Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 01/28/08

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED AVN
NWS LOS ANGELES/OXNARD CA
1000 AM PST SUN JAN 27 2008 UPDATE FOR SHORT TERM WITH NEW LONG TERM FORECAST... ...SEVERE WEATHER POSSIBLE TODAY...MAINLY THIS AFTERNOON...ALONG WITH THE THREAT FOR SOME FLOODING OF LOW LYING URBAN AREAS...SMALL RIVERS AND STEAMS... UPDATE... SIGNIFICANT RAINS FELL OVERNIGHT WITH WIDESPREAD AMOUNTS IN EXCESS OF AN INCH ALONG THE LOWER COASTAL SLOPES OF THE SOUTH FACING FOOTHILLS. IN THE MOUNTAINS...THERE WERE NUMEROUS REPORTS OF RAINFALL IN EXCESS OF 2 INCHES WITH LOCAL AMOUNTS OF 4 INCHES OR SLIGHTLY MORE. IN ADDITION...OVERNIGHT...FREEZING LEVELS ROSE TO 7000 TO 8000 FEET...WHICH INCREASED THE MELTING FROM RECENT SNOWS. THE COMBINATION OF WET SOILS...RECENT HEAVY RAINS...AND SNOW MELT IS PUTTING A LOT OF WATER INTO THE RUN OFF SYSTEM OF LOCAL WATERWAYS. ANY ADDITIONAL HEAVY RAINS WILL RESULT MOSTLY IN ADDITIONAL RAPID RUN OFF. WITH RAINFALL RATES OF 1.5 INCHES OR MORE POSSIBLE WITH THE THUNDERSTORMS EXPECTED TODAY...THE POTENTIAL FOR FLASH FLOODING WITH ANY THUNDERSTORM ACTIVITY IS MUCH HIGHER THAN NORMAL. THUS...THERE IS REAL CONCERN FOR FLOODING AND MUDFLOWS TODAY...EVEN OUTSIDE OF RECENT BURN AREAS. THE REST OF THE SHORT TERM DISCUSSION IS UNCHANGED... .SHORT TERM... UPPER LOW IS CURRENTLY SPINNING AT 31.50/130 WHICH ANNOYINGLY IS ABOUT 100 MILES WEST OF WHERE BOTH THE NAM AND AND THE GFS INITIALIZED IT. THE OTHER MAJOR FEATURE IS A DRY SLOT WRAPPED AROUND THE LOW. THIS DRY SLOT IS NOW MOVING INTO THE CENTRAL COAST AND WILL SLOWLY WORK ITS WAY EASTWARD. AHEAD OF THE DRY SLOT LOW LEVEL MOIST INFLOW IS KEEPING A STEADY RAIN GOING. LATER THIS MORNING THE RAIN WILL TRANSITION TO A MORE SHOWERY NATURE AS THE MOISTURE PLUME MOVES AWAY AND THE COLD CORE LOW MOVES OVER. WRF BUFR SOUNDING SHOW THAT THIS IS GOING TO BE AN INTERESTING DAY. AT 22Z KSBA SHOWS AN LI OF -4 WITH 818 CAPE AND A TRIGGER TEMP OF ONLY 54 WHICH IS AS CLOSE TO AUTO-CONVECTIVE AS IT GETS AROUND HERE. EXPECT THERE WILL BE A FEW SEVERE TSTMS. BUFR SOUNDING SHOWS THE POTENTIAL FOR ALL MANOR OF SEVERE WEATHER SVR WINDS...HAIL...AND WITH VERY NICE LOW LEVEL HELICITY TORNADOES AND WATERSPOUTS ARE NOT OUT OF THE QUESTIONS. THE SEVERE WEATHER IS MOST LIKELY FROM POINT CONCEPTION TO OXNARD AS THIS IS THE MOST LIKELY TRACK OF THE UPPER LOW. STORM TOTALS FOR THIS SYSTEM WILL RUN 2 TO 4 INCHES ALONG THE COASTS WITH 3 TO 5 INCHES ALONG THE SOUTH FACING SLOPES. FAVORED LOCATIONS IN THE MOUNTAINS COULD SEE ABOUT 7 INCHES OF RAIN WITH THIS EVENT. HOWEVER...DUE TO THE SHOWERY NATURE OF THIS SYSTEM RAINFALL AMOUNTS WILL BE VERY VARIABLE THROUGHOUT THE AREA. ANY THUNDERSTORM THAT FORMS TODAY WILL LIKELY PRODUCE HIGH INTENSITY RAINFALL WHICH COULD PRODUCE A FLASH FLOOD ANYWHERE...NOT JUST THE BURN AREAS. BECAUSE OF THE SOUTH FLOW SNOW LEVELS WILL START OUT AT OR ABOVE 7000 FEET IN FACT CURRENT ACARS SHOWS THE Z LVL AROUND 9000 FEET. AS THE COLD UPPER LOW APPROACHES THE SNOW LEVEL WILL FALL TO 5000 FEET IN THE AFTERNOON AND THEN TO 4000 FEET OVERNIGHT. THE MOST SNOW WILL FALL THIS AFTERNOON. 06Z WRF SHOWS THE WINDS WINDING UP AGAIN LATER THIS MORNING AND AS A RESULT THE WIND WARNINGS/ADVISORIES HAVE BEEN EXTENDED UNTIL 300 PM. .LONG TERM... NEW MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT THROUGH NEXT WEEK. ALL MODELS AGREE THAT TODAYS STORM SYSTEM WILL MOVE RAPIDLY TO THE EAST AND THROUGH THE REGION TODAY. THIS WILL BE FOLLOWED BY A SERIES OF INSIDE SLIDERS THAT WILL PASS JUST NORTH OF THE REGION THROUGH THE REMAINDER OF THE SEVEN DAY FORECAST PERIOD. THE FIRST INSIDE SLIDER WILL FOLLOW DIRECTLY ON THE HEALS OF TODAYS DEPARTING STORM. THIS WILL BE A DRIER TYPE OF FRONTAL PASSAGE THAT WILL PROBABLY GIVE US A CHANCE FOR SOME SHOWERS ON MONDAY...BUT WILL PROBABLY NOT BE OF MUCH CONSEQUENCE COMPARED TO TODAYS EVENT. MODELS THEN HAVE A PERIOD OF MAINLY ZONAL FLOW EARLY TUESDAY...FOLLOWED BY YET ANOTHER INSIDE SLIDER LATE TUESDAY AND WEDNESDAY. THIS WILL PRESENT A CHANCE FOR SHOWERS...MAINLY TO THE CENTRAL COAST. LATE WEDNESDAY AND THURSDAY ALL THE MODELS HAVE WEAK RIDGING OVER THE REGION...SO IT SHOULD BE THE DRIEST DAY OF THE WEEK. THEN THE MODELS CALL FOR TWO MORE INSIDE SLIDERS...THE FIRST ON FRIDAY AND YET ANOTHER LATE SATURDAY INTO SUNDAY. THE BOTTOM LINE IS THAT THE OUTLOOK PERIOD WILL BE UNSETTLED WITH A NUMBER OF CHANCES FOR LIGHT RAIN AND SHOWERS...BUT NONE OF THESE SYSTEMS SHOULD BE AS POWERFUL AND DURABLE AS THE STORM THAT HAS BEEN IMPACTING THE REGION FOR MOST OF THE LAST WEEK. && .AVIATION...AT 1800Z...OR 1000 PST...SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST THROUGH THE AFTERNOON WHILE THE TROUGH CENTERED OVER THE BIGHT CONTINUES TO SHIFT EAST. SOUTHEAST WINDS 10G20KT WILL PERSIST OVER KLAX AND KBUR THROUGH EARLY EVENING THEN SHIFT TO SOUTHWEST THEN WEST AFTER MIDNIGHT AS THE TROUGH MOVES INLAND. $$ .LOX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING (SEE LAXWSWLOX). HIGH WIND WARNING (SEE LAXNPWLOX). FLOOD WATCH (SEE LAXFFALOX). WIND ADVISORY (SEE LAXNPWLOX). GALE WARNING (SEE LAXCWFLOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && $$ PUBLIC...RORKE/DANIELSON AVIATION...30 WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
900 AM PST SUN JAN 27 2008 UPDATE FOR SHORT TERM WITH NEW LONG TERM FORECAST... ...SEVERE WEATHER POSSIBLE TODAY...MAINLY THIS AFTERNOON...ALONG WITH THE THREAT FOR SOME FLOODING OF LOW LYING URBAN AREAS...SMALL RIVERS AND STEAMS... UPDATE... SIGNIFICANT RAINS FELL OVERNIGHT WITH WIDESPREAD AMOUNTS IN EXCESS OF AN INCH ALONG THE LOWER COASTAL SLOPES OF THE SOUTH FACING FOOTHILLS. IN THE MOUNTAINS...THERE WERE NUMEROUS REPORTS OF RAINFALL IN EXCESS OF 2 INCHES WITH LOCAL AMOUNTS OF 4 INCHES OR SLIGHTLY MORE. IN ADDITION...OVERNIGHT...FREEZING LEVELS ROSE TO 7000 TO 8000 FEET...WHICH INCREASED THE MELTING FROM RECENT SNOWS. THE COMBINATION OF WET SOILS...RECENT HEAVY RAINS...AND SNOW MELT IS PUTTING A LOT OF WATER INTO THE RUN OFF SYSTEM OF LOCAL WATERWAYS. ANY ADDITIONAL HEAVY RAINS WILL RESULT MOSTLY IN ADDITIONAL RAPID RUN OFF. WITH RAINFALL RATES OF 1.5 INCHES OR MORE POSSIBLE WITH THE THUNDERSTORMS EXPECTED TODAY...THE POTENTIAL FOR FLASH FLOODING WITH ANY THUNDERSTORM ACTIVITY IS MUCH HIGHER THAN NORMAL. THUS...THERE IS REAL CONCERN FOR FLOODING AND MUDFLOWS TODAY...EVEN OUTSIDE OF RECENT BURN AREAS. THE REST OF THE SHORT TERM DISCUSSION IS UNCHANGED... .SHORT TERM... UPPER LOW IS CURRENTLY SPINNING AT 31.50/130 WHICH ANNOYINGLY IS ABOUT 100 MILES WEST OF WHERE BOTH THE NAM AND AND THE GFS INITIALIZED IT. THE OTHER MAJOR FEATURE IS A DRY SLOT WRAPPED AROUND THE LOW. THIS DRY SLOT IS NOW MOVING INTO THE CENTRAL COAST AND WILL SLOWLY WORK ITS WAY EASTWARD. AHEAD OF THE DRY SLOT LOW LEVEL MOIST INFLOW IS KEEPING A STEADY RAIN GOING. LATER THIS MORNING THE RAIN WILL TRANSITION TO A MORE SHOWERY NATURE AS THE MOISTURE PLUME MOVES AWAY AND THE COLD CORE LOW MOVES OVER. WRF BUFR SOUNDING SHOW THAT THIS IS GOING TO BE AN INTERESTING DAY. AT 22Z KSBA SHOWS AN LI OF -4 WITH 818 CAPE AND A TRIGGER TEMP OF ONLY 54 WHICH IS AS CLOSE TO AUTO-CONVECTIVE AS IT GETS AROUND HERE. EXPECT THERE WILL BE A FEW SEVERE TSTMS. BUFR SOUNDING SHOWS THE POTENTIAL FOR ALL MANOR OF SEVERE WEATHER SVR WINDS...HAIL...AND WITH VERY NICE LOW LEVEL HELICITY TORNADOES AND WATERSPOUTS ARE NOT OUT OF THE QUESTIONS. THE SEVERE WEATHER IS MOST LIKELY FROM POINT CONCEPTION TO OXNARD AS THIS IS THE MOST LIKELY TRACK OF THE UPPER LOW. STORM TOTALS FOR THIS SYSTEM WILL RUN 2 TO 4 INCHES ALONG THE COASTS WITH 3 TO 5 INCHES ALONG THE SOUTH FACING SLOPES. FAVORED LOCATIONS IN THE MOUNTAINS COULD SEE ABOUT 7 INCHES OF RAIN WITH THIS EVENT. HOWEVER...DUE TO THE SHOWERY NATURE OF THIS SYSTEM RAINFALL AMOUNTS WILL BE VERY VARIABLE THROUGHOUT THE AREA. ANY THUNDERSTORM THAT FORMS TODAY WILL LIKELY PRODUCE HIGH INTENSITY RAINFALL WHICH COULD PRODUCE A FLASH FLOOD ANYWHERE...NOT JUST THE BURN AREAS. BECAUSE OF THE SOUTH FLOW SNOW LEVELS WILL START OUT AT OR ABOVE 7000 FEET IN FACT CURRENT ACARS SHOWS THE Z LVL AROUND 9000 FEET. AS THE COLD UPPER LOW APPROACHES THE SNOW LEVEL WILL FALL TO 5000 FEET IN THE AFTERNOON AND THEN TO 4000 FEET OVERNIGHT. THE MOST SNOW WILL FALL THIS AFTERNOON. 