN. THERE ARE MVFR CIGS IN WI AND WITH SW WINDS...THOSE SHOULD MAKE IT INTO KCMX WHERE THEY WILL REMAIN THROUGH THE PERIOD. AT KSAW...MVFR CIGS SHOULD PREVAIL THRU MOST OF THIS FCST PERIOD UNTIL LATE TONIGHT WHEN SW WINDS CREATE SOME DOWNSLOPE WHICH SHOULD HELP TO BREAK UP THE MVFR CIGS AND CONDITIONS WILL THEN GO VFR. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRES MOVING THROUGH NRN ONTARIO TO JAMES BAY WILL DRAG A COLD FRONT ACROSS LAKE SUPERIOR LATE TONIGHT AND WED MORNING. SW WINDS ARE EXPECTED TO INCREASE INTO THE 20-30 KT RANGE OVER THE W BY MIDNIGHT AND VEER NW AS THE FRONT MOVES THROUGH. THE WINDS WILL DIMINISH LATE WED INTO WED NIGHT AS A WEAK RIDGE BUILDS INTO THE REGION. LOW PRES MOVING TOWARD THE SOUTHERN GREAT LAKES THU WILL BRING AN INCREASE IN N WINDS TO 15 TO 25 KT. OTHERWISE...WINDS SHOULD REMAIN BLO 30 KT UNTIL A STRONGER LOW PRESSURE SYSTEM MOVES EASTWARD THROUGH NRN ONTARIO OR LAKE SUPERIOR LATE SATURDAY INTO SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...JLB LONG TERM...DLG AVIATION/MARINE...JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1230 AM EST TUE FEB 12 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAFS. .UPDATE (ISSUED AT 1024 PM EST)... MAIN FCST ISSUE OVERNIGHT IS TEMPS. AT 02Z...A WIDE RANGE OF TEMPS EXISTS ACROSS THE FCST AREA...RANGING FROM NEAR -10F WHERE SKIES ARE MOSTLY CLEAR (MAINLY INTERIOR SRN UPPER MI) TO AROUND 10 ABOVE WHERE SKIES ARE CLOUDY. FLURRIES/-SHSN AFFECTING PARTS OF THE NW FCST AREA AND ERN PARTS OF THE FCST AREA WILL END OVER THE NEXT FEW HRS...AND LAKE EFFECT CLOUDS WILL CLEAR OUT. SO...TEMPS WILL HAVE AN OPPORTUNITY TO NOSE DIVE LATER IN THE NIGHT. HOWEVER...MID CLOUDS ARE FAIRLY WIDESPREAD ACROSS NRN MN. THESE MAY SPREAD INTO PARTS OF THE FCST AREA OVERNIGHT...THOUGH 00Z RUC IS SLOW TO SPREAD THE CLOUDS E. ANOTHER CLOUD ISSUE IS LAKE EFFECT OFF LAKE MICHIGAN. WHILE SFC WINDS WILL NOT BECOME SE...AT 950MB AND ABOVE...WIND DOES BECOME SERLY DURING THE NIGHT. THIS SHOULD RESULT IN CLOUDS DEVELOPING INTO CNTRL UPPER MI. SO...CLOUD FCST IS NOT A SIMPLE MATTER WHICH MAKES TEMP FCST EXTREMELY DIFFICULT. HAVE LOWERED MINS TO -15 TO -20F ALONG THE WI BORDER FROM E OF KIWD TOWARD KIMT GIVEN CURRENT TEMPS AND POTENTIAL FOR THAT AREA TO SEE LEAST CLOUD COVER FOR LONGEST DURATION DURING THE NIGHT. ALSO LOWERED TEMPS SUBSTANTIALLY FROM MENOMINEE COUNTY TO SRN SCHOOLCRAFT. BEFORE CLOUDS INCREASE LATER IN THE NIGHT...THERE SHOULD BE AN OPPORTUNITY FOR TEMPS TO CRASH. LOWERED TEMPS TOWARD -10F IN THOSE AREAS. AS FOR PCPN...FORCING ASSOCIATED WITH SHORTWAVE MOVING E ACROSS THE CNTRL PLAINS WILL REMAIN WELL TO THE S THRU THE NIGHT. IN ADDITION...EVENING SOUNDINGS INDICATE A FAIR AMOUNT OF DRY AIR TO OVERCOME. HAVE THUS TRIMMED POPS OVER THE SRN FCST AREA OVERNIGHT. ONLY RETAINED LOW POPS NEAR LAKE MICHIGAN WHERE SOME LAKE EFFECT FLURRIES/-SHSN MAY DEVELOP LATE...MAINLY S OF KESC. && .PREV DISCUSSION (ISSUED AT 400 PM EST)... SHORT TERM (TNGT AND TUE)... WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER EASTERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA. A RIDGE IS OVER THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. A SHORTWAVE IS DIGGING OVER THE NORTHERN PLAINS AS IT SLIDES DOWN THE LEE OF THE WEST COAST RIDGE. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES REGION...WHILE A LOW IS DEEPENING OVER TEXAS. A WARM FRONT IS DEVELOPING OVER THE NORTHERN HIGH PLAINS. MOST OF THE U.P. STATIONS ARE REPORTING TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO. THE EXCEPTIONS ARE AREAS ALONG THE LAKE SUPERIOR SHORE WHERE TEMPERATURES REACH INTO THE TEENS. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH TUESDAY. WINDS WILL REMAIN FROM THE NORTH TONIGHT. TEMPERATURES DELTA-T`S CONTINUE TO BE COOL ENOUGH TO PRODUCE LAKE EFFECT SNOWS OVER AREA PRONE TO LES WITH A NORTH FLOW. THE SHORTWAVE OVER THE NORTHERN PLAINS WILL DEEPEN INTO A TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT AND SHIFT INTO THE UPPER MICHIGAN ON TUESDAY. GFS SHOWING WARM AIR ADVECTION AND A SLIGHT INCREASE IN SURFACE DEW POINT OVER THE AREA AS LOW LEVEL MOISTURE OUT OF THE CENTRAL PLAINS PUSH TOWARDS THE UPPER GREAT LAKES. 850MB TEMPERATURES WILL STILL REMAIN AROUND -16C STILL COOL ENOUGH OVER THE LAKES TO PRODUCE SOME LAKE EFFECT SNOW OVER THE SOUTHERN U.P. WHERE THERE WILL BE A SOUTHERLY FLOW. LONG TERM (TUE NGT THRU MON)... ON TUE NGT/WED...MOST MODELS HAVE CONTINUED TO TREND WEAKER WITH SHRTWV FCST TO SWING THRU ONTARIO AND ASSOCIATED COLD FROPA INTO THE UPR GRT LKS LATE TUE NGT AND WED DESPITE UPR PATTERN FEATURING HI AMPLITUDE RDG OVER WRN CAN THAT WOULD SUPPORT A MORE STRONGLY DIGGING SYS. GIVEN FVRBL UPR PATTERN...WL BLEND THE GFS WITH THE STRONGER 12Z UKMET FOR THIS SYS. THAT SCENARIO SUGS ASSOCIATED COLD FNT WL APRCH THE WRN ZNS AFT MIDNGT TUE NGT...SO MAINTAINED GOING CHC POPS IN THAT AREA WHERE UPSLOPE FLOW WL TEND TO OFFSET DRYNESS. THEN SOME LGT LES NEAR LK SUP ON WED WITH COLD AIR INTRUSION BEHIND COLD FROPA (H85 TEMPS FCST ON WED RANGES FM -20C TO -24C PER THE UKMET TO -16C TO -20C ON THE GFS). RELATIVELY SHALLOW...DRY NATURE OF COLD AIR INTRUSION AND GENERAL ACYC FLOW IN THE WAKE OF COLD FNT SHOULD LIMIT LES AMTS. EXACT FCST FOR WED NGT AND THU DEPENDS ON COMPLEX INTERACTION BTWN POLAR AND ARCTIC BRANCH DISTURBANCES OVER THE UPR MS VALLEY AND ASSOCIATED SFC LO DVLPMNT/FGEN ON ITS NRN FLANK. PER NCEP GUIDANCE...TRENDED TOWARD THE GFS HANDLING OF THIS INTERACTION BTWN ARCTIC AIR SURGING S FM CAN AND LO PRES DVLPG IN ADVANCE OF POLAR BRANCH SHRTWV. OPTED TO BUMP POPS UP TO HI LIKELY OVER THE SRN TIER LATE WED NGT/THU CLOSER TO LO PRES TRACK TO THE S. SHARP H85-7 FGEN AND UPR DVGC IN THE RRQ OF H3 JET MAX JUST S OF JAMES BAY JUSTIFIES POPS TOWARD THE HI END OF ENSEMBLE GUIDANCE. ELY FLOW OVER NRN LK MI WITH H85 TEMPS ARND -12C WL SUPPORT SOME LK ENHANCEMENT OVER THE SCNTRL WITH HIER QPF THERE. WITH SHARP FGEN TENDING TO ENHANCE LLVL CAD...TENDED TOWARD THE LOWER END OF MOS GUIDANCE FOR TEMPS. TIMING DIFFERENCES AS TO THE DEPARTURE SPEED OF SFC LO ON THU NGT AND TREND TOWARD TRANSITION TO PURE LES. SINCE 12Z GFS HAS TRENDED TOWARD THE 00Z ECMWF WITH FASTER EXIT OF THE LO...TENDED TO FOLLOW THAT TREND WITH FASTER END OF PCPN OVER THE S/TRANSITION TO LES NEAR LK SUP. THEN PERSISTENT LES ON FRI NEAR LK SUP WITH INFLUX OF VERY COLD AIR (GFS SHOWS H85 TEMPS SINKING TO ARND -25C). APRCH OF SHRTWV RDGING/SFC HI ON FRI NGT/SAT WL DIMINISH THESE SHSN. HEDGED TOWARD THE LOWER END OF MOS GUIDANCE FOR SAT MRNG LO TEMPS WITH ARRIVAL OF RDG AXIS/LIGHTER WINDS. NEXT CLIPPER LO DUE TO APRCH LATE SAT AND BRING CHC POPS...HIEST TO THE N...AS CLIPPER TRACKS ACRS LK SUP/ONTARIO ON SUN. TEMPS WL REBOUND TO NEAR NORMAL WITH FAIRLY STRG SW FLOW IN ADVANCE OF THIS SYS...BUT ARRIVAL OF REINFORCING SHRTWV/COLD FNT ON LATE SUN/MON WL TREND TEMPS DOWN AGAIN AND RESTART LES. COORDINATED WITH NCEP/APX/LOT/GRB/DLH. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... VFR CONDITIONS SHOULD PREVAIL AT KCMX THRU THIS FCST PERIOD SINCE LOW-LEVEL WINDS WILL NOT HAVE AN OVER WATER COMPONENT. AT KSAW... MVFR CIGS SHOULD PREVAIL THRU THIS FCST PERIOD. LAKE EFFECT CLOUDS INITIALLY OFF LAKE SUPERIOR MAY SCATTER OUT FOR A TIME AT KSAW DURING THE NIGHT BEFORE LAKE EFFECT CLOUDS OFF LAKE MICHIGAN FORM IN DEVELOPING SERLY FLOW. MAY SEE SOME FLURRIES LATE MORNING THRU THE AFTN AS WELL. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUESDAY NIGHT. THE GFS TAKES THE FRONT. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE UPPER LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. HEAVY FREEZING SPRAY IS LIKELY OVER AT PORTIONS OF THE LK ON WED NGT THRU SAT AS COLD AIR RETAINS ITS LOCK ON THE UPR GRT LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SHORT TERM...DLG LONG TERM...KC AVIATION...ROLFSON MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1152 PM EST MON FEB 11 2008 .AVIATION... AN EXTREMELY DRY LOW LEVEL AIRMASS WILL KEEP CONDITIONS IN VFR THROUGH AT LEAST AT LEAST 12Z...BEFORE DEEPER SATURATION BEGINS TO OCCUR FROM SOUTH TO NORTH THROUGH MID/LATE MORNING. LATEST UPSTREAM OBSERVATIONS AND MODEL GUIDANCE CONTINUE TO SUPPORT A SLOWER TIMING FOR THE ONSET OF MFVR LIGHT SNOW...WITH THESE CONDITIONS PROJECTED TO DEVELOP AFTER 14Z AT DTW/DET AND NOT UNTIL CLOSER TO 18Z AT MBS. A PERIOD OF HIGHER INTENSITY SNOWFALL STILL LOOKS ON TRACK THE AFTERNOON/EVENING HOURS...WITH CONDITIONS FLUCTUATING BETWEEN IFR/LIFR DURING THIS TIME. LIGHT WINDS OVERNIGHT WILL INCREASE TO AROUND 10 KNOTS OUT OF THE EAST ON TUESDAY. && .PREV DISCUSSION...ISSUED 1037 PM EST MON FEB 11 2008 UPDATE... LATEST RADAR...ALONG WITH SUPPORTIVE 00Z RUC/NAM GUIDANCE...INDICATING THE NARROW BAND OF LGT/MDT SNOW ASSOCIATED WITH AN AREA OF MID- LEVEL FGEN FORCING WILL REMAIN JUST SOUTH OF THE MICHIGAN BORDER AS IT CONTINUES TO WEAKEN OVERNIGHT. BESIDES THIS FEATURE...OVERALL FORCING LOOKS MEAGER PRIOR TO 12Z...GIVEN LIMITED ISENTROPIC LIFT/LARGE SCALE ACCENT. THUS...WILL TRIM POPS BACK FOR TONIGHT...HOLDING ON TO JUST A LOW CHANCE FOR RIGHT AROUND DAYBREAK ACROSS THE SOUTHERN TWO TIER OF COUNTIES. ACCUMULATIONS LOOK TO BE LITTLE IF ANY FOR THE MORNING COMMUTE. IN FACT...00Z NAM JUST ROLLING IN SUGGESTS THE DEEPER MOISTURE WILL HOLD OFF UNTIL TOMORROW AFTERNOON/EVENING. REGIONAL OBSERVATIONS INDICATING THE POTENTIAL FOR SOME GOOD RADIATIONAL COOLING...GIVEN A WEAK GRADIENT AND LACK OF CLOUD COVER (ESPECIALLY NORTHERN HALF). SEEING A WIDE RANGE IN TEMPERATURES AT THE MOMENT...WITH TEMPERATURES IN OAKLAND COUNTY ALONE RANGING FROM -3F IN WHITE LAKE TO 12F IN TROY. GIVEN THE DRYNESS OF THIS AIRMASS (DEWPOINTS 0 TO -5F) THE POTENTIAL EXISTS FOR QUITE A FEW LOCATIONS TO BOTTOM OUT BELOW 0F. THUS...ADJUST LOWS DOWN SLIGHTLY SLIGHTLY...ESPECIALLY FROM M-59 NORTHWARD. PREV DISCUSSION...ISSUED 401 PM EST MON FEB 11 2008 SHORT TERM... THIS AFTERNOON AND TONIGHT LOW-LEVEL CONVERGENCE BETWEEN AN EAST TO WEST ORIENTATED SURFACE TROUGH OVER NORTHERN LOWER MICHIGAN...AND STRONG SURFACE HIGH PRESSURE OVER THE SOUTHERN GREAT LAKES...HAS BROUGHT SOME CLOUDINESS/FLURRIES INTO THE EXTREME NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. DESPITE ITS SOUTHWARD PROGRESSION SEEN ON SATELLITE IMAGERY EARLIER TODAY...THESE CLOUDS SHOULD MAKE LITTLE ADDITIONAL PROGRESSION INTO THE TRI-CITIES AND THUMB THE REST OF THE AFTERNOON AS SURFACE HIGH DRIFTS NORTHWARD THROUGH THE LATE AFTERNOON AND EVENING...AND THE EAST/WEST TROUGH IS FORCED TO RETREAT BACK NORTHWARD. MAY SEE SOME FLURRIES OR LIGHT SNOW SHOWERS OVER THE FAR NORTHERN PORTIONS OF MIDLAND...BAY...AND HURON COUNTIES...AS WELL AS SAGINAW BAY...INTO THE EARLY EVENING BEFORE ACTIVITY AND LOW-LEVEL CLOUDS ARE PUSHED BACK NORTH. OTHERWISE...SURFACE HIGH PRESSURE WILL BRING QUIET WEATHER TO THE REST OF THE AREA DURING THE LATE AFTERNOON AND FIRST HALF OF THE NIGHT. DIFFUSE UPPER TROUGH CURRENTLY CROSSING THE NORTHERN ROCKIES WILL CONSOLIDATE AND AMPLIFY AS IT MOVES INTO THE CENTRAL PLAINS OVERNIGHT. SURFACE REFLECTION WILL TRACK FROM THE SOUTHERN PLAINS INTO THE TENNESSEE VALLEY BY DAYBREAK...ALLOWING THE NORTHERN FRINGE OF THE 925-850MB BAROCLINIC ZONE TO LIFT INTO FAR SOUTHERN MICHIGAN DURING THE EARLY MORNING HOURS. GFS/NAM CONTINUE TO INDICATE SOME FAIRLY LIGHT ISENTROPIC LIFT OCCURRING OVER THE SOUTHERN HALF OF THE FORECAST AREA AFTER 06Z. MODEL TRENDS HAVE BEEN SLIGHTLY SLOWER WITH THE ARRIVAL OF THE BAROCLINIC ZONE AND QPF...AND WILL TWEAK FORECAST ACCORDINGLY. LIKELY POPS WERE KEPT FROM DETROIT SOUTHWARD...WITH UP TO ABOUT A HALF INCH OF SNOW ACCUMULATION. ELSEWHERE...JUST CHANCE POPS WITH A DUSTING OF SNOW EXPECTED AT BEST THROUGH 700 AM. CLOUDS WILL INCREASE OVERNIGHT IN ADVANCE OF THIS NEXT WINTER STORM. THIS WILL HELP KEEP TEMPERATURES IN THE SINGLE DIGITS FOR MOST AREAS. WIND CHILLS WILL NOT BE AN ISSUE AS WINDS BECOME LIGHT UNDER THE SURFACE HIGH. WILL CONTINUE TO FORECAST AT THE LOWER END OF MOS GUIDANCE IN THE SOUTH...AND A FEW DEGREES BELOW GUIDANCE FROM I-69 NORTHWARD AS MOS NUMBERS THERE HAVE BEEN TOO WARM RECENTLY. LONG TERM...TUESDAY THROUGH NEXT MONDAY SNOW WILL BE UNDERWAY NEAR THE OHIO BORDER AT SUNRISE TUESDAY, WILL SPREAD NORTHWARD DURING THE MORNING HOURS, AND REACH THE TRI CITIES AND NORTHERN THUMB BY AFTERNOON. THE SNOW WILL THEN DIMINISH IN A SIMILAR FASHION, FROM SOUTH TO NORTH, DURING THE LATE AFTERNOON IN THE SOUTH AND DURING TUESDAY EVENING IN THE NORTH WITH SOME LAKE EFFECT LINGERING IN THE THUMB. TOTAL ACCUMULATION COULD EXCEED ADVISORY THRESHOLD OF 4 INCHES IN 18 TO 24 HOURS, BUT WE WILL HOLD OFF ON A HEADLINE WITH THIS FORECAST ISSUANCE AS ANY SIGNIFICANT SNOW IS NOT EXPECTED UNTIL AFTER THE PEAK TUESDAY MORNING DRIVE TIME. THE SYSTEM IN QUESTION IS TAKING SHAPE IN THE CENTRAL PLAINS THIS AFTERNOON WITH A STRONGLY ELONGATED AREA OF SNOW EXTENDING EASTWARD ALONG THE 850 TO 700 MB THETA-E GRADIENT. THIS PATTERN WILL BE ADVECTED NORTHWARD INTO OUR OHIO BORDER COUNTIES BY SUNRISE TUESDAY MORNING AND WILL PROCEED NORTHWARD AS THETA-E/WARM ADVECTION UNFOLDS AS THE PRIMARY MODE OF FORCING DURING THE MORNING HOURS. AFTER THAT, THERE IS GOOD MODEL AGREEMENT SHOWING THETA-E ADVECTION COMBINING WITH DYNAMIC FORCING DURING THE AFTERNOON IN TERMS OF DCVA WITH THE UPPER WAVE. MORE IMPORTANT IS THE MOISTURE, STABILITY, AND TEMPERATURE PROFILES REVEALED IN MODEL SOUNDINGS AND CROSS SECTIONS WHICH SUGGEST AN IMPRESSIVE BURST OF SNOW DURING THE 15Z TO 00Z TIME PERIOD. THIS IS WHERE THE BEST LIFT COMBINES WITH THE LOWEST MID LEVEL STABILITY, AND EVEN SHALLOW LAYERS OF CONVECTION, ABOVE THE FRONTAL ZONE. FORECAST SOUNDINGS ALSO SHOW A DEEP LAYER OF ISOTHERMAL TEMPERATURES IN THE -10 TO -15C RANGE WHICH SHOULD BE FAVORABLE FOR SNOW CRYSTAL GROWTH. AT THE SAME TIME, THIS COULD BE A LIMITING FACTOR IF TEMPERATURES GET TOO CLOSE TO -10C OR EVEN BECOME WARMER THAN -10C AND/OR ARE ONLY SATURATED AT WARMER TEMPERATURES BELOW THAT LEVEL. THERE IS POTENTIAL FOR THIS TO OCCUR FROM ABOUT DETROIT SOUTH WHERE MID LEVEL DRY AIR IS SHOWN TO HAVE A CHANCE OF MOVING INTO THE AREA BY LATE IN THE DAY. THE TRAILING DEFORMATION ON THE NORTH AND WEST FLANK OF THE UPPER WAVE WILL GIVE A BOOST TO ANY LAKE EFFECT IN THE THUMB TUESDAY NIGHT. A SHORT PERIOD OF NORTHERLY FLOW WITH INVERSION HEIGHT NEAR 7 KFT AND LAKE TO 850 MB DELTA-T AROUND 18C WILL SET UP POTENTIAL FOR AN EXTRA COUPLE OF INCHES OF SNOW IN THAT AREA BEFORE THE WINDS TURN TO THE NW BY WEDNESDAY MORNING. HIGH PRESSURE WILL THEN MOVE VERY QUICKLY THROUGH SE MICHIGAN ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM TAKES SHAPE OVER CENTRAL SECTIONS OF THE COUNTRY. AGREEMENT ON THIS PATTERN DURING THURSDAY AND FRIDAY IS BETTER TODAY AMONG THE 12Z MODEL RUNS. PAST DIFFERENCES WERE RELATED TO THE DEPTH OF THE NORTHERN STREAM TROUGH AXIS OVER CENTRAL CANADA AND THE NORTHERN PLAINS. IT SEEMS THAT THE 12Z RUNS HAVE COME INTO AGREEMENT ON A STRONGER NORTHERN TROUGH AND FASTER SURFACE LOW IN THE GREAT LAKES ON THURSDAY FOLLOWED BY THE ASSOCIATED COLD FRONT THURSDAY NIGHT AND FRIDAY. OUR NEXT BEST CHANCE FOR ACCUMULATING SNOW WILL BE WITH THE COLD FRONT PASSAGE AROUND 12Z FRIDAY MORNING. ANY REMAINING TIMING DIFFERENCES IN MODEL SOLUTIONS REGARDING THE FRIDAY SYSTEM ARE WORKED OUT BY SATURDAY. EXPECTATIONS FOR THE FIRST HALF OF THE WEEKEND REMAIN DRY WITH BELOW NORMAL TEMPERATURES, ONLY NOT AS FRIGID AS RECENT DAYS. THE GLOBAL MODELS ALL INDICATE SOME FASHION OF SURFACE HIGH PRESSURE OVER THE AREA ON SATURDAY TO FOSTER THE DRY CONDITIONS. HIGHS IN THE MID TO UPPER 20S LOOK OK FROM THE GUIDANCE NUMBERS. A CHANCE OF SNOW THEN RETURNS TO THE FORECAST FOR SUNDAY AND MONDAY AS A DEEPENING UPPER TROUGH MOVES INTO THE GREAT LAKES FROM CENTRAL CANADA. MARINE... HIGH PRESSURE WILL CONTINUE TO BE DOMINANT OVER THE GREAT LAKES FOR BENIGN WEATHER CONDITIONS THROUGH MOST OF THE NIGHT. A LOW PRESSURE SYSTEM MOVING INTO THE OHIO VALLEY WILL BRING SNOW TO LOWER MICHIGAN AND THE CENTRAL GREAT LAKES ON TUESDAY. HEADLINES (SMALL CRAFT OR BRISK WIND ADVISORIES) FOR WINDS AND WAVES WILL NOT BE NEEDED IN ASSOCIATION WITH THE PASSAGE OF THIS SYSTEM...AS WINDS WILL REMAIN BELOW THE THRESHOLDS. THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE WESTERN GREAT LAKES ON THURSDAY...BRINGING AN INCREASE TO SOUTHERLY WINDS. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL SWEEP DOWN THROUGH THE GREAT LAKES THURSDAY NIGHT AND FRIDAY AS THE LOW MOVES ACROSS LAKE HURON AND INTO ONTARIO. THIS WILL CAUSE WINDS TO VEER TO THE NORTHWEST...BUT SPEEDS ARE EXPECTED TO REMAIN UNDER 20 KNOTS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MR UPDATE.......MR SHORT TERM...HLO LONG TERM....BT MARINE.......HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1037 PM EST MON FEB 11 2008 .UPDATE... LATEST RADAR...ALONG WITH SUPPORTIVE 00Z RUC/NAM GUIDANCE...INDICATING THE NARROW BAND OF LGT/MDT SNOW ASSOCIATED WITH AN AREA OF MID- LEVEL FGEN FORCING WILL REMAIN JUST SOUTH OF THE MICHIGAN BORDER AS IT CONTINUES TO WEAKEN OVERNIGHT. BESIDES THIS FEATURE...OVERALL FORCING LOOKS MEAGER PRIOR TO 12Z...GIVEN LIMITED ISENTROPIC LIFT/LARGE SCALE ACCENT. THUS...WILL TRIM POPS BACK FOR TONIGHT...HOLDING ON TO JUST A LOW CHANCE FOR RIGHT AROUND DAYBREAK ACROSS THE SOUTHERN TWO TIER OF COUNTIES. ACCUMULATIONS LOOK TO BE LITTLE IF ANY FOR THE MORNING COMMUTE. IN FACT...00Z NAM JUST ROLLING IN SUGGESTS THE DEEPER MOISTURE WILL HOLD OFF UNTIL TOMORROW AFTERNOON/EVENING. REGIONAL OBSERVATIONS INDICATING THE POTENTIAL FOR SOME GOOD RADIATIONAL COOLING...GIVEN A WEAK GRADIENT AND LACK OF CLOUD COVER (ESPECIALLY NORTHERN HALF). SEEING A WIDE RANGE IN TEMPERATURES AT THE MOMENT...WITH TEMPERATURES IN OAKLAND COUNTY ALONE RANGING FROM -3F IN WHITE LAKE TO 12F IN TROY. GIVEN THE DRYNESS OF THIS AIRMASS (DEWPOINTS 0 TO -5F) THE POTENTIAL EXISTS FOR QUITE A FEW LOCATIONS TO BOTTOM OUT BELOW 0F. THUS...ADJUST LOWS DOWN SLIGHTLY SLIGHTLY...ESPECIALLY FROM M-59 NORTHWARD. && .PREV DISCUSSION...ISSUED 618 PM EST MON FEB 11 2008 AVIATION... VFR CONDITIONS WILL PERSIST THROUGH TONIGHT...WITH HIGHER CLOUD COVER ABOVE 10KFT CONTINUING TO THICKEN. HIGH PRESSURE OVER THE AREA WILL SLIDE EAST TONIGHT WHILE LOW PRESSURE LIFTS TOWARD THE OHIO VALLEY ON TUESDAY. THIS WILL BRING A WIND SHIFT TO THE EAST OVERNIGHT...AND ALLOW LIGHT SNOW TO EVENTUALLY OVERSPREAD SOUTHEAST LOWER MICHIGAN FROM SOUTH TO NORTH ON TUESDAY. MODELS CONTINUE TO TREND SLOWER WITH THE INITIAL ONSET OF SNOW...HOLDING OFF MVFR CONDITIONS UNTIL THE 12-16Z TIMEFRAME. A BURST OF HEAVIER SNOW LOOKS TO OCCUR BETWEEN 18-00Z...BRINGING CONDITIONS DOWN INTO PREVAILING IFR...WITH OCCASIONAL PERIODS OF LIFR ESPECIALLY AT DTW/DET/FNT. PREV DISCUSSION...ISSUED 401 PM EST MON FEB 11 2008 SHORT TERM... THIS AFTERNOON AND TONIGHT LOW-LEVEL CONVERGENCE BETWEEN AN EAST TO WEST ORIENTATED SURFACE TROUGH OVER NORTHERN LOWER MICHIGAN...AND STRONG SURFACE HIGH PRESSURE OVER THE SOUTHERN GREAT LAKES...HAS BROUGHT SOME CLOUDINESS/FLURRIES INTO THE EXTREME NORTHERN PORTIONS OF THE FORECAST AREA THIS AFTERNOON. DESPITE ITS SOUTHWARD PROGRESSION SEEN ON SATELLITE IMAGERY EARLIER TODAY...THESE CLOUDS SHOULD MAKE LITTLE ADDITIONAL PROGRESSION INTO THE TRI-CITIES AND THUMB THE REST OF THE AFTERNOON AS SURFACE HIGH DRIFTS NORTHWARD THROUGH THE LATE AFTERNOON AND EVENING...AND THE EAST/WEST TROUGH IS FORCED TO RETREAT BACK NORTHWARD. MAY SEE SOME FLURRIES OR LIGHT SNOW SHOWERS OVER THE FAR NORTHERN PORTIONS OF MIDLAND...BAY...AND HURON COUNTIES...AS WELL AS SAGINAW BAY...INTO THE EARLY EVENING BEFORE ACTIVITY AND LOW-LEVEL CLOUDS ARE PUSHED BACK NORTH. OTHERWISE...SURFACE HIGH PRESSURE WILL BRING QUIET WEATHER TO THE REST OF THE AREA DURING THE LATE AFTERNOON AND FIRST HALF OF THE NIGHT. DIFFUSE UPPER TROUGH CURRENTLY CROSSING THE NORTHERN ROCKIES WILL CONSOLIDATE AND AMPLIFY AS IT MOVES INTO THE CENTRAL PLAINS OVERNIGHT. SURFACE REFLECTION WILL TRACK FROM THE SOUTHERN PLAINS INTO THE TENNESSEE VALLEY BY DAYBREAK...ALLOWING THE NORTHERN FRINGE OF THE 925-850MB BAROCLINIC ZONE TO LIFT INTO FAR SOUTHERN MICHIGAN DURING THE EARLY MORNING HOURS. GFS/NAM CONTINUE TO INDICATE SOME FAIRLY LIGHT ISENTROPIC LIFT OCCURRING OVER THE SOUTHERN HALF OF THE FORECAST AREA AFTER 06Z. MODEL TRENDS HAVE BEEN SLIGHTLY SLOWER WITH THE ARRIVAL OF THE BAROCLINIC ZONE AND QPF...AND WILL TWEAK FORECAST ACCORDINGLY. LIKELY POPS WERE KEPT FROM DETROIT SOUTHWARD...WITH UP TO ABOUT A HALF INCH OF SNOW ACCUMULATION. ELSEWHERE...JUST CHANCE POPS WITH A DUSTING OF SNOW EXPECTED AT BEST THROUGH 700 AM. CLOUDS WILL INCREASE OVERNIGHT IN ADVANCE OF THIS NEXT WINTER STORM. THIS WILL HELP KEEP TEMPERATURES IN THE SINGLE DIGITS FOR MOST AREAS. WIND CHILLS WILL NOT BE AN ISSUE AS WINDS BECOME LIGHT UNDER THE SURFACE HIGH. WILL CONTINUE TO FORECAST AT THE LOWER END OF MOS GUIDANCE IN THE SOUTH...AND A FEW DEGREES BELOW GUIDANCE FROM I-69 NORTHWARD AS MOS NUMBERS THERE HAVE BEEN TOO WARM RECENTLY. LONG TERM...TUESDAY THROUGH NEXT MONDAY SNOW WILL BE UNDERWAY NEAR THE OHIO BORDER AT SUNRISE TUESDAY, WILL SPREAD NORTHWARD DURING THE MORNING HOURS, AND REACH THE TRI CITIES AND NORTHERN THUMB BY AFTERNOON. THE SNOW WILL THEN DIMINISH IN A SIMILAR FASHION, FROM SOUTH TO NORTH, DURING THE LATE AFTERNOON IN THE SOUTH AND DURING TUESDAY EVENING IN THE NORTH WITH SOME LAKE EFFECT LINGERING IN THE THUMB. TOTAL ACCUMULATION COULD EXCEED ADVISORY THRESHOLD OF 4 INCHES IN 18 TO 24 HOURS, BUT WE WILL HOLD OFF ON A HEADLINE WITH THIS FORECAST ISSUANCE AS ANY SIGNIFICANT SNOW IS NOT EXPECTED UNTIL AFTER THE PEAK TUESDAY MORNING DRIVE TIME. THE SYSTEM IN QUESTION IS TAKING SHAPE IN THE CENTRAL PLAINS THIS AFTERNOON WITH A STRONGLY ELONGATED AREA OF SNOW EXTENDING EASTWARD ALONG THE 850 TO 700 MB THETA-E GRADIENT. THIS PATTERN WILL BE ADVECTED NORTHWARD INTO OUR OHIO BORDER COUNTIES BY SUNRISE TUESDAY MORNING AND WILL PROCEED NORTHWARD AS THETA-E/WARM ADVECTION UNFOLDS AS THE PRIMARY MODE OF FORCING DURING THE MORNING HOURS. AFTER THAT, THERE IS GOOD MODEL AGREEMENT SHOWING THETA-E ADVECTION COMBINING WITH DYNAMIC FORCING DURING THE AFTERNOON IN TERMS OF DCVA WITH THE UPPER WAVE. MORE IMPORTANT IS THE MOISTURE, STABILITY, AND TEMPERATURE PROFILES REVEALED IN MODEL SOUNDINGS AND CROSS SECTIONS WHICH SUGGEST AN IMPRESSIVE BURST OF SNOW DURING THE 15Z TO 00Z TIME PERIOD. THIS IS WHERE THE BEST LIFT COMBINES WITH THE LOWEST MID LEVEL STABILITY, AND EVEN SHALLOW LAYERS OF CONVECTION, ABOVE THE FRONTAL ZONE. FORECAST SOUNDINGS ALSO SHOW A DEEP LAYER OF ISOTHERMAL TEMPERATURES IN THE -10 TO -15C RANGE WHICH SHOULD BE FAVORABLE FOR SNOW CRYSTAL GROWTH. AT THE SAME TIME, THIS COULD BE A LIMITING FACTOR IF TEMPERATURES GET TOO CLOSE TO -10C OR EVEN BECOME WARMER THAN -10C AND/OR ARE ONLY SATURATED AT WARMER TEMPERATURES BELOW THAT LEVEL. THERE IS POTENTIAL FOR THIS TO OCCUR FROM ABOUT DETROIT SOUTH WHERE MID LEVEL DRY AIR IS SHOWN TO HAVE A CHANCE OF MOVING INTO THE AREA BY LATE IN THE DAY. THE TRAILING DEFORMATION ON THE NORTH AND WEST FLANK OF THE UPPER WAVE WILL GIVE A BOOST TO ANY LAKE EFFECT IN THE THUMB TUESDAY NIGHT. A SHORT PERIOD OF NORTHERLY FLOW WITH INVERSION HEIGHT NEAR 7 KFT AND LAKE TO 850 MB DELTA-T AROUND 18C WILL SET UP POTENTIAL FOR AN EXTRA COUPLE OF INCHES OF SNOW IN THAT AREA BEFORE THE WINDS TURN TO THE NW BY WEDNESDAY MORNING. HIGH PRESSURE WILL THEN MOVE VERY QUICKLY THROUGH SE MICHIGAN ON WEDNESDAY AS THE NEXT LOW PRESSURE SYSTEM TAKES SHAPE OVER CENTRAL SECTIONS OF THE COUNTRY. AGREEMENT ON THIS PATTERN DURING THURSDAY AND FRIDAY IS BETTER TODAY AMONG THE 12Z MODEL RUNS. PAST DIFFERENCES WERE RELATED TO THE DEPTH OF THE NORTHERN STREAM TROUGH AXIS OVER CENTRAL CANADA AND THE NORTHERN PLAINS. IT SEEMS THAT THE 12Z RUNS HAVE COME INTO AGREEMENT ON A STRONGER NORTHERN TROUGH AND FASTER SURFACE LOW IN THE GREAT LAKES ON THURSDAY FOLLOWED BY THE ASSOCIATED COLD FRONT THURSDAY NIGHT AND FRIDAY. OUR NEXT BEST CHANCE FOR ACCUMULATING SNOW WILL BE WITH THE COLD FRONT PASSAGE AROUND 12Z FRIDAY MORNING. ANY REMAINING TIMING DIFFERENCES IN MODEL SOLUTIONS REGARDING THE FRIDAY SYSTEM ARE WORKED OUT BY SATURDAY. EXPECTATIONS FOR THE FIRST HALF OF THE WEEKEND REMAIN DRY WITH BELOW NORMAL TEMPERATURES, ONLY NOT AS FRIGID AS RECENT DAYS. THE GLOBAL MODELS ALL INDICATE SOME FASHION OF SURFACE HIGH PRESSURE OVER THE AREA ON SATURDAY TO FOSTER THE DRY CONDITIONS. HIGHS IN THE MID TO UPPER 20S LOOK OK FROM THE GUIDANCE NUMBERS. A CHANCE OF SNOW THEN RETURNS TO THE FORECAST FOR SUNDAY AND MONDAY AS A DEEPENING UPPER TROUGH MOVES INTO THE GREAT LAKES FROM CENTRAL CANADA. MARINE... HIGH PRESSURE WILL CONTINUE TO BE DOMINANT OVER THE GREAT LAKES FOR BENIGN WEATHER CONDITIONS THROUGH MOST OF THE NIGHT. A LOW PRESSURE SYSTEM MOVING INTO THE OHIO VALLEY WILL BRING SNOW TO LOWER MICHIGAN AND THE CENTRAL GREAT LAKES ON TUESDAY. HEADLINES (SMALL CRAFT OR BRISK WIND ADVISORIES) FOR WINDS AND WAVES WILL NOT BE NEEDED IN ASSOCIATION WITH THE PASSAGE OF THIS SYSTEM...AS WINDS WILL REMAIN BELOW THE THRESHOLDS. THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE WESTERN GREAT LAKES ON THURSDAY...BRINGING AN INCREASE TO SOUTHERLY WINDS. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL SWEEP DOWN THROUGH THE GREAT LAKES THURSDAY NIGHT AND FRIDAY AS THE LOW MOVES ACROSS LAKE HURON AND INTO ONTARIO. THIS WILL CAUSE WINDS TO VEER TO THE NORTHWEST...BUT SPEEDS ARE EXPECTED TO REMAIN UNDER 20 KNOTS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......MR AVIATION.....MR SHORT TERM...HLO LONG TERM....BT MARINE.......HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1024 PM EST MON FEB 11 2008 .UPDATE... MAIN FCST ISSUE OVERNIGHT IS TEMPS. AT 02Z...A WIDE RANGE OF TEMPS EXISTS ACROSS THE FCST AREA...RANGING FROM NEAR -10F WHERE SKIES ARE MOSTLY CLEAR (MAINLY INTERIOR SRN UPPER MI) TO AROUND 10 ABOVE WHERE SKIES ARE CLOUDY. FLURRIES/-SHSN AFFECTING PARTS OF THE NW FCST AREA AND ERN PARTS OF THE FCST AREA WILL END OVER THE NEXT FEW HRS...AND LAKE EFFECT CLOUDS WILL CLEAR OUT. SO...TEMPS WILL HAVE AN OPPORTUNITY TO NOSE DIVE LATER IN THE NIGHT. HOWEVER...MID CLOUDS ARE FAIRLY WIDESPREAD ACROSS NRN MN. THESE MAY SPREAD INTO PARTS OF THE FCST AREA OVERNIGHT...THOUGH 00Z RUC IS SLOW TO SPREAD THE CLOUDS E. ANOTHER CLOUD ISSUE IS LAKE EFFECT OFF LAKE MICHIGAN. WHILE SFC WINDS WILL NOT BECOME SE...AT 950MB AND ABOVE...WIND DOES BECOME SERLY DURING THE NIGHT. THIS SHOULD RESULT IN CLOUDS DEVELOPING INTO CNTRL UPPER MI. SO...CLOUD FCST IS NOT A SIMPLE MATTER WHICH MAKES TEMP FCST EXTREMELY DIFFICULT. HAVE LOWERED MINS TO -15 TO -20F ALONG THE WI BORDER FROM E OF KIWD TOWARD KIMT GIVEN CURRENT TEMPS AND POTENTIAL FOR THAT AREA TO SEE LEAST CLOUD COVER FOR LONGEST DURATION DURING THE NIGHT. ALSO LOWERED TEMPS SUBSTANTIALLY FROM MENOMINEE COUNTY TO SRN SCHOOLCRAFT. BEFORE CLOUDS INCREASE LATER IN THE NIGHT...THERE SHOULD BE AN OPPORTUNITY FOR TEMPS TO CRASH. LOWERED TEMPS TOWARD -10F IN THOSE AREAS. AS FOR PCPN...FORCING ASSOCIATED WITH SHORTWAVE MOVING E ACROSS THE CNTRL PLAINS WILL REMAIN WELL TO THE S THRU THE NIGHT. IN ADDITION...EVENING SOUNDINGS INDICATE A FAIR AMOUNT OF DRY AIR TO OVERCOME. HAVE THUS TRIMMED POPS OVER THE SRN FCST AREA OVERNIGHT. ONLY RETAINED LOW POPS NEAR LAKE MICHIGAN WHERE SOME LAKE EFFECT FLURRIES/-SHSN MAY DEVELOP LATE...MAINLY S OF KESC. && .PREV DISCUSSION (ISSUED AT 400 PM EST)... SHORT TERM (TNGT AND TUE)... WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER EASTERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA. A RIDGE IS OVER THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. A SHORTWAVE IS DIGGING OVER THE NORTHERN PLAINS AS IT SLIDES DOWN THE LEE OF THE WEST COAST RIDGE. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES REGION...WHILE A LOW IS DEEPENING OVER TEXAS. A WARM FRONT IS DEVELOPING OVER THE NORTHERN HIGH PLAINS. MOST OF THE U.P. STATIONS ARE REPORTING TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO. THE EXCEPTIONS ARE AREAS ALONG THE LAKE SUPERIOR SHORE WHERE TEMPERATURES REACH INTO THE TEENS. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH TUESDAY. WINDS WILL REMAIN FROM THE NORTH TONIGHT. TEMPERATURES DELTA-T`S CONTINUE TO BE COOL ENOUGH TO PRODUCE LAKE EFFECT SNOWS OVER AREA PRONE TO LES WITH A NORTH FLOW. THE SHORTWAVE OVER THE NORTHERN PLAINS WILL DEEPEN INTO A TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT AND SHIFT INTO THE UPPER MICHIGAN ON TUESDAY. GFS SHOWING WARM AIR ADVECTION AND A SLIGHT INCREASE IN SURFACE DEW POINT OVER THE AREA AS LOW LEVEL MOISTURE OUT OF THE CENTRAL PLAINS PUSH TOWARDS THE UPPER GREAT LAKES. 850MB TEMPERATURES WILL STILL REMAIN AROUND -16C STILL COOL ENOUGH OVER THE LAKES TO PRODUCE SOME LAKE EFFECT SNOW OVER THE SOUTHERN U.P. WHERE THERE WILL BE A SOUTHERLY FLOW. LONG TERM (TUE NGT THRU MON)... ON TUE NGT/WED...MOST MODELS HAVE CONTINUED TO TREND WEAKER WITH SHRTWV FCST TO SWING THRU ONTARIO AND ASSOCIATED COLD FROPA INTO THE UPR GRT LKS LATE TUE NGT AND WED DESPITE UPR PATTERN FEATURING HI AMPLITUDE RDG OVER WRN CAN THAT WOULD SUPPORT A MORE STRONGLY DIGGING SYS. GIVEN FVRBL UPR PATTERN...WL BLEND THE GFS WITH THE STRONGER 12Z UKMET FOR THIS SYS. THAT SCENARIO SUGS ASSOCIATED COLD FNT WL APRCH THE WRN ZNS AFT MIDNGT TUE NGT...SO MAINTAINED GOING CHC POPS IN THAT AREA WHERE UPSLOPE FLOW WL TEND TO OFFSET DRYNESS. THEN SOME LGT LES NEAR LK SUP ON WED WITH COLD AIR INTRUSION BEHIND COLD FROPA (H85 TEMPS FCST ON WED RANGES FM -20C TO -24C PER THE UKMET TO -16C TO -20C ON THE GFS). RELATIVELY SHALLOW...DRY NATURE OF COLD AIR INTRUSION AND GENERAL ACYC FLOW IN THE WAKE OF COLD FNT SHOULD LIMIT LES AMTS. EXACT FCST FOR WED NGT AND THU DEPENDS ON COMPLEX INTERACTION BTWN POLAR AND ARCTIC BRANCH DISTURBANCES OVER THE UPR MS VALLEY AND ASSOCIATED SFC LO DVLPMNT/FGEN ON ITS NRN FLANK. PER NCEP GUIDANCE...TRENDED TOWARD THE GFS HANDLING OF THIS INTERACTION BTWN ARCTIC AIR SURGING S FM CAN AND LO PRES DVLPG IN ADVANCE OF POLAR BRANCH SHRTWV. OPTED TO BUMP POPS UP TO HI LIKELY OVER THE SRN TIER LATE WED NGT/THU CLOSER TO LO PRES TRACK TO THE S. SHARP H85-7 FGEN AND UPR DVGC IN THE RRQ OF H3 JET MAX JUST S OF JAMES BAY JUSTIFIES POPS TOWARD THE HI END OF ENSEMBLE GUIDANCE. ELY FLOW OVER NRN LK MI WITH H85 TEMPS ARND -12C WL SUPPORT SOME LK ENHANCEMENT OVER THE SCNTRL WITH HIER QPF THERE. WITH SHARP FGEN TENDING TO ENHANCE LLVL CAD...TENDED TOWARD THE LOWER END OF MOS GUIDANCE FOR TEMPS. TIMING DIFFERENCES AS TO THE DEPARTURE SPEED OF SFC LO ON THU NGT AND TREND TOWARD TRANSITION TO PURE LES. SINCE 12Z GFS HAS TRENDED TOWARD THE 00Z ECMWF WITH FASTER EXIT OF THE LO...TENDED TO FOLLOW THAT TREND WITH FASTER END OF PCPN OVER THE S/TRANSITION TO LES NEAR LK SUP. THEN PERSISTENT LES ON FRI NEAR LK SUP WITH INFLUX OF VERY COLD AIR (GFS SHOWS H85 TEMPS SINKING TO ARND -25C). APRCH OF SHRTWV RDGING/SFC HI ON FRI NGT/SAT WL DIMINISH THESE SHSN. HEDGED TOWARD THE LOWER END OF MOS GUIDANCE FOR SAT MRNG LO TEMPS WITH ARRIVAL OF RDG AXIS/LIGHTER WINDS. NEXT CLIPPER LO DUE TO APRCH LATE SAT AND BRING CHC POPS...HIEST TO THE N...AS CLIPPER TRACKS ACRS LK SUP/ONTARIO ON SUN. TEMPS WL REBOUND TO NEAR NORMAL WITH FAIRLY STRG SW FLOW IN ADVANCE OF THIS SYS...BUT ARRIVAL OF REINFORCING SHRTWV/COLD FNT ON LATE SUN/MON WL TREND TEMPS DOWN AGAIN AND RESTART LES. COORDINATED WITH NCEP/APX/LOT/GRB/DLH. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... CONDITIONS ARE EXPECTED TO FLUCTUATE BTWN VFR AND MVFR (UPPER END MVFR CIGS) THRU THIS FCST PERIOD AT BOTH KCMX AND KSAW...THOUGH KCMX SHOULD TREND TO PREDOMINANT VFR LATER IN THE NIGHT THRU TUE AS LOW-LEVEL WINDS TAKE ON AN OVER LAND COMPONENT INSTEAD OF OVER WATER. AT KSAW...THERE SHOULD BE A PERIOD LATE IN THE NIGHT THRU TUE MORNING WITH VFR CONDITIONS. SE UPSLOPE FLOW OFF LAKE MICHIGAN SHOULD BRING MVFR CIGS BACK TO KSAW TUE AFTN. OCCASIONAL FLURRIES THRU THE EVENING HRS SHOULD NOT REDUCE VIS BLO VFR. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUESDAY NIGHT. THE GFS TAKES THE FRONT. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE UPPER LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. HEAVY FREEZING SPRAY IS LIKELY OVER AT PORTIONS OF THE LK ON WED NGT THRU SAT AS COLD AIR RETAINS ITS LOCK ON THE UPR GRT LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SHORT TERM DISCUSSION...DLG LONG TERM DISCUSSION...KC AVIATION...ROLFSON MARINE...DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 638 PM EST MON FEB 11 2008 UPDATED AVIATION DISCUSSION FOR 00Z TAFS .SHORT TERM (TNGT AND TUE ISSUED AT 400 PM EST)... WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER EASTERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA. A RIDGE IS OVER THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. A SHORTWAVE IS DIGGING OVER THE NORTHERN PLAINS AS IT SLIDES DOWN THE LEE OF THE WEST COAST RIDGE. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES REGION...WHILE A LOW IS DEEPENING OVER TEXAS. A WARM FRONT IS DEVELOPING OVER THE NORTHERN HIGH PLAINS. MOST OF THE U.P. STATIONS ARE REPORTING TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO. THE EXCEPTIONS ARE AREAS ALONG THE LAKE SUPERIOR SHORE WHERE TEMPERATURES REACH INTO THE TEENS. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH TUESDAY. WINDS WILL REMAIN FROM THE NORTH TONIGHT. TEMPERATURES DELTA-T`S CONTINUE TO BE COOL ENOUGH TO PRODUCE LAKE EFFECT SNOWS OVER AREA PRONE TO LES WITH A NORTH FLOW. THE SHORTWAVE OVER THE NORTHERN PLAINS WILL DEEPEN INTO A TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT AND SHIFT INTO THE UPPER MICHIGAN ON TUESDAY. GFS SHOWING WARM AIR ADVECTION AND A SLIGHT INCREASE IN SURFACE DEW POINT OVER THE AREA AS LOW LEVEL MOISTURE OUT OF THE CENTRAL PLAINS PUSH TOWARDS THE UPPER GREAT LAKES. 850MB TEMPERATURES WILL STILL REMAIN AROUND -16C STILL COOL ENOUGH OVER THE LAKES TO PRODUCE SOME LAKE EFFECT SNOW OVER THE SOUTHERN U.P. WHERE THERE WILL BE A SOUTHERLY FLOW. .LONG TERM (TUE NGT THRU MON)... ON TUE NGT/WED...MOST MODELS HAVE CONTINUED TO TREND WEAKER WITH SHRTWV FCST TO SWING THRU ONTARIO AND ASSOCIATED COLD FROPA INTO THE UPR GRT LKS LATE TUE NGT AND WED DESPITE UPR PATTERN FEATURING HI AMPLITUDE RDG OVER WRN CAN THAT WOULD SUPPORT A MORE STRONGLY DIGGING SYS. GIVEN FVRBL UPR PATTERN...WL BLEND THE GFS WITH THE STRONGER 12Z UKMET FOR THIS SYS. THAT SCENARIO SUGS ASSOCIATED COLD FNT WL APRCH THE WRN ZNS AFT MIDNGT TUE NGT...SO MAINTAINED GOING CHC POPS IN THAT AREA WHERE UPSLOPE FLOW WL TEND TO OFFSET DRYNESS. THEN SOME LGT LES NEAR LK SUP ON WED WITH COLD AIR INTRUSION BEHIND COLD FROPA (H85 TEMPS FCST ON WED RANGES FM -20C TO -24C PER THE UKMET TO -16C TO -20C ON THE GFS). RELATIVELY SHALLOW...DRY NATURE OF COLD AIR INTRUSION AND GENERAL ACYC FLOW IN THE WAKE OF COLD FNT SHOULD LIMIT LES AMTS. EXACT FCST FOR WED NGT AND THU DEPENDS ON COMPLEX INTERACTION BTWN POLAR AND ARCTIC BRANCH DISTURBANCES OVER THE UPR MS VALLEY AND ASSOCIATED SFC LO DVLPMNT/FGEN ON ITS NRN FLANK. PER NCEP GUIDANCE...TRENDED TOWARD THE GFS HANDLING OF THIS INTERACTION BTWN ARCTIC AIR SURGING S FM CAN AND LO PRES DVLPG IN ADVANCE OF POLAR BRANCH SHRTWV. OPTED TO BUMP POPS UP TO HI LIKELY OVER THE SRN TIER LATE WED NGT/THU CLOSER TO LO PRES TRACK TO THE S. SHARP H85-7 FGEN AND UPR DVGC IN THE RRQ OF H3 JET MAX JUST S OF JAMES BAY JUSTIFIES POPS TOWARD THE HI END OF ENSEMBLE GUIDANCE. ELY FLOW OVER NRN LK MI WITH H85 TEMPS ARND -12C WL SUPPORT SOME LK ENHANCEMENT OVER THE SCNTRL WITH HIER QPF THERE. WITH SHARP FGEN TENDING TO ENHANCE LLVL CAD...TENDED TOWARD THE LOWER END OF MOS GUIDANCE FOR TEMPS. TIMING DIFFERENCES AS TO THE DEPARTURE SPEED OF SFC LO ON THU NGT AND TREND TOWARD TRANSITION TO PURE LES. SINCE 12Z GFS HAS TRENDED TOWARD THE 00Z ECMWF WITH FASTER EXIT OF THE LO...TENDED TO FOLLOW THAT TREND WITH FASTER END OF PCPN OVER THE S/TRANSITION TO LES NEAR LK SUP. THEN PERSISTENT LES ON FRI NEAR LK SUP WITH INFLUX OF VERY COLD AIR (GFS SHOWS H85 TEMPS SINKING TO ARND -25C). APRCH OF SHRTWV RDGING/SFC HI ON FRI NGT/SAT WL DIMINISH THESE SHSN. HEDGED TOWARD THE LOWER END OF MOS GUIDANCE FOR SAT MRNG LO TEMPS WITH ARRIVAL OF RDG AXIS/LIGHTER WINDS. NEXT CLIPPER LO DUE TO APRCH LATE SAT AND BRING CHC POPS...HIEST TO THE N...AS CLIPPER TRACKS ACRS LK SUP/ONTARIO ON SUN. TEMPS WL REBOUND TO NEAR NORMAL WITH FAIRLY STRG SW FLOW IN ADVANCE OF THIS SYS...BUT ARRIVAL OF REINFORCING SHRTWV/COLD FNT ON LATE SUN/MON WL TREND TEMPS DOWN AGAIN AND RESTART LES. COORDINATED WITH NCEP/APX/LOT/GRB/DLH. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... CONDITIONS ARE EXPECTED TO FLUCTUATE BTWN VFR AND MVFR (UPPER END MVFR CIGS) THRU THIS FCST PERIOD AT BOTH KCMX AND KSAW...THOUGH KCMX SHOULD TREND TO PREDOMINANT VFR LATER IN THE NIGHT THRU TUE AS LOW-LEVEL WINDS TAKE ON AN OVER LAND COMPONENT INSTEAD OF OVER WATER. AT KSAW...THERE SHOULD BE A PERIOD LATE IN THE NIGHT THRU TUE MORNING WITH VFR CONDITIONS. SE UPSLOPE FLOW OFF LAKE MICHIGAN SHOULD BRING MVFR CIGS BACK TO KSAW TUE AFTN. OCCASIONAL FLURRIES THRU THE EVENING HRS SHOULD NOT REDUCE VIS BLO VFR. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUESDAY NIGHT. THE GFS TAKES THE FRONT. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE UPPER LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. HEAVY FREEZING SPRAY IS LIKELY OVER AT PORTIONS OF THE LK ON WED NGT THRU SAT AS COLD AIR RETAINS ITS LOCK ON THE UPR GRT LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SHORT TERM DISCUSSION...DLG LONG TERM DISCUSSION...KC AVIATION...ROLFSON MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 400 PM EST MON FEB 11 2008 .SHORT TERM DISCUSSION (TNGT AND TUE)... WATER VAPOR IMAGERY AND RUC SHOWING A SHORTWAVE OVER EASTERN ONTARIO EMBEDDED IN A LONGWAVE TROUGH OVER EASTERN CANADA. A RIDGE IS OVER THE PACIFIC NORTHWEST AND SOUTHWEST CANADA. A SHORTWAVE IS DIGGING OVER THE NORTHERN PLAINS AS IT SLIDES DOWN THE LEE OF THE WEST COAST RIDGE. SURFACE ANALYSIS DEPICTS A LARGE HIGH OVER THE UPPER GREAT LAKES REGION...WHILE A LOW IS DEEPENING OVER TEXAS. A WARM FRONT IS DEVELOPING OVER THE NORTHERN HIGH PLAINS. MOST OF THE U.P. STATIONS ARE REPORTING TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO. THE EXCEPTIONS ARE AREAS ALONG THE LAKE SUPERIOR SHORE WHERE TEMPERATURES REACH INTO THE TEENS. THE SURFACE RIDGE WILL REMAIN OVER THE FORECAST AREA THROUGH TUESDAY. WINDS WILL REMAIN FROM THE NORTH TONIGHT. TEMPERATURES DELTA-T`S CONTINUE TO BE COOL ENOUGH TO PRODUCE LAKE EFFECT SNOWS OVER AREA PRONE TO LES WITH A NORTH FLOW. THE SHORTWAVE OVER THE NORTHERN PLAINS WILL DEEPEN INTO A TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY TONIGHT AND SHIFT INTO THE UPPER MICHIGAN ON TUESDAY. GFS SHOWING WARM AIR ADVECTION AND A SLIGHT INCREASE IN SURFACE DEW POINT OVER THE AREA AS LOW LEVEL MOISTURE OUT OF THE CENTRAL PLAINS PUSH TOWARDS THE UPPER GREAT LAKES. 850MB TEMPERATURES WILL STILL REMAIN AROUND -16C STILL COOL ENOUGH OVER THE LAKES TO PRODUCE SOME LAKE EFFECT SNOW OVER THE SOUTHERN U.P. WHERE THERE WILL BE A SOUTHERLY FLOW. .LONG TERM DISCUSSION (TUE NGT THRU MON)... ON TUE NGT/WED...MOST MODELS HAVE CONTINUED TO TREND WEAKER WITH SHRTWV FCST TO SWING THRU ONTARIO AND ASSOCIATED COLD FROPA INTO THE UPR GRT LKS LATE TUE NGT AND WED DESPITE UPR PATTERN FEATURING HI AMPLITUDE RDG OVER WRN CAN THAT WOULD SUPPORT A MORE STRONGLY DIGGING SYS. GIVEN FVRBL UPR PATTERN...WL BLEND THE GFS WITH THE STRONGER 12Z UKMET FOR THIS SYS. THAT SCENARIO SUGS ASSOCIATED COLD FNT WL APRCH THE WRN ZNS AFT MIDNGT TUE NGT...SO MAINTAINED GOING CHC POPS IN THAT AREA WHERE UPSLOPE FLOW WL TEND TO OFFSET DRYNESS. THEN SOME LGT LES NEAR LK SUP ON WED WITH COLD AIR INTRUSION BEHIND COLD FROPA (H85 TEMPS FCST ON WED RANGES FM -20C TO -24C PER THE UKMET TO -16C TO -20C ON THE GFS). RELATIVELY SHALLOW...DRY NATURE OF COLD AIR INTRUSION AND GENERAL ACYC FLOW IN THE WAKE OF COLD FNT SHOULD LIMIT LES AMTS. EXACT FCST FOR WED NGT AND THU DEPENDS ON COMPLEX INTERACTION BTWN POLAR AND ARCTIC BRANCH DISTURBANCES OVER THE UPR MS VALLEY AND ASSOCIATED SFC LO DVLPMNT/FGEN ON ITS NRN FLANK. PER NCEP GUIDANCE...TRENDED TOWARD THE GFS HANDLING OF THIS INTERACTION BTWN ARCTIC AIR SURGING S FM CAN AND LO PRES DVLPG IN ADVANCE OF POLAR BRANCH SHRTWV. OPTED TO BUMP POPS UP TO HI LIKELY OVER THE SRN TIER LATE WED NGT/THU CLOSER TO LO PRES TRACK TO THE S. SHARP H85-7 FGEN AND UPR DVGC IN THE RRQ OF H3 JET MAX JUST S OF JAMES BAY JUSTIFIES POPS TOWARD THE HI END OF ENSEMBLE GUIDANCE. ELY FLOW OVER NRN LK MI WITH H85 TEMPS ARND -12C WL SUPPORT SOME LK ENHANCEMENT OVER THE SCNTRL WITH HIER QPF THERE. WITH SHARP FGEN TENDING TO ENHANCE LLVL CAD...TENDED TOWARD THE LOWER END OF MOS GUIDANCE FOR TEMPS. TIMING DIFFERENCES AS TO THE DEPARTURE SPEED OF SFC LO ON THU NGT AND TREND TOWARD TRANSITION TO PURE LES. SINCE 12Z GFS HAS TRENDED TOWARD THE 00Z ECMWF WITH FASTER EXIT OF THE LO...TENDED TO FOLLOW THAT TREND WITH FASTER END OF PCPN OVER THE S/TRANSITION TO LES NEAR LK SUP. THEN PERSISTENT LES ON FRI NEAR LK SUP WITH INFLUX OF VERY COLD AIR (GFS SHOWS H85 TEMPS SINKING TO ARND -25C). APRCH OF SHRTWV RDGING/SFC HI ON FRI NGT/SAT WL DIMINISH THESE SHSN. HEDGED TOWARD THE LOWER END OF MOS GUIDANCE FOR SAT MRNG LO TEMPS WITH ARRIVAL OF RDG AXIS/LIGHTER WINDS. NEXT CLIPPER LO DUE TO APRCH LATE SAT AND BRING CHC POPS...HIEST TO THE N...AS CLIPPER TRACKS ACRS LK SUP/ONTARIO ON SUN. TEMPS WL REBOUND TO NEAR NORMAL WITH FAIRLY STRG SW FLOW IN ADVANCE OF THIS SYS...BUT ARRIVAL OF REINFORCING SHRTWV/COLD FNT ON LATE SUN/MON WL TREND TEMPS DOWN AGAIN AND RESTART LES. COORDINATED WITH NCEP/APX/LOT/GRB/DLH. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... CONDITIONS ARE SLOWLY IMPROVING AT KCMX. OCCASIONAL REDUCED VSBYS IS MAINLY DUE TO THE FINE NATURE OF THE SNOW AND IN REALITY NOT MUCH IS ACCUMULATING. WILL CONTINUE WITH IMPROVEMENT THIS AFTERNOON WHEN THE WIND TURNS NORTHERLY. AT SAW...MVFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE DAY. IN FACT...AS THE WINDS TURN MORE NORTHERLY...SOME OF THE LAKE EFFECT BANDS MAY MOVE ONSHORE ACROSS EASTERN MARQUETTE COUNTY. HOWEVER...AT THE SAME TIME THE INVERSION WILL BE CRASHING SO THE SNOW SHOULD ONLY REDUCE VSBYS TO 3-5SM AT TIMES. ALL SITES SHOULD BECOME VFR LATE THIS EVENING AS THE HIGH BUILDS OVERHEAD. AS A LOW MOVES INTO LOWER MICHIGAN TUESDAY MORNING...A DECK OF LOW CLOUDS AND SOME SNOW SHOULD SPREAD INTO THE KSAW AREA. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUESDAY NIGHT. THE GFS TAKES THE FRONT. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE UPPER LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. HEAVY FREEZING SPRAY IS LIKELY OVER AT PORTIONS OF THE LK ON WED NGT THRU SAT AS COLD AIR RETAINS ITS LOCK ON THE UPR GRT LKS. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SHORT TERM DISCUSSION...DLG LONG TERM DISCUSSION...KC AVIATION...DLG MARINE...DLG mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1226 PM EST MON FEB 11 2008 UPDATE FOR AVIATION... .DISCUSSION... TODAY THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE WIND CHILL POTENTIAL FOR THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC SHOWING A LOW OVER EAST CENTRAL ONTARIO SWEEPING THROUGH THE BASE OF A LONGWAVE TROUGH THAT BLANKETS MUCH OF EASTERN CANADA. A RIDGE IS MOVING ASHORE OVER THE PACIFIC NORTHWEST. WEAK SHORTWAVES ARE MOVING THROUGH MANITOBA AND SOUTH DAKOTA. SURFACE ANALYSIS DEPICTS A LARGE RIDGE OVER WESTERN ONTARIO AND THE UPPER GREAT LAKES REGION. A WEAK SURFACE TROUGH EXTENDS FROM SOUTHEAST ONTARIO INTO THE EASTERN U.P. TO THE WEST A LOW PRESSURE CENTER CONTINUES TO DEVELOP OVER THE CENTRAL HIGH PLAINS. WINDS OVER THE AREA CONTINUE TO DECREASE AS THE RIDGE MOVES OVER THE AREA. THE SHORTWAVE OVER MANITOBA WILL SLIDE DOWN THE LEE OF THE RIDGE INTO NORTHERN MINNESOTA THIS AFTERNOON AS THE EASTERN ONTARIO SHORTWAVE SHIFTS INTO WESTERN QUEBEC. THE SURFACE RIDGE WILL EXPAND ACROSS THE REST OF THE GREAT LAKES REGION FORCING THE LOW OVER THE CENTRAL HIGH PLAINS SOUTHEAST INTO TEXAS. WITH THE RIDGE EXPANDING OVER THE AREA...THE WINDS AND WIND CHILL HAVE DECREASED BELOW ADVISORY CRITERIA. THUS WILL ALLOW ALL THE WIND CHILL ADVISORY TO EXPIRE. THE LAKE-850MB DELTA-T`S WILL CONTINUE TO BE AROUND 23C WHICH WILL PRODUCE LAKE EFFECT SNOWS OVER THE FORECAST AREA AS VERFIED BY SATELLITE AND KMQT-88D. SURFACE REPORTS FOR OUR SNOW NETWORK INDICATE SNOWFALL 4 INCHES OR LESS CONTINUE OVER THE AREA IN A 24 HOUR PERIOD. THUS WITH THE COLD TEMPERATURES THE SNOW WILL BE VERY FINE AND WHICH WILL LIMIT ACCUMULATION. PLAN TO UPDATE THE ZFP FOR WORDING AND TO DROP THE MENTION OF WIND CHILL FOR THE REST OF TODAY. TONIGHT...AND LATER WITH NE FLOW DOMINATING AND HIGH PRESSURE OVERHEAD KEEPING DRY AIR IN PLACE A BIT LONGER...HAVE DECREASED THE APPROACHING MID TO HIGH CLOUDS FOR THE OVERNIGHT HOURS. THE LOW...CURRENTLY DEVELOPING OVER NEW MEXICO AND WEST TEXAS WILL SHIFT NORTHEASTWARD TO NORTHEASTERN ARKANSAS BY 12Z TUESDAY...BEFORE MOVING TO THE APPALACHIANS BY WEDNESDAY MORNING. MOST OF THE PRECIPITATION WILL FALL TO OUR SOUTH...SO HAVE LIMITED POPS IN FOR THIS SYSTEM MAINLY SOUTH THROUGH TUESDAY AFTERNOON. ANOTHER LOW TO OUR NORTHWEST WILL MOVE TO WESTERN HUDSON BAY TRAILING A COLD FRONT THOUGH CENTRAL MANITOBA...AND FINALLY OVER LAKE SUPERIOR BY 06Z WEDNESDAY. ONCE AGAIN...ONLY LIGHT SNOW AMOUNTS ARE FIGURED AND MAINLY ACROSS THE NORTHERN HALF OF UPPER MICHIGAN. THE NEXT SYSTEM WITH THE POTENTIAL FOR MORE SIGNIFICANT PRECIPITATION AMOUNTS...AND A GOOD CHANCE OF SNOW IN GENERAL WILL COME IN FOR LATE WEDNESDAY NIGHT AND CONTINUE ITS INFLUENCE THROUGH THE END OF THE WORKWEEK. THE 00Z GFS HAS TRANSFORMED SLIGHTLY WITH THIS SYSTEM. THE SURFACE LOW THAT WAS OVER NW LAKE HURON AT 18Z FRIDAY OFF OF THE 18Z GFS...IS NOW ABOUT 20 MILES NW OF THAT LOCATION AT 06Z FRIDAY. ALL IN ALL...THE LATEST 00Z RUN OF THE GFS IS QUICKER AND SLIGHTLY NORTHWARD WITH RESPECT TO THE TRACK OF THE SURFACE LOW OVER THE NORTHERN GREAT LAKES REGION FOR THE END OF THE WORKWEEK. WHAT THIS MAY MEAN FOR UPPER MICHIGAN IS NORTHWESTERLY WINDS HOLDING ON A BIT LONGER...OR FROM FRIDAY MORNING TO 06Z-12Z SATURDAY. THE 00Z NAM WAS ALSO A BIT FASTER THAN ITS PREVIOUS RUN. OVERALL...THE GFS HAS TRENDED MORE CONSISTENT WITH THE ECMWF...ALTHOUGH A LITTLE NORTH WITH ITS TRACK OF THE 500MB LOW. WITH HEDGE THE FORECAST MORE IN LINE WITH THE LATEST 00Z GFS SOLUTION. DID NOT MAKE ANY CHANGES TO THE POP FORECAST AFTER 06Z THURSDAY...DUE TO THE VARIABILITY IN THE FORECAST MODELS. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... CONDITIONS ARE SLOWLY IMPROVING AT KCMX. OCCASIONAL REDUCED VSBYS IS MAINLY DUE TO THE FINE NATURE OF THE SNOW AND IN REALITY NOT MUCH IS ACCUMULATING. WILL CONTINUE WITH IMPROVEMENT THIS AFTERNOON WHEN THE WIND TURNS NORTHERLY. AT SAW...MVFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE DAY. IN FACT...AS THE WINDS TURN MORE NORTHERLY...SOME OF THE LAKE EFFECT BANDS MAY MOVE ONSHORE ACROSS EASTERN MARQUETTE COUNTY. HOWEVER...AT THE SAME TIME THE INVERSION WILL BE CRASHING SO THE SNOW SHOULD ONLY REDUCE VSBYS TO 3-5SM AT TIMES. ALL SITES SHOULD BECOME VFR LATE THIS EVENING AS THE HIGH BUILDS OVERHEAD. AS A LOW MOVES INTO LOWER MICHIGAN TUESDAY MORNING...A DECK OF LOW CLOUDS AND SOME SNOW SHOULD SPREAD INTO THE KSAW AREA. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... ARCTIC HIGH PRESSURE WILL BUILD RAPIDLY ACROSS THE WESTERN GREAT LAKES TODAY. WILL DROP ALL GALE WARNINGS WITH THIS ISSUANCE. WILL NEED TO KEEP HEAVY FREEZING SPRAY THIS MORNING BUT THAT SHOULD DIMINISH AS THE HIGH BUILDS INTO THE AREA. WINDS ACROSS LAKE SUPERIOR WILL QUICKLY SUBSIDE TODAY TO LESS THAN 10 KT BY EVENING WITH THE HIGH OVERHEAD. WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUE AFTN/NIGHT. THE NAM AND GFS ARE IN DISAGREEMENT WITH REGARDS TO FRONTAL POSITION BY WED EVENING...WITH THE GFS TAKING THE FRONT THROUGH LAKE SUPERIOR WHILE THE NAM HOLDS THE FRONT UP JUST NORTH OF THE LAKE. AT THIS TIME THE GFS IS PREFERRED GIVEN IT/S AGREEMENT IN THE ECMWF. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE WESTERN LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ162-263>267. LAKE MICHIGAN...HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ248-250. && $$ DISCUSSION (TODAY)...DLG DISCUSSION (TONIGHT AND LATER)...KF AVIATION...MRD MARINE...MRD mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1126 AM EST MON FEB 11 2008 .DISCUSSION... .TODAY... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE WIND CHILL POTENTIAL FOR THIS AFTERNOON. WATER VAPOR IMAGERY AND RUC SHOWING A LOW OVER EAST CENTRAL ONTARIO SWEEPING THROUGH THE BASE OF A LONGWAVE TROUGH THAT BLANKETS MUCH OF EASTERN CANADA. A RIDGE IS MOVING ASHORE OVER THE PACIFIC NORTHWEST. WEAK SHORTWAVES ARE MOVING THROUGH MANITOBA AND SOUTH DAKOTA. SURFACE ANALYSIS DEPICTS A LARGE RIDGE OVER WESTERN ONTARIO AND THE UPPER GREAT LAKES REGION. A WEAK SURFACE TROUGH EXTENDS FROM SOUTHEAST ONTARIO INTO THE EASTERN U.P. TO THE WEST A LOW PRESSURE CENTER CONTINUES TO DEVELOP OVER THE CENTRAL HIGH PLAINS. WINDS OVER THE AREA CONTINUE TO DECREASE AS THE RIDGE MOVES OVER THE AREA. THE SHORTWAVE OVER MANITOBA WILL SLIDE DOWN THE LEE OF THE RIDGE INTO NORTHERN MINNESOTA THIS AFTERNOON AS THE EASTERN ONTARIO SHORTWAVE SHIFTS INTO WESTERN QUEBEC. THE SURFACE RIDGE WILL EXPAND ACROSS THE REST OF THE GREAT LAKES REGION FORCING THE LOW OVER THE CENTRAL HIGH PLAINS SOUTHEAST INTO TEXAS. WITH THE RIDGE EXPANDING OVER THE AREA...THE WINDS AND WIND CHILL HAVE DECREASED BELOW ADVISORY CRITERIA. THUS WILL ALLOW ALL THE WIND CHILL ADVISORY TO EXPIRE. THE LAKE-850MB DELTA-T`S WILL CONTINUE TO BE AROUND 23C WHICH WILL PRODUCE LAKE EFFECT SNOWS OVER THE FORECAST AREA AS VERFIED BY SATELLITE AND KMQT-88D. SURFACE REPORTS FOR OUR SNOW NETWORK INDICATE SNOWFALL 4 INCHES OR LESS CONTINUE OVER THE AREA IN A 24 HOUR PERIOD. THUS WITH THE COLD TEMPERATURES THE SNOW WILL BE VERY FINE AND WHICH WILL LIMIT ACCUMULATION. PLAN TO UPDATE THE ZFP FOR WORDING AND TO DROP THE MENTION OF WIND CHILL FOR THE REST OF TODAY. .TONIGHT...AND LATER WITH NE FLOW DOMINATING AND HIGH PRESSURE OVERHEAD KEEPING DRY AIR IN PLACE A BIT LONGER...HAVE DECREASED THE APPROACHING MID TO HIGH CLOUDS FOR THE OVERNIGHT HOURS. THE LOW...CURRENTLY DEVELOPING OVER NEW MEXICO AND WEST TEXAS WILL SHIFT NORTHEASTWARD TO NORTHEASTERN ARKANSAS BY 12Z TUESDAY...BEFORE MOVING TO THE APPALACHIANS BY WEDNESDAY MORNING. MOST OF THE PRECIPITATION WILL FALL TO OUR SOUTH...SO HAVE LIMITED POPS IN FOR THIS SYSTEM MAINLY SOUTH THROUGH TUESDAY AFTERNOON. ANOTHER LOW TO OUR NORTHWEST WILL MOVE TO WESTERN HUDSON BAY TRAILING A COLD FRONT THOUGH CENTRAL MANITOBA...AND FINALLY OVER LAKE SUPERIOR BY 06Z WEDNESDAY. ONCE AGAIN...ONLY LIGHT SNOW AMOUNTS ARE FIGURED AND MAINLY ACROSS THE NORTHERN HALF OF UPPER MICHIGAN. THE NEXT SYSTEM WITH THE POTENTIAL FOR MORE SIGNIFICANT PRECIPITATION AMOUNTS...AND A GOOD CHANCE OF SNOW IN GENERAL WILL COME IN FOR LATE WEDNESDAY NIGHT AND CONTINUE ITS INFLUENCE THROUGH THE END OF THE WORKWEEK. THE 00Z GFS HAS TRANSFORMED SLIGHTLY WITH THIS SYSTEM. THE SURFACE LOW THAT WAS OVER NW LAKE HURON AT 18Z FRIDAY OFF OF THE 18Z GFS...IS NOW ABOUT 20 MILES NW OF THAT LOCATION AT 06Z FRIDAY. ALL IN ALL...THE LATEST 00Z RUN OF THE GFS IS QUICKER AND SLIGHTLY NORTHWARD WITH RESPECT TO THE TRACK OF THE SURFACE LOW OVER THE NORTHERN GREAT LAKES REGION FOR THE END OF THE WORKWEEK. WHAT THIS MAY MEAN FOR UPPER MICHIGAN IS NORTHWESTERLY WINDS HOLDING ON A BIT LONGER...OR FROM FRIDAY MORNING TO 06Z-12Z SATURDAY. THE 00Z NAM WAS ALSO A BIT FASTER THAN ITS PREVIOUS RUN. OVERALL...THE GFS HAS TRENDED MORE CONSISTENT WITH THE ECMWF...ALTHOUGH A LITTLE NORTH WITH ITS TRACK OF THE 500MB LOW. WITH HEDGE THE FORECAST MORE IN LINE WITH THE LATEST 00Z GFS SOLUTION. DID NOT MAKE ANY CHANGES TO THE POP FORECAST AFTER 06Z THURSDAY...DUE TO THE VARIABILITY IN THE FORECAST MODELS. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... CONDITIONS ARE FINALLY STARTING TO IMPROVE AT CMX. ALTHOUGH VSBYS ARE STILL IFR...CIGS ARE NOW MVFR. AM THINKING THAT THE REDUCED VSBYS IS MAINLY DUE TO THE FINE NATURE OF THE SNOW AND IN REALITY NOT MUCH IS ACCUMULATING. WILL CONTINUE WITH IMPROVEMENT TODAY AT CMX...ESPECIALLY THIS AFTERNOON WHEN THE WIND TURNS NORTHERLY. AT SAW...MVFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE DAY. IN FACT...AS THE WINDS TURN MORE NORTHERLY...SOME OF THE LAKE EFFECT BANDS MAY MOVE ONSHORE ACROSS EASTERN MARQUETTE COUNTY BY AFTERNOON. HOWEVER...AT THE SAME TIME THE INVERSION WILL BE CRASHING SO THE SNOW SHOULD ONLY REDUCE VSBYS TO 3-5SM AT TIMES. ALL SITES SHOULD BECOME VFR THIS EVENING AS THE HIGH BUILDS OVERHEAD. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... ARCTIC HIGH PRESSURE WILL BUILD RAPIDLY ACROSS THE WESTERN GREAT LAKES TODAY. WILL DROP ALL GALE WARNINGS WITH THIS ISSUANCE. WILL NEED TO KEEP HEAVY FREEZING SPRAY THIS MORNING BUT THAT SHOULD DIMINISH AS THE HIGH BUILDS INTO THE AREA. WINDS ACROSS LAKE SUPERIOR WILL QUICKLY SUBSIDE TODAY TO LESS THAN 10 KT BY EVENING WITH THE HIGH OVERHEAD. WILL LIKELY HAVE A LAND BREEZE TO CONTEND WITH TONIGHT WITH THE HIGH OVERHEAD AND COLD TEMPS ACROSS INLAND AREAS. THE HIGH QUICKLY SHIFTS EAST OF THE LAKES ON TUESDAY...GIVING WAY TO A COLD FRONT APPROACHING FROM THE WEST TUE AFTN/NIGHT. THE NAM AND GFS ARE IN DISAGREEMENT WITH REGARDS TO FRONTAL POSITION BY WED EVENING...WITH THE GFS TAKING THE FRONT THROUGH LAKE SUPERIOR WHILE THE NAM HOLDS THE FRONT UP JUST NORTH OF THE LAKE. AT THIS TIME THE GFS IS PREFERRED GIVEN IT/S AGREEMENT IN THE ECMWF. WILL KEEP WINDS 15-25 KT WITH THE FRONTAL PASSAGE...BUT IT COULD APPROACH 30 KT WED AFTN. ANOTHER LOW MOVES ALONG THE FRONT AND INTO THE WESTERN LAKES BY THU MORNING. NUMEROUS MODEL DIFFERENCES...AND DEPENDING ON THE EXACT TRACK 30KT WIND IS POSSIBLE THU. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...NONE. LAKE SUPERIOR...HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LSZ162-263>267. LAKE MICHIGAN...HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ248-250. && $$ DISCUSSION (TODAY)...DLG DISCUSSION (TONIGHT AND LATER)...KF AVIATION...MRD MARINE...MRD mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1015 PM CST MON FEB 11 2008 .UPDATED FOR AVIATION DISCUSSION BELOW... .DISCUSSION... EARLY AFTERNOON SATELLITE IMAGERY SHOWS A SHORTWAVE OVER CENTRAL NEBRASKA...WITH ANOTHER WAVE RIDING ON ITS HEELS OVER SOUTHWESTERN SOUTH DAKOTA. RUC/NAM/GFS MODELS PROG THESE TWO WAVES TO MERGE THIS EVENING...AND TRACK ACROSS IOWA AND MISSOURI. THE MAIN FRONTOGENETIC FORCING SLIDES ALONG/SOUTH OF THE MN/IA BORDER THIS EVENING...AND THEN LIFTS ACROSS SERN MN OVERNIGHT AND EARLY TUESDAY MORNING. IT WILL BE A TIGHT SNOWFALL GRADIENT...WITH THE HIGHEST AMOUNTS /1 TO 2 INCHES/ STILL APPEARING POSSIBLE ALONG/SOUTH OF THE INTERSTATE 90 CORRIDOR. NOT ENOUGH TO LEAVE THE SNOW ADVISORY IN EFFECT THROUGH TUESDAY MORNING...SO HAVE CANCELLED THE ENTIRE ADVISORY. DRIER EASTERLY AIRFLOW IN THE MID LEVEL AHEAD OF THE SHORT WAVE HAS LIMITED THE POTENTIAL FOR SUBSTANTIAL SNOWFALL OVER THE FAR SOUTH TONIGHT. SNOW WILL COME TO AN END ACROSS SOUTHEAST MN BY TUESDAY AFTERNOON...ALTHOUGH TEMPERATURES WILL REMAIN WELL BELOW NORMAL...WITH HIGHS RANGING BETWEEN 10 AND 20 DEGREES BELOW NORMAL. A STRONGER SHORTWAVE IS STILL ON TRACK TO DIVE FROM SOUTHERN CANADA ACROSS THE DAKOTAS ON WEDNESDAY...WHILE THE ASSOCIATED SURFACE TROUGH MOVES FROM THE DAKOTAS ACROSS SOUTHERN MN. PREFER THE GFS/ECMWF OVER THE NAM FOR THIS SYSTEM...SO HAVE INCREASED POPS ACROSS THE ENTIRE FORECAST AREA TO THE LIKELY CATEGORY ON WEDNESDAY NIGHT AND THURSDAY MORNING. THIS SYSTEM APPEARS TO HAVE THE POTENTIAL TO BRING AT LEAST ADVISORY CRITERIA SNOWFALL /3 TO 6 INCHES/ TO AT LEAST A PORTION OF THE CWA. ANOTHER NORTHERN STREAM WAVE IS EXPECTED TO PLUNGE INTO THE UPPER MIDWEST ON SATURDAY AND SATURDAY NIGHT...DURING WHICH 20 POPS HAVE BEEN MAINTAINED. TEMPERATURES ARE EXPECTED TO MODERATE INTO THE 20S FOR THE UPCOMING WEEKEND. && .AVIATION... /06Z TAF ISSUANCE/ VFR CIGS CONTINUE ACROSS THE REGION. DRY SURFACE HIGH CONTINUES TO HOLD SNOW AT BAY...WITH THE MAIN SHOW ACROSS FAR SOUTHERN MN. SOME FLURRY ACTIVITY MOVING THROUGH CENTRAL MN...AND MAY YET GENERATE A FLURRY AT MSP BEFORE SYSTEM/TROF MOVES THROUGH. WILL MAINTAIN VFR AT ALL BUT AXN/RWF DURING THE NIGHT. THE BEST SHOT OF SNOW/MVFR CIG/VSBY COMING AT RWF BEFORE 12Z TUE. MAY SEE SOME BREAKS DEVELOPING IN CLOUD COVER PER 00Z NAM GUIDANCE BEFORE NEXT DEVELOPING SFC TROUGH MOVES EAST ACROSS THE DAKOTAS. THIS WILL LIKELY LIFT SOME MVFR CIGS NORTH ACROSS SOUTH DAKOTA AND WESTERN MN LATE IN THE DAY TUESDAY AS SOUTHERLY FLOW DEVELOPS. WILL HOLD ONTO MENTION OF MFVR CIGS DEVELOPING FARTHER EAST AFTER 02Z WED PER GUIDANCE. 21Z SREF WAS INDICATING INCREASING PROBABILITIES OF CIGS < 3K FT DEVELOPING TUE NIGHT AS WELL. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 707 PM CST MON FEB 11 2008 .DISCUSSION... EARLY AFTERNOON SATELLITE IMAGERY SHOWS A SHORTWAVE OVER CENTRAL NEBRASKA...WITH ANOTHER WAVE RIDING ON ITS HEELS OVER SOUTHWESTERN SOUTH DAKOTA. RUC/NAM/GFS MODELS PROG THESE TWO WAVES TO MERGE THIS EVENING...AND TRACK ACROSS IOWA AND MISSOURI. THE MAIN FRONTOGENETIC FORCING SLIDES ALONG/SOUTH OF THE MN/IA BORDER THIS EVENING...AND THEN LIFTS ACROSS SERN MN OVERNIGHT AND EARLY TUESDAY MORNING. IT WILL BE A TIGHT SNOWFALL GRADIENT...WITH THE HIGHEST AMOUNTS /1 TO 2 INCHES/ STILL APPEARING POSSIBLE ALONG/SOUTH OF THE INTERSTATE 90 CORRIDOR. NOT ENOUGH TO LEAVE THE SNOW ADVISORY IN EFFECT THROUGH TUESDAY MORNING...SO HAVE CANCELLED THE ENTIRE ADVISORY. DRIER EASTERLY AIRFLOW IN THE MID LEVEL AHEAD OF THE SHORT WAVE HAS LIMITED THE POTENTIAL FOR SUBSTANTIAL SNOWFALL OVER THE FAR SOUTH TONIGHT. SNOW WILL COME TO AN END ACROSS SOUTHEAST MN BY TUESDAY AFTERNOON...ALTHOUGH TEMPERATURES WILL REMAIN WELL BELOW NORMAL...WITH HIGHS RANGING BETWEEN 10 AND 20 DEGREES BELOW NORMAL. A STRONGER SHORTWAVE IS STILL ON TRACK TO DIVE FROM SOUTHERN CANADA ACROSS THE DAKOTAS ON WEDNESDAY...WHILE THE ASSOCIATED SURFACE TROUGH MOVES FROM THE DAKOTAS ACROSS SOUTHERN MN. PREFER THE GFS/ECMWF OVER THE NAM FOR THIS SYSTEM...SO HAVE INCREASED POPS ACROSS THE ENTIRE FORECAST AREA TO THE LIKELY CATEGORY ON WEDNESDAY NIGHT AND THURSDAY MORNING. THIS SYSTEM APPEARS TO HAVE THE POTENTIAL TO BRING AT LEAST ADVISORY CRITERIA SNOWFALL /3 TO 6 INCHES/ TO AT LEAST A PORTION OF THE CWA. ANOTHER NORTHERN STREAM WAVE IS EXPECTED TO PLUNGE INTO THE UPPER MIDWEST ON SATURDAY AND SATURDAY NIGHT...DURING WHICH 20 POPS HAVE BEEN MAINTAINED. TEMPERATURES ARE EXPECTED TO MODERATE INTO THE 20S FOR THE UPCOMING WEEKEND. && .AVIATION... /00Z TAF ISSUANCE/ VFR CIGS CONTINUE INTO THE EVENING ACROSS THE REGION. NOT MUCH IN THE WAY OF WEATHER EXPECTED OVER EC MN AND WC WI AS DRY SURFACE HIGH SHOULD MAINTAIN FIRM GRIP HERE. DID MENTION SOME MVFR CIG/VSBY THROUGH ABOUT 07Z AT MSP. MAIN SHORT WAVE TROUGH SHOULD TRAVEL SOUTH ACROSS NE/IA REGION DURING THE NIGHT WITH THE BEST FORCING FOR SNOW FOUND HERE. TROUGH AXIS IN EASTERN DAKOTAS GENERATING SNOW OVER NORTHWEST/INTO WC MN AT THIS TIME AND WILL LIKELY AFFECT AXN/STC REGION THROUGH ABOUT 06Z...SO MENTION SOME MVFR CIGS/VSBYS HERE. OTHERWISE...HIT RWF HARDEST WITH IFR CIG/SNOW DEVELOPING THIS EVENING...MOVING OUT LATER TONIGHT. IF SHORT WAVE DOES NOT PROVIDE ENOUGH SUBSIDENCE BEHIND IT TUESDAY AFTERNOON...COULD MAINTAIN SOME MVFR CIGS OVER REGION AS FLOW BECOMES SOUTHERLY AHEAD OF NEXT WEATHER SYSTEM. OPTED TO FOLLOW GUIDANCE ON THIS END FOR NOW. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 744 PM CST TUE FEB 12 2008 .UPDATE... JUST SENT OUT AN UPDATE TO FINE TUNE CLEARING TREND...AND TO LWR TEMPS AS SVRL LOCATIONS WERE ALREADY CLOSE TO THEIR OVERNIGHT MIN. USED 2M RUC TEMPS AS FIRST GUESS FOR TEMPS RMNDR OF TNGT...WITH A FEW TWEEKS HERE AND THERE. THIS MAY NOT EVEN BE COLD ENOUGH...BUT WILL WATCH TEMPS FOR THE NXT FEW HRS TO SEE IF ADDITIONAL ADJUSTMENTS ARE NECESSARY. TRUETT && .DISCUSSION... SFC LOW HAS LIFTED NORTHEAST INTO OHIO THIS AFTERNOON. STILL HAVE SOME LINGERING FLURRIES OVER AREA AND TEMPS HAVE ONLY RISEN INTO THE MID TEENS TO LOW 20S. MAIN FORECAST ISSUES IN THE SHORT TERM ARE CLOUD COVER AND TEMPS. NEXT WEATHER SYSTEM TO MOVE INTO THE AREA THURSDAY NIGHT AND FRIDAY. FOR TONIGHT...CLOUDS TO SLOWLY BREAK UP FROM WEST TO EAST WITH SOME LINGERING FLURRIES FOR A FEW HOURS OVER FAR EASTERN SECTIONS OF CWA THIS EVENING. NORTHWEST WINDS WILL SLOWLY DIMINISH AND BACK TO THE WEST AND SOUTHWEST BY DAYBREAK. THIS WILL ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS IN THE NORTH TO LOW TO MID TEENS IN THE SOUTH HALF OF CWA. WEDNESDAY THROUGH THURSDAY WILL SEE A SLOW WARMING TREND AS RIDGE MOVES OFF TO OUR EAST...ALLOWING SOUTHERLY WINDS TO RETURN ONCE AGAIN. HIGHS ON WEDNESDAY WILL BE IN THE UPPER 20S TO UPPER 30S...LOWS WEDNESDAY NIGHT IN THE 20S AND HIGHS ON THURSDAY IN THE 40S. WILL SEE NEXT SYSTEM APPROACH THE AREA FROM THE NORTHWEST ON THURSDAY WITH THE FRONTAL BOUNDARY MOVING INTO NORTHWESTERN MO BY THURSDAY MORNING AND INTO THE ST. LOUIS AREA BY LATE AFTERNOON. PCPN WITH THIS SYSTEM WILL BE POST FRONTAL WITH A WIDE VARIETY OF PCPN TYPES. NORTHERN THIRD OF CWA WILL JUST SEE SNOW...WITH A MIX OF RAIN AND SNOW BRIEFLY ALONG I-70 CORRIDOR AND RAIN SOUTH...EARLY THURSDAY EVENING. COLDER AIR TO MAKE ITS WAY IN...BUT ICE CRYSTALS WILL BE LIMITED...SO COULD SEE SOME LIGHT FREEZING DRIZZLE MIXED WITH SOME SLEET OVER SOUTH HALF OF CWA FOR THE REST OF THURSDAY NIGHT. ACCUMULATION AMOUNTS WILL BE VERY LIGHT. ON FRIDAY...PCPN TO CHANGE OVER TO ALL SNOW EVERYWHERE WITH LITTLE OR NO ACCUMULATION EXPECTED. MAIN CONCERN AFTER THAT IS TIMING AND TRACK OF NEXT STORM SYSTEM. MODELS HAVE SLOWED DOWN THIS SYSTEM...KEEPING IT OVER THE SOUTHWESTERN US LONGER AND WHEN THEY DO LIFT IT OUT LATE SAT THROUGH SUNDAY...IT TRACKS WELL TO THE SOUTH OF THE AREA. SO JUST KEPT SILENT 20 POPS IN FAR SOUTHERN COUNTIES SATURDAY NIGHT AND SUNDAY. WILL HAVE TO KEEP AN EYE OUT ON THIS SYSTEM IN FUTURE MODEL RUNS. OTHERWISE...NO MAJOR CHANGES TO THE EXTENDED AT THIS TIME. BYRD && .AVIATION... FOR THE 00Z TAFS...MAIN FORECAST ISSUE IS CLEARING OF MVFR CIGS OUT OF THE TAF SITES. FAR BACKEDGE OF THIS CLOUD PUSHING THRU THE KUIN-KCOU AXIS NOW...BUT THIS IS THE MAIN STRATIFORM PORTION OF THE CLOUD DECK...WITH AREAS JUST TO THE W HAVING BECOME MORE CUMULIFORM AND STRIATED THIS AFTERNOON. GIVEN THAT...WILL KEEP CLOUDS IN TIL 02Z FOR KUIN AND KCOU...AND IN TIL 06Z FOR KSTL/KSUS BEFORE FINALLY CLEARING OUT. DID CONSIDER FOG TONIGHT...BUT SLEET/SNOW DEPTH NOT MUCH AT ALL AT THE TAF SITES...AND WINDS STAYING UP THRU THE NIGHT SHOULD PREVENT TEMPS EASILY ATTAINING DEWPOINT VALUES. WILL CONTINUE TO MONITOR. OTHERWISE...HI PRES RIDGE WILL MOVE THRU ON WEDNESDAY SWITCHING SFC WNDS AROUND TO THE S BY DAYS END. TES && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1144 PM CST MON FEB 11 2008 ...UPDATE TO AVIATION... .DISCUSSION... ROUND TWO OF OUR SIGNIFICANT ICE STORM IS NOW UNDERWAY. AT THE SURFACE...INVERTED TROUGH SIGNATURE EXTENDS FROM FAYETTEVILLE ARKANSAS TO JUST SOUTH OF VICHY. ISENTROPIC UPGLIDE IN THE 285-295K LAYER REMAINS QUITE STOUT COINCIDENT AND TO THE SOUTH OF THIS FEATURE. AS A RESULT...THERE IS A SHARP CUTOFF TO THE PRECIPITATION JUST TO THE NORTHWEST OF THE I-44 CORRIDOR. ALOFT...STRONG MID LEVEL DISTURBANCE CONTINUES TO PLOW SOUTHEASTWARD THROUGH THE UPPER MIDWEST. ELONGATED AREA OF VORTICITY AT 700MB LINES UP WELL THE BACK EDGE OF PRECIP. A 40 KT...AND STRENGTHENING...LOW LEVEL JET HAS BEEN OBSERVED VIA PROFILERS... THE 00Z KSGF RAOB AND RUC INITIALIZATIONS JUST OUT AHEAD OF THE RIBBON OF 700MB VORTICITY AND THE INVERTED TROUGH AT THE SURFACE. THE INCREASE IN WAA ALOFT HAS RESULTED IN RAPIDLY EXPANDING ECHOES ON THE LATEST WSR 88D IMAGERY. FOR THE EVENING HOURS...AREAS ALONG AND SOUTHEAST OF THE INTERSTATE 44 CORRIDOR WILL CONTINUE TO SEE AN INCREASE IN PRECIPITATION COVERAGE. THIS WILL MAINLY BE IN THE FORM OF FREEZING RAIN AND SLEET 4500FT WARM LAYER ALOFT VIA THE 00Z KSGF SOUNDING. HEAVIER SLEET ACCUMULATIONS WILL BE LIKELY AS 100 J/KG OF MUCAPE IS TAPPED. A SLOW SOUTHEASTWARD SHIFT TO THE PRECIPITATION SHIELD IS EXPECTED AS THE NIGHT PROGRESSES. IT APPEARS THAT AREAS ALONG AND SOUTHEAST OF A LINE FROM SALEM TO BRANSON WILL SEE PERIODS OF FREEZING RAIN AND SLEET AND HAVE EXTENDED THE WARNING THROUGH THE REST OF TONIGHT. WILL ALLOW THE WARNING IN AREAS JUST NORTHWEST OF THE INTERSTATE 44 CORRIDOR TO EXPIRE AT MIDNIGHT...MAYBE CANCELING EARLY BASED ON RADAR TRENDS. SUBSTANTIAL ICE ACCUMULATIONS ARE ON TAP FOR SOUTH CENTRAL MISSOURI. HAVE INCREASED EXPECTED AMOUNTS UP TO THREE QUARTERS OF AN INCH. HOWEVER...GIVEN CONVECTION...SCATTERED AMOUNTS UP TO ONE AND ONE HALF INCH WILL BE POSSIBLE FOR AREAS FROM SALEM TO SPARTA TO CASSVILLE AND POINTS SOUTHEASTWARD. AREAS JUST TO THE NORTHWEST OF THIS LIN...ALONG THE I44 CORRIDOR...WILL RECEIVE ANOTHER ONE QUARTER TO ONE HALF INCH OF ICE. ONCE AGAIN...AFFECTS OF CONVECTION WILL LEND TO AMOUNTS LOCALLY REACHING ONE INCH. THIS IS ALL ON TOP OF ICE ACCUMULATIONS THAT HAVE ALREADY TOPPED ONE INCH IN A FEW AREAS ALONG THE HIGHWAY 60 CORRIDOR. THE COMBINATION OF ICE ACCUMULATIONS AND WINDS INCREASING TO BETWEEN 10 AND 20 MPH WILL RESULT IN POWER OUTAGES TONIGHT. GAGAN && .AVIATION... FOR THE 0600 UTC KSGF/KJLN TAFS...EXPECT IFR CEILINGS TO CONTINUE THROUGH TONIGHT AND TUE MORNING. A SLOW IMPROVEMENT IN CEILINGS INTO THE MVFR CAT IS EXPECTED AS HIGH PRESSURE BEGINS TO BUILD INTO THE AREA LATE TUE AFTERNOON AND EVENING. MAY SEE SOME LIGHT FREEZING DRIZZLE...ESPECIALLY AT KSGF OVERNIGHT...AND WILL MONITOR TRENDS FOR THAT AND ITS IMPACT ON VISIBILITY. CLOUDS WILL LIKELY BEGIN TO SCATTER OUT OVER SOUTHEAST KANSAS/EXTREME WESTERN MO BY EARLY EVENING. DSA && .SGF WATCHES/WARNINGS/ADVISORIES... MO...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MOZ070-071- 081>083-090>098-101>106. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MOZ057-058- 069-079-080-088-089. KS...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR KSZ101. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 724 PM CST MON FEB 11 2008 .DISCUSSION... ROUND TWO OF OUR SIGNIFICANT ICE STORM IS NOW UNDERWAY. AT THE SURFACE...INVERTED TROUGH SIGNATURE EXTENDS FROM FAYETTEVILLE ARKANSAS TO JUST SOUTH OF VICHY. ISENTROPIC UPGLIDE IN THE 285-295K LAYER REMAINS QUITE STOUT COINCIDENT AND TO THE SOUTH OF THIS FEATURE. AS A RESULT...THERE IS A SHARP CUTOFF TO THE PRECIPITATION JUST TO THE NORTHWEST OF THE I-44 CORRIDOR. ALOFT...STRONG MID LEVEL DISTURBANCE CONTINUES TO PLOW SOUTHEASTWARD THROUGH THE UPPER MIDWEST. ELONGATED AREA OF VORTICITY AT 700MB LINES UP WELL THE BACK EDGE OF PRECIP. A 40 KT...AND STRENGTHENING...LOW LEVEL JET HAS BEEN OBSERVED VIA PROFILERS... THE 00Z KSGF RAOB AND RUC INITIALIZATIONS JUST OUT AHEAD OF THE RIBBON OF 700MB VORTICITY AND THE INVERTED TROUGH AT THE SURFACE. THE INCREASE IN WAA ALOFT HAS RESULTED IN RAPIDLY EXPANDING ECHOES ON THE LATEST WSR 88D IMAGERY. FOR THE EVENING HOURS...AREAS ALONG AND SOUTHEAST OF THE INTERSTATE 44 CORRIDOR WILL CONTINUE TO SEE AN INCREASE IN PRECIPITATION COVERAGE. THIS WILL MAINLY BE IN THE FORM OF FREEZING RAIN AND SLEET 4500FT WARM LAYER ALOFT VIA THE 00Z KSGF SOUNDING. HEAVIER SLEET ACCUMULATIONS WILL BE LIKELY AS 100 J/KG OF MUCAPE IS TAPPED. A SLOW SOUTHEASTWARD SHIFT TO THE PRECIPITATION SHIELD IS EXPECTED AS THE NIGHT PROGRESSES. IT APPEARS THAT AREAS ALONG AND SOUTHEAST OF A LINE FROM SALEM TO BRANSON WILL SEE PERIODS OF FREEZING RAIN AND SLEET AND HAVE EXTENDED THE WARNING THROUGH THE REST OF TONIGHT. WILL ALLOW THE WARNING IN AREAS JUST NORTHWEST OF THE INTERSTATE 44 CORRIDOR TO EXPIRE AT MIDNIGHT...MAYBE CANCELING EARLY BASED ON RADAR TRENDS. SUBSTANTIAL ICE ACCUMULATIONS ARE ON TAP FOR SOUTH CENTRAL MISSOURI. HAVE INCREASED EXPECTED AMOUNTS UP TO THREE QUARTERS OF AN INCH. HOWEVER...GIVEN CONVECTION...SCATTERED AMOUNTS UP TO ONE AND ONE HALF INCH WILL BE POSSIBLE FOR AREAS FROM SALEM TO SPARTA TO CASSVILLE AND POINTS SOUTHEASTWARD. AREAS JUST TO THE NORTHWEST OF THIS LIN...ALONG THE I44 CORRIDOR...WILL RECEIVE ANOTHER ONE QUARTER TO ONE HALF INCH OF ICE. ONCE AGAIN...AFFECTS OF CONVECTION WILL LEND TO AMOUNTS LOCALLY REACHING ONE INCH. THIS IS ALL ON TOP OF ICE ACCUMULATIONS THAT HAVE ALREADY TOPPED ONE INCH IN A FEW AREAS ALONG THE HIGHWAY 60 CORRIDOR. THE COMBINATION OF ICE ACCUMULATIONS AND WINDS INCREASING TO BETWEEN 10 AND 20 MPH WILL RESULT IN POWER OUTAGES TONIGHT. GAGAN && .AVIATION... FOR THE 00Z TAF PACKAGE...FZRA AND AND FZDZ ARE EXPECTED TO CONTINUE AT BOTH KJLN AND KSGF THROUGH 09Z WITH LIFR CEILINGS. WHILE THE PRECIPITATION ENDS...PREDOMINATELY IFR CEILINGS ARE EXPECTED AT KJLN FROM 11Z TO 18Z AND KSGF FROM 11Z TO 20Z. CEILINGS WILL CONTINUE TO RISE TUESDAY AFTERNOON AS SURFACE HIGH PRESSURE BUILDS SOUTH INTO THE OZARKS. VFR CONDITIONS ARE EXPECTED AROUND 22Z. ANGLE && .PREV DISCUSSION... /ISSUED 556 PM CST MON FEB 11 2008/ ..WINTER STORM CONTINUES... SHORT TERM (TONIGHT)... VERY COMPLICATED FORECAST DURING THE NEXT 12-18 HOURS AS MESOSCALE PROCESSES AID IN THE DEVELOPMENT OF MORE FREEZING RAIN AND SLEET ACROSS MAINLY EXTREME SOUTHERN MISSOURI. MORNING FREEZING RAIN...SLEET AND SNOW ACCUMULATIONS WERE QUITE SIGNIFICANT AS INSTABILITY ALOFT COMBINED WITH BELOW FREEZING TEMPERATURES NEAR THE SURFACE TO CREATE AREAS OF CONVECTION AND LOCALLY HEAVY PRECIPITATION. THE MOST SIGNIFICANT AMOUNTS WERE ALONG THE HIGHWAY 60 CORRIDOR FROM JOPLIN TO MONETT...SPRINGFIELD AND SEYMOUR. LOCALLY ONE HALF TO ONE INCH OF ICE ACCUMULATED ON TREES AND POWER LINES. FURTHER EAST MORE SLEET FELL AND AREAS TO THE NORTH OF I-44 HAD A MIXTURE OF SLEET AND FREEZING RAIN. REGIONAL RADAR HAS BEEN SHOWING SOME RETURNS IN NORTHEASTERN OKLAHOMA WHICH MAY BE INFLUENCED BY MID LEVEL FRONTOGENESIS OR AN INCREASE IN LARGE SCALE LIFT WITH THE NEXT WAVE MOVING SOUTHEAST ACROSS NEBRASKA AND KANSAS. SOME MESOSCALE INFLUENCES INDICATE MORE OF THE DEEP MOISTURE WILL RESIDE IN EXTREME SOUTHERN MISSOURI...AND MAINLY AFFECT COMMUNITIES EAST OF CASSVILLE AND BRANSON. SINCE THE REGION HAS ALREADY HAD A SIGNIFICANT AMOUNT OF ICE ACCUMULATIONS...AND BOTH THE WRF/GFS HAVE SOME MINOR DIFFERENCE ALONG THE I-44 CORRIDOR...HAVE OPTED TO ERROR ON THE WETTER AND MORE CRITICAL SCENARIO WITH ANOTHER AROUND OF ONE QUARTER...TO LOCALLY THREE QUARTERS OF AN INCH OF FREEZING RAIN AND SLEET FOR AREAS MAINLY ALONG AND SOUTH OF HIGHWAY 60 AND EAST OF HIGHWAY 71. THE MOST CRITICAL TIME FOR THE HEAVIEST PRECIPITATION WILL BE BETWEEN 6 PM AND MIDNIGHT. ANOTHER PROBLEM DEALS WITH SURFACE TEMPERATURES AS THE FREEZING MARK IS HOLDING NEAR THE MISSOURI-ARKANSAS BORDER. SHORT TERM MODELS CONTINUE TO HAVE TEMPERATURES ALONG THE MISSOURI-ARKANSAS BORDER RISING TO ABOVE FREEZING DURING THE EVENING HOURS...HOWEVER SINCE TEMPERATURES HAVE NOT RISEN TOO MUCH SINCE NOON...AND THE LOSS OF DAYTIME HEATING OCCURS...BELIEVE ANY TEMPERATURES THAT AREA ABOVE FREEZING WILL LIKELY HOLD OR FALL A COUPLE OF DEGREES. THERE IS ANOTHER SCENARIO IF A SURFACE WAVE DEVELOPS AND ALLOWS FOR TEMPERATURES TO SURGE NORTHWARD ACROSS THE BORDER. THE LATER SHIFTS WILL NEED TO DETERMINE THE AMOUNT OF WARM AIR ADVECTION AND IF TEMPERATURES BEGIN TO RISE SIGNIFICANTLY. AFTER MIDNIGHT...THE MAIN UPPER WAVE SHOULD BE ALONG THE I-44 CORRIDOR WITH MOST OF THE PRECIPITATION EXITING THE REGION BY SUNRISE. JLT LONG TERM (TUESDAY THROUGH MONDAY)... COLD FRONT WILL BE SOUTHEAST OF THE FORECAST AREA TUESDAY MORNING WITH WINTER PRECIPITATION TAPERING OFF ACROSS SOUTH CENTRAL MISSOURI. SURFACE HIGH PRESSURE WILL BUILD SOUTH ACROSS THE OZARKS TUESDAY NIGHT. HAVE UNDERCUT MAV/MET GUIDANCE FOR HIGHS AND LOWS DUE TO ICE ACCUMULATION AND GOOD RADIATIONAL COOLING SETUP. FOG POTENTIAL WILL NEED TO BE MONITORED TUESDAY NIGHT INTO WEDNESDAY MORNING. AS SURFACE HIGH PRESSURE BUILDS EAST AND LEESIDE TROUGH DEVELOPS...THE PRESSURE GRADIENT WILL TIGHTEN ACROSS THE REGION. TEMPERATURES WILL REBOUND WITH SOUTH WINDS INCREASING WEDNESDAY AND THURSDAY AS GULF MOISTURE SURGES NORTH. SURFACE COLD FRONT WILL MOVE INTO THE OZARKS THURSDAY NIGHT WITH CHANCES FOR RAIN AHEAD OF THE FRONT AND WINTER PRECIPITATION AGAIN POSSIBLE BEHIND THE FRONT. WINTER PRECIPITATION CHANCES WILL CONTINUE INTO THE WEEKEND AS BOTH THE GFS AND ECMWF DEPICT SIMILAR SOLUTIONS OF A DEEPENING CUTOFF LOW DIGGING INTO THE BOOT HEEL OF TEXAS. THE PRECIPITATION TYPE AND AMOUNTS WILL DEPEND UPON THE TRACK OF THIS UPPER LEVEL LOW AS IT MOVES TOWARD THE LOWER MISSISSIPPI VALLEY. HOWEVER...AT THIS TIME IT LOOKS LIKE THE MISSOURI OZARKS WILL BE DEALING WITH MORE WINTER WEATHER OVER THE WEEKEND. THE FORECAST WILL BE FINED TUNED FURTHER WITH FUTURE MODEL RUNS. ANGLE && .SGF WATCHES/WARNINGS/ADVISORIES... MO...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MOZ070-071- 081>083-090>098-101>106. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MOZ057-058- 068-069-077>080-088-089. KS...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR KSZ097-101. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1156 AM MST MON FEB 11 2008 .UPDATE... QUICK UPDATE DONE TO REFLECT TRENDS IN CURRENT TEMPS AND CLOUD COVERAGE. TEMPERATURES AT MANY LOCATIONS...ESPECIALLY OVER THE PLAINS...HAVE WARMED CONSIDERABLY IN RESPONSE TO GOOD DOWNSLOPING WITH SOUTHWESTERLY SURFACE WINDS...AND HIGH TEMPS TODAY WERE INCREASED AROUND CENTRAL MONTANA. CLOUD COVERAGE WAS ALSO REDUCED IN THE FORECAST FOR TODAY. COHEN && .PREV DISCUSSION... (ISSUED 1040 AM MST MON FEB 11 2008) SHORTWAVE TROUGH THAT BROUGHT SNOW SHOWERS TO THE REGION CONTINUES DIVING SOUTHEAST OF THE REGION...WITH BEST SYNOPTIC ASCENT AND DEEP MOISTURE NOW OVER THE DAKOTAS. AREA OF WEAK INSTABILITY ON THE BACK SIDE OF THE TROUGH HAS BEEN MAINTAINING SCATTERED SNOW SHOWERS OVER EASTERN CWA...WHICH WILL CONTINUE TO TAPER OFF THROUGH THE DAY AS MID LEVEL WARM AIR ADVECTION COMMENCES DUE TO BUILDING MID/UPPER LEVEL RIDGE. THE SNOW AND BLOWING SNOW ADVISORY IS BEING CANCELLED WITH THE ISSUANCE OF THE MORNING UPDATE PACKAGE...WITH RUC GUIDANCE SHOWS ANY ADDITIONAL SNOWFALL ACCUMULATIONS VERY LIGHT AND RESTRICTED TO THE SOUTHWEST MOUNTAINS...ALONG WITH DIMINISHING SURFACE WINDS TO UNDER 10 KTS PRECLUDING BLOWING SNOW THREAT. OTHERWISE...SUBSIDENCE DOWNSTREAM OF BUILDING RIDGE WILL HELP TEMPERATURES WARM AGAIN TODAY...AS SURFACE LEE TROUGHING OCCURS OVER CENTRAL AND EASTERN MONTANA AND SURFACE WINDS BACK TO THE WEST SOUTHWEST. HIGH TEMPERATURES OVER THE PLAINS WERE INCREASED A BIT TO ACCOUNT FOR THIS. ALSO...WIND AND CLOUD COVERAGE WERE TWEAKED A BIT TO ACCOUNT FOR CURRENT CONDITIONS. MODIFIED ARCTIC AIRMASS OVER FAR NORTHEAST CWA IS EXPECTED TO RETREAT NORTHEAST OF HAVRE TODAY...AS LEE TROUGHING AFFECTS THE REGION...WITH SURFACE PRESSURE FALLS OVER THE EASTERN TWO THIRDS OF MONTANA. LOOKING FURTHER AHEAD...NEXT MAJOR CONCERN WILL BE SYSTEM MOVING INTO THE PACIFIC NORTHWEST MID-WEEK...WITH STRONG WINDS AND SNOW BOTH POSSIBLE OVER THE WESTERN MOUNTAINS. HIGHLIGHTS MAY BECOME NECESSARY BY THIS AFTERNOON. COHEN PREV DISCUSSION... (ISSUED 435 AM MST MON FEB 11 2008) TODAY THROUGH WEDNESDAY...THE REMNANTS OF AN UPPER LEVEL STORM SYSTEM WILL REMAIN OVER THE SOUTHWEST MOUNTAINS AND EASTERN PLAINS THROUGH THE EARLY AFTERNOON HOURS. ALSO...THE REMAINING ARCTIC AIR WILL LIKELY STAY IN PLACE OVER THE FAR NORTHEASTERN CORNER OF THE FORECAST AREA THROUGH AT LEAST WEDNESDAY. ELSEWHERE...WEST AND SOUTHWESTERLY BREEZES EAST OF THE CONTINENTAL DIVIDE WILL ALLOW TEMPERATURES TO REMAIN QUITE MILD THROUGH TUESDAY. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REACH THE REGION BY TUESDAY...WITH MOSTLY DRY CONDITIONS BETWEEN THIS AFTERNOON THROUGH TUESDAY AFTERNOON. ANOTHER FAST MOVING UPPER LEVEL STORM SYSTEM WILL AFFECT THE AREA BY TUESDAY EVENING...WITH WIDESPREAD SNOW POTENTIAL FOR BOTH THE PLAINS AND MOUNTAIN RANGES. FOR WEDNESDAY...MODELS ARE SUGGESTING A COUPLE OF INCHES OF SNOW ACCUMULATION ACROSS THE PLAINS...WITH THE SURFACE LOW PRESSURE CENTER TRACKING OVER NORTHEAST MONTANA. THIS SCENARIO WILL LIKELY ALLOW SOME COLDER AIR FROM ALBERTA TO SEEP BACK INTO THE HILINE REGION...HOWEVER THE COLD AIR DOES NOT APPEAR TO SPREAD THROUGH THE ENTIRE NORTH CENTRAL PLAINS. UNSTABLE NORTHWESTERLY FLOW AT THE MIDLEVELS DURING WEDNESDAY DOES FAVOR DECENT SNOW ACCUMULATIONS FOR THE CENTRAL AND SOUTHWEST MOUNTAINS...HOWEVER THE MAIN FORCING ASSOCIATED WITH THIS STORM SYSTEM APPEARS TO MOVE VERY QUICKLY. CONSEQUENTLY...NO WINTER WEATHER HIGHLIGHTS ARE PLANNED AT THIS TIME. ZUMPFE WEDNESDAY NIGHT THROUGH SATURDAY NIGHT...PERIOD STARTS OUT WITH AN UPPER LEVEL TROUGH EXITING THE REGION. SNOW SHOWERS WILL LINGER OVER MUCH OF MY CWA WEDNESDAY EVENING BUT WILL DISSIPATE QUICKLY AS AN UPPER LEVEL RIDGE BUILDS INTO WESTERN MONTANA ON THURSDAY. WESTERLY SURFACE WINDS WILL PREVAIL ACROSS MY FORECAST AREA THROUGH FRIDAY NIGHT FOR MOSTLY DRY CONDITIONS OVER THE PLAINS WHILE THE WESTERN MOUNTAINS WILL CONTINUE TO SEE A CHANCE OF SNOW. TEMPERATURES WILL WARM ABOVE SEASONAL AVERAGES WITH THE UPPER RIDGE NOSING OVER THE NORTHERN ROCKY MOUNTAINS LATE IN THE WEEK. MODELS IN PRETTY GOOD AGREEMENT BRINGING ANOTHER SHORTWAVE TROUGH THROUGH THE REGION ON SATURDAY. PATTERN LOOKS FAVORABLE FOR A SHIFT TO NORTHERLY WINDS AND AN INCREASED CHANCE OF MOUNTAIN SNOW SHOWERS AS A COLD FRONT PUSHES SOUTH OUT OF CANADA. HOWEVER...MODEL GUIDANCE IS NOT SHOWING A VERY PRONOUNCED COOL DOWN. EASTERN PORTIONS OF MY CWA ARE MOST LIKELY TO SEE COOLER TEMPERATURES...BUT EVEN HERE THE COOLER AIR WILL BE SHORT-LIVED AS THE AIRMASS SLIDES EAST BY SUNDAY. MPJ SUNDAY THROUGH MONDAY...MODELS ARE IN BASIC AGREEMENT DURING THIS PERIOD...WITH ONLY MINOR DIFFERENCES IN TIMING AND AMPLITUDE OF THE UPPER LEVEL RIDGE MOVING OVER THE PACIFIC NORTHWEST. I LEANED TOWARD THE GFS SOLUTION OF A LOWER AMPLITUDE RIDGE THAT IS MORE PROGRESSIVE THAN THE ECMWF. A WEAK COLD FRONT MOVES EAST OF THE FORECAST AREA EARLY SUNDAY. A FEW SNOW SHOWERS ARE EXPECTED IN THE EAST SUNDAY MORNING...OTHERWISE MOST AREAS ARE PARTLY TO MOSTLY CLOUDY AND DRY. HOWEVER...THERE IS SUFFICIENT MOISTURE IN A NORTHWESTERLY FLOW ALOFT FOR A SLIGHT CHANCE OF SNOW OVER THE CENTRAL...WESTERN AND SOUTHWESTERN MOUNTAINS. GUSTY DOWNSLOPE WINDS ARE EXPECTED ALONG THE FRONT RANGE OF THE ROCKIES AND ADJACENT PLAINS. TEMPERATURES COOL SEVERAL DEGREES SUNDAY BEFORE RETURNING TO NEAR SEASONAL AVERAGES MONDAY. EK AVIATION... UPDATED 1740Z. MOIST NORTHWEST FLOW ALOFT WILL CONTINUE. CLOUDS WILL BEGIN TO DECREASE AS HIGH PRESSURE ALOFT BEGINS TO BUILD OVER WESTERN MONTANA. VFR CONDITIONS PREVAIL EXCEPT IN THE VICINITY OF KHVR WHERE THE COLD FRONTAL BOUNDARY PERSISTS. MVFR CONDITIONS DUE TO LOW CEILINGS AND LIGHT SNOW WILL CONTINUE IN THE KHVR AREA UNTIL 22Z. && .PRELIMINARY POINT TEMPS/POPS... GTF 43 25 44 24 / 10 0 20 30 CTB 42 23 39 20 / 10 10 10 30 HLN 43 24 40 22 / 20 20 30 40 BZN 42 20 39 21 / 40 20 30 50 WEY 34 12 31 16 / 50 50 40 80 DLN 41 22 41 20 / 20 10 20 60 HVR 26 14 37 17 / 30 0 20 30 LWT 42 21 40 22 / 30 0 20 30 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...COHEN SHORT TERM...ZUMPFE LONG TERM...MPJ/EK AVIATION...EMANUEL WEATHER.GOV/GREATFALLS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1040 AM MST MON FEB 11 2008 UPDATED AVIATION SECTION .DISCUSSION... SHORTWAVE TROUGH THAT BROUGHT SNOW SHOWERS TO THE REGION CONTINUES DIVING SOUTHEAST OF THE REGION...WITH BEST SYNOPTIC ASCENT AND DEEP MOISTURE NOW OVER THE DAKOTAS. AREA OF WEAK INSTABILITY ON THE BACK SIDE OF THE TROUGH HAS BEEN MAINTAINING SCATTERED SNOW SHOWERS OVER EASTERN CWA...WHICH WILL CONTINUE TO TAPER OFF THROUGH THE DAY AS MID LEVEL WARM AIR ADVECTION COMMENCES DUE TO BUILDING MID/UPPER LEVEL RIDGE. THE SNOW AND BLOWING SNOW ADVISORY IS BEING CANCELLED WITH THE ISSUANCE OF THE MORNING UPDATE PACKAGE...WITH RUC GUIDANCE SHOWS ANY ADDITIONAL SNOWFALL ACCUMULATIONS VERY LIGHT AND RESTRICTED TO THE SOUTHWEST MOUNTAINS...ALONG WITH DIMINISHING SURFACE WINDS TO UNDER 10 KTS PRECLUDING BLOWING SNOW THREAT. OTHERWISE...SUBSIDENCE DOWNSTREAM OF BUILDING RIDGE WILL HELP TEMPERATURES WARM AGAIN TODAY...AS SURFACE LEE TROUGHING OCCURS OVER CENTRAL AND EASTERN MONTANA AND SURFACE WINDS BACK TO THE WEST SOUTHWEST. HIGH TEMPERATURES OVER THE PLAINS WERE INCREASED A BIT TO ACCOUNT FOR THIS. ALSO...WIND AND CLOUD COVERAGE WERE TWEAKED A BIT TO ACCOUNT FOR CURRENT CONDITIONS. MODIFIED ARCTIC AIRMASS OVER FAR NORTHEAST CWA IS EXPECTED TO RETREAT NORTHEAST OF HAVRE TODAY...AS LEE TROUGHING AFFECTS THE REGION...WITH SURFACE PRESSURE FALLS OVER THE EASTERN TWO THIRDS OF MONTANA. LOOKING FURTHER AHEAD...NEXT MAJOR CONCERN WILL BE SYSTEM MOVING INTO THE PACIFIC NORTHWEST MID-WEEK...WITH STRONG WINDS AND SNOW BOTH POSSIBLE OVER THE WESTERN MOUNTAINS. HIGHLIGHTS MAY BECOME NECESSARY BY THIS AFTERNOON. COHEN && .PREV DISCUSSION... (ISSUED 435 AM MST MON FEB 11 2008) TODAY THROUGH WEDNESDAY...THE REMNANTS OF AN UPPER LEVEL STORM SYSTEM WILL REMAIN OVER THE SOUTHWEST MOUNTAINS AND EASTERN PLAINS THROUGH THE EARLY AFTERNOON HOURS. ALSO...THE REMAINING ARCTIC AIR WILL LIKELY STAY IN PLACE OVER THE FAR NORTHEASTERN CORNER OF THE FORECAST AREA THROUGH AT LEAST WEDNESDAY. ELSEWHERE...WEST AND SOUTHWESTERLY BREEZES EAST OF THE CONTINENTAL DIVIDE WILL ALLOW TEMPERATURES TO REMAIN QUITE MILD THROUGH TUESDAY. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REACH THE REGION BY TUESDAY...WITH MOSTLY DRY CONDITIONS BETWEEN THIS AFTERNOON THROUGH TUESDAY AFTERNOON. ANOTHER FAST MOVING UPPER LEVEL STORM SYSTEM WILL AFFECT THE AREA BY TUESDAY EVENING...WITH WIDESPREAD SNOW POTENTIAL FOR BOTH THE PLAINS AND MOUNTAIN RANGES. FOR WEDNESDAY...MODELS ARE SUGGESTING A COUPLE OF INCHES OF SNOW ACCUMULATION ACROSS THE PLAINS...WITH THE SURFACE LOW PRESSURE CENTER TRACKING OVER NORTHEAST MONTANA. THIS SCENARIO WILL LIKELY ALLOW SOME COLDER AIR FROM ALBERTA TO SEEP BACK INTO THE HILINE REGION...HOWEVER THE COLD AIR DOES NOT APPEAR TO SPREAD THROUGH THE ENTIRE NORTH CENTRAL PLAINS. UNSTABLE NORTHWESTERLY FLOW AT THE MIDLEVELS DURING WEDNESDAY DOES FAVOR DECENT SNOW ACCUMULATIONS FOR THE CENTRAL AND SOUTHWEST MOUNTAINS...HOWEVER THE MAIN FORCING ASSOCIATED WITH THIS STORM SYSTEM APPEARS TO MOVE VERY QUICKLY. CONSEQUENTLY...NO WINTER WEATHER HIGHLIGHTS ARE PLANNED AT THIS TIME. ZUMPFE WEDNESDAY NIGHT THROUGH SATURDAY NIGHT...PERIOD STARTS OUT WITH AN UPPER LEVEL TROUGH EXITING THE REGION. SNOW SHOWERS WILL LINGER OVER MUCH OF MY CWA WEDNESDAY EVENING BUT WILL DISSIPATE QUICKLY AS AN UPPER LEVEL RIDGE BUILDS INTO WESTERN MONTANA ON THURSDAY. WESTERLY SURFACE WINDS WILL PREVAIL ACROSS MY FORECAST AREA THROUGH FRIDAY NIGHT FOR MOSTLY DRY CONDITIONS OVER THE PLAINS WHILE THE WESTERN MOUNTAINS WILL CONTINUE TO SEE A CHANCE OF SNOW. TEMPERATURES WILL WARM ABOVE SEASONAL AVERAGES WITH THE UPPER RIDGE NOSING OVER THE NORTHERN ROCKY MOUNTAINS LATE IN THE WEEK. MODELS IN PRETTY GOOD AGREEMENT BRINGING ANOTHER SHORTWAVE TROUGH THROUGH THE REGION ON SATURDAY. PATTERN LOOKS FAVORABLE FOR A SHIFT TO NORTHERLY WINDS AND AN INCREASED CHANCE OF MOUNTAIN SNOW SHOWERS AS A COLD FRONT PUSHES SOUTH OUT OF CANADA. HOWEVER...MODEL GUIDANCE IS NOT SHOWING A VERY PRONOUNCED COOL DOWN. EASTERN PORTIONS OF MY CWA ARE MOST LIKELY TO SEE COOLER TEMPERATURES...BUT EVEN HERE THE COOLER AIR WILL BE SHORT-LIVED AS THE AIRMASS SLIDES EAST BY SUNDAY. MPJ SUNDAY THROUGH MONDAY...MODELS ARE IN BASIC AGREEMENT DURING THIS PERIOD...WITH ONLY MINOR DIFFERENCES IN TIMING AND AMPLITUDE OF THE UPPER LEVEL RIDGE MOVING OVER THE PACIFIC NORTHWEST. I LEANED TOWARD THE GFS SOLUTION OF A LOWER AMPLITUDE RIDGE THAT IS MORE PROGRESSIVE THAN THE ECMWF. A WEAK COLD FRONT MOVES EAST OF THE FORECAST AREA EARLY SUNDAY. A FEW SNOW SHOWERS ARE EXPECTED IN THE EAST SUNDAY MORNING...OTHERWISE MOST AREAS ARE PARTLY TO MOSTLY CLOUDY AND DRY. HOWEVER...THERE IS SUFFICIENT MOISTURE IN A NORTHWESTERLY FLOW ALOFT FOR A SLIGHT CHANCE OF SNOW OVER THE CENTRAL...WESTERN AND SOUTHWESTERN MOUNTAINS. GUSTY DOWNSLOPE WINDS ARE EXPECTED ALONG THE FRONT RANGE OF THE ROCKIES AND ADJACENT PLAINS. TEMPERATURES COOL SEVERAL DEGREES SUNDAY BEFORE RETURNING TO NEAR SEASONAL AVERAGES MONDAY. EK && .AVIATION... UPDATED 1740Z. MOIST NORTHWEST FLOW ALOFT WILL CONTINUE. CLOUDS WILL BEGIN TO DECREASE AS HIGH PRESSURE ALOFT BEGINS TO BUILD OVER WESTERN MONTANA. VFR CONDITIONS PREVAIL EXCEPT IN THE VICINITY OF KHVR WHERE THE COLD FRONTAL BOUNDARY PERSISTS. MVFR CONDITIONS DUE TO LOW CEILINGS AND LIGHT SNOW WILL CONTINUE IN THE KHVR AREA UNTIL 22Z. && .PRELIMINARY POINT TEMPS/POPS... GTF 39 25 44 24 / 10 0 10 30 CTB 38 23 39 20 / 10 10 10 30 HLN 42 24 40 22 / 20 20 20 40 BZN 42 20 39 21 / 40 10 30 50 WEY 30 12 31 16 / 50 30 30 60 DLN 40 22 41 20 / 20 20 20 50 HVR 28 14 37 17 / 30 0 10 30 LWT 35 21 40 22 / 30 0 10 30 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...COHEN SHORT TERM...ZUMPFE LONG TERM...MPJ/EK AVIATION...EMANUEL WEATHER.GOV/GREATFALLS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 920 AM MST MON FEB 11 2008 .UPDATE... SHORTWAVE TROUGH THAT BROUGHT SNOW SHOWERS TO THE REGION CONTINUES DIVING SOUTHEAST OF THE REGION...WITH BEST SYNOPTIC ASCENT AND DEEP MOISTURE NOW OVER THE DAKOTAS. AREA OF WEAK INSTABILITY ON THE BACK SIDE OF THE TROUGH HAS BEEN MAINTAINING SCATTERED SNOW SHOWERS OVER EASTERN CWA...WHICH WILL CONTINUE TO TAPER OFF THROUGH THE DAY AS MID LEVEL WARM AIR ADVECTION COMMENCES DUE TO BUILDING MID/UPPER LEVEL RIDGE. THE SNOW AND BLOWING SNOW ADVISORY IS BEING CANCELLED WITH THE ISSUANCE OF THE MORNING UPDATE PACKAGE...WITH RUC GUIDANCE SHOWS ANY ADDITIONAL SNOWFALL ACCUMULATIONS VERY LIGHT AND RESTRICTED TO THE SOUTHWEST MOUNTAINS...ALONG WITH DIMINISHING SURFACE WINDS TO UNDER 10 KTS PRECLUDING BLOWING SNOW THREAT. OTHERWISE...SUBSIDENCE DOWNSTREAM OF BUILDING RIDGE WILL HELP TEMPERATURES WARM AGAIN TODAY...AS SURFACE LEE TROUGHING OCCURS OVER CENTRAL AND EASTERN MONTANA AND SURFACE WINDS BACK TO THE WEST SOUTHWEST. HIGH TEMPERATURES OVER THE PLAINS WERE INCREASED A BIT TO ACCOUNT FOR THIS. ALSO...WIND AND CLOUD COVERAGE WERE TWEAKED A BIT TO ACCOUNT FOR CURRENT CONDITIONS. MODIFIED ARCTIC AIRMASS OVER FAR NORTHEAST CWA IS EXPECTED TO RETREAT NORTHEAST OF HAVRE TODAY...AS LEE TROUGHING AFFECTS THE REGION...WITH SURFACE PRESSURE FALLS OVER THE EASTERN TWO THIRDS OF MONTANA. LOOKING FURTHER AHEAD...NEXT MAJOR CONCERN WILL BE SYSTEM MOVING INTO THE PACIFIC NORTHWEST MID-WEEK...WITH STRONG WINDS AND SNOW BOTH POSSIBLE OVER THE WESTERN MOUNTAINS. HIGHLIGHTS MAY BECOME NECESSARY BY THIS AFTERNOON. COHEN && .PREV DISCUSSION... (ISSUED 435 AM MST MON FEB 11 2008) TODAY THROUGH WEDNESDAY...THE REMNANTS OF AN UPPER LEVEL STORM SYSTEM WILL REMAIN OVER THE SOUTHWEST MOUNTAINS AND EASTERN PLAINS THROUGH THE EARLY AFTERNOON HOURS. ALSO...THE REMAINING ARCTIC AIR WILL LIKELY STAY IN PLACE OVER THE FAR NORTHEASTERN CORNER OF THE FORECAST AREA THROUGH AT LEAST WEDNESDAY. ELSEWHERE...WEST AND SOUTHWESTERLY BREEZES EAST OF THE CONTINENTAL DIVIDE WILL ALLOW TEMPERATURES TO REMAIN QUITE MILD THROUGH TUESDAY. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REACH THE REGION BY TUESDAY...WITH MOSTLY DRY CONDITIONS BETWEEN THIS AFTERNOON THROUGH TUESDAY AFTERNOON. ANOTHER FAST MOVING UPPER LEVEL STORM SYSTEM WILL AFFECT THE AREA BY TUESDAY EVENING...WITH WIDESPREAD SNOW POTENTIAL FOR BOTH THE PLAINS AND MOUNTAIN RANGES. FOR WEDNESDAY...MODELS ARE SUGGESTING A COUPLE OF INCHES OF SNOW ACCUMULATION ACROSS THE PLAINS...WITH THE SURFACE LOW PRESSURE CENTER TRACKING OVER NORTHEAST MONTANA. THIS SCENARIO WILL LIKELY ALLOW SOME COLDER AIR FROM ALBERTA TO SEEP BACK INTO THE HILINE REGION...HOWEVER THE COLD AIR DOES NOT APPEAR TO SPREAD THROUGH THE ENTIRE NORTH CENTRAL PLAINS. UNSTABLE NORTHWESTERLY FLOW AT THE MIDLEVELS DURING WEDNESDAY DOES FAVOR DECENT SNOW ACCUMULATIONS FOR THE CENTRAL AND SOUTHWEST MOUNTAINS...HOWEVER THE MAIN FORCING ASSOCIATED WITH THIS STORM SYSTEM APPEARS TO MOVE VERY QUICKLY. CONSEQUENTLY...NO WINTER WEATHER HIGHLIGHTS ARE PLANNED AT THIS TIME. ZUMPFE WEDNESDAY NIGHT THROUGH SATURDAY NIGHT...PERIOD STARTS OUT WITH AN UPPER LEVEL TROUGH EXITING THE REGION. SNOW SHOWERS WILL LINGER OVER MUCH OF MY CWA WEDNESDAY EVENING BUT WILL DISSIPATE QUICKLY AS AN UPPER LEVEL RIDGE BUILDS INTO WESTERN MONTANA ON THURSDAY. WESTERLY SURFACE WINDS WILL PREVAIL ACROSS MY FORECAST AREA THROUGH FRIDAY NIGHT FOR MOSTLY DRY CONDITIONS OVER THE PLAINS WHILE THE WESTERN MOUNTAINS WILL CONTINUE TO SEE A CHANCE OF SNOW. TEMPERATURES WILL WARM ABOVE SEASONAL AVERAGES WITH THE UPPER RIDGE NOSING OVER THE NORTHERN ROCKY MOUNTAINS LATE IN THE WEEK. MODELS IN PRETTY GOOD AGREEMENT BRINGING ANOTHER SHORTWAVE TROUGH THROUGH THE REGION ON SATURDAY. PATTERN LOOKS FAVORABLE FOR A SHIFT TO NORTHERLY WINDS AND AN INCREASED CHANCE OF MOUNTAIN SNOW SHOWERS AS A COLD FRONT PUSHES SOUTH OUT OF CANADA. HOWEVER...MODEL GUIDANCE IS NOT SHOWING A VERY PRONOUNCED COOL DOWN. EASTERN PORTIONS OF MY CWA ARE MOST LIKELY TO SEE COOLER TEMPERATURES...BUT EVEN HERE THE COOLER AIR WILL BE SHORT-LIVED AS THE AIRMASS SLIDES EAST BY SUNDAY. MPJ SUNDAY THROUGH MONDAY...MODELS ARE IN BASIC AGREEMENT DURING THIS PERIOD...WITH ONLY MINOR DIFFERENCES IN TIMING AND AMPLITUDE OF THE UPPER LEVEL RIDGE MOVING OVER THE PACIFIC NORTHWEST. I LEANED TOWARD THE GFS SOLUTION OF A LOWER AMPLITUDE RIDGE THAT IS MORE PROGRESSIVE THAN THE ECMWF. A WEAK COLD FRONT MOVES EAST OF THE FORECAST AREA EARLY SUNDAY. A FEW SNOW SHOWERS ARE EXPECTED IN THE EAST SUNDAY MORNING...OTHERWISE MOST AREAS ARE PARTLY TO MOSTLY CLOUDY AND DRY. HOWEVER...THERE IS SUFFICIENT MOISTURE IN A NORTHWESTERLY FLOW ALOFT FOR A SLIGHT CHANCE OF SNOW OVER THE CENTRAL...WESTERN AND SOUTHWESTERN MOUNTAINS. GUSTY DOWNSLOPE WINDS ARE EXPECTED ALONG THE FRONT RANGE OF THE ROCKIES AND ADJACENT PLAINS. TEMPERATURES COOL SEVERAL DEGREES SUNDAY BEFORE RETURNING TO NEAR SEASONAL AVERAGES MONDAY. EK && .AVIATION... MOIST NORTHWEST FLOW ALOFT WILL CONTINUE OVER MY FORECAST AREA TODAY AND TONIGHT. EXPECT GENERALLY VFR CONDITIONS IN BROKEN MID AND HIGH LEVEL CLOUDS ACROSS MOST OF THE REGION WITH SCATTERED SNOW SHOWERS CAUSING AREAS MVFR CONDITIONS AT TIMES. EXCEPTION IS EASTERN PLAINS WHERE LOW CLOUDS AND AREAS OF LIGHT SNOW WILL CONTINUE UNTIL AROUND 15Z AT KHVR AND KLWT FOR MVFR AND OCCASIONAL IFR CONDITION BEFORE CONDITIONS IMPROVE TO VFR. MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 39 25 44 24 / 10 0 10 30 CTB 38 23 39 20 / 10 10 10 30 HLN 42 24 40 22 / 20 20 20 40 BZN 42 20 39 21 / 40 10 30 50 WEY 30 12 31 16 / 50 30 30 60 DLN 40 22 41 20 / 20 20 20 50 HVR 28 14 37 17 / 30 0 10 30 LWT 35 21 40 22 / 30 0 10 30 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...COHEN SHORT TERM...ZUMPFE LONG TERM...MPJ/EK AVIATION...MPJ WEATHER.GOV/GREATFALLS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 409 AM EST TUE FEB 12 2008 .SYNOPSIS... A STORM SYSTEM WILL SPREAD LIGHT SNOW INTO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA BY TUESDAY AFTERNOON. HEAVIER SNOW IS EXPECTED OVERNIGHT ON TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THE SNOW COULD MIX WITH SLEET ACROSS THE TWIN TIERS...AND MAY CHANGE OVER TO FREEZING RAIN ACROSS PORTIONS OF NORTHEAST PENNSYLVANIA AFTER MIDNIGHT TUESDAY NIGHT. THE SYSTEM WILL DEPART WEDNESDAY MORNING WITH HIGH PRESSURE BUILDING IN FOR THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 1015 PM...APOLOGIZE FOR THE LATE ISSUANCE. LES ADVISORY FOR NRN ONEIDA HAS BEEN CANCELLED. TWEEKED MINS DOWN A TAD. MID SHIFT WILL MAKE DECISION CONCERNING WARNING/ADVISORY FOR TUES EVNT. PREV BLO... LAKE EFFECT SNOWS CONTINUE ACRS ONEIDA CTY THIS AFTN AND HAVE PUSHED NORTH OF ONONDAGA AND MADISON COUNTIES. ECHOES EXTEND INTO NWRN ONEIDA ONCE AGAIN AFTER MVG OUT FOR A GOOD CHUNK OF THE DAY. BOTH THE 12Z/18Z NAM AND LATEST RUC GUIDANCE INTENSIFY BAND THRU ABOUT MIDNIGHT OVR ONEIDA CTY AND HAVE EXTENDED ADVISORY UNTIL 05Z AS ADDNL 2-4 INCHES OF SNOW CAN BE EXPECTED. NAM BUFKIT PROFILES STILL INDICATE A LOWERING INVERSION BUT LIFT AND TRAJECTORY WILL CONTINUE FAVORABLE CONDS FOR BAND OF LAKE EFFECT FOR THIS EVENING. BAND IS SHIFTING NWRD PRESENTLY AS MODELS HAVE INDICATED AND THINK BAND WILL STAY MAINLY NORTH OF ONONDAGA AND MADISON COUNTIES THIS EVENING. CUD BE A BRIEF WAFFLE BACK IN FOR A TIME LATER BUT NOT ENUF TO CAUSE A SIGNIFICANT IMPACT SO HAVE OPTED TO ALLOW ADVISORY TO EXPIRE FOR THESE LOCATIONS AT 4PM. HIGH PRESSURE WILL BUILD IN BTWN 09Z-12Z AND EFFECTIVELY END LAKE BANDS. CUD SEE CLRNG FOR A TIME OVRNGT BFR CLD SHIELD SPREADS IN AHEAD OF NEXT STORM BY DAYBREAK. TEMPS WILL BE SEVERAL DEGREES WARMER THAN THIS MRNG BUT SHUD DROP INTO THE SINGLE DIGITS. WITH CALM WINDS UNDER SFC RIDGE...WIND CHILLS WILL NOT BE A PROBLEM. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... DEVELOPING SFC LOW IN LEE OF THE ROCKIES WILL EJECT NORTHEAST DRG THE DAY TUE INTO THE MID-MS AND OHIO VALLEYS. WARM ADVECTION PCPN SHUD BREAK ABOUT ACROSS WRN ZONES ARND 15Z AND OVERSPREAD PORTIONS OF CNY AND NEPA BY 18Z. INITIAL SNOW WILL BE FAIRLY LIGHT AS IT DEVELOPS. LOW PROGGED TO MV INTO GREAT LKS REGION DRG THE AFTN WITH PCPN AFFECTING ENTIRE FA BY 00Z WED. MVMNT OF SFC LOW THEN BCMS A LITTLE MURKY AS NAM TRANSFERS MORE OF THE ENERGY TO THE COAST WITH A DEVELOPING SFC LOW. GFS FEATURES A MORE ELONGATED SFC LOW ACRS THE MID-ATLANTIC STATES BY WED MRNG WITH INVERTED TROF AXIS BISECTING FA. GIVEN UNCERTAINTIES AND THE EFFECTS ON PTYPE AND EXPECTED QPF...HAVE SIDED CLOSE TO HPC REGARDING QPF AMNTS AND TRACK OF SFC FEATURES. THERMAL PROFILES DIFFER MARKEDLY BTWN NAM AND GFS WITH GFS ONCE AGAIN ON THE WARMER SIDE AS WE HAVE SEEN ALL WINTER. HV TRENDED TOWARD MORE OF A COMPROMISE SOLN BTWN THE TWO. INITIAL PCPN COMES IN AS ALL SNOW ON TUE AFTN/EVNG BFR STARTING TO MIX. WITH WARM LAYER NOSING IN AFTER MIDNIGHT...WILL LIKELY START TO SEE A MIX OVR NEPA WITH SLEET AND SLOWLY TRANSITIONING OVER TO MORE OF A FRZG RAIN TYPE SCENARIO. LATEST GFS WUD INDICATE WYOMING/ LACKAWANNA VALLEYS MAY CHG OVR TO ALL RAIN BUT THINK THE GFS MAY BE A LITTLE BIT OVERDONE WITH H8 TEMPS ARND +5C. FURTHER NORTH...ENUF WARM AIR MAY WORK INTO TO MIX IN SLEET WITH THE SNOW ACRS THE TWIN TIERS AND POSSIBLY SLIGHTLY FURTHER NORTH. LOOKS LIKE UP TOWARD MOHAWK VALLEY AND TUG HILL...PCPN SHUD STAY AT ALL SNOW...BUT AT THIS TIME THINK QPF WILL BE LIGHTER. WITH SO MUCH UNCERTAINTY AND AFTER COORD WITH SURROUNDING OFFICES... HAVE OPTED TO LET WINTER STORM WATCH CONTINUE FOR NOW. SHUD SEE ADVISORY CRITERIA SNOWFALL AND OR FREEZING RAIN ACROSS PART OF THE CWA. OVERALL QUESTIONS RMN TO BE SEEN OF WHAT TYPE OF ADVISORY CAN WE EXPECT...WILL ANY LOCATION BE CLOSE TO LOW-END WARNING CRITERIA FOR SNOW AND/OR ICE AND CUD WE EVEN GET 7+ INCHES IN 12 HRS TO MEET WARNING CRITERIA SNOWS. HEAVIEST SNOW LOOKS TO MV IN LATE TUE EVENING...LIGHTEN UP AFTER MIDNIGHT WITH ANOTHER HEAVIER BATCH TOWARD DAYBREAK (NOT TO MENTION THE MIX IN BETWEEN). WUD RATHER SEE 00Z RUNS THIS EVENING TO GET A BETTER HANDLE ON PTYPE, TRACK OF SYSTEM, EXTENT AND STRENGTH OF WARM AIR, ETC. BFR BREAKING OUT AREAS FOR WARNINGS. CONFIDENCE IN WARNING CRITERIA AT THIS POINT IS BLO 50% FOR ANY ONE LOCATION. AFTER SYSTEM MVS EAST...EXPECT LINGERING LIGHT SNOW SHOWERS BEHIND ALTHO LAKE EFFECT LOOKS MINIMAL WITH H8 TEMPS ONLY DROPPING TO NR -10C. HIGH PRESSURE RIDGE MVS IN AGAIN THUR MORNING. && .LONG TERM /FRIDAY THROUGH MONDAY/... COLD FRONT IS EXPECTED TO SWING THROUGH ON FRIDAY...BRINGING THE CHANCE FOR RAIN OR SNOW SHOWERS. BRIEF SHOT OF ARCTIC AIR BEHIND THIS SYSTEM TO START THE WEEKEND...WITH SOME LAKE-EFFECT SNOW SHOWERS/FLURRIES POSSIBLE FRIDAY NIGHT...BEFORE DRYING SETS IN DURING SATURDAY. THE NEXT MORE SIGNIFICANT STORM SYSTEM IS SLATED FOR SUNDAY AND MONDAY. FROM THIS EARLY VANTAGE POINT...IT APPEARS THE SYSTEM COULD HAVE A FAIR AMOUNT OF GULF AND/OR ATLANTIC MOISTURE TO WORK WITH...BUT PRECIPITATION TYPE THIS FAR OUT IS UNCERTAIN. THUS...WE INDICATED THE CHANCE FOR A WINTRY MIX. && .AVIATION /09Z TUESDAY THROUGH 06Z WEDNESDAY/... LINGERING MVFR POSSIBLE THROUGH ABOUT DAYBREAK AT KSYR/KRME...OTHERWISE VFR THROUGH MIDDAY. SNOW DEVELOPS THIS AFTERNOON FROM SOUTH TO NORTH...WITH MVFR/IFR RESTRICTIONS AREA- WIDE BY 21Z. FROM LATE TONIGHT THROUGH SATURDAY... MIXED PRECIP AND IFR LIKELY AT MOST SITES LATE TONIGHT...WITH MAINLY RAIN FORESEEN AT KAVP BY THIS TIME. WEDNESDAY MORNING...MIXED PRECIP LINGERS...BEFORE TAPERING OFF TO RAIN/SNOW SHOWERS BY/DURING THE AFTERNOON. WEDNESDAY NIGHT...EXPECT IMPROVEMENT TO VFR AT ALL SITES...WITH RME/SYR BEING THE LAST TO IMPROVE. VFR CONDITIONS SHOULD CONTINUE THROUGH THURSDAY NIGHT... BEFORE A COLD FRONT MOVES THROUGH FRIDAY/FRIDAY NIGHT...WITH RESTRICTIONS POSSIBLE IN SNOW SHOWERS. IMPROVEMENT BACK TO VFR POSSIBLE BY SATURDAY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 9 AM EST WEDNESDAY FOR PAZ038>040-043-044-047-048-072. NY...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 9 AM EST WEDNESDAY FOR NYZ022>025-044>046-055>057-062. WINTER STORM WARNING FROM 11 AM THIS MORNING TO 9 AM EST WEDNESDAY FOR NYZ009-015>018-036-037. && $$ SYNOPSIS...PVB NEAR TERM...PVB SHORT TERM...PVB LONG TERM...MLJ AVIATION...MLJ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 641 PM EST MON FEB 11 2008 .SYNOPSIS... LAKE EFFECT SNOW WILL CONTINUE OVER ONEIDA COUNTY THIS EVENING WITH SEVERAL MORE INCHES OF SNOW EXPECTED BEFORE WEAKENING LATE TONIGHT. THE NEXT STORM SYSTEM WILL SPREAD LIGHT SNOW INTO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA BY TUESDAY AFTERNOON. HEAVIER SNOW IS EXPECTED OVERNIGHT ON TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THE SNOW COULD MIX WITH SLEET ACROSS THE TWIN TIERS...AND MAY CHANGE OVER TO FREEZING RAIN ACROSS PORTIONS OF NORTHEAST PENNSYLVANIA AFTER MIDNIGHT TUESDAY NIGHT. THE SYSTEM WILL DEPART WEDNESDAY MORNING WITH HIGH PRESSURE BUILDING IN FOR THURSDAY. && .NEAR TERM /THROUGH TUESDAY/... LAKE EFFECT SNOWS CONTINUE ACRS ONEIDA CTY THIS AFTN AND HAVE PUSHED NORTH OF ONONDAGA AND MADISON COUNTIES. ECHOES EXTEND INTO NWRN ONEIDA ONCE AGAIN AFTER MVG OUT FOR A GOOD CHUNK OF THE DAY. BOTH THE 12Z/18Z NAM AND LATEST RUC GUIDANCE INTENSIFY BAND THRU ABOUT MIDNIGHT OVR ONEIDA CTY AND HAVE EXTENDED ADVISORY UNTIL 05Z AS ADDNL 2-4 INCHES OF SNOW CAN BE EXPECTED. NAM BUFKIT PROFILES STILL INDICATE A LOWERING INVERSION BUT LIFT AND TRAJECTORY WILL CONTINUE FAVORABLE CONDS FOR BAND OF LAKE EFFECT FOR THIS EVENING. BAND IS SHIFTING NWRD PRESENTLY AS MODELS HAVE INDICATED AND THINK BAND WILL STAY MAINLY NORTH OF ONONDAGA AND MADISON COUNTIES THIS EVENING. CUD BE A BRIEF WAFFLE BACK IN FOR A TIME LATER BUT NOT ENUF TO CAUSE A SIGNIFICANT IMPACT SO HAVE OPTED TO ALLOW ADVISORY TO EXPIRE FOR THESE LOCATIONS AT 4PM. HIGH PRESSURE WILL BUILD IN BTWN 09Z-12Z AND EFFECTIVELY END LAKE BANDS. CUD SEE CLRNG FOR A TIME OVRNGT BFR CLD SHIELD SPREADS IN AHEAD OF NEXT STORM BY DAYBREAK. TEMPS WILL BE SEVERAL DEGREES WARMER THAN THIS MRNG BUT SHUD DROP INTO THE SINGLE DIGITS. WITH CALM WINDS UNDER SFC RIDGE...WIND CHILLS WILL NOT BE A PROBLEM. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... DEVELOPING SFC LOW IN LEE OF THE ROCKIES WILL EJECT NORTHEAST DRG THE DAY TUE INTO THE MID-MS AND OHIO VALLEYS. WARM ADVECTION PCPN SHUD BREAK ABOUT ACROSS WRN ZONES ARND 15Z AND OVERSPREAD PORTIONS OF CNY AND NEPA BY 18Z. INITIAL SNOW WILL BE FAIRLY LIGHT AS IT DEVELOPS. LOW PROGGED TO MV INTO GREAT LKS REGION DRG THE AFTN WITH PCPN AFFECTING ENTIRE FA BY 00Z WED. MVMNT OF SFC LOW THEN BCMS A LITTLE MURKY AS NAM TRANSFERS MORE OF THE ENERGY TO THE COAST WITH A DEVELOPING SFC LOW. GFS FEATURES A MORE ELONGATED SFC LOW ACRS THE MID-ATLANTIC STATES BY WED MRNG WITH INVERTED TROF AXIS BISECTING FA. GIVEN UNCERTAINTIES AND THE EFFECTS ON PTYPE AND EXPECTED QPF...HAVE SIDED CLOSE TO HPC REGARDING QPF AMNTS AND TRACK OF SFC FEATURES. THERMAL PROFILES DIFFER MARKEDLY BTWN NAM AND GFS WITH GFS ONCE AGAIN ON THE WARMER SIDE AS WE HAVE SEEN ALL WINTER. HV TRENDED TOWARD MORE OF A COMPROMISE SOLN BTWN THE TWO. INITIAL PCPN COMES IN AS ALL SNOW ON TUE AFTN/EVNG BFR STARTING TO MIX. WITH WARM LAYER NOSING IN AFTER MIDNIGHT...WILL LIKELY START TO SEE A MIX OVR NEPA WITH SLEET AND SLOWLY TRANSITIONING OVER TO MORE OF A FRZG RAIN TYPE SCENARIO. LATEST GFS WUD INDICATE WYOMING/ LACKAWANNA VALLEYS MAY CHG OVR TO ALL RAIN BUT THINK THE GFS MAY BE A LITTLE BIT OVERDONE WITH H8 TEMPS ARND +5C. FURTHER NORTH...ENUF WARM AIR MAY WORK INTO TO MIX IN SLEET WITH THE SNOW ACRS THE TWIN TIERS AND POSSIBLY SLIGHTLY FURTHER NORTH. LOOKS LIKE UP TOWARD MOHAWK VALLEY AND TUG HILL...PCPN SHUD STAY AT ALL SNOW...BUT AT THIS TIME THINK QPF WILL BE LIGHTER. WITH SO MUCH UNCERTAINTY AND AFTER COORD WITH SURROUNDING OFFICES... HAVE OPTED TO LET WINTER STORM WATCH CONTINUE FOR NOW. SHUD SEE ADVISORY CRITERIA SNOWFALL AND OR FREEZING RAIN ACROSS PART OF THE CWA. OVERALL QUESTIONS RMN TO BE SEEN OF WHAT TYPE OF ADVISORY CAN WE EXPECT...WILL ANY LOCATION BE CLOSE TO LOW-END WARNING CRITERIA FOR SNOW AND/OR ICE AND CUD WE EVEN GET 7+ INCHES IN 12 HRS TO MEET WARNING CRITERIA SNOWS. HEAVIEST SNOW LOOKS TO MV IN LATE TUE EVENING...LIGHTEN UP AFTER MIDNIGHT WITH ANOTHER HEAVIER BATCH TOWARD DAYBREAK (NOT TO MENTION THE MIX IN BETWEEN). WUD RATHER SEE 00Z RUNS THIS EVENING TO GET A BETTER HANDLE ON PTYPE, TRACK OF SYSTEM, EXTENT AND STRENGTH OF WARM AIR, ETC. BFR BREAKING OUT AREAS FOR WARNINGS. CONFIDENCE IN WARNING CRITERIA AT THIS POINT IS BLO 50% FOR ANY ONE LOCATION. AFTER SYSTEM MVS EAST...EXPECT LINGERING LIGHT SNOW SHOWERS BEHIND ALTHO LAKE EFFECT LOOKS MINIMAL WITH H8 TEMPS ONLY DROPPING TO NR -10C. HIGH PRESSURE RIDGE MVS IN AGAIN THUR MORNING. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... OPERATIONAL GFS AND ECMWF IN FAIRLY GOOD AGREEMENT FOR THE PD. QUICK WRM UP THU AHD OF A CLIPPER SYSTEM MVG THRU THE NRN LAKES. COLD FNT PASSES LATE THU SO ANY PCPN THU NGT SHD BE SOME LEFTOVER SNOW IN THE COLDER AIR. HIPRES BLDS IN FOR SAT WITH QUITE CHILLY AIR ONCE AGAIN...H8 TEMPS LWR THAN -20C. SAT MRNG MAY BE THE COLDEST MRNG OF THE WINTER. DEEP COLD AIR IS SHRT LIVED AS A COMPLEX LOW APRCHS FROM THE SOUTH WITH THE PTNL FOR CSTL DVLPMT ON SUN. WILL FCST SNOW TO BEGIN DURING SUN. SYSTEM WILL NEED TO BE WATCHED. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS THROUGH TOMORROW MORNING AT ITH/BGM/ELM/AVP. AT KRME...LAKE EFFECT SNOW BAND HAS LIFTED NORTH OF THE TERMINAL THIS EVENING. EXPECT IT TO REMAIN JUST NORTH OF THE AREA FOR A FEW HOURS BEFORE IT DRIFTS BACK SOUTH...AND BRINGS MVFR CONDITIONS BETWEEN 3 AND 9 Z WITH SOME OCCASIONAL IFR BETWEEN 3 AND 6Z. AT SYR...EXPECT THE SOUTHWARD MOVING BAND TO SPREAD MVFR RESTRICTIONS BETWEEN 5 AND 10Z...AND EVEN HERE COULD SEE SOME IFR VSBYS BETWEEN 5 AND 8Z. SNOW WILL SPREAD FROM SOUTHWEST TO NORTHEAST ACROSS THE SITES ON TUESDAY MORNING...REACHING AVP BY 15Z...ITH/BGM/ELM BY 16-17Z AND SYR/RME BY 20-21Z. EXPECT RAPID DETERIORATION TO IFR VSBYS AND MVFR CIGS. EXPECT CONDITIONS TO DROP TO LIFR AFTER A FEW HOURS...BUT GIVEN HOW FAR OUT THE FORECAST IS BY THAT POINT...AND SOME UNCERTAINTY IN START TIME...HAVE USED PROB30 GROUPS FOR LIFR AT ITH/ELM/BGM FOR THE LAST 6 HOURS OF THE TAF PERIOD. AT AVP...HAVE HIGHER CONFIDENCE...SO HAVE INTRODUCED LIFR CONDITIONS AFTER 19Z. FOR THE TUESDAY NIGHT THROUGH SATURDAY TIMEFRAME... SNOW WILL GRADUALLY CHANGE TO MIXED PRECIP TUESDAY NIGHT WITH IFR CONDITIONS LIKELY TO CONTINUE AT ALL SITES. ELM/BGM AND ESPECIALLY AVP SHOULD SEE SOME FORM OF A CHANGEOVER...WHICH COULD ACTUALLY BRING VSBYS BACK UP TO MVFR. WEDNESDAY MORNING...MIXED PRECIP/SNOW CHANGES BACK TO ALL SNOW AND TAPERS OFF FROM WEST TO EAST DURING THE AFTERNOON. EXPECT MORNING IFR RESTRICTIONS TO IMPROVE TO MVFR DURING THE AFTERNOON. WEDNESDAY NIGHT...EXPECT IMPROVEMENT TO VFR AT ALL SITES WITH RME/SYR BEING THE LAST TO IMPROVE. VFR CONDITIONS SHOULD CONTINUE THROUGH THURSDAY NIGHT BEFORE A COLD FRONT MOVES THROUGH FRIDAY/FRIDAY NIGHT WITH RESTRICTIONS POSSIBLE IN SHSN. FOR SATURDAY LAKE EFFECT CLOUDS/SHSN COULD VERY WELL ALLOW THE MVFR CONDITIONS TO CONTINUE AT ALL SITES EXCEPT PERHAPS AVP. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY MORNING FOR PAZ038>040-043-044-047-048-072. NY...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY MORNING FOR NYZ009-015>018-022>025-036-037-044>046- 055>057-062. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ009-037. && $$ SYNOPSIS...PVB NEAR TERM...PVB SHORT TERM...PVB LONG TERM...DGM AVIATION...JMA ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 649 PM EST TUE FEB 12 2008 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS THE STATE OF OHIO TONIGHT...AND INTO NEW ENGLAND WEDNESDAY. A LARGE AREA OF HIGH PRESSURE WILL MOVE INTO THE OHIO VALLEY WEDNESDAY NIGHT. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LOW PRESSURE SYSTEM JUST WEST OF CINCINNATI. CURRENT 3 HOUR HEIGHT FALLS TRACK LOW RIGHT ACROSS CLE INTO THE CENTER OF LAKE ERIE. THE CURRENT TRACK OF THE LOW IS APPROXIMATELY 150 MILES NORTHWEST OF THE GFS/NAM TRACK. CURRENTLY EVERYTHING SOUTH OF A MNN TO BJJ LINE IF FREEZING RAIN OF SLEET. WITH THE CURRENT TRACK OF THE LOW EXPECT NW OH TO GET BURST OF HEAVY SNOW THIS EVENING...THEN ENDING BY MIDNIGHT. THE REST OF OHIO AND NW PA SHOULD SEE SEVERAL HOURS OF FREEZING RAIN AND SLEET...BEFORE TRANSITIONING BACK TO SNOW LATE THIS EVENING AS THE LOW MOVES EAST OF THE AREA. THERE WILL ALSO BE A BRIEF PERIOD OF RAIN OVER NE OH/NW PA. THE FREEZING RAIN/RAIN TRANSITION LINE IS NOW BETWEEN ZANESVILLE AND NEW PHIL. NOW SURE HOW FAR NORTH THE SFC WARMING WILL REACH. OF ALL THE MODELS THE RUC SEEMS TO BE HANDLING THE LOW THE BEST. IT HAS THE LOW NORTH OF ERIE PA BY 06Z. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... FOR OVERNIGHT LOWS EXPECT SOME WARMING ACROSS NE OH/NW PA THIS EVENING THEN DROPPING AFTER MIDNIGHT. AS FAR AS PRECIP BY MIDNIGHT SNOW SHOULD BE OVER NW OH...AND TRANSITIONED BACK TO SNOW ELSEWHERE. EXPECT ONLY A FEW LINGERING SNOW SHOWERS ACROSS THE SNOWBELT TOMORROW MORNING. GET A BREAK TOMORROW NIGHT AND THURSDAY AS MODELS IN GOOD AGREEMENT MOVING LOW PRESSURE SYSTEM ACROSS THE OHIO VALLEY. BUT THE BREAK WILL BE SHORT LIVED. THE ECMWF...GFS...AND NAM HAVE NEXT FRONT MOVING INTO NW OHIO BY FRIDAY MORNING. && .LONG TERM /FRIDAY THROUGH TUESDAY/... EXTENDED PERIOD BEGINS FRIDAY 12Z WITH LOW PRESSURE ACROSS THE EASTERN LAKES WITH A COLD FRONT JUST TO OUR NORTHWEST. WILL NEED TO START OUT WITH A MIX OF EITHER RAIN OR SNOW GIVEN 850MB TEMPS FLIRTING WITH 0C. IN THE WAKE OF THE LOW COLD AIR WILL MOVE INTO THE AREA BEHIND A COLD FRONT AND TURN ANY REMAINING MIX BACK TO ALL SNOW FOR THE AFTERNOON. HIGH PRESSURE WILL BUILD IN FOR THE BEGINNING OF THE WEEKEND BUT SUNDAY NIGHT INTO MONDAY ECMWF AND GFS DEVELOP ANOTHER WINTER STORM WHICH MOVES OUT OF THE GULF COAST STATES. QUESTION AT THIS POINT WILL BE THE STORM TRACK. GFS TAKES THE LOW TO THE EAST COAST WHILE THE ECMWF MOVES IT THROUGH THE OHIO VALLEY SUNDAY NIGHT. BOTH WILL PROBABLY BE CORRECT WITH THE INITIAL LOW MOVING INTO THE OHIO VALLEY WITH THE ENERGY THEN TRANSLATING TO THE COAST. WILL BRING CHC POPS FOR NOW AND GO WITH ALL SNOW BASED ON 850MB TEMPS. MONDAY WOULD EXPECT WRAP AROUND MOISTURE TO CONTINUE A SMALL CHANCE OF SNOW SHOWERS. WILL CONTINUE CLOUDY ON TUESDAY BUT SHOULD BE IMPROVING CONDITIONS THROUGHOUT THE DAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE NEAR MFD MOVING ENE. MAINLY IFR CONDITION ACROSS THE AREA WITH MIXED PRECIP...MAINLY SNOW FAR WEST FREEZING RAIN OR RAIN ELSEWHERE. PRECIP IN EAST LIKELY TO CHANGE TO ALL RAIN FOR AWHILE AS LOW TRACKS ENE...THEN TRANSITION BACK TO SNOW BEFORE TAPERING OFF A FEW HOURS AFTER LOW PASSES. CIGS AND VSBY SHOULD LIFT TO MAINLY MVFR LATE TONIGHT. COULD BE LIGHT FREEZING DRIZZLE FOR FEW HOURS AFTER SNOW ENDS. DURING THE DAY TOMORROW HIGH PRESSURE BUILD IN BUT BELIEVE MOISTURE TRAPPED BELOW INVERSITION WILL KEEP MVFR CIGS. .OUTLOOK... SKIES LIKELY TO CLEAR OR LEAST GO VFR TOMORROW NIGHT AS HIGH PRESSURE SLIDES ACROSS THE AREA AND WINDS BACK TO THE SOUTHWEST. COULD SEE SOME MVFR SNOW SHOWERS WITH A COLD FRONT ON FRIDAY BUT SHOULD SEE RETURN TO VFR SATURDAY WITH HIGH PRESSURE. NON VFR CONDITIONS LIKELY WITH A COLD FRONT AND SNOW SHOWERS ON SUNDAY. && .MARINE... LOW TRACKING INTO THE OHIO VALLEY IS FURTHER WEST THAN ORIGINALLY THOUGHT...NOW WITH AN ANTICIPATED TRACK THROUGH CENTRAL OHIO TO NEAR CLEVELAND. THIS WILL TAKE THE CIRCULATION OVER THE LAKE AND THEREFORE THE LAKE WILL EXPERIENCE A SHIFT FROM CURRENTLY EASTERLY WINDS AROUND THE DIAL TO THE WEST-NORTHWEST BY WEDNESDAY MORNING AS THE LOW PULLS AWAY. HIGH PRESSURE BUILDS IN SOUTH OF THE OHIO RIVER THURSDAY BRINGING WINDS ON THE LAKE AROUND TO THE SOUTHWEST. LOW PRESSURE THAT MOVES ACROSS THE CENTRAL LAKES WILL TAKE A COLD FRONT SOUTHEAST ACROSS THE LAKE FRIDAY. HIGH PRESSURE FROM THE NORTHERN PLAINS FOLLOWS FOR SATURDAY. FORECAST FOR SUNDAY GETS MORE DIFFICULT WITH MODEL DIFFERENCES. TWO SYSTEMS...A NORTHERN STREAM AND A SOUTHERN STREAM SYSTEM WILL AFFECT THE EASTERN HALF OF THE U.S. FOR NOW HAVE THE NORTHERN STREAM A LITTLE FASTER AND THEREFORE HAVE SOUTHWEST FLOW AHEAD OF THAT SYSTEM FOR SUNDAY. THROUGHOUT THE PERIOD WINDS LOOK TO REMAIN AT 25 KNOTS OR LESS WITH THE WINDIEST DAY LOOKING TO BE FRIDAY AND FRIDAY EVENING. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...WINTER STORM WARNING UNTIL 11 PM EST THIS EVENING FOR OHZ003- 006>014-017>023-027>033-036>038-047-089. PA...WINTER STORM WARNING UNTIL 11 PM EST THIS EVENING FOR PAZ001>003. MARINE...NONE. && $$ SYNOPSIS...DJB NEAR TERM...DJB SHORT TERM...DJB LONG TERM...TK AVIATION...RANDEL MARINE...OUDEMAN oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 849 AM CST MON FEB 11 2008 .DISCUSSION... CONVECTIVE ELEMENTS CONTINUE WITHIN LOW LEVEL JET AXIS AND ON EDGE 850MB MOISTURE PLUME WITH ELEVATED INSTABILITIES SUPPORTING CONTINUED CONVECTIVE NATURE OF DEVELOPING PRECIP. WEAK SURFACE LOW NOTED OVER FAR EASTERN OKLAHOMA...WITH WEDGE OF COLDEST AIR RAPIDLY ERODING EARLY THIS MORNING IN ADVANCE OF THIS FEATURE. LATEST NAM/RUC BOTH MAINTAIN THIS WEAK LOW SIGNATURE ACROSS EASTERN OKLAHOMA...WITH ADDITIONAL SURFACE WAVES LIKELY ALONG THE FRONTAL BOUNDARY LATER THIS AFTERNOON AND EVENING. RESULTANT FLOW AND EXPECTED CLOUD COVER WILL LIKELY KEEP THE COLD WEDGE IN PLACE NORTH OF INTERSTATE 44...WITH LARGE GRADIENT IN AFTERNOON TEMPERATURES EXPECTED ACROSS THE FORECAST AREA. THUS HAVE ADJUSTED TEMPERATURES ACCORDINGLY AND NEAREST THE LATEST RUC SOLUTIONS. REGARDING ADDITIONAL ICING...CONVECTION CONTINUES TO DEVELOP WITHIN JET AXIS WITH THE FOCUS FOR MORE WIDESPREAD ACTIVITY SHIFTING TO OUR NORTHEAST. HOWEVER EVEN WITH THE DECREASING COVERAGE...ANY ADDITIONAL ICING WILL CAUSE AT LEAST TRAVEL PROBLEMS....AND CURRENT HEADLINES MAY BE EXTENDED FURTHER INTO THE AFTERNOON IF TRENDS WARRANT. && .PRELIMINARY POINT TEMPS/POPS... TUL 38 29 45 22 / 70 60 10 0 FSM 47 36 47 23 / 70 90 10 0 MLC 49 35 48 25 / 50 80 10 0 BVO 37 26 43 20 / 70 40 0 0 FYV 44 30 40 19 / 80 80 10 0 BYV 44 29 37 20 / 80 80 10 0 MKO 43 32 45 22 / 80 70 10 0 MIO 38 26 38 21 / 70 50 10 0 F10 42 31 45 24 / 60 70 0 0 HHW 55 38 51 26 / 40 80 20 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER STORM WARNING UNTIL NOON MONDAY FOR OKZ055-OKZ056-OKZ057- OKZ058-OKZ063. WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR OKZ054-OKZ059- OKZ060-OKZ061-OKZ062-OKZ064-OKZ066-OKZ067-OKZ070. AR...WINTER STORM WARNING UNTIL NOON MONDAY FOR ARZ001-ARZ002. WINTER WEATHER ADVISORY UNTIL NOON MONDAY FOR ARZ011. && $$ SHORT TERM...07 LONG TERM....23 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1008 PM EST TUE FEB 12 2008 .SYNOPSIS... LOW PRESSURE CENTERED OVER EASTERN ARKANSAS LATE THIS MORNING WILL NORTHEAST INTO THE OHIO VALLEY TONIGHT...REACHING THE LOWER GREAT WEDNESDAY MORNING. THIS STORM WILL BRING SNOW FOLLOWED BY A WINTRY MIX OF PRECIPITATION TO CENTRAL PENNSYLVANIA THIS AFTERNOON INTO WEDNESDAY. HIGH PRESSURE WILL BUILD OVER THE STATE THURSDAY. A COLD FRONT WILL PUSH THROUGH ON FRIDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... RADAR TRENDS SHOWING CONVEYOR BELT OF MOISTURE NOSING INTO THE SOUTH CENTRAL MOUNTAINS AND THE LOWER TO MIDDLE SUSQUEHANNA RIVER VALLEY FOR THE OVERNIGHT. SHORT TERM MODELS NOT HANDLING THIS SURGE WELL IN THE NEAR TERM...BUT RUC FINALLY CATCHES ON WITH OVER ONE THIRD OF AN INCH QPF BY 12Z OVER MY SOUTHEAST AREAS. QUICK UPGRADE TO ICE STORM WARNING FOR MY SOUTHEASTERN THIRD IS IN ORDER WITH SFC TEMPS IN THE LOWER TO MIDDLE 20S AS CONVECTIVE ELEMENTS WILL CONTINUE TO LIFT ACROSS THE REGION FOR THE NEXT 6 TO 9 HOURS. ELSEWHERE...EXPECT FREEZING RAIN TO INCREASE IN COVERAGE AS COLD AIR ADVANCES FROM THE WEST INCREASING SFC CONVERGENCE OVER CENTRAL PA. MANY OF THESE AREAS WILL SEE BETWEEN ONE AND TWO TENTHS OF AN INCH OVERNIGHT AND WILL HAVE TO BE MONITORED FOR POTENTIAL UPGRADES TO WARNINGS THROUGHOUT THE OVERNIGHT HOURS...AGAIN BASED PRIMARILY ON RADAR EVOLUTION. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... SREF 850 WIND VEERING TO THE WEST ACROSS WRN PENN AROUND 12Z WED. OVER THE SUSQ VALLEY...WEAK COASTAL DEVELOPMENT WILL HOLD THE PRECIP BACK TO AROUND 16-18Z. THIS WILL BE FOLLOWED BY WEAK LOW TO MID LEVEL COLD ADVECTION AND A SLOW LIFTING OF THE CLOUD BASE. CLOUDY SKIES WITH LITTLE OR NO PRECIP WILL OCCUR DURING THE AFTERNOON HOURS...OUTSIDE OF RAIN SHOWERS MIXING WITH SOME WET SNOW SHOWERS ACROSS THE EAST...AND SCATTERED LIGHT SNOW SHOWERS ACROSS THE WESTERN MTNS (WHERE THE SUBSIDENCE INVERSION BASE AND HIGH MOISTURE WILL BE 3 KFT AGL OR LESS). && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... RIDGING AT SFC AND ALOFT SHOULD PROVIDE FAIR AND SEASONAL CONDS THURSDAY. A COLD FRONT COULD BE ACCOMPANIED BY SCT SNOW SHWRS OVR THE ALLEGHENY HIGHLANDS FRIDAY. MED RANGE ENS DATA CONTINUES TO SUGGEST THE CHC FOR A SIG PRECIP EVENT IN THE SUN NITE TO MON NITE TIMEFRAME...AS DIGGING TROF OVR THE MIDWEST SPAWNS AN EAST COAST STORM. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... INTENSE BANDS OF SNOW OVER THE AREA AT MID AFTERNOON NOW QUICKLY MOVING NORTH OUT OF THE AREA. THE SNOW CAME DONW HARD AT TIMES...WITH ONE REPORT OF 2 INCHES IN LESS THAN AN HOUR ALONG RTE 30 IN YORK CO...ALONG WITH SOME THUNDER. MOST AREAS WILL SEE SPOTTY LIGHT FREEZING RAIN AND DRIZZLE BY MIDNIGHT...WITH IFR AND EVEN SOME LIFR CONDITIONS OVERNIGHT. SOME IMPROVEMENT ON WED...AS TEMPS WARM...ANY REMAINING PRECIPITATION WILL BE ON THE LIGHT SIDE. CONDITIONS MAINLY IN THE IFR AND MVFR RANGE...AS THE COASTAL LOW TAKES OVER. THE UPR TROF PUSHES EAST OF THE AREA BY THUR WITH IMPROVEMENT XPECTED OVER MUCH OF THE AREA. SOME LOW CIGS/-SHSN MAY LINGER AT JST/BFD. A RETURN TO VFR LATER THUR INTO EARLY FRIDAY AS HIGH PRES BRIEFLY BUILDS INTO THE REGION. ANOTHER LOW PRES SYS AND ATTENDANT FRONT ARE FCST TO MOVE THRU FRI INTO SAT ACCOMPANIED BY REDUCED CIGS/VIS IN RA/SN SHWRS. LINGERING -SHSN IN THE WAKE OF THE FROPA COULD KEEP BFD/JST MVFR THRU EARLY SAT. && .EQUIPMENT... SOME MINOR THINGS EARLIER...HAD TO BRUSH OFF THE SBN DISH... BUT OK NOW. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST WEDNESDAY FOR PAZ004>006-010>012-017>019-024>027-033>035-037-041-042-045-046. ICE STORM WARNING UNTIL 9 AM EST WEDNESDAY FOR PAZ028-036- 049>053-056>059-063>066. && $$ SYNOPSIS...TYBURSKI NEAR TERM...DEVOIR SHORT TERM...RXR/TYBURSKI LONG TERM...TYBURSKI AVIATION...MARTIN/RXR pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1032 AM EST TUE FEB 12 2008 .SYNOPSIS... HIGH PRESSURE WILL MOVE OFFSHORE TODAY AS LOW PRESSURES ALONG A COLD FRONT APPROACHES FROM THE WEST. THE FRONT WILL CROSS OUR REGION EARLY WEDNESDAY FOLLOWED BY HIGH PRESSURE CROSSING THE EASTERN STATES...THEN OFF THE MID ATLANTIC COAST ON FRIDAY. ANOTHER LOW PRESSURE WILL APPROACH THE CAROLINAS FROM THE GULF THIS WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030 MB HIGH PRES CENTER REMAINS NORTH OF THE REGION THIS MORNING...WITH A SLOW NORTHWARD ADVANCE OF A WARM FRONT ACROSS THE DEEP SOUTH. EARLY DAY RADAR RETURNS INDICATED SPRINKLES FALLING FROM A MID DECK...BUT NOT REACHING THE GROUND. THIS INITIAL WAVE WILL LIFT NORTH OF THE REGION THROUGH THE AFTERNOON...WITH LOWER AND MID LEVEL MOISTURE SLOWLY SPREADING IN WELL AHEAD OF THE MS RIVER VALLEY SYSTEM. AN ATLANTIC FETCH PLUME OF MOISTURE IS STILL EXPECTED TO AFFECT THE INTERSTATE 77 CORRIDOR WELL AHEAD OF THE DEEPER MOISTURE WITH THE FRONTAL SYSTEM. WILL THUS MAINTAIN HEALTHY CHANCE POPS IN ERN PIEDMONT SECTION BY LATE AFTERNOON...WITH CHANCE POPS RAMPING UP IN SOUTHERLY FLOW ESCARPMENT LOCATIONS AS WELL. MORNING UPPER AIR ANALYSIS INDICATED A 50+ KT 850 MB JET SLOWLY TRANSLATING EASTWARD AHEAD OF THE MS VALLEY SYSTEM. WINDS ALONG THE HIGH RIDGE TOPS WILL STEADILY INCREASE...WITH GUSTS 30 TO 40 KT LIKELY BY LATE AFTERNOON. WILL CONTINUE THE EXISTING LAKE WIND ADVISORY THROUGH THIS AFTERNOON...WHICH MAY NEED EXTENSION INTO TONIGHT...PENDING REVIEW OF 12Z MODEL SUITE. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... AS OF 315 AM TUESDAY...BEST ISENTROPIC LIFT AREA MOVES INTO THE NC PIEDMONT AND FOOTHILLS AFTER 00Z WED WHILE H92-H85 UPSLOPE FLOW INCREASES ACROSS THE S FACING MOUNTAIN SLOPES. POPS WILL INCREASE OVERNIGHT AS COLD FRONT APPROACHES AND REACHES THE WESTERN MOUNTAIN COUNTIES BY 12Z. THE H85 JET CORE SHIFTS TO THE NORTH AND A GENERAL DECREASE IN SFC WINDS IS EXPECTED AHEAD OF THE FROPA...UNTIL STRONG CAA WINDS KICK IN AROUND 18Z WED. NAMKIT SOUNDINGS SHOW MOMENTUM TRANSFERS ON THE ORDER OF 35 TO 45 KTS BETWEEN 20Z WED AND 06Z THU AND A WIND ADVISORY WILL PROBABLY BE NEEDED ACROSS THE MOUNTAINS WED AFTERNOON THROUGH EARLY THU. NICE THETA/E ADVECTION AHEAD OF THE COLD FRONT WILL KEEP THE LLVLS TOO WARM FOR ANY P/TYPE CONCERNS. A BLEND OF MODEL NOMOGRAMS SHOW THE A GOOD POSSIBILITY OF A IP/SN MIX ACROSS THE MOUNTAINS NORTH OF I-40 AFTER 18Z WED ASSOCIATED WITH THE LLVL CAA AND THE GRIDS HAVE BEEN MODIFIED TO INCLUDE THIS. THIS WILL BE AROUND THE SAME TIME DEEP LAYERED MOISTURE WANES SO WILL NOT EXPECT MUCH IF ANY ACCUMULATION...ESPECIALLY WITH AN EXISTING WET GROUND. THE NC/TN BORDER COUNTY AREA ALONG THE NORTHERN MOUNTAINS COULD SEE UP TO HALF INCH OF SN THROUGH 06Z THU AS -SNSH SHOULD CONTINUE IN A SHORT NW FLOW REGIME. TEMPERATURES WILL DROP TO BELOW FREEZING ACROSS THE MOUNTAIN VALLEYS AFTER 02Z THU AND ABOUT 4-5 HOURS BEFORE THIS IN THE HIGHER ELEVATIONS...SO BLACK ICE COULD CERTAINLY BE AN ISSUE WITH THE MORNING COMMUTES THU MORNING THROUGH 10Z. EXPECT MAXIMUM TEMPERATURES TO REBOUND NICELY A FEW DEGREES ABOVE NORMAL THU. THE H85 THERMAL TROF QUICKLY LIFTS NORTH WITH H5 FLAT RIDGING BUILDING IN FROM THE WEST AND SFC HIGH GETS SHUNTED TO THE COAST ALLOWING GOOD INSOLATION AND A BIT OF AFTERNOON SOUTHERLY FLOW. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 230 AM TUESDAY...BOTH THE GFS AND ECMWF HAVE THE HIGH PRESSURE CENTER MOVING OFF THE MID ATLANTIC COAST THURSDAY EVENING. THIS HIGH PRESSURE MAINTAINS A RIDGE INTO THE CAROLINAS INTO MID DAY FRIDAY...THEN GIVES AWAY TO LOW PRESSURE AND A FRONT APPROACHING FROM THE WEST. THE MODEL SOLUTIONS DIFFER GOING INTO THE WEEKEND. ON THE GFS...THE COLD FRONT MOVES JUST SOUTH OF OUR AREA FRIDAY NIGHT AS HIGH PRESSURE MOVES WEST TO EAST ACROSS THE OHIO RIVER VALLEY INTO SATURDAY. SURFACE LOW PRESSURE WILL BE FORMING AHEAD OF A CUT OFF UPPER LOW ON SATURDAY THEN START MOVING NORTHEAST ACROSS THE LOWER MISSISSIPPI SATURDAY NIGHT. AT 12Z SUNDAY...HIGH PRESSURE WILL WEDGE IN FROM THE MID ATLANTIC ACROSS THE CAROLINAS AS THE LOW PRESSURE SPREADS IN MOISTURE FROM THE WEST. WE WILL HAVE TO WATCH FOR THE POSSIBILITY OF SOME ICE OVER PORTIONS OF WESTERN NORTH CAROLINA EARLY SUNDAY. THE LOW ON THE GFS WILL BE PASSING JUST NORTH OF OUR AREA SUNDAY EVENING WITH THE FRONT CROSSING FROM THE WEST. WRAP AROUND MOISTURE WILL REMAIN OVER THE NORTH CAROLINA MOUNTAINS WILL THE UPPER TROUGH AXIS CROSSING AND SNOW SHOWERS THROUGH MONDAY NIGHT. ON THE ECMWF...THE SYSTEM IS MUCH SLOWER IN PROGRESSING ACROSS THE SOUTHEAST AND TAKES A MORE SOUTHERN TRACK AS COMPARED TO LAST NIGHTS RUN. AT 12Z SATURDAY...THIS MODEL MAINTAINS LIGHT PRECIP OVER THE MOUNTAINS THEN KEEPS ALL PRECIP TO OUR WEST UNTIL EARLY SUNDAY. EARLY SUNDAY...THE CENTER OF THE HIGH IS ON THE NEW ENGLAND COAST AND BRINGS COOLER THICKNESSES INTO THE CAROLINAS AHEAD OF THE APPROACHING LOW FROM THE SOUTHWEST. HOWEVER...THIS PERIOD OF POSSIBLE WINTRY PRECIP IS RATHER BRIEF AS WARM AIR ADVECTION WILL PREVAIL. GOOD QPF AMOUNTS ARE FORECAST TO AROUND 2 INCHES WEST OF US BUT FADES OUT A BIT AS IT GETS TO OUR AREA. THE WRAP AROUND SNOW SHOWERS WITH THIS MODEL WILL OCCUR MONDAY NIGHT AND TUESDAY...GOING INTO THE AFTER FORECAST PERIOD. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... THE LOW STRATUS LAYER CONTINUES TO HOLD IN ACROSS NC PIEDMONT/FOOTHILL LOCATIONS LATE THIS MORNING...BUT SOME DEGREE OF SCATTERING HAS OCCURRED IN THE VICINITY OF KCLT. LATEST RUC13 SOUNDINGS INDICATE IFR CIG PERSISTING AT KHKY UNTIL 17Z...WITH RAPID IMPROVEMENT THROUGH EARLY AFTN. THIS SEEMS REASONABLE GIVEN THE LACK OF MAINTENANCE UPGLIDE AND STEADILY WARMING SURFACE TEMPERATURES. ISENTROPIC LIFT AND LOW LEVEL MOISTURE WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON AND INTO THE EVENING HOURS. SCATTERED SHOWERS WILL LIKELY DEVELOP KCLT VICINITY...AND ALSO OVER THE SW MTNS. AS THE SHOWERS INCREASE...EXPECT FAIRLY WIDESPREAD MVFR CIGS TO DEVELOP AS WELL. FLOW SHOULD CONTINUE TO COME AROUND TO SOUTHERLY...BUT PROBABLY SLOWER THAN FORECAST BY MODELS AT KHKY TO KCLT WITH RESIDUAL COLD WEDGE. GREATEST PRECIPITATION CHANCES...AND ASSOCIATED WIDESPREAD IFR CIG...SHOULD DEVELOP OVERNIGHT WITH THE APPROACH OF THE FRONT. FAIRLY RAPID DRYING IS EXPECTED FROM THE WEST 12Z TO 18Z WED. AVIATION OUTLOOK...CONDITIONS WILL IMPROVE WEDNESDAY AFTERNOON AND EVENING. DRY HIGH PRESSURE WILL BUILD OVER THE REGION ON THURSDAY AND WILL REMAIN INTO FRI...KEEPING CONDITIONS VFR. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...LAKE WIND ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR NCZ033- 048>053-058-059-062>065. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...HG SHORT TERM...SBK LONG TERM...DEO AVIATION...HG/RWH sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 823 PM CST TUE FEB 12 2008 .DISCUSSION... BAND OF HIGHER MID CLOUDS PRETTY MUCH DISSIPATED AS IT MOVED EAST AWAY FROM THE JAMES VALLEY THIS EVENING...AND HAVE ADJUSTED SKY COVER TO REDUCE CENTRAL/EASTERN PORTIONS OF THE FA TO MOSTLY CLEAR OR PARTLY CLOUDY RANGE FOR THE EVENING...WITH SOME INCREASE LATER IN THE NIGHT AS NARROW BAND OF LOWER CLOUDS NOW IN THE JAMES VALLEY SLIDES EAST. WITH CLEAR SKIES AND FAIRLY LIGHT SOUTHWEST FLOW ACROSS THE EASTERN CWA...TEMPS HAVE REALLY TAKEN A NOSEDIVE DURING THE EARLY EVENING... ESPECIALLY IN TYPICAL DRAINAGE AREAS AND RIVER VALLEYS. HAVE MADE SIGNIFICANT UPDATES TO DROP LOW TEMPERATURES...THOUGH DO EXPECT TEMPS TO LEVEL OFF SOME THROUGH THE OVERNIGHT HOURS AS CLOUD BAND MOVES IN FROM THE WEST. UPDATED GRIDS/PFM/ZFP SENT EARLIER...THOUGH WILL HAVE TO KEEP A CLOSE EYE ON TEMPS IN NORTHWEST IOWA. .AVIATION... FAIRLY NARROW BAND OF MVFR CIGS FM BTWN ATY AND HON SWD THRU MHE TO W OF YKN AT 02Z MOVG EWD TO I29 CORRIDOR ARND 06Z...THEN OVER SWRN MN AND NWRN IA FM 06Z TO 09Z...FLWD BY GENLY VFR. HOWEVER...PATCHY MVFR FOG THEN PSBL OVER AREA MAINLY E OF JAMES RIVER FM 10Z TO 14Z. && .PREV DISCUSSION... MAIN FORECAST CONCERN THROUGH THE BALANCE OF THE WEEK IS CHANCES FOR PCPN WEDNESDAY NIGHT INTO THURSDAY AS SHORTWAVE AND ASSOCIATED SURFACE LOW SWING THROUGH THE REGION FROM NORTHWEST TO SOUTHEAST. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES DEPICT A FAIRLY SHARP TROUGH OVER CENTRAL NORTH AMERICA...WITH OUR AREA ON THE BACKSIDE OF THIS FEATURE AND IN A GENERAL AREA OF SUBSIDENCE AT THIS TIME. A NORTHERN STREAM SHORTWAVE WAS APPARENT DIVING SOUTHEAST FROM MANITOBA TOWARD MINNESOTA. THE FORCING ASSOCIATED WITH THIS SHORTWAVE WILL STAY NORTH AND EAST OF OUR AREA TONIGHT AS WILL THE LIMITED AREA OF DEEPER SATURATION. WE WILL SEE SOME FORCING AS THE LOW LEVEL TROUGH/WARM FRONT PUSHES EAST ACROSS THE AREA...BUT AT THIS TIME IT LOOKS LIKE WE SHOULD ONLY SEE AN INCREASE IN CLOUD COVER AND NO PCPN AS THIS SWINGS THROUGH. THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN THEIR HANDLING OF SYNOPTIC SCALE FEATURES OVER THE NEXT FEW DAYS...ALTHOUGH THERE ARE SOME MINOR DIFFERENCES IN INTENSITY AND PLACEMENT. IN GENERAL...THE GFS IS A BIT FARTHER SOUTH WITH THE BAROCLINIC ZONE WEDNESDAY NIGHT INTO THURSDAY AND ALLOWS PCPN TO EXTEND SOMEWHAT FARTHER SOUTH THAN THE NAM. IN ADDITION...THE GFS ALSO SATURATES THINGS MORE QUICKLY AND OVER A WIDER AREA THAN THE NAM...AND IS A BIT HIGHER IN ITS PREDICTED PCPN AMOUNTS AS A RESULT. UTILIZED A BLEND OF THE THE GFS AND NAM FOR THE FORECAST DETAILS...TRENDING A BIT MORE TOWARD THE GFS TO ALLOW FOR A BIT MORE PCPN SLIGHTLY FARTHER SOUTH. THERE WILL LIKELY BE A PERIOD OF SOME INCREASED CLOUD COVER FOR A TIME TONIGHT AS AN AREA OF 1000-850MB WARM ADVECTION SLIDES ACROSS THE AREA...THEN WE SHOULD BE BACK TO PARTLY CLOUDY SKIES AWAITING THE MAIN INCREASE IN CLOUD COVER AHEAD OF THE SYSTEM EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT AND THURSDAY. MID/HIGH CLOUDS DESCENDING THE UPPER RIDGE WILL SPREAD ACROSS THE AREA ON WEDNESDAY...THEN THICKEN DURING THE AFTERNOON AS LOW LEVEL RETURN FLOW SETS UP AND WARM ADVECTION INCREASES. THE 290K ISENTROPIC SURFACE SHOWS A DRAMATIC INCREASE IN UPGLIDE BY 00Z THURSDAY...WITH CONDENSATION PRESSURE DEFICITS DROPPING BELOW 50MB OVER MUCH OF THE NORTHERN CWFA. THIS PERSISTS THROUGH 06Z...WITH IMPLIED SATURATION OVER ALL BUT THE FAR SOUTH/SOUTHEAST. GOOD PACKING OF THE PRESSURE SURFACES IS INDICATED...WITH 40KT WINDS AT NEARLY A PERPENDICULAR ANGLE TO THEM...SUGGESTING A GOOD PERIOD OF ISENTROPIC ASCENT. THIS IS MAXIMIZED NORTH AND EAST OF OUR AREA...WHICH IS ALSO WHERE THE BETTER SATURATION IS EXPECTED...BUT THE NORTH AND EAST PORTIONS OF THE FORECAST AREA COULD STILL SEE SEVERAL INCHES OF SNOW WEDNESDAY NIGHT INTO THURSDAY MORNING. MIXING RATIOS OF AROUND 3.5 G/KG ARE PROGGED...BUT WITH ONLY ABOUT A 6-HR WINDOW OF GOOD ISENTROPIC ASCENT EXPECTED...FEEL IT WILL BE TOUGH FOR ANYWHERE IN OUR FORECAST AREA TO SEE MUCH MORE THAN 3.5 INCHES...AND EVEN THAT SHOULD BE CONFINED TO THE NORTH AND EAST. OVER THE SOUTH WHERE SATURATION WILL BE A BIT TOUGHER TO COME BY THERE IS SOME POTENTIAL FOR MIXED PCPN WITH AN ELEVATED WARM LAYER ADVERTISED BY THE NAM AND GFS UNTIL THINGS BECOME SUFFICIENTLY SATURATED. WILL INCLUDE A MENTION OF SOME FZRA EARLY ON TO ACCOUNT FOR THIS POSSIBILITY. THE EASTERN CWFA LOOKS LIKE IT WILL GET SOME ADDITIONAL HELP/SUPPORT FOR A BRIEF TIME THURSDAY MORNING AS FORCING ALONG THE FRONTAL BOUNDARY BRIEFLY CORRESPONDS WITH SOME UPPER DIVERGENCE IN THE EXIT REGION OF THE 110KT 300MB JET THAT WILL BE LOCATED TO OUR SOUTH. WINDS WILL INCREASE QUITE A BIT BEHIND THE FRONT...WITH 925-850MB WINDS OF 35-40KT AND GOOD COLD ADVECTION HELPING TO MIX DOWN A GOOD PORTION OF THAT. WILL INCLUDE THE MENTION OF BLOWING SNOW DURING THE DAY ON THURSDAY AS THESE STRONG WINDS SWING THROUGH THE AREA. SUBSIDENCE LOOKS LIKE IT SHOULD SCOUR OUT MOST OF THE CLOUD COVER THURSDAY NIGHT...THEN RIDGING WILL BUILD ACROSS THE REGION THROUGH FRIDAY NIGHT. IN THE SATURDAY THROUGH TUESDAY TIME FRAME THE MEDIUM RANGE GUIDANCE IS IN REASONABLE AGREEMENT ON THE EVOLUTION OF THE LONGWAVE FEATURES OVER NORTH AMERICA...ALTHOUGH THERE ARE THE EXPECTED DIFFERENCES IN THE TIMING...POSITION...AND AMPLITUDE OF INDIVIDUAL SHORTWAVES. THE HPC PROGS GENERALLY FAVOR THE ECMWF FOR THE DETAILS...AND WILL STICK FAIRLY CLOSE TO THAT IDEA...WITH SOME BLENDING TOWARD THE GOING FORECAST AS WELL AS THE OPERATIONAL GFS AND GFS ENSEMBLE. IN GENERAL...THE LONGWAVE UPPER TROUGH WILL PERSIST OVER EASTERN NORTH AMERICA...WITH RIDGING ALONG THE WEST COAST. A CUTOFF LOW IN THE SOUTHERN STREAM ON SATURDAY WILL PHASE WITH THE EASTERN UPPER TROUGH AS IT BECOME MORE AMPLIFIED BY LATE SUNDAY AND MONDAY AND THEN THE UPPER PATTERN SHOULD PROGRESS SLIGHTLY EASTWARD BY TUESDAY. ALL IN ALL...THIS WILL KEEP GENERALLY DRY NORTHWEST UPPER FLOW OVER OUR AREA THROUGHOUT THIS TIME FRAME. CHANCES FOR PCPN WILL BE DICTATED BY THE PASSAGE OF INDIVIDUAL SHORTWAVES AND FRONTAL FEATURES...WHICH WILL BE DIFFICULT TO NAIL DOWN AT THIS POINT. HOWEVER...GIVEN THE EXPECTED UPPER AIR PATTERN AND ITS GENERALLY DRY AND COOL NATURE...NO SIGNIFICANT WEATHER MAKERS APPEAR IN STORE FOR THE AREA AT THIS POINT. A CLIPPER WILL SCOOT BY TO THE NORTH AND EAST ON SATURDAY...HELPING TO BRING A REINFORCING SHOT OF COLDER TEMPERATURES ALONG WITH SOME CHANCE FOR PCPN. AT THIS POINT THE MAIN ISENTROPIC LIFT AND DPVA LOOK TO BE TO OUR NORTH AND EAST...SO WILL JUST INCLUDE A SLIGHT CHANCE FOR SNOW. IN ADDITION...TEMPERATURES ACTUALLY LOOK MARGINALLY COLD FOR SNOW...WITH SOME WARMER 925-850MB TEMPERATURES TRYING TO SNEAK IN AHEAD OF THE SHORTWAVE. GIVEN THE LOW OVERALL PROBABILITY OF PCPN...WILL ONLY MENTION SNOW AT THIS POINT...ALTHOUGH IF THERE IS ANY PCPN THERE IS SOME CHANCE THAT IT COULD BE MIXED OVER THE SOUTH. ANY FORCING AND MOISTURE WITH THIS SYSTEM SHOULD SHIFT EAST BY SUNDAY...THEN HIGH PRESSURE LOOKS LIKE IT WILL SETTLE IN ACROSS THE REGION THROUGH TUESDAY...SO WILL GO WITH A DRY FORECAST FOR SUNDAY THROUGH TUESDAY AT THIS POINT. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$ JH/RSR sd AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD ISSUED BY NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 254 PM CST TUE FEB 12 2008 .SHORT TERM... MAIN FORECAST CONCERN THROUGH THE BALANCE OF THE WEEK IS CHANCES FOR PCPN WEDNESDAY NIGHT INTO THURSDAY AS SHORTWAVE AND ASSOCIATED SURFACE LOW SWING THROUGH THE REGION FROM NORTHWEST TO SOUTHEAST. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES DEPICT A FAIRLY SHARP TROUGH OVER CENTRAL NORTH AMERICA...WITH OUR AREA ON THE BACKSIDE OF THIS FEATURE AND IN A GENERAL AREA OF SUBSIDENCE AT THIS TIME. A NORTHERN STREAM SHORTWAVE WAS APPARENT DIVING SOUTHEAST FROM MANITOBA TOWARD MINNESOTA. THE FORCING ASSOCIATED WITH THIS SHORTWAVE WILL STAY NORTH AND EAST OF OUR AREA TONIGHT AS WILL THE LIMITED AREA OF DEEPER SATURATION. WE WILL SEE SOME FORCING AS THE LOW LEVEL TROUGH/WARM FRONT PUSHES EAST ACROSS THE AREA...BUT AT THIS TIME IT LOOKS LIKE WE SHOULD ONLY SEE AN INCREASE IN CLOUD COVER AND NO PCPN AS THIS SWINGS THROUGH. THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN THEIR HANDLING OF SYNOPTIC SCALE FEATURES OVER THE NEXT FEW DAYS...ALTHOUGH THERE ARE SOME MINOR DIFFERENCES IN INTENSITY AND PLACEMENT. IN GENERAL...THE GFS IS A BIT FARTHER SOUTH WITH THE BAROCLINIC ZONE WEDNESDAY NIGHT INTO THURSDAY AND ALLOWS PCPN TO EXTEND SOMEWHAT FARTHER SOUTH THAN THE NAM. IN ADDITION...THE GFS ALSO SATURATES THINGS MORE QUICKLY AND OVER A WIDER AREA THAN THE NAM...AND IS A BIT HIGHER IN ITS PREDICTED PCPN AMOUNTS AS A RESULT. UTILIZED A BLEND OF THE THE GFS AND NAM FOR THE FORECAST DETAILS...TRENDING A BIT MORE TOWARD THE GFS TO ALLOW FOR A BIT MORE PCPN SLIGHTLY FARTHER SOUTH. THERE WILL LIKELY BE A PERIOD OF SOME INCREASED CLOUD COVER FOR A TIME TONIGHT AS AN AREA OF 1000-850MB WARM ADVECTION SLIDES ACROSS THE AREA...THEN WE SHOULD BE BACK TO PARTLY CLOUDY SKIES AWAITING THE MAIN INCREASE IN CLOUD COVER AHEAD OF THE SYSTEM EXPECTED TO MOVE THROUGH WEDNESDAY NIGHT AND THURSDAY. MID/HIGH CLOUDS DESCENDING THE UPPER RIDGE WILL SPREAD ACROSS THE AREA ON WEDNESDAY...THEN THICKEN DURING THE AFTERNOON AS LOW LEVEL RETURN FLOW SETS UP AND WARM ADVECTION INCREASES. THE 290K ISENTROPIC SURFACE SHOWS A DRAMATIC INCREASE IN UPGLIDE BY 00Z THURSDAY...WITH CONDENSATION PRESSURE DEFICITS DROPPING BELOW 50MB OVER MUCH OF THE NORTHERN CWFA. THIS PERSISTS THROUGH 06Z...WITH IMPLIED SATURATION OVER ALL BUT THE FAR SOUTH/SOUTHEAST. GOOD PACKING OF THE PRESSURE SURFACES IS INDICATED...WITH 40KT WINDS AT NEARLY A PERPENDICULAR ANGLE TO THEM...SUGGESTING A GOOD PERIOD OF ISENTROPIC ASCENT. THIS IS MAXIMIZED NORTH AND EAST OF OUR AREA...WHICH IS ALSO WHERE THE BETTER SATURATION IS EXPECTED...BUT THE NORTH AND EAST PORTIONS OF THE FORECAST AREA COULD STILL SEE SEVERAL INCHES OF SNOW WEDNESDAY NIGHT INTO THURSDAY MORNING. MIXING RATIOS OF AROUND 3.5 G/KG ARE PROGGED...BUT WITH ONLY ABOUT A 6-HR WINDOW OF GOOD ISENTROPIC ASCENT EXPECTED...FEEL IT WILL BE TOUGH FOR ANYWHERE IN OUR FORECAST AREA TO SEE MUCH MORE THAN 3.5 INCHES...AND EVEN THAT SHOULD BE CONFINED TO THE NORTH AND EAST. OVER THE SOUTH WHERE SATURATION WILL BE A BIT TOUGHER TO COME BY THERE IS SOME POTENTIAL FOR MIXED PCPN WITH AN ELEVATED WARM LAYER ADVERTISED BY THE NAM AND GFS UNTIL THINGS BECOME SUFFICIENTLY SATURATED. WILL INCLUDE A MENTION OF SOME FZRA EARLY ON TO ACCOUNT FOR THIS POSSIBILITY. THE EASTERN CWFA LOOKS LIKE IT WILL GET SOME ADDITIONAL HELP/SUPPORT FOR A BRIEF TIME THURSDAY MORNING AS FORCING ALONG THE FRONTAL BOUNDARY BRIEFLY CORRESPONDS WITH SOME UPPER DIVERGENCE IN THE EXIT REGION OF THE 110KT 300MB JET THAT WILL BE LOCATED TO OUR SOUTH. WINDS WILL INCREASE QUITE A BIT BEHIND THE FRONT...WITH 925-850MB WINDS OF 35-40KT AND GOOD COLD ADVECTION HELPING TO MIX DOWN A GOOD PORTION OF THAT. WILL INCLUDE THE MENTION OF BLOWING SNOW DURING THE DAY ON THURSDAY AS THESE STRONG WINDS SWING THROUGH THE AREA. SUBSIDENCE LOOKS LIKE IT SHOULD SCOUR OUT MOST OF THE CLOUD COVER THURSDAY NIGHT...THEN RIDGING WILL BUILD ACROSS THE REGION THROUGH FRIDAY NIGHT. && .LONG TERM... IN THE SATURDAY THROUGH TUESDAY TIME FRAME THE MEDIUM RANGE GUIDANCE IS IN REASONABLE AGREEMENT ON THE EVOLUTION OF THE LONGWAVE FEATURES OVER NORTH AMERICA...ALTHOUGH THERE ARE THE EXPECTED DIFFERENCES IN THE TIMING...POSITION...AND AMPLITUDE OF INDIVIDUAL SHORTWAVES. THE HPC PROGS GENERALLY FAVOR THE ECMWF FOR THE DETAILS...AND WILL STICK FAIRLY CLOSE TO THAT IDEA...WITH SOME BLENDING TOWARD THE GOING FORECAST AS WELL AS THE OPERATIONAL GFS AND GFS ENSEMBLE. IN GENERAL...THE LONGWAVE UPPER TROUGH WILL PERSIST OVER EASTERN NORTH AMERICA...WITH RIDGING ALONG THE WEST COAST. A CUTOFF LOW IN THE SOUTHERN STREAM ON SATURDAY WILL PHASE WITH THE EASTERN UPPER TROUGH AS IT BECOME MORE AMPLIFIED BY LATE SUNDAY AND MONDAY AND THEN THE UPPER PATTERN SHOULD PROGRESS SLIGHTLY EASTWARD BY TUESDAY. ALL IN ALL...THIS WILL KEEP GENERALLY DRY NORTHWEST UPPER FLOW OVER OUR AREA THROUGHOUT THIS TIME FRAME. CHANCES FOR PCPN WILL BE DICTATED BY THE PASSAGE OF INDIVIDUAL SHORTWAVES AND FRONTAL FEATURES...WHICH WILL BE DIFFICULT TO NAIL DOWN AT THIS POINT. HOWEVER...GIVEN THE EXPECTED UPPER AIR PATTERN AND ITS GENERALLY DRY AND COOL NATURE...NO SIGNIFICANT WEATHER MAKERS APPEAR IN STORE FOR THE AREA AT THIS POINT. A CLIPPER WILL SCOOT BY TO THE NORTH AND EAST ON SATURDAY...HELPING TO BRING A REINFORCING SHOT OF COLDER TEMPERATURES ALONG WITH SOME CHANCE FOR PCPN. AT THIS POINT THE MAIN ISENTROPIC LIFT AND DPVA LOOK TO BE TO OUR NORTH AND EAST...SO WILL JUST INCLUDE A SLIGHT CHANCE FOR SNOW. IN ADDITION...TEMPERATURES ACTUALLY LOOK MARGINALLY COLD FOR SNOW...WITH SOME WARMER 925-850MB TEMPERATURES TRYING TO SNEAK IN AHEAD OF THE SHORTWAVE. GIVEN THE LOW OVERALL PROBABILITY OF PCPN...WILL ONLY MENTION SNOW AT THIS POINT...ALTHOUGH IF THERE IS ANY PCPN THERE IS SOME CHANCE THAT IT COULD BE MIXED OVER THE SOUTH. ANY FORCING AND MOISTURE WITH THIS SYSTEM SHOULD SHIFT EAST BY SUNDAY...THEN HIGH PRESSURE LOOKS LIKE IT WILL SETTLE IN ACROSS THE REGION THROUGH TUESDAY...SO WILL GO WITH A DRY FORECAST FOR SUNDAY THROUGH TUESDAY AT THIS POINT. && .AVIATION...FOR 18Z AVIATION DISCUSSION AREA OF LOW END VFR AND MVFR CEILINGS IN THE VICINITY OF THE SURFACE RIDGE WILL CONTINUE MOVING EAST/SOUTH OF TAF SITES AND SHRINKING THIS AFTERNOON. A PERIOD OF MOSTLY CLEAR SKIES WILL OCCUR THIS AFTERNOON AT KHON/KFSD/KSUX...BEFORE THE AREA OF MID LEVEL CLOUDS OVER THE WESTERN DAKOTAS ARRIVES LATE THIS AFTERNOON AND EVENING. PREVALENT LIGHT WEST/SOUTHWEST SURFACE WINDS WILL SHIFT TO THE SOUTHEAST AND INCREASE ON WEDNESDAY MORNING...AHEAD OF AN APPROACHING TROUGH OF LOW PRESSURE. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$ 99/99 sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1030 AM CST TUE FEB 12 2008 .UPDATE... MAIN UPDATE FOCUS IS MAX TEMPERATURES TODAY...WHICH IS NOT GOING TO BE AN EASY FORECAST. FOR JAMES VALLEY EAST...LOW CLOUDS RAPIDLY ERODING WITH TEMPERATURES ALREADY IN THE UPPER SINGLE DIGITS THANKS TO UNFAVORABLE RADIATIONAL CONDITIONS OVERNIGHT. WILL SEE LIGHT SOUTHWEST FLOW DEVELOP AS WELL. UNSURE HOW WELL LIGHT WINDS AND A MID FEBRUARY SUN WILL CONSPIRE TO WARM TEMPERATURES...HOWEVER WILL TREND TOWARDS LOWER END OF GUIDANCE WHICH ALLOWS FOR A WARMING INTO THE TEENS BUT BELOW 20. THERE IS ALSO THE QUESTION OF IMPACT FROM INCREASED CLOUDS LATE TODAY AS WEAK TROUGH PASSES THOUGH THE REGION. WINDS WILL SWITCH TO THE NORTH/NORTHWEST WITH BETTER MIXING POTENTIAL OF H925 TEMPERATURES BETWEEN -4 TO -8C...THEREFORE MAXIMUM TEMPERATURE MAY OCCUR DURING TROUGH PASSAGE OR TEMPERATURES MAY REMAIN FAIRLY LEVEL THROUGH THE EVENING. FOR CENTRAL AND NORTH CENTRAL SD...WITH A COLD START DUE TO FAVORABLE RADIATIVE CONDITIONS OVERNIGHT...TEMPERATURES CURRENTLY BELOW ZERO...WITH TEENS TO THE WEST. WINDS SWITCHING TO WESTERLY...BUT REMAIN LIGHT. ALSO CONTENDING WITH INCREASING CLOUD COVER THROUGHOUT THE DAY. A COMBINATION OF WEAK WARM AIR ADVECTION AND MIXING WITH TROUGH PASSAGE COULD ALLOW TEMPERATURES TO RISE INTO THE 20S. FOCUS THEN SHIFTS TOWARDS POTENTIAL IMPACT FROM STORM SYSTEM WEDNESDAY/THURSDAY...HAVE NOT MADE ANY ADJUSTMENTS AT THIS TIME BUT WILL BE MAIN FOCUS FOR AFTERNOON DISCUSSION. AVIATION FORECAST UPDATED BELOW. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH THURSDAY MAIN UPPER LOW AND SFC TROUGH HAS PASSED THE AREA TO THE SOUTHEAST BUT SECONDARY WEAK VORT MAX SHOWN ON RUC ANALYSIS BRINGING ISO/SCT FLURRIES TO PORTIONS OF THE NORTHEASTERN CWA. HAVE THEREFORE ADDED SCT FLURRIES UP THROUGH 12Z AND BY THIS TIME VORT MAX WILL BE MOVING OUT OF THE AREA. ANOTHER WEAK DISTURBANCE SLIDING SOUTHEAST OUT OF EASTERN MT AND EASTERN WY...READY TO MOVE INTO WESTERN SD. MODEL QPF OUTPUT AS WELL AS BUFKIT SOUNDINGS SUGGEST POSSIBILITY FOR A FEW FLURRIES ACROSS THE AREA...BUT BEST CHANCES FOR PRECIP SHOULD BE TO THE NORTH AND TO THE SOUTH...LEAVING THE CWA IN A VOID OF BETTER PRECIP CHANCES. HIGH TEMPS TODAY RATHER TRICKY AND STUCK CLOSE TO MAV GUIDANCE. THERMAL RIDGE BUILDS IN ACROSS THE AREA TODAY BUT FRESH 1 TO 4 INCH SNOW FROM YESTERDAY WILL MORE THAN LIKELY KEEP TEMPS FROM RISING TO FULL POTENTIAL. MAIN ISSUE IN THE SHORT TERM CONTINUES TO BE THE STORM SYSTEM SET TO AFFECT THE AREA WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. NAM SEEMS TO BE AN OUTLIER WITH THIS SYSTEM AND IS NOTICEABLY FARTHER NORTH WITH THE LOW TRACK COMPARED TO OTHER MODELS. MODEL QPF OUTPUT ALONG WITH HPC GUIDANCE HIT THE NORTHEASTERN CWA HARDEST WITH ABOUT 3 TO 6 INCHES OF SNOW...AND THIS SEEMS LIKELY GIVEN THE FORCING/FRONTOGENESIS AND SNOW RATIOS. BUFKIT SNOW GROWTH REGION FOR ABR LINES UP WELL WITH OMEGA BULLSEYE. COULD BE LOOKING AT SNOW ADVISORY TYPE EVENT ACROSS THE NORTHEAST BUT WILL LET LATER SHIFTS DECIDE ON ANY POSSIBLE HEADLINES AS IT APPEARS WINDS WILL BE AN ISSUE BEHIND THE SYSTEM. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY PCPN AND TEMPERATURES REMAIN A CHALLENGE. 00Z MODELS ARE IN FAIR AGREEMENT ON THE LONG WAVE/SYNOPTIC SCALE MID LEVEL FLOW PATTERN THROUGH THE MEDIUM RANGE. AS SUCH...ALL ARE ADVERTISING A HIGHLY AMPLIFIED/HIGHLY MERIDIONAL FLOW DEVELOPING AS MID LEVEL RIDGE BUILDS STRONGLY ALONG WEST COAST...WITH CONSEQUENT DOWNSTREAM TROF OVER CENTRAL/EASTERN CONUS. ABOUT THE ONLY SUBSTANTIVE DIFFERENCE IN THE LONG WAVE PATTERN BETWEEN THE MODELS IS THAT THE ECMWF REMAINS CONSISTENT IN KEEPING THE CENTRAL/EASTERN CONUS TROF AXIS ANCHORED FURTHER WEST VS THE GFS. IF CORRECT...THIS COULD PLAY OUT AS COLDER TEMPERATURES EARLY NEXT WEEK. SOMETHING FOR LATER SHIFTS TO PONDER. MEANWHILE THE BEST CHANCE FOR MEASURABLE PCPN DURING THE TIME PERIOD APPEARS TO BE SATURDAY/SATURDAY NIGHT. BOTH ECMWF/GFS SCOOT A CLIPPER-LIKE WAVE ACROSS THE REGION WITH THE ECMWF BEING SOMEWHAT STRONGER THAN THE GFS. DUE TO UNCERTAINTY WITH STRENGTH OF THE SYSTEM...FEEL CURRENT ISOLD POPS ARE APPROPRIATE. TEMPERATURES WERE MODIFIED A BIT HERE AND THERE. THE MAJORITY OF CHANGES WERE FOR FRIDAY NIGHT/SATURDAY WHERE I RAISED THEM A TOUCH BASED OFF LATEST GFS/ECMWF LOWER TROPOSPHERIC TEMP PROGS. && .AVIATION... WILL CONTINUE TO SEE GRADUAL CLEARING TREND AT KABR AND KATY OVER THE NEXT FEW HOURS WHILE MID AND HIGH CLOUDS WILL BE ON THE INCREASE FOR KMBG AND KPIR DURING THE AFTERNOON. VISBY WILL REMAIN UNRESTRICTED ACROSS THE CWA TODAY AND TONIGHT. AVIATION FORECAST A BIT TRICKY EARLY TOMORROW WITH INCREASING CLOUDS AHEAD OF OUR NEXT WEATHER SYSTEM. CIGS WILL REMAIN MAINLY VFR WITH AREAS OF MVFR AROUND KPIR...WHILE KMBG...KABY...KABR WILL SEE CIGS TURN MVFR BETWEEN 06 AND 12Z. SNOW IS EXPECTED TO DEVELOP AFTER 12Z BUT VISBY RESTRICTIONS ONLY EXPECTED AT KABR/KMBG AT THIS TIME. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...CONNELLY SHORT TERM...TMT LONG TERM...TDK AVIATION...TDK WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 410 AM CST TUE FEB 12 2008 .SHORT TERM...TODAY THROUGH THURSDAY MAIN UPPER LOW AND SFC TROUGH HAS PASSED THE AREA TO THE SOUTHEAST BUT SECONDARY WEAK VORT MAX SHOWN ON RUC ANALYSIS BRINGING ISO/SCT FLURRIES TO PORTIONS OF THE NORTHEASTERN CWA. HAVE THEREFORE ADDED SCT FLURRIES UP THROUGH 12Z AND BY THIS TIME VORT MAX WILL BE MOVING OUT OF THE AREA. ANOTHER WEAK DISTURBANCE SLIDING SOUTHEAST OUT OF EASTERN MT AND EASTERN WY...READY TO MOVE INTO WESTERN SD. MODEL QPF OUTPUT AS WELL AS BUFKIT SOUNDINGS SUGGEST POSSIBILITY FOR A FEW FLURRIES ACROSS THE AREA...BUT BEST CHANCES FOR PRECIP SHOULD BE TO THE NORTH AND TO THE SOUTH...LEAVING THE CWA IN A VOID OF BETTER PRECIP CHANCES. HIGH TEMPS TODAY RATHER TRICKY AND STUCK CLOSE TO MAV GUIDANCE. THERMAL RIDGE BUILDS IN ACROSS THE AREA TODAY BUT FRESH 1 TO 4 INCH SNOW FROM YESTERDAY WILL MORE THAN LIKELY KEEP TEMPS FROM RISING TO FULL POTENTIAL. MAIN ISSUE IN THE SHORT TERM CONTINUES TO BE THE STORM SYSTEM SET TO AFFECT THE AREA WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING. NAM SEEMS TO BE AN OUTLIER WITH THIS SYSTEM AND IS NOTICEABLY FARTHER NORTH WITH THE LOW TRACK COMPARED TO OTHER MODELS. MODEL QPF OUTPUT ALONG WITH HPC GUIDANCE HIT THE NORTHEASTERN CWA HARDEST WITH ABOUT 3 TO 6 INCHES OF SNOW...AND THIS SEEMS LIKELY GIVEN THE FORCING/FRONTOGENESIS AND SNOW RATIOS. THE QUESTION REMAINS THOUGH AS TO WHERE THIS HEAVIER BAND SETS UP. BUFKIT SNOW GROWTH REGION FOR ABR LINES UP WELL WITH OMEGA BULLSEYE. COULD BE LOOKING AT SNOW ADVISORY TYPE EVENT ACROSS THE NORTHEAST BUT WILL LET LATER SHIFTS DECIDE ON ANY POSSIBLE HEADLINES AS IT APPEARS WINDS WILL BE AN ISSUE BEHIND THE SYSTEM. ALSO DECIDED TO HOLD OFF ON HEADLINES AFTER GLANCING QUICK AT THE 06Z GFS WHICH NOW SHIFTS THE LOW TRACK A TAD FARTHER NORTH...BRINGING HEAVIEST SNOWS FARTHER NORTH AND EAST INTO EASTERN NORTH DAKOTA AND MINNESOTA. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY PCPN AND TEMPERATURES REMAIN A CHALLENGE. 00Z MODELS ARE IN FAIR AGREEMENT ON THE LONG WAVE/SYNOPTIC SCALE MID LEVEL FLOW PATTERN THROUGH THE MEDIUM RANGE. AS SUCH...ALL ARE ADVERTISING A HIGHLY AMPLIFIED/HIGHLY MERIDIONAL FLOW DEVELOPING AS MID LEVEL RIDGE BUILDS STRONGLY ALONG WEST COAST...WITH CONSEQUENT DOWNSTREAM TROF OVER CENTRAL/EASTERN CONUS. ABOUT THE ONLY SUBSTANTIVE DIFFERENCE IN THE LONG WAVE PATTERN BETWEEN THE MODELS IS THAT THE ECMWF REMAINS CONSISTENT IN KEEPING THE CENTRAL/EASTERN CONUS TROF AXIS ANCHORED FURTHER WEST VS THE GFS. IF CORRECT...THIS COULD PLAY OUT AS COLDER TEMPERATURES EARLY NEXT WEEK. SOMETHING FOR LATER SHIFTS TO PONDER. MEANWHILE THE BEST CHANCE FOR MEASURABLE PCPN DURING THE TIME PERIOD APPEARS TO BE SATURDAY/SATURDAY NIGHT. BOTH ECMWF/GFS SCOOT A CLIPPER-LIKE WAVE ACROSS THE REGION WITH THE ECMWF BEING SOMEWHAT STRONGER THAN THE GFS. DUE TO UNCERTAINTY WITH STRENGTH OF THE SYSTEM...FEEL CURRENT ISOLD POPS ARE APPROPRIATE. TEMPERATURES WERE MODIFIED A BIT HERE AND THERE. THE MAJORITY OF CHANGES WERE FOR FRIDAY NIGHT/SATURDAY WHERE I RAISED THEM A TOUCH BASED OFF LATEST GFS/ECMWF LOWER TROPOSPHERIC TEMP PROGS. && .AVIATION... OVERALL THE MVFR/VFR CIGS SHOULD GRADUALLY ERODE/DISSIPATE OVER THE AREA THIS MORNING. HOWEVER...MORE MVFR CIGS AROUND 15-25 HUNDRED FEET ARE EXPECTED TO OVERSPREAD KMBG/KPIR TERMINALS THIS AFTERNOON. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...TMT LONG TERM...TDK AVIATION...TDK WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 835 PM CST MON FEB 11 2008 .UPDATE... RADAR INDICATING SOME NEW LIGHT SNOW DEVELOPMENT ACROSS FAR SOUTHEASTERN NORTH DAKOTA...AND THE AREA IS DRIFTING SOUTH/SOUTHEAST...SO HAVE REINTRODUCED A CHANCE FOR SOME LIGHT SNOW ACROSS THE EASTERN CWA THROUGH ABOUT MIDNIGHT. ALSO LOWERED TEMPS A BIT MORE FOR TONIGHT OUT WEST AS CLEARING LINE HAS REACHED THE WESTERN PORTION OF CORSON COUNTY. NO OTHER CHANGES MADE AT THIS TIME. NEW AVIATION DISCUSSION BELOW. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT FOCUS THIS PERIOD IS ON NEAR TERM AS HEAVY SNOW CONTINUES IN A BAND FROM SOUTH OF KABR TO NORTH OF KPIR. THIS FEATURE HAS SLOWLY DRIFTED SOUTHWARD FROM NORTH CENTRAL SD THROUGHOUT THE DAY AND HAS PRODUCED A SWATH OF 2 INCH SNOWFALL. SUPPORT FOR CONTINUED HEAVY SNOWFALL TO DIMINISH AND DRIFT SOUTHWARDS. WILL CONTINUE SNOW ADVISORY INTO THE EARLY EVENING WITH ANTICIPATION THAT ACCUMULATING SNOWFALL WILL HAVE CEASED BY THAT POINT. GFS/RUC SUGGEST LIMITED CLEARING OF LOW CLOUDS TONIGHT AS AMORPHOUS HIGH PRESSURE BUILDS OVER REGION. CANT RULE OUT INTERMITTENT CLEARING...MAINLY IN OUR CENTRAL COUNTIES...BUT FIND IT CLIMATOLOGICALLY UNLIKELY IN THE JAMES/RED RIVER VALLEYS WITH LACK OF STRONG DRY OR COLD AIR ADVECTION. THUS WILL LIMIT TEMPERATURE DROP OVERNIGHT. TEMPERATURES TOMORROW WILL SEE LIMITED RISE FROM JAMES VALLEY EAST EARLY DUE TO CONTINUED CLOUDS AND LIGHT WINDS DESPITE A WARM AIR ADVECTION REGIME DEVELOPING ALOFT. IN OUR CENTRAL COUNTIES WARMING TREND WILL BE MORE PRONOUNCED DESPITE RECENT SNOW COVER. CURIOUS FEATURE DEVELOPS ON THE 290 THETA E SURFACE TOMORROW AHEAD OF A WEAK SURFACE TROUGH. MAIN SUPPORT FOR ACCUMULATING SNOWFALL WELL TO THE NORTHEAST IN MN/ND WITH SHORTWAVE OVER WESTERN ONTARIO...HOWEVER SINCE WE ARE UNABLE TO SCOUR OUT LOW LEVEL CLOUDS/MOISTURE CANT RULE OUT LIGHT SNOW BUT NEED TO REITERATE THAT EVEN MINIMAL ACCUMULATION IS UNLIKELY. MORE IMPORTANTLY...WESTERLY WINDS BEHIND TROUGH WILL HELP MIX OUT COLD AIR IN THE JAMES VALLEY LATE IN THE DAY. THEREFORE HAVE TRENDED A FEW DEGREES ABOVE GUIDANCE FOR TOMORROWS HIGH. .LONG TERM...WEDNESDAY THROUGH MONDAY FORECAST CHALLENGES...SNOW WEDNESDAY THROUGH THURSDAY MORNING AND TEMPERATURES THURSDAY AND FRIDAY. THE ACTIVE PATTERN CONTINUES. THE LOW PRESSURE SYSTEM FOR MID WEEK STILL APPEARS ON TRACK TO DROP SEVERAL INCHES OF SNOW OVER THE CWA...PERHAPS MORE SO ACROSS THE NE CORNER OF THE CWA. BEHIND THE SYSTEM...STRONG WINDS AND STRONG CAA /AS HIGH PRESSURE BUILDS IN/ WILL CREATE BLOWING SNOW AND WIND CHILL PROBLEMS. THE COLD AIR SITS AROUND THURSDAY AND FRIDAY BEFORE A WARM UP DEVELOPS FRIDAY NIGHT AND SATURDAY. ANOTHER BROAD UPPER TROF WILL SWEEP THROUGH SATURDAY AND SUNDAY...BUT THIS SYSTEM IS EXPECTED TO GENERATE MAINLY FLURRIES AND SOME LOW CLOUD COVER FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION... LIGHT SNOW NOW EXITING THE SOUTHERN CWA...BUT AN AREA OF NEW DEVELOPMENT NOW APPROACHING THE NORTHEASTERN CWA. WILL SEE OVC CIGS BETWEEN 2500-5000 FEET MOST AREAS...WITH CLEARING TAKING PLACE ACROSS THE FAR WESTERN CWA NOW. EXPECT THE CLEARING TO CONTINUE EASTWARD OVERNIGHT...BUT ANOTHER AREA OF CLOUDS AOA 8K FEET WILL SPREAD FROM WEST TO EAST BEGINNING AROUND 08Z. THEREFORE...ANY ONE LOCATION WILL LIKELY SEE THE MOSTLY CLEAR SKIES FOR 3 TO 6 HOURS BEFORE THE NEXT DECK OF CLOUDS MOVES IN. VSBYS WILL BE UNRESTRICTED...BUT MAY FALL TO AROUND 4SM IN THE SNOW AREAS. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...PARKIN SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...PARKIN WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 620 PM CST MON FEB 11 2008 .UPDATE... UPDATED DUE TO EXPIRATION OF SNOW ADVISORY ACROSS THE SOUTHWESTERN AND SOUTH CENTRAL CWA. ALSO LOWERED TEMPS FOR TONIGHT ACROSS THE WEST IN ANTICIPATION OF A PERIOD OF CLEARING LATER TONIGHT. NEW AVIATION DISCUSSION BELOW. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT FOCUS THIS PERIOD IS ON NEAR TERM AS HEAVY SNOW CONTINUES IN A BAND FROM SOUTH OF KABR TO NORTH OF KPIR. THIS FEATURE HAS SLOWLY DRIFTED SOUTHWARD FROM NORTH CENTRAL SD THROUGHOUT THE DAY AND HAS PRODUCED A SWATH OF 2 INCH SNOWFALL. SUPPORT FOR CONTINUED HEAVY SNOWFALL TO DIMINISH AND DRIFT SOUTHWARDS. WILL CONTINUE SNOW ADVISORY INTO THE EARLY EVENING WITH ANTICIPATION THAT ACCUMULATING SNOWFALL WILL HAVE CEASED BY THAT POINT. GFS/RUC SUGGEST LIMITED CLEARING OF LOW CLOUDS TONIGHT AS AMORPHOUS HIGH PRESSURE BUILDS OVER REGION. CANT RULE OUT INTERMITTENT CLEARING...MAINLY IN OUR CENTRAL COUNTIES...BUT FIND IT CLIMATOLOGICALLY UNLIKELY IN THE JAMES/RED RIVER VALLEYS WITH LACK OF STRONG DRY OR COLD AIR ADVECTION. THUS WILL LIMIT TEMPERATURE DROP OVERNIGHT. TEMPERATURES TOMORROW WILL SEE LIMITED RISE FROM JAMES VALLEY EAST EARLY DUE TO CONTINUED CLOUDS AND LIGHT WINDS DESPITE A WARM AIR ADVECTION REGIME DEVELOPING ALOFT. IN OUR CENTRAL COUNTIES WARMING TREND WILL BE MORE PRONOUNCED DESPITE RECENT SNOW COVER. CURIOUS FEATURE DEVELOPS ON THE 290 THETA E SURFACE TOMORROW AHEAD OF A WEAK SURFACE TROUGH. MAIN SUPPORT FOR ACCUMULATING SNOWFALL WELL TO THE NORTHEAST IN MN/ND WITH SHORTWAVE OVER WESTERN ONTARIO...HOWEVER SINCE WE ARE UNABLE TO SCOUR OUT LOW LEVEL CLOUDS/MOISTURE CANT RULE OUT LIGHT SNOW BUT NEED TO REITERATE THAT EVEN MINIMAL ACCUMULATION IS UNLIKELY. MORE IMPORTANTLY...WESTERLY WINDS BEHIND TROUGH WILL HELP MIX OUT COLD AIR IN THE JAMES VALLEY LATE IN THE DAY. THEREFORE HAVE TRENDED A FEW DEGREES ABOVE GUIDANCE FOR TOMORROWS HIGH. .LONG TERM...WEDNESDAY THROUGH MONDAY FORECAST CHALLENGES...SNOW WEDNESDAY THROUGH THURSDAY MORNING AND TEMPERATURES THURSDAY AND FRIDAY. THE ACTIVE PATTERN CONTINUES. THE LOW PRESSURE SYSTEM FOR MID WEEK STILL APPEARS ON TRACK TO DROP SEVERAL INCHES OF SNOW OVER THE CWA...PERHAPS MORE SO ACROSS THE NE CORNER OF THE CWA. BEHIND THE SYSTEM...STRONG WINDS AND STRONG CAA /AS HIGH PRESSURE BUILDS IN/ WILL CREATE BLOWING SNOW AND WIND CHILL PROBLEMS. THE COLD AIR SITS AROUND THURSDAY AND FRIDAY BEFORE A WARM UP DEVELOPS FRIDAY NIGHT AND SATURDAY. ANOTHER BROAD UPPER TROF WILL SWEEP THROUGH SATURDAY AND SUNDAY...BUT THIS SYSTEM IS EXPECTED TO GENERATE MAINLY FLURRIES AND SOME LOW CLOUD COVER FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION... LIGHT SNOW WILL CONTINUE THROUGH ABOUT 02Z ACROSS THE SOUTHERN CWA...MAINLY SOUTH OF A LINE FROM MISSION RIDGE TO WATERTOWN. CIGS WITH THE AREA OF SNOW WILL BE IN THE MVFR CATEGORY BETWEEN 2K AND 3K FEET...BUT COULD BRIEFLY DROP INTO THE IFR CATEGORY. THE REST OF THE AREA WILL SEE VFR CIGS BETWEEN 3500-6000 FEET. THE CWA MAY SEE SOME CLEARING FROM WEST TO EAST BEGINNING AROUND 06Z...WITH VFR CIGS AOA 8K FEET MOVING BACK IN BY MORNING. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...PARKIN SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...PARKIN WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 529 PM CST MON FEB 11 2008 .UPDATE... UPDATED TO CANCEL SNOW ADVISORY IN NORTH CENTRAL ZONES. && .PREV DISCUSSION... .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT FOCUS THIS PERIOD IS ON NEAR TERM AS HEAVY SNOW CONTINUES IN A BAND FROM SOUTH OF KABR TO NORTH OF KPIR. THIS FEATURE HAS SLOWLY DRIFTED SOUTHWARD FROM NORTH CENTRAL SD THROUGHOUT THE DAY AND HAS PRODUCED A SWATH OF 2 INCH SNOWFALL. SUPPORT FOR CONTINUED HEAVY SNOWFALL TO DIMINISH AND DRIFT SOUTHWARDS. WILL CONTINUE SNOW ADVISORY INTO THE EARLY EVENING WITH ANTICIPATION THAT ACCUMULATING SNOWFALL WILL HAVE CEASED BY THAT POINT. GFS/RUC SUGGEST LIMITED CLEARING OF LOW CLOUDS TONIGHT AS AMORPHOUS HIGH PRESSURE BUILDS OVER REGION. CANT RULE OUT INTERMITTENT CLEARING...MAINLY IN OUR CENTRAL COUNTIES...BUT FIND IT CLIMATOLOGICALLY UNLIKELY IN THE JAMES/RED RIVER VALLEYS WITH LACK OF STRONG DRY OR COLD AIR ADVECTION. THUS WILL LIMIT TEMPERATURE DROP OVERNIGHT. TEMPERATURES TOMORROW WILL SEE LIMITED RISE FROM JAMES VALLEY EAST EARLY DUE TO CONTINUED CLOUDS AND LIGHT WINDS DESPITE A WARM AIR ADVECTION REGIME DEVELOPING ALOFT. IN OUR CENTRAL COUNTIES WARMING TREND WILL BE MORE PRONOUNCED DESPITE RECENT SNOW COVER. CURIOUS FEATURE DEVELOPS ON THE 290 THETA E SURFACE TOMORROW AHEAD OF A WEAK SURFACE TROUGH. MAIN SUPPORT FOR ACCUMULATING SNOWFALL WELL TO THE NORTHEAST IN MN/ND WITH SHORTWAVE OVER WESTERN ONTARIO...HOWEVER SINCE WE ARE UNABLE TO SCOUR OUT LOW LEVEL CLOUDS/MOISTURE CANT RULE OUT LIGHT SNOW BUT NEED TO REITERATE THAT EVEN MINIMAL ACCUMULATION IS UNLIKELY. MORE IMPORTANTLY...WESTERLY WINDS BEHIND TROUGH WILL HELP MIX OUT COLD AIR IN THE JAMES VALLEY LATE IN THE DAY. THEREFORE HAVE TRENDED A FEW DEGREES ABOVE GUIDANCE FOR TOMORROWS HIGH. .LONG TERM...WEDNESDAY THROUGH MONDAY FORECAST CHALLENGES...SNOW WEDNESDAY THROUGH THURSDAY MORNING AND TEMPERATURES THURSDAY AND FRIDAY. THE ACTIVE PATTERN CONTINUES. THE LOW PRESSURE SYSTEM FOR MID WEEK STILL APPEARS ON TRACK TO DROP SEVERAL INCHES OF SNOW OVER THE CWA...PERHAPS MORE SO ACROSS THE NE CORNER OF THE CWA. BEHIND THE SYSTEM...STRONG WINDS AND STRONG CAA /AS HIGH PRESSURE BUILDS IN/ WILL CREATE BLOWING SNOW AND WIND CHILL PROBLEMS. THE COLD AIR SITS AROUND THURSDAY AND FRIDAY BEFORE A WARM UP DEVELOPS FRIDAY NIGHT AND SATURDAY. ANOTHER BROAD UPPER TROF WILL SWEEP THROUGH SATURDAY AND SUNDAY...BUT THIS SYSTEM IS EXPECTED TO GENERATE MAINLY FLURRIES AND SOME LOW CLOUD COVER FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION... INTERMITTENT LIGHT SNOW WILL CONTINUE THROUGH THE AFTERNOON HOURS WITH A FEW HEAVIER BANDS LOCATED JUST NORTH OF KPIR TO JUST SOUTH OF KABR. MOST LOCATIONS NORTH OF THIS AREA OF INTENSE SNOW WILL SEE MVFR CIGS WITH GRADUAL IMPROVEMENT THIS AFTERNOON AND EVENING. HEAVY SNOW WILL DRIFT SOUTHEAST LATE THIS AFTERNOON AND EVENING...CAUSING SIGNIFICANT REDUCTIONS IN BOTH VSBY/CIGS. AT THIS TIME...THE WORST CONDITIONS APPEAR TO REMAIN WEST OF KATY...BUT WILL CONTINUE AT KPIR...WHICH IS NOT EXPECTED TO IMPROVE MUCH THOUGH 00Z. ONCE THE HEAVY SNOW DRIFTS OUT OF THE CWA...IMPROVEMENTS IN CIGS WILL FOLLOW. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...SNOW ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR BUFFALO-FAULK-HAND-HUGHES-HYDE-JONES-LYMAN-POTTER-SPINK- STANLEY-SULLY. MN...NONE. && $$ UPDATE...PARKIN SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...CONNELLY WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 346 PM CST MON FEB 11 2008 .SHORT TERM...THROUGH WEDNESDAY MORNING. FOCUS THIS PERIOD IS ON NEAR TERM AS HEAVY SNOW CONTINUES IN A BAND FROM SOUTH OF KABR TO NORTH OF KPIR. THIS FEATURE HAS SLOWLY DRIFTED SOUTHWARD FROM NORTH CENTRAL SD THROUGHOUT THE DAY AND HAS PRODUCED A SWATH OF 2 INCH SNOWFALL. SUPPORT FOR CONTINUED HEAVY SNOWFALL TO DIMINISH AND DRIFT SOUTHWARDS. WILL CONTINUE SNOW ADVISORY INTO THE EARLY EVENING WITH ANTICIPATION THAT ACCUMULATING SNOWFALL WILL HAVE CEASED BY THAT POINT. GFS/RUC SUGGEST LIMITED CLEARING OF LOW CLOUDS TONIGHT AS AMORPHOUS HIGH PRESSURE BUILDS OVER REGION. CANT RULE OUT INTERMITTENT CLEARING...MAINLY IN OUR CENTRAL COUNTIES...BUT FIND IT CLIMATOLOGICALLY UNLIKELY IN THE JAMES/RED RIVER VALLEYS WITH LACK OF STRONG DRY OR COLD AIR ADVECTION. THUS WILL LIMIT TEMPERATURE DROP OVERNIGHT. TEMPERATURES TOMORROW WILL SEE LIMITED RISE FROM JAMES VALLEY EAST EARLY DUE TO CONTINUED CLOUDS AND LIGHT WINDS DESPITE A WARM AIR ADVECTION REGIME DEVELOPING ALOFT. IN OUR CENTRAL COUNTIES WARMING TREND WILL BE MORE PRONOUNCED DESPITE RECENT SNOW COVER. CURIOUS FEATURE DEVELOPS ON THE 290 THETA E SURFACE TOMORROW AHEAD OF A WEAK SURFACE TROUGH. MAIN SUPPORT FOR ACCUMULATING SNOWFALL WELL TO THE NORTHEAST IN MN/ND WITH SHORTWAVE OVER WESTERN ONTARIO...HOWEVER SINCE WE ARE UNABLE TO SCOUR OUT LOW LEVEL CLOUDS/MOISTURE CANT RULE OUT LIGHT SNOW BUT NEED TO REITERATE THAT EVEN MINIMAL ACCUMULATION IS UNLIKELY. MORE IMPORTANTLY...WESTERLY WINDS BEHIND TROUGH WILL HELP MIX OUT COLD AIR IN THE JAMES VALLEY LATE IN THE DAY. THEREFORE HAVE TRENDED A FEW DEGREES ABOVE GUIDANCE FOR TOMORROWS HIGH. .LONG TERM...WEDNESDAY THROUGH MONDAY FORECAST CHALLENGES...SNOW WEDNESDAY THROUGH THURSDAY MORNING AND TEMPERATURES THURSDAY AND FRIDAY. THE ACTIVE PATTERN CONTINUES. THE LOW PRESSURE SYSTEM FOR MID WEEK STILL APPEARS ON TRACK TO DROP SEVERAL INCHES OF SNOW OVER THE CWA...PERHAPS MORE SO ACROSS THE NE CORNER OF THE CWA. BEHIND THE SYSTEM...STRONG WINDS AND STRONG CAA /AS HIGH PRESSURE BUILDS IN/ WILL CREATE BLOWING SNOW AND WIND CHILL PROBLEMS. THE COLD AIR SITS AROUND THURSDAY AND FRIDAY BEFORE A WARM UP DEVELOPS FRIDAY NIGHT AND SATURDAY. ANOTHER BROAD UPPER TROF WILL SWEEP THROUGH SATURDAY AND SUNDAY...BUT THIS SYSTEM IS EXPECTED TO GENERATE MAINLY FLURRIES AND SOME LOW CLOUD COVER FOR THE WEEKEND INTO EARLY NEXT WEEK. && .AVIATION... INTERMITTENT LIGHT SNOW WILL CONTINUE THROUGH THE AFTERNOON HOURS WITH A FEW HEAVIER BANDS LOCATED JUST NORTH OF KPIR TO JUST SOUTH OF KABR. MOST LOCATIONS NORTH OF THIS AREA OF INTENSE SNOW WILL SEE MVFR CIGS WITH GRADUAL IMPROVEMENT THIS AFTERNOON AND EVENING. HEAVY SNOW WILL DRIFT SOUTHEAST LATE THIS AFTERNOON AND EVENING...CAUSING SIGNIFICANT REDUCTIONS IN BOTH VISBY/CIGS. AT THIS TIME...THE WORST CONDITIONS APPEAR TO REMAIN WEST OF KATY...BUT WILL CONTINUE AT KPIR...WHICH IS NOT EXPECTED TO IMPROVE MUCH THOUGH 00Z. ONCE THE HEAVY SNOW DRIFTS OUT OF THE CWA...IMPROVEMENTS IN CIGS WILL FOLLOW. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...SNOW ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR BUFFALO-CAMPBELL-CORSON-DEWEY-EDMUNDS-FAULK-HAND-HUGHES- HYDE-JONES-LYMAN-MCPHERSON-POTTER-SPINK-STANLEY-SULLY- WALWORTH. MN...NONE. && $$ SHORT TERM...CONNELLY LONG TERM...DORN AVIATION...CONNELLY WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 937 AM CST MON FEB 11 2008 .UPDATE... INHERITED FORECAST THIS MORNING IS SPOT ON SO NOT MUCH TO DISCUSS IN THE UPDATE. MESO FEATURE MOVING FROM THE BLACK HILLS INTO CENTRAL SD. ADDITIONAL 2 INCHES REPORTED AT FAITH...WHICH SUPPORTS GOING FORECAST OF UPWARDS OF 3 INCHES FROM SULLY CO SOUTH TO THE WHITE RIVER. RUC PICKS UP FEATURE IN H7 OMEGA FIELD...ALTHOUGH A LITTLE FAST IN PROPAGATION SPEED...AND MOVES IT INTO FSD CWA BY BETWEEN 18 AND 21Z. SECOND AREA OF NOTE IS NEAR KMBG...WHICH RUC ALSO IDENTIFIES...SENDING IT ON A SOUTHEAST TRAJECTORY ACROSS THE EAST CENTRAL CW...ROUGHLY FROM KMBG TO KHON. WATER PLANT AT KMBG HAS REPORTED ADDITIONAL HALF INCH BY 930AM...THOUGH SNOW STILL REMAINS HEAVY AT THIS TIME. THINKING 1 TO 2 INCH ACCUMULATION WITH THIS FEATURE POSSIBLE. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH WEDNESDAY MODELS AGREE PRETTY WELL ON THIS PERIOD. CONCERNS THIS TIME ARE WIND CHILL TEMPERATURES AND SNOW FALL AMOUNTS. AT THIS TIME THE LOW PRESSURE SYSTEM WITH THE STRONG COLD FRONT HAS MOVED EAST. THE SURFACE HIGH PRESSURE SYSTEM THAT FOLLOWED IT IN AND PRODUCED THE STRONG NORTHWEST WINDS HAS MOVED INTO MINNESOTA. THE NEXT CLIPPER SYSTEM IS IN MONTANA WITH A TROUGH EXTENDING SOUTH INTO WESTERN SOUTH DAKOTA. A FAIRLY STRONG PRESSURE GRADIENT HAS DEVELOPED BETWEEN THE RETREATING HIGH AND THE ADVANCING LOW PRESSURE SYSTEM. THIS STRONG GRADIENT IS ALLOWING STRONG SOUTHEAST WIND TO BING WARMER AND MORE MOIST AIR INTO THE REGION. SEVERAL LOCATIONS IN EASTERN SOUTH DAKOTA AND WEST CENTRAL MINNESOTA ARE REPORTING SNOW AS WARM AIR OVER RUNS COLD ARCTIC SURFACE AIR. THIS WIND WILL CONTINUE FOR MUCH OF THE MORNING BEFORE WINDS BECOME MORE EASTERLY AND DIMINISH. AS THE SURFACE LOW TRACKS SOUTH IT WILL REMAIN WEST OF HERE. AN OLD BAROCLINIC ZONE IS STILL LINGERING IN THE AREA AND WILL END UP ORIENTED EAST WEST IN CENTRAL SOUTH DAKOTA BY THIS AFTERNOON. AT THIS SAME TIME A SHARP H5 TROUGH PUSHES ACROSS THE REGION AND FINALLY DRAWS OFF TO THE EAST BY TOMORROW MORNING. IT APPEARS THAT THIS SYSTEM WILL BE ABLE TO DRAW MOISTURE UP FROM THE SOUTH AND WITH THE HELP OF THE OLD BAROCLINIC ZONE WILL BE ABLE TO DROP SOME PRETTY GOOD SNOW. ESPECIALLY IN THE SOUTH CENTRAL PART OF THE STATE THE BUF KIT SOUNDINGS SUGGEST SATURATED AIR THROUGH THE DENDRITIC LAYER AND VERY PRONOUNCED LIFT FOR SEVERAL HOURS DURING THIS PERIOD. GFS ALSO CONTINUES TO SHOW GOOD FRONTOGENETIC FORCING IN THE SAME GENERAL AREA. SO WITH THIS HAVE MADE FEW CHANGES TO GOING GRIDS WHICH ADVERTISE ADVISORY SNOWFALL TODAY. ALSO THE COMBINATION OF LOW TEMPERATURES AND STRONG SOUTH WINDS WILL PRODUCE WIND CHILL READING BELOW -20F. SO WILL CONTINUE THE WINTER WEATHER ADVISORY THROUGH TODAY FOR WIND CHILLS ESPECIALLY THIS MORNING AND SNOWFALL AMOUNTS OF TWO TO FOUR INCHES. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY PCPN CHANCES AND TEMPS ARE THE MAIN FORECAST QUANDARIES. 00Z MODEL RUNS REMAIN QUITE SIMILAR WITH OVERALL MID LEVEL FLOW PATTERN THROUGH THE PERIOD. ONCE AGAIN ENERGY IS EXPECTED TO COME ASHORE NEAR THE PACIFIC NORTHWEST AND THEN DIVE SOUTHEAST AND AMPLIFY OVER THE CENTRAL CONUS. TWO SUCH SYSTEMS LOOK TO PLAY OUT DURING THIS TIME PERIOD. ONE FOR WEDNESDAY NIGHT INTO THURSDAY...AND ANOTHER FOR THE COMING WEEKEND. UNLIKE TODAYS SYSTEM...THE TRACK OF THE SURFACE LOW FOR WEDNESDAY NIGHT INTO THURSDAY SUGGESTS THAT THE BEST POTENTIAL FOR SIGNIFICANT SNOW WILL BE OVER NORTH DAKOTA AND MINNESOTA. THIS IS ALSO DISPLAYED SIMILARLY IN THE QPF FIELDS FROM BOTH GFS/ECMWF. BEHIND THE SYSTEM COLD AIR ONCE AGAIN FILTERS SOUTH OVER THE REGION. HOWEVER...THE LATEST MODEL RUNS ARE NOT QUITE AS COLD AS PREVIOUS RUNS. BUT...FOR THE MOST PART ONLY MADE MINOR CHANGES TO THE TEMPERATURE GRIDS. IT APPEARS THAT THE RECENTLY PROGRESSIVE MID LEVEL PATTERN MAY SLOW UP TOWARD THE END OF THE PERIOD AND BECOME MORE MERIDIONAL AS A POSITIVE PNA PATTERN TAKES SHAPE OVER THE CONUS. THIS PATTERN WILL LIKELY BRING MORE COLD AIR INTO THE CENTRAL AND EASTERN CONUS AFTER 168 HOURS. && .AVIATION... INTERMITTENT LIGHT SNOW WILL CONTINUE THROUGH THE LATE MORNING HOURS WITH A HEAVIER BAND OF SNOWFALL OVER AND SOUTH OF KPIR. THIS IS RESULTING IN MAINLY MVFR CIGS WITH INTERMITTENT IFR UNDER POCKETS OF SNOW...WHICH WILL GRADUALLY IMPROVE THIS EVENING. VISBY WILL FOLLOW THE SAME TREND W/ EXCEPTION TO POINTS ALONG AND SOUTH OF A KPIR TO KHON LINE WHERE IFR VISBY WILL BE MORE COMMON DUE TO A LOCALIZED AREA OF HEAVY SNOWS. THIS FEATURE WILL CONTINUE SOUTHEAST AND DEPART THE CWA BY MID AFTERNOON. SECOND AREA OF HEAVY SNOW WILL MOVE SOUTH OF KMBG BY NOON. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS AFTERNOON FOR BROWN-BUFFALO-CAMPBELL-CLARK-CODINGTON-CORSON-DAY-DEUEL- DEWEY-EDMUNDS-FAULK-GRANT-HAMLIN-HAND-HUGHES-HYDE-JONES- LYMAN-MARSHALL-MCPHERSON-POTTER-ROBERTS-SPINK-STANLEY-SULLY- WALWORTH. MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BIG STONE-TRAVERSE. && $$ UPDATE...CONNELLY SHORT TERM...KEEFE LONG TERM...TMT AVIATION...TMT WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 342 PM CST TUE FEB 12 2008 .DISCUSSION... FRONTAL BOUNDARY JUST NOW MAKING ITS WAY EAST OF THE MS RIVER. THE BULK OF THE SHOWER ACTIVITY IS OVER THE WESTERN THIRD OF THE MID STATE AND EXTENDS WESTWARD ACROSS EASTERN AR AND MUCH OF MO. SCT LIGHT SNOW SHOWERS ARE FALLING ACROSS A GOOD PORTION OF THE NW TWO THIRDS OF MO. 12Z MODEL DATA NOT MUCH HELP WITH THE FCST OVERNIGHT. HOWEVER...RUC AND NAM 18Z SOLUTIONS SHOWING THAT THE PRECIP OVER WESTERN KY AND POINTS WEST SHOULD MOVE ACROSS MIDDLE TN OVERNIGHT. MEANWHILE...COLDER AIR IS BEGINNING TO SPILL INTO NW SECTIONS OF THE MID STATE. CKV SAW A 15 DEGREE DROP AS THE FRONT PUSHED THOUGH AROUND 2 PM. THEY ARE CURRENTLY AT 34 DEGREES. SHOULD SEE THE FREEZING LINE SLOWLY MOVE SOUTHEAST TONIGHT. THIS WILL CREATE A MIXTURE OF RAIN...SLEET AND FREEZING RAIN. ADDITIONALLY...AS THE DEEPER COLDER AIR MOVES IN SOME LIGHT SNOW WILL BE POSSIBLE LATE TONIGHT. WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR ROUGHLY THE NORTHERN TWO THIRDS OF THE MID STATE. ICE AND SLEET ACCUMULATIONS WILL AVERAGE AROUND ONE TENTH OF AN INCH. TRAVEL PROBLEMS WILL LIKELY DEVELOP AS OVERNIGHT LOWS WILL DROP DOWN INTO THE MID 20S FOR MANY AREAS. AREAS ALONG THE PLATEAU WILL SEE THE FREEZING PRECIP HOLD OFF UNTIL AFTER MIDNIGHT. PRECIP SHOULD END OVER THE PLATEAU BY SUNRISE. LOW LEVEL CLOUDINESS WILL REMAIN THROUGH THE MORNING HOURS ON WEDNESDAY. THEN IT LOOKS AS THOUGH PARTIAL CLEARING WILL OCCUR IN THE AFTERNOON. IT WILL BE RATHER COLD AS THE MERCURY STRUGGLE TO REACH THE MID 30S. SFC HIGH BUILDS IN WED NT BUT DEW POINTS WILL NOT BE TOO TERRIBLY LOW. HENCE...LOW TEMPS SHOULD BE IN THE 20-25 DEGREE RANGE. FOR NEAR TERM TEMPS...CLOUDS MAY HANG ON OVER THE PLATEAU ON WED SO I WILL UNDERCUT THE 34 FOR CSV. WED NT...SFC HIGH IS VERY CLOSE TO THE MID STATE ON 12Z THU. THUS...I WILL UNDERCUT THE 26 LOW AT BNA. IN THE EXT FCST...NEXT STORM SYSTEM COMES BACK AT US ON FRIDAY IN THE FORM OF A SFC LOW WHICH WILL TRACK ACROSS THE NORTHERN GULF. PRECIP LOOKS GENERALLY LIGHT ACROSS TN BUT TEMPS MAY SUPPORT RAIN OR SNOW FOR FRI NT. THEN ANOTHER...AND POTENTIALLY MORE POTENT WINTER WEATHER SYSTEM ATTEMPTS TO REAR ITS HEAD ON SUNDAY. ITS STILL A GOOD 5 DAYS OFF BUT BEARS WATCHING AS THIS SYSTEM MAY CARRY A CLOSED UPPER LOW WITH FAVORABLE CYCLOGENESIS ON ITS EASTERN OR SOUTHEASTERN PERIPHERY. FOR NOW...WILL INCLUDE A CHANCE OF RAIN OR SNOW FOR SUNDAY...AND THEN A CHANCE OF SNOW SHOWERS FOR SUN NT INTO EARLY MONDAY AS 850 MB TEMPS DROP WELL BELOW 0C. FOR EXT TEMPS...WILL UNDERCUT HIGHS FOR SUN THROUGH TUES. .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 25 34 23 52 / 60 10 0 0 CLARKSVILLE 22 34 23 52 / 60 10 0 0 CROSSVILLE 27 31 22 49 / 70 10 0 0 COLUMBIA 27 36 23 54 / 60 10 0 0 LAWRENCEBURG 28 37 23 54 / 50 10 0 0 WAVERLY 24 36 24 53 / 60 10 0 0 && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM CST WEDNESDAY FOR TNZ005>011- 022>034-056>060-062>066. && $$ 21 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 900 PM EST MON FEB 11 2008 .DISCUSSION...NO CHANGES. LATEST RUC MODEL KEEPS BAND OF PRECIP WELL TO OUR NORTH THROUGH THE FIRST PERIOD. HOWEVER...RADAR MOSAIC SHOWS LIGHT RETURNS UNCOMFORTABLY CLOSE TO THE TN/KY BORDER. AS SUCH AM RELUCTANT TO REMOVE SLIGHT CHANCE POPS IN OUR NORTHERN TIER ZONES. REMAINDER OF FORECAST APPEARS ON TRACK AND NO CHANGES WARRANTED AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 37 62 36 42 26 / 10 50 90 10 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 34 59 35 39 22 / 10 50 100 30 10 OAK RIDGE, TN 34 57 34 39 22 / 10 50 90 30 10 TRI CITIES AIRPORT, TN 29 57 36 37 22 / 10 50 100 40 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ LCM tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 120 PM CST TUE FEB 12 2008 .UPDATE... SENDING OUT AN UPDATE TO DROP MOST OF THE POPS FOR THIS AFTERNOON. THE EXCEPTION WILL BE ALONG THE IMMEDIATE COAST...BAYS...AND GULF WATERS. 40 && .PREV DISCUSSION... /ISSUED 1006 AM CST TUE FEB 12 2008/ UPDATE... AT 15Z THE BEST DYNAMICS WERE TO THE NORTHEAST OF THE FORECAST AREA. A 12Z UPPER AIR ANALYSIS AND THE 12Z NAM AND RUC MODELS INDICATE STILL A SLIGHT RISK FOR SEVERE WEATHER AS THE LINE OF STORMS PUSHES THROUGH LATER THIS MORNING AND EARLY THIS AFTERNOON. ONE FAVORABLE FACTOR IS THE TEMPERATURES NEAR 70 AND DEWPOINTS IN THE UPPER 60S NUDGING NORTHWARD FROM THE MATAGORDA BAY AREA. THE UPPER JET STRUCTURE FAVORS THE BEST AREA FOR ISOLATED SEVERE STORMS TO BE MORE OVER THE FAR EASTERN SET OF COUNTIES...MAINLY EAST OF THE HIGHWAY 59 CORRIDOR AND NORTH OF THE I-10 CORRIDOR. CURRENTLY THE RADAR INDICATES A SLIGHT BOWING OF THE LINE OF STORMS PUSHING ACROSS WALLER...MONTGOMERY...AND FAR NORTHWESTERN HARRIS COUNTIES. HOWEVER...MOST AREAS WILL SEE MAINLY SHOWERS AND THUNDERSTORMS. FOR NOW WILL ISSUE AN UPDATE FOR TEMPERATURE AND MOISTURE PARAMETERS. OTHERWISE...THE CURRENT FORECAST LOOKS GOOD FOR THE WEATHER AND POP GRIDS. 40 PREV DISCUSSION... /ISSUED 353 AM CST TUE FEB 12 2008/ DISCUSSION... THE SHORTWAVE TROUGH THAT BROUGHT THE BOW ECHO ACROSS THE COASTAL PLAIN OF THE UPPER TX COAST HAS PUSHED INTO THE NORTHERN GULF. ANOTHER SHORTWAVE IN THE CENTRAL PLAINS WILL CONTINUE TO PUSH EAST WITH A STRONG 120KT 300MB JET DIVING INTO IT OVER THE NORTHERN ROCKIES. THE SHORTWAVE MAY DIG A BIT BUT THE JET WILL SERVE TO HELP PUSH THE COLD FRONT THROUGH THE AREA TODAY. SFC OBS AND REGIONAL RADAR IMAGERY SHOW THE FRONT MAINLY FROM A KBWD TO KOSA LINE. CONVECTION IS FILLING IN NICELY ALL ALONG IT. A FEW CELLS MAY BECOME SEVERE LATER THIS MORNING. THE MAIN SEVERE THUNDERSTORM THREAT APPEARS TO BE DURING THE LATE MORNING HOURS WHERE THERE HAS BEEN SOME HEATING AHEAD OF THE FRONT. THIS MAY ALLOW FOR MODERATE CAPE OF 1000-2000 J/KG TO DEVELOP BY 15Z THIS MORNING. THERE SHOULD BE ENOUGH DEEP LAYER SHEAR ON THE ORDER OF 40KTS OR SO FOR STORMS TO ORGANIZE ALONG THE FRONT...POSSIBLY A FEW BOWS WHICH WILL HEIGHTEN THE DAMAGING WIND THREAT. A FEW STORMS MAY ROTATE IF SFC FLOW STAYS BACKED ENOUGH BUT STILL THINK GIVEN THE LINEAR FORCING OF THE FRONT THAT AN ORGANIZED SQUALL LINE WILL BE LIKELY CONVECTIVE MODE. FRONT SHOULD REACH THE COAST BETWEEN 18Z AND 21Z AND OUT OF THE COASTAL WATERS BY 00Z. THE MIDDLE OF THE WEEK SHOULD DRY OUT WITH HIGH PRESSURE BUILDING OVER THE AREA WED AND SHIFTING EAST. RETURN FLOW SHOULD SET UP ON THURSDAY INTO FRIDAY. THIS IS WHERE THE CHALLENGING PART OF THE FORECAST BEGINS. THE 06Z NAM AND 00Z GFS/ECMWF BRING A COLD FRONT INTO THE AREA FRIDAY. A STRONG UPPER LEVEL TROUGH DIGS OVER THE GREAT BASIN AND 4 CORNERS REGION ON THURSDAY SETTING UP STRONG WSW FLOW ALOFT. THIS UPPER TROUGH BECOMES CLOSED OFF FROM THE FLOW AND SLOWLY EDGES EAST OVER THE SOUTHERN ROCKIES. STRONG DIFFLUENCE ALOFT DEVELOPS OVER MUCH OF TX WITH ISENTROPIC LIFT OVER THE FRONTAL BOUNDARY ON FRIDAY INTO SATURDAY. DECIDED THAT A FEW THUNDERSTORMS WILL BE POSSIBLE SHOULD THE FRONTAL BOUNDARY EDGE NORTH A LITTLE BIT AND OPEN THE WARM SECTOR UP OVER SE TX. ELEVATED CONVECTION WILL ALSO BE POSSIBLE GIVEN A SHALLOW COLD AIRMASS. THE 00Z ECMWF SUGGESTS THIS POSSIBILITY. THE 00Z GFS IS A LITTLE MORE PROGRESSIVE WITH THE TROUGH THAN THE ECMWF. IT BRINGS THE TROUGH THROUGH THE AREA LATE SAT INTO SUN WITH HEAVY RAIN. CONDITIONS CLEAR OUT SUN AFTERNOON. THE 00Z ECMWF IS SLOWER WITH IT CLEARING OUT SUN NIGHT INTO MON. LOOKING AT THE 00Z GFS ENSEMBLE MEAN AND ITS MEMBERS...WILL STICK MORE TO THE POSSIBILITY OF A SLOWER PROGRESSION OF THE TROUGH. AGREE THAT BULK OF THE RAIN WILL OCCUR FRI/SAT AND WILL BUMP POPS UP TO 60 PERCENT DURING THIS TIME. FOR NOW WITH THE EVENT STILL SEVERAL DAYS AHEAD...30 POPS FOR SUN LOOK REASONABLE BEFORE CLEARING POPS ON MON. IT IS A BIT DIFFICULT TO NAIL DOWN THE DETAILS OF THE EVENT BUT THERE MAY BE A SLIGHT SEVERE THUNDERSTORM RISK AHEAD OF THE FRONT. OTHERWISE...THIS SCENARIO LOOKS LIKE A GOOD HEAVY RAINFALL EVENT AND BEARS WATCHING. BOTH THE NAM AND GFS BRING ABOUT 1.5 INCHES OF PWAT INTO THE UPPER TX COAST AND GALVESTON BAY. WITH ALL THE STRONG LIFT ASSOCIATED WITH THE FRONT...UPPER LEVEL DYNAMICS AND MOISTURE...POSSIBLE FOR SOME AREAS TO SEE QUITE A BIT OF RAINFALL. OVERPECK/39 AVIATION... STILL EXPECTING A LOW DECK TO FORM BY SUNRISE AS MOISTURE CONTINUES TO STREAM INTO THE AREA. THINGS SHOULD MIX OUT BY MID-MORNING AHEAD OF A COLD FRONT. THE FRONT SHOULD CLL BETWEEN 15-16Z...IAH AROUND 18Z AND GLS AROUND 20Z. WILL CARRY PREVAILING TSRA WITH THE FROPA AND ADD WIND GUSTS. NW WINDS WILL INCREASE BEHIND THE FRONT. WILL LEAN TOWARD THE SLOWER CLEARING AS OFFERED BY THE NAM. MAINLY VFR OVERNIGHT. 43 MARINE... EXPECT THE NEXT FRONT AND ASSOCIATED LINE OF SHOWERS AND THUNDERSTORMS TO PUSH OFF THE COAST BETWEEN 1 PM AND 3 PM. WILL MENTION SEVERE IN THE MARINE TEXT. MODERATE TO STRONG OFFSHORE FLOW WILL DEVELOP IN THE WAKE OF THE FRONT. WINDS/SEAS GRADUALLY DIMINISH WED AS HIGH PRES BUILDS INTO THE AREA. ONSHORE FLOW RESUMES WED NIGHT...INCREASES THURS...THEN ANOTHER FRONT AND ASSOCIATED STORMS FRI AFTN OR EVNG. PREFER THE SLOWER ECMWF OVER THE WEEKEND WHICH HOLDS THE WIND SHIFT BACK UNTIL SUNDAY NIGHT. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 67 36 65 48 71 / 80 10 0 10 10 HOUSTON (IAH) 69 39 64 46 71 / 80 10 0 10 10 GALVESTON (GLS) 68 45 60 53 68 / 70 10 0 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 AM CST WEDNESDAY FOR THE FOLLOWING ZONES: GALVESTON BAY... MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...40 AVIATION/MARINE...47 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 1006 AM CST TUE FEB 12 2008 .UPDATE... AT 15Z THE BEST DYNAMICS WERE TO THE NORTHEAST OF THE FORECAST AREA. A 12Z UPPER AIR ANALYSIS AND THE 12Z NAM AND RUC MODELS INDICATE STILL A SLIGHT RISK FOR SEVERE WEATHER AS THE LINE OF STORMS PUSHES THROUGH LATER THIS MORNING AND EARLY THIS AFTERNOON. ONE FAVORABLE FACTOR IS THE TEMPERATURES NEAR 70 AND DEWPOINTS IN THE UPPER 60S NUDGING NORTHWARD FROM THE MATAGORDA BAY AREA. THE UPPER JET STRUCTURE FAVORS THE BEST AREA FOR ISOLATED SEVERE STORMS TO BE MORE OVER THE FAR EASTERN SET OF COUNTIES...MAINLY EAST OF THE HIGHWAY 59 CORRIDOR AND NORTH OF THE I-10 CORRIDOR. CURRENTLY THE RADAR INDICATES A SLIGHT BOWING OF THE LINE OF STORMS PUSHING ACROSS WALLER...MONTGOMERY...AND FAR NORTHWESTERN HARRIS COUNTIES. HOWEVER...MOST AREAS WILL SEE MAINLY SHOWERS AND THUNDERSTORMS. FOR NOW WILL ISSUE AN UPDATE FOR TEMPERATURE AND MOISTURE PARAMETERS. OTHERWISE...THE CURRENT FORECAST LOOKS GOOD FOR THE WEATHER AND POP GRIDS. 40 && .PREV DISCUSSION... /ISSUED 353 AM CST TUE FEB 12 2008/ DISCUSSION... THE SHORTWAVE TROUGH THAT BROUGHT THE BOW ECHO ACROSS THE COASTAL PLAIN OF THE UPPER TX COAST HAS PUSHED INTO THE NORTHERN GULF. ANOTHER SHORTWAVE IN THE CENTRAL PLAINS WILL CONTINUE TO PUSH EAST WITH A STRONG 120KT 300MB JET DIVING INTO IT OVER THE NORTHERN ROCKIES. THE SHORTWAVE MAY DIG A BIT BUT THE JET WILL SERVE TO HELP PUSH THE COLD FRONT THROUGH THE AREA TODAY. SFC OBS AND REGIONAL RADAR IMAGERY SHOW THE FRONT MAINLY FROM A KBWD TO KOSA LINE. CONVECTION IS FILLING IN NICELY ALL ALONG IT. A FEW CELLS MAY BECOME SEVERE LATER THIS MORNING. THE MAIN SEVERE THUNDERSTORM THREAT APPEARS TO BE DURING THE LATE MORNING HOURS WHERE THERE HAS BEEN SOME HEATING AHEAD OF THE FRONT. THIS MAY ALLOW FOR MODERATE CAPE OF 1000-2000 J/KG TO DEVELOP BY 15Z THIS MORNING. THERE SHOULD BE ENOUGH DEEP LAYER SHEAR ON THE ORDER OF 40KTS OR SO FOR STORMS TO ORGANIZE ALONG THE FRONT...POSSIBLY A FEW BOWS WHICH WILL HEIGHTEN THE DAMAGING WIND THREAT. A FEW STORMS MAY ROTATE IF SFC FLOW STAYS BACKED ENOUGH BUT STILL THINK GIVEN THE LINEAR FORCING OF THE FRONT THAT AN ORGANIZED SQUALL LINE WILL BE LIKELY CONVECTIVE MODE. FRONT SHOULD REACH THE COAST BETWEEN 18Z AND 21Z AND OUT OF THE COASTAL WATERS BY 00Z. THE MIDDLE OF THE WEEK SHOULD DRY OUT WITH HIGH PRESSURE BUILDING OVER THE AREA WED AND SHIFTING EAST. RETURN FLOW SHOULD SET UP ON THURSDAY INTO FRIDAY. THIS IS WHERE THE CHALLENGING PART OF THE FORECAST BEGINS. THE 06Z NAM AND 00Z GFS/ECMWF BRING A COLD FRONT INTO THE AREA FRIDAY. A STRONG UPPER LEVEL TROUGH DIGS OVER THE GREAT BASIN AND 4 CORNERS REGION ON THURSDAY SETTING UP STRONG WSW FLOW ALOFT. THIS UPPER TROUGH BECOMES CLOSED OFF FROM THE FLOW AND SLOWLY EDGES EAST OVER THE SOUTHERN ROCKIES. STRONG DIFFLUENCE ALOFT DEVELOPS OVER MUCH OF TX WITH ISENTROPIC LIFT OVER THE FRONTAL BOUNDARY ON FRIDAY INTO SATURDAY. DECIDED THAT A FEW THUNDERSTORMS WILL BE POSSIBLE SHOULD THE FRONTAL BOUNDARY EDGE NORTH A LITTLE BIT AND OPEN THE WARM SECTOR UP OVER SE TX. ELEVATED CONVECTION WILL ALSO BE POSSIBLE GIVEN A SHALLOW COLD AIRMASS. THE 00Z ECMWF SUGGESTS THIS POSSIBILITY. THE 00Z GFS IS A LITTLE MORE PROGRESSIVE WITH THE TROUGH THAN THE ECMWF. IT BRINGS THE TROUGH THROUGH THE AREA LATE SAT INTO SUN WITH HEAVY RAIN. CONDITIONS CLEAR OUT SUN AFTERNOON. THE 00Z ECMWF IS SLOWER WITH IT CLEARING OUT SUN NIGHT INTO MON. LOOKING AT THE 00Z GFS ENSEMBLE MEAN AND ITS MEMBERS...WILL STICK MORE TO THE POSSIBILITY OF A SLOWER PROGRESSION OF THE TROUGH. AGREE THAT BULK OF THE RAIN WILL OCCUR FRI/SAT AND WILL BUMP POPS UP TO 60 PERCENT DURING THIS TIME. FOR NOW WITH THE EVENT STILL SEVERAL DAYS AHEAD...30 POPS FOR SUN LOOK REASONABLE BEFORE CLEARING POPS ON MON. IT IS A BIT DIFFICULT TO NAIL DOWN THE DETAILS OF THE EVENT BUT THERE MAY BE A SLIGHT SEVERE THUNDERSTORM RISK AHEAD OF THE FRONT. OTHERWISE...THIS SCENARIO LOOKS LIKE A GOOD HEAVY RAINFALL EVENT AND BEARS WATCHING. BOTH THE NAM AND GFS BRING ABOUT 1.5 INCHES OF PWAT INTO THE UPPER TX COAST AND GALVESTON BAY. WITH ALL THE STRONG LIFT ASSOCIATED WITH THE FRONT...UPPER LEVEL DYNAMICS AND MOISTURE...POSSIBLE FOR SOME AREAS TO SEE QUITE A BIT OF RAINFALL. OVERPECK/39 AVIATION... STILL EXPECTING A LOW DECK TO FORM BY SUNRISE AS MOISTURE CONTINUES TO STREAM INTO THE AREA. THINGS SHOULD MIX OUT BY MID-MORNING AHEAD OF A COLD FRONT. THE FRONT SHOULD CLL BETWEEN 15-16Z...IAH AROUND 18Z AND GLS AROUND 20Z. WILL CARRY PREVAILING TSRA WITH THE FROPA AND ADD WIND GUSTS. NW WINDS WILL INCREASE BEHIND THE FRONT. WILL LEAN TOWARD THE SLOWER CLEARING AS OFFERED BY THE NAM. MAINLY VFR OVERNIGHT. 43 MARINE... EXPECT THE NEXT FRONT AND ASSOCIATED LINE OF SHOWERS AND THUNDERSTORMS TO PUSH OFF THE COAST BETWEEN 1 PM AND 3 PM. WILL MENTION SEVERE IN THE MARINE TEXT. MODERATE TO STRONG OFFSHORE FLOW WILL DEVELOP IN THE WAKE OF THE FRONT. WINDS/SEAS GRADUALLY DIMINISH WED AS HIGH PRES BUILDS INTO THE AREA. ONSHORE FLOW RESUMES WED NIGHT...INCREASES THURS...THEN ANOTHER FRONT AND ASSOCIATED STORMS FRI AFTN OR EVNG. PREFER THE SLOWER ECMWF OVER THE WEEKEND WHICH HOLDS THE WIND SHIFT BACK UNTIL SUNDAY NIGHT. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 65 36 65 48 71 / 80 10 0 10 10 HOUSTON (IAH) 69 39 64 46 71 / 80 10 0 10 10 GALVESTON (GLS) 68 45 60 53 68 / 80 10 0 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 4 AM CST WEDNESDAY FOR THE FOLLOWING ZONES: GALVESTON BAY... MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...40 AVIATION/MARINE...47 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 906 AM CST TUE FEB 12 2008 .DISCUSSION...SATELLITE AND RADAR IMAGES INDICATE SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE TO DEVELOP OVER PORTIONS OF DEEP SOUTH TEXAS AND NORTHEAST MEXICO THIS MORNING. RUC80 200MB WIND SPEED ANALYSIS INDICATED RIGHT FRONT QUADRANT OF A STRONG JET MOVING EASTWARD ACROSS SOUTH TX AND THIS IS PROVIDING Q-VECTOR CONVERGENCE NOT ONLY FOR THE CONVECTION ACROSS THE LOWER RIO GRANDE VALLEY BUT THE STRONGER LINE OF CONVECTION MOVING THROUGH EAST TX AHEAD OF THE COLD FRONT. MAIN QUESTION TODAY IS THE EXTENT OF THE LINE OF SHOWERS AND THUNDERSTORMS ACROSS EAST TEXAS WILL MOVE ACROSS THE COASTAL BEND INTO THE CWA THIS AFTERNOON AND POTENTIAL FOR SEVERE WEATHER. IT APPEARS THE LOW LEVEL JET PROGGED BY THE NAM80 ACROSS THE LOWER TX COAST IS BEING INHIBITED BY THE CONVECTION ACROSS NORTHEAST MEXICO. LAPS SURFACE ANALYSIS INDICATED LIFTING INDICES OF -4 TO -5 ACROSS DEEP SOUTH TX. WARMER 850MB TEMPERATURES ACROSS THE RIO GRANDE PLAINS MAY PROVIDE A WEAK CAP TODAY. BELIEVE AS THE FRONT MOVES FURTHER SOUTH...THE CAP SHOULD ERODE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP. WITH TEMPERATURES REACHING THE LOWER 80S THIS AFTERNOON...BELIEVE ENOUGH INSTABILITY FOR SOME ISOLATED STRONG THUNDERSTORMS TO DEVELOP SO WILL MENTION GUSTY WINDS WITH SOME STORMS MAINLY IN THE AFTERNOON. HAVE ALREADY UPDATED GRIDS/ZONES TO INCREASE POPS MAINLY FOR THIS AFTERNOON. WILL HAVE TO CONTINUE TO MONITOR THE DEVELOPMENT OF THE LINE OF SHOWERS AND THUNDERSTORMS ACROSS EAST TX MOVING SOUTHWARD AND IF ADDITIONAL SHOWERS AND THUNDERSTORMS DEVELOP AHEAD OF THIS BOUNDARY. && .AVIATION...PREVAIL VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS WITH TEMPO MVFR CONDITIONS IN CIGS/VSBYS IN ANY SHOWERS OR THUNDERSTORMS. WINDS WILL BE MODERATE FROM THE SOUTHEAST TODAY AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA TONIGHT. MODERATE NORTH WINDS WILL PREVAIL TONIGHT IN THE WAKE OF THE COLD FRONT. && .MARINE...AT 8AM BUOY020 REPORTED SOUTH TO SOUTHEAST WINDS AT 12 TO 14 KNOTS AND SEAS 4.6 FEET WITH AN 8 SECOND PERIOD. WINDS AND SEAS ARE STILL BELOW SMALL CRAFT ADVISORY CRITERIA. THE COLD FRONT IS PRESENTLY OVER CENTRAL TEXAS AND WILL NOT MOVE THROUGH THE COASTAL WATERS OF DEEP SOUTH TEXAS UNTIL AT LEAST 6 PM TONIGHT. THEREFORE WILL NOT BEGIN THE SMALL CRAFT ADVISORY UNTIL 6 PM TONIGHT. WINDS WILL NOT QUITE REACH SMALL CRAFT ADVISORY CRITERIA OVER THE LAGUNA SO WILL DROP THE SMALL CRAFT ADVISORY FOR THAT AREA AT THIS TIME. WINDS SHIFT BACK TO THE SOUTHEAST BY MIDNIGHT THURSDAY AS HIGH PRESSURE MOVES TO THE EAST. WINDS LATER IN THE WEEK WILL BE GUSTY IN RESPONSE TO A SECOND APPROACHING COLD FRONT. && .PREV DISCUSSION... /ISSUED 316 AM CST TUE FEB 12 2008/ THE VALLEY CAN EXPECT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS TODAY WITH A BETTER CHANCE OF RAIN SATURDAY. THE COMBINATION OF WEAK DISTURBANCES MOVING WEST TO EAST ACROSS NORTHERN MEXICO AND A COLD FRONT HEADING SOUTH SHOULD PROVIDE A SLIGHT CHANCE OF CONVECTION TODAY. ALTHOUGH 00Z MODEL GUIDANCE WAS BEARISH IN THE POSSIBILITIES WENT SLIGHT HIGHER. POINT OF INTEREST IN THE GUIDANCE IS THAT ALTHOUGH POPS ARE LOW THE CONDITIONAL PROBABILITY OF A SEVERE THUNDERSTORM IS 40 TO 60 PERCENT. WONT MENTION SEVERE IN THE ZFP BUT WILL PLAY IT UP IN THE HWO. THE COLD FRONT IS CURRENTLY JUST WEST OF THE HILL COUNTRY AND IS ON TRACK TO PUSH OFF SHORE BY SUNSET THIS EVENING. RAIN CHANCES ENDING WEST TO EAST WITH DRIER AND COOLER WEATHER TO FOLLOW THE FRONTAL PASSAGE. HIGH PRESSURE BUILDS OVER THE CWA ON WEDNESDAY WITH A PLEASANT DAY IN STORE. RETURN FLOW STARTS UP WEDNESDAY NIGHT AND PICKS UP THURSDAY AS THE NEXT UPSTREAM TROUGH DIGS INTO THE FOUR CORNERS REGION. HERE IS WHEN IT GETS INTERESTING. UPPER LOW TO SETTLE OVER THE DESERT SW AND WEST TEXAS FRIDAY INTO SATURDAY. DIFFERENCE ON TIMING CONTINUES WITH THE MEDIUM RANGE MODELS BUT ALL OF THEM CONTINUE TO SHOW A SLOWER EASTWARD PROGRESSION WITH THE UPPER LOW AND TROUGH AS WELL AS THE ASSOCIATED COLD FRONT. UPDATED FORECAST INDICATES THE FRONT TO MOVE OFFSHORE LATE FRIDAY NIGHT WITH RAIN AND DRIZZLE TO INCREASE BY SATURDAY MORNING. AN ALL DAY RAIN DRIZZLE EVENT IS POSSIBLE SATURDAY WITH THE UPPER LOW SITTING OVER WEST TEXAS AND A COASTAL TROUGH DEVELOPING. TEMPERATURES SHOULD BE COOL AND POSSIBLY COOLER THEN THE UPPER 50S TO MID 60S WHICH IS CURRENTLY FORECAST FOR SATURDAY. AT THIS TIME HAVE THE SYSTEM EJECTING NE SUNDAY AM WITH POPS ENDING AND TEMPS RECOVERING. IF HOWEVER...THE SYSTEM TRENDS EVEN SLOWER THE RAIN...DRIZZLE AND COOL TEMPS COULD LINGER INTO SUNDAY. AVIATION...AREA WINDS REMAIN AROUND 10KTS THIS MORNING...WITH CLOUD COVER LIMITED TO MIDLEVEL CIRRUS. WINDS JUST OFF THE SFC ARE RUNNING 35 TO 40KTS FROM 1-3KFT. WILL UPDATE TAFS FOR SHEAR. FOG STARTING TO FORM HBV/BKS/EBG AND OTHER OUTLYING AREAS...AND SHOULD SLOWLY MOVE INTO OTHER AIRPORTS BEFORE DAWN. FOG WILL BURN OFF QUICKLY AFTER SUNRISE. VFR CONDITIONS WILL START THE DAY...BUT SOME LOWER CIGS ARE EXPECTED IN THE AFTERNOON AS THE FRONT ARRIVES AFTER 3PM. WINDS WILL QUICKLY SWITCH TO THE NORTH BEHIND THE FRONT. SKIES REMAIN MOSTLY CLEAR OVERNIGHT. MARINE...AT 2AM BUOY020 REPORTED SOUTHEAST WINDS AT 14KTS AND SEAS 5.5 FEET WITH AN 8 SECOND PERIOD. SEAS AREA ALREADY HIGHER AS MODERATE AND LONGER FETCH SOUTHEAST WINDS PUSH HIGHER WAVES INTO THE NORTHWEST GULF. A COLD FRONT WILL SWEEP THROUGH THE COASTAL WATERS BETWEEN NOON AND 6PM TODAY...SWITCHING WINDS TO THE NORTH AND REACHING 25 KNOTS SUSTAINED. SMALL CRAFT SHOULD EXERCISE CAUTION ON THE GULF AND LAGUNA THIS MORNING...WITH ADVISORIES ALREADY POSTED BEGINNING LATER THIS AFTERNOON. WINDS SHIFT BACK TO THE SOUTHEAST BY MIDNIGHT THURSDAY AS HIGH PRESSURE MOVES TO THE EAST. WINDS LATER IN THE WEEK WILL BE GUSTY IN RESPONSE TO A SECOND APPROACHING COLD FRONT. LONGER RANGE MODELS ARE STILL DIFFERING ON TIMING. HAVE GONE WITH A SLIGHTLY SLOWER SOLUTION...WITH THE FRONT REACHING LATE FRIDAY. ADVISORIES WILL AGAIN BE NEEDED. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 80 53 71 57 / 40 20 0 0 BROWNSVILLE 82 54 75 57 / 40 20 0 0 HARLINGEN 83 52 76 54 / 40 20 0 0 MCALLEN 85 52 76 54 / 40 10 0 0 RIO GRANDE CITY 84 48 75 53 / 30 10 0 0 SOUTH PADRE ISLAND 77 55 69 59 / 40 30 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 12 PM CST WEDNESDAY FOR GMZ130-132-135-150-155-170-175. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WWW.WEATHER.GOV/BROWNSVILLE PUBLIC/GRIDS...61 MARINE/AVIATION...65 MESO...CAMPBELL tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 808 PM CST MON FEB 11 2008 .UPDATE...MADE SOME COSMETIC CHANGES TO THE VARIOUS GRIDDED PARAMETERS TONIGHT. MINOR ADJUSTMENTS HAVE BEEN MADE TO THE NEAR- TERM TEMPERATURES AND SKY GRIDS TO BETTER REFLECT CURRENT TRENDS. MADE SOME CHANGES TO THE NOCTURNAL POPS TO REFLECT NIL TO CLOSE TO NIL CHANCES OF PRECIPITATION. OTHERWISE...PREVIOUS FORECAST TRENDS ON TRACK AND NO OTHER CHANGES ARE ANTICIPATED. && .PREV DISCUSSION... /ISSUED 541 PM CST MON FEB 11 2008/ AVIATION...VFR CONDITIONS ACROSS SOUTH TEXAS THIS EVENING WILL DETERIORATE TO LIFR/VLIFR VSBYS AFTER MIDNIGHT ACROSS THE INLAND SECTIONS OF THE COASTAL BEND. ONLY MVFR CIGS ARE EXPECTED OVER KLRD AND IFR CONDITIONS EXPECTED OVER KCRP AROUND SUNRISE. A COLD FRONT WILL PUSH THROUGH SOUTH TEXAS DURING THE MID TO LATE MORNING HOURS AND SCOUR OUT THE LOW LEVEL MOISTURE. THERE COULD BE CONVECTIVE DEVELOPMENT ALONG THE FRONT...MAINLY EAST OF HIGHWAY 16. VFR CONDITIONS AND GUSTY NORTHERLY WINDS WILL DEVELOP BEHIND THE FRONT TUESDAY AFTERNOON AND CONTINUE THROUGH THE EVENING. PREV DISCUSSION... /ISSUED 229 PM CST MON FEB 11 2008/ SHORT TERM...TWO MAIN FEATURES OF INTEREST OVER THE SHORT TERM. THE FIRST IS AN UPPER LOW CURRENTLY IN PROGRESS ACROSS SOUTH TEXAS. FAVORABLE LAPSE RATES ALOFT HAVE ALLOWED CONVECTION TO TRIGGER...MAINLY IN A RELATIVELY COOL POOL ALOFT AS PER HOURLY RUC GRAPHICS. SOME CONVECTION HAS RECENTLY INITIATED FURTHER SOUTHWEST...ALONG AN APPARENT BACK EDGE TO USABLE LIFT AS PER 88D AND SATELLITE IMAGERY. EXPECT SOME CLEARING THIS EVENING IN THE WAKE OF THE UPPER LOW...AND WITH CONTINUING HIGH BLYR MOISTURE FOG FORMATION IS AGAIN FAVORED TONIGHT. A MUCH STRONGER BOUNDARY WORKS THROUGH THE REGION ON TUESDAY. DECENT DYNAMICS AND RELATIVELY HIGH PWATS SHOULD TRIGGER HIGH COVERAGE SHOWERS AND A FEW THUNDERSTORMS ESPECIALLY OVER THE NORTHEAST WHERE CONDITIONS ARE MOST FAVORABLE. NORTHERLY SURFACE WINDS AND MUCH DRIER AIR FILTER IN BEHIND THE FRONT. INITIAL CAA BEHIND THE FRONT SHOULD INHIBIT AFTERNOON HIGH TEMPERATURES...WITH MANY LOCATIONS REACHING HIGHS FAIRLY EARLY...THEN HOLDING STEADY OR PERHAPS FALLING A COUPLE OF DEGREES IN THE AFTERNOON. AVIATION...GENERALLY VFR CONDITIONS THIS AFTERNOON WITH SCATTERED CONVECTION. IFR VSBYS AND CIGS DEVELOP AGAIN OVERNIGHT...NOT COMPLETELY DEPARTING UNTIL FROPA LATE TUESDAY MORNING. FROPA WILL SWING WINDS NW THEN N AND SCOUR OUT LOW CIGS AS DRIER AIR MOVES IN. MARINE...LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE OVERNIGHT WITH SEA FOG DEVELOPING. FLOW WILL RAPIDLY TURN OFFSHORE AND INCREASE...ESPECIALLY IN THE IMMEDIATE WAKE OF THE FRONTAL PASSAGE. FLOW SHOULD REMAIN ABOVE SCA CRITERIA THROUGH TUESDAY NIGHT. LONG TERM (WEDNESDAY THROUGH MONDAY)...ONSHORE FLOW WILL STRENGTHEN WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT AS A SURFACE CYCLONE DEEPENS OVER WEST TEXAS. BREEZY/WINDY CONDITIONS EXPECTED THURSDAY AFTERNOON/EVENING(POSSIBLY ADVISORY LEVELS) GIVEN SURFACE PRESSURE GRADIENT/ISALLOBARIC PRESSURE FALLS/THERMAL GRADIENT. TEMPERATURES WILL CLIMB TO ABOVE NORMAL LEVELS(ESPECIALLY THE COASTAL/RIO GRANDE PLAINS WHERE CLOUDINESS WILL BE LESS PREVALENT AND DRY TOPSOIL WILL BE MOST INFLUENTIAL). SCEC/SCA CONDITIONS WILL OCCUR MOST OF THE TIME OVER THE WATERS. A STRONG MID-LEVEL SHORTWAVE/CLOSED CYCLONE DIVES INTO TEXAS FRIDAY/SATURDAY. MODEL CONSENSUS/ENSEMBLES SUGGEST THE TROUGH AXIS WILL CLEAR THE REGION BY SATURDAY EVENING. HOWEVER...THE LATITUDINAL POSITION IS MORE UNCERTAIN AND WILL ULTIMATELY DICTATE HOW COLD THE AIRMASS WILL BE WHICH IS ORIGINATING FROM WESTERN CANADA. MODELS HAVE BEEN FLIP-FLOPPING WITH COLD FRONTAL TIMING FOR FRIDAY. PREFER THE FASTER 06Z GFS SOLUTION(CANADIAN/NOGAPS IN AGREEMENT) WHICH SWEEPS IT THROUGH DURING THE MORNING GIVEN DENSITY CONSIDERATIONS. MAINTAINED SLIGHT CHANCE POPS WEST TO MID-GRADE CHANCE POPS EAST AS MOISTURE IS SOMEWHAT LACKING AND CAPPING INVERSION IS PRESENT. RETAINED SLIGHT CHANCE POPS WEST AND LOW-END CHANCE POPS EAST FRIDAY NIGHT/SATURDAY AS SIGNIFICANT DYNAMICS OCCURS IN THE MIDST OF AT LEAST SUFFICIENT MID-LEVEL MOISTURE. POST-FRONTAL WINDY/STRONG SCA CONDITIONS EXPECTED GIVEN STRONG ISALLOBARIC PRESSURE RISES/COLD THERMAL ADVECTION. A WIND ADVISORY WILL PROBABLY BE REQUIRED AND THE OFFSHORE WATERS MAY FLIRT WITH GALE WARNING CRITERIA. A SURFACE ANTICYCLONE BUILDS IN SATURDAY NIGHT THEN QUICKLY RETREATS SUNDAY...FOLLOWED BY A DRY RE-ENFORCING COLD FRONT SUNDAY NIGHT. POST-FRONTAL TEMPERATURES WERE WEIGHTED TOWARD THE RAW GFS NUMBERS. MAINTAINED THE RAPID TEMPERATURE RECOVERY SUNDAY AS SIGNIFICANT WARM THERMAL ADVECTION FLOODS THE AREA WITH THE GROUND STILL RELATIVELY DRY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 63 76 43 68 52 / 10 50 10 0 10 VICTORIA 62 71 41 67 46 / 10 60 10 0 10 LAREDO 65 76 43 77 53 / 10 20 10 0 10 ALICE 62 75 40 72 49 / 10 40 10 0 10 ROCKPORT 65 73 46 66 54 / 10 60 10 0 10 COTULLA 62 71 39 75 47 / 10 20 10 0 10 KINGSVILLE 63 75 41 70 50 / 10 40 10 0 10 NAVY CORPUS 66 74 50 66 54 / 10 50 10 0 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ SC/70...SHORT TERM TM/95...LONG TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 541 PM CST MON FEB 11 2008 .AVIATION...VFR CONDITIONS ACROSS SOUTH TEXAS THIS EVENING WILL DETERIORATE TO LIFR/VLIFR VSBYS AFTER MIDNIGHT ACROSS THE INLAND SECTIONS OF THE COASTAL BEND. ONLY MVFR CIGS ARE EXPECTED OVER KLRD AND IFR CONDITIONS EXPECTED OVER KCRP AROUND SUNRISE. A COLD FRONT WILL PUSH THROUGH SOUTH TEXAS DURING THE MID TO LATE MORNING HOURS AND SCOUR OUT THE LOW LEVEL MOISTURE. THERE COULD BE CONVECTIVE DEVELOPMENT ALONG THE FRONT...MAINLY EAST OF HIGHWAY 16. VFR CONDITIONS AND GUSTY NORTHERLY WINDS WILL DEVELOP BEHIND THE FRONT TUESDAY AFTERNOON AND CONTINUE THROUGH THE EVENING. && .PREV DISCUSSION... /ISSUED 229 PM CST MON FEB 11 2008/ SHORT TERM...TWO MAIN FEATURES OF INTEREST OVER THE SHORT TERM. THE FIRST IS AN UPPER LOW CURRENTLY IN PROGRESS ACROSS SOUTH TEXAS. FAVORABLE LAPSE RATES ALOFT HAVE ALLOWED CONVECTION TO TRIGGER...MAINLY IN A RELATIVELY COOL POOL ALOFT AS PER HOURLY RUC GRAPHICS. SOME CONVECTION HAS RECENTLY INITIATED FURTHER SOUTHWEST...ALONG AN APPARENT BACK EDGE TO USABLE LIFT AS PER 88D AND SATELLITE IMAGERY. EXPECT SOME CLEARING THIS EVENING IN THE WAKE OF THE UPPER LOW...AND WITH CONTINUING HIGH BLYR MOISTURE FOG FORMATION IS AGAIN FAVORED TONIGHT. A MUCH STRONGER BOUNDARY WORKS THROUGH THE REGION ON TUESDAY. DECENT DYNAMICS AND RELATIVELY HIGH PWATS SHOULD TRIGGER HIGH COVERAGE SHOWERS AND A FEW THUNDERSTORMS ESPECIALLY OVER THE NORTHEAST WHERE CONDITIONS ARE MOST FAVORABLE. NORTHERLY SURFACE WINDS AND MUCH DRIER AIR FILTER IN BEHIND THE FRONT. INITIAL CAA BEHIND THE FRONT SHOULD INHIBIT AFTERNOON HIGH TEMPERATURES...WITH MANY LOCATIONS REACHING HIGHS FAIRLY EARLY...THEN HOLDING STEADY OR PERHAPS FALLING A COUPLE OF DEGREES IN THE AFTERNOON. AVIATION...GENERALLY VFR CONDITIONS THIS AFTERNOON WITH SCATTERED CONVECTION. IFR VSBYS AND CIGS DEVELOP AGAIN OVERNIGHT...NOT COMPLETELY DEPARTING UNTIL FROPA LATE TUESDAY MORNING. FROPA WILL SWING WINDS NW THEN N AND SCOUR OUT LOW CIGS AS DRIER AIR MOVES IN. MARINE...LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE OVERNIGHT WITH SEA FOG DEVELOPING. FLOW WILL RAPIDLY TURN OFFSHORE AND INCREASE...ESPECIALLY IN THE IMMEDIATE WAKE OF THE FRONTAL PASSAGE. FLOW SHOULD REMAIN ABOVE SCA CRITERIA THROUGH TUESDAY NIGHT. LONG TERM (WEDNESDAY THROUGH MONDAY)...ONSHORE FLOW WILL STRENGTHEN WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT AS A SURFACE CYCLONE DEEPENS OVER WEST TEXAS. BREEZY/WINDY CONDITIONS EXPECTED THURSDAY AFTERNOON/EVENING(POSSIBLY ADVISORY LEVELS) GIVEN SURFACE PRESSURE GRADIENT/ISALLOBARIC PRESSURE FALLS/THERMAL GRADIENT. TEMPERATURES WILL CLIMB TO ABOVE NORMAL LEVELS(ESPECIALLY THE COASTAL/RIO GRANDE PLAINS WHERE CLOUDINESS WILL BE LESS PREVALENT AND DRY TOPSOIL WILL BE MOST INFLUENTIAL). SCEC/SCA CONDITIONS WILL OCCUR MOST OF THE TIME OVER THE WATERS. A STRONG MID-LEVEL SHORTWAVE/CLOSED CYCLONE DIVES INTO TEXAS FRIDAY/SATURDAY. MODEL CONSENSUS/ENSEMBLES SUGGEST THE TROUGH AXIS WILL CLEAR THE REGION BY SATURDAY EVENING. HOWEVER...THE LATITUDINAL POSITION IS MORE UNCERTAIN AND WILL ULTIMATELY DICTATE HOW COLD THE AIRMASS WILL BE WHICH IS ORIGINATING FROM WESTERN CANADA. MODELS HAVE BEEN FLIP-FLOPPING WITH COLD FRONTAL TIMING FOR FRIDAY. PREFER THE FASTER 06Z GFS SOLUTION(CANADIAN/NOGAPS IN AGREEMENT) WHICH SWEEPS IT THROUGH DURING THE MORNING GIVEN DENSITY CONSIDERATIONS. MAINTAINED SLIGHT CHANCE POPS WEST TO MID-GRADE CHANCE POPS EAST AS MOISTURE IS SOMEWHAT LACKING AND CAPPING INVERSION IS PRESENT. RETAINED SLIGHT CHANCE POPS WEST AND LOW-END CHANCE POPS EAST FRIDAY NIGHT/SATURDAY AS SIGNIFICANT DYNAMICS OCCURS IN THE MIDST OF AT LEAST SUFFICIENT MID-LEVEL MOISTURE. POST-FRONTAL WINDY/STRONG SCA CONDITIONS EXPECTED GIVEN STRONG ISALLOBARIC PRESSURE RISES/COLD THERMAL ADVECTION. A WIND ADVISORY WILL PROBABLY BE REQUIRED AND THE OFFSHORE WATERS MAY FLIRT WITH GALE WARNING CRITERIA. A SURFACE ANTICYCLONE BUILDS IN SATURDAY NIGHT THEN QUICKLY RETREATS SUNDAY...FOLLOWED BY A DRY RE-ENFORCING COLD FRONT SUNDAY NIGHT. POST-FRONTAL TEMPERATURES WERE WEIGHTED TOWARD THE RAW GFS NUMBERS. MAINTAINED THE RAPID TEMPERATURE RECOVERY SUNDAY AS SIGNIFICANT WARM THERMAL ADVECTION FLOODS THE AREA WITH THE GROUND STILL RELATIVELY DRY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 63 76 43 68 52 / 10 50 10 0 10 VICTORIA 62 71 41 67 46 / 20 60 10 0 10 LAREDO 65 76 43 77 53 / 10 20 10 0 10 ALICE 62 75 40 72 49 / 10 40 10 0 10 ROCKPORT 65 73 46 66 54 / 10 60 10 0 10 COTULLA 62 71 39 75 47 / 10 20 10 0 10 KINGSVILLE 63 75 41 70 50 / 10 40 10 0 10 NAVY CORPUS 66 74 50 66 54 / 10 50 10 0 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ TM/95...AVIATION tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 229 PM CST MON FEB 11 2008 .SHORT TERM...TWO MAIN FEATURES OF INTEREST OVER THE SHORT TERM. THE FIRST IS AN UPPER LOW CURRENTLY IN PROGRESS ACROSS SOUTH TEXAS. FAVORABLE LAPSE RATES ALOFT HAVE ALLOWED CONVECTION TO TRIGGER...MAINLY IN A RELATIVELY COOL POOL ALOFT AS PER HOURLY RUC GRAPHICS. SOME CONVECTION HAS RECENTLY INITIATED FURTHER SOUTHWEST...ALONG AN APPARENT BACK EDGE TO USABLE LIFT AS PER 88D AND SATELLITE IMAGERY. EXPECT SOME CLEARING THIS EVENING IN THE WAKE OF THE UPPER LOW...AND WITH CONTINUING HIGH BLYR MOISTURE FOG FORMATION IS AGAIN FAVORED TONIGHT. A MUCH STRONGER BOUNDARY WORKS THROUGH THE REGION ON TUESDAY. DECENT DYNAMICS AND RELATIVELY HIGH PWATS SHOULD TRIGGER HIGH COVERAGE SHOWERS AND A FEW THUNDERSTORMS ESPECIALLY OVER THE NORTHEAST WHERE CONDITIONS ARE MOST FAVORABLE. NORTHERLY SURFACE WINDS AND MUCH DRIER AIR FILTER IN BEHIND THE FRONT. INITIAL CAA BEHIND THE FRONT SHOULD INHIBIT AFTERNOON HIGH TEMPERATURES...WITH MANY LOCATIONS REACHING HIGHS FAIRLY EARLY...THEN HOLDING STEADY OR PERHAPS FALLING A COUPLE OF DEGREES IN THE AFTERNOON. && .AVIATION...GENERALLY VFR CONDITIONS THIS AFTERNOON WITH SCATTERED CONVECTION. IFR VSBYS AND CIGS DEVELOP AGAIN OVERNIGHT...NOT COMPLETELY DEPARTING UNTIL FROPA LATE TUESDAY MORNING. FROPA WILL SWING WINDS NW THEN N AND SCOUR OUT LOW CIGS AS DRIER AIR MOVES IN. && .MARINE...LIGHT TO MODERATE ONSHORE FLOW WILL CONTINUE OVERNIGHT WITH SEA FOG DEVELOPING. FLOW WILL RAPIDLY TURN OFFSHORE AND INCREASE...ESPECIALLY IN THE IMMEDIATE WAKE OF THE FRONTAL PASSAGE. FLOW SHOULD REMAIN ABOVE SCA CRITERIA THROUGH TUESDAY NIGHT. && .LONG TERM (WEDNESDAY THROUGH MONDAY)...ONSHORE FLOW WILL STRENGTHEN WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT AS A SURFACE CYCLONE DEEPENS OVER WEST TEXAS. BREEZY/WINDY CONDITIONS EXPECTED THURSDAY AFTERNOON/EVENING(POSSIBLY ADVISORY LEVELS) GIVEN SURFACE PRESSURE GRADIENT/ISALLOBARIC PRESSURE FALLS/THERMAL GRADIENT. TEMPERATURES WILL CLIMB TO ABOVE NORMAL LEVELS(ESPECIALLY THE COASTAL/RIO GRANDE PLAINS WHERE CLOUDINESS WILL BE LESS PREVALENT AND DRY TOPSOIL WILL BE MOST INFLUENTIAL). SCEC/SCA CONDITIONS WILL OCCUR MOST OF THE TIME OVER THE WATERS. A STRONG MID-LEVEL SHORTWAVE/CLOSED CYCLONE DIVES INTO TEXAS FRIDAY/SATURDAY. MODEL CONSENSUS/ENSEMBLES SUGGEST THE TROUGH AXIS WILL CLEAR THE REGION BY SATURDAY EVENING. HOWEVER...THE LATITUDINAL POSITION IS MORE UNCERTAIN AND WILL ULTIMATELY DICTATE HOW COLD THE AIRMASS WILL BE WHICH IS ORIGINATING FROM WESTERN CANADA. MODELS HAVE BEEN FLIP-FLOPPING WITH COLD FRONTAL TIMING FOR FRIDAY. PREFER THE FASTER 06Z GFS SOLUTION(CANADIAN/NOGAPS IN AGREEMENT) WHICH SWEEPS IT THROUGH DURING THE MORNING GIVEN DENSITY CONSIDERATIONS. MAINTAINED SLIGHT CHANCE POPS WEST TO MID-GRADE CHANCE POPS EAST AS MOISTURE IS SOMEWHAT LACKING AND CAPPING INVERSION IS PRESENT. RETAINED SLIGHT CHANCE POPS WEST AND LOW-END CHANCE POPS EAST FRIDAY NIGHT/SATURDAY AS SIGNIFICANT DYNAMICS OCCURS IN THE MIDST OF AT LEAST SUFFICIENT MID-LEVEL MOISTURE. POST-FRONTAL WINDY/STRONG SCA CONDITIONS EXPECTED GIVEN STRONG ISALLOBARIC PRESSURE RISES/COLD THERMAL ADVECTION. A WIND ADVISORY WILL PROBABLY BE REQUIRED AND THE OFFSHORE WATERS MAY FLIRT WITH GALE WARNING CRITERIA. A SURFACE ANTICYCLONE BUILDS IN SATURDAY NIGHT THEN QUICKLY RETREATS SUNDAY...FOLLOWED BY A DRY RE-ENFORCING COLD FRONT SUNDAY NIGHT. POST-FRONTAL TEMPERATURES WERE WEIGHTED TOWARD THE RAW GFS NUMBERS. MAINTAINED THE RAPID TEMPERATURE RECOVERY SUNDAY AS SIGNIFICANT WARM THERMAL ADVECTION FLOODS THE AREA WITH THE GROUND STILL RELATIVELY DRY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 62 82 44 68 52 / 10 50 10 0 10 VICTORIA 61 72 42 67 49 / 20 60 10 0 10 LAREDO 64 82 44 73 52 / 10 20 10 0 10 ALICE 61 83 41 71 50 / 10 40 10 0 10 ROCKPORT 64 74 47 66 54 / 10 60 10 0 10 COTULLA 61 72 40 70 50 / 10 20 10 0 10 KINGSVILLE 62 84 42 70 50 / 10 40 10 0 10 NAVY CORPUS 65 80 51 66 54 / 10 50 10 0 10 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ JV/71...SHORT TERM BB/85...LONG TERM tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1145 PM CST SUN FEB 10 2008 .AVIATION... COLD FRONT IS CURRENTLY DRAPED ACROSS THE NORTHERN TAF SITES AND WILL CONTINUE A GRADUAL PUSH SW. WILL SHOW WINDS NNE AT 5KT FOR THE NEXT FEW HOURS...WITH A MENTION OF LLWS AS SOUTH WINDS AT 1000FT ARE IN EXCESS OF 20KT AND WILL BE INCREASING DURING THE NEXT COUPLE HOURS. WINDS WILL GRADUALLY VEER AROUND TO THE EAST AND THEN SOUTH BY SUNRISE AS FRONT RETREATS NORTHWARD. MEANWHILE...STRATUS WILL BE MOVING UP FROM THE SOUTH AND EXPECT IT TO ARRIVE AT KACT AROUND 8Z AND IN THE METROPLEX AROUND 10Z. SOME IFR CIGS WILL BE POSSIBLE AS INITIAL STRATUS LAYER MOVES IN AND MIXES WITH/SATURATES THE VERY SHALLOW FRONTAL INVERSION. WILL SHOW MVFR CIGS PREVAILING AT ALL TAF SITES THROUGH MID AFTERNOON WITH CIGS LIFTING/SCATTERING OUT THEREAFTER. BROUGHT A MENTION OF TSRA AND FROPA AT 4Z FOR METROPLEX SITES...AND LATER SHIFTS CAN REFINE THIS THINKING. TR.92 && .UPDATE... COLD FRONT HAS SAGGED FARTHER SOUTH THAN PREVIOUSLY THOUGHT AND FORECAST AND CONTINUES TO MOVE SOUTH. THE FRONT NOW LIES JUST SOUTH OF A LINE FROM COOPER...TO MCKINNEY...TO DECATUR...TO NEWPORT. RUC13 APPEARS TO BE HANDLING THE FRONT THE BEST...INSTEAD OF THE NEW NAM...SO WILL BRING THE FRONT AS FAR SOUTH AS THE METROPLEX AND STALL IT THERE BEFORE IT PUSHES BACK NORTH AS A WARM FRONT CLOSER TO DAYBREAK. THIS MEANS COLDER TEMPERATURES ARE EXPECTED OVERNIGHT ALONG AND NORTH OF INTERSTATE 20. HAVE LOWERED OVERNIGHT LOWS IN THIS AREA BY 5-8 DEGREES WITH VALUES RANGING FROM THE UPPER 30S ALONG THE RED RIVER TO THE MID 40S ALONG INTERSTATE 20. OVERNIGHT LOWS IN THE LOWER TO MID 50S CAN STILL BE EXPECTED SOUTH OF I-20. HAVE ALSO REMOVED POPS FROM THE FAR NORTHERN COUNTIES AFTER MIDNIGHT. APPEARS THE BEST ENERGY AND DYNAMICS WILL STILL BE UP IN COLORADO AND OKLAHOMA AND WILL NOT MAKE IT TO THE RED RIVER UNTIL AFTER SUNRISE. HOWEVER...A FEW AREAS OF DRIZZLE ARE POSSIBLE ALONG THE RED RIVER AROUND SUNRISE. OTHER CHANGES TO GRIDS WERE TO UPDATE BASED ON CURRENT TRENDS. NEW MODEL DATA INDICATES FRONT TOMORROW EVENING MAY ARRIVE A FEW HOURS EARLIER AND BEGIN ENTERING NORTH TEXAS AROUND SUNSET. 