06Z WRF SHOWS THE WINDS WINDING UP AGAIN LATER THIS MORNING AND AS A RESULT THE WIND WARNINGS/ADVISORIES HAVE BEEN EXTENDED UNTIL 300 PM. .LONG TERM... NEW MEDIUM RANGE MODELS IN PRETTY GOOD AGREEMENT THROUGH NEXT WEEK. ALL MODELS AGREE THAT TODAYS STORM SYSTEM WILL MOVE RAPIDLY TO THE EAST AND THROUGH THE REGION TODAY. THIS WILL BE FOLLOWED BY A SERIES OF INSIDE SLIDERS THAT WILL PASS JUST NORTH OF THE REGION THROUGH THE REMAINDER OF THE SEVEN DAY FORECAST PERIOD. THE FIRST INSIDE SLIDER WILL FOLLOW DIRECTLY ON THE HEALS OF TODAYS DEPARTING STORM. THIS WILL BE A DRIER TYPE OF FRONTAL PASSAGE THAT WILL PROBABLY GIVE US A CHANCE FOR SOME SHOWERS ON MONDAY...BUT WILL PROBABLY NOT BE OF MUCH CONSEQUENCE COMPARED TO TODAYS EVENT. MODELS THEN HAVE A PERIOD OF MAINLY ZONAL FLOW EARLY TUESDAY...FOLLOWED BY YET ANOTHER INSIDE SLIDER LATE TUESDAY AND WEDNESDAY. THIS WILL PRESENT A CHANCE FOR SHOWERS...MAINLY TO THE CENTRAL COAST. LATE WEDNESDAY AND THURSDAY ALL THE MODELS HAVE WEAK RIDGING OVER THE REGION...SO IT SHOULD BE THE DRIEST DAY OF THE WEEK. THEN THE MODELS CALL FOR TWO MORE INSIDE SLIDERS...THE FIRST ON FRIDAY AND YET ANOTHER LATE SATURDAY INTO SUNDAY. THE BOTTOM LINE IS THAT THE OUTLOOK PERIOD WILL BE UNSETTLED WITH A NUMBER OF CHANCES FOR LIGHT RAIN AND SHOWERS...BUT NONE OF THESE SYSTEMS SHOULD BE AS POWERFUL AND DURABLE AS THE STORM THAT HAS BEEN IMPACTING THE REGION FOR MOST OF THE LAST WEEK. && .AVIATION... 27/1130Z ONLY LOW TO MODERATE CONFIDENCE IN 12Z TAFS. LATEST SATELLITE AND RADAR DATA SHOWS MAIN RAIN BAND SHOULD EXIT THE AREA THIS MORNING. MORE CONVECTIVE ACTIVITY CAN BE EXPECTED LATER THIS MORNING AND AFTERNOON AS THE LOW CENTER MOVES OVER THE AREA. AS THE LOW CENTER MOVES OVERHEAD...WILL EXPECT A CHANCE OF SHOWERS AND THUNDERSTORMS JUST ABOUT ANYWHERE. WILL GO WITH VCSH AND VCTS FOR ALL TAF SITES LATE THIS MORNING AND AFTERNOON...WITH VCSH PREDOMINATE OVERNIGHT. CIGS AND VSBYS WILL BE ALL OVER THE PLACE RANGING FROM IFR TO MVFR. GUSTY SOUTHEAST TO EAST FLOW WILL CONTINUE FOR SITES SOUTH OF POINT CONCEPTION THROUGH THE AFTERNOON...BEFORE SWITCHING TO A SOUTH TO SOUTHWEST DIRECTION THIS EVENING. KLAX...ONLY LOW TO MODERATE CONFIDENCE IN CIG AND VSBY FORECAST THROUGH THE PERIOD. GUSTY EAST TO SOUTHEAST WINDS WILL CONTINUE THROUGH THIS AFTERNOON WITH GUSTS TO AROUND 25 KT LIKELY. WILL HAVE CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS...WARRANTING VCSH AND VCTS FORECASTS. KBUR...MODERATE CONFIDENCE IN CIG AND VSBY FORECAST THROUGH THE PERIOD. GUSTY SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE TAF PERIOD...WITH GUSTS TO AROUND 25 KT LIKELY. WILL HAVE CONTINUED THREAT OF SHOWERS AND THUNDERSTORMS...WARRANTING VCSH AND VCTS FORECASTS. $$ .LOX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING (SEE LAXWSWLOX). HIGH WIND WARNING (SEE LAXNPWLOX). FLOOD WATCH (SEE LAXFFALOX). WIND ADVISORY (SEE LAXNPWLOX). GALE WARNING (SEE LAXCWFLOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && $$ PUBLIC...RORKE/DANIELSON AVIATION...THOMPSON WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
300 PM EST SUN JAN 27 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE AREA THROUGH MONDAY. THIS HIGH WILL DRIFT OFF THE MID-ATLANTIC COAST MONDAY NIGHT AND TUESDAY ALLOWING FOR THE NEXT COLD FRONT TO SLOWLY PASS THROUGH THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN BEHIND THIS FRONT FOR WEDNESDAY AND THURSDAY. THE NEXT STORM SYSTEM WILL ARRIVE OVERNIGHT THURSDAY AND FRIDAY...BUT HIGH PRESSURE WILL RETURN FOR NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... WATER VAPOR LOOP SHOWS A TROUGH MOVING OFF THE DELMARVA AS AN UPPER LOW SINKS SOUTHEAST OVER PENNSYLVANIA. RIDGING IS OCCURRING OVER THE ROCKIES AS AN UPPER LOW TROUGH APPROACHES AN UPPER LOW OFF THE CALIFORNIA COAST. ACARS 400-250MB WIND OBSERVATIONS REVEAL SPLIT FLOW OVER THE ROCKIES...WITH A WESTERLY 120-160KT JET AT THE BASE OF THE UPPER TROUGH OVER THE SOUTHEAST CONUS. 11Z SURFACE ANALYSIS PLACED A CYCLONE DEEPER THAN 1011MB WELL OFF THE DELMARVA...WITH A COLD FRONT TRAILING SOUTHWEST THROUGH CENTRAL FLORIDA. A BACKDOOR COLD FRONT HAS SAGGED THROUGH THE NORTHERN PORTION OF NEW ENGLAND...WITH A SURFACE REFLECTION TROUGH BISECTING PENNSYLVANIA FROM NORTHWEST TO SOUTHEAST. A STATIONARY BOUNDARY EXTENDED SOUTHEAST FROM SOUTH DAKOTA INTO THE TENNESSEE VALLEY. FINALLY...A 1027MB ANTICYCLONE DOMINATED THE WESTERN GULF STATES. HIGH PRESSURE BUILDS INTO THE APPALACHIANS TONIGHT AS ATLANTIC CYCLONE DEEPENS OFF OF NEW ENGLAND. THIS WILL END ANY REMAINING FLURRIES ACROSS THE HIGHER TERRAIN...AND ALLOW STRATO-CU EAST OF THE MOUNTAINS TO DIMINISH THIS EVENING. TEMPERATURES 5-7F BELOW LAST NIGHTS READINGS ARE EXPECTED. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... HEIGHT RISES ALOFT WILL CONTINUE TO SPREAD NORTHEAST TOMORROW... ALLOWING SURFACE RIDGE TO MOVE INTO THE REGION. SUNNY SKIES EXPECTED EAST OF THE MOUNTAINS...AS UPSLOPE MOUNTAIN MOISTURE DISSIPATES THROUGH THE DAY. WHILE NORTHWEST WINDS CONTINUE THROUGH THE AFTERNOON...WARM ADVECTION SHOULD LEAD TO TEMPERATURES 5-10F WARMER THAN TODAY. HIPRES RDG WL BE ATOP CWFA MON EVE...BUT CDFNT WL BE PRESSING EWD. AS HAS BEEN THE CASE OF LATE...THE GFS HAS BEEN MUCH MORE AGGRESSIVE THAN NAM IN PUSHING PCPN AHD OF FRNT. ALTHO NAM HAS HAD ITS OWN SET OF PERFORMANCE ISSUES...IT HAS THE BACKING OF ECMWF IN A SLOWER ARRIVAL TIME...AND WL BE PREFERRED CONSIDERING LLVLS WL NEED TO SATURATE FIRST /A KNOWN GFS BIAS/. IN FACT...GFS MDL SNDGS DEPICT PCPN FALLING FM 10 THSND FT BASES LATE MON NGT. DO THINK THAT THE MID DECK CLDS WL ROLL IN...FOR INCR CLD FCST...AND WAA WL ALSO IMPACT MIN-T...SPCLY ACRS THE RDGS. MOS GDNC WASHING THIS FEATURE OUT..AND ULTIMATELY MIN-T FCST WL BE A PINCH ABV MOS MOST PLACES... SPCLY WRN SITES. HV TRIMMED MON NGT POPS FRTHR...BUT HVNT TTLY ELIMINATED THEM...KEEPING JUST SCHC APPLCHNS. MOST LIKELY...PCPN WLL DRAG DWN WARM NOSE...IF TEMPS ARENT ALREADY ABV FRZG AT PCPN ONSET. THE XCPTN THERE MAY BE WRN ALLEGANY...WHERE SCHC WL BE FOR RA/FZRA. PCPN WL SPREAD ACRS CWFA TUE IN RESPONSE TO DECENT ISENTROPIC UPGLIDE. LIKELIES WL SNEAK INTO WRN SXNS IN THE AFTN. THE PTYPE FOR THIS EVENT WL BE RA. AGN...CANT RULE OUT TEMPS JUST BLO FRZG MRB/HGR...BUT ITS NOT A FAVORED SOLN. GRIDS WL MNTN SCHC FZRA AS WORST CASE SCENARIO ONLY. TUE NGT WL PROVIDE HIEST POPS...AS THAT WL BE WHEN CFP OCCURS. GDNC SLOWING FROPA DOWN A LTL FM PRVS CYCLE. LLVL FORCING SHUD BE FAVORABLE...AS THERE/S TIGHT H8 THERMAL PACKING COINCIDENT W/ CDFNT. BUT...THERE/S STILL THE LINGERING ISSUE OF WHETHER MSTR WL CUT OFF IN THE WARM SECTOR...OR SOME WL LINGER BHD FRONT. THUS...WL HV RASN IN THE HIGHLANDS AFTR MIDNGT. DUE TO THE SLOWER EVOLUTION...HV INCL SHC FOR A LINGERING SHRA I-95 EAST ELY WED MRNG. OTRW...WED WL BE A DAY OF HIPRES...SCOURING OUT CLDS THRU DAY TEMPS OVRALL WL BE ON THE MILD SIDE...SPCLY CONSIDERING RECENT PAST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIPRES WL CONT WED NGT...W/ THE RETURN FLOW BRINGING CLDS BACK THU. STRENGTH/TIMING DISCREPANCIES STILL EXIST BTWN GFS/ECMWF REGARDING THE 2ND STORM SYSTEM TOO...W/ GFS ONCE AGN COMING IN FAST AND STRONG. THE 06Z OP GFS RUN 11 MB STRONGER AND DISPLACED FRTHR N THAN THE 00Z ENSEMBLE RUN. IN THAT REGARD...THE EURO IS CLOSER TO GEFS. HPC HAS PREFERRED AN EURO/ENSEMBLE BLEND...AND I DO TOO. REGARDLESS...THE TRACK APPEARS TO BE SOMEWHERE INVOF OHVLY/ERN GRTLKS...WHICH WUD ALLW ENUF WARMTH TO FLOW NWD AHD OF CYCLONE SO THAT MAJOR PTYPE WUD BE RAIN. CONCENTRATED POPS IN THE THU NGT-FRI NGT TIMEFRAME. ULTIMATELY...THU NGT PTYPE QSTNBL...CUD DROP BLO FRZG W OF I-95. SIMILARLY...RA CUD CHG BACK TO SNW BEFORE ENDING FRI NGT IF MSTR LINGERS LONG ENUF. AT THIS STAGE...KEPT IT RA/SN...AS THERE/S PLENTY OF TIME FOR GDNC TO CHG SOLNS. ONE THING/S APPARENT FM THIS VANTAGE PT...HIPRES SHUD BUILD IN FOR NXT WKND. HEMI PTTN MILD FOR LT JAN...AND 50F VERY REACHABLE SRN/ERN CWFA. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... REMAINING STRATO-CU EXPECTED TO MIX OUT DURING THE LATE AFTERNOON AND EVENING EAST OF THE MOUNTAINS AS HIGH PRESSURE BUILDS IN. NORTHWEST WINDS SLACKEN WITH SUNSET AND REDEVELOP WITH MID MORNING MIXING. FLGT RESTRICTIONS /MVFR-LCL IFR/ XPCTD W/ TWO STORM SYSTMS...TUE- TUE NGT...AND AGN THU NGT-FRI NGT. IN EACH CASE...THE PREDOMINANT PTYPE WL BE RA. && .MARINE... BRIEF PERIOD OF NORTHWEST WIND GUSTS OF 20 KNOTS SPREADING SOUTHEAST FROM DC MID TO LATE AFTERNOON...ON LEADING EDGE OF BUILDING HIGH PRESSURE. HAVE ISSUED A MARINE WEATHER STATEMENT DISCUSSING DETAILS. SMALL CRAFT ADVISORY CONDITIONS DEVELOPING IN TANGIER SOUND THIS MID AFTERNOON...EXPECTED TO DEVELOP NORTHWARD AS PRESSURE GRADIENT STRENGTHENS TONIGHT. TRIMMED LOWER TIDAL POTOMAC FROM ADVISORY AS AS PRESSURE GRADIENT PATTERN AND STEEPER MARINE LAPSE RATES FAVOR THE BAY. SMALL CRAFT CONDITIONS EXPECTED TO GRADUALLY DIMINISH DURING THE MID MORNING HOURS AS HIGH PRESSURE BUILDS IN. SCA CONDS MAY BE REALIZED AGN LT TUE NGT-WED W/ A CFP. THERES A SMALL CHC IN THE SLY CHANNELING AHD OF FROPA...BUT THE BETTER MIXING WL COME WED IN WLY FLOW AFTER FROPA. A 2ND STORM WL MV UP OHVLY-ERN GRTLKS END OF WK...WHICH WL ALSO HV SCA PSBLTIES. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EST MONDAY FOR ANZ530>533. SMALL CRAFT ADVISORY UNTIL 11 AM EST MONDAY FOR ANZ534. && $$ SYNOPSIS...HTS NEAR TERM...ROGOWSKI SHORT TERM...ROGOWSKI/HTS LONG TERM...HTS AVIATION...ROGOWSKI/HTS MARINE...ROGOWSKI/HTS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