82/JLD && DISCUSSION... THE COMING WEEK WILL BE REPLETE WITH WEATHER ACTIVITY IN NORTH TEXAS. THE FIRST UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE AREA TONIGHT AND MONDAY...WITH THE CHANCE FOR RAINFALL AND A FEW THUNDERSTORMS..THROUGH TUESDAY AFTERNOON. SOME BENEFICIAL RAIN WILL OCCUR WITH THIS SYSTEM. THE SECOND...AND LAST...SYSTEM WILL MOVE ACROSS THE AREA FROM EARLY THURSDAY THROUGH SATURDAY...PRODUCING MAINLY LIGHT RAIN. THERE ARE LOW CHANCES OF SOME WINTRY PRECIPITATION...MAINLY NEAR THE RED RIVER...BUT IT IS TOO EARLY TO DO ANYTHING RATHER THEN SPECULATE ABOUT THE WINTRY WEATHER AT THE CURRENT TIME. MOREOVER...THE MODELS` OVERALL TREATMENT OF WINTRY WEATHER THIS WINTER HAS BEEN MARGINAL AT BEST...AND USUALLY LOUSY. THUS...AT THE CURRENT TIME WE HAVE FORECASTED RAIN ONLY WITH THE SECOND SYSTEM AT THE END OF THE WEEK. TEMPERATURES WILL RUN FROM MILD TO COOL THROUGHOUT THE WEEK. #26 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 45 66 48 58 33 / 10 40 50 20 5 WACO, TX 53 69 52 61 36 / 10 20 30 50 5 PARIS, TX 38 56 46 55 30 / 10 50 70 50 10 DENTON, TX 40 66 46 59 28 / 10 40 50 20 5 MCKINNEY, TX 40 63 46 57 30 / 10 50 60 30 5 DALLAS, TX 46 65 47 56 37 / 10 40 50 30 5 TERRELL, TX 50 64 49 56 34 / 10 40 50 50 5 CORSICANA, TX 51 66 50 58 35 / 10 30 40 50 10 TEMPLE, TX 54 69 51 63 35 / 10 20 30 50 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 92/82 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LUBBOCK TX 1044 PM CST SUN FEB 10 2008 .UPDATE... COLD FRONT NEARLY BISECTING FORECAST AREA FROM NORTHWEST TO NORTHEAST AND IS EXPECTED TO CONTINUE SLIDING SLIGHTLY TO THE SOUTHWEST DURING THE EARLY MORNING HOURS...BEFORE MOVING BACK TO THE NORTHEAST LATER THIS MORNING AS LEE SIDE TROUGH DEVELOPS OVER EASTERN NEW MEXICO. TEMPERATURES OVER SOUTHEASTERN TEXAS PANHANDLE HAVE DROPPED TO BELOW FORECAST VALUES ATTM AND WILL UPDATE TO REFLECT CURRENT TRENDS. SOME LOW CLOUDS ARE DEVELOPING OVER SOUTHEAST ZONES...HOWEVER NOT AS MUCH AS DEPICTED IN GRIDS. HAVE ALSO UPDATED DEW POINT TEMPERATURES AND SKY CONDITION. && .PREV DISCUSSION... /ISSUED 324 PM CST SUN FEB 10 2008/ SHORT TERM... EARLY THIS AFTERNOON...A COLD FRONT WAS CONTINUING TO BACKDOOR DOWN INTO THE AREA FROM THE NORTHEAST...WITH WINDS SHIFTING TO THE ENE OVER THE EXTREME NORTHEAST ZONES AS OF 20Z. THIS SHALLOW COOL AIR SHOULD CONTINUE TO BACKDOOR THROUGH MOST LOCATIONS OFF THE CAPROCK THROUGH THE REMAINDER OF THE AFTERNOON. IT REMAINS UNCERTAIN EXACTLY HOW FAR WEST THIS FRONT WILL GET TONIGHT...BUT THE 12Z WRF-NAM AND 15Z RUC DATA SUGGEST A DIMMITT TO LUBBOCK LINE AS A GOOD GUESS...AND HAVE GONE WITH THAT IN THE GRIDS. HOWEVER...THESE SHALLOW FRONTS ARE TRICKY AND IT COULD WELL MOVE EVEN FARTHER WEST YET /AS 18Z RUC NOW INDICATES/. ADDITIONALLY...WEST OF THE FRONT SOUTHERLY WINDS /THANKS TO A LEE TROUGH IN EASTERN NM/ HAVE BEEN ABLE TO TRANSPORT SOME MUCH IMPROVED LOW LEVEL MOISTURE INTO THE SOUTHERN SOUTH PLAINS...WITH DEWPOINTS WELL INTO THE 40S NOTED OVER THE SE HALF OF THE SOUTH PLAINS AROUND 20Z. THIS MOISTURE WILL CONTINUE TO STREAM NORTH THROUGH THE NIGHT IN WAA REGIME...WITH LOW CLOUDS A GOOD BET OVER MOST OF THE AREA. THERE COULD ALSO BE SOME PATCHY FOG FOR LOCATIONS ON THE CAPROCK. OTHER CONCERN TONIGHT IS THE POSSIBILITY OF SOME SHOWERS AS MOISTURE INTERACTS WITH THE FRONT. MODEL DATA SUGGESTS SOME WEAK AMOUNTS OF MUCAPE AVAILABLE GIVEN STEEP MID-LEVEL LAPSE RATES ABOVE RELATIVELY SHALLOW MOISTURE. THUS...COULD NOT RULE OUT A SHOWER OVER THE EASTERN SOUTH PLAINS OR ROLLING PLAINS...BUT SREF DATA SUGGESTS THAT THE SHALLOW NATURE OF THE MOISTURE AND LIMITED LIFT WILL KEEP PRECIP CHANCES RATHER LOW /BELOW 15 PERCENT/. THUS...HAVE KEPT MENTION OUT OF THE FORECAST...BUT EVENING SHIFT WILL HAVE TO WATCH. WINDS WILL QUICKLY VEER AROUND TO THE SOUTHWEST AS A SURFACE LOW BECOMES ESTABLISHED SOMEWHERE NEAR THE SOUTHWEST PANHANDLE EARLY MONDAY. THIS WILL SWEEP THE BETTER MOISTURE EASTWARD...THOUGH POSSIBLY LINGERING OVER THE ROLLING PLAINS THROUGH THE DAY. TEMPERATURES SHOULD BE RELATIVELY MILD TONIGHT WITH IMPROVED MOISTURE AND EXPECTED LOW CLOUDS. THEN...TEMPERATURES SHOULD REBOUND INTO THE 70S FOR MOST LOCATIONS ON THE CAPROCK MONDAY AS DOWNSLOPE WINDS AND DRIER AIR QUICKLY RETURNS. HIGHS ARE MORE IN QUESTION ACROSS THE NORTHEAST ZONES WHERE THE COOLER AIR/LOW CLOUDS WILL BE MORE DIFFICULT TO ERODE. THUS...HAVE GONE WITH THE LOW END OF GUIDANCE FOR FORECAST HIGHS THERE. LONG TERM... STILL THINK THAT FRONTAL PASSAGE INTO RELATIVELY MOIST AIR MONDAY NIGHT COULD SET OFF A FEW SHOWERS/THUNDRESTORMS AS FAR WEST AS THE ERN ZONES OF THE FCST AREA...ALTHOUGH POSSIBILITY IS STILL PRETTY REMOTE. ATTENTION THEN TURNS TO THE THURSDAY THROUGH SATURDAY TIME FRAME WHEN THE NEXT UPPER SYSTEM IS PROGGED TO AFFECT THE AREA. MODELS ARE IN REASONABLE AGREEMENT WITH THE INITIAL EVOLUTION OF THE TROUGH AS IT MOVES ACROSS THE WRN CONUS...SPLITTING THE UPPER LEVEL FLOW WITH THE SRN END BECOMING A CLOSED LOW OVER THE 4-CORNERS REGION THURSDAY. UNFORTUNATELY SIGNIFICANT DIFFERENCES ARISE WITH ITS GENERAL EASTWARD PROGRESSION FROM THERE. 12Z GFS HAS TRENDED TOWARD A FAIRLY FAST MOVING OPENING WAVE AS IT CROSSES THE REGION WITH WEAKENING DYNAMICS AND A BRIEF SHOT AT PRECIPITATION THURSDAY NIGHT INTO FRIDAY. LATEST ECMWF CONTINUES DECENT RUN-TO-RUN CONSISTENCY WITH A CLOSED LOW MOVING MORE SLOWLY ACROSS THE REGION AND BRINGING A BETTER SHOT OF PRECIP FRIDAY INTO FRIDAY NIGHT. 12Z CANADIAN IS SLOWER LIKE THE ECMWF BUT WITH AN OPEN TROUGH SIMILAR TO THE GFS. 12Z GFS ENSEMBLE MEMBERS SUPPORT THE GAMUT OF SOLUTIONS WITH A MAJORITY TENDING TO FAVOR ITS OPERATIONAL SOLUTION. THUS STILL QUITE A BIT OF UNCERTAINTY AS IS OFTEN THE CASE WITH THESE CLOSED LOWS IN SPLIT FLOW SCENARIOS. DO NOT HAVE A STRONG CASE TO MAKE ANY WHICH WAY. AS SUCH WILL HANG ONTO SLIGHT CHC POPS IN THIS TIME FRAME COVERING POSSIBLITY OF FASTER BUT ALSO SOME SLOWER SOLUTIONS. WILL REMOVE PPS FROM SATURDAY IN PART TO KEEP MENTION OF PRECIP CONFINED TO THREE PERIODS BUT ALSO BECAUSE ONLY THE SLOWEST MODELS/MEMBERS SUPPORT THAT TIMING. THIS RUN HAS ALSO TRENDED TO KEEPING PRECIP MORE WITH THE LOW ITSELF WHICH WOULD TEND TO FAVOR SNOW OVER FREEZING RAIN. WILL KEEP MENTION OF THE LATTER IN ATTM BUT IS SOMETHING TO KEEP AN EYE ON. LATE WEEK ARCTIC INTRUSION STILL LOOKS COLDER THAN GUIDANCE SUGGESTS AND HAVE UNDERCUT THOSE NUMBERS...PARTICULARLY THURSDAY AND FRIDAY. FIRE WEATHER... AFTER IMPROVED LOW LEVEL MOISTURE THIS AFTERNOON AND TONIGHT...IT APPEARS VERY DRY AIR WILL AGAIN FILTER INTO THE SOUTHWEST PANHANDLE AND WESTERN SOUTH PLAINS MONDAY AFTERNOON. HOWEVER...ALTHOUGH BREEZY....FORECAST WIND SPEEDS CURRENTLY FALL SHORT OF CRITICAL FIRE WEATHER CRITERIA. WEDNESDAY LOOKS BREEZY AS WELL...PARTICULARLY WRN ZONES. HOWEVER FOR THIS DAY FCST RH VALUES ARE ALSO MARGINAL. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 33 68 29 54 29 / 0 0 10 0 0 TULIA 36 70 30 53 28 / 10 0 10 0 0 PLAINVIEW 40 71 30 52 29 / 10 0 10 0 0 LEVELLAND 47 72 30 54 28 / 10 0 10 0 0 LUBBOCK 45 72 31 55 29 / 10 0 10 0 0 DENVER CITY 46 70 33 55 31 / 10 0 10 0 0 BROWNFIELD 47 72 31 55 30 / 10 0 10 0 0 CHILDRESS 32 64 32 53 30 / 10 10 20 0 0 SPUR 41 72 33 56 30 / 10 10 20 0 0 ASPERMONT 41 72 35 56 30 / 10 10 20 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 08 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREEN BAY WI 1001 PM CST MON FEB 11 2008 .UPDATE...DECIDED TO ISSUE A LAKE-EFFECT SNOW ADVISORY FOR DOOR... KEWAUNEE AND MANITOWOC COUNTIES TONIGHT INTO TUESDAY. MODELS... ASIDE THE RUC...ARE NOT HANDLING THIS SITUATION VERY WELL...AS LAKE-EFFECT SNOW SHOWERS HAVE DEVELOPED EARLIER THAN ANTICIPATED... AND A WELL DEFINED MESO-LOW IS ALREADY ORGANIZING OVER CNTRL LAKE MICHIGAN. LLVL WINDS ARE FCST TO BECOME UNIDIRECTIONAL FROM AN ESE DIRECTION OVERNIGHT...AND CONTINUE INTO TUESDAY. A STG LLVL CONVERGENCE ZONE WILL GET LOCKED IN ALONG THE LKSHR...AND WILL BE ENHANCED BY THE VERY COLD TEMPERATURES THAT ARE OCCURING INLAND. INSTABILITY IS DECENT...WITH LAKE-H8 DELTA-T`S OF 17-19 C. LAKE EFFECT SNOW WILL BE ENHANCED BY THE S/W TROF MOVG THROUGH THE AREA LATE TONIGHT INTO TUESDAY. LES CHARTS INDICATE A GOOD POTENTIAL FOR 3-5 INCHES/12 HOUR PERIOD...SO WILL START WITH TOTALS OF 4-7 INCHES IN KEWAUNEE/MANITOWOC COUNTIES...WHICH WILL BE AFFECTED BY THE MESO-LOW SHORTLY AFTER MIDNIGHT...AND WILL RECEIVE THE BEST ENHANCEMENT DUE TO THE S/W TROF ON TUES. WILL MENTION SLIGHTLY LOWER AMOUNTS FOR DOOR COUNTY. HAVE A GUT FEELING THAT THE MIDNIGHT SHIFT MAY BE UPGRADING PART OF THIS TO A WARNING LATER TONIGHT. KIECKBUSCH && .PREV DISCUSSION...ISSUED AT 343 PM CST MON FEB 11 2008... SHORT TERM...TONITE AND TUESDAY...FORECAST FOCUS ON TEMPERATURES AND SNOW CHANCES. THE LOW PRESSURE SYSTEM...AND ASSOCIATED BAND OF SNOW HAVE SLOWED IN THEIR NORTHWARD PROGRESSION TODAY. GIVEN THE MOSTLY CLEAR SKIES EXPECTED TO CONTINUE INTO THE EVENING HOURS WILL LOWER MINS TO THE MAV VALUES AS RECENT TRENDS HAVE BEEN COLDER AND CLOSER TO THE MAV. WITH THE SLOWER SNOW PROGRESSION...THE BULK OF THE SYNOPTIC SNOW WILL NOT REACH THE CWA UNTIL AFTER MIDNIGHT. ACROSS THE LAKE MICHIGAN LAKESHORE COUNTIES WINDS BECOME CONDUCIVE FOR LAKE EFFECT WITH AN EASTERLY FETCH ACROSS LAKE MICHIGAN SHORTLY AFTER MIDNITE. DESPITE FAVORABLE DELTA T VALUES IN THE UPPER TEENS...THE AMOUNT OF LAKE EFFECT WILL BE LIMITED BY THE 90 MILE FETCH ACROSS THE LAKE. GIVEN THIS TIMING WILL ADJUST POPS TO BE HIGHEST LATE TONIGHT AND EARLY TUESDAY MORNING...BEFORE THE LOW MOVES TO THE EAST AND WINDS BECOME NORTHWESTERLY TUESDAY AFTERNOON. AT THIS TIME THE BULK OF THE SNOW LOOKS TO BE ACROSS THE SOUTHEAST CWA WHERE AROUND 3 INCHES OF SNOW COULD FALL IN 18 HOURS...BELOW SNOW ADVISORY CRITERIA. NORTHERN WISCONSIN WILL SEE THE LEAST SNOW AND WILL PROBABLY NOT GET MORE THAN A DUSTING...IF ANY SNOW AT ALL. LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. POTENTIAL SNOWSTORM FOR THURSDAY IS THE CHIEF WEATHER MAKER FOR THIS PERIOD. UPPER TROUGH APPROACHING BRITISH COLUMBIA COAST THIS AFTERNOON IS FORECAST BY THE MODELS TO DROP SOUTHEAST TONIGHT AND TUESDAY. THE JET ENERGY IS FORECAST TO SPLIT WITH SOME MOVING ACROSS THE NORTHERN PLAINS AND SOME HEADED TOWARDS THE DESERT SOUTHWEST. THE ECMWF HAS BEEN VERY CONSISTENT WITH THIS SYSTEM FOR THE PAST THREE DAYS...AND THE 12 UTC GFS NOW HAS A SIMILAR FORECAST. LIGHT SNOW SHOULD ARRIVE IN CENTRAL WISCONSIN WEDNESDAY NIGHT...WITH MODERATE SNOW EXPECTED ACROSS THE ENTIRE REGION THURSDAY. ANOTHER SYSTEM MIGHT BRING SOME SNOW SATURDAY NIGHT AND SUNDAY...THOUGH THE BEST DYNAMICS LOOK TO BE NORTH OF WISCONSIN. SMALL CHANCE OF LAKE EFFECT SNOW SHOWERS FROM LAKE SUPERIOR WEDNESDAY AND FRIDAY...BUT WINDS NOT IDEAL AND HIGH RESOLUTION MODIS VISIBLE SATELLITE PICTURES AVAILABLE AT HTTP://COASTWATCH.GLERL.NOAA.GOV/MODIS/MODIS.CGI/MODIS?REGION=M&PAGE=1 SHOW THAT THE WESTERN FOURTH OF LAKE SUPERIOR IS ICING UP. SO LAKE EFFECT POTENTIAL IS SMALL FOR NOW. AVIATION...VFR CONDITIONS EXPECTED THIS EVENING...WITH CONDITIONS LOWERING TO MVFR SOUTH TO NORTH TONIGHT AS AREA OF LIGHT SNOW MOVES NORTH. MVFR CONDITIONS EXPECTED TO LAST INTO TUESDAY AS LIGHT SNOW SLOWLY ENDS FROM WEST TO EAST. && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 4 PM CST TUESDAY FOR WIZ022-040- 050. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 141 PM CST MON FEB 11 2008 .UPDATE...BASED ON LATEST MODEL GUIDANCE...ALONG WITH CURRENT RADAR TRENDS...HAVE DELAYED SNOW ADVISORY FOR AREAS AROUND KLSE AND POINTS EAST UNTIL 00Z THIS EVENING. MAINTAINED START TIME OF 21Z THIS AFTERNOON FOR SNOW ADVISORY IN LOCATIONS OVER MUCH OF SOUTHEAST MN AND NORTHEAST IOWA. ALSO CHOSE TO EXTEND ADVISORY UNTIL 18Z TUESDAY. IN ADDITION...OPTED TO DISCONTINUE SNOW ADVISORY FOR AREAS FROM MNZ079 THROUGH WIZ032>034. PLEASE REFERENCE HEADLINE CHANGES BELOW. THOMPSON && .PREV DISCUSSION... /ISSUED 1034 AM CST MON FEB 11 2008/ UPDATE...RADAR AND SURFACE OBSERVATIONS INDICATED SNOW OCCURRING IN THE FORECAST AREA MAINLY WEST OF THE MISSISSIPPI RIVER. IN FACT...HEAVIER SNOW BAND ASSOCIATED WITH MID LEVEL FRONTOGENESIS AND NEGATIVE EPV WAS SITUATED FROM KMCW...KCCY...KOLZ...KDBQ. CALLS TO OBSERVERS INDICATED AMOUNTS AROUND A HALF OF AN INCH AS OF 15Z...WHICH WERE ISSUED IN PUBLIC INFORMATION STATEMENT AT 1523Z. LATEST RUC AND NAM/WRF SUGGEST FRONTOGENETIC FORCING SHIFTS SOUTHWARD GRADUALLY THROUGH 18Z...THUS SNOW SHOULD DIMINISH IN INTENSITY BUT NOT BEFORE HIGHEST ACCUMULATIONS OF 1 TO 2 INCHES OCCUR IN AFOREMENTIONED CORRIDOR ACROSS NORTHEAST IOWA. DATA BASE AND ASSOCIATED TEXT AND GRAPHIC INFORMATION HAS BEEN UPDATED. ANOTHER INTERMEDIATE UPDATE WILL PROBABLY BE FORTHCOMING BETWEEN 1700-1730Z TO INCLUDE TRENDS EXPECTED FOR THIS AFTERNOON. THOMPSON && PREV DISCUSSION... /ISSUED 257 AM CST MON FEB 11 2008/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT MAIN FORECAST CONCERN IS ON SNOW CHANCES AND AMOUNTS TODAY THROUGH TONIGHT. 07Z SURFACE ANALYSIS SHOWS HIGH PRESSURE EXTENDING FROM NEAR LAKE WINNIPEG THROUGH WESTERN WISCONSIN AND INTO CENTRAL ILLINOIS. INFRARED SATELLITE IMAGERY SHOWING WARM ADVECTION MID LEVEL CLOUDS ON THE BACK SIDE OF THE HIGH ACROSS SOUTHER MINNESOTA AND MOST OF IOWA. MEANWHILE...WATER VAPOR IMAGERY IS SHOWING SHORTWAVE DROPPING SOUTHEAST THROUGH MONTANA THAT WILL BE THE MAIN WEATHER PLAYER LATER TODAY. 11.00Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD AS PROGRESSIVE FLOW CONTINUES ACROSS THE AREA. THUS THE ACTIVE WEATHER PATTERN WILL CONTINUE. FOR TODAY EXPECT SHORTWAVE TO DROP SOUTHEAST ACROSS THE AREA THIS AFTERNOON. DRIER LOW LEVEL AIR THIS MORNING HAS KEPT SNOW WELL OFF TO THE WEST OF THE AREA. MODELS INDICATE SATURATION TO OCCUR FROM WEST TO EAST THIS AFTERNOON. POTENTIAL VORTICITY ADVECTION/850MB- 700MB WARM ADVECTION/280K-290K ISENTROPIC LIFT ALL COINCIDE ACROSS THE AREA FROM MID AFTERNOON THROUGH TONIGHT ACROSS THE AREA TO PROVIDE A BROAD AREA OF LIFT. IN ADDITION SOUTHERN PORTIONS OF THE FORECAST AREA WILL BE IN THE LEFT EXIT REGION OF A 300MB JET OVER IOWA WITH UPPER LEVEL DIVERGENCE OVER THIS AREA. THIS WILL AID IN THE LIFT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA ENHANCING SNOWFALL AMOUNTS. WITH THE COLD TEMPERATURES SNOW RATIOS WILL BECOME A FACTOR. COBB DATA FROM BOTH THE NAM AND GFS SHOWING AVERAGE RATIOS AROUND 18:1 AND USED THIS FOR THE SNOWFALL AMOUNTS. THIS WILL HAVE TO BE MONITORED TODAY AS ANY HIGHER RATIOS COULD PUSH AMOUNTS OVER 6 INCHES ACROSS PORTIONS OF THE AREA. FOR NOW GENERAL 2 TO 6 INCHES EXPECTED ACROSS THE AREA. AFTER COLLABORATION WITH SURROUNDING OFFICES WILL HOIST A SNOW ADVISORY GENERALLY SOUTH OF A LINE FROM LAKE CITY MINNESOTA...TO BLACK RIVER FALLS LINE. ON TUESDAY SYSTEMS EXITS QUICKLY TO THE EAST WITH HIGH PRESSURE DROPPING ACROSS THE AREA. MAINTAINED LOWER END POPS ACROSS THE EAST DURING THE MORNING HOURS. DRY HIGH PRESSURE THEN SETTLES IN TUESDAY NIGHT WITH QUIET WEATHER. GUIDANCE TEMPERATURES HAVE BEEN COMING IN COOLER BEHIND WAVE TONIGHT AND THUS AFTER COLLABORATION WITH SURROUNDING OFFICES DID LOWER TEMPERATURES FOR TUESDAY AND TUESDAY NIGHT. LONG TERM...WEDNESDAY THROUGH SUNDAY YET ANOTHER WAVE IN THIS PROGRESSIVE PATTERN BRINGS ANOTHER SHOT OF ACCUMULATING SNOW TO THE AREA WEDNESDAY THROUGH THURSDAY NIGHT. MODEL TRENDS HAVE BEEN FURTHER NORTH WITH THIS WITH THE HEAVIER BAND OF QPF ACROSS ABOUT THE NORTHERN HALF OF THE FORECAST AREA. CURRENT GRIDS HAVE THIS WELL IN HAND WITH THE BETTER CHANCES FOR ACCUMULATING SNOWS COMING WEDNESDAY NIGHT AND THURSDAY. 11.00Z GFS AND ECMWF DIFFER WITH HANDLING OF NEXT FRONT ON THE WEEKEND. WITH THESE DIFFERENCES NO CHANGES WILL BE MADE TO THE GRIDS WITH LOW END POPS SATURDAY AND SATURDAY NIGHT LOOKING GOOD. && AVIATION... A SHORTWAVE TROUGH WILL PUSH EAST INTO THE REGION BY TONIGHT...SPINNING EAST EARLY TUESDAY MORNING. CLOUDS WILL THICKEN AND CEILINGS WILL LOWER TODAY AS RESULT...WITH MVFR CEILINGS LIKELY MOVING BY OR AROUND 00Z. -SN WILL ALSO DEVELOP...BECOMING PREDOMINANT AFTER 00Z AND CONTINUING FOR MUCH OF TONIGHT. AN ACCOMPANYING DROP IN VSBYS INTO THE 1-2SM RANGE WITH THE SNOW CAN BE EXPECTED...WITH SOME 1/2SM NOT OUT OF THE QUESTION. WINDS WILL BE LIGHTER...SO DON/T EXPECT BLSN CONCERNS FOR KRST...DESPITE WHAT SHOULD BE A RATHER FLUFFY...HIGH RATIO SNOW. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...SNOW ADVISORY 3 PM THIS AFTERNOON UNTIL 12 PM CST TUESDAY FOR WIZ054-WIZ061. SNOW ADVISORY FROM 6 PM THIS EVENING TO 12 PM CST TUESDAY FOR WIZ041-WIZ042-WIZ043-WIZ044-WIZ053-WIZ055. MN...SNOW ADVISORY 3 PM THIS AFTERNOON UNTIL 12 PM CST TUESDAY FOR MNZ086-MNZ087-MNZ094-MNZ095. SNOW ADVISORY FROM 6 PM THIS EVENING TO 12 PM CST TUESDAY FOR MNZ088-MNZ096. IA...SNOW ADVISORY 3 PM THIS AFTERNOON UNTIL 12 PM CST TUESDAY FOR IAZ008-IAZ009-IAZ010-IAZ011-IAZ018-IAZ019-IAZ029-IAZ030. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1034 AM CST MON FEB 11 2008 .UPDATE...RADAR AND SURFACE OBSERVATIONS INDICATED SNOW OCCURRING IN THE FORECAST AREA MAINLY WEST OF THE MISSISSIPPI RIVER. IN FACT...HEAVIER SNOW BAND ASSOCIATED WITH MID LEVEL FRONTOGENESIS AND NEGATIVE EPV WAS SITUATED FROM KMCW...KCCY...KOLZ...KDBQ. CALLS TO OBSERVERS INDICATED AMOUNTS AROUND A HALF OF AN INCH AS OF 15Z...WHICH WERE ISSUED IN PUBLIC INFORMATION STATEMENT AT 1523Z. LATEST RUC AND NAM/WRF SUGGEST FRONTOGENETIC FORCING SHIFTS SOUTHWARD GRADUALLY THROUGH 18Z...THUS SNOW SHOULD DIMINISH IN INTENSITY BUT NOT BEFORE HIGHEST ACCUMULATIONS OF 1 TO 2 INCHES OCCUR IN AFOREMENTIONED CORRIDOR ACROSS NORTHEAST IOWA. DATA BASE AND ASSOCIATED TEXT AND GRAPHIC INFORMATION HAS BEEN UPDATED. ANOTHER INTERMEDIATE UPDATE WILL PROBABLY BE FORTHCOMING BETWEEN 1700-1730Z TO INCLUDE TRENDS EXPECTED FOR THIS AFTERNOON. THOMPSON && .PREV DISCUSSION... /ISSUED 257 AM CST MON FEB 11 2008/ SHORT TERM...TODAY THROUGH TUESDAY NIGHT MAIN FORECAST CONCERN IS ON SNOW CHANCES AND AMOUNTS TODAY THROUGH TONIGHT. 07Z SURFACE ANALYSIS SHOWS HIGH PRESSURE EXTENDING FROM NEAR LAKE WINNIPEG THROUGH WESTERN WISCONSIN AND INTO CENTRAL ILLINOIS. INFRARED SATELLITE IMAGERY SHOWING WARM ADVECTION MID LEVEL CLOUDS ON THE BACK SIDE OF THE HIGH ACROSS SOUTHER MINNESOTA AND MOST OF IOWA. MEANWHILE...WATER VAPOR IMAGERY IS SHOWING SHORTWAVE DROPPING SOUTHEAST THROUGH MONTANA THAT WILL BE THE MAIN WEATHER PLAYER LATER TODAY. 11.00Z MODELS IN GOOD AGREEMENT THROUGH THE PERIOD AS PROGRESSIVE FLOW CONTINUES ACROSS THE AREA. THUS THE ACTIVE WEATHER PATTERN WILL CONTINUE. FOR TODAY EXPECT SHORTWAVE TO DROP SOUTHEAST ACROSS THE AREA THIS AFTERNOON. DRIER LOW LEVEL AIR THIS MORNING HAS KEPT SNOW WELL OFF TO THE WEST OF THE AREA. MODELS INDICATE SATURATION TO OCCUR FROM WEST TO EAST THIS AFTERNOON. POTENTIAL VORTICITY ADVECTION/850MB- 700MB WARM ADVECTION/280K-290K ISENTROPIC LIFT ALL COINCIDE ACROSS THE AREA FROM MID AFTERNOON THROUGH TONIGHT ACROSS THE AREA TO PROVIDE A BROAD AREA OF LIFT. IN ADDITION SOUTHERN PORTIONS OF THE FORECAST AREA WILL BE IN THE LEFT EXIT REGION OF A 300MB JET OVER IOWA WITH UPPER LEVEL DIVERGENCE OVER THIS AREA. THIS WILL AID IN THE LIFT ACROSS THE SOUTHERN HALF OF THE FORECAST AREA ENHANCING SNOWFALL AMOUNTS. WITH THE COLD TEMPERATURES SNOW RATIOS WILL BECOME A FACTOR. COBB DATA FROM BOTH THE NAM AND GFS SHOWING AVERAGE RATIOS AROUND 18:1 AND USED THIS FOR THE SNOWFALL AMOUNTS. THIS WILL HAVE TO BE MONITORED TODAY AS ANY HIGHER RATIOS COULD PUSH AMOUNTS OVER 6 INCHES ACROSS PORTIONS OF THE AREA. FOR NOW GENERAL 2 TO 6 INCHES EXPECTED ACROSS THE AREA. AFTER COLLABORATION WITH SURROUNDING OFFICES WILL HOIST A SNOW ADVISORY GENERALLY SOUTH OF A LINE FROM LAKE CITY MINNESOTA...TO BLACK RIVER FALLS LINE. ON TUESDAY SYSTEMS EXITS QUICKLY TO THE EAST WITH HIGH PRESSURE DROPPING ACROSS THE AREA. MAINTAINED LOWER END POPS ACROSS THE EAST DURING THE MORNING HOURS. DRY HIGH PRESSURE THEN SETTLES IN TUESDAY NIGHT WITH QUIET WEATHER. GUIDANCE TEMPERATURES HAVE BEEN COMING IN COOLER BEHIND WAVE TONIGHT AND THUS AFTER COLLABORATION WITH SURROUNDING OFFICES DID LOWER TEMPERATURES FOR TUESDAY AND TUESDAY NIGHT. LONG TERM...WEDNESDAY THROUGH SUNDAY YET ANOTHER WAVE IN THIS PROGRESSIVE PATTERN BRINGS ANOTHER SHOT OF ACCUMULATING SNOW TO THE AREA WEDNESDAY THROUGH THURSDAY NIGHT. MODEL TRENDS HAVE BEEN FURTHER NORTH WITH THIS WITH THE HEAVIER BAND OF QPF ACROSS ABOUT THE NORTHERN HALF OF THE FORECAST AREA. CURRENT GRIDS HAVE THIS WELL IN HAND WITH THE BETTER CHANCES FOR ACCUMULATING SNOWS COMING WEDNESDAY NIGHT AND THURSDAY. 11.00Z GFS AND ECMWF DIFFER WITH HANDLING OF NEXT FRONT ON THE WEEKEND. WITH THESE DIFFERENCES NO CHANGES WILL BE MADE TO THE GRIDS WITH LOW END POPS SATURDAY AND SATURDAY NIGHT LOOKING GOOD. && AVIATION... A SHORTWAVE TROUGH WILL PUSH EAST INTO THE REGION BY TONIGHT...SPINNING EAST EARLY TUESDAY MORNING. CLOUDS WILL THICKEN AND CEILINGS WILL LOWER TODAY AS RESULT...WITH MVFR CEILINGS LIKELY MOVING BY OR AROUND 00Z. -SN WILL ALSO DEVELOP...BECOMING PREDOMINANT AFTER 00Z AND CONTINUING FOR MUCH OF TONIGHT. AN ACCOMPANYING DROP IN VSBYS INTO THE 1-2SM RANGE WITH THE SNOW CAN BE EXPECTED...WITH SOME 1/2SM NOT OUT OF THE QUESTION. WINDS WILL BE LIGHTER...SO DON/T EXPECT BLSN CONCERNS FOR KRST...DESPITE WHAT SHOULD BE A RATHER FLUFFY...HIGH RATIO SNOW. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR WIZ032-WIZ033-WIZ034-WIZ041-WIZ042-WIZ043-WIZ044-WIZ053- WIZ054-WIZ055-WIZ061. MN...SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR MNZ079-MNZ086-MNZ087-MNZ088-MNZ094-MNZ095-MNZ096. IA...SNOW ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM CST TUESDAY FOR IAZ008-IAZ009-IAZ010-IAZ011-IAZ018-IAZ019-IAZ029-IAZ030. && $$ SHORT/LONG TERM....RABERDING AVIATION...........RIECK wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 441 AM EST WED FEB 13 2008 .SYNOPSIS... A WARM FRONT CURRENTLY JUST SOUTH OF LONG ISLAND...WILL WORK ITS WAY NORTHWEST THIS MORNING. IT WILL NOT MAKE IT COMPLETELY THROUGH THE REGION...AS LOW PRESSURE CONSOLIDATES INTO A SINGLE COASTAL LOW JUST OFF THE DELMARVA PENINSULA BY EARLY AFTERNOON. THIS LOW WILL THEN LIFT NORTHEAST TO THE CANADIAN MARITIME PROVINCES BY THURSDAY MORNING. A WEAK SECONDARY WILL DEVELOP NEAR THE VIRGINIA CAPES THIS EVENING...AND TRACK WELL TO OUR SOUTHEAST OVERNIGHT. WEAK HIGH PRESSURE BUILDS INTO OUR SOUTH THURSDAY AND THURSDAY NIGHT. A COLD FRONT APPROACHES FROM THE NORTHWEST FRIDAY MORNING...THEN CROSSES THE TRI-STATE FRIDAY AFTERNOON AND EVENING. HIGH PRESSURE BUILDS IN FROM THE WEST LATE FRIDAY NIGHT AND SATURDAY...THEN MOVES OFFSHORE SATURDAY NIGHT. AN AREA OF LOW PRESSURE WILL MOVE FROM THE GULF COAST STATES SUNDAY MORNING...TO THE VICINITY OF SOUTHERN NEW ENGLAND BY MONDAY MORNING...AND INT THE CANADIAN MARITIME PROVINCES THROUGH MONDAY NIGHT. HIGH PRESSURE BUILDS IN FROM THE WEST ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... QUITE A BIT GOING ON IN THE NEAR TERM. FIRST...ALL PRECIPITATION IS NOW IN THE FORM OF EITHER RAIN (LONG ISLAND/COASTAL CT AND METRO NYC) OR FREEZING RAIN ELSEWHERE...AS TEMPERATURES ALOFT ONLY SUPPORT LIQUID PRECIPITATION FALLING INTO THE LOWER BOUNDARY LAYER. ACROSS INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND WESTERN PASSAIC COUNTY...SUFFICIENT COLD AIR IS WEDGE IN PLACE AGAINST LOCALLY HIGHER ELEVATIONS...THAT ADDITIONAL SIGNIFICANT ICING (AN ADDITIONAL HALF TO THREE QUARTERS OF AN INCH) IS LIKELY BEFORE TEMPERATURES RISE ABOVE FREEZING TOWARDS THE END OF RUSH HOUR. AS A RESULT THE WINTER STORM WARNING HAS BEEN EXPANDED TO INCLUDE PUTNAM COUNTY. WAS A BORDER LINE CASE AS TO WHETHER TO INCLUDE NORTHERN FAIRFIELD COUNTY OR NOT...IT APPEARS HOWEVER THAT THE TRAJECTORY OF THE HEAVIEST PRECIPITATION THIS MORNING WILL ONLY CLIP THE NORTHERN TIP OF THE COUNTY...SO WILL END UP WITH A WIDE RANGE OF ICE COVERAGE...RANGING FROM A TENTH OF AN INCH JUST N OF THE I-95 CORRIDOR TO UPWARDS OF 3/4 OF AN INCH IN THE FAR NORTHERN TIP...SINCE LESS THAN HALF OF THE NORTHERN FAIRFIELD COUNTY ZONE SHOULD RECEIVE AT LEAST .5 INCHES OF ICE (THE REQUIREMENT FOR A WARNING)...HAVE LEFT AS AN ADVISORY. FOR ADVISORY AREA...HAVE EXTENDED TO 12Z. WOULD NOT BE SURPRISED IF SOME PORTIONS OF THE ADVISORY AREA ENDS UP GETTING EXTENDED AN HOUR OR SO...AS NOT COMPLETELY CONFIDENT TEMPERATURES WARM UP AS FAST AS WHAT IS FORECASTED. TEMPERATURES THIS MORNING BASED ON A BLEND OF RUC 2M TEMPERATURES (WHICH HAVE BEEN SUPERIOR SO FAR IN THESE DAMMING SITUATIONS) AND LAV NUMBERS (WHICH ALSO HAVE FAIRED FAIRLY WELL IN THESE SCENARIOS). (MORE ON TEMPERATURES LATER) NEXT ISSUE IS FLOODING POTENTIAL. HAVE EXPANDED FLASH FLOOD WATCH TO INCLUDE ORANGE AND WESTERN PASSAIC COUNTIES. GFS HAD RIGHT IDEA OF HEAVIER SLUG OF PRECIPITATION GOING OVER THOSE LOCATIONS...AND ON INTO INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND CLIPPING FAR NW CT ZONES...AS EVIDENCE BY REGIONAL RADAR...SO WITH POTENTIAL FOR SIGNIFICANT RAINFALL ON TOP OF A HALF AN INCH TO INCH OF ICE (HELPING TO MAXIMIZE RUNOFF)...HAVE A FLOOD THREAT THERE AS WELL. WHILE RAINFALL WILL BE HEAVY EVERYWHERE BY THIS AFTERNOON...HEAVIEST PRECIPITATION SHOULD BE IN A BAND FROM AROUND NYC NE INTO NE CT IN RESPONSE TO BEING IN RIGHT ENTRANCE REGION OF 160 KT JET...VERY STRONG ISENTROPIC LIFT...AND STRONG LOW LEVEL FRONTOGENETIC FORCING (POSSIBLY CREATING BANDING TO LOCALLY ENHANCE PRECIPITATION). REFER TO HYDROLOGY SECTION FOR DETAILS ON RAINFALL AMOUNTS. AS FOR TEMPERATURES...ALL DEPENDANT ON HOW FAR WARM FRONT MAKES IT. WARM FRONT CURRENTLY BETWEEN BUOYS (44025 AND 44017) AND LONG ISLAND. SHOULD MAKE IT THROUGH AT LEAST EASTERN LONG ISLAND AND SE CT...AND POSSIBLY INTO NYC. NOT REAL CONFIDENT IN IT MAKING IT THROUGH MUCH ELSE...ESPECIALLY WITH LOW PRESSURE CONSOLIDATING TO THE S BY EARLY AFTERNOON. HIGHS BASED ON BLEND OF MAV/FWC/MET BLEND...WHICH WAS USED TO TAMPER WHAT LOOKED TO BE SLIGHTLY TO MUCH WARMING OVER SE AREAS FROM RUC 2M TEMPS AND LAV NUMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... GFS IS OUTLIER WITH ITS DEVELOPMENT OF A STRONG LOW TRACKING JUST TO OUR SOUTHEAST TONIGHT...LEANED TOWARDS WEAKER MORE PROGRESSIVE SOLUTION SUPPORTED BY CMC REGIONAL/NAM/SREF/ECMWF/UKMET. MAIN RESULT WAS TO SIGNIFICANTLY REDUCE POPS OVER MOST OF THE CWA TONIGHT...IF CMC REGIONAL IS RIGHT COULD END UP DRY TONIGHT. BEST CHANCE FOR PRECIPITATION IS OVER SE AREAS...WITH ONLY SLIGHT CHANCE NW. DID KEEP UP FLASH FLOOD WATCH OVERNIGHT...DUE TO RESIDUAL EFFECTS AND TO TRY TO AVOID ANY ISSUES IN CASE GFS CEASES TO BE AN OUTLIER (AM SLIGHTLY NERVOUS BECAUSE GFS HAS BEEN FORECASTING THIS IN ALL RUNS SINCE 00Z LAST NIGHT). THURSDAY AND THURSDAY NIGHT SHOULD BE DRY WITH A RIDGE BUILDING IN ALOFT. TEMPERATURES WILL BE NEAR NORMAL AS WELL. DIFFERENCE IN NAM AND GFS IN TIMING OF NEXT COLD FRONT THAT SHOULD CROSS THE REGION BEGINNING LATE ON FRIDAY. WITH SUPPORT FROM SREF AND UKMET LEANED TOWARDS FASTER GFS TIMING AND A WEAKER FRONT AS WELL. ONE CONSEQUENCE OF THE WEAKER FRONT...IS THAT THE FORCING IS WEAKER...SO HAVE SLIGHTLY LOWER POPS ON FRIDAY AS A RESULT. SHOULD BE A DECENT WARM PUSH AHEAD OF THE FRONT...WITH HIGHS FRIDAY AROUND 10 DEGREES ABOVE NORMAL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE NEXT COLD FRONT WILL PUSH THROUGH THE AREA BY AROUND MIDNIGHT FRIDAY NIGHT. WITH THE BOUNDARY SO WARM INITIAL HAVE A CHANCE OF RAIN/SNOW SHOWERS N CHANCE OF RAIN SHOWERS S IN THE EVENING...THEN WITH SOME EVIDENCE THAT THERE WILL BE POST FRONTAL PRECIPITATION HAVE A CHANCE OF SNOW SHOWERS AT MOST LOCATIONS AFTER MIDNIGHT WITH THE COLDER AIR WORKING IN BEHIND THE FRONT. PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT DUE TO LIMITED MOISTURE AND THE PROGRESSIVE NATURE OF THE SYSTEM. A MORE SIGNIFICANT COASTAL STORM IS EXPECTED TO IMPACT THE AREA LATE SUNDAY THROUGH EARLY TUESDAY. TRACK REMAINS UNCERTAIN...BUT AT THIS POINT WE ARE EXPECTING A MIX OF RAIN AND SNOW ACROSS MUCH OF THE AREA. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... IFR CIGS/VSBYS WILL BE DROPPING TO LIFR TOWARDS DAYBREAK AND WILL REMAIN LIFR (POSSIBLY VLIFR) THROUGH ABOUT 22Z THIS EVENING. FZRA ACROSS KNYC TO KISP TERMINALS WILL BE CHANGING TO PLAIN RAIN OVER THE NEXT HOUR OR SO...WHILE FZRA FURTHER INLAND WILL HOLD OFF UNTIL ABOUT 08-09Z. SN AT KSWF WILL BE MIXING WITH FZRA AND PL THROUGH 08Z...THEN A PROLONGED PERIOD OF FZRA WILL BE EXPECTED THROUGH THIS MORNING. RAIN MAY BECOME HEAVY AT TIMES...RESULTING IN THE LOWERED CONDITIONS. SE WINDS AT 5-10 KT WILL BE INCREASING TO 10-15 KT (15-20 KT AT KNYC TERMINALS) TONIGHT. 60+ 2K FT LLJ KT WILL MOVE INTO THE SOUTHERN PORTION OF TH REGION THIS MORNING...RESULTING IN LLWS ISSUES. WILL EXPECT 50-60 KT WINDS AT 2K FT STARTING AT MANY TERMINALS TOWARDS DAYBREAK... INCREASING TO 60-70 KT WINDS AT 2K FT BETWEEN 10-12Z. LLWS ISSUE DIMINISH AS LOW PRES DEPARTS. CIGS/VSBYS IMPROVE TO MVFR IN THE LATE AFTERNOON/EARLY EVENING...BUT WILL KEEP THE MENTION FOR SOME SHOWERS AS UPPER TROUGH SWINGS THROUGH THE REGION. COLD FRONT SWINGS THROUGH THE REGION BETWEEN 22-02Z. WINDS TURN NW BEHIND THE FRONT AND WILL BE INCREASING TO 10-15 KT WITH GUSTS TO 20 KT DEVELOPING IN THE EVENING. KEPT THE MENTION OF MVFR VSBY DUE TO BR FOR THE EVENING...FIGURING THE COMBINATION OF CAA OVER A SATURATED GROUND WOULD PRODUCE BR. WINDS MAY BE STRONG ENOUGH TO KEEP BR FROM FORMING AND WOULD KEEP IT FROM LASTING TOO MUCH PAST THE END OF THE TAF PERIOD. OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... VFR CIGS/VSBYS THEN IN PLACE LATE TONIGHT THROUGH FRI. ANOTHER COLD FRONT WILL MOVE ACROSS THE AREA FRI NIGHT/EARLY SAT. HIGH PRES RETURNS FOR SUN. && .MARINE... SCA CONDITIONS WERE BEING OBSERVED ACROSS ALL WATERS THIS MORNING WITH GUSTS TO 25 KT AND OCEAN BUOYS 44025 AND 44017 REPORTING SEAS OF 7 AND 5 FT...RESPECTIVELY. SEAS OF 3 FT WERE BEING REPORTED ACROSS LONG ISLAND SOUND. SFC WARM FRONT OVER CENTRAL NJ AT 09Z WILL MOVE ACROSS THE WATERS BETWEEN 10Z AND 12Z. WINDS WILL VEER AROUND FROM THE SE TO SW DURING THIS TIME. FOR A BRIEF TIME...WINDS WILL DROP BELOW SCA THIS AFTERNOON AS THE PRESSURE TROUGH ASSOCIATED WITH THE COLD FRONT MOVES ACROSS THE WATERS...FROM 18Z TO 22Z. COLD ADVECTION THIS EVENING AND A STRENGTHENING NW FLOW WILL BRING WINDS BACK UP ACROSS THE COASTAL WATERS...WITH A MARGINAL GALE ON THE OCEAN AND SCA ELSEWHERE. THESE CONDITIONS WILL PREVAIL UNTIL AROUND 18Z THU. THE 00Z GFS CONTINUES TO SUPPORT A SECOND WAVE DEVELOPING ALONG THE MID ATLANTIC COAST THIS EVENING...THEN TAKING A TRACK SEVERAL HUNDRED MILES TO THE SE OF MONTAUK POINT BY 12Z THU. THE MAGNITUDE OF THIS LOW IS AN OUTLIER AMONGST THE GLOBAL MODEL SUITE AND THE GFS ENSEMBLE. THE GREATEST LIKELIHOOD OF SEEING GALE FORCE WINDS ON THE OCEAN WATERS LOOKS TO BE FROM 06Z TO 18Z THU. HI PRES BUILDS ACROSS THE WATERS THU AFT AND NIGHT...THEN EAST OF THE WATERS BY 12Z FRI. ANOTHER FRONTAL SYSTEM WILL IMPACT THE AREA FRI EVE WITH STRONG COLD ADVECTION TO FOLLOW INTO SAT MORNING WITH SCA CONDITIONS LIKELY TO RETURN ON ALL WATERS. HI PRES BUILDS BACK IN SAT AFT AND NIGHT FOLLOWED BY A STRENGTHENING RETURN FLOW ON SUN. && .HYDROLOGY... EVEN WITH MINIMAL QPF NO EXPECTED TONIGHT...STILL HAVE THE POTENTIAL FOR 1.5 (NW) TO 2.5 INCHES (BAND FROM NEAR NYC TO NE CT) OF RAINFALL TODAY WITH LOCALLY HIGHER AMOUNTS. THIS COMBINED WITH SNOW MELT OR FALLING ON TOP OF ICE ENCRUSTED SNOW...PROMOTING MORE RUNOFF THAN USUAL...PRESENT THE POTENTIAL FOR FLASH FLOODING ACROSS THE ENTIRE CWA. FLASHY RIVERS COULD STILL BE IN FLOOD THIS EVENING...PLUS RESIDUAL FLOODING IN URBAN AREAS WARRANT CONTINUING FLOOD WATCH INTO TONIGHT...EVEN THOUGH PRECIPITATION POTENTIAL IS GREATLY REDUCED. IF BANDING DOES DEVELOP...COULD END UP WITH VERY HEAVY RAINFALL RATES...OF AN INCH OR MORE AN HOUR...THIS WILL ADD TO ENHANCE POTENTIAL FOR FLASH FLOODING. AFTER THIS...NEXT POTENTIAL FOR SIGNIFICANT PRECIP IS WITH COASTAL STORM SYSTEM FOR EARLY NEXT WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH THURSDAY MORNING FOR CTZ005>012. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR CTZ005>008. NY...FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH THURSDAY MORNING FOR NYZ067>081. WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR NYZ067- 068. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NYZ069- 070. NJ...FLOOD WATCH FROM 7 AM EST THIS MORNING THROUGH THURSDAY MORNING FOR NJZ002>006-011. WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR NJZ002. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR NJZ003- 004. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ330-335- 338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ350- 353-355. GALE WARNING FROM 6 PM THIS EVENING TO 1 PM EST THURSDAY FOR ANZ350-353-355. && $$ SYNOPSIS...PFM NEAR TERM...PFM SHORT TERM...PFM LONG TERM...PFM/MET AVIATION...MPS MARINE...DW HYDROLOGY...PFM ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 424 AM EST WED FEB 13 2008 .SYNOPSIS... A COMPLEX LOW PRESSURE SYSTEM WILL MOVE OFF THE MID-ATLANTIC COAST TONIGHT...BRINGING A COLD FRONT THROUGH THE AREA. HIGH PRESSURE WILL BUILD IN FOR THURSDAY AND FRIDAY BEFORE ANOTHER STORM SYSTEM AFFECTS THE AREA OVER THE UPCOMING WEEKEND. HIGH PRESSURE WILL RETURN FOR THE FIRST HALF OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FIRST BATCH OF WIDESPREAD RAINFALL HAS SHIFTED NE OF THE FORECAST AREA AS STRONG UPPER DIVERGENCE WITH THE UPPER JET AS WELL AS A WEAK H500 SHORTWAVE MOVE AWAY FROM THE AREA. LOW-LEVEL MOISTURE WILL REMAIN ABUNDANT TODAY...THUS EVEN WEAK VERTICAL VELOCITIES WILL FORM SOME LIGHT TO MODERATE RAIN SHOWERS. A LULL IN PRECIP SHOULD OCCUR OVER MOST INLAND AREAS FOR THE MORNING HOURS...THEN ANOTHER BRIEF BATCH OF SHOWERS COULD MOVE THROUGH DURING THE AFTERNOON AS ANOTHER WEAK SHORTWAVE MOVES THROUGH THE AREA AHEAD OF THE PRIMARY VORT. HAVE POPS TAPERING BACK PRETTY RAPIDLY THIS MORNING WITH MAINLY CHANCE TO SLIGHT CHANCE POPS. ABUNDANT CLOUD COVER AND A RAIN-COOLED BOUNDARY LAYER SHOULD ELIMINATE ANY THUNDERSTORM CHANCES TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... CLOUDS WILL CLEAR OUT RAPIDLY LATE IN THE AFTERNOON INTO THE EVENING HOURS WITH STRONG NEGATIVE VORTICITY ADVECTION AND LOW- LEVEL COLD AIR ADVECTION. A SOLID ADVECTION FREEZE IS EXPECTED TO OCCUR MOST AREAS AWAY FROM THE IMMEDIATE COAST. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HIGH PRESSURE WILL BUILD OVER THE REGION ON THURSDAY...BRINGING WITH IT A VERY DRY AIRMASS. THE HIGH WILL SHIFT OFFSHORE FRIDAY...ALLOWING A RETURN FLOW TO DEVELOP. A WEAK FRONTAL BOUNDARY SHOULD DROP ACROSS THE AREA ON SATURDAY THEN STALL SOUTH AND EAST OF THE AREA SATURDAY NIGHT. DUE TO A LACK OF ANY SIGNIFICANT FORCING...MEDIUM RANGE GUIDANCE HAS TRENDED DRIER FOR SATURDAY AND WILL FOLLOW SUIT WITH ONLY A SLIGHT CHANCE OF SHOWERS ACROSS THE AREA. ISENTROPIC LIFT WILL DEVELOP OVER THE BOUNDARY SATURDAY NIGHT AND WILL FORECAST A CHANCE OF SHOWERS. THE BOUNDARY WILL LIFT NORTH AS A WARM FRONT ON SUNDAY IN RESPONSE TO LOW PRESSURE TRACKING NORTHEAST ACROSS THE GULF COAST STATES. WILL CONTINUE TO FORECAST A CHANCE OF SHOWERS AS A MOISTURE RICH SOUTHERLY FLOW DEVELOPS ACROSS THE AREA. A POTENT COLD FRONT WILL SWING THROUGH THE AREA SUNDAY NIGHT INTO EARLY MONDAY. ALONG WITH THE CONTINUED CHANCE OF SHOWERS...WILL KEEP MENTION OF A SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST DURING THIS TIME PERIOD. LARGE SCALE ASCENT AND WIND FIELDS LOOK RATHER IMPRESSIVE IN ASSOCIATION WITH THIS FRONTAL BOUNDARY...BUT AS USUAL FOR THIS TIME OF YEAR INSTABILITY APPEARS TO BE LACKING. HIGH PRESSURE WILL RETURN FOR EARLY NEXT WEEK WITH DRY CONDITIONS EXPECTED. AS FOR TEMPERATURES IN THE LONG TERM...SLIGHTLY BELOW NORMAL TEMPERATURES ARE EXPECTED THURSDAY. TEMPERATURES SHOULD THEN RISE ABOVE NORMAL FRIDAY ONCE THE RETURN FLOW DEVELOPS...AND REMAIN ABOVE NORMAL THROUGH THE WEEKEND. COOLER WEATHER SHOULD THEN PREVAIL EARLY NEXT WEEK FOLLOWING THE PASSAGE OF THE COLD FRONT. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... MAIN BATCH OF PRECIP ASSOCIATED WITH STRONG UPPER DIVERGENCE AND A WEAK SHORTWAVE MOVING THROUGH IS PULLING OFF TO THE E OF CHS TERMINAL EARLY THIS MORNING. ONLY LIGHT RAIN IS FALLING BEHIND THIS AREA...INCLUDING THE SAV AIRPORT. BEHIND THIS AREA OF ACTIVITY IS A LULL IN PRECIP BUT EXTENSIVE IFR CEILINGS. THUS WE EXPECT PRECIP TO TAPER OFF DURING THE NEXT FEW HOURS BUT CEILINGS LOWERING TO IFR AT BOTH SITES. A DYING PRE-FRONTAL BAND OF PRECIP MOVING ACROSS WESTERN GA MAY AFFECT EITHER TERM AFTER DAYBREAK BUT DO NOT THINK COVERAGE WILL BE VERY HIGH AT THAT POINT. SLOWLY IMPROVING CONDITIONS LATER TODAY AS WINDS VEER TO W AND DRIER AIR ADVECTS INTO THE AREA. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL...ALTHOUGH PERIODS OF MVFR CONDITIONS OR LOWER ARE POSSIBLE IN SHOWERS OVER THE WEEKEND. && .MARINE... CONDITIONS OVER THE WATERS HAVE GENERALLY BEEN QUITE CALM FOR THE LAST SEVERAL HOURS. RUC-13 925 MB WIND SPEED PROG HAS BEEN DOING VERY WELL AT SHOWING AREAS OF GREATEST GUST POTENTIAL. THE NW LOBE OF A 50 KT JET IS JUST NOW PUSHING OFF TO THE E ACROSS OFFSHORE SC WATERS. WINDS AT BUOY 41004 HAVE HAD...BY FAR...THE HIGHEST WIND SPEEDS THIS MORNING WITH 15-20 KT THE GENERAL TREND. SEAS HAVE REACHED A WHOPPING 17 FEET...INDICATING THE WINDS JUST SE OF THE BUOY ARE SOLIDLY AT GALE FORCE WHERE THE WATERS ARE MUCH WARMER AND THE LOW-LEVEL JET IS STRONGEST. FOLLOWING THE RUC/S TREND ...LOW-LEVEL WINDS DROP OFF DRAMATICALLY THROUGH LATE MORNING. ACROSS THE NEARSHORE WATERS...WE REALLY DO NOT ANTICIPATE SUSTAINED WINDS GETTING MUCH ABOVE 20 KT UNTIL LATE IN THE AFTERNOON WHEN THE COLD FRONT MOVES THROUGH AND COLD ADVECTION IMPROVES MIXING PROFILES. SOME GUSTS TO 25 KT ARE POSSIBLE IN THE HARBOR TODAY DUE TO BETTER MIXING ALONG THE LAND-SEA INTERFACE. PLAN TO CARRY SMALL CRAFT ADVISORIES ALL WATERS TODAY...MAINLY FOR SEAS. DELAYED ONSET OF GALE WARNING FOR OFFSHORE GA WATERS UNTIL LATE THIS AFTERNOON SINCE LOW-LEVEL JETTING WILL NOT SUPPORT GALE FORCE WINDS UNTIL THEN. WILL HEADLINE SMALL CRAFT ADVISORY FOR OFFSHORE GA WATERS UNTIL GALE WARNING INITIATES. COLD ADVECTION REALLY CRANKS UP IN EARNEST BETWEEN 00 AND 03Z THIS EVENING WHILE 925 MB WINDS ON THE NAM-12 ARE IN THE 25-30 KT RANGE. A SLIGHT INCREASE IN WINDS TOWARD 06Z IS EXPECTED. ANTICIPATING A LOW-BIAS IN MODEL WINDS WITH STRONG POST-FROPA COLD ADVECTION...WILL KEEP GALE WARNING FOR OFFSHORE GA WATERS FOR TONIGHT. GALE FORCE WIND CRITERION IS EXPECTED TO MAINLY BE MET WITH FREQUENT GUSTS. CONDITIONS WILL IMPROVE PRETTY QUICKLY ACROSS ALL OF THE WATERS LATE TONIGHT WHEN LOW-LEVEL JET PULLS AWAY FROM THE WATERS AND COLD ADVECTION DIMINISHES. BENIGN CONDITIONS ARE EXPECTED OVER THE COASTAL WATERS THURSDAY AND FRIDAY AS HIGH PRESSURE DOMINATES. A BACK DOOR COLD FRONT WILL DROP ACROSS THE WATERS SATURDAY AND STALL JUST TO THE SOUTH AND EAST SATURDAY NIGHT. THIS WILL CAUSE A STRENGTHENING NORTHEAST FLOW TO DEVELOP...AND WINDS COULD REACH 15-20 KT AT TIMES OVER PORTIONS OF THE COASTAL WATERS WITH ANY PINCHING OF THE GRADIENT. THE BOUNDARY WILL LIFT BACK TO THE NORTH AS A WARM FRONT ON SUNDAY AS A COLD FRONT APPROACHES FROM THE WEST. MODELS ARE SHOWING VERY STRONG LOW LEVEL WINDS IN PLACE AHEAD OF THE FRONT...AND SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED OVER MOST OF THE WATERS BEGINNING LATE SUNDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR AMZ330- 352-354. SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ350. SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR AMZ374. GALE WARNING FROM 5 PM THIS AFTERNOON TO 5 AM EST THURSDAY FOR AMZ374. && $$ JRL/JAQ ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 157 AM EST WED FEB 13 2008 .SYNOPSIS... A COMPLEX LOW PRESSURE SYSTEM WILL MOVE NORTHEAST THROUGH GA AND SC TONIGHT THEN OFF THE MID-ATLANTIC COAST ON WED PULLING A COLD FRONT THROUGH THE AREA. HIGH PRESSURE WILL BUILD OVER THE AREA INTO FRIDAY. A COLD FRONT WILL THEN ADVANCE INTO THE SOUTHEAST AND WILL STALL OVER THE REGION FRIDAY NIGHT INTO SATURDAY...LIFTING NORTH AS A WARM FRONT AS LOW PRESSURE TRACKS NORTHEAST FROM THE GULF OF MEXICO FOR THE LATTER HALF OF THE WEEKEND. THE LOW WILL THEN DRIVE A COLD FRONT THROUGH THE SOUTHEAST AND HIGH PRESSURE WILL RETURN FOR THE FIRST HALF OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... ISSUING AN UPDATE TO FORECAST TO REMOVE THUNDER FROM MOST AREAS EXCEPT FAR EASTERN PORTIONS THROUGH DAYBREAK. INSTABILITY IS VERY MARGINAL DUE TO RAIN COOLED BOUNDARY LAYER AND UPPER DIVERGENCE AHEAD OF THE JET STREAM IS NOW PUSHING OFF TO THE E OF THE AREA. ALSO HAVE LOWERED THE WIND ADVISORY FOR COASTAL CHARLESTON AND COLLETON. LATEST SFC OBS ARE LESS THAN 15 KT ALONG THE COAST...EVEN BEACH LOCATIONS SUCH AS ISLE OF PALMS AND SULLIVANS ISLAND. RUC-13 SHOWS THE 35 KT 925 MB JET IS NOW JUST BRUSHING FAR EASTERN PORTIONS OF THE AREA. WITH UPPER WINDS DECREASING AND POOR MIXING PROFILES...DO NOT EXPECT CRITERIA WINDS TO BE MET THROUGH THE REMAINDER OF THE NIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... SFC LOW PRES AREA OVER THE GULF STATES WILL BE THRUST INTO NC BY DAYBREAK WED WHILE THE SHARP UPR TROF CROSSES THE MISS RIVER AND THE SFC CDFNT IS OVER CENTRAL SC AND ERN GA. THE BULK OF THE PRECIP WILL BE OFFSHORE...THUS PRECIP CHCS DECREASE MAINLY BECAUSE OF LACK OF COVERAGE AS CONFIDENCE IS FAIRLY HIGH THAT SCAT SHWRS WILL BE LINGERING IN THE MRNG HOURS. AS THE LOW PULLS AWAY DURING THE DAY TMRW...WRAP-AROUND MOISTURE BEHIND THE SFC LOW AND JUST AHEAD OF THE NEGATIVELY-TILTING TROF MAY BRING A BRIEF BOUT OF SHWRS INTO THE MID-LATE AFTN HOURS FOR MAINLY NRN SECTIONS OF THE CWFA. OTHERWISE...BY LATE AFTN SKIES WILL CLEAR OUT RATHER QUICKLY FROM S TO N AS THE CDFNT MOVES OFFSHORE. MILD TEMPS IN THE MRNG WILL NOT RISE TOO MUCH BY TMRW AFTN...PRODUCING HIGHS ONLY REACHING THE UPR 50S WELL INLAND TO MID 60S CLOSER TO THE COAST. SKIES WILL CONTINUE CLEARING OUT TMRW EVE AND TMRW NIGHT AS HIGH PRES APPROACHES FROM THE W. CAA WILL NOT BE ALL THAT IMPRESSIVE WITH THIS HIGH PRES AIRMASS BEHIND THE COMPLEX LOW PRES SYSTEM... BUT IT WILL BE ENOUGH TO DROP MIN TEMPS WED NIGHT TO THE UPR 20S WELL INLAND TO THE MID 30S CLOSER TO THE COAST. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT EARLY IN THE EXTENDED PERIOD THIS AFTERNOON...WITH SOLUTIONS THEN DIVERGING OVER THE WEEKEND AND INTO EARLY NEXT WEEK. HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE ACROSS THE AREA THURSDAY THROUGH FRIDAY NIGHT. A WEAK FRONTAL BOUNDARY IS THEN EXPECTED TO PUSH SOUTHWARD THROUGH THE REGION SATURDAY AND STALL JUST SOUTH OF THE CWA SATURDAY NIGHT. THIS FRONTAL BOUNDARY IS THEN EXPECTED TO LIFT BACK NORTHWARD AS A WARM FRONT SUNDAY...WITH A COLD FRONT TO FOLLOW SUIT ON MONDAY. HIGH PRESSURE IS THEN EXPECTED TO BUILD BACK INTO THE REGION MONDAY NIGHT AND TUESDAY. AS FOR FORECAST DETAILS...WILL KEEP THE FORECAST RAIN FREE THURSDAY THROUGH FRIDAY NIGHT WITH HIGH PRESSURE IN PLACE. THE GFS IS MUCH MORE BULLISH WITH QPF AMOUNTS OVER THE WEEKEND THAN THE ECMWF/CANADIAN/NOGAPS AND GIVEN LACK OF LARGE SCALE ASCENT IT APPEARS THAT THE GFS IS OVERDONE. HAVE BACKED OFF POPS ACCORDINGLY...AND HAVE CARRIED LOW CHANCE POPS BOTH SATURDAY AND SATURDAY NIGHT. TIMING ISSUES BEGIN TO CREEP INTO THE PICTURE SUNDAY THROUGH MONDAY...WITH THE GFS AND CANADIAN ADVERTISING THE COLD FRONTAL PASSAGE SUNDAY NIGHT...WITH THE ECMWF/CANADIAN/NOGAPS SUGGESTING A FRONTAL PASSAGE ON MONDAY. THE MAJORITY OF THE 12Z GFS ENSEMBLE MEMBERS FAVORED THE SLOWER FRONTAL PROGRESSION AND WILL FAVOR THIS SLOWER SOLUTION WITH THE AFTERNOON PACKAGE. GIVEN UNCERTAINTY THIS FAR OUT IN THE FORECAST...WON/T FOCUS TOO MUCH ON THE TIMING DETAILS AT THIS POINT AND WILL CARRY CHANCE POPS SUNDAY THROUGH MONDAY...WITH RAIN FREE WEATHER TO FOLLOW FOR MONDAY NIGHT AND TUESDAY. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... MAIN BATCH OF PRECIP ASSOCIATED WITH STRONG UPPER DIVERGENCE AND A WEAK SHORTWAVE MOVING THROUGH IS PULLING OFF TO THE E OF CHS TERMINAL EARLY THIS MORNING. ONLY LIGHT RAIN IS FALLING BEHIND THIS AREA...INCLUDING THE SAV AIRPORT. BEHIND THIS AREA OF ACTIVITY IS A LULL IN PRECIP BUT EXTENSIVE IFR CEILINGS. THUS WE EXPECT PRECIP TO TAPER OFF DURING THE NEXT FEW HOURS BUT CEILINGS LOWERING TO IFR AT BOTH SITES. A DYING PRE-FRONTAL BAND OF PRECIP MOVING ACROSS WESTERN GA MAY AFFECT EITHER TERM AFTER DAYBREAK BUT DO NOT THINK COVERAGE WILL BE VERY HIGH AT THAT POINT. SLOWLY IMPROVING CONDITIONS LATER TODAY AS WINDS VEER TO W AND DRIER AIR ADVECTS INTO THE AREA. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL WEDNESDAY NIGHT THROUGH FRIDAY. PERIODS OF MVFR OR LOWER CONDITIONS ARE POSSIBLE IN PRECIPITATION FRIDAY NIGHT THROUGH NEXT WEEKEND. && .MARINE... ISSUING QUICK UPDATE TO REPLACE GALES FOR NEARSHORE WATERS AND HARBOR WITH SMALL CRAFT ADVISORIES. LATEST FEW HOURS OF CONDITIONS OVER THESE AREAS SHOW WINDS AROUND 15 KT WITH A FEW HIGHER GUSTS. THE ONLY REAL STRONG WINDS ARE OVER BUOY 41004 WHERE THE RUC-13 DEPICTS A 40-45 KT 925 MB JET. THE WATER IS ALSO QUITE A BIT WARMER BEYOND 20 NM FROM SHORE. AS THE LOW-LEVEL JET PUSHES E OF THE WATERS DURING THE NEXT FEW HOURS...CHANCE FOR GALE FORCE WINDS IN NEARSHORE WATERS RAPIDLY DIMINISHES. ONCE THE FRONT MOVES OFFSHORE...SEAS WILL DROP OFF RATHER STEADILY LATE TMRW INTO TMRW EVE THEN WIND SPEEDS WILL FOLLOW TMRW NIGHT INTO THU MRNG. FOLLOWING THE FRONT WILL BE AN EXTENSIVE AREA OF HIGH PRESSURE...THUS BRINGING ALL MARINE ZONES BELOW HEADLINE CRITERIA BY DAYBREAK ON THU. EXTENDED MARINE...HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE OVER THE WATERS THURSDAY THROUGH FRIDAY NIGHT. A WEAK FRONTAL BOUNDARY WILL PUSH SOUTHWARD THROUGH THE WATERS SATURDAY...THEN STALL JUST SOUTH OF THE REGION SATURDAY NIGHT. THIS FRONTAL BOUNDARY WILL THEN LIFT BACK NORTHWARD THROUGH THE WATERS ON SUNDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT THRESHOLDS THURSDAY THROUGH SATURDAY NIGHT. SOUTHERLY WINDS WILL INCREASE QUITE A BIT LATE SUNDAY AS THE WARM FRONT PUSHES NORTHWARD THROUGH THE AREA...AND SMALL CRAFT ADVISORIES MAY EVENTUALLY BE NEEDED FOR WINDS/SEAS OR A COMBINATION OF THE TWO ACROSS PORTIONS OF THE WATERS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR AMZ330- 352-354. SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ350. GALE WARNING UNTIL 11 PM EST THIS EVENING FOR AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 201 AM MST WED FEB 13 2008 .DISCUSSION...00Z H5 ANALYSIS INDICATING VERY LARGE HEIGHT FALLS ACROSS THE PAC NW WHILE WATER VAPOR/RUC ANALYSIS SHOWING ROBUST MID/UPPER TROUGH DIGGING INTO THE PAC NW/NORTHERN INTERMOUNTAIN REGION EARLY THIS MORNING. AHEAD OF THIS TROUGH...SHORTWAVE RIDGING WILL BUILD OVER THE CENTRAL HIGH PLAINS WITH PRESSURE FALLS OVER NORTHEAST COLORADO LATE IN THE PERIOD. AS THE PRESSURE GRADIENT TIGHTENS...SOUTHERLY SFC WINDS WILL INCREASE TO 20-30 MPH ACROSS THE AREA TODAY. A SOUTHWEST COMPONENT WEIGHTED ACROSS THE WESTERN ZONES MAY LEAD TO A FEW LOCATIONS REACHING 60 DEGREES. ANOTHER BLAST OF ARCTIC AIR IS EXPECTED TO BUILD INTO THE NORTHERN PLAINS ON THURSDAY...HOWEVER THE H85 THERMAL TROUGH WILL REMAIN NORTH AND EAST OF THE CENTRAL HIGH PLAINS WITH MODIFIED ARCTIC AIR EXPECTED AT THIS TIME. LITTLE IF ANY INSOLATION IS EXPECTED WITH STRONG LOW LEVEL CAA IN POST-FRONTAL REGIME. A PERIOD OF POST-FRONTAL SNOW STILL APPEARS ON TRACK WEIGHTED ACROSS THE WESTERN ZONES AFTER 09-11Z AS H7 BAROCLINIC ZONE MOVES THROUGH THE AREA AND TRANSIENT AREA OF MID LVL FRONTOGENESIS IS JUXTAPOSED WITH STRONGER LARGE SCALE FORCING FOR ASCENT EVIDENT IN THE H5-H3 DIV Q FIELDS. CROSS-SECTIONS OF GEO MOMENTUM/EQUIV POT TEMP TAKEN NORMAL TO H85-H3 THICKNESS SUGGEST THE BEST RESPONSE TO THE FORCING WILL BE ACROSS EASTERN COLORADO GENERALLY WEST OF THE FORECAST AREA AND WILL KEEP THE HIGHEST ACCUMULATIONS (1-2 INCHES) WEIGHTED OVER THE THE FAR WESTERN ZONES. A FEW FLURRIES MAY LINGER INTO THE EVENING HOURS ON THURSDAY BEFORE SUBSIDENCE BUILDS OVER THE REGION WITH A COLD NIGHT EXPECTED. HIGHS ON FRIDAY WILL BE CHALLENGING AS THE ARCTIC COLD FRONT MAY BISECT THE AREA LEADING TO LARGE TEMPERATURE DIFFERENCES. WILL GENERALLY FOLLOW THE PREVIOUS FORECAST WITH HIGHS RANGING FROM AROUND 40 NORTHWEST TO AROUND 30 EAST. DAYS 4 THROUGH 7...NO CHANGES. && .AVIATION...FOR THE 06Z TAF...VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WINDS WILL START TO PICK UP DURING THE DAY ON WEDNESDAY SUBSIDING AFTER SUNSET WEDNESDAY EVENING. SHORTWAVE TROUGH APPROACHES TOWARD THE END OF THE TAF PERIOD BUT CURRENT THINKING WOULD HOLD ANY PRECIP CHANCES AND LOWER CIGS OFF UNTIL AFTER 06Z THURSDAY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ MCGUIRE/FOLTZ ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1210 AM EST WED FEB 13 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAFS .UPDATE (ISSUED AT 1025 PM EST)... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SHORTWAVE HEADING ENE THRU LWR MI WHILE NEXT SHORTWAVE IS DROPPING SE THRU MANITOBA INTO NRN ONTARIO. PATCHY -SN/FLURRIES ASSOCIATED WITH LWR MI SHORTWAVE SHOULD EXIT THE ERN FCST AREA IN THE NEXT COUPLE OF HRS. ATTENTION THEN TURNS TO THE COLD FRONT EXTENDING FROM NRN ONTARIO THRU FAR NW MN...ASSOCIATED WITH UPSTREAM SHORTWAVE. KDLH RADAR AND SFC OBS INDICATED -SN/FLURRIES AHEAD OF FRONT IN NRN MN. THE -SN IS OCCURRING IN A NARROW RIBBON WEAK DEEP LAYER QVECTOR CONVERGENCE AND MOIST ISENTROPIC ASCENT (280K THETA SFC) PER 00Z RUC. AS FORCING AND ISENTROPIC ASCENT SPREAD E OVERNIGHT...850MB TEMPS AROUND -14C WILL BE PLENTY COLD ENOUGH TO SUPPORT LAKE ENHANCEMENT AS THE COLD FRONT CROSSES WRN LAKE SUPERIOR. PER 00Z RUC/NAM...FRONT SHOULD REACH THE KEWEENAW IN THE 10-12Z TIME FRAME. EXPECT A BRIEF BURST OF MDT/HVY SNOW WITH FROPA. CERTAINLY COULD SEE A QUICK 1-3 INCHES OF ACCUMULATION...ESPECIALLY WITH FAVORABLE DENDRITIC SNOW GROWTH TEMPS IN THE LAYER OF ASCENT. CONSIDERED AN ADVY AS LATE NIGHT THRU WED MORNING SNOW ACCUMULATIONS ON THE KEWEENAW MAY APPROACH ADVY LEVELS. HOWEVER...SINCE INVERSION WILL BE CRASHING QUICKLY TO 3.5-4KFT BEHIND FRONT...WILL HOLD OFF AN ADVY FOR NOW. TO THE E...INCREASED POPS TO LIKELY FOR ALGER/LUCE WED AFTN UNDER NW FLOW BEHIND COLD FRONT. && .PREV DISCUSSION (ISSUED AT 416 PM EST)... SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM CA INTO THE NRN ROCKIES/ALBERTA AND A TROUGH FROM CNTRL CANADA INTO THE MS VALLEY. A SHORTWAVE FROM SW WI INTO ERN IA SUPPORTED AN AREA OF LIGHT SNOW FROM ERN WI INTO SRN UPPER MI. AN UPSTREAM SHORTWAVE WAS MOVING SE THROUGH SRN MANITOBA. 700-500 QVECTOR CONV AND 280K ISENTROPIC LIFT ASSOCIATED WITH THIS FEATURE ALSO HAS PRODUCED SOME LIGHT SNOW WITH VSBY INTO THE 1-3SM RANGE AHEAD OF SFC COLD FRONT. SHORT TERM (TONIGHT AND WED)... MAIN FCST CONCERNS ARE LIGHT SNOW CHANCES SE THIS EVENING AND LES INTO NW UPPER MI LATE TONIGHT INTO WED. EXPECT LIGHT SNOW WITH THE WI SHORTWAVE WILL BRUSH THE SE PORTION OF THE CWA LATE THIS AFTERNOON AND EARLY EVENING. RADAR AND UPSTREAM OB TRENDS SUGGEST THAT ANY ACCUMULATIONS SHOULD BE MINIMAL...LESS THAN A HALF INCH. WINDS SHOULD BACK ENOUGH TO THE NE TO REDUCE CHANCES FOR LES OR LAKE ENHANCED SNOW OFF OF LAKE MI. LATE TONIGHT THE SHORTWAVE AND SFC FRONT WILL MOVE INTO WRN LAKE SUPERIOR WITH WINDS VEERING FROM SW TO WNW AROUND 12Z. 850 MB TEMPS TO AROUND -15C BY 12Z SHOULD SUPPORT INCREASING LES POTENTIAL INTO NW UPPER MI. SNOW GROWTH PARAMETERS ARE FAVORABLE BTWN 09Z-15Z WITH THE 2K-8K FT LAYER IN THE -12C TO -17C RANGE. HOWEVER...THE PERIOD OF BEST LOW LEVEL CONV IS RELATIVELY BRIEF AND THE DEEPER MOISTURE MOVES OUT BEFORE THE COLDER AIR ARRIVES. VERY DRY AIR MOVING IN BY MIDDAY ALONG WITH A SHORTER FETCH AS WINDS VEER NW AND INVERSION HEIGHTS FALLING TO AROUND 4K FT...SHOULD DECREASE SNOWFALL RATES/COVERAGE WITH MAINLY SCT -SHSN/FLURRIES BY AFTERNOON. WRLY WINDS JUST BRUSHING THE SHORELINE E OF MUNISING WILL VEER NW IN THE AFTERNOON. AGAIN...BY THAT TIMES...SIGNIFICANT DRY ADVECTION AND LOWERING INVERSION HEIGHTS WILL LIMIT LES POTENTIAL WITH ONLY LIGHT ACCUMULATIONS. LONG TERM (WED NIGHT THRU TUE)... AS POINTED OUT BY HPC...ECMWF IS THE PREFERRED SOLUTION THROUGH THE EXTENDED. THE MID LEVEL LOW OVER NORTHERN ONTARIO WILL MOVE OVER NORTHERN ONTARIO WEDNESDAY NIGHT AS A WEAK SHORTWAVE WRAPPING AROUND THIS LOW SWEEPS INTO THE NORTHERN PLAINS. A SURFACE LOW ASSOCIATED WITH THIS SHORTWAVE WILL DEEPEN OVER THE CENTRAL PLAINS. THE ACCOMPANYING COLD FRONT WILL MOVE SOUTHEAST OVERNIGHT STRETCHING FROM SOUTHEAST ONTARIO THROUGH NORTHERN LOWER MICHIGAN TO THE LOW OVER THE TEXAS PANHANDLE. CONSIDERABLE AMOUNT OF LOW LEVEL MOISTURE WILL MOVE INTO THE AREA AHEAD OF THE LOW. THE STRONGEST ISENTROPIC ASCENT WILL STILL BE OVER WISCONSIN. THE MID LEVEL LOW WILL LIFT INTO SOUTHEAST HUDSON BAY DIRECTING A SHORTWAVE THROUGH THE U.P. ON THURSDAY. THE SURFACE LOW WILL MOVE INTO NORTHERN WISCONSIN. WINDS SHOULD DECREASE OVER THE FORECAST IN THE CLOSE PROXIMITY OF THE LOW. GUIDANCE SHOWING THE DEEPEST MOISTURE WILL BE TO THE SOUTH OF THE FORECAST AREA. DELTA-T`S WILL AROUND -23C. PLAN TO GO WITH A WATCH FOR MOST OF THE SOUTHERN COUNTIES AS THIS WILL BE CLOSEST TO THE DEEPEST MOISTURE FIELD AND THE AREA OF STRONGEST 850-500MB Q-VECTORS CONVERGENCE DURING THE DAY. AFTER THE SURFACE LOW SETTLE INTO LOWER MICHIGAN ON THURSDAY...THE WINDS WILL BECOME MORE NORTHERLY. THE SURFACE RIDGE WILL SWEEP INTO THE UPPER MISSISSIPPI RIVER VALLEY THURSDAY NIGHT. THUS LOOKING FOR LES TO DEVELOP OVER THE WESTERN U.P. AND EAST OF MUNISING AGAIN THURSDAY NIGHT. THE MID LEVEL CLOSED LOW WILL SHIFT INTO WEST CENTRAL QUEBEC AS A WEAK SHORTWAVE RACE ACROSS THE FORECAST AREA. THE SURFACE WINDS WILL BACK WEST ON FRIDAY AS THE RIDGE DESCENDS ON THE UPPER GREAT LAKES. THE DELTA-T`S WILL BE AROUND 20C. WINDS WILL CONTINUE TO BACK TO THE WEST. THUS THE LAKE EFFECT SNOWS WILL END AS THE RIDGE MOVES THROUGH. THE LONGWAVE TROUGH WILL SLIDE INTO NEW ENGLAND FRIDAY NIGHT WHILE SURFACE HIGH MOVES INTO THE OHIO RIVER VALLEY AND THE LOWER GREAT LAKES. WINDS WILL BE LIGHT EARLY AND BECOME OUT OF THE SOUTHWEST LATE. THE WATER-850MB DELTA-T`S WILL BE AROUND 20C OVER EASTERN LAKE SUPERIOR TO AROUND 14C OVER THE WEST. STILL BOTH COOL ENOUGH TO GENERATE SOME LAKE EFFECT SNOW. HOWEVER...WITH THE LIGHT WINDS AND WINDS BACKING SOUTHWEST...THE LES WILL SHIFT OUT OF THE U.P. MEANWHILE...A COLD FRONT WILL DEVELOP OVER SOUTH CENTRAL CANADA AND SWEEP INTO NORTHERN MINNESOTA AND WESTERN ONTARIO ON SATURDAY. WEAK ISENTROPIC ASCENT AHEAD OF THE FRONTAL SYSTEM AND LOW LEVEL MOISTURE DRAWN INTO THE AREA WITH THE SOUTHWEST FLOW WILL GENERATE SOME SNOWS OVER THE AREA. SINCE THE WEST END OF THE FORECAST AREA IS STILL FAR ENOUGH AWAY FROM THE FRONT THE CHANCES WILL STILL BE SLIGHT. THE LOW AND ACCOMPANYING COLD FRONT WILL SWEEP INTO THE U.P. SATURDAY NIGHT AND INTO EASTERN ONTARIO ON SUNDAY. MEANWHILE...A TROUGH DEEPENING OVER SOUTH CENTRAL CANADA WILL MOVE OVER WESTERN ONTARIO AND THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY NIGHT AND THROUGH THE U.P. ON SUNDAY. WINDS WILL SHIFT NORTHWEST FOLLOWING THE FROPA. THE CHANCE OF SNOW WILL SPREAD ACROSS THE FORECAST AREA. COLD AIR WILL STREAM INTO THE AREA SUNDAY NIGHT AND MONDAY. A LOW LEVEL THERMAL TROUGH WILL MOVE INTO WESTERN ONTARIO AND THE 850MB TEMPERATURES DROP TO AROUND -20C OVER THE WESTERN LAKE. THIS SHOULD GENERATE LES...MAINLY OVER AREAS PRONE TO LES WITH A NORTHWEST FLOW. THE LONGWAVE TROUGH WILL REMAIN OVER THE UPPER GREAT LAKES REGION THROUGH TUESDAY...CONTINUING TO PULL COLD AIR INTO THE FORECAST AREA. A COLD POOL OF LOW LEVEL AIR WILL BE OVER WESTERN ONTARIO WITH THE THERMAL TROUGH EXTENDING INTO WESTERN LAKE SUPERIOR. 850MB TEMPERATURES WILL LOWER TO -24C OVER THE WESTERN LAKE. LES WILL CONTINUE. HOWEVER...THE VERY COLD AIR WILL BE PARTICULARLY DRY SO DO NOT EXPECT HEAVY SNOWFALL. AT THIS TIME THE MODELS ARE NOT CALLING FOR STRONG WINDS. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... AS LOW-LEVEL WINDS BEGIN TO TAKE ON AN OVERWATER COMPONENT AHEAD OF APPROACHING COLD FRONT...MVFR CIGS AND -SHSN SHOULD DEVELOP AT KCMX WITHIN THE NEXT COUPLE OF HRS. COLD FRONT WILL PASS LATE IN THE NIGHT/EARLY MORNING...BRINGING HEAVIER LAKE EFFECT -SHSN. AROUND THE TIME OF FROPA...EXPECT A PERIOD OF MDT SNOW REDUCING VIS TO LIFR. IFR VIS IN -SHSN MAY THEN CONTINUE WELL INTO THE AFTN BEFORE IMPROVEMENT TO MVFR LATE AS WINDS VEER MORE NRLY (A LESS FAVORABLE DIRECTION FOR LAKE EFFECT -SHSN THERE). VIS SHOULD IMPROVE TO VFR IN THE EVENING AS WINDS BECOME LGT/VRBL AND -SHSN DIMINISH. AT KSAW...VFR CONDITIONS SHOULD DOMINATE UNTIL COLD FROPA LATE IN THE MORNING. AFTER FROPA...EXPECT MVFR CIGS AND POSSIBLY A FEW FLURRIES THRU THE REMAINDER OF THE FCST PERIOD...BUT WOULD NOT BE SURPRISED TO SEE SEVERAL EPISODES OF VFR CONDITIONS. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LOW PRES MOVING THROUGH NRN ONTARIO TO JAMES BAY WILL DRAG A COLD FRONT ACROSS LAKE SUPERIOR LATE TONIGHT AND WED MORNING. SW WINDS ARE EXPECTED TO INCREASE INTO THE 20-30 KT RANGE OVER THE W BY MIDNIGHT AND VEER NW AS THE FRONT MOVES THROUGH. THE WINDS WILL DIMINISH LATE WED INTO WED NIGHT AS A WEAK RIDGE BUILDS INTO THE REGION. LOW PRES MOVING TOWARD THE SOUTHERN GREAT LAKES THU WILL BRING AN INCREASE IN N WINDS TO 15 TO 25 KT. OTHERWISE...WINDS SHOULD REMAIN BLO 30 KT UNTIL A STRONGER LOW PRESSURE SYSTEM MOVES EASTWARD THROUGH NRN ONTARIO OR LAKE SUPERIOR LATE SATURDAY INTO SUNDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH LATE WED NIGHT THRU THU EVENING MIZ010>013. && $$ UPDATE...ROLFSON SHORT TERM...JLB LONG TERM...DLG AVIATION...ROLFSON MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 330 AM EST WED FEB 13 2008 .SYNOPSIS... A WARM FRONT WILL REMAIN NEARLY STATIONARY ACROSS CENTRAL NORTH CAROLINA INTO THIS MORNING. A COLD FRONT WILL MOVE SLOWLY THROUGH CENTRAL NORTH CAROLINA LATE THIS AFTERNOON THROUGH EARLY EVENING. HIGH PRESSURE WILL MOVE FROM THE TENNESSEE VALLEY ACROSS OUR AREA TO THE MID ATLANTIC COAST LATE TONIGHT THROUGH THURSDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 220 AM WEDNESDAY... THE SYNOPTIC PATTERN IS EVOLVING LARGELY AS EXPECTED EARLY THIS MORNING... WITH THE FULL LATITUDE MID LEVEL TROUGH AMPLIFYING OVER THE MISS VALLEY THEN SHARPENING AS IT SWINGS THROUGH NC TONIGHT. SEVERAL WEAK LOWS EXIST ALONG THE COLD FRONT... CURRENTLY RUNNING FROM E OH TO E TN TO S MS... AND ANOTHER LEE LOW APPEARS TO BE FORMING ALONG THE WEDGE FRONT OVER UPSTATE SC INTO THE SRN NC FOOTHILLS. DESPITE PRECIPITATION FALLING THROUGH 10-15C AIR JUST 0.5-1.0 KM ALOFT... THE STABLE WEDGE REMAINS LOCKED IN OVER THE WESTERN PIEDMONT WHERE SURFACE TEMPS HOLD IN THE LOW-MID 30S. THE WEDGE FRONT HAS MOVED LITTLE IN THE LAST SEVERAL HOURS... STRETCHING FROM JUST SE OF WADESBORO / SANFORD / RALEIGH / HALIFAX. AS ONE MIGHT EXPECT... THE LARGE SCALE MODELS ARE DEPICTING THE DETAILS OF THE WEDGE REGIME POORLY. THE RUC13 IS DOING MUCH BETTER AND IT INDICATES THAT THE STABLE POOL WILL NOT BECOME DISLODGED FROM THE FAR NW PIEDMONT PRIOR TO COLD FRONT PASSAGE. 925-850 MB WINDS ARE FROM THE SOUTH... NEARLY PARALLEL TO THE WEDGE FRONT... AND ARE EXPECTED TO VEER TO WSW AS A LOW LEVEL TROUGH... LOCATED ALONG THE AL/GA BORDER AT 00Z... PIVOTS NORTHEAST AND THROUGH THE CWA LATER THIS MORNING. ALL OF THIS MEANS THAT TEMPERATURES IN THE TRIAD ARE ONLY EXPECTED TO RISE THROUGH THE 30S... AND THAT MAY BE OPTIMISTIC... BEFORE THE COLD FRONT PUSHES THROUGH TOWARD MIDDAY... AND THE POSSIBLE DEVELOPMENT OF THE LEE LOW ALONG THE WEDGE FRONT WOULD ONLY REINFORCE THIS IDEA. TEMPERATURES IN THE SOUTHEAST HOWEVER WILL UNDOUBTEDLY HOLD IN OR RISE THROUGH THE LOW-MID 60S AS INTENSE LOW LEVEL WARM AIR ADVECTION PERSISTS. REGARDING RAIN CHANCES AND THE RISK OF SEVERE STORMS... LATEST GUIDANCE AND TRENDS ARE ON PACE WITH THE FORECAST WITH WIDESPREAD RAIN... OCCASIONALLY MODERATE AS PRECIPITABLE WATER VALUES ARE OVER 200% OF NORMAL... LASTING THROUGH THE MORNING. DYNAMIC FORCING IS STRONG WITH MODEL WIND PROGS ON THE 1.5 PVU SURFACE DEPICTING IDEALLY JUXTAPOSED POLAR AND SUBTROPICAL JETS OVER NC THIS MORNING... HOWEVER THE CHANCES OF STRONG CONVECTION AND ISOLATED SEVERE STORMS TODAY ARE HIGHLY RELIANT ON THE DEGREE OF POTENTIAL INSTABILITY. 00Z REGIONAL SOUNDINGS AND LATEST RUC-ADJUSTED PLOTS FROM SPC SHOW JUST 100 J/KG OF CAPE OR LESS (AND THIS IS ELEVATED POTENTIAL INSTABILITY WEST OF THE WEDGE FRONT) ALTHOUGH ANY ADDITIONAL BOUNDARY LAYER WARMING WILL PUMP UP THESE NUMBERS QUICKLY IN THE WARM SECTOR... AND BUFR SOUNDINGS AT FAY SHOW A FEW HUNDRED J/KG OF CAPE BY THIS AFTERNOON. OF COURSE THE LOW LEVEL STORM RELATIVE HELICITY IS OVER 500 M2/S2 NEAR AND NW OF THE WEDGE FRONT... SO IF WE CAN GET ANY DISCRETE CONVECTIVE ELEMENTS GOING... THEY`LL NEED TO BE WATCHED FOR QUICK SPINUP IF THEY TRAVERSE THIS ZONE OF HIGH VORTICITY. WILL ALSO NEED TO WATCH NEAR A SURFACE LOW CENTER EXPECTED TO SPIN UP OFF THE SC COAST THIS MORNING... ASSOCIATED WITH A MID LEVEL VORTICITY MAX NOTED ON WATER VAPOR IMAGERY TRACKING UP THE COAST. LATER TODAY... AS THE 80+ KT 500 MB JET WRAPS AROUND THE MID LEVEL LOW UP INTO ERN NC... HODOGRAPHS WILL BECOME STRONGLY LINEAR WITH 60+ KTS OF DEEP LAYER SHEAR... AND A FEW BOWING SEGMENTS MAY PRODUCE DAMAGING WIND GUSTS... MAINLY ALONG/EAST OF I-95 THIS AFTERNOON WHERE SREF PROBABILITIES OF NEGATIVE LI VALUES AND CAPES OF 500-1000 J/KG ARE BETTER THAN 50%... AND WHERE A POOL OF 100-150 M MID LEVEL HEIGHT FALLS WILL MOVE IN LATE IN THE DAY. AFTER COLD FRONTAL PASSAGE BETWEEN 2 AND 8 PM... THE LOW LEVEL COLD AIR WILL SLOWLY FILTER INTO THE CWA WITH THE TERRAIN TEMPORARILY HOLDING OFF THE HIGH BUILDING IN FROM THE WEST. THERE IS SOME CONCERN ABOUT A POSSIBLE END AS A BRIEF PERIOD OF WINTRY PRECIP TONIGHT. THE EXTENT AND SPEED OF THE COLDER AIR PUSHING IN AND THE POTENTIAL RAPID DEEPENING OF A SURFACE LOW OVER OR JUST OFF THE NE NC COAST... AS THE DEEPENING MID LEVEL LOW SHIFTS OVER THE AREA... BOTH POSE SOME CONCERN. AT THIS TIME IT LOOKS LIKE THE COLD AIR WILL LARGELY BE CHASING THE BEST MOISTURE... AND FORECAST BUFR SOUNDINGS FROM BOTH THE NAM AND GFS INDICATE WANING MOISTURE IN THE CRYSTAL GROWTH AREA ALOFT. BUT GIVEN ENOUGH DYNAMIC LIFT PRODUCED BY THE MID LEVEL LOW... THERE IS SOME POTENTIAL FOR SATURATION IN THIS AREA. BASED ON THIS... AND ON THE OVERALL VIGOROUS AND HIGHLY ANOMALOUS NATURE OF THIS SYSTEM... WILL INCLUDE A SHORT PERIOD OF INCONSEQUENTIAL RAIN/SNOW MIX IN THE NORTH BEFORE PRECIP ENDS OVERNIGHT. LOWS 28-37 ACROSS THE CWA. -GIH && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 250 AM WEDNESDAY... A CHILLY NORTH-SOUTH ORIENTED SURFACE HIGH BUILDS QUICKLY INTO AND OVER NC THURSDAY. IN THE WAKE OF THE DEPARTING MID LEVEL TROUGH... SHORTWAVE RIDGING AND STRONG SUBSIDENCE WITH A VERY DRY COLUMN WILL EQUATE TO CONSIDERABLE SUNSHINE. THE LOW LEVEL THERMAL PROFILE SUPPORTS HIGHS CLOSE TO NORMAL THURSDAY... 52-58. AS THE SURFACE HIGH SHIFTS OFFSHORE LATE THURSDAY AND RETURN FLOW COMMENCES... LOW LEVEL THICKNESSES BOUNCE UP AROUND 10-15 M ABOVE NORMAL... SUPPORTING HIGHS AROUND 61-66 WITH INCREASING HIGH CLOUDS THROUGH THE DAY. -GIH && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... OUR NEXT SIGNIFICANT STORM SYSTEM... NOW PUSHING THROUGH THE PACIFIC NW... DROPS INTO THE DESERT SOUTHWEST AND DEEPENS FRIDAY NIGHT. MEANWHILE... A NORTHERN STREAM COLD FRONT WILL DROP THROUGH THE AREA FRIDAY NIGHT. BUT WITH A PRECEDING DRY AND STABLE AIR MASS WITH DOWNSLOPE 850 MB FLOW... ALONG WITH A LACK OF SIGNIFICANT ISENTROPIC UPGLIDE OR OTHER LARGE SCALE FORCING MECHANISM... THIS FRONT SHOULD COME THROUGH LARGELY DRY BUT WITH CONSIDERABLE CLOUDINESS FRIDAY NIGHT. LOWS 34-40. LOW LEVEL THICKNESSES DROP BACK BELOW NORMAL BEHIND THE FRONT AND TEMPERATURES SHOULD FOLLOW SUIT... ONLY RISING TO 48-56 AS A POLAR SOURCE HIGH BUILDS IN FROM THE NORTH. EXPECT SKIES TO REMAIN MOSTLY CLOUDY FOR MUCH OF SATURDAY... PRIMARILY OVER SOUTHERN SECTIONS CLOSER TO THE FRONT... AS MID LEVEL MOISTURE ADVECTS ENE FROM THE SOUTHWEST LOW. THE GFS AND ECMWF CONTINUE TO PART WAYS WITH THE SPEED OF THIS STORM SYSTEM AS IT EJECTS THROUGH TX INTO THE OH VALLEY AND INTERIOR NE... ONLY NOW IT`S THE ECMWF THAT IS A TAD FASTER. BUT THEY DO SEEM TO BE CONVERGING ON A COMMON SOLUTION. THE CLOSED MID LEVEL LOW IS LIKELY TO RIDE NORTHEAST AND DAMPEN INTO A SHORTWAVE PASSING JUST TO OUR NW SUNDAY/SUNDAY NIGHT... AS THE LARGE SCALE PATTERN TRANSITIONS TO DEEP TROUGHING OVER ALL OF EASTERN NOAM. THE SURFACE HIGH CENTERED TO OUR NE IS EXPECTED TO NOSE BACK INTO THE PIEDMONT IN A DAMMING FASHION... AND AS RAIN CHANCES INCREASE SUNDAY WITH IMPROVING OVERRUNNING... A DAMMING REGIME IS LIKELY TO ENSUE. SURFACE CYCLOGENESIS IS LIKELY SOMEWHERE OVER THE WEST GULF COAST EARLY SUNDAY... AND WHILE THIS LOW IS LIKELY TO TRACK ALONG OR JUST EITHER SIDE OF THE APPALACHIANS ALONG A COLD FRONT... WHETHER IT ENDS UP AS A MILLER TYPE-A OR TYPE-B CYCLOGENESIS PATTERN IS STILL UP IN THE AIR. WILL HAVE INCREASING POPS FROM CHANCE SUNDAY TO LOW END LIKELY SUNDAY NIGHT INTO MONDAY. EXPECT BLUSTERY NW LOW LEVEL FLOW BEHIND THIS SYSTEM LATE MONDAY INTO TUESDAY WITH THE LARGE SCALE TROUGH AXIS PUSHING THROUGH... AND TEMPERATURES SHOULD BE WELL BELOW NORMAL. -GIH && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 200 AM WEDNESDAY... SHARP CONTRAST IN TEMPERATURES ACROSS THE CWA DUE IMPART TO HIGH PRESSURE WEDGED OVER THE WESTERN PORTION OF THE CWA...COOLER AIR AND WARM/STATIONARY FRONT THROUGH THE EASTERN PORTION... WARMER AIR. AS A RESULT OF THIS WEATHER PATTERN... INT AND GSO WILL HAVE LIFR CONDITIONS THROUGH THE MORNING. WITH TEMPERATURES HOVERING AROUND FREEZING THERE IS A POSSIBILITY OF SOME FREEZING RAIN. RDU WILL SERVE AS THE TRANSITION ZONE WITH LIFR TO IFR CONDITIONS... WHILE FAY AND RWI... WHO WILL BE ALONG AND EAST OF THE FRONT WILL EXPERIENCE MVFR TO IFR CONDITIONS. THE SOUTHERLY FLOW ON THE EAST SIDE OF THE FRONT WILL ENHANCE THE CHANCE FOR RAIN OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA THROUGH THE MORNING. AS THE COLD FRONT THROUGH EASTERN TENNESSEE MOVES SLOWLY EAST... THE WEDGE SHOULD WEAKEN DURING THE LATE MORNING AS THE BOUNDARY THROUGH THE CENTRAL PORTION OF THE CWA MOVES WEST... SQUEEZING OUT THE WEDGE. AS THE COLD FRONT MOVES THROUGH THE CWA MAINLY DURING THE AFTERNOON... RAIN WILL OVERSPREAD THE AREA... BRINGING THE POSSIBILITY OF MVFR TO IFR CONDITIONS SHOWERS AND ISOLATED THUNDERSTORMS. CONDITIONS WILL IMPROVE TONIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM THE WEST... HOWEVER SOME RESIDUAL LOW LEVEL MOISTURE COULD LEAD TO SOME CLOUD BASES BETWEEN 25 HUNDRED AND 5 THOUSAND FEET THROUGH EARLY THURSDAY MORNING... OTHERWISE VFR CONDITIONS WILL PREVAIL THURSDAY THROUGH EARLY FRIDAY MORNING. HIGH PRESSURE OVER THE AREA WILL MOVE EAST AND SOUTHEAST OFFSHORE FRIDAY AFTERNOON AS A LOW OVER THE NORTHEAST UNITED STATES DRIFTS EAST AND SOUTHEAST. AS MOISTURE INCREASES OVER THE AREA WITH THE PASSAGE OF THE BOUNDARY THROUGH THE AREA... MVFR CEILINGS WILL BE POSSIBLE SATURDAY NIGHT. WIDESPREAD RAIN IS POSSIBLE SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...RHJ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 335 AM EST WED FEB 13 2008 .SYNOPSIS... LOW PRESSURE WILL TRACK UP THE EAST COAST TODAY. A COLD FRONT WILL PUSH THROUGH PENNSYLVANIA ON FRIDAY. A DEVELOPING STORM SYSTEM ALONG THE GULF COAST WILL TRACK NORTHWARD TOWARDS PENNSYLVANIA BY LATE SUNDAY OR EARLY MONDAY. && .NEAR TERM /THROUGH TODAY/... RADAR SHOWING TWO DISTINCT AREAS OF PRECIP THIS MORNING. TO THE WEST...BAND OF 850-700MB FGEN /ASSOCIATED WITH JET STREAK RIGHT ENTRANCE REGION/ IS PRODUCING A BAND OF ENHANCED PRECIP ALONG COLD FRONT. MIXED PRECIP IN ADVANCE OF FRONT QUICKLY TURNING TO A PERIOD OF SNOW WITH FROPA. OVER SOUTHEAST PA...SIG ICING EVENT UNDERWAY...AS LL JET TRANSPORTING ABUNDANT MOISTURE OVR STUBBORN POOL OF COLD AIR AT SFC. SFC TEMPS HAVE BEEN RISING STEADILY OVR SE PA DURING THE LAST FEW HOURS...AND SUSPECT A CHANGEOVER TO PLAIN RAIN OVR THE LOWER SUSQ VALLEY BEFORE DAWN BASED ON LATEST RUC13 AND NAM12 SFC PROGS. WILL LIKELY BE ABLE TO CANCEL ICE STORM WARNING BEFORE IT/S 14Z EXPIRATION TIME. HAVE DECIDED TO EXTEND WINT WX ADVISORY THRU NOON FOR THE BULK OF CENTRAL PA WITH EXCEPTION OF THE SUSQ VALLEY. IN THIS REGION SREF 2M TEMPS PROGGED TO REMAIN BLW 0C UNTIL LATE AM. PRECIP ASSOCIATED WITH ABOVE MENTIONED JET ENTRANCE REGION HAS ALREADY OVERSPREAD THE NW MTNS AND SHOULD MOVE INTO THE CENTRAL MTNS ARND 12Z. LATEST OBS OVER SW PA SUGGEST PRECIP MAY BEGIN AS RAIN OVER THE LAUREL HIGHLANDS. HOWEVER...RUC13/NAM12 SUGGEST LL COLD AIR SHOULD REMAIN ENTRENCHED ELSEWHERE. RAIN/FZRA WILL TURN TO A PERIOD OF SNOW BEFORE ENDING...AS COLD FRONT PUSHES THRU LATER THIS MORNING. A LIGHT ACCUM OF ARND AN INCH OR SO SEEMS LIKELY...MAINLY OVR THE HIGHER TERRAIN OF THE ALLEGHENY FRONT NORTH AND WESTWARD. BACK EDGE OF PRECIP WILL PUSH INTO THE SUSQ VALLEY THIS AFTN AS SECONDARY SFC LO RIDES UP THE EAST COAST. MODEL SOUNDINGS SUGGEST A CHANGEOVER FROM RAIN TO SNOW LIKELY OVER THE HIGH TERRAIN OF SULLIVAN/SCHUYLKILL COUNTIES...WHERE A LIGHT ACCUM POSSIBLE. && .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/... AS MID LVL LOW CENTER CUTS OFF SOUTH OF PA THIS EVENING...CAN/T RULE OUT LINGERING LGT PRECIP OVR THE LOWER SUSQ VALLEY ASSOCIATED WITH DEFORMATION ZONE. THERMAL PROFILES AT THAT TIME BECOME COLD ENOUGH FOR A RAIN/SNOW MIX. HOWEVER...WILL KEEP POPS IN THE SLGHT CHC CATEGORY BASED ON LATEST SREF QPF PLUME DATA...WHICH SHOW LITTLE CHC OF PRECIP AFTER 00Z. RIDGING AT SFC AND ALOFT SHOULD PROVIDE FAIR AND SEASONAL CONDS THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A COLD FRONT COULD WILL BE ACCOMPANIED BY SCT SNOW SHWRS FRIDAY...MAINLY OVR THE ALLEGHENY HIGHLANDS. HIGH PRESSURE SHOULD PROVIDE FAIR AND CHILLY CONDS ON SATURDAY. MED RANGE ENS DATA CONTINUES TO SUGGEST THE CHC FOR A SIG PRECIP EVENT LATE SUNDAY OR EARLY MONDAY...AS DIGGING TROF OVR THE MIDWEST SPAWNS AN EAST COAST STORM. LATEST GEFS DATA AND OPER EC SUGGEST A PRIMARY LO TRACK WEST OF PA...WITH POSS COASTAL REDEVELOPMENT. SUCH A SCENARIO FAVORS AT LEAST SOME MIXED PRECIP OVR THE BULK OF CENTRAL PA...WITH MAINLY RAIN ACROSS THE SOUTHEAST. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... WIDESPREAD IFR AND LIFR CONDS WILL PERSIST OVERNIGHT. BANDS OF FREEZING RAIN AFFECTING SERN AND NWRN CORNERS OF CWA...MDT AND BFD TAF SITES RESPECTIVELY. ELSEWHERE VERY LOW CIGS AND SOME FOG ARE THE RULE. EXPECT THIS SCENARIO TO CHANGE ONLY SLOWLY OVER THE NEXT FEW HOURS...WITH WESTERN BAND EVENTUALLY SLIDING EAST AND AFFECTING JST...AOO...UNV AND IPT WITH SOME LIGHT FZRA BEFORE SUNRISE. SOME IMPROVEMENT ON WED AS STORM SYSTEM SLOWLY LIFTS AWAY FROM STATE. TEMPS WILL WARM AND ANY REMAINING PRECIPITATION WILL BE ON THE LIGHT SIDE. CONDITIONS MAINLY IN THE IFR AND MVFR RANGE EARLY WITH IMPROVEMENT TO WIDESPREAD MVFR SOME VFR BY LATE AFTN..AS THE COASTAL LOW TAKES OVER. THE UPR TROF PUSHES EAST OF THE AREA BY THUR WITH IMPROVEMENT XPECTED OVER MUCH OF THE AREA. SOME LOW CIGS/-SHSN MAY LINGER AT JST/BFD. A RETURN TO VFR LATER THUR INTO EARLY FRIDAY AS HIGH PRES BRIEFLY BUILDS INTO THE REGION. ANOTHER LOW PRES SYS AND ATTENDANT FRONT ARE FCST TO MOVE THRU FRI INTO SAT ACCOMPANIED BY REDUCED CIGS/VIS IN RA/SN SHWRS. LINGERING -SHSN IN THE WAKE OF THE FROPA COULD KEEP BFD/JST MVFR THRU EARLY SAT. HIGH PRESSURE MOVES IN FROM SAT AFTN THROUGH MID DAY SUNDAY BRINGING PERHAPS THE BEST CHANCE AT SOME DECENT FLYING CONDS IN THIS FCST PD. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR PAZ004>006- 010>012-017>019-024>027-033>035-037-041-042-045-046. ICE STORM WARNING UNTIL 9 AM EST THIS MORNING FOR PAZ028-036- 049>053-056>059-063>066. && $$ SYNOPSIS...FITZGERALD NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD LONG TERM...FITZGERALD AVIATION...GARTNER/MARTIN pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 346 AM EST WED FEB 13 2008 .SYNOPSIS... A COLD FRONT WILL MOVE OFF THE EAST COAST LATE TODAY...AS HIGH PRESSURE BUILDS IN FROM THE WEST. THIS AREA OF HIGH PRESSURE WILL MOVE OFFSHORE FRIDAY ALLOWING A WEAK COLD FRONT TO CROSS FRIDAY NIGHT. LOW PRESSURE ACCOMPANYING THE NEXT FRONT WILL ARRIVE FROM THE WEST TO START NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD AIR DAMMING HANGING TOUGH ACROSS THE AREA. BEST ISENTROPIC LIFT WILL OCCUR DURING THE MORNING...WITH DRY SLOT AND WEAKENING LIFT FOR THE AFTERNOON. WILL GO WITH CAT POP EARLY...THEN DECREASING TO CHC ACROSS THE NC MTNS AND SLIGHT CHC ELSEWHERE BY LATE AFTERNOON. COLD AIR MOVES INTO THE MTNS BEHIND THE FRONT TODAY...SO HAVE PRECIP TRANSITIONING FROM LIQUID TO A WINTRY MIX DURING THE DAY. EXPECT THE LOWER ELEVATIONS WILL SEE MAINLY LIQUID...WHILE THE HIGHER ELEVATIONS COULD CHANGE TO ALL SNOW. THAT SAID...QPF WILL BE VERY LIGHT. ALSO...TEMPS START OUT THE DAY QUITE WARM...SO NOT EXPECTING ANY ACCUMULATIONS ON ROADWAYS THIS AFTERNOON. ELSEWHERE...HAVE GONE WITH A TEMP AND WIND TREND THAT FOLLOWS THE RUC EARLY AND THE MAV LATE WHICH HAVE CAUGHT ON TO THE CAD. EVEN WITH THAT...HIGHS WILL BE NEAR NORMAL OUTSIDE OF THE MTNS...BUT BELOW NORMAL OVER THE MTNS. ADDITIONALLY...WINDS HAVE DIMINISHED ACROSS THE MTNS. HAVE CANCELED THE LAKE WIND ADVISORY. WINDS WILL INCREASE AND BECOME GUSTY THIS AFTERNOON. WILL LIKELY NEED AT LEAST A LAKE WIND ADVISORY. WILL NOT ISSUE WITH THIS PACKAGE THOUGH SO THERE CAN BE A BREAK BETWEEN ISSUANCES AND HOPEFULLY AVOID CONFUSION. MAY ISSUE BEFORE 7 AM AFTER LOOKING AT 06Z GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... AS OF 315 AM WEDNESDAY...MODELS CONTINUE TO ADVERTISE A LIMITED NW FLOW EVENT CONTINUING AFTER 00Z THU. LLVL MOISTURE IS A BIT OF A CONCERN AS ONLY LEVELS BELOW H92 SHOULD BE ABOVE 80 PERCENT RH...BUT NW ORTHOGONAL FLOW WILL BE STRONG THROUGH A DEEP LAYER. THE SHREF MEAN QPF STAYS ABOVE THE SPREAD THROUGH 06Z...BUT QUICKLY LESSENS RH VALUES THEREAFTER. SO...QPF AMOUNTS WERE TAKEN DOWN A TAD WITH BASICALLY LESS THAN A COUPLE TENTHS OF CONTINUING SNOWFALL EXPECTED AFTER 00Z. THE LLVL THERMAL TROF BEGINS TO MOVE NORTH AFTER 00Z AND ATTENDANT CAA WEAKENS THROUGH THE OVERNIGHT. SOUNDINGS INDICATE SHALLOW MIXING AND MOMENTUM TRANSFERS DECREASING THROUGH DAYBREAK. HOWEVER...THE FIRST PART OF THE OVERNIGHT SHOULD SEE WIND GUSTS ON THE ORDER OF 35 TO 40 KTS...DECREASING TO LESS THAN 15 KTS BY 12Z. RISING HEIGHTS DEVELOP THROUGH THE DAY THU AND FLAT H5 RIDGING PERSISTS THROUGH FRI. DECENT WAA IS NOTED BY BOTH THE NAM AND GFS BELOW H85 AND MOS GUIDANCE CONTINUES TO COME IN WARMER FOR THU MAX TEMPS. THE MAX T GRIDS WERE ADJUSTED UP A DEGREE OR TWO CWFA WIDE...WHICH WILL BE ABOUT 5 F ABOVE NORMAL. THE BIG STORY THU WILL BE HOW DRY THE ATMOS GETS. DEWPOINTS TEMPS WERE MIXED DOWN A COUPLE DEGREES AS A VERY DRY AND DEEP SUBSIDENCE LAYER MOVES INTO THE REGION. THIS BRINGS LOW RH LEVELS...BELOW 25 PERCENT...TO MOST OF THE CWFA BEGINNING AROUND 16Z AND CONTINUING THROUGH AROUND 21Z. FUEL MOISTURES ACROSS NE GA HAVE BEEN NOTED AT OR ABOVE 10 PERCENT WHICH ARE BASED OFF PRE/FROPA PRECIP...AND BASED ON THAT FACT A FIRE WEATHER WATCH WILL NOT BE ISSUED FOR NE GA. THIS WILL BE MENTIONED IN THE HWO HOWEVER. A PLEASANTLY WARM DAY IS ON TAP FRIDAY. DEEP LAYERED DRY AIR REMAINS IN PLACE AND SOUTHERLY FLOW PERSISTS WITH OFFSHORE ATLANTIC HIGH REMAINING FAIRLY STATIONARY. A DEVELOPING SOUTHERN STREAM SYSTEM WILL EJECT FEW/SCT CI OVER THE AREA DURING THE AFTERNOON...BUT TEMPS SHOULD HAVE NO PROBLEM RISING TO AROUND 10 DEGREES ABOVE NORMAL IN THIS SET UP. NO FIRE WX CONCERNS ARE EXPECTED FRI WITH INCREASING SFC DEWPOINTS...BUT THIS WILL HAVE TO BE WATCHED FOR POSSIBLE MIXING ISSUES AND HOW QUICKLY THE MIXED LAYER MOISTENS UP. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 250 AM WEDNESDAY...THE WEAK COLD FRONT WILL MOVE FROM NORTHWEST TO SOUTHEAST ACROSS OUR FORECAST AREA FRIDAY NIGHT ACCORDING TO BOTH THE GFS AND ECMWF. WHAT LITTLE LIFT WILL BE TOWARD GEORGIA AND POPS WILL BE LOW. HIGH PRESSURE WILL BE OVER THE NORTHEAST STATES SATURDAY KEEPING MOST OF OUR AREA DRY...EXCEPT PERHAPS IN AND NEAR GEORGIA. THE CLOSED OFF UPPER LOW AND DEVELOPING SURFACE LOW OVER TEXAS SATURDAY NIGHT WILL BEGIN MOVING NORTHEAST AND MOISTURE WILL INCREASE ACROSS OUR AREA THROUGH EARLY MONDAY. THE ECMWF HAS A DEEPER LOW AND DRAWS MORE GULF MOISTURE WITH HIGHER QPF AMOUNTS AHEAD OF THE LOW AS IT TRACKS ACROSS THE SOUTHEAST. THE GFS HAS THE LOW OVER NORTHWEST GEORGIA AT 00Z MONDAY AND THE ECMWF HAS IT OVER KENTUCKY AT THAT TIME. THE LOW WILL MOVE NORTHEAST UP THE APPALACHIANS SUNDAY NIGHT WITH THE FRONT CROSSING US FROM WEST TO EAST EARLY MONDAY WITH DRIER AIR COMING IN FROM THE WEST DURING THE DAY ON MONDAY. HOWEVER...WRAP AROUND MOISTURE WILL REMAIN IN THE NC MOUNTAINS THROUGH EARLY TUESDAY WITH SNOW SHOWERS AS THE UPPER TROUGH CROSSES BRINGING THE LOW THICKNESSES. THE GFS DRIES OUT ALL MOISTURE FOR SNOW SHOWERS BY TUESDAY AFTERNOON...HOWEVER...THE ECMWF BRINGS IN ANOTHER STRONG SHORTWAVE ACROSS THE NORTH WITH GOOD MOISTURE AGAIN FOR NC MOUNTAIN SNOW SHOWERS. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... COMPLICATED FORECAST THIS PERIOD WITH WEDGE FULLY ENTRENCHED ACROSS THE NC FOOTHILLS/PIEDMONT AND ERN UPSTATE. VFR CONDITIONS OVER THE REST OF THE UPSTATE AND NC MTNS. EXPECT IFR OR LOWER TO CONTINUE TO DAYBREAK WHERE IT IS ALREADY OCCURRING. IFR SHOULD MOVE INTO THE WESTERN TAFS AS THE COLD FRONT MOVES IN AND MOISTURE AND PRECIP INCREASE. CONDITIONS WILL IMPROVE THROUGH THE MORNING AS THE COLD FRONT CROSSES THE AREA. CONDITIONS WILL BE SLOWER TO IMPROVE ACROSS THE NC SITES...AND WILL LIKELY NOT GO VFR UNTIL AFTERNOON. WINDS WILL BECOME WESTERLY AS THE FRONT MOVES THRU. WINDS WILL ALSO INCREASE IN SPEED AND BECOME GUSTY FOR THE AFTERNOON AND POSSIBLY EARLY EVENING. AVIATION OUTLOOK...DRY HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE REGION ON FRIDAY...WITH TEMPO MVFR CIGS AND SCATTERED SHOWERS POSSIBLE. A DEEP LOW IS EXPECTED TO FORM ALONG THE FRONT NEAR THE GULF COAST OVER THE WEEKEND...AND WIDESPREAD CIG AND VSBY RESTRICTIONS COULD FORM LATE IN THE WEEKEND AS THE LOW APPROACHES THE AREA. && .FIRE WEATHER... VERY DRY AIR THROUGH A DEEP LAYER WILL DEVELOP ACROSS THE CAROLINAS AND NORTHEAST GEORGIA EARLY THURSDAY MORNING AND THROUGHOUT THE DAY. SURFACE DEWPOINTS ARE EXPECTED TO MIX INTO THE MID TEENS ACROSS THE REGION WHILE TEMPERATURES RISE A FEW DEGREES ABOVE NORMAL. THIS WILL CREATE RELATIVE HUMIDITY VALUES LESS THAN 25 PERCENT ACROSS THE MAJORITY OF THE FORECAST AREA...WITH LEVELS BELOW 20 PERCENT PROBABLE ACROSS NORTHEAST GEORGIA. RIDGING ALOFT AND BROAD A SFC PRESSURE GRADIENT WILL KEEP SFC WINDS BELOW 10 MPH AND THE LATEST OBSERVED FUEL MOISTURES REMAIN AT 10 PERCENT OR GREATER ACROSS NE GA....SO NO FIRE WEATHER WATCH WILL BE ISSUED. WITH LATEST PRECIPITATION ACROSS NE GA....LATER SHIFTS WILL DETERMINE WHETHER OR NOT FUEL MOISTURES WILL BE LOW ENOUGH FOR A STATEMENT OR WARNING. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...DEO NEAR TERM...RWH SHORT TERM...SBK LONG TERM...DEO AVIATION...RWH FIRE WEATHER...SBK sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPOKANE WA 1000 PM PST TUE FEB 12 2008 .SYNOPSIS... A VIGOROUS COLD FRONT WILL BRING PRECIPITATION TO THE INLAND NORTHWEST THIS EVENING...FOLLOWED BY WINDY CONDITIONS OVERNIGHT. AN UPPER LEVEL RIDGE WILL RETURN FOR THE LATER HALF OF THE WEEK...WITH ONLY MINOR STORM SYSTEMS EXPECTED THROUGH THE WEEKEND. && .DISCUSSION... REST OF TONIGHT...COLD FRONT CONTINUES TO MAKE STEADY EASTWARD PROGRESS THROUGH THE INLAND NORTHWEST. THE LATEST RADAR IMAGERY SUGGESTS THE BACK EDGE OF THE STRATIFORM FRONTAL BAND EXTENDS ALONG A LINE FROM SANDPOINT TO THE TRI-CITIES...WITH SCATTERED SHOWER ACTIVITY BEHIND IT. MOST OF THE SHOWERS PER IR SATELLITE PIX WERE OCCURRING OVER THE NORTHERN TIER OF ZONES EXTENDING FROM BONNERS FERRY AND INTO THE OKANOGAN HIGHLANDS. A MORE IMPRESSIVE BAND OF SHOWERS WAS CLUSTERED ALONG THE CASCADES EXTENDING NORTH FROM WENATCHEE TO THE CANADIAN BORDER. THIS BATCH OF SHOWERS SEEMED TO BE ASSOCIATED WITH A SHORTWAVE TROF CENTERED JUST NORTH OF LAKE CHELAN AS WELL AS A FLEDGLING PUGET SOUND CONVERGENCE ZONE. THE RUC SEEMS TO BE HANDLING THE SHORTWAVE QUITE WELL AND TAKES IT ALONG THE CANADIAN BORDER THROUGH 09Z OR SO. THUS WE EXPECT THE CHANCE OF POST- FRONTAL SHOWERS TO GENERALLY PERSIST ACROSS THE NORTHERN ZONES. 500 MB TEMPS ASSOCIATED WITH THIS FEATURE HAVE BEEN DROPPING RAPIDLY WITH -32C AT UIL REPORTED ON THE EVENING SOUNDING ROUNDUP AND A REPORT OF -34C AT 03Z FROM AN MDCRS REPORT JUST NORTH OF STAMPEDE PASS. THIS REPORT FITS NICELY WITH LATEST RUC FORECAST WHICH TAKES THIS COLD POOL ACROSS THE NORTHERN ZONES OVERNIGHT...BEFORE SLOWLY SAGGING IT SOUTHWARD. THESE TEMPS COMBINED WITH BOUNDARY LAYER CONDITIONS SUPPORT VERY STEEP LAPSE RATES AND SUGGEST A SMALL CHANCE OF THUNDERSTORMS. THE ONLY THING HOLDING BACK THE FORMATION COULD BE THE LACK OF SIGNIFICANT WATER OR SUPER-COOLED WATER DROPLETS NECESSARY FOR CHARGE SEPARATION AT CLOUD BASE LEVEL. DO NOT FEEL THE THREAT OF THUNDER IS GREAT ENOUGH TO PLACE INTO THE GRIDS AT THE MOMENT. OTHER CONCERN THIS EVENING IS THE WINDS ASSOCIATED WITH THE PASSAGE OF THE SURFACE COLD FRONT. LATEST ISALLOBARIC ANALYSIS SUGGESTS THE FRONT HAS PASSED THE CASCADES AND WAS NOW MOVING INTO THE EASTERN COLUMBIA BASIN. WE HAVE RECEIVED A FEW SPOTTER REPORTS OF WINDS GUSTING TO 40 MPH NEAR THE WENATCHEE AREA...WHICH CORRELATES WELL WITH THE BEST DARKENING OBSERVED ON THE LATEST WATER VAPOR PIX. WIND GRIDS HAVE BEEN ADJUSTED ACCORDINGLY. FX .AVIATION... VFR CONDITIONS WILL GENERALLY PREVAIL AT THE TAF SITES THROUGH 06Z THU. ONLY EXCEPTIONS COULD BRIEFLY OCCUR AT PUW THRU 08Z DUE TO THE PRESENCE OF A SLOW MOVING COLD FRONT AND ITS ASSOCIATED PRECIPTIATION. SCT -SHRA/-SHSN COULD ALSO PRODUCE MTN OBSCURATIONS JUST SOUTH OF THE CANADIAN BORDER AND OVER THE ID PANHANDLE THROUGH 18Z. FX && .PRELIMINARY POINT TEMPS/POPS... SPOKANE 31 41 23 38 26 41 / 50 0 0 0 0 0 COEUR D`ALENE 32 40 25 38 25 41 / 60 10 10 0 0 10 PULLMAN 32 38 25 39 26 43 / 80 20 10 0 0 0 LEWISTON 36 46 30 45 30 49 / 50 20 10 0 0 0 COLVILLE 28 43 17 41 23 41 / 70 10 10 0 0 10 SANDPOINT 31 39 22 39 26 40 / 90 20 10 10 0 10 KELLOGG 30 35 24 37 23 40 / 100 40 20 10 10 10 MOSES LAKE 30 45 22 42 24 45 / 10 0 0 0 0 0 WENATCHEE 32 47 27 44 29 46 / 20 0 0 0 0 0 OMAK 26 41 18 38 23 41 / 10 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...NONE. WA...NONE. && $$ wa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1118 AM EST WED FEB 13 2008 .SYNOPSIS... DUAL COASTAL LOW PRESSURE CENTERS IN NJ AND SE VIRGINIA LATE THIS MORNING WILL AFFECT SOUTHERN NEW ENGLAND THROUGH TONIGHT EVENTUALLY PASSING E OF CAPE COD THU MORNING. WEAK HIGH PRESSURE MOVES ACROSS THE REGION LATE THURSDAY. LOW PRESSURE MOVING THROUGH THE ST LAWRENCE VALLEY WILL SWING A COLD FRONT THROUGH NEW ENGLAND LATE FRIDAY. NOTABLY COLD HIGH PRESSURE WILL MOVE THROUGH THE NORTHEAST SATURDAY. ANOTHER LOW PRESSURE AREA WILL APPROACH SUNDAY EVENING BRINGING MORE SNOW ICE AND RAIN SUNDAY NIGHT AND MONDAY. COLD UNSTABLE AIR MOVES IN FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 939-49 AM UPDATES FOR HEADLINES. RECORD BREAKING PCPN POSSIBLE TODAY AT BDL. SKYWARN IS COMING INTO THE OFFICE FOR MULTI REPORTS. KEEPING THIS SIMPLE...WILL UPDATE THE GRIDS AS FAST AS CONFIDENT OF ADJUSTMENTS. ICING REDUCING SCOPE OF COVERAGE NOW BASICALLY A FEW HIGH TERRAIN LOCATIONS W AND CENTRAL MASS INTO THE MONADNOCKS. MAIN BRUNT OF THE SNOW AND ICE IS DONE. WILL CANCEL MOST OF WSW AT NOON EXCPT CHESHIRE AND FRNAKLIN COUNTY HIGH TERRAIN. OKX VWP HAS 55 KTS AT 250M 57KTS DOWN FM EARLIER. YET GUSTING ONLY 35KTS AT THE SFC. SEE HYDRO SECTIONS...FLS`S/FFW ETC AS POSTED. A WIND ADVISORY CONTINUES FOR NANTUCKET AND CAPE COD TODAY. 40-45 KT GUSTS ARE POSSIBLE MAINLY THIS AFTERNOON AHEAD OF THE DEVELOPING LOW. THE WIND ADVISORY MAY NEED TO BE EXPANDED ALONG THE SOUTHERN MASSACHUSETTS COAST...BUT GIVEN THE EXPECTED TRACK ACROSS BUZZARDS BAY AND CAPE COD...DID NOT FEEL CONFIDENT TO EXPAND ANY FURTHER WEST AT THIS TIME. AN ISOLATED THUNDERSTORM IS NOT OUT OF THE QUESTION ALONG THE SOUTH COAST AND ACROSS THE CAPE AND ISLANDS BETWEEN 19Z AND 23Z TODAY. IF THIS OCCURS WILL NEED TO MONITOR FOR POTENTIAL SMW CRITERIA. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... RAIN MAY BRIEFLY END AS A PERIOD OF WET SNOW AS LOW PRESSURE DEPARTS FOR THE CANADIAN MARITIMES. OTHERWISE ANOTHER AREA OF LOW PRESSURE WILL FORM OFF THE MID ATLANTIC COAST...TRACKING FURTHER SOUTH THAN ITS PREDECESSOR. CONFINED POPS MAINLY ALONG THE SOUTH COAST...CAPE COD AND THE ISLANDS...NEAR THE REGION OF BEST MID LEVEL FRONTOGENESIS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... SOME UNCERTAINTY THURSDAY MORNING AS THE OPERATIONAL GFS AND THE NAM INDICATE A TRAILING LOW OFF THE COAST WITH RAIN LINGERING IN THE COASTAL PLAIN WHILE THE GFS ENSEMBLE AND OTHER MODELS SHOW A WEAK WAVE FARTHER OFFSHORE. WE KEPT SOME LINGERING CHANCE OF RAIN THURSDAY MORNING FOR THE SOUTHEAST ZONES...AND ESPECIALLY FOR THE CAPE AND ISLANDS. HIGH PRESSURE THEN BUILDS IN DURING THE AFTERNOON BRINGING DRY WEATHER. THE UPPER FLOW REMAINS WEST TO SOUTHWEST SO NO DRASTIC COOL DOWN IS EXPECTED FOR THURSDAY. THE HIGH MOVES OFFSHORE BY FRIDAY MORNING WITH A CLIPPER LOW IN THE ST LAWRENCE VALLEY SWINGING A COLD FRONT THROUGH THE NORTHEAST. TIMING AMONGST THE MODELS IS SIMILAR WITH THE FRONT ON A BOSTON-NEW YORK AXIS IN THE EVENING. MOISTURE LOOKS LIMITED BUT WITH FAVORABLE UPPER DYNAMICS...SO WE WILL GO WITH CHANCE POPS. PTYPE WILL BE RAIN SHOWERS LEADING THE FRONT...AND SNOW SHOWERS IN THE COLDER AIR TRAILING THE FRONT. STRONG PRESSURE RISES BEHIND THE FRONT WILL AID IN BRINGING STRONG WINDS FRIDAY NIGHT...WHICH IN TURN WILL BRING MUCH COLDER AIR TO THE REGION. THIS COLDER AIR WILL ALSO BE SUPPORTED BY A CHANGE IN THE UPPER WINDS TO NORTHWEST ON SATURDAY. 850 MB TEMPS WILL DROP FROM AROUND 0C ON FRIDAY AFTERNOON TO AROUND -16C SATURDAY AFTERNOON. SO MAX TEMPS ON SATURDAY SHOULD BE IN THE 20S...EXCEPT TEENS IN SOUTHERN NH AND NORTHWEST MASS. TWO SYSTEMS COME AT US LATE SUNDAY AND SUNDAY NIGHT...ONE FROM THE GREAT LAKES AND ONE FROM THE GULF COAST. THE GULF SYSTEM LOOKS TO BE THE CONTROLLING SYSTEM...SPREADING PRECIP INTO NEW ENGLAND SUNDAY NIGHT THROUGH MONDAY. WITH CLOUDS MOVING IN BY EVENING AND NO SOURCE OF COLD AIR IN PLACE TO OUR NORTH...WE EXPECT TEMPERATURES TO DIP A LITTLE IN THE EVENING BUT THEN SLOWLY RISE OVERNIGHT. PTYPE MAY START AS SNOW OR FREEZING RAIN ESPECIALLY IN THE INTERIOR...BUT THE OVERALL TREND WILL BE TOWARD RAIN. BEHIND THE STORM WILL BE ANOTHER BURST OF COLD ADVECTION WITH 850 MB TEMPERATURES AROUND -20C AND A LINGERING COLD POOL/UPPER TROF COMBINATION THROUGH WEDNESDAY. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... TODAY...IFR/LIFR IN RAIN...OCCASIONALLY HEAVY...WITH ISOLATED THUNDER MAINLY SOUTH COAST AND CAPE COD. LLWS ACK/HYA AND POSSIBLY PVD WITH STRONG SOUTHERLY LOW LEVEL JET. WIND GUSTS TO 40 KT POSSIBLE AT KACK. 250M WINDS AT OKX 55 KTS...YET TRANSLATES TO ONLY G35KTS AT THE SFC... FUNCTION OF INVERSION AND RICHARDSON NUMBER. ICE FREE WIND SENSOR PBLMS FORCING TO ADD NIL AMD TO ORH. WE WILL AMD ORH AND ANY OTHER NIL AMDS AS TIME AND CONFIDENCE DICTATES. TONIGHT...IFR CONDITIONS IN EVENING RAIN...MAINLY EASTERN AND SOUTHEASTERN TERMINALS. THEN MVFR/VFR CEILINGS. OUTLOOK...THURSDAY THROUGH SUNDAY... LINGERING IFR ON THE CAPE AND ISLANDS THURSDAY MORNING...OTHERWISE VFR THURSDAY AND EARLY FRIDAY. MVFR OR IFR IN SCATTERED RAIN AND SNOW SHOWERS FRIDAY AFTERNOON AND NIGHT. COLD WINDS PICKING UP FROM THE NORTHWEST FRIDAY NIGHT AND SATURDAY. WINDS DIMINISH SATURDAY AFTERNOON WITH VFR THROUGH SUNDAY MIDDAY. LOWERING CIGS DURING SUNDAY AFTERNOON AND EVENING WITH MVFR/IFR IN SNOW AND RAIN SUNDAY NIGHT. && .MARINE... TODAY...HEAVY RAIN WILL LEAD TO A REDUCTION IN VISIBILITY AT TIMES. SOUTHERLY GALES FOR THE SOUTHEASTERN COASTAL WATERS THIS AFTERNOON WITH INCREASING WINDS AS THE LOW MOVES ACROSS CAPE COD. ISOLATED TSRA POSSIBLE THIS AFTERNOON AND EARLY EVENING. TONIGHT...SCA CONDITIONS ACROSS MOST OF THE WATERS...MAINLY FOR SOUTHERLY SWELL WITH EVENING WIND GUSTS TO 25 TO 30 KT. SHIFTING WINDS TO NORTHWEST. OUTLOOK...THURSDAY THROUGH SUNDAY... NORTHWEST WINDS NEAR GALE FORCE THURSDAY MORNING WITH DIMINISHING WIND AND SEAS LATER IN THE DAY AND AT NIGHT AS HIGH PRESSURE MOVES OVERHEAD. INCREASING SOUTHWEST FLOW FRIDAY AS A COLD FRONT APPROACHES. AFTER THE FRONT MOVES THROUGH...NORTHWEST WINDS WILL INCREASE TO NEAR GALE FORCE AGAIN FRIDAY NIGHT AND EARLY SATURDAY. WINDS AND SEAS WILL THEN SUBSIDE AGAIN DURING THE DAY SATURDAY. AREAS OF FREEZING SPRAY ARE POSSIBLE FRIDAY NIGHT AND SATURDAY. ANOTHER STORM FROM THE GULF OF MEXICO WILL BRING SMALL CRAFT ADVISORY WINDS AND SEAS SUNDAY NIGHT WITH GUSTS APPROACHING GALES ON THE OUTER WATERS. && .HYDROLOGY... UPDATED 10 AM WED PLS SEE ON GOING STMTS AND WARNINGS FOR LATEST INFO. FLOOD WATCH REMAINS POSTED FROM NORTHERN CT AND RI INTO S CENTRAL AND EASTERN MA AND PART OF SW NH INTO THU MORNING. HEAVIEST RAINFALL WAS CENTERED OVER CT VALLEY REGION LATE THIS MORNING AND NAM/RUC HAVE A GOOD HANDLE ON IT. BOTH MODELS SHIFT THIS AXIS INTO RI AND EASTERN MA THIS AFTERNOON...WHERE WE WILL ALSO HAVE SOME RUNOFF CONTRIBUTION FROM SNOW MELT DUE TO TEMPERATURES WELL UP INTO 40S AND EVEN LOWER 50S. COLDER AIR IS EXPECTED TO REMAIN IN PLACE ACROSS INTERIOR WHICH WILL LIMIT SNOW MELT. RAINFALL TOTALS OF 1.5 TO 2.5 INCHES ARE EXPECTED BY EARLY TONIGHT. IN ADDITION TO SIGNIFICANT URBAN AND POOR DRAINAGE FLOODING...WE ARE ALSO CONCERNED ABOUT MINOR FLOODING ON SEVERAL SMALLER RIVERS IN PARTS OF RI AND EASTERN MA. BASED UPON COORDINATION WITH NERFC...WE ARE WATCHING THE FOLLOWING FORECAST POINTS WHICH MAY GO INTO MINOR FLOOD EITHER TONIGHT OR EARLY THU MORNING: ASSABET RIVER AT MAYNARD MA SUDBURY RIVER AT SAXONVILLE MA BLACKSTONE RIVER AT WOONSOCKET RI PAWTUXET RIVER AT CRANSTON RI IN ADDITION...MANY OTHER SMALLER RIVERS IN CENTRAL AND EASTERN MA ARE EXPECTED TO CREST ABOVE THEIR ACTION STAGES BUT BELOW FLOOD STAGE...PRIMARILY IN LOWER MERRIMACK AND SOUTHERN NEW ENGLAND BASINS. PLEASE REFER TO THE DAILY RIVER AND LAKE SUMMARY /RVDBOX OR FGUS51 KBOX/ FOR SPECIFIC FORECASTS WHICH WILL BE UPDATED BY MIDDAY. && .CLIMATE... DAILY RECORD PRECIPITATION FOR FEBRUARY 13TH BOSTON 1.65 1966 PROVIDENCE 2.59 1966 HARTFORD 1.69 1966 WORCESTER 3.16 1900 FEBRUARY 12TH 2006 WE HAD RECORD SNOWFALL BDL 21.9 AND ALSO GREATEST EVER. BOS 17.5 ORH 16.9 PVD 9.4 .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MAZ002>004-008>012-026. FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ022-024. NH...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NHZ011- 015. FLOOD WATCH THROUGH THURSDAY MORNING FOR NHZ012. RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230>237-250. GALE WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EST THIS EVENING FOR ANZ254-255. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MAZ002>004-008>012-026. FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ022>024. NH...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NHZ011- 015. FLOOD WATCH THROUGH THURSDAY MORNING FOR NHZ012. RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230>237-250. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR ANZ254-255. && $$ SYNOPSIS...WTB/DRAG NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...WTB AVIATION...DRAG MARINE...DRAG HYDROLOGY... CLIMATE... ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1008 AM EST WED FEB 13 2008 .SYNOPSIS... COASTAL LOW PRESSURE NEAR THE CAROLINAS WILL MOVE UP THE COAST TODAY AND CROSS CAPE COD THIS EVENING. WEAK HIGH PRESSURE MOVES ACROSS THE REGION THURSDAY. LOW PRESSURE MOVING THROUGH THE ST LAWRENCE VALLEY WILL SWING A COLD FRONT THROUGH NEW ENGLAND LATE FRIDAY. COLD HIGH PRESSURE WILL MOVE THROUGH THE NORTHEAST SATURDAY AND THEN MOVE EAST ON SUNDAY. ANOTHER LOW PRESSURE AREA WILL APPROACH SUNDAY EVENING BRINGING MORE SNOW AND RAIN SUNDAY NIGHT AND MONDAY. COLD UNSTABLE AIR MOVES IN FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 939 AM UPDATE FOR HEADLINES. RECORD BREAKING WATER EQUIVALENT PCPN POSSIBLE TODAY AT BDL. LOTS OF WEATHER FACTORS TO CONSIDER TODAY. WARMER AIR CONTINUED TO PENETRATE SOUTHERN NEW ENGLAND AS A WARM FRONT WAS LIFTING NORTH THIS MORNING. RADAR AND SURFACE OBSERVATIONS CONTINUE TO INDICATE A LARGE AREA OF MOSTLY FREEZING RAIN AND SLEET OVER INTERIOR SOUTHERN NEW ENGLAND...WITH LIGHT RAIN ALONG THE SOUTH COAST. PRECIPITATION WAS FALLING AT A MODERATE RATE OVER THE INTERIOR...NEAR THE LOCATION OF BEST ISENTROPIC LIFT NORTH OF THE WARM FRONT. OVERALL GIVEN PRECIPITATION INTENSITY AND SURFACE TEMPERATURES WELL BELOW FREEZING ACROSS THE INTERIOR...CONTINUED WITH WINTER STORM WARNINGS ACROSS MUCH OF CENTRAL AND WESTERN MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE...MOSTLY FOR ICE. GLAZE ACCUMULATIONS WILL REACH 0.25 INCH WITH LOCALLY HIGHER AMOUNTS UP TO 0.50 INCH. MOST OF THE FREEZING RAIN ACCRETION WILL CONTINUE THIS MORNING. MOST AREAS WILL CHANGE TO PLAIN RAIN BY THIS AFTERNOON...BUT SOME PATCHES OF FREEZING RAIN MAY CONTINUE INTO EARLY AFTERNOON. DECIDED TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM WARNING ACROSS HARTFORD CONNECTICUT THROUGH 10 AM GIVEN PLUME OF STEADY FREEZING RAIN AND SURFACE TEMPERATURES BELOW FREEZING. A FLOOD WATCH CONTINUES THIS AFTERNOON THROUGH TONIGHT FOR MUCH OF SOUTHERN NEW ENGLAND. LATEST SHORT TERM GUIDANCE IN SOME DISAGREEMENT REGARDING THE PLACEMENT OF HEAVIEST QPF. PRECIPITABLE WATER VALUES WILL BECOME ANOMALOUSLY HIGH (NEARLY TROPICAL) THIS AFTERNOON AS AN 80-90KT POTENT LOW LEVEL SOUTHERLY JET ARRIVES FROM THE BAHAMAS. EXPECT HEAVY DOWNPOURS AND A GENERAL ONE TO 2.5 INCHES OF RAINFALL TODAY. THIS WILL CAUSE URBAN AND POOR DRAINAGE FLOODING AND BRING SOME STREAMS CLOSE TO BANKFUL. A WIND ADVISORY CONTINUES FOR NANTUCKET AND CAPE COD TODAY. 40-45 KT GUSTS ARE POSSIBLE MAINLY THIS AFTERNOON AHEAD OF THE DEVELOPING LOW. THE WIND ADVISORY MAY NEED TO BE EXPANDED ALONG THE SOUTHERN MASSACHUSETTS COAST...BUT GIVEN THE EXPECTED TRACK ACROSS BUZZARDS BAY AND CAPE COD...DID NOT FEEL CONFIDENT TO EXPAND ANY FURTHER WEST AT THIS TIME. AN ISOLATED THUNDERSTORM IS NOT OUT OF THE QUESTION ALONG THE SOUTH COAST AND ACROSS THE CAPE AND ISLANDS BETWEEN 19Z AND 23Z TODAY. IF THIS OCCURS WILL NEED TO MONITOR FOR POTENTIAL SMW CRITERIA. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... UPDATING AT 939 AM FOR HEADLINES TEMPS AND DEW POINTS. RAIN MAY BRIEFLY END AS A PERIOD OF WET SNOW AS LOW PRESSURE DEPARTS FOR THE CANADIAN MARITIMES. OTHERWISE ANOTHER AREA OF LOW PRESSURE WILL FORM OFF THE MID ATLANTIC COAST...TRACKING FURTHER SOUTH THAN ITS PREDECESSOR. CONFINED POPS MAINLY ALONG THE SOUTH COAST...CAPE COD AND THE ISLANDS...NEAR THE REGION OF BEST MID LEVEL FRONTOGENESIS. && .LONG TERM /FRIDAY THROUGH TUESDAY/... SOME UNCERTAINTY THURSDAY MORNING AS THE OPERATIONAL GFS AND THE NAM INDICATE A TRAILING LOW OFF THE COAST WITH RAIN LINGERING IN THE COASTAL PLAIN WHILE THE GFS ENSEMBLE AND OTHER MODELS SHOW A WEAK WAVE FARTHER OFFSHORE. WE KEPT SOME LINGERING CHANCE OF RAIN THURSDAY MORNING FOR THE SOUTHEAST ZONES...AND ESPECIALLY FOR THE CAPE AND ISLANDS. HIGH PRESSURE THEN BUILDS IN DURING THE AFTERNOON BRINGING DRY WEATHER. THE UPPER FLOW REMAINS WEST TO SOUTHWEST SO NO DRASTIC COOL DOWN IS EXPECTED FOR THURSDAY. THE HIGH MOVES OFFSHORE BY FRIDAY MORNING WITH A CLIPPER LOW IN THE ST LAWRENCE VALLEY SWINGING A COLD FRONT THROUGH THE NORTHEAST. TIMING AMONGST THE MODELS IS SIMILAR WITH THE FRONT ON A BOSTON-NEW YORK AXIS IN THE EVENING. MOISTURE LOOKS LIMITED BUT WITH FAVORABLE UPPER DYNAMICS...SO WE WILL GO WITH CHANCE POPS. PTYPE WILL BE RAIN SHOWERS LEADING THE FRONT...AND SNOW SHOWERS IN THE COLDER AIR TRAILING THE FRONT. STRONG PRESSURE RISES BEHIND THE FRONT WILL AID IN BRINGING STRONG WINDS FRIDAY NIGHT...WHICH IN TURN WILL BRING COLDER AIR TO THE REGION. THIS COLDER AIR WILL ALSO BE SUPPORTED BY A CHANGE IN THE UPPER WINDS TO NORTHWEST ON SATURDAY. 850 MB TEMPS WILL DROP FROM AROUND 0C ON FRIDAY AFTERNOON TO AROUND -16C SATURDAY AFTERNOON. SO MAX TEMPS ON SATURDAY SHOULD BE IN THE 20S...EXCEPT TEENS IN SOUTHERN NH AND NORTHWEST MASS. TWO SYSTEMS COME AT US LATE SUNDAY AND SUNDAY NIGHT...ONE FROM THE GREAT LAKES AND ONE FROM THE GULF COAST. THE GULF SYSTEM LOOKS TO BE THE CONTROLLING SYSTEM...SPREADING PRECIP INTO NEW ENGLAND SUNDAY NIGHT THROUGH MONDAY. WITH CLOUDS MOVING IN BY EVENING AND NO SOURCE OF COLD AIR IN PLACE TO OUR NORTH...WE EXPECT TEMPERATURES TO DIP A LITTLE IN THE EVENING BUT THEN SLOWLY RISE OVERNIGHT. PTYPE MAY START AS SNOW OR FREEZING RAIN ESPECIALLY IN THE INTERIOR...BUT THE OVERALL TREND WILL BE TOWARD RAIN. BEHIND THE STORM WILL BE ANOTHER BURST OF COLD ADVECTION WITH 850 MB TEMPERATURES AROUND -20C AND A LINGERING COLD POOL/UPPER TROF COMBINATION THROUGH WEDNESDAY. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... TODAY...IFR/LIFR IN RAIN...OCCASIONALLY HEAVY...WITH ISOLATED THUNDER MAINLY SOUTH COAST AND CAPE COD. LLWS ACK/HYA AND POSSIBLY PVD WITH STRONG SOUTHERLY LOW LEVEL JET. WIND GUSTS TO 40 KT POSSIBLE AT KACK. TONIGHT...IFR CONDITIONS IN EVENING RAIN...MAINLY EASTERN AND SOUTHEASTERN TERMINALS. THEN MVFR/VFR CEILINGS. OUTLOOK...THURSDAY THROUGH SUNDAY... LINGERING IFR ON THE CAPE AND ISLANDS THURSDAY MORNING...OTHERWISE VFR THURSDAY AND EARLY FRIDAY. MVFR OR IFR IN SCATTERED RAIN AND SNOW SHOWERS FRIDAY AFTERNOON AND NIGHT. COLD WINDS PICKING UP FROM THE NORTHWEST FRIDAY NIGHT AND SATURDAY. WINDS DIMINISH SATURDAY AFTERNOON WITH VFR THROUGH SUNDAY MIDDAY. LOWERING CIGS DURING SUNDAY AFTERNOON AND EVENING WITH MVFR/IFR IN SNOW AND RAIN SUNDAY NIGHT. && .MARINE... TODAY...HEAVY RAIN WILL LEAD TO A REDUCTION IN VISIBILITY AT TIMES. SOUTHERLY GALES FOR THE SOUTHEASTERN COASTAL WATERS THIS AFTERNOON WITH INCREASING WINDS AS THE LOW MOVES ACROSS CAPE COD. ISOLATED TSRA POSSIBLE THIS AFTERNOON AND EARLY EVENING. TONIGHT...SCA CONDITIONS ACROSS MOST OF THE WATERS...MAINLY FOR SOUTHERLY SWELL WITH EVENING WIND GUSTS TO 25 TO 30 KT. SHIFTING WINDS TO NORTHWEST. OUTLOOK...THURSDAY THROUGH SUNDAY... NORTHWEST WINDS NEAR GALE FORCE THURSDAY MORINNG WITH DIMINISHING WIND AND SEAS LATER IN THE DAY AND AT NIGHT AS HIGH PRESSURE MOVES OVERHEAD. INCREASING SOUTHWEST FLOW FRIDAY AS A COLD FRONT APPROACHES. AFTER THE FRONT MOVES THROUGH...NORTHWEST WINDS WILL INCREASE TO NEAR GALE FORCE AGAIN FRIDAY NIGHT AND EARLY SATURDAY. WINDS AND SEAS WILL THEN SUBSIDE AGAIN DURING THE DAY SATURDAY. AREAS OF FREEZING SPRAY ARE POSSIBLE FRIDAY NIGHT AND SATURDAY. ANOTHER STORM FROM THE GULF OF MEXICO WILL BRING SMALL CRAFT ADVISORY WINDS AND SEAS SUNDAY NIGHT WITH GUSTS APPROACHING GALES ON THE OUTER WATERS. && .HYDROLOGY... UPDATED 10 AM WED FLOOD WATCH REMAINS POSTED FROM NORTHERN CT AND RI INTO S CENTRAL AND EASTERN MA AND PART OF SW NH INTO THU MORNING. HEAVIEST RAINFALL WAS CENTERED OVER CT VALLEY REGION LATE THIS MORNING AND NAM/RUC HAVE A GOOD HANDLE ON IT. BOTH MODELS SHIFT THIS AXIS INTO RI AND EASTERN MA THIS AFTERNOON...WHERE WE WILL ALSO HAVE SOME RUNOFF CONTRIBUTION FROM SNOW MELT DUE TO TEMPERATURES WELL UP INTO 40S AND EVEN LOWER 50S. COLDER AIR IS EXPECTED TO REMAIN IN PLACE ACROSS INTERIOR WHICH WILL LIMIT SNOW MELT. RAINFALL TOTALS OF 1.5 TO 2.5 INCHES ARE EXPECTED BY EARLY TONIGHT. IN ADDITION TO SIGNIFICANT URBAN AND POOR DRAINAGE FLOODING...WE ARE ALSO CONCERNED ABOUT MINOR FLOODING ON SEVERAL SMALLER RIVERS IN PARTS OF RI AND EASTERN MA. BASED UPON COORDINATION WITH NERFC...WE ARE WATCHING THE FOLLOWING FORECAST POINTS WHICH MAY GO INTO MINOR FLOOD EITHER TONIGHT OR EARLY THU MORNING: ASSABET RIVER AT MAYNARD MA SUDBURY RIVER AT SAXONVILLE MA BLACKSTONE RIVER AT WOONSOCKET RI PAWTUXET RIVER AT CRANSTON RI IN ADDITION...MANY OTHER SMALLER RIVERS IN CENTRAL AND EASTERN MA ARE EXPECTED TO CREST ABOVE THEIR ACTION STAGES BUT BELOW FLOOD STAGE...PRIMARILY IN LOWER MERRIMACK AND SOUTHERN NEW ENGLAND BASINS. PLEASE REFER TO THE DAILY RIVER AND LAKE SUMMARY /RVDBOX OR FGUS51 KBOX/ FOR SPECIFIC FORECASTS WHICH WILL BE UPDATED BY MIDDAY. && .CLIMATE... DAILY RECORD PRECIPITATION FOR FEBRUARY 13TH BOSTON 1.65 1966 PROVIDENCE 2.59 1966 HARTFORD 1.69 1966 WORCESTER 3.16 1900 FEBRUARY 12TH 2006 WE HAD RECORD SNOWFALL BDL 21.9 AND ALSO GREATEST EVER. BOS 17.5 ORH 16.9 PVD 9.4 .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MAZ002>004-008>012-026. FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ022-024. NH...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NHZ011- 015. FLOOD WATCH THROUGH THURSDAY MORNING FOR NHZ012. RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230>237-250. GALE WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EST THIS EVENING FOR ANZ254-255. && $$ SYNOPSIS...WTB/DRAG NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...WTB AVIATION...DRAG MARINE...DRAG HYDROLOGY...JWD CLIMATE...DRAG ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 853 AM EST WED FEB 13 2008 .SYNOPSIS... A WARM FRONT ACROSS NYC AND SOUTHERN CONN...WILL WORK ITS WAY NORTHWEST THIS MORNING. IT WILL NOT MAKE IT COMPLETELY THROUGH THE REGION...AS LOW PRESSURE CONSOLIDATES INTO A SINGLE COASTAL LOW JUST OFF THE DELMARVA PENINSULA BY EARLY AFTERNOON. THIS LOW WILL THEN LIFT NORTHEAST TO THE CANADIAN MARITIME PROVINCES BY THURSDAY MORNING. A WEAK SECONDARY WILL DEVELOP NEAR THE VIRGINIA CAPES THIS EVENING...AND TRACK WELL TO OUR SOUTHEAST OVERNIGHT. WEAK HIGH PRESSURE BUILDS INTO OUR SOUTH THURSDAY AND THURSDAY NIGHT. A COLD FRONT APPROACHES FROM THE NORTHWEST FRIDAY MORNING...THEN CROSSES THE TRI-STATE FRIDAY AFTERNOON AND EVENING. HIGH PRESSURE BUILDS IN FROM THE WEST LATE FRIDAY NIGHT AND SATURDAY...THEN MOVES OFFSHORE SATURDAY NIGHT. AN AREA OF LOW PRESSURE WILL MOVE FROM THE GULF COAST STATES SUNDAY MORNING...TO THE VICINITY OF SOUTHERN NEW ENGLAND BY MONDAY MORNING...AND INT THE CANADIAN MARITIME PROVINCES THROUGH MONDAY NIGHT. HIGH PRESSURE BUILDS IN FROM THE WEST ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HAVE EXTENDED WINTER WEATHER ADVISORY FOR NORTHWEST CONN AND CENTRAL LOWER HUDSON VALLEY COUNTIES UNTIL 11 AM. WARM FRONT CONTINUES TO WORK NORTH ACROSS SE CT THIS MORNING. WITH STRONG WAA ALOFT AND WARM RAIN PROCESSES...EXPECT TEMPS ACROSS THE WARNING ADVISORY AREAS TO SLOWLY NUDGE ABOVE FREEZING THROUGH THE LATE MORNING/EARLY AFTERNOON. LATEST RUC SUGGESTS THAT LOWER HUDSON VALLEY...NE NJ...AND NW CT ZONES NEVER GET WARM FRONT THROUGH (EXCEPT FOR MAYBE HUDSON COUNTY). WILL END UP WITH VERY TIGHT TEMPERATURE GRADIENT ACROSS THE CWA AS A RESULT. OTHERWISE...ALL PRECIPITATION IS NOW IN THE FORM OF EITHER RAIN (LONG ISLAND/COASTAL CT AND METRO NYC) OR FREEZING RAIN ELSEWHERE...AS TEMPERATURES ALOFT ONLY SUPPORT LIQUID PRECIPITATION FALLING INTO THE LOWER BOUNDARY LAYER. ACROSS INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND WESTERN PASSAIC COUNTY...SUFFICIENT COLD AIR IS WEDGE IN PLACE AGAINST LOCALLY HIGHER ELEVATIONS...THAT ADDITIONAL SIGNIFICANT ICING (AN ADDITIONAL HALF TO THREE QUARTERS OF AN INCH) IS LIKELY BEFORE TEMPERATURES RISE ABOVE FREEZING TOWARDS THE END OF RUSH HOUR. AS A RESULT THE WINTER STORM WARNING HAS BEEN EXPANDED TO INCLUDE PUTNAM COUNTY. WAS A BORDER LINE CASE AS TO WHETHER TO INCLUDE NORTHERN FAIRFIELD COUNTY OR NOT...IT APPEARS HOWEVER THAT THE TRAJECTORY OF THE HEAVIEST PRECIPITATION THIS MORNING WILL ONLY CLIP THE NORTHERN TIP OF THE COUNTY...SO WILL END UP WITH A WIDE RANGE OF ICE COVERAGE...RANGING FROM A TENTH OF AN INCH JUST N OF THE I-95 CORRIDOR TO UPWARDS OF 3/4 OF AN INCH IN THE FAR NORTHERN TIP...SINCE LESS THAN HALF OF THE NORTHERN FAIRFIELD COUNTY ZONE SHOULD RECEIVE AT LEAST .5 INCHES OF ICE (THE REQUIREMENT FOR A WARNING)...HAVE LEFT AS AN ADVISORY. FOR ADVISORY AREA...HAVE EXTENDED TO 12Z. WOULD NOT BE SURPRISED IF SOME PORTIONS OF THE ADVISORY AREA ENDS UP GETTING EXTENDED AN HOUR OR SO...AS NOT COMPLETELY CONFIDENT TEMPERATURES WARM UP AS FAST AS WHAT IS FORECASTED. TEMPERATURES THIS MORNING BASED ON A BLEND OF RUC 2M TEMPERATURES (WHICH HAVE BEEN SUPERIOR SO FAR IN THESE DAMMING SITUATIONS) AND LAV NUMBERS (WHICH ALSO HAVE FAIRED FAIRLY WELL IN THESE SCENARIOS). (MORE ON TEMPERATURES LATER) NEXT ISSUE IS FLOODING POTENTIAL. HAVE EXPANDED FLASH FLOOD WATCH TO INCLUDE ORANGE AND WESTERN PASSAIC COUNTIES. GFS HAD RIGHT IDEA OF HEAVIER SLUG OF PRECIPITATION GOING OVER THOSE LOCATIONS...AND ON INTO INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND CLIPPING FAR NW CT ZONES...AS EVIDENCE BY REGIONAL RADAR...SO WITH POTENTIAL FOR SIGNIFICANT RAINFALL ON TOP OF A HALF AN INCH TO INCH OF ICE (HELPING TO MAXIMIZE RUNOFF)...HAVE A FLOOD THREAT THERE AS WELL. WHILE RAINFALL WILL BE HEAVY EVERYWHERE BY THIS AFTERNOON...HEAVIEST PRECIPITATION SHOULD BE IN A BAND FROM AROUND NYC NE INTO NE CT IN RESPONSE TO BEING IN RIGHT ENTRANCE REGION OF 160 KT JET...VERY STRONG ISENTROPIC LIFT...AND STRONG LOW LEVEL FRONTOGENIC FORCING (POSSIBLY CREATING BANDING TO LOCALLY ENHANCE PRECIPITATION). REFER TO HYDROLOGY SECTION FOR DETAILS ON RAINFALL AMOUNTS. AS FOR TEMPERATURES...ALL DEPENDANT ON HOW FAR WARM FRONT MAKES IT. WARM FRONT CURRENTLY BETWEEN BUOYS (44025 AND 44017) AND LONG ISLAND. SHOULD MAKE IT THROUGH AT LEAST EASTERN LONG ISLAND AND SE CT...AND POSSIBLY INTO NYC. NOT REAL CONFIDENT IN IT MAKING IT THROUGH MUCH ELSE...ESPECIALLY WITH LOW PRESSURE CONSOLIDATING TO THE S BY EARLY AFTERNOON. HIGHS BASED ON BLEND OF MAV/FWC/MET BLEND...WHICH WAS USED TO TAMPER WHAT LOOKED TO BE SLIGHTLY TO MUCH WARMING OVER SE AREAS FROM RUC 2M TEMPS AND LAV NUMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... GFS IS OUTLIER WITH ITS DEVELOPMENT OF A STRONG LOW TRACKING JUST TO OUR SOUTHEAST TONIGHT...LEANED TOWARDS WEAKER MORE PROGRESSIVE SOLUTION SUPPORTED BY CMC REGIONAL/NAM/SREF/ECMWF/UKMET. MAIN RESULT WAS TO SIGNIFICANTLY REDUCE POPS OVER MOST OF THE CWA TONIGHT...IF CMC REGIONAL IS RIGHT COULD END UP DRY TONIGHT. BEST CHANCE FOR PRECIPITATION IS OVER SE AREAS...WITH ONLY SLIGHT CHANCE NW. DID KEEP UP FLASH FLOOD WATCH OVERNIGHT...DUE TO RESIDUAL EFFECTS AND TO TRY TO AVOID ANY ISSUES IN CASE GFS CEASES TO BE AN OUTLIER (AM SLIGHTLY NERVOUS BECAUSE GFS HAS BEEN FORECASTING THIS IN ALL RUNS SINCE 00Z LAST NIGHT). THURSDAY AND THURSDAY NIGHT SHOULD BE DRY WITH A RIDGE BUILDING IN ALOFT. TEMPERATURES WILL BE NEAR NORMAL AS WELL. DIFFERENCE IN NAM AND GFS IN TIMING OF NEXT COLD FRONT THAT SHOULD CROSS THE REGION BEGINNING LATE ON FRIDAY. WITH SUPPORT FROM SREF AND UKMET LEANED TOWARDS FASTER GFS TIMING AND A WEAKER FRONT AS WELL. ONE CONSEQUENCE OF THE WEAKER FRONT...IS THAT THE FORCING IS WEAKER...SO HAVE SLIGHTLY LOWER POPS ON FRIDAY AS A RESULT. SHOULD BE A DECENT WARM PUSH AHEAD OF THE FRONT...WITH HIGHS FRIDAY AROUND 10 DEGREES ABOVE NORMAL. && .LONG TERM /SATURDAY THROUGH TUESDAY/... THE NEXT COLD FRONT WILL PUSH THROUGH THE AREA BY AROUND MIDNIGHT FRIDAY NIGHT. WITH THE BOUNDARY SO WARM INITIAL HAVE A CHANCE OF RAIN/SNOW SHOWERS N CHANCE OF RAIN SHOWERS S IN THE EVENING...THEN WITH SOME EVIDENCE THAT THERE WILL BE POST FRONTAL PRECIPITATION HAVE A CHANCE OF SNOW SHOWERS AT MOST LOCATIONS AFTER MIDNIGHT WITH THE COLDER AIR WORKING IN BEHIND THE FRONT. PRECIPITATION AMOUNTS ARE EXPECTED TO BE LIGHT DUE TO LIMITED MOISTURE AND THE PROGRESSIVE NATURE OF THE SYSTEM. A MORE SIGNIFICANT COASTAL STORM IS EXPECTED TO IMPACT THE AREA LATE SUNDAY THROUGH EARLY TUESDAY. TRACK REMAINS UNCERTAIN...BUT AT THIS POINT WE ARE EXPECTING A MIX OF RAIN AND SNOW ACROSS MUCH OF THE AREA. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... IFR CIGS/VSBYS WILL BE DROPPING TO LIFR TOWARDS DAYBREAK AND WILL REMAIN LIFR (POSSIBLY VLIFR) THROUGH ABOUT 22Z THIS EVENING. FZRA ACROSS KNYC TO KISP TERMINALS WILL BE CHANGING TO PLAIN RAIN OVER THE NEXT HOUR OR SO...WHILE FZRA FURTHER INLAND WILL HOLD OFF UNTIL ABOUT 08-09Z. SN AT KSWF WILL BE MIXING WITH FZRA AND PL THROUGH 08Z...THEN A PROLONGED PERIOD OF FZRA WILL BE EXPECTED THROUGH THIS MORNING. RAIN MAY BECOME HEAVY AT TIMES...RESULTING IN THE LOWERED CONDITIONS. SE WINDS AT 5-10 KT WILL BE INCREASING TO 10-15 KT (15-20 KT AT KNYC TERMINALS) TONIGHT. 60+ 2K FT LLJ KT WILL MOVE INTO THE SOUTHERN PORTION OF TH REGION THIS MORNING...RESULTING IN LLWS ISSUES. WILL EXPECT 50-60 KT WINDS AT 2K FT STARTING AT MANY TERMINALS TOWARDS DAYBREAK... INCREASING TO 60-70 KT WINDS AT 2K FT BETWEEN 10-12Z. LLWS ISSUE DIMINISH AS LOW PRES DEPARTS. CIGS/VSBYS IMPROVE TO MVFR IN THE LATE AFTERNOON/EARLY EVENING...BUT WILL KEEP THE MENTION FOR SOME SHOWERS AS UPPER TROUGH SWINGS THROUGH THE REGION. COLD FRONT SWINGS THROUGH THE REGION BETWEEN 22-02Z. WINDS TURN NW BEHIND THE FRONT AND WILL BE INCREASING TO 10-15 KT WITH GUSTS TO 20 KT DEVELOPING IN THE EVENING. KEPT THE MENTION OF MVFR VSBY DUE TO BR FOR THE EVENING...FIGURING THE COMBINATION OF CAA OVER A SATURATED GROUND WOULD PRODUCE BR. WINDS MAY BE STRONG ENOUGH TO KEEP BR FROM FORMING AND WOULD KEEP IT FROM LASTING TOO MUCH PAST THE END OF THE TAF PERIOD. OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... VFR CIGS/VSBYS THEN IN PLACE LATE TONIGHT THROUGH FRI. ANOTHER COLD FRONT WILL MOVE ACROSS THE AREA FRI NIGHT/EARLY SAT. HIGH PRES RETURNS FOR SUN. && .MARINE... SCA CONDITIONS WERE BEING OBSERVED ACROSS ALL WATERS THIS MORNING WITH GUSTS TO 25 KT AND OCEAN BUOYS 44025 AND 44017 REPORTING SEAS OF 7 AND 5 FT...RESPECTIVELY. SEAS OF 3 FT WERE BEING REPORTED ACROSS LONG ISLAND SOUND. SFC WARM FRONT OVER CENTRAL NJ AT 09Z WILL MOVE ACROSS THE WATERS BETWEEN 10Z AND 12Z. WINDS WILL VEER AROUND FROM THE SE TO SW DURING THIS TIME. FOR A BRIEF TIME...WINDS WILL DROP BELOW SCA THIS AFTERNOON AS THE PRESSURE TROUGH ASSOCIATED WITH THE COLD FRONT MOVES ACROSS THE WATERS...FROM 18Z TO 22Z. COLD ADVECTION THIS EVENING AND A STRENGTHENING NW FLOW WILL BRING WINDS BACK UP ACROSS THE COASTAL WATERS...WITH A MARGINAL GALE ON THE OCEAN AND SCA ELSEWHERE. THESE CONDITIONS WILL PREVAIL UNTIL AROUND 18Z THU. THE 00Z GFS CONTINUES TO SUPPORT A SECOND WAVE DEVELOPING ALONG THE MID ATLANTIC COAST THIS EVENING...THEN TAKING A TRACK SEVERAL HUNDRED MILES TO THE SE OF MONTAUK POINT BY 12Z THU. THE MAGNITUDE OF THIS LOW IS AN OUTLIER AMONGST THE GLOBAL MODEL SUITE AND THE GFS ENSEMBLE. THE GREATEST LIKELIHOOD OF SEEING GALE FORCE WINDS ON THE OCEAN WATERS LOOKS TO BE FROM 06Z TO 18Z THU. HI PRES BUILDS ACROSS THE WATERS THU AFT AND NIGHT...THEN EAST OF THE WATERS BY 12Z FRI. ANOTHER FRONTAL SYSTEM WILL IMPACT THE AREA FRI EVE WITH STRONG COLD ADVECTION TO FOLLOW INTO SAT MORNING WITH SCA CONDITIONS LIKELY TO RETURN ON ALL WATERS. HI PRES BUILDS BACK IN SAT AFT AND NIGHT FOLLOWED BY A STRENGTHENING RETURN FLOW ON SUN. && .HYDROLOGY... EVEN WITH MINIMAL QPF NO EXPECTED TONIGHT...STILL HAVE THE POTENTIAL FOR 1.5 (NW) TO 2.5 INCHES (BAND FROM NEAR NYC TO NE CT) OF RAINFALL TODAY WITH LOCALLY HIGHER AMOUNTS. THIS COMBINED WITH SNOW MELT OR FALLING ON TOP OF ICE ENCRUSTED SNOW...PROMOTING MORE RUNOFF THAN USUAL...PRESENT THE POTENTIAL FOR FLASH FLOODING ACROSS THE ENTIRE CWA. FLASHY RIVERS COULD STILL BE IN FLOOD THIS EVENING...PLUS RESIDUAL FLOODING IN URBAN AREAS WARRANT CONTINUING FLOOD WATCH INTO TONIGHT...EVEN THOUGH PRECIPITATION POTENTIAL IS GREATLY REDUCED. IF BANDING DOES DEVELOP...COULD END UP WITH VERY HEAVY RAINFALL RATES...OF AN INCH OR MORE AN HOUR...THIS WILL ADD TO ENHANCE POTENTIAL FOR FLASH FLOODING. AFTER THIS...NEXT POTENTIAL FOR SIGNIFICANT PRECIP IS WITH COASTAL STORM SYSTEM FOR EARLY NEXT WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ005>012. WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR CTZ005>007. NY...FLOOD WATCH THROUGH THURSDAY MORNING FOR NYZ067>081. WINTER STORM WARNING UNTIL NOON EST TODAY FOR NYZ067-068. WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR NYZ069-070. NJ...FLOOD WATCH THROUGH THURSDAY MORNING FOR NJZ002>006-011. WINTER STORM WARNING UNTIL NOON EST TODAY FOR NJZ002. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ330-335- 338-340-345. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ350- 353-355. GALE WARNING FROM 6 PM THIS EVENING TO 1 PM EST THURSDAY FOR ANZ350-353-355. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE... HYDROLOGY... ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 949 AM EST WED FEB 13 2008 .DISCUSSION... CURRENTLY-TODAY...WATER VAPOR/RUC ANALYSIS SHOWS INITIAL UPPER IMPULSE WELL NORTHEAST OF THE AREA AND JET STREAK OVER THE CENTRAL GULF STARTING TO ROUND THE BASE OF APPROACHING UPPER TROUGH. THE RUC IS STILL SHOWING SOME UPPER DIVERGENCE ACROSS THE NORTHEAST GULF BUT RADAR IS JUST SHOWING AN AREA OF SHOWERS IN ADVANCE OF COLD FRONT PUSHING THROUGH THE BIG BEND AREA. PRE FRONTAL DEEP CONVECTION HAS SHIFTED INTO SOUTH FLORIDA. HEATING AHEAD OF THE FRONT WILL BE INHIBITED BY LOW CLOUDS AND EXTENSIVE DEBRIS CLOUDS SPREADING ACROSS FROM THE GULF. WINDS HAVE VEERED SO LOW LEVEL CONVERGENCE ASSOCIATED WITH THE FRONT HAS WEAKENED. THIS SHOULD LIMIT CONVECTION DEVELOPING AHEAD OF THE FRONT. SOUTHERN AREAS ARE EXPECTED TO BE THE MOST FAVORED AS MOISTURE/HEATING WILL BE THE GREATEST THERE. MENTION OF A FEW STRONG STORMS IN THE SOUTH STILL LOOKS WARRANTED DUE TO RATHER STRONG WIND PROFILE. NORTHERN SECTIONS SHOULD MAINLY SEE SHOWERS THOUGH. ANY ZONE UPDATE WOULD BE MAINLY TO CLEAN UP WORDING AND WILL FOLLOW CLOUD/RADAR TRENDS THROUGH LATE MORNING. && .AVIATION...AREAS OF STRATUS WILL GRADUALLY DIMINISH BUT EXPECT CONSIDERABLE MID/HIGH CLOUDS TO AFFECT THE AREA. THIS WILL LIMIT HEATING SO THE COVERAGE OF SHOWERS/STORMS DEVELOPING AHEAD OF THE FRONT SHOULD BE SCATTERED...WITH MAIN STORM CHANCES BEING IN THE SOUTH WHERE THE MOST HEATING SHOULD OCCUR. EXPECT SOME WIND GUSTS TO AROUND 20 KNOTS DURING PERIODS OF HEATING/MIXING. FRONT SHOULD REACH THE CENTRAL PENINSULA AROUND 18Z AND LAKE OKEECHOBEE AROUND 00Z BUT CLEARING SHOULD HOLD OFF UNTIL EARLY EVENING. && .MARINE...STRONG PRE FRONTAL SOUTHWEST WINDS NECESSITATE ADVISORIES TODAY THEN THE WINDS WILL TURN NORTHWEST BEHIND THE FRONT AND SHOULD DECREASE LATE TONIGHT. WINDS WILL BE NORTH ON THU...THOUGH AT 10 TO 15 KNOTS AND DECREASING. && .FIRE WEATHER (PREV DISCUSSION)...A MUCH DRIER AIRMASS EXPECTED TO FILTER IN LATE TONIGHT AND INTO THURSDAY BEHIND THE COLD FRONT WILL CREATE AN EXPECTED LOW RH DURATION OVER INTERIOR SECTIONS ON THURSDAY AFTERNOON. A FIRE WEATHER WATCH IS POSTED FOR INTERIOR ZONES FOR THURSDAY. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...FIRE WEATHER WATCH THURSDAY AFTERNOON FOR INLAND VOLUSIA- NORTHERN LAKE-OKEECHOBEE-ORANGE-OSCEOLA-SEMINOLE-SOUTHERN LAKE. AM...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 11 AM EST THURSDAY FOR COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM- WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. && $$ SHORT TERM/AVIATION...LASCODY LONG TERM....BRAGAW fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 440 AM MST WED FEB 13 2008 .AVIATION... VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE PERIOD BEFORE STRONG COLD FRONT MOVES THROUGH THE AREA AFTER 06Z. MAY BE SOME POTENTIAL FOR DZ AND VISBY REDUCTIONS AS FRONT PASSES...BUT LOOKS LIKE MOST LIKELY SCENARIO IS DEVELOPMENT OF MVFR STRATUS LATE TONIGHT AT KGLD. OTHERWISE KGLD VWP CONTINUES TO SUGGEST LLWS AT KGLD WITH 35-40KTS JUST OF THE SURFACE AND THINK LLWS WILL BE A PROBLEM UNTIL LOWER ATMOSPHERE MIXES OUT AND WINDS INCREASE. && .DISCUSSION...00Z H5 ANALYSIS INDICATING VERY LARGE HEIGHT FALLS ACROSS THE PAC NW WHILE WATER VAPOR/RUC ANALYSIS SHOWING ROBUST MID/UPPER TROUGH DIGGING INTO THE PAC NW/NORTHERN INTERMOUNTAIN REGION EARLY THIS MORNING. AHEAD OF THIS TROUGH...SHORTWAVE RIDGING WILL BUILD OVER THE CENTRAL HIGH PLAINS WITH PRESSURE FALLS OVER NORTHEAST COLORADO LATE IN THE PERIOD. AS THE PRESSURE GRADIENT TIGHTENS...SOUTHERLY SFC WINDS WILL INCREASE TO 20-30 MPH ACROSS THE AREA TODAY. A SOUTHWEST COMPONENT WEIGHTED ACROSS THE WESTERN ZONES MAY LEAD TO A FEW LOCATIONS REACHING 60 DEGREES. ANOTHER BLAST OF ARCTIC AIR IS EXPECTED TO BUILD INTO THE NORTHERN PLAINS ON THURSDAY...HOWEVER THE H85 THERMAL TROUGH WILL REMAIN NORTH AND EAST OF THE CENTRAL HIGH PLAINS WITH MODIFIED ARCTIC AIR EXPECTED AT THIS TIME. LITTLE IF ANY INSOLATION IS EXPECTED WITH STRONG LOW LEVEL CAA IN POST-FRONTAL REGIME. A PERIOD OF POST-FRONTAL SNOW STILL APPEARS ON TRACK WEIGHTED ACROSS THE WESTERN ZONES AFTER 09-11Z AS H7 BAROCLINIC ZONE MOVES THROUGH THE AREA AND TRANSIENT AREA OF MID LVL FRONTOGENESIS IS JUXTAPOSED WITH STRONGER LARGE SCALE FORCING FOR ASCENT EVIDENT IN THE H5-H3 DIV Q FIELDS. CROSS-SECTIONS OF GEO MOMENTUM/EQUIV POT TEMP TAKEN NORMAL TO H85-H3 THICKNESS SUGGEST THE BEST RESPONSE TO THE FORCING WILL BE ACROSS EASTERN COLORADO GENERALLY WEST OF THE FORECAST AREA AND WILL KEEP THE HIGHEST ACCUMULATIONS (1-2 INCHES) WEIGHTED OVER THE THE FAR WESTERN ZONES. A FEW FLURRIES MAY LINGER INTO THE EVENING HOURS ON THURSDAY BEFORE SUBSIDENCE BUILDS OVER THE REGION WITH A COLD NIGHT EXPECTED. HIGHS ON FRIDAY WILL BE CHALLENGING AS THE ARCTIC COLD FRONT MAY BISECT THE AREA LEADING TO LARGE TEMPERATURE DIFFERENCES. WILL GENERALLY FOLLOW THE PREVIOUS FORECAST WITH HIGHS RANGING FROM AROUND 40 NORTHWEST TO AROUND 30 EAST. DAYS 4 THROUGH 7...NO CHANGES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ JRM/MCGUIRE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 448 AM CST WED FEB 13 2008 .SHORT TERM... AFTER THE WIDESPREAD SEVERE WEATHER EVENT YESTERDAY...MUCH COOLER AND DRIER HAS FILTERED INTO THE AREA WITH TEMPERATURES IN THE 30S AND 40S AND DEWPOINTS IN THE 20S AND 30S. DESPITE THE DRIER AIR...LOW CLOUDS HAVE PERSISTED ACROSS THE EASTERN THIRD OF THE AREA. LATEST SATELLITE IMAGERY AND MODEL TIME HEIGHT TRENDS INDICATE THIS CLOUD COVER SHOULD THIN AND DISSIPATE BY THIS AFTERNOON...SO WILL CALL FOR SUNNY SKIES IN MOST AREAS TODAY AND HIGHS IN THE 50S. PLEASANT WEATHER WITH A SLIGHT WARMING TREND EXPECTED TOMORROW BEFORE CHANGES BEGIN. .LONG TERM... MODEL CONSENSUS HAS IMPROVED SOMEWHAT FOR THE WEEKEND FORECAST FROM FRIDAY THROUGH SUNDAY BUT CONFIDENCE REMAINS LOW IN THE DETAILS. GFS AND ECMWF INDICATE A STRONG H5 SHORTWAVE TROUGH OVER THE PACIFIC NORTHWEST WILL CUTOFF FROM THE MAIN JETSTREAM IN THE SOUTHWEST CONUS BY FRIDAY...WITH THE SYSTEM MOVING ONLY SLOWLY EASTWARD INTO TEXAS THROUGH SATURDAY BEFORE EJECTING RAPIDLY EASTWARD ACROSS OUR REGION ON SUNDAY AS AN INTENSE 90KT+ JET DIVES SOUTHWARD ACROSS THE CENTRAL PLAINS. THIS PATTERN WILL CREATE FAIRLY STRONG WIND FIELDS AND DIVERGENT FLOW ALOFT ACROSS OUR NECK OF THE WOODS FOR THE FRIDAY TO SUNDAY TIMEFRAME. AT THE SURFACE...A CANADIAN COLD FRONT WILL PUSH SOUTHWARD ACROSS THE PLAINS STATES TOWARDS SOUTHEAST TEXAS AND LOUISIANA BY FRIDAY EVENING. AT THAT POINT...MODELS DIFFER SIGNIFICANTLY WITH GFS AND NAM INDICATING FRONT WILL CONTINUE PUSHING SOUTHEASTWARD ACROSS THE AREA INTO THE GULF BY SATURDAY...BUT ECMWF SHOWING FRONT STALLING JUST TO THE NORTHWEST OF THE AREA WHICH KEEPS US IN THE WARM SECTOR THROUGH SUNDAY. THIS OF COURSE WILL HAVE A POSSIBLE SIGNIFICANT IMPACT ON TEMPS DEPENDING ON WHICH MODEL SOLUTION PANS OUT. HAVE LEANED TOWARDS THE GFS FOR NOW...WITH COOLER TEMPS IN THE CARDS FOR SATURDAY AND SUNDAY. AS FOR PRECIP...BOTH MODEL SOLUTIONS SUGGEST EXPECTED WAA INTERACTING WITH LIFT AND FORCING ASSOCIATED WITH FRONTAL BOUNDARY WILL SPAWN NUMEROUS SHOWERS AND THUNDERSTORMS FOR MUCH OF THE FRIDAY TO SUNDAY PERIOD. HAVE KEPT LIKELY POPS GOING FOR THE WEEKEND. HPC GUIDANCE INDICATES WIDESPREAD 1 TO 3 INCH RAINFALL TOTALS OVER THE WEEKEND...AND WITH RECENT RAINS THIS MAY LEAD TO LOCALIZED FLOODING OR POSSIBLE RISES TO NEAR FLOOD STAGE ON SOME AREA RIVERS. IN ADDITION...MODEL SOLUTIONS INDICATE A FEW STRONG STORMS MAY BE POSSIBLE ON FRIDAY WITH THE INITIAL COLD FRONTAL PUSH...AND ON SUNDAY AS THE CUTOFF LOW EJECTS EASTWARD. SHOULD ECMWF SOLUTION PAN OUT...A FEW STRONG THUNDERSTORMS WOULD BE POSSIBLE ON SATURDAY AS WELL. AFTER SYSTEM MOVES EASTWARD ON SUNDAY...DRY WEATHER WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES IS ON TAP FOR THE FIRST PART OF NEXT WEEK. && .AVIATION... MVFR CEILINGS AT KAEX...KLFT...AND KARA EARLY THIS MORNING WILL GIVE WAY TO SKC BY MID MORNING. VFR CONDITIONS WITH NORTH WINDS EXPECTED AT ALL TERMINALS THE REST OF THE DAY. && .MARINE... LEANED TOWARDS RUC GUIDANCE ON WINDS FOR TODAY AND WILL HAVE SMALL CRAFT ADVISORY CONTINUE FOR NEARSHORE WATERS THROUGH THIS MORNING AND OUTER WATERS INTO THE AFTERNOON. ALL AREAS SHOULD SEE WINDS FALL BELOW CRITERIA BY THIS EVENING. A GENERALLY CALM DAY IS ANTICIPATED TOMORROW BEFORE A ROUGH PERIOD FOR MARINE WEATHER BEGINS ON FRIDAY INTO THE WEEKEND...WITH WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED AND INCREASING WINDS AND SEAS. && .PRELIMINARY POINT TEMPS/POPS... KLCH 58 39 67 56 / 0 0 10 20 KBPT 61 41 68 57 / 0 0 10 20 KAEX 53 33 67 53 / 0 0 10 20 KLFT 53 37 67 55 / 0 0 10 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...SMALL CRAFT ADVISORY UNTIL 3 PM WEDNESDAY FOR THE FOLLOWING ZONES: WATERS FROM CAMERON, LA TO HIGH ISLAND, TX EXTENDING FROM 20 NM TO 60 NM...WATERS FROM INTRACOASTAL CITY, LA TO CAMERON, LA EXTENDING FROM 20 NM TO 60 NM...AND WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA EXTENDING FROM 20 NM TO 60 NM. SMALL CRAFT ADVISORY UNTIL NOON WEDNESDAY FOR THE FOLLOWING ZONES: COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON, LA OUT 20 NM...AND COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY, LA OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 9 AM WEDNESDAY FOR THE FOLLOWING ZONES: AND COASTAL WATERS FROM CAMERON, LA TO HIGH ISLAND, TX OUT 20 NM. && $$ SHAMBURGER la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC ISSUED BY NATIONAL WEATHER SERVICE BLACKSBURG VA 1042 AM EST WED FEB 13 2008 .SYNOPSIS... A WARM FRONT WILL LIFT SLOWLY NORTH THROUGH CENTRAL NORTH CAROLINA EARLY THIS AFTERNOON AHEAD OF A COLD FRONT MOVING ACROSS THE MOUNTAINS. THE FRONT AND THE ASSOCIATED STRONG UPPER TROUGH WILL MOVE EAST THROUGH THE REGION BY MID OR LAT AFTERNOON. HIGH PRESSURE WILL BUILD FROM THE TENNESSEE VALLEY ACROSS NORTH CAROLINA LATE TONIGHT THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1030 AM TODAY... MSAS SHOWS THE TENACIOUS WEDGE FROM LAST NIGHT SLOWLY STARTING TO GIVE WAY AS NOTED BY PRESSURE FALLS ACROSS THE WEDGE AREA AND SLIGHT BUMP IN TEMPS FROM SOUTH TO NORTH ACROSS THE TRIANGLE. HOWEVER WINDOW BETWEEN DEPARTING COLD POOL AND UPSTREAM COLD FRONT WONT LAST LONG AS WILL LIKELY TAKE THE FRONT TO FINALLY SCOUR OUT ALL THE LEFTOVER COLD AIR THIS AFTERNOON. WITH THE TROF AXIS STILL TO THE WEST...EXPECT BANDS OF -RA/SHRA TO PERSIST ACROSS THE WEST/NORTH INTO EARLY AFTERNOON BEFORE THE DRY SLOT WINS OUT AND THE FRONT TURNS THE FLOW MORE WESTERLY. THUS THINKING OF KEEPING HIGH POPS GOING FROM THE TRIAD EAST WHILE CUTTING BACK A BIT OVER THE SW. EVENTUALLY EXPECT WILL SEE THE DRY SLOT OVER THE EASTERN ZONES IN THE WAKE OF THE COASTAL WAVE FILL BACK IN WITH A BAND OF SHRA/ISOLD TSRA AS THE FRONT NEARS LATER ON. FORECAST INSTABILITY SUGGESTS THIS COVERAGE MAY REDEVELOP ACROSS THE SANDHILLS/CENTRAL COASTAL PLAIN BEFORE SLIDING TO THE COAST. OTRW CLOUDS TO HOLD WITH SOME BREAKS NW TIER AS DRIER W/NW TRAJECTORY DEVELOPS LATE WHICH SHOULD LIMIT SNOW THREAT UNLESS UPPER SYSTEMS SLOWS SOME. HIGH TEMPS VERY TRICKY GIVEN SLOWER WEDGE EXODUS AND LATER COLD ADVECTION ALOFT WEST WHILE WARMING CONTINUES SE OF THE WEDGE A BIT LONGER. BASED ON CURRENT TEMPS AND LATEST LAV...LOWERED HIGHS A CAT OR SO TRIANGLE NORTH AND WEST WHILE GOING CLOSE TO 70 SE. PREVIOUS DISCUSSION... AS OF 845 AM TODAY... WITH THE PASSAGE OF THE H85 WARM FRONT AND MID LEVEL DISTURBANCE (SEEN LIFTING UP THE NC COAST AT 830 AM...) THE HEAVIEST RAIN AND THREAT OF CONVECTION HAD SHIFTED NE OF CENTRAL NC. THE THREAT OF ISOLATED SEVERE STORMS HAD ALSO SHIFTED TO THE OUTER BANKS AS OF 845 AM. THERE WAS A DISTINCT DRY SLOT OVER CENTRAL NC THIS MORNING... WITH ADDITIONAL SHOWERS DEVELOPING OVER THE WESTERN PIEDMONT OF NC. THIS INCREASE IN SHOWERS TO OUR WEST SHOULD SPREAD EAST ACROSS CENTRAL NC MID TO LATE MORNING... AND CONTINUING THIS AFTERNOON AS THE STRONG UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE MOUNTAINS AND OVER THE PIEDMONT. THE ASSOCIATED SURFACE COLD FRONT WILL BE MOVING THROUGH CENTRAL NC DURING THE MID TO LATE AFTERNOON. HOWEVER... IT APPEARS THAT INSTABILITY WILL BE LIMITED. THE DEEPEST MOISTURE HAD ALREADY PULLED EAST WITH THE LEAD UPPER SYSTEM... THUS ONLY LIGHT QPF AMOUNTS OF 0.25 OR LESS IS EXPECTED THROUGH THE REMAINDER OF THIS EVENT. THE TEMPERATURES CONTINUED TO SHOW A WIDE RANGE AT MID MORNING... FROM 33-34 AT WINSTON-SALEM TO ROXBORO (IN THE HEART OF THE HYBRID COLD AIR DAMMING AREA)... TO THE LOWER 60S OVER AREAS FROM RALEIGH SOUTH AND EAST TO THE COAST (WHERE THE WARM FRONT HAD LIFTED NORTHWARD). THE HYBRID CAD EVENT IS EXPECTED TO GRADUALLY GIVE WAY THIS AFTERNOON AS THE COLD FRONT MOVES IN FROM THE WEST. HOWEVER... SURFACE HIGHS MAY STILL HOLD AROUND 50 IN THE NW... RANGING TO NEAR 70 SE. COLD AIR WILL BE ARRIVING AS THE REMAINDER OF THE SHOWERS ENDS LATE THIS AFTERNOON AND EARLY EVENING OVER THE NORTHERN PIEDMONT. THUS... THERE MAY BE A PERIOD OF LIGHT RAIN MIXED WITH A LITTLE LIGHT SNOW MAINLY ALONG THE NC/VA BORDER COUNTIES (N OF RDU) FOR A HOUR OR TWO BEFORE ENDING. HOWEVER... NO ACCUMULATION IS EXPECTED. PREVIOUS DISCUSSION... AS OF 220 AM WEDNESDAY... THE SYNOPTIC PATTERN IS EVOLVING LARGELY AS EXPECTED EARLY THIS MORNING... WITH THE FULL LATITUDE MID LEVEL TROUGH AMPLIFYING OVER THE MISS VALLEY THEN SHARPENING AS IT SWINGS THROUGH NC TONIGHT. SEVERAL WEAK LOWS EXIST ALONG THE COLD FRONT... CURRENTLY RUNNING FROM E OH TO E TN TO S MS... AND ANOTHER LEE LOW APPEARS TO BE FORMING ALONG THE WEDGE FRONT OVER UPSTATE SC INTO THE SRN NC FOOTHILLS. DESPITE PRECIPITATION FALLING THROUGH 10-15C AIR JUST 0.5-1.0 KM ALOFT... THE STABLE WEDGE REMAINS LOCKED IN OVER THE WESTERN PIEDMONT WHERE SURFACE TEMPS HOLD IN THE LOW-MID 30S. THE WEDGE FRONT HAS MOVED LITTLE IN THE LAST SEVERAL HOURS... STRETCHING FROM JUST SE OF WADESBORO / SANFORD / RALEIGH / HALIFAX. AS ONE MIGHT EXPECT... THE LARGE SCALE MODELS ARE DEPICTING THE DETAILS OF THE WEDGE REGIME POORLY. THE RUC13 IS DOING MUCH BETTER AND IT INDICATES THAT THE STABLE POOL WILL NOT BECOME DISLODGED FROM THE FAR NW PIEDMONT PRIOR TO COLD FRONT PASSAGE. 925-850 MB WINDS ARE FROM THE SOUTH... NEARLY PARALLEL TO THE WEDGE FRONT... AND ARE EXPECTED TO VEER TO WSW AS A LOW LEVEL TROUGH... LOCATED ALONG THE AL/GA BORDER AT 00Z... PIVOTS NORTHEAST AND THROUGH THE CWA LATER THIS MORNING. ALL OF THIS MEANS THAT TEMPERATURES IN THE TRIAD ARE ONLY EXPECTED TO RISE THROUGH THE 30S... AND THAT MAY BE OPTIMISTIC... BEFORE THE COLD FRONT PUSHES THROUGH TOWARD MIDDAY... AND THE POSSIBLE DEVELOPMENT OF THE LEE LOW ALONG THE WEDGE FRONT WOULD ONLY REINFORCE THIS IDEA. TEMPERATURES IN THE SOUTHEAST HOWEVER WILL UNDOUBTEDLY HOLD IN OR RISE THROUGH THE LOW-MID 60S AS INTENSE LOW LEVEL WARM AIR ADVECTION PERSISTS. REGARDING RAIN CHANCES AND THE RISK OF SEVERE STORMS... LATEST GUIDANCE AND TRENDS ARE ON PACE WITH THE FORECAST WITH WIDESPREAD RAIN... OCCASIONALLY MODERATE AS PRECIPITABLE WATER VALUES ARE OVER 200% OF NORMAL... LASTING THROUGH THE MORNING. DYNAMIC FORCING IS STRONG WITH MODEL WIND PROGS ON THE 1.5 PVU SURFACE DEPICTING IDEALLY JUXTAPOSED POLAR AND SUBTROPICAL JETS OVER NC THIS MORNING... HOWEVER THE CHANCES OF STRONG CONVECTION AND ISOLATED SEVERE STORMS TODAY ARE HIGHLY RELIANT ON THE DEGREE OF POTENTIAL INSTABILITY. 00Z REGIONAL SOUNDINGS AND LATEST RUC-ADJUSTED PLOTS FROM SPC SHOW JUST 100 J/KG OF CAPE OR LESS (AND THIS IS ELEVATED POTENTIAL INSTABILITY WEST OF THE WEDGE FRONT) ALTHOUGH ANY ADDITIONAL BOUNDARY LAYER WARMING WILL PUMP UP THESE NUMBERS QUICKLY IN THE WARM SECTOR... AND BUFR SOUNDINGS AT FAY SHOW A FEW HUNDRED J/KG OF CAPE BY THIS AFTERNOON. OF COURSE THE LOW LEVEL STORM RELATIVE HELICITY IS OVER 500 M2/S2 NEAR AND NW OF THE WEDGE FRONT... SO IF WE CAN GET ANY DISCRETE CONVECTIVE ELEMENTS GOING... THEY`LL NEED TO BE WATCHED FOR QUICK SPINUP IF THEY TRAVERSE THIS ZONE OF HIGH VORTICITY. WILL ALSO NEED TO WATCH NEAR A SURFACE LOW CENTER EXPECTED TO SPIN UP OFF THE SC COAST THIS MORNING... ASSOCIATED WITH A MID LEVEL VORTICITY MAX NOTED ON WATER VAPOR IMAGERY TRACKING UP THE COAST. LATER TODAY... AS THE 80+ KT 500 MB JET WRAPS AROUND THE MID LEVEL LOW UP INTO ERN NC... HODOGRAPHS WILL BECOME STRONGLY LINEAR WITH 60+ KTS OF DEEP LAYER SHEAR... AND A FEW BOWING SEGMENTS MAY PRODUCE DAMAGING WIND GUSTS... MAINLY ALONG/EAST OF I-95 THIS AFTERNOON WHERE SREF PROBABILITIES OF NEGATIVE LI VALUES AND CAPES OF 500-1000 J/KG ARE BETTER THAN 50%... AND WHERE A POOL OF 100-150 M MID LEVEL HEIGHT FALLS WILL MOVE IN LATE IN THE DAY. AFTER COLD FRONTAL PASSAGE BETWEEN 2 AND 8 PM... THE LOW LEVEL COLD AIR WILL SLOWLY FILTER INTO THE CWA WITH THE TERRAIN TEMPORARILY HOLDING OFF THE HIGH BUILDING IN FROM THE WEST. THERE IS SOME CONCERN ABOUT A POSSIBLE END AS A BRIEF PERIOD OF WINTRY PRECIP TONIGHT. THE EXTENT AND SPEED OF THE COLDER AIR PUSHING IN AND THE POTENTIAL RAPID DEEPENING OF A SURFACE LOW OVER OR JUST OFF THE NE NC COAST... AS THE DEEPENING MID LEVEL LOW SHIFTS OVER THE AREA... BOTH POSE SOME CONCERN. AT THIS TIME IT LOOKS LIKE THE COLD AIR WILL LARGELY BE CHASING THE BEST MOISTURE... AND FORECAST BUFR SOUNDINGS FROM BOTH THE NAM AND GFS INDICATE WANING MOISTURE IN THE CRYSTAL GROWTH AREA ALOFT. BUT GIVEN ENOUGH DYNAMIC LIFT PRODUCED BY THE MID LEVEL LOW... THERE IS SOME POTENTIAL FOR SATURATION IN THIS AREA. BASED ON THIS... AND ON THE OVERALL VIGOROUS AND HIGHLY ANOMALOUS NATURE OF THIS SYSTEM... WILL INCLUDE A SHORT PERIOD OF INCONSEQUENTIAL RAIN/SNOW MIX IN THE NORTH BEFORE PRECIP ENDS OVERNIGHT. LOWS 28-37 ACROSS THE CWA. -GIH && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... AS OF 250 AM WEDNESDAY... A CHILLY NORTH-SOUTH ORIENTED SURFACE HIGH BUILDS QUICKLY INTO AND OVER NC THURSDAY. IN THE WAKE OF THE DEPARTING MID LEVEL TROUGH... SHORTWAVE RIDGING AND STRONG SUBSIDENCE WITH A VERY DRY COLUMN WILL EQUATE TO CONSIDERABLE SUNSHINE. THE LOW LEVEL THERMAL PROFILE SUPPORTS HIGHS CLOSE TO NORMAL THURSDAY... 52-58. AS THE SURFACE HIGH SHIFTS OFFSHORE LATE THURSDAY AND RETURN FLOW COMMENCES... LOW LEVEL THICKNESSES BOUNCE UP AROUND 10-15 M ABOVE NORMAL... SUPPORTING HIGHS AROUND 61-66 WITH INCREASING HIGH CLOUDS THROUGH THE DAY. -GIH && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... OUR NEXT SIGNIFICANT STORM SYSTEM... NOW PUSHING THROUGH THE PACIFIC NW... DROPS INTO THE DESERT SOUTHWEST AND DEEPENS FRIDAY NIGHT. MEANWHILE... A NORTHERN STREAM COLD FRONT WILL DROP THROUGH THE AREA FRIDAY NIGHT. BUT WITH A PRECEDING DRY AND STABLE AIR MASS WITH DOWNSLOPE 850 MB FLOW... ALONG WITH A LACK OF SIGNIFICANT ISENTROPIC UPGLIDE OR OTHER LARGE SCALE FORCING MECHANISM... THIS FRONT SHOULD COME THROUGH LARGELY DRY BUT WITH CONSIDERABLE CLOUDINESS FRIDAY NIGHT. LOWS 34-40. LOW LEVEL THICKNESSES DROP BACK BELOW NORMAL BEHIND THE FRONT AND TEMPERATURES SHOULD FOLLOW SUIT... ONLY RISING TO 48-56 AS A POLAR SOURCE HIGH BUILDS IN FROM THE NORTH. EXPECT SKIES TO REMAIN MOSTLY CLOUDY FOR MUCH OF SATURDAY... PRIMARILY OVER SOUTHERN SECTIONS CLOSER TO THE FRONT... AS MID LEVEL MOISTURE ADVECTS ENE FROM THE SOUTHWEST LOW. THE GFS AND ECMWF CONTINUE TO PART WAYS WITH THE SPEED OF THIS STORM SYSTEM AS IT EJECTS THROUGH TX INTO THE OH VALLEY AND INTERIOR NE... ONLY NOW IT`S THE ECMWF THAT IS A TAD FASTER. BUT THEY DO SEEM TO BE CONVERGING ON A COMMON SOLUTION. THE CLOSED MID LEVEL LOW IS LIKELY TO RIDE NORTHEAST AND DAMPEN INTO A SHORTWAVE PASSING JUST TO OUR NW SUNDAY/SUNDAY NIGHT... AS THE LARGE SCALE PATTERN TRANSITIONS TO DEEP TROUGHING OVER ALL OF EASTERN NOAM. THE SURFACE HIGH CENTERED TO OUR NE IS EXPECTED TO NOSE BACK INTO THE PIEDMONT IN A DAMMING FASHION... AND AS RAIN CHANCES INCREASE SUNDAY WITH IMPROVING OVERRUNNING... A DAMMING REGIME IS LIKELY TO ENSUE. SURFACE CYCLOGENESIS IS LIKELY SOMEWHERE OVER THE WEST GULF COAST EARLY SUNDAY... AND WHILE THIS LOW IS LIKELY TO TRACK ALONG OR JUST EITHER SIDE OF THE APPALACHIANS ALONG A COLD FRONT... WHETHER IT ENDS UP AS A MILLER TYPE-A OR TYPE-B CYCLOGENESIS PATTERN IS STILL UP IN THE AIR. WILL HAVE INCREASING POPS FROM CHANCE SUNDAY TO LOW END LIKELY SUNDAY NIGHT INTO MONDAY. EXPECT BLUSTERY NW LOW LEVEL FLOW BEHIND THIS SYSTEM LATE MONDAY INTO TUESDAY WITH THE LARGE SCALE TROUGH AXIS PUSHING THROUGH... AND TEMPERATURES SHOULD BE WELL BELOW NORMAL. -GIH && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... AS OF 200 AM WEDNESDAY... SHARP CONTRAST IN TEMPERATURES ACROSS THE CWA DUE IMPART TO HIGH PRESSURE WEDGED OVER THE WESTERN PORTION OF THE CWA...COOLER AIR AND WARM/STATIONARY FRONT THROUGH THE EASTERN PORTION... WARMER AIR. AS A RESULT OF THIS WEATHER PATTERN... INT AND GSO WILL HAVE LIFR CONDITIONS THROUGH THE MORNING. WITH TEMPERATURES HOVERING AROUND FREEZING THERE IS A POSSIBILITY OF SOME FREEZING RAIN. RDU WILL SERVE AS THE TRANSITION ZONE WITH LIFR TO IFR CONDITIONS... WHILE FAY AND RWI... WHO WILL BE ALONG AND EAST OF THE FRONT WILL EXPERIENCE MVFR TO IFR CONDITIONS. THE SOUTHERLY FLOW ON THE EAST SIDE OF THE FRONT WILL ENHANCE THE CHANCE FOR RAIN OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA THROUGH THE MORNING. AS THE COLD FRONT THROUGH EASTERN TENNESSEE MOVES SLOWLY EAST... THE WEDGE SHOULD WEAKEN DURING THE LATE MORNING AS THE BOUNDARY THROUGH THE CENTRAL PORTION OF THE CWA MOVES WEST... SQUEEZING OUT THE WEDGE. AS THE COLD FRONT MOVES THROUGH THE CWA MAINLY DURING THE AFTERNOON... RAIN WILL OVERSPREAD THE AREA... BRINGING THE POSSIBILITY OF MVFR TO IFR CONDITIONS SHOWERS AND ISOLATED THUNDERSTORMS. CONDITIONS WILL IMPROVE TONIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM THE WEST... HOWEVER SOME RESIDUAL LOW LEVEL MOISTURE COULD LEAD TO SOME CLOUD BASES BETWEEN 25 HUNDRED AND 5 THOUSAND FEET THROUGH EARLY THURSDAY MORNING... OTHERWISE VFR CONDITIONS WILL PREVAIL THURSDAY THROUGH EARLY FRIDAY MORNING. HIGH PRESSURE OVER THE AREA WILL MOVE EAST AND SOUTHEAST OFFSHORE FRIDAY AFTERNOON AS A LOW OVER THE NORTHEAST UNITED STATES DRIFTS EAST AND SOUTHEAST. AS MOISTURE INCREASES OVER THE AREA WITH THE PASSAGE OF THE BOUNDARY THROUGH THE AREA... MVFR CEILINGS WILL BE POSSIBLE SATURDAY NIGHT. WIDESPREAD RAIN IS POSSIBLE SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT/JH NEAR TERM...JH/BADGETT SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...RHJ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1042 AM EST WED FEB 13 2008 .SYNOPSIS... A WARM FRONT WILL LIFT SLOWLY NORTH THROUGH CENTRAL NORTH CAROLINA EARLY THIS AFTERNOON AHEAD OF A COLD FRONT MOVING ACROSS THE MOUNTAINS. THE FRONT AND THE ASSOCIATED STRONG UPPER TROUGH WILL MOVE EAST THROUGH THE REGION BY MID OR LAT AFTERNOON. HIGH PRESSURE WILL BUILD FROM THE TENNESSEE VALLEY ACROSS NORTH CAROLINA LATE TONIGHT THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 1030 AM TODAY... MSAS SHOWS THE TENACIOUS WEDGE FROM LAST NIGHT SLOWLY STARTING TO GIVE WAY AS NOTED BY PRESSURE FALLS ACROSS THE WEDGE AREA AND SLIGHT BUMP IN TEMPS FROM SOUTH TO NORTH ACROSS THE TRIANGLE. HOWEVER WINDOW BETWEEN DEPARTING COLD POOL AND UPSTREAM COLD FRONT WONT LAST LONG AS WILL LIKELY TAKE THE FRONT TO FINALLY SCOUR OUT ALL THE LEFTOVER COLD AIR THIS AFTERNOON. WITH THE TROF AXIS STILL TO THE WEST...EXPECT BANDS OF -RA/SHRA TO PERSIST ACROSS THE WEST/NORTH INTO EARLY AFTERNOON BEFORE THE DRY SLOT WINS OUT AND THE FRONT TURNS THE FLOW MORE WESTERLY. THUS THINKING OF KEEPING HIGH POPS GOING FROM THE TRIAD EAST WHILE CUTTING BACK A BIT OVER THE SW. EVENTUALLY EXPECT WILL SEE THE DRY SLOT OVER THE EASTERN ZONES IN THE WAKE OF THE COASTAL WAVE FILL BACK IN WITH A BAND OF SHRA/ISOLD TSRA AS THE FRONT NEARS LATER ON. FORECAST INSTABILITY SUGGESTS THIS COVERAGE MAY REDEVELOP ACROSS THE SANDHILLS/CENTRAL COASTAL PLAIN BEFORE SLIDING TO THE COAST. OTRW CLOUDS TO HOLD WITH SOME BREAKS NW TIER AS DRIER W/NW TRAJECTORY DEVELOPS LATE WHICH SHOULD LIMIT SNOW THREAT UNLESS UPPER SYSTEMS SLOWS SOME. HIGH TEMPS VERY TRICKY GIVEN SLOWER WEDGE EXODUS AND LATER COLD ADVECTION ALOFT WEST WHILE WARMING CONTINUES SE OF THE WEDGE A BIT LONGER. BASED ON CURRENT TEMPS AND LATEST LAV...LOWERED HIGHS A CAT OR SO TRIANGLE NORTH AND WEST WHILE GOING CLOSE TO 70 SE. PREVIOUS DISCUSSION... AS OF 845 AM TODAY... WITH THE PASSAGE OF THE H85 WARM FRONT AND MID LEVEL DISTURBANCE (SEEN LIFTING UP THE NC COAST AT 830 AM...) THE HEAVIEST RAIN AND THREAT OF CONVECTION HAD SHIFTED NE OF CENTRAL NC. THE THREAT OF ISOLATED SEVERE STORMS HAD ALSO SHIFTED TO THE OUTER BANKS AS OF 845 AM. THERE WAS A DISTINCT DRY SLOT OVER CENTRAL NC THIS MORNING... WITH ADDITIONAL SHOWERS DEVELOPING OVER THE WESTERN PIEDMONT OF NC. THIS INCREASE IN SHOWERS TO OUR WEST SHOULD SPREAD EAST ACROSS CENTRAL NC MID TO LATE MORNING... AND CONTINUING THIS AFTERNOON AS THE STRONG UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE MOUNTAINS AND OVER THE PIEDMONT. THE ASSOCIATED SURFACE COLD FRONT WILL BE MOVING THROUGH CENTRAL NC DURING THE MID TO LATE AFTERNOON. HOWEVER... IT APPEARS THAT INSTABILITY WILL BE LIMITED. THE DEEPEST MOISTURE HAD ALREADY PULLED EAST WITH THE LEAD UPPER SYSTEM... THUS ONLY LIGHT QPF AMOUNTS OF 0.25 OR LESS IS EXPECTED THROUGH THE REMAINDER OF THIS EVENT. THE TEMPERATURES CONTINUED TO SHOW A WIDE RANGE AT MID MORNING... FROM 33-34 AT WINSTON-SALEM TO ROXBORO (IN THE HEART OF THE HYBRID COLD AIR DAMMING AREA)... TO THE LOWER 60S OVER AREAS FROM RALEIGH SOUTH AND EAST TO THE COAST (WHERE THE WARM FRONT HAD LIFTED NORTHWARD). THE HYBRID CAD EVENT IS EXPECTED TO GRADUALLY GIVE WAY THIS AFTERNOON AS THE COLD FRONT MOVES IN FROM THE WEST. HOWEVER... SURFACE HIGHS MAY STILL HOLD AROUND 50 IN THE NW... RANGING TO NEAR 70 SE. COLD AIR WILL BE ARRIVING AS THE REMAINDER OF THE SHOWERS ENDS LATE THIS AFTERNOON AND EARLY EVENING OVER THE NORTHERN PIEDMONT. THUS... THERE MAY BE A PERIOD OF LIGHT RAIN MIXED WITH A LITTLE LIGHT SNOW MAINLY ALONG THE NC/VA BORDER COUNTIES (N OF RDU) FOR A HOUR OR TWO BEFORE ENDING. HOWEVER... NO ACCUMULATION IS EXPECTED. PREVIOUS DISCUSSION... AS OF 220 AM WEDNESDAY... THE SYNOPTIC PATTERN IS EVOLVING LARGELY AS EXPECTED EARLY THIS MORNING... WITH THE FULL LATITUDE MID LEVEL TROUGH AMPLIFYING OVER THE MISS VALLEY THEN SHARPENING AS IT SWINGS THROUGH NC TONIGHT. SEVERAL WEAK LOWS EXIST ALONG THE COLD FRONT... CURRENTLY RUNNING FROM E OH TO E TN TO S MS... AND ANOTHER LEE LOW APPEARS TO BE FORMING ALONG THE WEDGE FRONT OVER UPSTATE SC INTO THE SRN NC FOOTHILLS. DESPITE PRECIPITATION FALLING THROUGH 10-15C AIR JUST 0.5-1.0 KM ALOFT... THE STABLE WEDGE REMAINS LOCKED IN OVER THE WESTERN PIEDMONT WHERE SURFACE TEMPS HOLD IN THE LOW-MID 30S. THE WEDGE FRONT HAS MOVED LITTLE IN THE LAST SEVERAL HOURS... STRETCHING FROM JUST SE OF WADESBORO / SANFORD / RALEIGH / HALIFAX. AS ONE MIGHT EXPECT... THE LARGE SCALE MODELS ARE DEPICTING THE DETAILS OF THE WEDGE REGIME POORLY. THE RUC13 IS DOING MUCH BETTER AND IT INDICATES THAT THE STABLE POOL WILL NOT BECOME DISLODGED FROM THE FAR NW PIEDMONT PRIOR TO COLD FRONT PASSAGE. 925-850 MB WINDS ARE FROM THE SOUTH... NEARLY PARALLEL TO THE WEDGE FRONT... AND ARE EXPECTED TO VEER TO WSW AS A LOW LEVEL TROUGH... LOCATED ALONG THE AL/GA BORDER AT 00Z... PIVOTS NORTHEAST AND THROUGH THE CWA LATER THIS MORNING. ALL OF THIS MEANS THAT TEMPERATURES IN THE TRIAD ARE ONLY EXPECTED TO RISE THROUGH THE 30S... AND THAT MAY BE OPTIMISTIC... BEFORE THE COLD FRONT PUSHES THROUGH TOWARD MIDDAY... AND THE POSSIBLE DEVELOPMENT OF THE LEE LOW ALONG THE WEDGE FRONT WOULD ONLY REINFORCE THIS IDEA. TEMPERATURES IN THE SOUTHEAST HOWEVER WILL UNDOUBTEDLY HOLD IN OR RISE THROUGH THE LOW-MID 60S AS INTENSE LOW LEVEL WARM AIR ADVECTION PERSISTS. REGARDING RAIN CHANCES AND THE RISK OF SEVERE STORMS... LATEST GUIDANCE AND TRENDS ARE ON PACE WITH THE FORECAST WITH WIDESPREAD RAIN... OCCASIONALLY MODERATE AS PRECIPITABLE WATER VALUES ARE OVER 200% OF NORMAL... LASTING THROUGH THE MORNING. DYNAMIC FORCING IS STRONG WITH MODEL WIND PROGS ON THE 1.5 PVU SURFACE DEPICTING IDEALLY JUXTAPOSED POLAR AND SUBTROPICAL JETS OVER NC THIS MORNING... HOWEVER THE CHANCES OF STRONG CONVECTION AND ISOLATED SEVERE STORMS TODAY ARE HIGHLY RELIANT ON THE DEGREE OF POTENTIAL INSTABILITY. 00Z REGIONAL SOUNDINGS AND LATEST RUC-ADJUSTED PLOTS FROM SPC SHOW JUST 100 J/KG OF CAPE OR LESS (AND THIS IS ELEVATED POTENTIAL INSTABILITY WEST OF THE WEDGE FRONT) ALTHOUGH ANY ADDITIONAL BOUNDARY LAYER WARMING WILL PUMP UP THESE NUMBERS QUICKLY IN THE WARM SECTOR... AND BUFR SOUNDINGS AT FAY SHOW A FEW HUNDRED J/KG OF CAPE BY THIS AFTERNOON. OF COURSE THE LOW LEVEL STORM RELATIVE HELICITY IS OVER 500 M2/S2 NEAR AND NW OF THE WEDGE FRONT... SO IF WE CAN GET ANY DISCRETE CONVECTIVE ELEMENTS GOING... THEY`LL NEED TO BE WATCHED FOR QUICK SPINUP IF THEY TRAVERSE THIS ZONE OF HIGH VORTICITY. WILL ALSO NEED TO WATCH NEAR A SURFACE LOW CENTER EXPECTED TO SPIN UP OFF THE SC COAST THIS MORNING... ASSOCIATED WITH A MID LEVEL VORTICITY MAX NOTED ON WATER VAPOR IMAGERY TRACKING UP THE COAST. LATER TODAY... AS THE 80+ KT 500 MB JET WRAPS AROUND THE MID LEVEL LOW UP INTO ERN NC... HODOGRAPHS WILL BECOME STRONGLY LINEAR WITH 60+ KTS OF DEEP LAYER SHEAR... AND A FEW BOWING SEGMENTS MAY PRODUCE DAMAGING WIND GUSTS... MAINLY ALONG/EAST OF I-95 THIS AFTERNOON WHERE SREF PROBABILITIES OF NEGATIVE LI VALUES AND CAPES OF 500-1000 J/KG ARE BETTER THAN 50%... AND WHERE A POOL OF 100-150 M MID LEVEL HEIGHT FALLS WILL MOVE IN LATE IN THE DAY. AFTER COLD FRONTAL PASSAGE BETWEEN 2 AND 8 PM... THE LOW LEVEL COLD AIR WILL SLOWLY FILTER INTO THE CWA WITH THE TERRAIN TEMPORARILY HOLDING OFF THE HIGH BUILDING IN FROM THE WEST. THERE IS SOME CONCERN ABOUT A POSSIBLE END AS A BRIEF PERIOD OF WINTRY PRECIP TONIGHT. THE EXTENT AND SPEED OF THE COLDER AIR PUSHING IN AND THE POTENTIAL RAPID DEEPENING OF A SURFACE LOW OVER OR JUST OFF THE NE NC COAST... AS THE DEEPENING MID LEVEL LOW SHIFTS OVER THE AREA... BOTH POSE SOME CONCERN. AT THIS TIME IT LOOKS LIKE THE COLD AIR WILL LARGELY BE CHASING THE BEST MOISTURE... AND FORECAST BUFR SOUNDINGS FROM BOTH THE NAM AND GFS INDICATE WANING MOISTURE IN THE CRYSTAL GROWTH AREA ALOFT. BUT GIVEN ENOUGH DYNAMIC LIFT PRODUCED BY THE MID LEVEL LOW... THERE IS SOME POTENTIAL FOR SATURATION IN THIS AREA. BASED ON THIS... AND ON THE OVERALL VIGOROUS AND HIGHLY ANOMALOUS NATURE OF THIS SYSTEM... WILL INCLUDE A SHORT PERIOD OF INCONSEQUENTIAL RAIN/SNOW MIX IN THE NORTH BEFORE PRECIP ENDS OVERNIGHT. LOWS 28-37 ACROSS THE CWA. -GIH && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... AS OF 250 AM WEDNESDAY... A CHILLY NORTH-SOUTH ORIENTED SURFACE HIGH BUILDS QUICKLY INTO AND OVER NC THURSDAY. IN THE WAKE OF THE DEPARTING MID LEVEL TROUGH... SHORTWAVE RIDGING AND STRONG SUBSIDENCE WITH A VERY DRY COLUMN WILL EQUATE TO CONSIDERABLE SUNSHINE. THE LOW LEVEL THERMAL PROFILE SUPPORTS HIGHS CLOSE TO NORMAL THURSDAY... 52-58. AS THE SURFACE HIGH SHIFTS OFFSHORE LATE THURSDAY AND RETURN FLOW COMMENCES... LOW LEVEL THICKNESSES BOUNCE UP AROUND 10-15 M ABOVE NORMAL... SUPPORTING HIGHS AROUND 61-66 WITH INCREASING HIGH CLOUDS THROUGH THE DAY. -GIH && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... AS OF 330 AM WEDNESDAY... OUR NEXT SIGNIFICANT STORM SYSTEM... NOW PUSHING THROUGH THE PACIFIC NW... DROPS INTO THE DESERT SOUTHWEST AND DEEPENS FRIDAY NIGHT. MEANWHILE... A NORTHERN STREAM COLD FRONT WILL DROP THROUGH THE AREA FRIDAY NIGHT. BUT WITH A PRECEDING DRY AND STABLE AIR MASS WITH DOWNSLOPE 850 MB FLOW... ALONG WITH A LACK OF SIGNIFICANT ISENTROPIC UPGLIDE OR OTHER LARGE SCALE FORCING MECHANISM... THIS FRONT SHOULD COME THROUGH LARGELY DRY BUT WITH CONSIDERABLE CLOUDINESS FRIDAY NIGHT. LOWS 34-40. LOW LEVEL THICKNESSES DROP BACK BELOW NORMAL BEHIND THE FRONT AND TEMPERATURES SHOULD FOLLOW SUIT... ONLY RISING TO 48-56 AS A POLAR SOURCE HIGH BUILDS IN FROM THE NORTH. EXPECT SKIES TO REMAIN MOSTLY CLOUDY FOR MUCH OF SATURDAY... PRIMARILY OVER SOUTHERN SECTIONS CLOSER TO THE FRONT... AS MID LEVEL MOISTURE ADVECTS ENE FROM THE SOUTHWEST LOW. THE GFS AND ECMWF CONTINUE TO PART WAYS WITH THE SPEED OF THIS STORM SYSTEM AS IT EJECTS THROUGH TX INTO THE OH VALLEY AND INTERIOR NE... ONLY NOW IT`S THE ECMWF THAT IS A TAD FASTER. BUT THEY DO SEEM TO BE CONVERGING ON A COMMON SOLUTION. THE CLOSED MID LEVEL LOW IS LIKELY TO RIDE NORTHEAST AND DAMPEN INTO A SHORTWAVE PASSING JUST TO OUR NW SUNDAY/SUNDAY NIGHT... AS THE LARGE SCALE PATTERN TRANSITIONS TO DEEP TROUGHING OVER ALL OF EASTERN NOAM. THE SURFACE HIGH CENTERED TO OUR NE IS EXPECTED TO NOSE BACK INTO THE PIEDMONT IN A DAMMING FASHION... AND AS RAIN CHANCES INCREASE SUNDAY WITH IMPROVING OVERRUNNING... A DAMMING REGIME IS LIKELY TO ENSUE. SURFACE CYCLOGENESIS IS LIKELY SOMEWHERE OVER THE WEST GULF COAST EARLY SUNDAY... AND WHILE THIS LOW IS LIKELY TO TRACK ALONG OR JUST EITHER SIDE OF THE APPALACHIANS ALONG A COLD FRONT... WHETHER IT ENDS UP AS A MILLER TYPE-A OR TYPE-B CYCLOGENESIS PATTERN IS STILL UP IN THE AIR. WILL HAVE INCREASING POPS FROM CHANCE SUNDAY TO LOW END LIKELY SUNDAY NIGHT INTO MONDAY. EXPECT BLUSTERY NW LOW LEVEL FLOW BEHIND THIS SYSTEM LATE MONDAY INTO TUESDAY WITH THE LARGE SCALE TROUGH AXIS PUSHING THROUGH... AND TEMPERATURES SHOULD BE WELL BELOW NORMAL. -GIH && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... AS OF 200 AM WEDNESDAY... SHARP CONTRAST IN TEMPERATURES ACROSS THE CWA DUE IMPART TO HIGH PRESSURE WEDGED OVER THE WESTERN PORTION OF THE CWA...COOLER AIR AND WARM/STATIONARY FRONT THROUGH THE EASTERN PORTION... WARMER AIR. AS A RESULT OF THIS WEATHER PATTERN... INT AND GSO WILL HAVE LIFR CONDITIONS THROUGH THE MORNING. WITH TEMPERATURES HOVERING AROUND FREEZING THERE IS A POSSIBILITY OF SOME FREEZING RAIN. RDU WILL SERVE AS THE TRANSITION ZONE WITH LIFR TO IFR CONDITIONS... WHILE FAY AND RWI... WHO WILL BE ALONG AND EAST OF THE FRONT WILL EXPERIENCE MVFR TO IFR CONDITIONS. THE SOUTHERLY FLOW ON THE EAST SIDE OF THE FRONT WILL ENHANCE THE CHANCE FOR RAIN OVER THE CENTRAL AND EASTERN PORTIONS OF THE CWA THROUGH THE MORNING. AS THE COLD FRONT THROUGH EASTERN TENNESSEE MOVES SLOWLY EAST... THE WEDGE SHOULD WEAKEN DURING THE LATE MORNING AS THE BOUNDARY THROUGH THE CENTRAL PORTION OF THE CWA MOVES WEST... SQUEEZING OUT THE WEDGE. AS THE COLD FRONT MOVES THROUGH THE CWA MAINLY DURING THE AFTERNOON... RAIN WILL OVERSPREAD THE AREA... BRINGING THE POSSIBILITY OF MVFR TO IFR CONDITIONS SHOWERS AND ISOLATED THUNDERSTORMS. CONDITIONS WILL IMPROVE TONIGHT AS HIGH PRESSURE BUILDS OVER THE AREA FROM THE WEST... HOWEVER SOME RESIDUAL LOW LEVEL MOISTURE COULD LEAD TO SOME CLOUD BASES BETWEEN 25 HUNDRED AND 5 THOUSAND FEET THROUGH EARLY THURSDAY MORNING... OTHERWISE VFR CONDITIONS WILL PREVAIL THURSDAY THROUGH EARLY FRIDAY MORNING. HIGH PRESSURE OVER THE AREA WILL MOVE EAST AND SOUTHEAST OFFSHORE FRIDAY AFTERNOON AS A LOW OVER THE NORTHEAST UNITED STATES DRIFTS EAST AND SOUTHEAST. AS MOISTURE INCREASES OVER THE AREA WITH THE PASSAGE OF THE BOUNDARY THROUGH THE AREA... MVFR CEILINGS WILL BE POSSIBLE SATURDAY NIGHT. WIDESPREAD RAIN IS POSSIBLE SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT/JH NEAR TERM...JH/BADGETT SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...RHJ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 505 PM EST WED FEB 13 2008 .SYNOPSIS... LOW PRESSURE WILL MOVE NE FROM CAPE COD THIS EVENING WHILE ANOTHER LOW DEVELOPING OFF MID ATLC COAST WILL TRACK WELL SE OF NANTUCKET THU MORNING. WEAK HIGH PRESSURE MOVES ACROSS THE REGION LATE THU AND THU EVENING. LOW PRESSURE MOVING THROUGH THE ST LAWRENCE VALLEY WILL SWING A COLD FRONT THROUGH NEW ENGLAND LATE FRI. MUCH COLDER AIR ON WILL FOLLOW FRI NIGHT THROUGH SAT NIGHT AS STRONG HIGH PRESSURE BUILDS INTO THE REGION. ANOTHER SIGNIFICANT LOW PRESSURE MAY BRING HEAVY RAIN SUN NIGHT AND MON WHICH MAY BEGIN AS A PERIOD OF SNOW AND ICE IN THE INTERIOR. COLDER UNSTABLE AIR MOVES IN FOR TUESDAY WITH WEAK HIGH PRESSURE ON WEDNESDAY. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... RECORD RAINS OCCURRED TODAY AT BDL AND BOSTON. EXPANDED WIND ADVY SE RI AND S COASTAL MA. RUNNING PRODUCTS. 45 KTS AT BID. SKYWARN IS HERE IN THE OFFICE. ICESTORM ..POCKEST IN THE MONADNOCKS. ZR ADVY IN MHT AREA FOR TAIL END ICING POSSIBLE THIS EVE. MAIN BRUNT OF THE SNOW AND ICE WAS DONE AT NOON. COMBINED SNOW AND ICE MADE NUMEROUS POWER OUTAGES NR I91-CT RVR VALLEY AND WE`VE HEARD OF ROOF FAILURES IN NH. SEE HYDRO SECTION...FLS`S/FFW ETC AS POSTED. FFA SHORTENED TO 9PM. BY THEN THE BAND OF R+ IS DONE AND URBAN FLOODING IS COMPLTED. THEN WE TURN TO RIVER FLOOD POTENTIAL AS WRITTEN IN THE FLOOD STATEMENT. A WIND ADVISORY CONTINUES FOR NANTUCKET AND CAPE COD TODAY. 