904 AM EST SAT JAN 26 2008 .SYNOPSIS... HIGH PRESSURE WILL DRIFT OFF THE MID-ATLANTIC COAST TODAY. AN UPPER LEVEL DISTURBANCE WILL MOVE FROM WEST TO EAST ACROSS THE AREA OVERNIGHT INTO EARLY SUNDAY...THEN HIGH PRESSURE RETURNS LATER SUNDAY THROUGH MONDAY. THE NEXT COLD FRONT WILL MOVE THROUGH THE REGION LATER TUESDAY INTO TUESDAY NIGHT. HIGH PRESSURE WILL BUILD ACROSS THE AREA FOR THE MIDDLE PART OF NEXT WEEK BUT THE NEXT STORM SYSTEM WILL APPROACH THE REGION FOR THURSDAY NIGHT AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WATER VAPOR LOOP SHOWS A PAIR OF SHORT WAVES SHEARING EAST ACROSS THE MIDWEST AND UPPER PLAINS. A DRY SLOT WAS NOTED FROM ARKLATEK NORTHEAST INTO THE MID ATLANTIC. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 125-165KT JET FROM BAJA CALIFORNIA ACROSS THE PLAINS AND INTO THE SOUTHEAST CONUS. 11Z SURFACE ANALYSIS PLACED 1029MB ANTICYCLONE OFF THE NORTH CAROLINA COAST...WITH A 1023MB CYCLONE DEVELOPING ALONG THE SOUTH CAROLINA COAST. FURTHER SOUTHWEST ALONG THE BAROCLINIC ZONE IS A 1020MB CYCLONE NEAR NEW ORLEANS. A SECOND BAROCLINIC ZONE IS DEVELOPING FROM A TRIPLE POINT NEAR MINNEAPOLIS...SOUTHEAST THROUGH THE TENNESSEE VALLEY. LOCAL GPS PRECIPITABLE WATER SENSORS INDICATE VALUES INCREASED FROM ABOUT 0.15" DURING THE EVENING TO 0.3" THIS MORNING AS MID DECK OVERSPREAD THE REGION. THIS RESULTED IN RISING TEMPERATURES AND DEW POINTS LATE LAST NIGHT. 12Z LAPS ANALYSIS SHOWS DEW POINT DEPRESSIONS HAVE FALLEN INTO THE SINGLE DIGITS ACROSS THE AREA...EXCEPT AT THE HIGHER TERRAIN...AND NORTH CENTRAL MARYLAND. RADAR ECHOES FROM KLWX ARE AT 6-8KFT ...INDICATIVE OF SUB-CLOUD VIRGA. HAVE NOT HEARD OF ANY SNOW REPORTS THIS MORNING FROM THIS WARM ADVECTION PROCESS. SECOND PRECIPITATION MECHANISM TODAY WILL BE THE CYCLONE DEVELOPING OFF THE SOUTH CAROLINA COAST...ALTHOUGH ALL GUIDANCE INDICATES THIS PRECIPITATION WELL SOUTHEAST OF THE AREA...APPROACHING SOUTHEAST VIRGINIA THIS EVENING. THIS LEAVES US WITH THE SHORT WAVE NOW LOCATED OVER LACROSSE WISCONSIN. PRECIPITATION ASSOCIATED WITH THIS SYSTEM WILL SPREAD EAST ACROSS THE GREAT LAKES AND INTO NEW ENGLAND THIS AFTERNOON. A SECOND AREA OF PRECIPITATION IS EXPECTED TO DEVELOP ACROSS THE OHIO VALLEY BEGINNING THIS EVENING...AND THIS IS THE FEATURE THAT COULD SPREAD SOME LIGHT SNOW ACROSS THE REGION TONIGHT. TEMPERATURE FORECAST IS ON LOW SIDE OF GUIDANCE DUE TO CLOUD COVER. LIGHT WINDS EXPECTED WITH SURFACE PRESSURE COL ACROSS THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... A STRONG SHORTWAVE IN THE MID LEVELS WILL DROP SOUTH TONIGHT. AT THIS TIME...THE TROUGH AXIS REMAINS POSITIVELY TILTED WITH THE UPPER LOW CLOSING OFF OVER THE WESTERN ATLANTIC BY EARLY SUNDAY. THE COASTAL LOW IS PROGGED MOVE NORTH UP THE COAST OF THE CAROLINAS OVERNIGHT. THIS SYSTEM SHOULD STAY WELL EAST OF THE DELMARVA. WITH THE STRONG 500MB ENERGY DIVING SOUTHWARD...SOME SNOW SHOWERS ARE POSSIBLE MAINLY DURING THE EVENING AND OVERNIGHT HOURS. THE LOW LEVELS ARE NOT PROGGED TO MOISTEN UP CONSIDERABLY (CURRENTLY VERY DRY)...SO NOT MUCH QPF IS ANTICIPATED. THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE HIGHEST CHANCES OF SNOW IN THE WEST AND ALONG THE MD/PA BORDER. HOWEVER...POPS WILL ONLY RANGE FROM SLIGHT CHANCE IN THE SOUTH...TO HIGH END CHANCE IN THE WEST. THE BEST ACCUMULATIONS OF ANY SNOW WILL BE IN THE NORTHWEST...AND STILL UNDER ANY HEADLINE CRITERIA. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AN UPPER-LEVEL DISTURBANCE WILL ROTATE THROUGH THE REGION SUNDAY MORNING. THIS SYSTEM WILL BE RAPIDLY INTENSIFYING AS IT MOVES EAST OF THE REGION SUNDAY AFTERNOON AND OUT TO SEA BY SUNDAY NIGHT. THIS SYSTEM WILL PHASE WITH SOUTHERN BRANCH ENERGY TO FORM A STRONG COASTAL STORM...BUT ALL GUIDANCE CONTINUES TO SUGGEST THAT THIS DEVELOPMENT IS WELL OUT TO SEA AWAY FROM OUR REGION. DESPITE VERY DRY LOW-LEVELS...THERE MAY BE JUST ENOUGH FORCING AND MID-LEVEL MOISTURE FOR A FEW SNOW SHOWERS SUNDAY MORNING WITH THE PASSAGE OF THE DISTURBANCE. THE BEST CHANCE FOR SNOW SHOWERS WILL BE ACROSS THE POTOMAC HIGHLANDS. TEMPERATURES SUNDAY WILL BE CLOSE TO NORMAL FOR THIS TIME OF YEAR. MONDAY AND TUESDAY NIGHT: HIGH PRESSURE WILL BRING DRY AND SEASONABLE CONDITIONS FOR MONDAY. THIS HIGH WILL DRIFT OFF THE COAST MONDAY NIGHT AND THE NEXT COLD FRONT WILL APPROACH THE REGION TUESDAY BEFORE FINALLY PASSING THROUGH THE REGION TUESDAY NIGHT. THIS FRONT WILL BRING A CHANCE FOR RAIN TO MOST LOCATIONS...BUT DEPENDING ON THE EXACT TIMING OF PRECIPITATION THERE CAN BE SOME MIXED PRECIPITATION MAINLY FOR LOCATIONS WEST OF THE BLUE RIDGE OVERNIGHT MONDAY INTO TUESDAY. DRIER AIR APPEARS THAT IT WILL MOVE IN QUICKLY BEHIND THE FRONT LATE TUESDAY NIGHT BUT THERE MAY BE JUST ENOUGH MOISTURE FOR A FEW UPSLOPE SNOW SHOWERS ACROSS THE POTOMAC HIGHLANDS. WEDNESDAY THROUGH FRIDAY: HIGH PRESSURE WILL BRING DRY AND SEASONABLE CONDITIONS FOR WEDNESDAY AND THURSDAY. THE NEXT STORM SYSTEM WILL BRING A CHANCE FOR PRECIPITATION THURSDAY NIGHT AND FRIDAY. DEPENDING ON THE AMOUNT OF LOW-LEVEL COLD AIR IN PLACE...PTYPE MAY BE AN ISSUE MAINLY NORTH AND WEST OF THE CITIES. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... CEILINGS ARE FORECAST TO REMAIN VFR THROUGH MOST OF TODAY...BUT ARE FORECAST TO NEAR MVFR TONIGHT AS AN UPPER LEVEL DISTURBANCE MOVES OVERHEAD. SCATTERED SNOW SHOWERS ARE POSSIBLE TONIGHT...BUT HAVE LITTLE CONFIDENCE AT THIS TIME THAT THEY WOULD SIGNIFICANTLY REDUCE CEILINGS/VISIBILITIES. WINDS WILL REMAIN LIGHT TODAY UNDER INFLUENCE FROM HIGH PRESSURE...AND THEN SHIFT AROUND TO THE NORTH OVERNIGHT AS A LOW PRESSURE SYSTEM DEVELOPS WELL OFF THE EAST COAST. VFR CONDITIONS ARE EXPECTED FOR SUNDAY AND MONDAY. THE NEXT COLD FRONT WILL BRING A CHANCE FOR MVFR/IFR CIGS AND VSBYS TUESDAY INTO TUESDAY NIGHT. VFR CONDITIONS ARE EXPECTED FOR WEDNESDAY AND THURSDAY...THEN THE NEXT STORM SYSTEM WILL APPROACH THE TERMINALS THURSDAY NIGHT AND FRIDAY. && .MARINE... LIGHT WINDS TODAY UNDER INFLUENCE OF SURFACE HIGH PRESSURE. WINDS SHIFT TO THE NORTH TONIGHT AS LOW PRESSURE DEVELOPS WELL OFF THE EAST COAST. WINDS WILL APPROACH SCA CRITERIA FOR SUNDAY NIGHT AND MONDAY BEHIND A LOW PRESSURE SYSTEM MOVING UP THE COAST. A BETTER CHANCE FOR SCA CRITERIA IS EXPECTED TUESDAY NIGHT AND WEDNESDAY BEHIND ANOTHER COLD FRONT. THE NEXT STORM SYSTEM WILL APPROACH THE WATERS THURSDAY NIGHT AND FRIDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BJL NEAR TERM...ROGOWSKI SHORT TERM...NWL LONG TERM...BJL AVIATION...ROGOWSKI/BJL MARINE...ROGOWSKI/BJL
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
630 AM EST SAT JAN 26 2008 UPDATED AVIATION DISCUSSION .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH THE UPR LKS INCRSGLY DOMINATED BY A ZONAL POLAR BRANCH FLOW WHILE THE ARCTIC BRANCH/BITTERLY COLD AIR IS GRDLY LIFTING FARTHER TO THE N IN SRN CAN. AT 04Z...WEAK SFC-H85 RDGING IS DOMINATING THE CWA WITH 01Z TAMDAR SDNG FM SAW SHOWING A DRY AIRMASS IN PLACE (00Z PWAT 0.15 INCH FM INL TO APX)...BUT MORE CLD/SOME -SN JUST TO THE S ASSOCIATED WITH A PAIR OF SHRTWVS DRIFTING THRU THE POLAR BRANCH FLOW. THE FIRST OF THESE IS TRACKING FM CNTRL WI INTO LK MI ATTM... AND SOME LGT SN IS FALLING AS FAR N AS NE WI NEAR MNM. A SECOND SYS IS MOVING ACRS NRN IA. ALTHOUGH WV IMAGERY SUGS THIS SHRTWV IS MORE INTENSE... PCPN IS FAIRLY SPARSE...APRNTLY DUE TO DRY AIR ABV H75 AS SHOWN ON THE 00Z MPX SDNG. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND PCPN CHCS TDAY MAINLY ACRS THE S AND THEN TEMPS/SKY FOR SAT NGT THRU SUN. FOCUS FOR EARLY THIS COMING WEEK TURNS TO TIMING/IMPACT OF SFC LO THAT WL EVOLVE IN THE PLAINS E OF A DEEPENING TROF OUT W. FOR TDAY...SHRTWV NOW MOVING ACRS NRN IA PROGGED TO DRIFT ACRS SRN WI AND INTO SRN LWR MI BY 00Z SUN. TRACK OF SYS/ASSOCIATED DYNAMICS SO FAR TO THE S SUGS LTL WL FALL ACRS MOST OF THE FA. THE ONLY EXCEPTION WL BE OVER THE E DOWNWIND OF LK MI WHERE GFS/NAM PERSIST IN SHOWING A CONFLUENT SLY FLOW FM SFC-H8 OFF LK MI WITH H85 THERMAL TROF/TEMPS ARND -12C MAINTAINING STEEP LLVL LAPSE RATES. FINER RESOLUTION NAM/LOCAL HI RES MODEL SHOWS BAND OF ENHANCED CNVGC/APRNT SHSN MOVING ONSHORE IN SRN SCHOOLCRAFT COUNTY ARND 15Z UNDER MSTR UP TO H7. ALTHOUGH SHARPER LLVL CNVGC PROGGED TO WEAKEN BY LATE IN THE DAY...WL MAINTAIN GOING LIKELY/CATEGORICAL POPS IN THIS AREA THRU THE DAY WITH PERSISTENT SLY FLOW. DESPITE THESE FAIRLY IMPRESSIVE FEATURES...EVEN FINE RES MODEL QPF IS FAIRLY LGT (NO MORE THAN 0.05 INCH) WITH GUIDANCE SHOWING POOR UVV IN THE BETTER SN GROWTH LYR. STILL...LES CHART WOULD SUG UP TO 3-4 INCHES/12 HRS PSBL FM MID MRNG THRU THIS EVNG...WHEN SLY FLOW/LLVL CNVGC FINALLY FCST TO FADE WITH PASSAGE OF WEAK LO PRES TROF ARND 06Z AND INCRSGLY SHALLOW MSTR AFT 00Z SUN. WITHOUT MOISTENING OFF LK MI AND ABSENCE OF DYNAMICS... AREAS W OF P53-MNM LOOK TO REMAIN DRY DESPITE WDSPRD CLD COVER. WL CARRY ONLY LO CHC POPS IN THESE AREAS. GOING FCST HI TEMPS IN THE MID/UPR 20S SEEM ON TRACK AND CONSISTENT WITH LATEST MOS GUIDANCE. BLDG UPR RDG IN THE PLAINS FCST TO EDGE TOWARD THE UPR GRT LKS TNGT WITH STEADILY RISING HGTS/MSLP. GFS/NAM FCST SDNGS SHOW STEADILY DESCENDING SUBSIDENCE INVRN BASE...SO QUITE A BIT OF LO CLD MAY END UP TRAPPED BENEATH THIS INVRN. BUT SINCE SKIES HAVE CLRD OVER THE NRN PLAINS UNDER THE RDGING...WL FCST CONDITIONS TO BCM PCLDY OVER AT LEAST THE W HALF WHERE FCST SDNGS SHOW INVRN BASE SINKING BLO H9. EXPECT CLDS/FLURRIES TO BE MORE RESILIENT OVER THE E EVEN AFT SHSN HAVE ENDED IN THE EVNG AS FCST SDNGS SHOW INVRN BASE IN THE H85-9 RANGE AT ERY/ISQ THRU 12Z SUN. MAINTAINED MENTION OF FOG OVER THE INTERIOR W HALF AS WELL WHERE LGT WINDS WL ALLOW TEMPS TO FALL NEAR LO END OF MOS GUIDANCE. UPR RDGING/HGT RISES WL DOMINATE AGAIN ON SUN DOWNSTREAM OF DEEPENING TROF IN THE W. SINCE FCST SDNGS ARE QUITE DRY WITH LLVLS DRYING EVEN OVER THE E...EXPECT ANY MRNG CLD/FOG TO GIVE WAY TO MOSUNNY SKIES. FCST SUBSIDENCE/WAD UNDER THE RDGING FCST TO PUSH H85 TEMPS TO ARND 3C AT IWD AND -2C AT ERY BY 00Z MON. SO TEMPS WL LIKELY RISE ABV 32 AT MANY LOCATIONS...ESPECIALLY OVER THE FAR W WHERE EXPECTED SLY FLOW WL DOWNSLOPE. THE LOWEST TEMPS MAY BE ARND THE BAYS DE NOC...WHICH HAVE EXTENSIVE ICE COVER NOW. MID LVLS REMAIN QUITE DRY SUN NGT UNDER UPR RDGING IN THE UPR LKS... BUT GFS/NAM BOTH HINT AT RETURN OF LLVL MSTR BLO SUBSIDENCE INVRN OVER THE W HALF AFT 06Z AS STRG LLJ DVLPS E OF PRES FALLS TO THE W (GFS/NAM SHOW SSW WINDS AS HI AS 40-45KT AT 1K FT AT IWD BY 06Z). SINCE FCST SDNGS ARE QUITE DRY AND FA WL BE IN UNFVRBL RIGHT EXIT RGN OF H3 JET AXIS INTO MN...OPTED TO REMOVE ALL MENTION OF POPS OVER THE LAND CWA AND RESTRICT LO CHC POPS TO WRN LK SUP CLOSER TO THE DEEPER QVECTOR CNVGC ASSOCIATED WITH DEEPENING LO IN THE NRN PLAINS. GOING FCST TEMPS NEED LTL ADJUSTMENT. HAVE TRENDED BACK POPS MON MRNG AS BULK OF GUIDANCE SHOWING DRY MID LVL AIR DELAYING ONSET OF PCPN IN VIGOROUS WAD REGIME TO THE E OF DVLPG LO IN THE NRN PLAINS. SPEAKING OF DRY AIR...GFS CONTINUES TO INDICATE EVAPORATIVE COOLING WL PLAY A KEY ROLE IN DETERMINING PTYPE ON MON. FCST SDNGS WITH A LARGE DEPTH OF T>0C (BUT DRY) COOL SGNFTLY TOWARD WBLB WITH ONSET OF SHARPER DYNAMICS/MODEL QPF...SUGING PCPN WL START OUT AS A MIX OF MAINLY ZR/IP. SINCE FCST SDNGS SHOW TEMPS THRU ALL BUT THE NR SFC LYR DROPPING AOB 0C DURING TIME OF PEAK SATURATION...SUSPECT THE HEAVIEST PCPN WL FALL MAINLY AS SN IN THE AFTN/EARLY EVNG. UNCERTAINTY IS STILL THERE...SO CONTINUED MENTION OF OTHER PTYPES INTO THE AFTN/EVNG. SOME KIND OF WINTER WX ADVY WL LIKELY BE NEEDED. OTRW...SHARPENING PRES GRADIENT/ STRENTHENING SLY FLOW AHEAD OF LO PRES LIFTING NEWD THRU WRN LK SUP MAY REQUIRE WIND HEADLINES...ESPECIALLY DOWNWIND OF LK MI. ARRIVAL OF COLDER BUT DRIER AIR DURING MON NGT WL DIMINISH THE POPS AND CHG PCPN OVER MAINLY TO SN. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... VFR CONDITIONS EXPECTED TO GIVE WAY TO MVFR CIGS BY LATE THIS MORNING. COULD EVEN SEE A BIT OF LIGHT SNOW AT KSAW...BUT VSBY SHOULD REMAIN MVFR/VFR. DRIER AIR/CLEARING SKIES OVER PLAINS SHOULD MAKE IT INTO BOTH TAF SITES TOWARD DAYBREAK ON SUNDAY. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... MAIN FEATURE OF INTEREST IS A VERY STRONG LOW PRES SYSTEM MOVING FROM THE NRN PLAINS MON MORNING INTO ONTARIO BY TUE MORNING. SYSTEM WILL EASILY BE STRONG ENOUGH TO PRODUCE SRLY GALES OVER THE E HALF OF LAKE SUPERIOR MON. SWITCH TO W TO NW GALES TUE AFTN INTO WED OVER MUCH OF LAKE SUPERIOR AS ARCTIC AIR SURGES INTO THE REGION BEHIND THE LOW. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...KC AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
410 AM EST SAT JAN 26 2008 .DISCUSSION... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW ACRS NAMERICA WITH THE UPR LKS INCRSGLY DOMINATED BY A ZONAL POLAR BRANCH FLOW WHILE THE ARCTIC BRANCH/BITTERLY COLD AIR IS GRDLY LIFTING FARTHER TO THE N IN SRN CAN. AT 04Z...WEAK SFC-H85 RDGING IS DOMINATING THE CWA WITH 01Z TAMDAR SDNG FM SAW SHOWING A DRY AIRMASS IN PLACE (00Z PWAT 0.15 INCH FM INL TO APX)...BUT MORE CLD/SOME -SN JUST TO THE S ASSOCIATED WITH A PAIR OF SHRTWVS DRIFTING THRU THE POLAR BRANCH FLOW. THE FIRST OF THESE IS TRACKING FM CNTRL WI INTO LK MI ATTM... AND SOME LGT SN IS FALLING AS FAR N AS NE WI NEAR MNM. A SECOND SYS IS MOVING ACRS NRN IA. ALTHOUGH WV IMAGERY SUGS THIS SHRTWV IS MORE INTENSE... PCPN IS FAIRLY SPARSE...APRNTLY DUE TO DRY AIR ABV H75 AS SHOWN ON THE 00Z MPX SDNG. MAIN FCST CONCERNS IN THE SHORT TERM REVOLVE ARND PCPN CHCS TDAY MAINLY ACRS THE S AND THEN TEMPS/SKY FOR SAT NGT THRU SUN. FOCUS FOR EARLY THIS COMING WEEK TURNS TO TIMING/IMPACT OF SFC LO THAT WL EVOLVE IN THE PLAINS E OF A DEEPENING TROF OUT W. FOR TDAY...SHRTWV NOW MOVING ACRS NRN IA PROGGED TO DRIFT ACRS SRN WI AND INTO SRN LWR MI BY 00Z SUN. TRACK OF SYS/ASSOCIATED DYNAMICS SO FAR TO THE S SUGS LTL WL FALL ACRS MOST OF THE FA. THE ONLY EXCEPTION WL BE OVER THE E DOWNWIND OF LK MI WHERE GFS/NAM PERSIST IN SHOWING A CONFLUENT SLY FLOW FM SFC-H8 OFF LK MI WITH H85 THERMAL TROF/TEMPS ARND -12C MAINTAINING STEEP LLVL LAPSE RATES. FINER RESOLUTION NAM/LOCAL HI RES MODEL SHOWS BAND OF ENHANCED CNVGC/APRNT SHSN MOVING ONSHORE IN SRN SCHOOLCRAFT COUNTY ARND 15Z UNDER MSTR UP TO H7. ALTHOUGH SHARPER LLVL CNVGC PROGGED TO WEAKEN BY LATE IN THE DAY...WL MAINTAIN GOING LIKELY/CATEGORICAL POPS IN THIS AREA THRU THE DAY WITH PERSISTENT SLY FLOW. DESPITE THESE FAIRLY IMPRESSIVE FEATURES...EVEN FINE RES MODEL QPF IS FAIRLY LGT (NO MORE THAN 0.05 INCH) WITH GUIDANCE SHOWING POOR UVV IN THE BETTER SN GROWTH LYR. STILL...LES CHART WOULD SUG UP TO 3-4 INCHES/12 HRS PSBL FM MID MRNG THRU THIS EVNG...WHEN SLY FLOW/LLVL CNVGC FINALLY FCST TO FADE WITH PASSAGE OF WEAK LO PRES TROF ARND 06Z AND INCRSGLY SHALLOW MSTR AFT 00Z SUN. WITHOUT MOISTENING OFF LK MI AND ABSENCE OF DYNAMICS... AREAS W OF P53-MNM LOOK TO REMAIN DRY DESPITE WDSPRD CLD COVER. WL CARRY ONLY LO CHC POPS IN THESE AREAS. GOING FCST HI TEMPS IN THE MID/UPR 20S SEEM ON TRACK AND CONSISTENT WITH LATEST MOS GUIDANCE. BLDG UPR RDG IN THE PLAINS FCST TO EDGE TOWARD THE UPR GRT LKS TNGT WITH STEADILY RISING HGTS/MSLP. GFS/NAM FCST SDNGS SHOW STEADILY DESCENDING SUBSIDENCE INVRN BASE...SO QUITE A BIT OF LO CLD MAY END UP TRAPPED BENEATH THIS INVRN. BUT SINCE SKIES HAVE CLRD OVER THE NRN PLAINS UNDER THE RDGING...WL FCST CONDITIONS TO BCM PCLDY OVER AT LEAST THE W HALF WHERE FCST SDNGS SHOW INVRN BASE SINKING BLO H9. EXPECT CLDS/FLURRIES TO BE MORE RESILIENT OVER THE E EVEN AFT SHSN HAVE ENDED IN THE EVNG AS FCST SDNGS SHOW INVRN BASE IN THE H85-9 RANGE AT ERY/ISQ THRU 12Z SUN. MAINTAINED MENTION OF FOG OVER THE INTERIOR W HALF AS WELL WHERE LGT WINDS WL ALLOW TEMPS TO FALL NEAR LO END OF MOS GUIDANCE. UPR RDGING/HGT RISES WL DOMINATE AGAIN ON SUN DOWNSTREAM OF DEEPENING TROF IN THE W. SINCE FCST SDNGS ARE QUITE DRY WITH LLVLS DRYING EVEN OVER THE E...EXPECT ANY MRNG CLD/FOG TO GIVE WAY TO MOSUNNY SKIES. FCST SUBSIDENCE/WAD UNDER THE RDGING FCST TO PUSH H85 TEMPS TO ARND 3C AT IWD AND -2C AT ERY BY 00Z MON. SO TEMPS WL LIKELY RISE ABV 32 AT MANY LOCATIONS...ESPECIALLY OVER THE FAR W WHERE EXPECTED SLY FLOW WL DOWNSLOPE. THE LOWEST TEMPS MAY BE ARND THE BAYS DE NOC...WHICH HAVE EXTENSIVE ICE COVER NOW. MID LVLS REMAIN QUITE DRY SUN NGT UNDER UPR RDGING IN THE UPR LKS... BUT GFS/NAM BOTH HINT AT RETURN OF LLVL MSTR BLO SUBSIDENCE INVRN OVER THE W HALF AFT 06Z AS STRG LLJ DVLPS E OF PRES FALLS TO THE W (GFS/NAM SHOW SSW WINDS AS HI AS 40-45KT AT 1K FT AT IWD BY 06Z). SINCE FCST SDNGS ARE QUITE DRY AND FA WL BE IN UNFVRBL RIGHT EXIT RGN OF H3 JET AXIS INTO MN...OPTED TO REMOVE ALL MENTION OF POPS OVER THE LAND CWA AND RESTRICT LO CHC POPS TO WRN LK SUP CLOSER TO THE DEEPER QVECTOR CNVGC ASSOCIATED WITH DEEPENING LO IN THE NRN PLAINS. GOING FCST TEMPS NEED LTL ADJUSTMENT. HAVE TRENDED BACK POPS MON MRNG AS BULK OF GUIDANCE SHOWING DRY MID LVL AIR DELAYING ONSET OF PCPN IN VIGOROUS WAD REGIME TO THE E OF DVLPG LO IN THE NRN PLAINS. SPEAKING OF DRY AIR...GFS CONTINUES TO INDICATE EVAPORATIVE COOLING WL PLAY A KEY ROLE IN DETERMINING PTYPE ON MON. FCST SDNGS WITH A LARGE DEPTH OF T>0C (BUT DRY) COOL SGNFTLY TOWARD WBLB WITH ONSET OF SHARPER DYNAMICS/MODEL QPF...SUGING PCPN WL START OUT AS A MIX OF MAINLY ZR/IP. SINCE FCST SDNGS SHOW TEMPS THRU ALL BUT THE NR SFC LYR DROPPING AOB 0C DURING TIME OF PEAK SATURATION...SUSPECT THE HEAVIEST PCPN WL FALL MAINLY AS SN IN THE AFTN/EARLY EVNG. UNCERTAINTY IS STILL THERE...SO CONTINUED MENTION OF OTHER PTYPES INTO THE AFTN/EVNG. SOME KIND OF WINTER WX ADVY WL LIKELY BE NEEDED. OTRW...SHARPENING PRES GRADIENT/ STRENTHENING SLY FLOW AHEAD OF LO PRES LIFTING NEWD THRU WRN LK SUP MAY REQUIRE WIND HEADLINES...ESPECIALLY DOWNWIND OF LK MI. ARRIVAL OF COLDER BUT DRIER AIR DURING MON NGT WL DIMINISH THE POPS AND CHG PCPN OVER MAINLY TO SN. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... VFR CONDITIONS SHOULD GENERALLY PREVAIL AT KCMX AND KSAW THROUGH MUCH OF THE NIGHT AS MID/HIGH LEVEL MOISTURE INCREASES IN ADVANCE OF THE NEXT SYSTEM APPROACHING FROM THE CENTRAL PLAINS. LOWER MVFR CIGS LIKELY ARRIVE A FEW HRS BEFORE DAYBREAK AT BOTH SITES. MVFR CIGS SHOULD CONTINUE THROUGH REST OF THE TAF PERIOD. BETTER CHANCE OF SOME SNOW WILL BE AT KSAW LATER THIS MORNING. EXPECT RESTRICTION TO VSBY OF AROUND 3SM. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... MAIN FEATURE OF INTEREST IS A VERY STRONG LOW PRES SYSTEM MOVING FROM THE NRN PLAINS MON MORNING INTO ONTARIO BY TUE MORNING. SYSTEM WILL EASILY BE STRONG ENOUGH TO PRODUCE SRLY GALES OVER THE E HALF OF LAKE SUPERIOR MON. SWITCH TO W TO NW GALES TUE AFTN INTO WED OVER MUCH OF LAKE SUPERIOR AS ARCTIC AIR SURGES INTO THE REGION BEHIND THE LOW. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...KC AVIATION...VOSS MARINE...JLA