40-45 KT GUSTS ARE POSSIBLE MAINLY LATE THIS AFTERNOON AHEAD OF THE DEVELOPING LOW. WE SAW G46KT AT MQE 1703Z WHILE BOS WAS CALM./ THATS ABOUT 650 FT OF HUGE WIND SHEAR IN THE VCNTY OF BOS AT 17Z. UNCONFIRMED REPORT OF WIND ADVY CRITERIA SE PYM COUNTY BUT ASOS MAXD AT 38KTS AN HOUR AFTER THE REPORT. AN ISOLATED THUNDERSTORM IS NOT OUT OF THE QUESTION ALONG THE SOUTH COAST AND ACROSS THE CAPE AND ISLANDS BETWEEN NOW AND 01Z TODAY. && .SHORT TERM /MIDNIGHT THROUGH 6 PM THURSDAY/... THU MORNING... CAN SEE A NEED OF A WXA FOR SE MA AND RI BTWN 09Z-14Z THU AS FRINGE BANDING OF THE VA CAPES LOW GRAZES SE NEW ENGL;AND WHILE STG BL CAA OCCURS. THIS COULD BE 0.1 WATER EQUIV MIXED PCPN COMBINED SLEET/SNOW AND WITH TEMPS FALLING WELL BLO FREEZING AT DAYBREAK /SEE NYS NOW FOR THE COLD SOURCE/. UK HAS IT WELL DEFINED AS DOES THE OP GFS AND ACTUALLY THE GFS ENS AND SREF ENS HINT AT THIS. THIS COULD MEAN A VERY SLOW MORNING COMMUTE VCNTY PVD-PYM-EWB. THU AFTN...TEMP FCST MAY BE 3F TOO WARM. BLO AVG CONFIDENCE ON THE CURRENT FCST TEMPS THU AFTN. THINK RUNNING IT 2-3F COLDER IS THE WAY TO MOVE ON THE ENXT FCST. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... SFC RIDGE QUICKLY MOVES EAST OF THE REGION THU NIGHT AS NEXT NORTHERN STREAM CLIPPER SYSTEM MOVES TO THE ST LAWRENCE VALLEY. ASSOCD COLD FRONT WILL SWING THROUGH THE REGION BY LATE FRI AND HAVE FOLLOWED FASTER CONSENSUS LED GFS SOLUTION. BEST MOISTURE AND UPPER LEVEL DYNAMICS WILL BE NORTH OF FA...BUT WE WILL KEEP SLIGHT CHC POPS IN THE GRIDS FOR FRI/FRI EVENING BASED ON STRENGTH OF FRONT. EXPECT GUSTY SW WINDS AHEAD OF THE FRONT ON FRI WHICH WILL PUSH TEMPS INTO UPPER 40S IN THE COASTAL PLAIN...BUT HOLDING IN THE UPPER 30S NW HIGHER TERRAIN. GUSTY POST FRONTAL NW WINDS WILL DRIVE MUCH COLDER AIR INTO SNE FRI NIGHT INTO SAT AS STRONG CAA DROPS 850 MB TEMPS TO NEAR -18. GFS 2M TEMPS VERY COLD LATE FRI NIGHT INTO SAT BUT PROBABLY ARE A LITTLE OVERDONE ON THIS AIRMASS. HOWEVER...GMOS TEMPS TOO WARM SO WE BLENDED GFS 2M TEMPS WITH GMOS FOR FRI NIGHT MIN AND SAT MAX. EXPECTED MINS LATE FRI NIGHT WILL RANGE FROM NEAR ZERO NW HIGHER TERRAIN TO TEENS S COAST WITH WIND CHILLS SAT MORNING POSSIBLY APPROACHING -15 FROM BERKSHIRES TO MONADNOCKS AND ZERO TO 5 COASTAL PLAIN. MAXES SAT WILL STRUGGLE INTO LOWER TEENS NW ZONES AND PROBABLY NOT MUCH HIGHER THAN LOW 20S COASTAL PLAIN. A PERIOD OF GOOD RADIATIONAL COOLING LIKELY SAT NIGHT AS HIGH BUILDS OVER THE REGION SO ANOTHER VERY COLD NIGHT EXPECTED SAT NIGHT. WE HAVE MINS RANGING FROM NEAR ZERO NW TO TEENS ALONG THE COAST...BUT TEMPS MAY END UP COLDER. MODELS ARE IN PRETTY GOOD AGREEMENT REGARDING NEXT STORM FOR SUN NGT/MON. PHASING OF NORTHERN AND SOUTHERN STREAM APPEARS LIKELY RESULTING IN HIGH AMPLITUDE TROF FROM GT LAKES TO GULF COAST ON MON. MODELS SHOW SOME DIFFERENCES WITH TRACK AND TIMING BUT ALL AGREE THAT LOW WILL TRACK TO THE WEST WHICH WILL RESULT IN MOST OF THE PRECIP FALLING AS RAIN SUN NGT INTO MON. HOWEVER...RESIDUAL COLD AIR MAY RESULT IN A PERIOD OF SNOW AND ICE AT THE ONSET IN THE DISTANT INTERIOR IF THE PRECIP COMES IN EARLY ENOUGH SUN NIGHT. EXPECT RISING TEMPS OVERNIGHT SUN NGT WITH WARM SECTOR 50S POSSIBLE ON MON IN THE COASTAL PLAIN. THIS STORM HAS POTENTIAL TO BE ANOTHER HEAVY RAFL PRODUCER. GEFS SHOWING STRONG SOUTHERLY INFLOW OF +3SD COMBINED WITH +4SD PWAT ANOMALY WHICH IS A STRONG SIGNAL FOR HEAVY RAIN. 1-2" RAFL WITH LOCALLY HIGHER AMOUNTS SEEMS MORE THAN REASONABLE FOR THIS EVENT AND CONFIDENCE IS ABOVE AVERAGE GIVEN GFS AND INTERNATIONAL MODELS HAVE AGREEMENT ON THIS. RAIN ENDS BY MON NIGHT...THEN COLDER TUE/WED WITH PTCLDY SKIES. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... TODAY...IFR/LIFR IN RAIN...OCCASIONALLY HEAVY...WITH ISOLATED THUNDER MAINLY SOUTH COAST AND CAPE COD. LLWS ACK/HYA/PVD/BOS WITH STRONG SOUTHERLY LOW LEVEL JET. WIND GUSTS TO 40 KT POSSIBLE AT KACK. ICE FREE WIND SENSOR PBLMS FORCED ADDING NIL AMD TO ORH. WE WILL AMD ORH AND ANY OTHER NIL AMDS AS TIME AND CONFIDENCE DICTATES. TONIGHT...CIGS/VSBY IMPROVE STEADILY TO GENERALLY VFR EXCPT IFR CIGS ACK REGION. THEN CONDS AT PVD HYA AND ACK MAY DETEIORATE FOR A FEW HOURS TO IFR OR LIFR IN MXD PCPN...POSSIBLY BRIEFLY HEAVY FOR AN HOUR OR SO AROUND SUNRISE AS CSI INDICATED IN SOME OF OUR GUIDANCE. THU...VFR NW AND BECOMING VFR SE. PLS SEE TAFS FOR DETAILS. OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... VFR THU NIGHT THROUGH SUN. LOW PROB OF BRIEF MVFR FRI AFTN AND FRI EVENING IF ANY RA/SNOW SHOWERS DEVELOP. GUSTY PREFRONTAL SW WINDS EXPECTED FRI FOLLOWED BY GUSTY NW WINDS FRI NIGHT. CONDITIONS LIKELY LOWERING TO IFR SUN NGT AND MON WITH HEAVY RAIN POSSIBLE POSSIBLY STARTING AS SNOW/ICE IN THE INTERIOR SUN NIGHT. && .MARINE... MARGINAL SLY GALE NOW VCNTY CAPE COD. GETTER CHANCE NLY GALE THU MORNING S AND E OF CAPE COD. ELSEWHERE SCA AT TIMES THRU THU. OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... DIMINISHING WINDS THU NIGHT...THEN INCREASING PRE FRONTAL SW FLOW FRI FOLLWED BY NEAR GALE FORCE POST FRONTAL NW FLOW FRI NIGHT AND AREAS OF FREEZING SPRAY. NW WINDS GRADUALLY DIMINISH SAT WITH GENERALLY LIGHT WINDS SAT NIGHT. SOUTHERLY GALES POSSIBLE SUN NGT AND MON AS NEXT STRONG LOW TRACKS TO THE WEST. GFS VERY STRONG WITH LLJ...BUT IT IS STILL EARLY ON THIS. && .HYDROLOGY... UPDATED 10 AM WED PLS SEE ON GOING STMTS AND WARNINGS FOR LATEST INFO. FLOOD WATCH REMAINS POSTED FROM NORTHERN CT AND RI INTO S CENTRAL AND EASTERN MA AND PART OF SW NH INTO THU MORNING. HEAVIEST RAINFALL WAS CENTERED OVER CT VALLEY REGION LATE THIS MORNING AND NAM/RUC HAVE A GOOD HANDLE ON IT. BOTH MODELS SHIFT THIS AXIS INTO RI AND EASTERN MA THIS AFTERNOON...WHERE WE WILL ALSO HAVE SOME RUNOFF CONTRIBUTION FROM SNOW MELT DUE TO TEMPERATURES WELL UP INTO 40S AND EVEN LOWER 50S. COLDER AIR IS EXPECTED TO REMAIN IN PLACE ACROSS INTERIOR WHICH WILL LIMIT SNOW MELT. RAINFALL TOTALS OF 1.5 TO 2.5 INCHES ARE EXPECTED BY EARLY TONIGHT. IN ADDITION TO SIGNIFICANT URBAN AND POOR DRAINAGE FLOODING...WE ARE ALSO CONCERNED ABOUT MINOR FLOODING ON SEVERAL SMALLER RIVERS IN PARTS OF RI AND EASTERN MA. BASED UPON COORDINATION WITH NERFC...WE ARE WATCHING THE FOLLOWING FORECAST POINTS WHICH MAY GO INTO MINOR FLOOD EITHER TONIGHT OR EARLY THU MORNING: ASSABET RIVER AT MAYNARD MA SUDBURY RIVER AT SAXONVILLE MA BLACKSTONE RIVER AT WOONSOCKET RI PAWTUXET RIVER AT CRANSTON RI IN ADDITION...MANY OTHER SMALLER RIVERS IN CENTRAL AND EASTERN MA ARE EXPECTED TO CREST ABOVE THEIR ACTION STAGES BUT BELOW FLOOD STAGE...PRIMARILY IN LOWER MERRIMACK AND SOUTHERN NEW ENGLAND BASINS. PLEASE REFER TO THE DAILY RIVER AND LAKE SUMMARY /RVDBOX OR FGUS51 KBOX/ FOR SPECIFIC FORECASTS WHICH WILL BE UPDATED BY MIDDAY. && .CLIMATE... DAILY RECORD PRECIPITATION FOR FEBRUARY 13TH BOSTON 1.65 1966 NEW RECORD POSSIBLE TODAY! PROVIDENCE 2.59 1966 HARTFORD 1.69 1966 NEW RECORD TODAY! WORCESTER 3.16 1900 FEBRUARY 12TH 2006 WE HAD RECORD SNOWFALL BDL 21.9 AND ALSO GREATEST EVER. BOS 17.5 ORH 16.9 PVD 9.4 && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MAZ002. FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR MAZ020>024. NH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR NHZ011- 015. FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR NHZ012. FREEZING RAIN ADVISORY UNTIL 8 PM EST THIS EVENING FOR NHZ012. RI...FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR RIZ001>007. WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR RIZ007. MARINE...GALE WARNING UNTIL 7 PM EST THIS EVENING FOR ANZ231-232-250. SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ233>237. SMALL CRAFT ADVISORY FROM 3 AM TO 1 PM EST THURSDAY FOR ANZ230. GALE WARNING UNTIL 10 AM EST THURSDAY FOR ANZ254-255. && $$ SYNOPSIS...KJC/DRAG NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...KJC AVIATION...KJC/DRAG MARINE...KJC/DRAG HYDROLOGY... CLIMATE... ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 413 PM EST WED FEB 13 2008 .SYNOPSIS... DUAL COASTAL LOW PRES CENTERS IN CENTRAL LONG ISLAND SOUND AND TRYING TO REFORM OFF THE VIRGINIA CAPES DURING MID AFTERNOON WILL EVENTUALLY PASS E OF CAPE COD THU MORNING. WEAK HIGH PRES MOVES ACROSS THE REGION LATE THURSDAY. LOW PRES MOVING THROUGH THE ST LAWRENCE VALLEY WILL SWING A COLD FRONT THROUGH NEW ENGLAND LATE FRIDAY. VERY COLD HIGH PRES WILL MOVE THROUGH THE NORTHEAST SATURDAY. STRONG LOW PRES MOVING INTO THE GREAT LAKES REGION LATE SUN AND THEN INTO ONTARIO CANADA MON WILL BRING A BIT OF ICE OR SNOW AT THE START AND THEN POTENTIALLY SUBSTANTIAL RAINS ON MON. COLD UNSTABLE AIR MOVES IN FOR TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... RECORD RAINS OCCURRED TODAY AT BDL AND PROBABLY BOSTON. SKYWARN IS HERE IN THE OFFICE. ICESTORM ..POCKEST IN THE MONADNOCKS. ZR ADVY IN MHT AREA FOR TAIL END ICING POSSIBLE THIS EVE. MAIN BRUNT OF THE SNOW AND ICE WAS DONE AT NOON. COMBINED SNOW AND ICE MADE NUMEROUS POWER OUTAGES NR I91-CT RVR VALLEY AND WE`VE HEARD OF ROOF FAILURES IN NH. SEE HYDRO SECTION...FLS`S/FFW ETC AS POSTED. FFA SHORTENED TO 9PM. BY THEN THE BAND OF R+ IS DONE AND URBAN FLOODING IS COMPLTED. THEN WE TURN TO RIVER FLOOD POTENTIAL AS WRITTEN IN THE FLOOD STATEMENT. A WIND ADVISORY CONTINUES FOR NANTUCKET AND CAPE COD TODAY. 40-45 KT GUSTS ARE POSSIBLE MAINLY LATE THIS AFTERNOON AHEAD OF THE DEVELOPING LOW. WE SAW G46KT AT MQE 1703Z WHILE BOS WAS CALM./ THATS ABOUT 650 FT OF HUGE WIND SHEAR IN THE VCNTY OF BOS AT 17Z. UNCONFIRMED REPORT OF WIND ADVY CRITERIA SE PYM COUNTY BUT ASOS MAXD AT 38KTS AN HOUR AFTER THE REPORT. AN ISOLATED THUNDERSTORM IS NOT OUT OF THE QUESTION ALONG THE SOUTH COAST AND ACROSS THE CAPE AND ISLANDS BETWEEN NOW AND 01Z TODAY. && .SHORT TERM /MIDNIGHT THROUGH 6 PM THURSDAY/... THU MORNING... CAN SEE A NEED OF A WXA FOR SE MA AND RI BTWN 09Z-14Z THU AS FRINGE BANDING OF THE VA CAPES LOW GRAZES SE NEW ENGL;AND WHILE STG BL CAA OCCURS. THIS COULD BE 0.1 WATER EQUIV MIXED PCPN COMBINED SLEET/SNOW AND WITH TEMPS FALLING WELL BLO FREEZING AT DAYBREAK /SEE NYS NOW FOR THE COLD SOURCE/. UK HAS IT WELL DEFINED AS DOES THE OP GFS AND ACTUALLY THE GFS ENS AND SREF ENS HINT AT THIS. THIS COULD MEAN A VERY SLOW MORNING COMMUTE VCNTY PVD-PYM-EWB. THU AFTN...TEMP FCST MAY BE 3F TOO WARM. BLO AVG CONFIDENCE ON THE CURRENT FCST TEMPS THU AFTN. THINK RUNNING IT 2-3F COLDER IS THE WAY TO MOVE ON THE ENXT FCST. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... SOME UNCERTAINTY THURSDAY MORNING AS THE OPERATIONAL GFS AND THE NAM INDICATE A TRAILING LOW OFF THE COAST WITH RAIN LINGERING IN THE COASTAL PLAIN WHILE THE GFS ENSEMBLE AND OTHER MODELS SHOW A WEAK WAVE FARTHER OFFSHORE. WE KEPT SOME LINGERING CHANCE OF RAIN THURSDAY MORNING FOR THE SOUTHEAST ZONES...AND ESPECIALLY FOR THE CAPE AND ISLANDS. HIGH PRESSURE THEN BUILDS IN DURING THE AFTERNOON BRINGING DRY WEATHER. THE UPPER FLOW REMAINS WEST TO SOUTHWEST SO NO DRASTIC COOL DOWN IS EXPECTED FOR THURSDAY. THE HIGH MOVES OFFSHORE BY FRIDAY MORNING WITH A CLIPPER LOW IN THE ST LAWRENCE VALLEY SWINGING A COLD FRONT THROUGH THE NORTHEAST. TIMING AMONGST THE MODELS IS SIMILAR WITH THE FRONT ON A BOSTON-NEW YORK AXIS IN THE EVENING. MOISTURE LOOKS LIMITED BUT WITH FAVORABLE UPPER DYNAMICS...SO WE WILL GO WITH CHANCE POPS. PTYPE WILL BE RAIN SHOWERS LEADING THE FRONT...AND SNOW SHOWERS IN THE COLDER AIR TRAILING THE FRONT. STRONG PRESSURE RISES BEHIND THE FRONT WILL AID IN BRINGING STRONG WINDS FRIDAY NIGHT...WHICH IN TURN WILL BRING MUCH COLDER AIR TO THE REGION. THIS COLDER AIR WILL ALSO BE SUPPORTED BY A CHANGE IN THE UPPER WINDS TO NORTHWEST ON SATURDAY. 850 MB TEMPS WILL DROP FROM AROUND 0C ON FRIDAY AFTERNOON TO AROUND -16C SATURDAY AFTERNOON. SO MAX TEMPS ON SATURDAY SHOULD BE IN THE 20S...EXCEPT TEENS IN SOUTHERN NH AND NORTHWEST MASS. TWO SYSTEMS COME AT US LATE SUNDAY AND SUNDAY NIGHT...ONE FROM THE GREAT LAKES AND ONE FROM THE GULF COAST. THE GULF SYSTEM LOOKS TO BE THE CONTROLLING SYSTEM...SPREADING PRECIP INTO NEW ENGLAND SUNDAY NIGHT THROUGH MONDAY. WITH CLOUDS MOVING IN BY EVENING AND NO SOURCE OF COLD AIR IN PLACE TO OUR NORTH...WE EXPECT TEMPERATURES TO DIP A LITTLE IN THE EVENING BUT THEN SLOWLY RISE OVERNIGHT. PTYPE MAY START AS SNOW OR FREEZING RAIN ESPECIALLY IN THE INTERIOR...BUT THE OVERALL TREND WILL BE TOWARD RAIN. BEHIND THE STORM WILL BE ANOTHER BURST OF COLD ADVECTION WITH 850 MB TEMPERATURES AROUND -20C AND A LINGERING COLD POOL/UPPER TROF COMBINATION THROUGH WEDNESDAY. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... TODAY...IFR/LIFR IN RAIN...OCCASIONALLY HEAVY...WITH ISOLATED THUNDER MAINLY SOUTH COAST AND CAPE COD. LLWS ACK/HYA/PVD/BOS WITH STRONG SOUTHERLY LOW LEVEL JET. WIND GUSTS TO 40 KT POSSIBLE AT KACK. ICE FREE WIND SENSOR PBLMS FORCED ADDING NIL AMD TO ORH. WE WILL AMD ORH AND ANY OTHER NIL AMDS AS TIME AND CONFIDENCE DICTATES. TONIGHT...CIGS/VSBY IMPROVE STEADILY TO GENERALLY VFR EXCPT IFR CIGS ACK REGION. THEN CONDS AT PVD HYA AND ACK MAY DETEIORATE FOR A FEW HOURS TO IFR OR LIFR IN MXD PCPN...POSSIBLY BRIEFLY HEAVY FOR AN HOUR OR SO AROUND SUNRISE AS CSI INDICATED IN SOME OF OUR GUIDANCE. THU...VFR NW AND BECOMING VFR SE. PLS SEE TAFS FOR DETAILS. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... LINGERING IFR ON THE CAPE AND ISLANDS THURSDAY MORNING...OTHERWISE VFR THURSDAY AND EARLY FRIDAY. MVFR OR IFR IN SCATTERED RAIN AND SNOW SHOWERS FRIDAY AFTERNOON AND NIGHT. COLD WINDS PICKING UP FROM THE NORTHWEST FRIDAY NIGHT AND SATURDAY. WINDS DIMINISH SATURDAY AFTERNOON WITH VFR THROUGH SUNDAY MIDDAY. LOWERING CIGS DURING SUNDAY AFTERNOON AND EVENING WITH MVFR/IFR IN SNOW AND RAIN SUNDAY NIGHT. && .MARINE... MARGINAL SLY GALE NOW VCNTY CAPE COD. GETTER CHANCE NLY GALE THU MORNING S AND E OF CAPE COD. ELSEWHERE SCA AT TIMES THRU THU. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... NORTHWEST WINDS NEAR GALE FORCE THURSDAY MORNING WITH DIMINISHING WIND AND SEAS LATER IN THE DAY AND AT NIGHT AS HIGH PRESSURE MOVES OVERHEAD. INCREASING SOUTHWEST FLOW FRIDAY AS A COLD FRONT APPROACHES. AFTER THE FRONT MOVES THROUGH...NORTHWEST WINDS WILL INCREASE TO NEAR GALE FORCE AGAIN FRIDAY NIGHT AND EARLY SATURDAY. WINDS AND SEAS WILL THEN SUBSIDE AGAIN DURING THE DAY SATURDAY. AREAS OF FREEZING SPRAY ARE POSSIBLE FRIDAY NIGHT AND SATURDAY. ANOTHER STORM FROM THE GULF OF MEXICO WILL BRING SMALL CRAFT ADVISORY WINDS AND SEAS SUNDAY NIGHT WITH GUSTS APPROACHING GALES ON THE OUTER WATERS. && .HYDROLOGY... UPDATED 10 AM WED PLS SEE ON GOING STMTS AND WARNINGS FOR LATEST INFO. FLOOD WATCH REMAINS POSTED FROM NORTHERN CT AND RI INTO S CENTRAL AND EASTERN MA AND PART OF SW NH INTO THU MORNING. HEAVIEST RAINFALL WAS CENTERED OVER CT VALLEY REGION LATE THIS MORNING AND NAM/RUC HAVE A GOOD HANDLE ON IT. BOTH MODELS SHIFT THIS AXIS INTO RI AND EASTERN MA THIS AFTERNOON...WHERE WE WILL ALSO HAVE SOME RUNOFF CONTRIBUTION FROM SNOW MELT DUE TO TEMPERATURES WELL UP INTO 40S AND EVEN LOWER 50S. COLDER AIR IS EXPECTED TO REMAIN IN PLACE ACROSS INTERIOR WHICH WILL LIMIT SNOW MELT. RAINFALL TOTALS OF 1.5 TO 2.5 INCHES ARE EXPECTED BY EARLY TONIGHT. IN ADDITION TO SIGNIFICANT URBAN AND POOR DRAINAGE FLOODING...WE ARE ALSO CONCERNED ABOUT MINOR FLOODING ON SEVERAL SMALLER RIVERS IN PARTS OF RI AND EASTERN MA. BASED UPON COORDINATION WITH NERFC...WE ARE WATCHING THE FOLLOWING FORECAST POINTS WHICH MAY GO INTO MINOR FLOOD EITHER TONIGHT OR EARLY THU MORNING: ASSABET RIVER AT MAYNARD MA SUDBURY RIVER AT SAXONVILLE MA BLACKSTONE RIVER AT WOONSOCKET RI PAWTUXET RIVER AT CRANSTON RI IN ADDITION...MANY OTHER SMALLER RIVERS IN CENTRAL AND EASTERN MA ARE EXPECTED TO CREST ABOVE THEIR ACTION STAGES BUT BELOW FLOOD STAGE...PRIMARILY IN LOWER MERRIMACK AND SOUTHERN NEW ENGLAND BASINS. PLEASE REFER TO THE DAILY RIVER AND LAKE SUMMARY /RVDBOX OR FGUS51 KBOX/ FOR SPECIFIC FORECASTS WHICH WILL BE UPDATED BY MIDDAY. && .CLIMATE... DAILY RECORD PRECIPITATION FOR FEBRUARY 13TH BOSTON 1.65 1966 NEW RECORD POSSIBLE TODAY! PROVIDENCE 2.59 1966 HARTFORD 1.69 1966 NEW RECORD TODAY! WORCESTER 3.16 1900 FEBRUARY 12TH 2006 WE HAD RECORD SNOWFALL BDL 21.9 AND ALSO GREATEST EVER. BOS 17.5 ORH 16.9 PVD 9.4 .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH THROUGH THURSDAY MORNING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MAZ002>004-008>012-026. FLOOD WATCH THROUGH THURSDAY MORNING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ022-024. NH...WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NHZ011- 015. FLOOD WATCH THROUGH THURSDAY MORNING FOR NHZ012. RI...FLOOD WATCH THROUGH THURSDAY MORNING FOR RIZ001>007. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ230>237-250. GALE WARNING FROM 1 PM THIS AFTERNOON TO 7 PM EST THIS EVENING FOR ANZ254-255. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR CTZ002>004. MA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MAZ002. FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR MAZ005>007-009- 011>021. WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR MAZ022>024. NH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR NHZ011- 015. FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR NHZ012. FREEZING RAIN ADVISORY UNTIL 8 PM EST THIS EVENING FOR NHZ012. RI...FLOOD WATCH UNTIL 9 PM EST THIS EVENING FOR RIZ001>007. MARINE...GALE WARNING UNTIL 7 PM EST THIS EVENING FOR ANZ231-232-250. SMALL CRAFT ADVISORY UNTIL 1 PM EST THURSDAY FOR ANZ233>237. SMALL CRAFT ADVISORY FROM 3 AM TO 1 PM EST THURSDAY FOR ANZ230. GALE WARNING UNTIL 10 AM EST THURSDAY FOR ANZ254-255. && $$ SYNOPSIS...KJC/DRAG NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...KJC AVIATION...KJC/DRAG MARINE...KJC/DRAG HYDROLOGY... CLIMATE... ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE POCATELLO ID 1001 AM MST WED FEB 13 2008 .DISCUSSION...SURFACE COLD FRONT IS MOVING SOUTHWARD THROUGH THE SNAKE RIVER VALLEY AT 1000 AM AND THE INITIAL BAND OF SNOW SHOWERS IS MOVING INTO THE EASTERN AND SOUTH CENTRAL HIGHLANDS. A SECOND BAND IS TAKING SHAPE NEAR DUBOIS AND NORHWEST WINDS ARE JUST BEGINNING TO SPILL OUT OF THE CENTRAL MOUNTAINS THROUGH BIRCH CREK AND BIG AND LITTLE LOST VALLEYS. NAM12 AND RUC13 PICK UP ON THIS TAKING IT THROUGH IDAHO FALLS 1100-1300 AM AND POCATELLO ROUGHLY 1300-1500 AM. NORTHERLY WINDS UPSLOPE INTO THE POCATELLO AREA BUT SNOW BAND SHOULD PUSH THROUGH IN A COUPLE OF HOURS WITH LIMITED SNOW ACCUMULATION. FOR UPDATES THIS MORNING HAVE TRIMMED BACK SNOW ACCUMULATION IN THE SNAKE VALLEY TO AN INCH OR LESS. HIGH TEMPERATURES TODAY HAVE ALREADY OCCURRED AND UNDER NORTHERLY FLOW THIS AFTERNOON TEMPERATURES NOW WILL EITHER HOLD STEADY OR COOL SLIGHTLY. RS && .PREV DISCUSSION... /ISSUED 240 AM MST WED FEB 13 2008/ SHORT TERM...TODAY THROUGH FRIDAY NIGHT. LATEST SATELLITE IMAGERY SHOWING INCOMING SHORT-WAVE DIGGING STRONGLY SE INTO THE IDAHO PANHANDLE EARLY THIS MORNING WITH WRN EXTENT OF TROUGH EXTENDING TO THE OREGON COAST WHERE DECENT SUBSIDENCE/DRYING WAS NOTED IN THE WATER VAPOR CHANNEL. NAM/GFS STILL AT MINOR ODDS WITH SPEED OF PASSING UPPER TROUGH TODAY ALTHOUGH THE 06Z NAM IS BEGINNING TO LOOK MORE LIKE THE GFS WITH EACH NEW RUN. GFS HAS BEEN CONSISTENT OVER THE LAST SEVERAL RUNS DRIVING THE UPPER TROUGH INTO THE REGION THIS MORNING WITH ATTENDING PRECIPITATION SPREADING ACROSS THE CNTRL MOUNTAINS EARLY THIS MORNING THEN INTO THE SNAKE PLAINS AND SE HIGHLANDS BY 18Z AS COLD FRONT DIVES THROUGH REGION. UPPER TROUGH SLOWS AND BEGINS TO CLOSE OFF OVER SE IDAHO FROM 18-00Z THIS AFTERNOON AND THEN PER GFS DIGS SOUTH INTO NRN UTAH BY 06Z. THE FACT THAT THE MODEL HAS BEEN WANTING TO CLOSE THE CIRCULATION OFF OVER IDAHO AND YET MAINTAIN PROGRESSION OF LOW SWEEPING INTO NRN UTAH HAS BEEN SOMEWHAT BOTHERSOME AS EXPECTATION WOULD SUPPORT SLOWER MOVEMENT OF LOW. NAM PAINTING SIMILAR PICTURE HOWEVER SO WILL FLOAT ALONG WITH MODELS AND CONTINUE TO MONITOR SITUATION FOR POTENTIAL EXTENSION OF HIGHER POPS OVER THE SE HIGHLANDS INTO THE EVENING HOURS WITH HIGHER SNOWFALL TOTALS AND POTENTIAL HIGHLIGHTS WHERE WE PRESENTLY HAVE SUB-WARNING LEVEL SNOWFALL TODAY AND A GENERAL DRYING TREND ACROSS THE ENTIRE FORECAST AREA TONIGHT. SECOND ITEM OF CONCERN WOULD BE THE POTENTIAL FOR A BRIEF CONVERGENCE EVENT THIS AFTERNOON BEHIND PASSING SURFACE FRONT TRANSITIONING INTO UPSLOPE FLOW ACROSS THE SE FOOTHILLS THIS AFTERNOON. THUS HAVE CONTINUED A LIKELY MENTION OF PRECIPITATION ACROSS THE ERN FOOTHILLS THROUGH THE AFTERNOON. WAVE SHOULD BE WELL SOUTH OF THE REGION BY THURSDAY AFTERNOON AS A DRY NORTH FLOW ENVELOPS THE AREA. FLOW SHOULD BE CONDUCIVE TO CLEARING SKIES WHICH SPELLS A VERY COLD MORNING FOR THURSDAY NIGHT. THUS HAVE MAINTAINED FORECAST DRY CONDITIONS AND COLDER TEMPERATURES FOR THURSDAY NIGHT. RIDGE WEAKENS AS NEXT UPSTREAM PAC WAVE TOPS WEST COAST RIDGE FRIDAY AFTERNOON DIVING SE INTO MONTANA FRIDAY NIGHT WITH LEADING EDGE OF WEAK PRECIPITATION EVENT SKIRTING NE DIVIDE AREA. THUS HAVE INTRODUCED A SLIGHT CHANCE MENTION OF PRECIPITATION FOR NE MOUNTAINS. HUSTON LONG TERM...SATURDAY THROUGH WEDNESDAY. BOTH GFS AND ECMWF DEVELOP A HIGH AMPLITUDE UPPER RIDGE OVER THE WRN US ON SUNDAY. AGREEMENT IS FAIRLY GOOD THRU MON...BUT THEN THE GFS DROPS A SMALL UPPER LOW INTO THE GREAT BASIN BY MON EVE. THE ECMWF KEEPS THE RIDGE INTACT. LOOKING AT THE GFS ENSEMBLE MEMBERS...THERE IS SOME DYSFUNCTION IN THE HOUSEHOLD. SOME MEMBERS TAKE THE SIDE OF THE ECMWF. WITH THIS MUCH UNCERTAINTY...WILL MAKE ONLY MINOR CHANGES TO THE EXTENDED. WILL RAISE TEMPS A LITTLE TO REFLECT THE WARMER EFFECTS OF THE RIDGE. BY THE END OF THE PERIOD...THE ECMWF AND GFS ARE TOTALLY OUT OF PHASE. HEDGES AVIATION...IFR CIGS/VIS OVER THE UPPER SNAKE RIVER PLAIN WILL CONTINUE UNTIL MID MORNING...BUT WILL BE CLEARED OUT WHEN THE COLD FRONT PASSES. SOME LIMITED CIG/VIS DUE TO SNOW WILL OCCUR WITH THE FRONT...AND CONTINUE INTO THE AFTN HRS. STRONG SW WINDS WILL ACCOMPANY THE FRONT LAT MORNING THRU AFTN...WITH IMPROVING CONDITIONS BY LATE AFTN. HEDGES && .PIH WATCHES/WARNINGS/ADVISORIES...NONE. && $$ id AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 247 PM MST WED FEB 13 2008 .DISCUSSION...FORECAST CONCERNS ARE THE TIMING OF THE COLD FRONT THROUGH THE REGION OVERNIGHT ALONG WITH THE ONSET...DURATION...AND AMOUNT OF SNOW EXPECTED ALONG AND BEHIND THE FRONT THROUGH THE MIDDLE OF THURSDAY. HAVE BASED THE TIMING OF THE COLD FRONT AND ASSOCIATED WINDS TONIGHT THROUGH THURSDAY MORNING ON THE RUC WITH A TRANSITION TO THE NAM THROUGH THE END OF THE WEEK. NAM AND GFS ARE IN DECENT AGREEMENT ON THE FRONT TIMING AND AREAS OF PRECIPITATION...AND EVEN THE PRECIPITATION AMOUNTS. THE GFS USUALLY HAS A CLEAR OVERABUNDANCE OF PRECIPITATION IN THE UPSLOPE DRIVEN SNOWFALL...HOWEVER THE EASTERLY COMPONENT OF THE NEAR SURFACE WINDS IN MINIMAL AND THE BULK OF THE UPPER DYNAMICS DIVE FURTHER SOUTH INTO THE SOUTHWEST U.S. THE ONLY UPPER SUPPORT IS THE WEAK SHORT WAVE TROUGH THAT LIFTS OUT ACROSS THE TRI-STATE REGION EARLY THURSDAY...EXITING THE REGION BY LATE AFTERNOON. FEEL THE BULK OF THE PRECIPITATION WILL HAPPEN BETWEEN 09Z AND 18Z...QUICKLY TAPERING OFF AFTER 18Z AS THE FRONT CONTINUES SOUTH AND THE UPPER SHORT WAVE MOVES EAST. THE MAIN UPPER LOW CENTER CONTINUES TO DIVE SOUTH INTO THE EXTREME SOUTHWEST U.S. THROUGH FRIDAY AFTERNOON AS THE TAIL END OF THE UPPER TROUGH OVER THE NORTHERN PLAINS PASSES OVER THE CENTRAL HIGH PLAINS. THE UPPER LOW CENTER IS NO LONGER COUPLED TO THE UPPER TROUGH SWINGING THROUGH THE NORTHERN PLAINS AND LANGUISHES OVER THE SOUTHWEST U.S. UNTIL THE NEXT UPPER TROUGH IN THE SERIES APPROACHES ON SATURDAY AND BEGINS TO MOVE THE LOW EAST OF THE ROCKIES AND ACROSS TEXAS EARLY SUNDAY. THE PATTERN CONTINUES TO AMPLIFY SUNDAY AND MONDAY WITH THE UPPER RIDGE MOVING FROM THE WEST COAST TO THE INTERMOUNTAIN REGION BY MONDAY WITH DRY CONDITIONS AND SEASONAL TEMPERATURES EXPECTED ACROSS THE TRI-STATE REGION. TUESDAY AND WEDNESDAY...WARM FRONT CONTINUES ITS SLOW PROGRESSION EAST AHEAD OF THE UPPER LEVEL RIDGE BUILDING OVER MUCH OF THE WESTERN U.S. GFS AND ECMWF ARE IN REMARKABLY GOOD AGREEMENT ON LOCATION AND TIMING OF THE FRONT AND RIDGE AND TEMPERATURES THROUGH THE PERIOD. CONSIDERING TIMING OF THESE FEATURES IS DEPENDENT ON THE THE TIMING OF THE EARLY WEEK LOW...IT IS HARD TO SAY FOR CERTAIN EXACTLY HOW MUCH AND HOW QUICKLY TEMPERATURES WILL WARM...BUT EXPECT ABOVE NORMAL TEMPERATURES FOR BOTH DAYS. && .AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH 09Z AHEAD OF A COLD FRONT THAT WILL SWEEP THROUGH THE TRI-STATE REGION OVERNIGHT. CONDITIONS WILL BECOME MVFR BY 12Z WITH AREAS OF IFR CONDITIONS IN LIGHT SNOW AND BLOWING SNOW THROUGH 18Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ LOCKHART/SFJ/JDK ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 343 PM CST WED FEB 13 2008 .DISCUSSION... DAYS 1-2... FORECAST CHALLENGE WILL BE TEMPERATURES AND THE CHANCE FOR WINTRY PRECIPITATION THROUGH THURSDAY. THE 12Z UA ANALYSIS SHOWED A STRONG UPPER LEVEL SHORTWAVE TROUGH OVER WASHINGTON AND NORTHERN OREGON. THE GREATEST HEIGHT FALLS ON THE ORDER OF 100-120 METERS WERE TO THE SOUTH OF THE WAVE OVER NEVADA...SUGGESTING THAT THIS WAVE WILL CONTINUE TO DIVE SOUTHWARD. AT THE SURFACE...A STRONG PRESSURE GRADIENT EXISTED OVER SOUTHWEST KANSAS THIS AFTERNOON. SOUTH WINDS AT MANY LOCATIONS FROM LIBERAL TO SCOTT CITY THROUGH DODGE CITY HAVE BEEN IN AND OUT OF ADVISORY CRITERIA THIS AFTERNOON. RUC 850 WIND FIELDS SHOW THE AXIS OF THE STRONGEST WINDS SHIFTING EAST WITH TIME THROUGH THE REST OF THE AFTERNOON. A WIND ADVISORY WAS ISSUED FOR POINTS EAST OF A LINE FROM LIBERAL THROUGH DODGE CITY AND NESS CITY TO LACROSSE...LARNED AND GREENSBURG. WILL KEEP THIS INTACT AND LET IT EXPIRE AT 6 PM. WILL ALSO LET THE RED FLAG WARNING RIDE UNTIL EXPIRATION TIME AT 01Z. WHILE A FEW LOCATIONS COULD DROP TO 15 PERCENT RELATIVE HUMIDITY THROUGH PEAK HEATING, DON`T THINK ANY SITES WILL BE DOWN LONG ENOUGH TO VERIFY THE WARNING. THERE HAVE BEEN SOME WILDFIRES SPRINGING UP OVER WESTERN OKLAHOMA INTO THE TEXAS PANHANDLE AND THAT COULD ALSO HAPPEN HERE BEFORE THE WINDS SUBSIDE. THE 12Z MODEL RUNS ARE SIMILAR TO PREVIOUS RUNS IN MOVING THE UPPER LOW INTO ARIZONA BY 00Z FRIDAY. THE MODELS STILL SHOW THE FRONTAL BOUNDARY THROUGH ALL BUT THE SOUTHEAST CORNER OF THE CWA BY 12Z THURSDAY. TEMPERATURES SHOULD REMAIN FAIRLY STEADY DURING THE DAY AS COLDER AIR FILTERS IN. THE GFS SHOWS A PERIOD OF LOW LEVEL UPWARD VERTICAL MOTION ALONG WITH A SHALLOW NEARLY SATURATED LAYER THROUGH THE MORNING AND EARLY AFTERNOON. THE GOING FORECAST FOR A SLIGHT CHANCE FOR FREEZING DRIZZLE OR FLURRIES STILL LOOKS REASONABLE AT THIS TIME. APPEARS THE BEST CHANCE FOR LIGHT SNOW WILL BE OVER NORTHERN AND WESTERN SECTIONS OF THE CWA WHERE DEEPER MOISTURE WILL BE BUT EVEN THIS DOES NOT LOOK TOO PROMISING GIVEN THE LACK OF AVAILABLE MOISTURE. SOUTHWEST KANSAS WILL COME UNDER THE RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET THURSDAY NIGHT BUT WITH QUESTIONABLE MOISTURE AVAILABILITY...WILL KEEP POPS IN THE CHANCE/SLIGHT CHANCE RANGE FOR NOW. ON FRIDAY...MID LEVEL RIDGING WILL BE IN PLACE OVER WESTERN KANSAS AS THE NORTHERN STREAM WAVE MOVES BY AND THE SOUTHWEST UPPER LOW SPINS OVER SOUTHERN ARIZONA. DON`T SEE MUCH CHANCE FOR PRECIP OVER SOUTHWEST KANSAS SO WILL LOWER POPS EVEN FURTHER. HIGH TEMPERATURES FROM MOS ON FRIDAY SHOW SOME WIDE VARIATION. MODEL SOUNDINGS SUGGEST THAT THE GOING HIGHS IN THE LOWER 30S LOOKS REASONABLE SO WILL LEAVE INTACT. DAYS 3-7... AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL BE IN PLACE OVER THE DESERT SOUTHWEST TO BEGIN THE PERIOD. NUMERICAL MODELS ARE IN GENERAL AGREEMENT INDICATING THIS SYSTEM PUSHING EAST INTO THE SOUTHERN PLAINS OF TEXAS BY SATURDAY NIGHT AND ON INTO THE LOWER MISSISSIPPI RIVER VALLEY REGION SUNDAY BEFORE EJECTING TO THE NORTHEAST. THE SYSTEM WILL THEN CONJOIN WITH AN UPPER LEVEL SHORTWAVE TROUGH OF LOW PRESSURE THAT WILL MOVE EAST ACROSS THE NORTHERN PLAINS OVER THE WEEKEND. THIS PARTICULAR SHORTWAVE WILL BRING ANOTHER IN A SERIES OF COLD FRONTS THROUGH WESTERN KANSAS SATURDAY NIGHT. AS FOR TEMPERATURES, LEE SIDE TROUGHING WILL RETURN BRIEFLY ON SATURDAY ALLOWING FOR SURFACE HIGHS TO REBOUND A BIT BEFORE THE NEXT COLD FRONT PUSHES THROUGH THE AREA SATURDAY NIGHT. FOR SATURDAY, TEMPERATURES AT H85 WILL BE IN THE MID SINGLE DIGITS(C) ACROSS MUCH OF THE CWA WITH UPPER SINGLE DIGITS(C) IN EXTREME SOUTHWESTERN COUNTIES. COLD AIR ADVECTION WILL TAKE HOLD ACROSS THE FORECAST AREA ON SUNDAY IN WAKE OF THE PASSING COLD FRONT. THE GFS AND ECMWF ARE IN FAIR AGREEMENT INDICATING TEMPERATURES AT H85 RANGING FROM NEAR TO JUST BELOW ZERO(C) ACROSS NORTHEAST PORTIONS OF THE CWA TO THE MID SINGLE DIGITS(C) IN EXTREME SOUTHWEST COUNTIES. THE UPPER LEVEL TROUGH OF LOW PRESSURE OVER THE GREAT LAKES REGION WILL BEGIN TO GRADUALLY SLIDE EAST AS THE UPPER LEVEL RIDGING IN THE WEST SLOWLY APPROACHES THE ROCKY MOUNTAIN REGION THROUGH THE END OF THE PERIOD. THIS WILL ALLOW FOR A SLIGHT AND GRADUAL WARMING TREND THROUGH WEDNESDAY. PLAN TO ADJUST TEMPERATURES SLIGHTLY THROUGHOUT MUCH OF THE PERIOD. WILL BUMP UP TEMPERATURES A BIT ON TUESDAY AND TUESDAY NIGHT WITH THE UPPER LEVEL RIDGING TAKING HOLD. .AVIATION... A LEE SIDE TROUGH OF LOW PRESSURE IN EASTERN COLORADO WILL STRENGTHEN THROUGH EARLY THIS EVENING RESULTING IN FAIRLY STRONG SOUTHWESTERLY WINDS RANGING FROM 20 TO 30 MPH WITH GUSTS UP TO 40 MPH AT DDC AND GCK. WIND SPEEDS WILL BEGIN TO SUBSIDE DURING THE OVERNIGHT HOURS BEFORE A COLD FRONT BEGINS TO PUSH INTO WESTERN KANSAS EARLY TOMORROW MORNING. OTHERWISE, EXPECT VFR CONDITIONS AT ALL TAF SITES THROUGH TOMORROW MORNING WITH HIGH CLOUDS INCREASING OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DDC 30 30 13 35 / 10 30 30 10 GCK 26 26 12 36 / 10 30 30 10 EHA 28 29 13 38 / 10 40 40 10 LBL 29 30 14 37 / 10 30 30 10 HYS 26 26 7 31 / 10 30 30 10 P28 36 36 15 33 / 0 30 30 10 && .DDC WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM CST /6 PM MST/ THIS EVENING FOR KSZ061>063-074>078-084>088. WIND ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR KSZ045-046-064- 065-077>080-086>088. && $$ FN02/32 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 445 PM EST WED FEB 13 2008 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM SRN SASK TO NRN CA. A VIGOROUS SHORTWAVE WAS MOVING EAST THROUGH ERN MT. AT THE SFC...A RIDGE OF ARCTIC HIGH PRES OVER CNTRL CANADA EXTENDED INTO NRN MN AND THE MS VALLEY WHILE DIFFUSE LOW PRES DEVELOPING OVER THE WRN PLAINS. WEAK ACYC NNW FLOW ALONG WITH 850 MB TEMPS NEAR -16C CONTINUED TO SUPPORT LIGHT LAKE EFFECT SNOW SHOWERS INTO THE KEWEENAW AND AREAS EAST OF MARQUETTE. .SHORT TERM...(TONIGHT INTO THURSDAY NIGHT) MAIN FCST CONCERNS ARE SNOW AMOUNTS TONIGHT INTO THU AND LES POTENTIAL LATE THU INTO THU NIGHT. THE NAM CONTINUE TO BE THE OUTLIER WITH THE DEEPER/NRLY LOW TRACK AND HIGHER QPF AMOUNTS. THE FCST LEANS TOWARD THE CANADIAN REGIONAL GEM WHICH REFLECTS A COMPROMISE WEIGHTED TOWARD THE PREFERRED GFS. GIVEN THE VIGOROUS APPEARANCE OF THE UPSTREAM SHORTWAVE...EXPECT THE HIGHER RESOLUTION MODELS DEPICTION MAY BE MORE REALISTIC. A PERIOD OF IMPRESSIVE DYNAMICS WITH STRONG DEEP LAYER QVECTOR CONV AND UPPER LEVEL DIV WILL SUPPORT STRONG UPWARD MOTION LATE TONIGHT INTO THU MORNING. STEEPER LAPSE RATES WITH EPV VALUES NEAR ZERO INDICATE THE POTENTIAL FOR BAND(S) OF HEAVY SNOW TO DEVELOP. GIVEN THE COLD AIRMASS OVER THE AREA A HIGHER SNOW/WATER RATIO SNOWFALL WOULD BE EXPECTED. WHILE MOISTURE WILL BE LIMITED MODEL QPF AMOUNTS FROM 0.20 TO 0.40 FROM NORTH TO SOUTH ALONG WITH SNOW/WATER RATIO OF AROUND 20/1...PER COBB BUFKIT ALGORITHM...WOULD GIVE SNOWFALL AMOUNTS IN THE 4 TO 8 INCH RANGE DURING THE PERIOD OF HEAVIEST SNOW FROM 06Z-18Z. THIS IS ALSO IN LINE WITH 2-3 G/KG AVBL IN THE 285K-295K LAYER. AS THE SHORTWAVE MOVES OFF THU AFTERNOON CYCLONIC NNE FLOW WILL BACK TO N THEN NW BRINGING A TRANSITION FROM COMBINED SYSTEM/LES TO PURE LES DURING THE EVENING. WITH SEVERAL INCHES OF ADDITIONAL OF LES EXPECTED...KEPT THE HEADLINES GOING LONGER OF KIWD VCNTY AND N CNTRL UPPER MI. THE LES COMBINED WITH THE 3-6 INCHES OF SYSTEM SNOW OVER THE FAR W TIPPED THE BALANCE TOWARD A WARNING FOR 10 INCHES/24 HOURS EVEN THOUGH THE SNOW WITH THE SYSTEM MAY FALL SHORT OF WARNING CRITERIA. THE LES INTO MARQUETTE COUNTY MAY BE BRIEFLY HEAVY IF A NE FLOW LES BAND MOVES THROUGH...PER LCL HIGH RES WRF...AND WILL NEED TO EVALUATE POTENTIAL UPGRADE TO LES HEADLINES OR WARNING ALTHOUGH WARNING AMOUNTS ARE NOT EXPECTED AT THIS TIME. OTHERWISE...SNOW WILL TAPER OFF BY LATE AFTERNOON OVER THE REST OF UPPER MI. $$ .LONG TERM... THE SHORTWAVE ROTATING THROUGH THE BASE OF THE LONGWAVE TROUGH OVER EASTERN CANADA WILL MOVE INTO THE FORECAST AREA. THE SURFACE LOW WILL MOVE INTO SOUTHERN QUEBEC WHILE A RIDGE MOVE INTO THE MINNESOTA. THE INTERACTION BETWEEN THESE TWO SYSTEM WILL BE RESPONSIBLE FOR COLD AIR ADVECTION. THEREFORE...THE 850MB TEMPERATURES IS EXPECTED TO LOWER TO -26C OVER THE WESTERN LAKE. THE FLOW ACROSS THE LAKE SHOULD PRODUCE LES IN THE FAVORED AREAS...HOWEVER...THE COLD DRY AIR WILL LIMIT ACCUMULATIONS AS THE FLAKES SHOULD BE RATHER FINE. THE LONGWAVE TROUGH AND THE SURFACE RIDGE WILL CONTINUE TO TRACK EAST ON FRIDAY. THE RIDGE WILL EDGE INTO THE UPPER MISSISSIPPI RIVER VALLEY. SURFACE WINDS WILL START TO TAPER OFF AND BACK WEST. LAKE-850MB DELTA-T`S WILL CONTINUE TO BE IN THE LOW 20S OVER THE LAKE. WITH MORE STABLE CONDITIONS APPROACHING THE AREA AND WINDS BACKING WEST...THE LES SHOULD CONTINUE TO TAPER OFF ACROSS THE AREA. THE SURFACE HIGH WILL MOVE INTO THE OHIO RIVER VALLEY AS THE RIDGE BLANKETS THE UPPER GREAT LAKES. THE SURFACE HIGH WILL RELOCATE OVER THE MID ATLANTIC STATES ON SATURDAY. WINDS WILL CONTINUE TO BE OUT OF THE SOUTHWEST OVER THE FORECAST AREA. ANOTHER LOW CENTER WILL DIVE SOUTHEAST OUT OF CENTRAL CANADA INTO MANITOBA. AN ACCOMPANYING COLD FRONT WILL SWEEP THROUGH THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY. COLD AIR AND ISENTROPIC ASCENT AHEAD OF THE COLD FRONT COULD GENERATE A SOME SNOW OVER THE WEST END OF THE FORECAST AREA. A SHORTWAVE WILL DIG INTO THE NORTHERN PLAINS SATURDAY NIGHT...WHILE ANOTHER WEAK SHORTWAVE SHIFT INTO WESTERN U.P. SURFACE LOW WILL MOVE FROM WESTERN ONTARIO TO NORTHEAST LAKE SUPERIOR. THE LOW WILL ESCORT A COLD FRONT THROUGH THE FORECAST AREA INTO LOWER MICHIGAN. AHEAD OF THE LOW WINDS WILL BE OUT OF THE SOUTHWEST DRAWING MOISTURE INTO THE THE UPPER GREAT LAKES REGION. WINDS WILL BACK NORTHWEST FOLLOWING THE FROPA. DEEP MOISTURE...INSTABILITY WITH THE FROPA...SHORTWAVE ENERGY...AND 850MB TEMPERATURES AROUND -5C ADDS UP TO FAIRLY GOOD CHANCE OF SNOW TO THE AREA. THE SECONDARY SHORTWAVE WILL SWEEP INTO THE CENTRAL U.P. ON SUNDAY. AS THE SURFACE LOW MOVES INTO EAST CENTRAL ONTARIO. THE SOUTHERN PORTION OF THE LOW WILL SPLIT OFF AND SHIFT INTO THE OHIO VALLEY. MOISTURE WRAPPING AROUND THE LOW WILL FEED SNOWS OVER THE EAST PART OF THE FORECAST AREA. THIS WILL KEEP SNOW GOING OVER THE AREA. A THERMAL TROUGH WILL START TO MOVE INTO CENTRAL LAKE SUPERIOR LEAVING THE LAKE-850MB DELTA-T AROUND 16C...ENOUGH TO SUPPORT LES MAINLY OVER THE KEWEENAW PENINSULA AND EASTERN OF MUNISING. WEST OF THE KEWEENAW PENINSULA THE FETCH WILL BE SHORTER AND LIKELY TO LESS APPRECIABLE LES. THE MID LEVEL TROUGH WILL DEVELOP INTO A LONGWAVE OVER THE UPPER GREAT LAKES REGION SUNDAY NIGHT. THIS WILL DEEPEN THE THERMAL TROUGH OVER WESTERN LAKE SUPERIOR. COLD AIR ADVECTION WILL BRING THE 850MB TEMPERATURE TO AROUND -21C OVER THE WESTERN LAKE BY MONDAY MORNING. MEANWHILE THE SURFACE LOW WILL SETTLE INTO SOUTHEAST ONTARIO CAUSING THE WINDS TO VEER A LITTLE NORTH OVER LAKE SUPERIOR. THUS LOOKING FOR AN INCREASE IN LES OVER THE THE WESTERN U.P. AND EAST OF MARQUETTE. THE LONGWAVE TROUGH WILL REMAIN OVER THE AREA MONDAY NIGHT AND SURFACE LOW OVER SOUTHEAST LOWER MICHIGAN. WINDS WILL BE OUT OF THE NORTH AND NORTHWEST FEEDING LAKE EFFECT SNOWS. HOWEVER...A LOW LEVEL JET OVER THE LAKE WILL MIX TO SURFACE CAUSING WINDS TO 25KNOTS WHICH EFFECTIVE SHORTENS THE FETCH TIME AND THE LES. THE LONGWAVE TROUGH WILL EDGE EASTWARD ON TUESDAY THROUGH WEDNESDAY. A SURFACE RIDGE WILL MOVE INTO THE UPPER GREAT LAKES BY TUESDAY NIGHT. THIS WILL CAUSE THE WINDS TO BACK TO THE SOUTHWEST AND DECREASING THE POTENTIAL FOR LES. MORE STABLE CONDITIONS SUPPORTS POTENTIAL FOR SUN. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... PERSISTENT NW FLOW LAKE EFFECT WILL KEEP IFR VSBY AND MVFR CIGS GOING AT KCMX TIL WINDS WEAKEN AND SHIFT N AND NE LATE THIS AFTERNOON AND EVENING. HIGHER MVFR CIGS ARE EXPECTED AT KSAW THIS AFTERNOON. SNOW WITH THE APPROACHING LOW PRESSURE SYSTEM WILL MOVE IN BTWN 06Z-09Z WITH CIGS/VSBY LOWERING TO IFR CONDITIONS BY 11Z WHICH WILL PERSIST THROUGH THE MORNING. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT NORTHEAST GALES TO DEVELOP OVER WESTERN LAKE SUPERIOR THURSDAY MORNING AS A TIGHT GRADIENT DEVELOPS BETWEEN A DEVELOPING LOW PRESSURE SYSTEM IN WISCONSIN AND HIGH PRES OVER CNTRL CANADA. GALES MAY NEED TO BE EXTENDED INTO CNTRL AND EAST LAKE SUPERIOR IF THE LOW DEEPENS IN LINE WITH THE TRENDS FROM THE HIGHER RESOLUTION MODELS. N WINDS OF 20-30 KT BY SUNDAY MAY APPROACH GALE FORCE AS A LOW PRESSURE SYSTEM INTENSIFIES OVER THE CNTRL AND EASTERN LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...SNOW ADVISORY FROM 4 AM TO 10 PM EST THURSDAY FOR MIZ006-007-085. SNOW ADVISORY FROM 1 AM TO 7 PM EST THURSDAY FOR MIZ001>004-084. HEAVY SNOW WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 7 PM EST /6 PM CST/ THURSDAY FOR MIZ010>013. HEAVY SNOW WARNING FROM 10 PM THIS EVENING TO MIDNIGHT CST THURSDAY NIGHT FOR MIZ009. SNOW ADVISORY FROM 1 AM TO 10 PM EST THURSDAY FOR MIZ005. HEAVY SNOW WARNING FROM 4 AM TO 7 PM EST THURSDAY FOR MIZ014. LAKE SUPERIOR...HEAVY FREEZING SPRAY WARNING FROM 7 AM TO 7 PM EST THURSDAY FOR LSZ265. HEAVY FREEZING SPRAY WARNING FROM 4 AM TO 7 PM EST THURSDAY FOR LSZ263-264. GALE WARNING FROM 7 AM TO 1 PM EST THURSDAY FOR LSZ263. && $$ SYNOPSIS/SHORT TERM..JLB LONG TERM...DLG AVIATION/MARINE...JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1251 PM EST WED FEB 13 2008 .SYNOPSIS... A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON, CHANGING MIXED PRECIPITATION OVER TO SNOW SHOWERS. ISOLATED HEAVY RAINFALL WILL BE POSSIBLE OVER NORTHEAST PENNSYLVANIA THROUGH THE AFTERNOON. THE NEXT STORM SYSTEM TO AFFECT OUR REGION WILL BE ON FRIDAY, WHEN AN ARCTIC FRONT MOVES IN DURING THE LATE AFTERNOON AND EARLY EVENING. && .NEAR TERM /THROUGH TONIGHT/... HAVE ALLOWED WINTER WX ADVISORIES TO EXPIRE OVR THE ENTIRE FA AT 11AM. A FEW SITES ACROSS THE POCONOS HOVER AROUND FRZG BUT CONTINUE TO WARM. ISOLD POCKETS OF FREEZING RAIN WILL RMN POSSIBLE FOR THE NEXT 2 HRS OR SO UNTIL TEMPS RISE ABV FREEZING. HAVE RECEIVED REPORTS OF OVR ONE QUARTER INCH OF ICE OVR THE FAR SRN COUNTIES WITH SOME OF THE WEBCAMS SHOWING ICING ON TREES. THE WORST APPEARS TO BE OVR ALTHO ROADS WILL LIKELY HAVE ICE ON THEM INTO EARLY AFTN. FURTHER NORTH...COOLER H8 TEMPS DROPPING INTO THE FINGER LAKES AT THIS TIME WITH KITH NOW SWITCHING OVR TO SNOW. RAIN/SNOW LINE APPEARS TO RUN FROM UTICA-CORTLAND-ELMIRA AS OF 16Z WITH A FEW FLURRIES MIXING IN AS FAR SOUTH AS BINGHAMTON. MOST OF THIS SNOW WILL BE FAIRLY LIGHT AS IT QUICKLY MVS SOUTH...WITH ACCUMS TOPPING OUT ARND AN INCH AT MOST LOCATIONS THIS AFTN. TOUGH CALL NOW ACROSS FAR SRN ZONES FOR THIS AFTN AS A RAPIDLY DEVELOPING SFC LOW IS HEADED UP THE DELMARVA PENINSULA ATTM. AN ENHANCED AREA OF PCPN IS OCCURRING OVR THE ERN SEABOARD WITH COOLING CLD TOPS ACROSS ERN PA AND ERN NY. SFC BOUNDARY EXTENDS NORTH FROM THE SFC LOW THRU NJ AND INTO CENTRAL CONNECTICUT. LATEST RUC GUIDANCE WUD INDICATE THAT MOST OF THE HEAVIER RAIN WILL FALL JUST TO THE EAST OF CWA AS LOW RIDES UP THIS BOUNDARY. SULLIVAN/PIKE COUNTIES CONTINUE TO BE ON THE EDGE OF THE HEAVIEST RAINFALL. GUT FEELING IS THAT HEAVIER PCPN WILL STAY EAST AND FEEL IT PRUDENT TO HANDLE ANY LOCALIZED FLOODING WITH ADVISORIES AT THIS POINT. RECENT CALLS TO SULLIVAN COUNTY INDICATE NO PROBLEMS WITH THE RAINFALL. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... WITH THE EXCEPTION OF SOME MINOR LAKE EFFECT OVER THE NORTH COUNTRY ON THE BACKSIDE OF CURRENT STORM, THE WEATHER WILL BE QUIET UNTIL FRIDAY. ON FRIDAY, AN ARCTIC FRONT WILL GATHER STEAM TO THE WEST WHILE WARMER AIR FLOWS INTO NY AND PA. BY AFTERNOON TEMPS WILL REACH NEAR 40 OVER THE WILKES-BARRE SCRANTON AREA, THE UPPER 30S OVER THE SOUTHERN TIER OF NY, AND THE MID 30S IN THE FINGER LAKES. ANY PRECIPITATION WITHIN THE WARM ADVECTION SHOULD FALL AS RAIN. THE COLD FRONT WILL RIP THROUGH LATE AFTERNOON AND EARLY EVENING. WHILE THE LATEST GFS DOES NOT SUGGEST A WIN DEX EVENT, WITH MUCH OF THE ENERGY BACK BEHIND THE ARCTIC FRONT, I AM GROWING MORE CONCERNED OF A "FLASH FREEZE" SCENARIO. WET ROADS WILL FREEZE VERY QUICKLY WITH THE RAPID TEMPERATURE CHANGEOVER. FUTURE SHIFTS WILL NEED TO CONSIDER THIS POSSIBILITY, AND WE WILL MAKE A BRIEF MENTION IN THE HWO AS A HEADS UP. && .LONG TERM /SATURDAY THROUGH TUESDAY/... PD STARTS OFF QUITE CHILLY AS LRG HIPRES OVR THE OH VLY NOSES INTO THE REGION. WITH VERY DRY AIR AND H8 TEMPOS NEAR -20C...TEMPS WILL BE WELL BLO NRML. SOME LGT SNOW PSBL SUN AS A LOW RACES NORTH OF THE GREAT LAKES AND DVLPS WAA OVER THE REGION. MAIN PLAYER FOR THE PD ARRIVES NEAR THE END AS THE OPERATIONAL GFS NOW SHOWS A DECENT CSTL LOW FNLY MVG EAST OF THE AREA. THIS TRACK WLD GIVE US A RARE ALL SNOW EVENT FOR MON INTO TUE. IN FACT...EVERY ONE OF THE ENSEMBLE MEMBERS CRNTLY KEEP THE LOW TO THE EAST. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... COLDER AIR FILTERING IN BEHIND A COLD FRONT MOVING ACROSS CNY AND NEPA THIS AFTERNOON WILL CONTINUE TO CHANGE ANY MIXED RAIN/FZRA AND SNOW OVER TO ALL SNOW PRETTY MUCH EVERYWHERE BY 20Z. SNOW WILL BE MDT-HVY AT TIMES FOR BRIEF PERIODS IN A BANDED PRECIP STRUCTURE. WDSPRD IFR CIGS/VSBYS AND POCKETS OF LIFR WILL BE REPLACED BY IMPROVMENTS TO LIGHTER SNOW SHOWERS AND MVFR THIS EVENING AS COASTAL LOW PRESSURE MOVES NORTHEAST TOWARD NEW ENGLAND. DRIER AIR AND CLEARING NOTED ON SATELLITE OVER THE GTLKS...BUT MODEL SOUNDINGS CONTINUE TO SHOW LLVL MOISTURE TRAPPING BENEATH INVERSION. ALWAYS BEST TO PLAY THE CLOUD CARD HERE...SO WILL GRDLY TRANSITION TO VFR-MVFR CIGS LATE TONIGHT AND THURSDAY MORNING OVER UPSTATE NY TERMINALS...WITH SCATTERED CLOUDS AT AVP. WINDS NORTHWEST GENERALLY 8-12 KTS. FOR THE THURSDAY AFTERNOON THROUGH MONDAY... VFR THROUGH FRIDAY MORNING...FOLLOWED BY MVFR/IFR IN RAIN AND SNOW SHOWERS FRIDAY AFTERNOON INTO SATURDAY. LINGERING MVFR IN LAKE SNOW SHOWERS FOR SYR-RME ON SATURDAY...OTHERWISE VFR UNDER HIGH PRESSURE. FLIGHT RESTRICTIONS AGAIN EXPECTED TO DEVELOP SUNDAY AFTERNOON AND MONDAY AS LOW PRESSURE MOVES FROM MIDWEST THROUGH NY STATE. MIXED PRECIP AGAIN LIKELY WITH MVFR/IFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ AVIATION...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1041 AM CST WED FEB 13 2008 .UPDATE...SMALL CHANGES TO THE AFTERNOON FORECAST. HIGH PRESSURE WAS STILL HANGING OVER SOUTHEAST OKLAHOMA...WHILE THE NEXT STORM SYSTEM WAS DROPPING SOUTHWARD THROUGH THE ROCKIES. GIVEN THE PLACEMENT OF THE UPPER STORM AND JET STRUCTURE...EXPECT GREATEST PRESSURE FALLS IN FAR NORTHERN COLORADO TODAY AS OPPOSED SOUTHEAST COLORADO...WHICH OCCURS ON SOME OF OUR WINDIER DAYS. THUS...WINDS MAY BE SLOW TO INCREASE UNTIL LATE AFTERNOON DURING PEAK MIXING. LIGHT WINDS AND A COLD START TO THE DAY WILL ALSO MAKE IT DIFFICULT TO REACH MID AND UPPER 60S. HAVE LOWERED TEMPERATURES ONE OR TWO DEGREES ACROSS THE BOARD...BUT LOWERED TEMPERATURES A LITTLE MORE SIGNIFICANTLY IN NORTHWEST OKLAHOMA BASED ON TRENDS IN THE RUC...NAM...AND OBSERVATIONS. DESPITE THE COOLER MAX TEMPS...HUMIDITY STILL EXPECTED TO MEET RED FLAG CRITERIA WHERE THE WARNING IS CURRENTLY IN EFFECT. WILL NOT MAKE CHANGES TO THE WARNING...ALTHOUGH EXPECTING CRITERIA TO BE MET ONLY FOR 2 TO 3 HOURS LATE IN THE DAY. && BURKE && .PREV DISCUSSION... /ISSUED 545 AM CST WED FEB 13 2008/ DISCUSSION... MANY ISSUES TO CONSIDER THIS MORNING...SO WE APOLOGIZE FOR THE LATE ISSUANCE. FOR TODAY AND EVEN FOR MUCH OF THURSDAY...THE MAIN ISSUE IS FIRE WEATHER. EXPECT THE WIND TO INCREASE STEADILY THROUGHOUT THE DAY TODAY AS THE SURFACE HIGH CURRENTLY OVER THE AREA CONTINUES TO BREAK DOWN WITH THE STRENGTHENING AND EXPANDING LEE ROCKIES SURFACE TROUGH TO OUR WEST. CURRENT MODEL DATA CONTINUE TO SUPPORT THE STRONGEST WINDS TODAY AND OVERALL THE MOST CRITICAL CONDITIONS FOR TODAY JUST GRAZING OUR WESTERN OKLAHOMA AND WESTERN NORTH TEXAS COUNTIES. EXPECT WINDS THAT ARE SUFFICIENT TO SUPPORT A RED FLAG WARNING TO EVENTUALLY WORK THEIR WAY FARTHER EAST BUT NOT UNTIL VERY LATE TODAY OR TONIGHT. THUS WE FEEL MOST CONFIDENT ABOUT THE RED FLAG WARNING THAT IS ALREADY IN AFFECT BEING SUPPORTED METEOROLOGICALLY ACROSS EXTREME NORTHWEST AND WEST CENTRAL OKLAHOMA WITH LESS CONFIDENCE AS FAR EAST AS LAWTON AND WICHITA FALLS. WE COULD CANCEL A PORTION OF THE RED FLAG WARNING FOR TODAY BUT FEEL THE MESSAGE WOULD BE CONFUSING AS FIRES SEEM TO DEVELOP FREQUENTLY AROUND LAWTON AND THE WICHITA MOUNTAINS ANYWAY. EXPECT THE WELL-ADVERTISED COLD FRONT TO REACH NORTHWEST OKLAHOMA EARLY THURSDAY AND PERHAPS A LITTLE SOONER GIVEN THAT COLD FRONTS OF SIMILAR CHARACTER BEHAVE MORE LIKE A DENSITY CURRENT AND LESS LIKE A TRADITIONAL AND WEAKER COLD FRONT. THUS WE PREFER THE FASTER MOTION OF THE GFS/ECMWF...BUT LIKE THE SPATIAL/TEMPORAL RESOLUTION AND TEMPERATURE GRADIENTS OF THE NAM. OUR GRIDS THROUGH THURSDAY REFLECT THESE PREFERENCES. STRONG DOWNSLOPING WINDS AND THE ASSOCIATED VERY WARM/DRY AIR SHOULD INFLUENCE THE SOUTHWESTERN CORNER OF THE FORECAST AREA BY MIDDAY THURSDAY. FRONTAL SPEED WILL BE A KEY FACTOR IN DETERMINING JUST HOW MUCH OF THE AREA WILL BE INFLUENCED. COORDINATION WITH SURROUNDING OFFICES SUGGESTS A LACK OF CONFIDENCE IN FRONTAL SPEED...AND SO IT WAS DIFFICULT TO ARRIVE AT MUCH CONSENSUS REGARDING THE FIRE WEATHER CONDITIONS FOR THURSDAY. FEEL THAT EVEN WITH A FASTER FRONTAL SPEED...SOUTHWESTERN SECTIONS OF THE FORECAST AREA INCLUDING WICHITA FALLS AND DUNCAN MAY EXPERIENCE CRITICAL FIRE WEATHER CONDITIONS FOR SEVERAL HOURS INCLUDING A SUBSTANTIAL WIND SHIFT AS THE FRONT PASSES THROUGH...AND SO A FIRE WEATHER WATCH HAS BEEN ISSUED FOR THESE AREAS. REGARDING WINTRY WEATHER...GIVEN THE RANGE OF UNCERTAINTY WE HAVE USED MORE OF A MODEL CONSENSUS FOR THE EXPECTED SENSIBLE WEATHER CONDITIONS BEGINNING THURSDAY NIGHT NEAR AND ABOVE THE SOUTHWARD ADVANCING COLD FRONT AND ALSO LATER IN THE WEEKEND WHEN AN UPPER LOW IS EXPECTED TO AFFECT THE AREA. THIS APPROACH MOSTLY NEGATES THE USE OF THE NAM SINCE IT IS MOSTLY AN OUTLIER. A COUPLE MEMBERS OF THE GFS ENSEMBLE SUITE PREFER A NAM-LIKE SOLUTION AS WELL SO ITS SOLUTION CAN NOT BE COMPLETELY DISCARDED. NEVERTHELESS...THERE IS MODEL CONSENSUS THAT THE STRONG COLD FRONT WILL STRENGTHEN OVER SOUTHERN SECTIONS OF THE FORECAST LATE THURSDAY AS IT ENCOUNTERS WARMER AIR TO THE SOUTH. EXPECT THERE TO BE A RIBBON OF HIGHER LEVEL MOISTURE THAT INTERSECTS THE COLD FRONT OVER SOUTH CENTRAL/ SOUTHEASTERN OKLAHOMA BEFORE GRADUALLY BECOMING INCORPORATED AND LIFTED WITHIN THE FRONTAL BAND. AVERAGE MODEL QPF FORECASTS THROUGH 12Z FRIDAY ARE LESS 0.15 INCHES. WE EXPECT SOME OF THIS AMOUNT TO FALL IN THE FORM OF FREEZING RAIN AND/OR SLEET BUT THE PRECIPITATION MAY BEGIN AS LIQUID BEFORE THE SUB-FREEZING AIR UNDERCUTS THE PRECIPITATION. DIFFICULT TO SAY WHAT PERCENTAGE MAY BE ICE BY FRIDAY MORNING. MODEL FORECAST SOUNDING ACROSS SOUTHEAST OKLAHOMA ALSO SUGGEST WEAK INSTABILITY BECOMING AVAILABLE SO WE CAN NOT RULE OUT A FEW THUNDERSTORMS WITH HIGHER ICE ACCUMULATION RATES NOT OUT OF THE QUESTION. NO WATCHES ARE PLANNED AT THIS TIME...GIVEN THE EXPECTED AMOUNTS. HOWEVER...WE WILL ISSUE A SPECIAL WEATHER STATEMENT SHORTLY. A POINT OF EMPHASIS WITH THIS FORECAST PACKAGE WHICH IS ONE OF THE REASONS FOR A LATE ISSUANCE THIS MORNING...WAS TO BETTER DISTINGUISH THE PRECIPITATION EVENT THAT WE EXPECT THURSDAY NIGHT AND EARLY FRIDAY FROM A SECONDARY PRECIPITATION EVENT THAT WE EXPECT SATURDAY NIGHT AND SUNDAY. THE DETAILS ARE STILL A LITTLE UNCERTAIN. HOWEVER THE MODEL CONSENSUS FROM THE 00Z CYCLE WHICH WAS ALSO THE CASE 24 HRS AGO...IS THAT THE FRONTAL PASSAGE THURSDAY NIGHT AND ITS SUBSEQUENT INITIAL INTERCEPTION OF HIGHER MOISTURE WILL RESULT IN ABOUT 12-18 HRS OF PRECIPITATION...STARTING AS RAIN BUT THEN CHANGING TO FREEZING RAIN AND SLEET MOSTLY WELL SOUTH OF INTERSTATE 44 BEFORE ENDING AROUND MIDDAY FRIDAY. A SMALLER BUT WEAKER ZONE OF LIFT MAY ALSO PRODUCE A NARROW BAND OF LIGHT SNOW ACROSS NORTHWEST OKLAHOMA WHERE AN ASSOCIATED DEFORMATION ZONE/SHORTWAVE TROUGH IS DEPICTED BY THE MODELS. MIDDAY FRIDAY THROUGH MIDDAY SATURDAY MAY BE QUIET AS THE MAJORITY OF THE MODEL GUIDANCE SUGGESTS A SLOW APPROACH OF AN UPPER LOW BEFORE IT EJECTS ACROSS TEXAS SATURDAY NIGHT AND SUNDAY. A FEW OF THE MODELS...INCLUDING THE NAM/OPERATIONAL GFS/AND 2 OR 3 GFS ENSEMBLE MEMBERS SUGGEST THE LOW WILL MOVE ACROSS ACROSS TEXAS ABOUT 24 HRS FASTER...SO THIS POSSIBILITY NEEDS TO BE CONSIDERED. THUS...OUR FORECAST IS SOMEWHAT OF A COMPROMISE OF THE TWO SOLUTIONS BEGINNING FRIDAY NIGHT. SO DESPITE THERE BEING SOME POSSIBILITY OF IT BECOMING COMPLETELY DRY FOR 24 HRS OR SO...WE CONTINUE TO MAINTAIN LOW POPS OVER THE SOUTHEAST HALF OF THE AREA THROUGHOUT JUST IN CASE. OUR APPROACH ALSO RESULTED IN RAISING POPS SLIGHTLY FOR SATURDAY NIGHT AND SUNDAY ALONG AND EAST OF INTERSTATE 44 WITH A MIXTURE OF RAIN AND SNOW REMAINING THE PRIMARY PRECIPITATION TYPES. THIS TREND IN RAISING POPS FOR THESE TIME PERIODS IS ALSO AN INDICATION OF POTENTIALLY HIGHER QPF AMOUNTS...AS ALL OF THE MODELS SUGGEST A INVERTED SURFACE TROUGH FORMING OVER EAST TEXAS AND NOSING ITS WAY INTO THE FORECAST AREA. THIS PATTERN COULD SUPPORT HEAVY PRECIPITATION WITH THE MODEL THERMODYNAMIC PROFILES TOO CLOSE TO THE FREEZING LINE TO SAY IF ANY PRECIPITATION WILL BE ALL RAIN OR ALL SNOW. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 58 44 59 21 / 0 0 0 30 HOBART OK 64 42 58 22 / 0 0 0 10 WICHITA FALLS TX 66 47 71 26 / 0 0 0 40 GAGE OK 62 34 43 17 / 0 10 10 30 PONCA CITY OK 56 38 51 20 / 0 0 0 10 DURANT OK 57 44 65 28 / 0 0 0 50 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...RED FLAG WARNING UNTIL 7 PM CST THIS EVENING FOR OKZ004-009-010- 014>016-021-022-033>038-044. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR OKZ039-044-045. TX...RED FLAG WARNING UNTIL 7 PM CST THIS EVENING FOR TXZ083>090. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR TXZ086>090. && $$ JAMES ok