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
309 PM CST SUN JAN 27 2008 .SYNOPSIS... H5 TROUGH DIGGING INTO CALIFORNIA COAST WITH BROAD H5 RIDGE OVER THE CENTRAL CONUS. && .DISCUSSION... MODELS IN GOOD AGREEMENT IN NEAR TERM AND HAVE USED BLEND FOR THE FORECAST. GOOD CONFIDENCE IN FORECAST. HAVE LOST A LOT OF SNOW COVER TODAY AS TEMPERATURES TO 63F AT KTIF AND 59F AT KBBW. KONL WITH HIGHEST SNOW COVER EVEN GOT TO 45F BRIEFLY. VERY WARM ALOFT AND WITH CLOUD COVER TEMPERATURES WILL BE SOMEWHAT WARMER TONIGHT. WEAK WAVE MOVING THROUGH WESTERN AND NORTH CENTRAL NEBRASKA MONDAY IN NORTHEAST FLOW WITH A SCHC RAINSHOWERS NORTHEAST ZONES. FROPA NOT EXPECTED TILL AFTER 00Z TUE SO NOT A LOT TO HOLD TEMPERATURES BACK AHEAD OF FRONT. GOOD MIXING AHEAD OF FRONT WITH TEMPERATURES SIMILAR TO TODAYS. SCHC LIGHT SNOW TUESDAY NIGHT WITH FROPA BREEZY WITH FROPA BUT SHOULD REMAIN BELOW ADVISORY CRITERIA. BREEZY THROUGH THE DAY TUESDAY WITH 30`S SOUTHWEST AND AROUND 20 NORTHEAST. WAA TUESDAY NIGHT INTO WEDNESDAY AS SFC LOW DEVELOPS OVER THE EASTERN PLAINS OF COLORADO. HELD TEMPERATURES UP SOME AHEAD OF APPROACHING TROUGH. MODELS STILL HAVING PROBLEMS WITH TROUGH POSITION. SOUTHERLY TRACK FAVORED AND HAVE LEFT DRY FOR NOW. LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY). SHORT WAVE TROUGH MOVES INTO THE SOUTHERN PLAINS WEDNESDAY NIGHT AND THURSDAY...WITH SURFACE LOW TAKING SHAPE PER GFS AND ECMWF WEDNESDAY NIGHT INVOF TEXAS/OKLAHOMA PANHANDLES. FLOW AROUND LOW WILL BRING UPSLOPE FLOW ACROSS THE AREA WEDNESDAY NIGHT INTO THURSDAY MORNING...SO WILL CONTINUE SLIGHT CHANCE POPS. SYSTEM MOVES TO OUR SOUTHEAST LATER IN THE DAY THURSDAY AND PRECIP SHIELD MAY BRUSH EASTERN SECTIONS...THEREFORE WILL KEEP SLIGHT CHANCES GOING INTO THE AFTERNOON HOURS ACROSS THE CENTRAL AND EAST. ANOTHER SYSTEM TO WATCH FOR SATURDAY...BUT WITH UNCERTAINTIES WILL CONTINUE TO LEAVE PRECIP OUT OF THE FORECAST. ON THURSDAY TEMPS SOMEWHAT BELOW NORMAL...ESPECIALLY NORTHEAST SECTIONS. FOR FRIDAY THROUGH SUNDAY TEMPS LOOKING TO AVERAGE ABOUT NORMAL FOR THIS TIME OF YEAR...WITH HIGHS MAINLY IN THE 30S AND LOWS BETWEEN 5 AND 15 DEGREES. && .AVIATION... DELAY IN COLD FRONTAL PASSAGE ON MONDAY WILL LEAD TO ANOTHER BREEZY AND WARM DAY. WINDS OF 15 TO 30 MPH FROM THE SOUTHWEST WILL BE ABOUT ONLY NUISANCE TO LIGHT AIRCRAFT AS VFR CONDITIONS WILL BE IN PLACE OVER THE NEXT 24 HOURS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TAYLOR/POWER/13
AREA FORECAST DISCUSSION
NWS BUFFALO NY
252 PM EST SUN JAN 27 2008 .SYNOPSIS... THE UPCOMING WEEK WILL FEATURE VERY CHANGEABLE CONDITIONS BUT AVERAGE OUT ON THE MILD SIDE. HIGH PRESSURE OVER THE EASTERN LAKES WILL SLIDE SLOWLY EASTWARD TONIGHT AND MONDAY AND PROVIDE DRY WEATHER WITH INCREASING SUNSHINE MONDAY AFTERNOON. A SOUTHERLY FLOW OF MUCH WARMER AIR WILL THEN OVERSPREAD OUR REGION ON TUESDAY AHEAD OF A SHARP COLD FRONT WHICH WILL CROSS THE AREA LATE TUESDAY NIGHT. WINDY COLDER CONDITIONS WILL FOLLOW THE FRONT WEDNESDAY WITH SOME LIMITED LAKE EFFECT...BUT ANOTHER HIGH SHOULD PROVIDE A DRY MILDER DAY AGAIN ON THURSDAY. ANOTHER STORM WILL MOVE UP FROM THE OHIO VALLEY INTO THE LAKES ON FRIDAY AND PROVIDE ANOTHER SHOT OF RAIN OR MIXED PRECIPITATION. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... MOST OF WESTERN AND CENTRAL NY BEING TREATED TO A BONUS DAY TODAY WITH PLENTY OF BRIGHT SUNSHINE AND LGT WINDS. THIS DESPITE A FAIRLY SATURATED LOWER ATMOSPHERE...BUT JUST ENOUGH SUBSIDENCE DEVELOPED BTWN UPPER WAVE OVER MICH AND DEEPENING COASTAL STORM OFF CAPE COD. WE DO EXPECT THE STRATUS TO REDEVELOP TONIGHT...AS WARMER AIR ADVECTS EASTWARD IN EARNEST WITH 850 MB TEMPS RISING SEVERAL DEGREES...AND STRENGTHENING THE INVERSION. WE ALSO HAVE A RESIDUAL AREA OF LOW CLOUD TO OUR WEST OVER SRN ONTARIO AND LOWER MICH...ASSOCIATED WITH UPPER IMPULSE WHICH SHOULD SHEAR OFF TO OUR SOUTHEAST LATER TONIGHT. TEMPS WILL BE A TOUGH CALL TONIGHT... DEPENDING ON HOW FAST WE CLOUD OVER AGAIN. WILL GO WITH GUID TEMPS MOSTLY L-M 20S BUT COULD GET COLDER IF WE STAY CLEAR LONGER. FOG COULD BE AN ISSUE IF THAT OCCURS TOO. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/... WARM ADVECTION WILL BE STORY FOR FIRST 36 HOURS OF THIS PERIOD...AND AS IT WAS TODAY...MONDAY`S PROBLEM WILL BE EXTENT OF LOW CLOUD AND TIMING OF BURNOFF. INVERSION WILL BE STRENGTHENING DURING THE MORNING WITH 850 MB TEMPS RISING ABOVE ZERO SO HAVE TO FIGURE ON LOW CLOUD THEN...BUT GOOD SUBSIDENCE SHOULD MIX IT OUT DURING AFTERNOON SO WILL PLAY CLOUDS GIVING WAY TO SUN IN AFTERNOON. SHOULD BE A PLEASANT DAY WITH TEMPS NUDGING 40...BUT AGAIN CAN VARY FROM L-M 30S IF CLOUDS HANG TOUGH TO L-M 40S WITH MORE SUN. MODELS AT VARIANCE MON NT WITH NAM/ETA TOTALLY DRY WHILE GFS BRINGS A WEAKENING AREA OF SHOWERS ASSOC WITH MID LEVEL WARM FRONT INTO WEST AFTER MDNT. LATEST SREF JUST BARELY BRUSHES WEST AND CLIMO SUGGESTS LITTLE OR NONE WITH SOUTHERLY DOWNSLOPE...BUT WILL BRING LOW CHC SHOWERS IN WEST OF GENESEE RIVER LATE MON NT. SHOULD BE WARM ENOUGH FOR LIQUID IF THIS DOES INDEED OCCUR...ALTHOUGH WILL CARRY LOW CHC FZ RAIN BRIEFLY IN SRN TIER VALLEYS. TUES WILL BE A VERY MILD DAY WITH 850 MB TEMPS IN +6C RANGE. WE SHOULD HAVE A GOOD SOUTHERLY FLOW TO MIX THIS DOWN...BUT ALSO PLENTY OF CLOUD. WARMER NAM TEMPS LOOK MORE REASONABLE...M-U 40S EASILY...COULD EVEN BREAK 50 IN DOWNSLOPE AREAS OF LAKE PLAIN. BULK OF DAY WILL BE DRY...WILL JUST CARRY CHC POPS FOR SCATD SHOWERS. NEXT PLAYER WILL BE THE SHARP COLD FRONT PROGGED TO CROSS THE REGION TUES NT. WILL USE USUALLY RELIABLE GFS FOR TIMING WITH FROPA AT BUF AROUND 07Z AND ART BY 11Z. (NAM IS ABOUT 3 HRS FASTER). WILL CARRY HIGH LIKELY FOR SHOWERS AHEAD OF FRONT...A BRIEF CHANGE TO SNOW SHOWERS BEHIND IT. BIG STORY WILL BE THE WIND ON WED. VERY STRONG GRADIENT BETWEEN 974 MB LOW LIFTING UP ACROSS ONTARIO AND WESTERN QUEBEC AND 1024 RIDGE OVER OHIO VALLEY...WILL LIKELY SEE WIND ADVISORY CRITERIA MET WITH GUSTS UP NEAR 50 MPH...WILL HIGHLITE IN HWO. TEMPS WILL TUMBLE INTO 20S. THERE WILL BE LK EFFECT POTENTIAL...BUT WINDS MAY BE TOO STRONG INITIALLY WED MORNING...IT MAY SET UP LATER WED AND WED NT EAST OF THE LAKES ON A 270 FLOW...BUT IT WILL BE BRIEF AS RIDGE APPROACHES THURS. SEE LONG TERM BELOW. && .LONG TERM /THURSDAY THROUGH SUNDAY/... THE ROLLER COASTER RIDE WILL CONTINUE IN THE LONG TERM WITH A VERY ACTIVE WEATHER REGIME SETTING UP ACROSS NOAM. THE NORTHERN HEMISPHERIC FLOW PATTERN SUGGESTS THE MEAN TROUGH WILL REMAIN ACROSS THE WESTERN CONUS THROUGH THE PERIOD...AND THE OPERATIONAL AND ENSEMBLE GUIDANCE GENERALLY AGREES. THIS WILL KEEP AN ACTIVE SOUTHWEST FLOW STORM TRACK ACROSS THE CONUS...TYPICAL OF A LA NINA BASE STATE AND NEGATIVE PNA PATTERN. THE ARCTIC OSCILLATION IS FORECAST TO REMAIN POSITIVE THROUGH THE PERIOD WITH A NEAR NEUTRAL NAO...INDICATIVE OF A LACK OF HIGH LATITUDE BLOCKING WHICH WILL PREVENT ANY LASTING COLD. ANOTHER MAJOR PACIFIC SHORTWAVE IS FORECAST TO EJECT OUT OF THE MEAN WESTERN CONUS TROUGH AND MOVE TOWARDS THE EASTERN GREAT LAKES BY FRI OR SAT. THERE CONTINUES TO BE SIGNIFICANT MODEL DIFFERENCES WITH RESPECT TO THE TIMING AND TRACK OF THIS FEATURE. GFS AND ITS GEFS ENSEMBLES ARE IN THE FASTER CAMP...BRINGING PRECIP INTO WESTERN NY AS EARLY AS LATE THURSDAY NIGHT. ECMWF/GEM ALONG WITH MOST OF THE GEM ENSEMBLE MEMBERS ARE 12-18 HOURS SLOWER AND SHOW THE MAJORITY OF PRECIP HOLDING OFF UNTIL FRI NIGHT AND SAT. MOST OF THE GEFS ENSEMBLE MEMBERS FOLLOW A TRACK SIMILAR TO THE OPERATIONAL GFS. THE CANADIAN ENSEMBLES SHOW A WIDER ENVELOPE OF POSSIBLE TRACKS...WITH A RANGE ANYWHERE FROM SOUTHERN LOWER MICHIGAN TO ALONG THE EASTERN SEABOARD. WITH THE UNCERTAINTY IN TIMING...HAVE CAPPED POPS AT HIGH CHANCE FOR NOW AS THIS IS STILL A DAY 5 FORECAST AND ATTEMPTING TO TIME PRECIP INTO ANY GIVEN 12 HOUR FORECAST PERIOD IS INHERENTLY UNCERTAIN. SUSPECT THE SLOWER ECMWF/GEM SOLUTIONS ARE MORE IN LINE WITH REALITY. ALSO JUST WENT WITH A GENERIC RAIN OR SNOW MENTION GIVEN THE UNCERTAINTY SHOWN IN THE GEM ENSEMBLES WITH REGARDS TO SURFACE LOW TRACK. IF THE MEAN SOLUTION OF A LOW PASSING OVER OR JUST WEST OF KBUF VERIFIES...WE WOULD SEE SNOW CHANGE TO A WINTRY MIX THEN QUICKLY TO RAIN...THEN BACK TO SNOW AGAIN SATURDAY AS COLDER AIR MOVES BACK IN BEHIND THE SYSTEM. THIS IS ALL SPECULATION HOWEVER AT THIS TIME RANGE GIVEN THE MODEL UNCERTAINTY SHOWN ABOVE. FOLLOWING THIS SYSTEM...HEIGHTS QUICKLY RISE ACROSS THE GREAT LAKES AND OHIO VALLEY AS THE MEAN TROUGH RELOADS ACROSS THE WESTERN CONUS. TEMPS SHOULD MODERATE TO A LITTLE ABOVE AVERAGE BY THE END OF NEXT WEEKEND. SOME OF THE OPERATIONAL AND ENSEMBLE GUIDANCE SHOWS A WEAK SURFACE LOW AND MID LEVEL WAVE MOVING THROUGH THE GREAT LAKES ON DAY 7 SUNDAY...BUT GIVEN THE TIME RANGE AND WEAK NATURE OF THE SYSTEM WILL OPT TO KEEP THIS PERIOD DRY FOR NOW. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... MAIN CONCERN THROUGH THE TAF PERIOD IS AREAL EXTENT AND TIMING OF LOW STRATUS. THE LOW CLOUDS HAVE SCATTERED OUT ACROSS MUCH OF WESTERN AND CENTRAL NY AT MIDDAY. EXCEPTION IS ACROSS THE SOUTHERN TIER UP THROUGH THE FINGER LAKES WHERE MVFR CIGS ARE HOLDING TOUGH. RECENT TAMDAR ASCENT SOUNDINGS FROM CYYZ SHOW THE LOW LEVEL INVERSION HAS MIXED OUT...WHICH HAS ALLOWED SOME OF THE STRATUS TO ERODE. EXPECT VFR TO DOMINATE FOR MOST OF THE AREA THROUGH THIS EVENING. EXCEPTION WILL BE THE SOUTHERN TIER AROUND KJHW WHERE LOWER STRATUS IS NOW WORKING BACK IN WITH LOW END MVFR. THIS MAY LOWER FURTHER TO IFR BY LATE AFTERNOON GIVEN UPSTREAM TRENDS. TONIGHT EXPECT THE STRATUS TO FILL BACK IN AS THE LATEST NAM POINT SOUNDINGS SHOW A SUBSIDENCE INVERSION STRENGTHENING AND LOWERING OVERNIGHT. CIGS MAY DROP BELOW THE 2K FOOT THRESHOLD FOR EXTRA FUEL/ALTERNATE FOR A FEW HOURS LATER TONIGHT AND MONDAY MORNING AT KBUF-KIAG. IFR CIGS ARE EXPECTED TO CONTINUE THROUGH MUCH OF THE NIGHT ACROSS THE SOUTHERN TIER INCLUDING KJHW BEFORE SOME IMPROVEMENT MONDAY MORNING. THE LOW CLOUDS SHOULD SCATTER OUT TO VFR BY MID OR LATE MORNING MONDAY AS SOUTHERLY RETURN FLOW BEGINS. LOOKING FURTHER AHEAD...A STRONG COLD FRONT WILL CROSS THE REGION TUESDAY NIGHT WITH SEVERAL HOURS OF RAIN AND RESTRICTED CIGS/VSBY. STRONG WINDS ARE LIKELY ALONG AND BEHIND THIS FRONT FOLLOWED BY A 12-24 HOUR PERIOD OF LAKE EFFECT SNOW EAST OF LAKES ERIE AND ONTARIO FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH LOCALIZED VLIFR. LAKE SNOW WILL SHUT OFF BY THURSDAY AS HIGH PRESSURE BRINGS VFR TO THE REGION. ANOTHER SYSTEM MAY APPROACH BY FRIDAY WITH IFR CIGS AND MIXED PRECIPITATION. && .MARINE... AN UNUSUAL LONG STRETCH OF QUIET MARINE WEATHER IN MID WINTER WILL CONTINUE RIGHT THROUGH MONDAY NIGHT AS A RIDGE OF HIGH PRESSURE SLOWLY CROSSES THE EASTERN GREAT LAKES. WINDS WILL BE GENERALLY LESS THAN 10 KNOTS THROUGH MONDAY EVENING. LOOKING FURTHER AHEAD...A STRONG COLD FRONT IS FORECAST TO CROSS THE EASTERN GREAT LAKES TUESDAY NIGHT. SOUTHERLY WINDS WILL INCREASE AHEAD OF THIS COLD FRONT ON TUESDAY. LATE TUESDAY NIGHT WINDS WILL SHIFT TO THE SOUTHWEST OR WEST AND INCREASE DRAMATICALLY WITH STRONG LOW LEVEL COLD AIR ADVECTION AND A MODERATE PRESSURE GRADIENT. THERE IS A HIGH PROBABILITY OF GALE FORCE WINDS FROM LATER TUESDAY NIGHT THROUGH WEDNESDAY. 12Z/27 GFS RUN SHOWS THE SURFACE LOW BOTTOMING OUT AT ABOUT 973MB. THIS ALONG WITH PRESENCE OF 50 KNOT 925MB WINDS IN A STRONG CAA REGIME SUGGEST THAT GUSTS MAY APPROACH STORM FORCE DURING THIS PERIOD. THE STRONG WINDS WILL DIMINISH WEDNESDAY NIGHT AND ESPECIALLY THURSDAY AS A SURFACE HIGH BUILDS ACROSS THE EASTERN GREAT LAKES. && .CLIMATE... JANUARY IS ON ITS LAST LAP AND HAS BEEN A MOST INTERESTING MONTH. IT BEGAN WITH 4 COLD DAYS BUT THEN TURNED EXTREMELY MILD WITH THE NEXT 14 DAYS (5-18TH) AVERAGING 13 DEG ABOVE NORMAL. GROUND WAS BARE FROM 6-15TH. THEN...THE PATTERN CHANGED AND WE`VE JUST HAD 8 CONSEC COLD DAYS...AVERAGING 7 DEG BELOW NORMAL. THIS HAS FINALLY ESTABLISHED A SNOW COVER (ALTHOUGH THIN) AND ICED UP PONDS AND CREEKS. THE LAKE EFFECT MACHINE ALSO BECAME VERY ACTIVE...ALTHOUGH THE METRO AREAS ESCAPED ANYTHING SIGNIFICANT. IT APPEARS WE ARE ABOUT TO FLIP BACK TO A CHANGEABLE BUT OVERALL MILD PATTERN FOR THE NEXT WEEK OR SO. THE MONTH AS A WHOLE IS AVERAGING ABOUT 5 DEG WARMER THAN NORMAL WITH SNOWFALL AND PRECIP A BIT ON THE LIGHT SIDE. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...SFM NEAR TERM...SFM SHORT TERM...SFM LONG TERM...HITCHCOCK AVIATION...HITCHCOCK MARINE...HITCHCOCK CLIMATE...SFM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
235 PM EST SUN JAN 27 2008 .SYNOPSIS... THE UPCOMING WEEK WILL FEATURE VERY CHANGEABLE CONDITIONS BUT AVERAGE OUT ON THE MILD SIDE. HIGH PRESSURE OVER THE EASTERN LAKES WILL SLIDE SLOWLY EASTWARD TONIGHT AND MONDAY AND PROVIDE DRY WEATHER WITH INCREASING SUNSHINE MONDAY AFTERNOON. A SOUTHERLY FLOW OF MUCH WARMER AIR WILL THEN OVERSPREAD OUR REGION ON TUESDAY AHEAD OF A SHARP COLD FRONT WHICH WILL CROSS THE AREA LATE TUESDAY NIGHT. WINDY COLDER CONDITIONS WILL FOLLOW THE FRONT WEDNESDAY WITH SOME LIMITED LAKE EFFECT...BUT ANOTHER HIGH SHOULD PROVIDE A DRY MILDER DAY AGAIN ON THURSDAY. ANOTHER STORM WILL MOVE UP FROM THE OHIO VALLEY INTO THE LAKES ON FRIDAY AND PROVIDE ANOTHER SHOT OF RAIN OR MIXED PRECIPITATION. && .NEAR TERM /THROUGH TONIGHT/... MOST OF WESTERN AND CENTRAL NY BEING TREATED TO A BONUS DAY TODAY WITH PLENTY OF BRIGHT SUNSHINE AND LGT WINDS. THIS DESPITE A FAIRLY SATURATED LOWER ATMOSPHERE...BUT JUST ENOUGH SUBSIDENCE DEVELOPED BTWN UPPER WAVE OVER MICH AND DEEPENING COASTAL STORM OFF CAPE COD. WE DO EXPECT THE STRATUS TO REDEVELOP TONIGHT...AS WARMER AIR ADVECTS EASTWARD IN EARNEST WITH 850 MB TEMPS RISING SEVERAL DEGREES...AND STRENGTHENING THE INVERSION. WE ALSO HAVE A RESIDUAL AREA OF LOW CLOUD TO OUR WEST OVER SRN ONTARIO AND LOWER MICH...ASSOCIATED WITH UPPER IMPULSE WHICH SHOULD SHEAR OFF TO OUR SOUTHEAST LATER TONIGHT. TEMPS WILL BE A TOUGH CALL TONIGHT... DEPENDING ON HOW FAST WE CLOUD OVER AGAIN. WILL GO WITH GUID TEMPS MOSTLY L-M 20S BUT COULD GET COLDER IF WE STAY CLEAR LONGER. FOG COULD BE AN ISSUE IF THAT OCCURS TOO. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... WARM ADVECTION WILL BE STORY FOR FIRST 36 HOURS OF THIS PERIOD...AND AS IT WAS TODAY...MONDAY`S PROBLEM WILL BE EXTENT OF LOW CLOUD AND TIMING OF BURNOFF. INVERSION WILL BE STRENGTHENING DURING THE MORNING WITH 850 MB TEMPS RISING ABOVE ZERO SO HAVE TO FIGURE ON LOW CLOUD THEN...BUT GOOD SUBSIDENCE SHOULD MIX IT OUT DURING AFTERNOON SO WILL PLAY CLOUDS GIVING WAY TO SUN IN AFTERNOON. SHOULD BE A PLEASANT DAY WITH TEMPS NUDGING 40...BUT AGAIN CAN VARY FROM L-M 30S IF CLOUDS HANG TOUGH TO L-M 40S WITH MORE SUN. MODELS AT VARIANCE MON NT WITH NAM/ETA TOTALLY DRY WHILE GFS BRINGS A WEAKENING AREA OF SHOWERS ASSOC WITH MID LEVEL WARM FRONT INTO WEST AFTER MDNT. LATEST SREF JUST BARELY BRUSHES WEST AND CLIMO SUGGESTS LITTLE OR NONE WITH SOUTHERLY DOWNSLOPE...BUT WILL BRING LOW CHC SHOWERS IN WEST OF GENESEE RIVER LATE MON NT. SHOULD BE WARM ENOUGH FOR LIQUID IF THIS DOES INDEED OCCUR...ALTHOUGH WILL CARRY LOW CHC FZ RAIN BRIEFLY IN SRN TIER VALLEYS. TUES WILL BE A VERY MILD DAY WITH 850 MB TEMPS IN +6C RANGE. WE SHOULD HAVE A GOOD SOUTHERLY FLOW TO MIX THIS DOWN...BUT ALSO PLENTY OF CLOUD. WARMER NAM TEMPS LOOK MORE REASONABLE...M-U 40S EASILY...COULD EVEN BREAK 50 IN DOWNSLOPE AREAS OF LAKE PLAIN. BULK OF DAY WILL BE DRY...WILL JUST CARRY CHC POPS FOR SCATD SHOWERS. NEXT PLAYER WILL BE THE SHARP COLD FRONT PROGGED TO CROSS THE REGION TUES NT. WILL USE USUALLY RELIABLE GFS FOR TIMING WITH FROPA AT BUF AROUND 07Z AND ART BY 11Z. (NAM IS ABOUT 3 HRS FASTER). WILL CARRY HIGH LIKELY FOR SHOWERS AHEAD OF FRONT...A BRIEF CHANGE TO SNOW SHOWERS BEHIND IT. BIG STORY WILL BE THE WIND ON WED. VERY STRONG GRADIENT BETWEEN 974 MB LOW LIFTING UP ACROSS ONTARIO AND WESTERN QUEBEC AND 1024 RIDGE OVER OHIO VALLEY...WILL LIKELY SEE WIND ADVISORY CRITERIA MET WITH GUSTS UP NEAR 50 MPH...WILL HIGHLITE IN HWO. TEMPS WILL TUMBLE INTO 20S. THERE WILL BE LK EFFECT POTENTIAL...BUT WINDS MAY BE TOO STRONG INITIALLY WED MORNING...IT MAY SET UP LATER WED AND WED NT EAST OF THE LAKES ON A 270 FLOW...BUT IT WILL BE BRIEF AS RIDGE APPROACHES THURS. SEE LONG TERM BELOW. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A QUICK LOOK AT THE BASIC NORTHERN HEMISPHERIC FLOW INDICES SHOWS A PATTERN WHICH CANNOT SUSTAIN COLD AIR ACROSS THE GREAT LAKES FOR ANY LENGTH OF TIME. THE ARCTIC OSCILLATION /AO/ IS QUITE LITERALLY OFF THE CHARTS POSITIVE...AND THE NORTH ATLANTIC OSCILLATION /NAO/ IS RUNNING NEAR NEUTRAL. A POSITIVE AO IS INDICATIVE OF THE LOWEST HEIGHTS IN THE HEMISPHERE BEING LOCATED NEAR THE POLE...WITH ABOVE NORMAL HEIGHTS IN THE MID LATITUDES. THE AO IS FORECAST TO BECOME SOMEWHAT LESS POSITIVE THROUGH THE NEXT 10 DAYS...BUT REMAIN ON THE POSITIVE SIDE OF ZERO. THE NORTHERN HEMISPHERIC PATTERN THAT SUPPORTS A NEUTRAL OR POSITIVE AO AND NAO ALSO PREVENTS ANY HIGH LATITUDE BLOCKING FEATURES FROM DEVELOPING...AND THE LACK OF WHICH PREVENTS COLD AIR FROM REMAINING ACROSS THE GREAT LAKES FOR MORE THAN A FEW DAYS AT A TIME. THE MEAN MID LEVEL TROUGH WILL BE CENTERED OVER THE WESTERN CONUS THROUGH THE LONG TERM PERIOD...ALTHOUGH THERE WILL BE SEVERAL BRIEF TROUGH AMPLIFICATIONS INTO THE GREAT LAKES. LOOKING AT THE DETAILS...A STRONG COLD FRONT WILL CROSS THE EASTERN GREAT LAKES REGION TUESDAY NIGHT. BEHIND THE COLD FRONT...STRONG COLD AIR ADVECTION WILL BRING A RETURN TO MID WINTER CHILL. GFS/ECMWF ARE DIVERGING SOMEWHAT ON THE DETAILS OF THE SURFACE PATTERN EVOLUTION...WITH THE ECMWF DEEPER AND A LITTLE FARTHER WEST WITH THE SURFACE LOW...AND ALSO COLDER AT 850MB. ECMWF WOULD SUGGEST MORE OF A SOUTHWEST FLOW AND LAKE EFFECT CHANCES NORTHEAST OF LAKES ERIE AND ONTARIO. GFS IS NOT AS COLD AT 850MB AND NOT AS AMPLIFIED...WHICH WOULD SUPPORT MORE OF A WESTERLY FLOW WEDNESDAY AND LAKE EFFECT IN THE MORE TRADITIONAL SNOWBELTS. GIVEN THE LACK OF MODEL CONSISTENCY IN THE DETAILS AND INHERENT UNCERTAINTY AT THIS TIME RANGE...IT REMAINS TOO EARLY TO BE SPECIFIC ON EXACT LOCATION/INTENSITY...BUT THIS COULD BE ANOTHER STRONG LAKE EFFECT SNOW EVENT GIVEN THE LARGE SCALE PATTERN AND VERY FAVORABLE TEMPERATURES ALOFT. LAKE EFFECT SHOULD SHUT OFF BY THURSDAY AFTERNOON AS A RIDGE OF HIGH PRESSURE BUILDS ACROSS THE EASTERN LAKES. GFS AND ECMWF ARE COMING CLOSER TOGETHER IN SHOWING A DEEP SURFACE LOW LIFTING NORTH ALONG THE LOWER OHIO VALLEY TO THE EASTERN LAKES ON FRIDAY WITH ENOUGH WARM ADVECTION TO BRING A MIX OF PRECIP TYPES FROM FRIDAY MORNING THROUGH FRIDAY EVENING. WILL BUMP TEMPS UP A BIT FOR FRIDAY HIGHS AND INTRODUCE MIXED PRECIP DURING FRIDAY...CHANGING BACK TO SNOW AFTER 00Z SAT. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... MAIN CONCERN THROUGH THE TAF PERIOD IS AREAL EXTENT AND TIMING OF LOW STRATUS. THE LOW CLOUDS HAVE SCATTERED OUT ACROSS MUCH OF WESTERN AND CENTRAL NY AT MIDDAY. EXCEPTION IS ACROSS THE SOUTHERN TIER UP THROUGH THE FINGER LAKES WHERE MVFR CIGS ARE HOLDING TOUGH. RECENT TAMDAR ASCENT SOUNDINGS FROM CYYZ SHOW THE LOW LEVEL INVERSION HAS MIXED OUT...WHICH HAS ALLOWED SOME OF THE STRATUS TO ERODE. EXPECT VFR TO DOMINATE FOR MOST OF THE AREA THROUGH THIS EVENING. EXCEPTION WILL BE THE SOUTHERN TIER AROUND KJHW WHERE LOWER STRATUS IS NOW WORKING BACK IN WITH LOW END MVFR. THIS MAY LOWER FURTHER TO IFR BY LATE AFTERNOON GIVEN UPSTREAM TRENDS. TONIGHT EXPECT THE STRATUS TO FILL BACK IN AS THE LATEST NAM POINT SOUNDINGS SHOW A SUBSIDENCE INVERSION STRENGTHENING AND LOWERING OVERNIGHT. CIGS MAY DROP BELOW THE 2K FOOT THRESHOLD FOR EXTRA FUEL/ALTERNATE FOR A FEW HOURS LATER TONIGHT AND MONDAY MORNING AT KBUF-KIAG. IFR CIGS ARE EXPECTED TO CONTINUE THROUGH MUCH OF THE NIGHT ACROSS THE SOUTHERN TIER INCLUDING KJHW BEFORE SOME IMPROVEMENT MONDAY MORNING. THE LOW CLOUDS SHOULD SCATTER OUT TO VFR BY MID OR LATE MORNING MONDAY AS SOUTHERLY RETURN FLOW BEGINS. LOOKING FURTHER AHEAD...A STRONG COLD FRONT WILL CROSS THE REGION TUESDAY NIGHT WITH SEVERAL HOURS OF RAIN AND RESTRICTED CIGS/VSBY. STRONG WINDS ARE LIKELY ALONG AND BEHIND THIS FRONT FOLLOWED BY A 12-24 HOUR PERIOD OF LAKE EFFECT SNOW EAST OF LAKES ERIE AND ONTARIO FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH LOCALIZED VLIFR. LAKE SNOW WILL SHUT OFF BY THURSDAY AS HIGH PRESSURE BRINGS VFR TO THE REGION. ANOTHER SYSTEM MAY APPROACH BY FRIDAY WITH IFR CIGS AND MIXED PRECIPITATION. && .MARINE... NO MARINE ISSUES IN THE SHORT TERM. WINDS WILL REMAIN BELOW 15 KNOTS RIGHT THROUGH MONDAY. LOOKING FURTHER AHEAD...A STRONG COLD FRONT IS FORECAST TO CROSS THE EASTERN GREAT LAKES TUESDAY NIGHT. SOUTHERLY WINDS WILL INCREASE AHEAD OF THIS COLD FRONT MONDAY NIGHT AND TUESDAY. TUESDAY NIGHT WINDS WILL SHIFT TO THE SOUTHWEST OR WEST AND INCREASE DRAMATICALLY WITH STRONG LOW LEVEL COLD AIR ADVECTION AND A MODERATE PRESSURE GRADIENT. GALE FORCE WINDS ARE POSSIBLE FROM LATER TUESDAY NIGHT THROUGH WEDNESDAY...AND THERE IS ENOUGH MODEL CONSISTENCY AND FORECAST CONFIDENCE TO NOW INCLUDE GALE FORCE WINDS IN THE GRIDS/GLFLO. && .CLIMATE... JANUARY IS ON ITS LAST LAP AND HAS BEEN A MOST INTERESTING MONTH. IT BEGAN WITH 4 COLD DAYS BUT THEN TURNED EXTREMELY MILD WITH THE NEXT 14 DAYS (5-18TH) AVERAGING 13 DEG ABOVE NORMAL. GROUND WAS BARE FROM 6-15TH. THEN...THE PATTERN CHANGED AND WE`VE JUST HAD 8 CONSEC COLD DAYS...AVERAGING 7 DEG BELOW NORMAL. THIS HAS FINALLY ESTABLISHED A SNOW COVER (ALTHOUGH THIN) AND ICED UP PONDS AND CREEKS. THE LAKE EFFECT MACHINE ALSO BECAME VERY ACTIVE...ALTHOUGH THE METRO AREAS ESCAPED ANYTHING SIGNIFICANT. IT APPEARS WE ARE ABOUT TO FLIP BACK TO A CHANGEABLE BUT OVERALL MILD PATTERN FOR THE NEXT WEEK OR SO. THE MONTH AS A WHOLE IS AVERAGING ABOUT 5 DEG WARMER THAN NORMAL WITH SNOWFALL AND PRECIP A BIT ON THE LIGHT SIDE. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...SFM NEAR TERM...SFM SHORT TERM...SFM LONG TERM...HITCHCOCK/WCH AVIATION...HITCHCOCK MARINE...HITCHCOCK/WCH CLIMATE...SFM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1218 PM EST SUN JAN 27 2008 .SYNOPSIS... HIGH PRESSURE WILL GRADUALLY BUILD EASTWARD THIS AFTERNOON WITH A MIX OF SUN AND CLOUDS. THE CLOUDS WILL THICKEN UP AGAIN TONGHT BUT SUNSHINE SHOULD INCREASE AGAIN ON MONDAY WITH TEMPERATURES MOVING ABOVE FREEZING FOR THE FIRST TIME IN OVER A WEEK. A SOUTHERLY FLOW OF EVEN WARMER AIR WILL OVERSPREAD THE AREA TUESDAY WITH RAIN SHOWERS SPREADING EAST AHEAD OF A SHARP COLD FRONT WHICH WILL CROSS THE REGION TUESDAY NIGHT. MUCH COLDER AIR WILL SWEEP IN BEHIND THE FRONT WEDNESDAY WITH LAKE EFFECT EAST OF THE LAKES. ANOTHER MODERATING TREND WILL START ON THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SURPRISINGLY...SKIES HAVE OPENED UP NICELY ACROSS MUCH OF OUR REGION AS OF 16Z DESPITE NEARLY SATURATED 12Z BUF RAOB. THIS MAY BE DUE TO SUBSIDENCE BETWEEN DEEPENING STORM OFF THE COAST AND WEAK UPPER LEVEL FEATURE OVER MICHIGAN. IN ANY CASE...EXPECT SKIES TO FILL IN SOMEWHAT DURING THE AFTERNOON AS WE GET A BIT OF MIXING...BUT WILL TWEAK SKY GRIDS TO GO WITH SOME SUNSHINE AND BUMP TEMPS UP A FEW GE THIS AFTERNOON. WILL RETAIN MORE CLOUDINESS ACROSS SRN TIER. NO OTHER CHANGES. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... WARM ADVECTION ALOFT WILL STRENGTHEN INVERSION TONIGHT AND EARLY MONDAY KEEPING/RETURNING PLENTY OF LOW CLOUD COVER. ONCE RIDGE AXIS SLIDES EAST OF THE AREA MONDAY...THERE WILL BE ENOUGH MIXING TO ALLOW FOR A DECENT AMOUNT OF SUNSHINE ESPECIALLY DURING THE AFTERNOON. TEMPERATURES ON MONDAY WILL BE DEPENDENT ON AMOUNT OF SUNSHINE. BELIEVE THERE WILL BE ENOUGH SUNSHINE TO GET MOST AREAS INTO THE UPPER 30S TO LOWER 40S. SOUTHERLY FLOW WILL STRENGTHEN MONDAY NIGHT AND TUESDAY AHEAD OF APPROACHING COLD FRONT. WEAK SURFACE WARM FRONT WILL CROSS THE AREA LATE MONDAY NIGHT OR EARLY TUESDAY WITH THE CHANCE FOR SOME PRECIPITATION TO BREAK OUT. FOR THE MOST PART...CRITICAL TEMPERATURES WOULD SUGGEST IF PRECIPITATION DOES OCCUR IT SHOULD BE MAINLY LIQUID...BUT A FEW OF THE COLDER SOUTHERN TIER VALLEYS COULD SEE SOME LIGHT FREEZING RAIN AT ONSET. AREA WILL BE IN THE WARM SECTOR TUESDAY. THEREFORE...CAN NOT RULE OUT A FEW INSTABILITY SHOWERS DURING THE DAY. TEMPERATURES LOOK TO BE NICE AND MILD WITH MOST AREAS CLIMBING INTO THE MID AND UPPER 40S...WOULD NOT EVEN RULE OUT A FEW 50S WITH SOME SUNSHINE AS 850 MB TEMPERATURES WARM TO NEAR PLUS 6C. COLD FRONT APPROACHES AND CROSSES THE AREA TUESDAY NIGHT. GOOD LIKELIHOOD FOR RAIN SHOWERS ALONG AND AHEAD OF THE BOUNDARY WITH A TRANSITION TO SNOW SHOWERS BEHIND THE FRONTAL PASSAGE LATE TUESDAY NIGHT WITH RATHER WINDY CONDITIONS DEVELOPING BEFORE WEDNESDAY MORNING. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A QUICK LOOK AT THE BASIC NORTHERN HEMISPHERIC FLOW INDICES SHOWS A PATTERN WHICH CANNOT SUSTAIN COLD AIR ACROSS THE GREAT LAKES FOR ANY LENGTH OF TIME. THE ARCTIC OSCILLATION /AO/ IS QUITE LITERALLY OFF THE CHARTS POSITIVE...AND THE NORTH ATLANTIC OSCILLATION /NAO/ IS RUNNING NEAR NEUTRAL. A POSITIVE AO IS INDICATIVE OF THE LOWEST HEIGHTS IN THE HEMISPHERE BEING LOCATED NEAR THE POLE...WITH ABOVE NORMAL HEIGHTS IN THE MID LATITUDES. THE AO IS FORECAST TO BECOME SOMEWHAT LESS POSITIVE THROUGH THE NEXT 10 DAYS...BUT REMAIN ON THE POSITIVE SIDE OF ZERO. THE NORTHERN HEMISPHERIC PATTERN THAT SUPPORTS A NEUTRAL OR POSITIVE AO AND NAO ALSO PREVENTS ANY HIGH LATITUDE BLOCKING FEATURES FROM DEVELOPING...AND THE LACK OF WHICH PREVENTS COLD AIR FROM REMAINING ACROSS THE GREAT LAKES FOR MORE THAN A FEW DAYS AT A TIME. THE MEAN MID LEVEL TROUGH WILL BE CENTERED OVER THE WESTERN CONUS THROUGH THE LONG TERM PERIOD...ALTHOUGH THERE WILL BE SEVERAL BRIEF TROUGH AMPLIFICATIONS INTO THE GREAT LAKES. LOOKING AT THE DETAILS...A STRONG COLD FRONT WILL CROSS THE EASTERN GREAT LAKES REGION TUESDAY NIGHT. BEHIND THE COLD FRONT...STRONG COLD AIR ADVECTION WILL BRING A RETURN TO MID WINTER CHILL. GFS/ECMWF ARE DIVERGING SOMEWHAT ON THE DETAILS OF THE SURFACE PATTERN EVOLUTION...WITH THE ECMWF DEEPER AND A LITTLE FARTHER WEST WITH THE SURFACE LOW...AND ALSO COLDER AT 850MB. ECMWF WOULD SUGGEST MORE OF A SOUTHWEST FLOW AND LAKE EFFECT CHANCES NORTHEAST OF LAKES ERIE AND ONTARIO. GFS IS NOT AS COLD AT 850MB AND NOT AS AMPLIFIED...WHICH WOULD SUPPORT MORE OF A WESTERLY FLOW WEDNESDAY AND LAKE EFFECT IN THE MORE TRADITIONAL SNOWBELTS. GIVEN THE LACK OF MODEL CONSISTENCY IN THE DETAILS AND INHERENT UNCERTAINTY AT THIS TIME RANGE...IT REMAINS TOO EARLY TO BE SPECIFIC ON EXACT LOCATION/INTENSITY...BUT THIS COULD BE ANOTHER STRONG LAKE EFFECT SNOW EVENT GIVEN THE LARGE SCALE PATTERN AND VERY FAVORABLE TEMPERATURES ALOFT. LAKE EFFECT SHOULD SHUT OFF BY THURSDAY AFTERNOON AS A RIDGE OF HIGH PRESSURE BUILDS ACROSS THE EASTERN LAKES. GFS AND ECMWF ARE COMING CLOSER TOGETHER IN SHOWING A DEEP SURFACE LOW LIFTING NORTH ALONG THE LOWER OHIO VALLEY TO THE EASTERN LAKES ON FRIDAY WITH ENOUGH WARM ADVECTION TO BRING A MIX OF PRECIP TYPES FROM FRIDAY MORNING THROUGH FRIDAY EVENING. WILL BUMP TEMPS UP A BIT FOR FRIDAY HIGHS AND INTRODUCE MIXED PRECIP DURING FRIDAY...CHANGING BACK TO SNOW AFTER 00Z SAT. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... MAIN CONCERN THROUGH THE TAF PERIOD IS AREAL EXTENT AND TIMING OF LOW STRATUS. THE LOW CLOUDS HAVE SCATTERED OUT ACROSS MUCH OF WESTERN AND CENTRAL NY AT MIDDAY. EXCEPTION IS ACROSS THE SOUTHERN TIER UP THROUGH THE FINGER LAKES WHERE MVFR CIGS ARE HOLDING TOUGH. RECENT TAMDAR ASCENT SOUNDINGS FROM CYYZ SHOW THE LOW LEVEL INVERSION HAS MIXED OUT...WHICH HAS ALLOWED SOME OF THE STRATUS TO ERODE. EXPECT VFR TO DOMINATE FOR MOST OF THE AREA THROUGH THIS EVENING. EXCEPTION WILL BE THE SOUTHERN TIER AROUND KJHW WHERE LOWER STRATUS IS NOW WORKING BACK IN WITH LOW END MVFR. THIS MAY LOWER FURTHER TO IFR BY LATE AFTERNOON GIVEN UPSTREAM TRENDS. TONIGHT EXPECT THE STRATUS TO FILL BACK IN AS THE LATEST NAM POINT SOUNDINGS SHOW A SUBSIDENCE INVERSION STRENGTHENING AND LOWERING OVERNIGHT. CIGS MAY DROP BELOW THE 2K FOOT THRESHOLD FOR EXTRA FUEL/ALTERNATE FOR A FEW HOURS LATER TONIGHT AND MONDAY MORNING AT KBUF-KIAG. IFR CIGS ARE EXPECTED TO CONTINUE THROUGH MUCH OF THE NIGHT ACROSS THE SOUTHERN TIER INCLUDING KJHW BEFORE SOME IMPROVEMENT MONDAY MORNING. THE LOW CLOUDS SHOULD SCATTER OUT TO VFR BY MID OR LATE MORNING MONDAY AS SOUTHERLY RETURN FLOW BEGINS. LOOKING FURTHER AHEAD...A STRONG COLD FRONT WILL CROSS THE REGION TUESDAY NIGHT WITH SEVERAL HOURS OF RAIN AND RESTRICTED CIGS/VSBY. STRONG WINDS ARE LIKELY ALONG AND BEHIND THIS FRONT FOLLOWED BY A 12-24 HOUR PERIOD OF LAKE EFFECT SNOW EAST OF LAKES ERIE AND ONTARIO FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH LOCALIZED VLIFR. LAKE SNOW WILL SHUT OFF BY THURSDAY AS HIGH PRESSURE BRINGS VFR TO THE REGION. ANOTHER SYSTEM MAY APPROACH BY FRIDAY WITH IFR CIGS AND MIXED PRECIPITATION. && .MARINE... NO MARINE ISSUES IN THE SHORT TERM. WINDS WILL REMAIN BELOW 15 KNOTS RIGHT THROUGH MONDAY. LOOKING FURTHER AHEAD...A STRONG COLD FRONT IS FORECAST TO CROSS THE EASTERN GREAT LAKES TUESDAY NIGHT. SOUTHERLY WINDS WILL INCREASE AHEAD OF THIS COLD FRONT MONDAY NIGHT AND TUESDAY. TUESDAY NIGHT WINDS WILL SHIFT TO THE SOUTHWEST OR WEST AND INCREASE DRAMATICALLY WITH STRONG LOW LEVEL COLD AIR ADVECTION AND A MODERATE PRESSURE GRADIENT. GALE FORCE WINDS ARE POSSIBLE FROM LATER TUESDAY NIGHT THROUGH WEDNESDAY...AND THERE IS ENOUGH MODEL CONSISTENCY AND FORECAST CONFIDENCE TO NOW INCLUDE GALE FORCE WINDS IN THE GRIDS/GLFLO. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...TMA NEAR TERM...SFM SHORT TERM...TMA LONG TERM...HITCHCOCK/WCH AVIATION...HITCHCOCK MARINE...HITCHCOCK/WCH
AREA FORECAST DISCUSSION
NWS PORTLAND OR
241 AM PST SAT JAN 26 2008 .SYNOPSIS...MOISTURE FROM A LOW IN CALIFORNIA WILL SPREAD NORTHWARD TODAY ACROSS NORTHWEST OREGON AND SOUTHWEST WASHINGTON TODAY...THEN MERGE WITH A COLD FRONT DROPPING OUT OF THE GULF OF ALASKA LATE TODAY AND TONIGHT. THIS WILL BRING INCREASING RAIN TO THE VALLEYS AND SNOW TO THE MOUNTAINS...EXCEPT SOME FREEZING RAIN OR SNOW IS EXPECTED INLAND THIS MORNING BEFORE A SLIGHT MODERATION TAKES PLACE THIS AFTERNOON. THE FREEZING RAIN AND SNOW MAY PERSIST IN THE COLUMBIA RIVER GORGE INTO TONIGHT. A COLD AIR MASS WITH ABUNDANT SHOWERS AND VERY LOW SNOW LEVELS WILL SPREAD IN BEHIND THE FRONT SUNDAY THROUGH MONDAY WITH HEAVY SNOW IN THE CASCADES...AND POSSIBLY IN THE COAST RANGE AND THE CASCADE FOOTHILLS. SEVERAL MORE SYSTEMS ARE EXPECTED NEXT WEEK WITH LOW SNOW LEVELS AT TIMES. && .SHORT TERM...THE 00Z SALEM SOUNDING...PDX ACARS SOUNDINGS...AND THE KPTV TOWER TEMPERATURES ARE SHOWING WARM AIR ALOFT MOVING INTO SOUTHWEST WASHINGTON AND NORTHWEST OREGON OVERNIGHT. VALLEY TEMPERATURES WERE BELOW FREEZING NEARLY EVERYWHERE. THIS WILL SET UP A SITUATION THAT AS MOISTURE SPREADS NORTH FROM A LOW OFF CALIFORNIA THIS MORNING THAT THE PRECIPITATION IN THE VALLEYS WILL LIKELY EITHER START AS FREEZING RAIN OR SLEET. THE FREEZING RAIN SCENARIO IS ENHANCED SINCE EXPOSED SURFACES AND THE GROUND HAVE BEEN EXPOSED TO A CONSIDERABLE AMOUNT OF BELOW FREEZING AIR FOR SEVERAL DAYS NOW. THE KPTV TOWER TEMPS INDICATE THE DEPTH OF THE COLD AIR IS AROUND 1200 FEET AND THIS COULD BE ENOUGH DEPTH FOR SNOW AT THE ONSET. THE INITIAL PRECIPITATION THIS MORNING SHOULD BE RATHER LIGHT...THEN IT PICKS UP LATER THIS MORNING AND THIS AFTERNOON. AS THE MOISTURE INCREASES THIS AFTERNOON...THE LOW LEVEL WIND FLOW BECOMES MORE SOUTHERLY AND HELPS MODERATE THE LOW LEVELS TO RAIN. WILL STAY WITH A SPECIAL STATEMENT FOR THIS IN THE VALLEYS FOR NOW DUE TO UNCERTAINTY OF HOW MUCH MIXED PRECIPITATION OCCURS BEFORE CHANGING TO RAIN...BUT A WINTER WEATHER ADVISORY FOR SOME AREAS IS NOT OUT OF THE QUESTION. IN THE GORGE AND THE UPPER HOOD RIVER VALLEY IT MAY TAKE UNTIL SOME TIME TONIGHT AT THE EARLIEST TO MIX OUT. DUE TO TEMPS IN THE LOWER 20S WILL ISSUE A WINTER STORM WARNING FOR SNOW AND FREEZING RAIN OUT THROUGH THIS EVENING. IN THE CASCADES...THE PRECIPITATION INCREASES THIS AFTERNOON AND IS MOSTLY SNOW...SO WENT WITH A HEAVY SNOW WARNING THERE. A COLD FRONT DROPS OUT OF THE GULF OF ALASKA LATE TODAY AND SPREADS THROUGH OUR FORECAST AREA TONIGHT. THIS IS PARTLY THE REASON FOR THE INCREASING SOUTHERLY FLOW...PLUS IT INTERACTS WITH THE MOISTURE FROM CALIFORNIA AND HELPS INCREASE THE PRECIPITATION THIS AFTERNOON AND TONIGHT. AS THE FRONT MOVES THROUGH...THIS WILL PROBABLY BE THE MECHANISM TO MIX OUT THE GORGE BRIEFLY LATER TONIGHT. A VERY COLD AIR MASS SPREADS IN BEHIND THE FRONT SUNDAY THROUGH MONDAY WITH RATHER SIGNIFICANT OROGRAPHIC ONSHORE FLOW AND SHOWERS. HAVE BUMPED POPS UP THROUGH MONDAY TO DEFINITE. SNOW LEVELS WILL APPROACH THE VALLEY FLOORS...AND ARE LOWEST SUNDAY NIGHT AND MONDAY. THE OROGRAPHICS PICK UP LATER SUNDAY AND CONTINUE THROUGH MONDAY. FOR THIS REASON HAVE LEFT THE HEAVY SNOW WARNING FOR THE CASCADES UP THROUGH MONDAY. COULD POSSIBLY NEED A SNOW ADVISORY OR MORE FOR THE CASCADE FOOTHILLS AND COAST RANGE SUNDAY THROUGH MONDAY...BUT WILL LET A SPECIAL STATEMENT DEAL WITH THAT FOR NOW. ONLY MINOR CHANGE TO THE EXTENDED DISCUSSION BELOW WAS TO ADD MORE MIXED RAIN AND SNOW TO THE VALLEYS MONDAY NIGHT WITH THE NEXT COOL SYSTEM. TOLLESON .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... NO SIGNIFICANT CHANGES MADE TO THE EXTENDED FORECAST FOR THE AFTERNOON PACKAGE. A SYSTEM IS EXPECTED TO TRAVERSE THE GULF OF AK REGION AND MOVE INTO THE PAC NORTHWEST ON TUE MORNING. THIS SYSTEM WILL BE SIMILAR IN NATURE TO PREVIOUS ONES WITH SNOW LEVELS RISING SLIGHTLY IN THE OVER-RUNNING PORTION OF THE SYSTEM...THEN FALLING BACK DOWN BEHIND THE COLD FRONT. THICKNESS VALUES ARE SUCH THAT SNOW LEVELS SHOULD STAY GENERALLY ABOVE 1000 FEET THROUGHOUT THE EXTENDED...SAVE TUESDAY EVENING WHEN THE COLDEST PORTION OF THE UPPER TROUGH MOVES THROUGH. WHILE OROGRAPHIC FLOW IS FAR FROM IDEAL...THE NORTH OREGON AND SOUTH WASHINGTON CASCADES SHOULD SEE SIGNIFICANT SNOWFALL ON TUESDAY...CONTINUING INTO WED MORNING. DALTON && .AVIATION...VFR CONDITIONS EXPECTED THIS MORNING...LOWERING TO MVFR BY LATE THIS AFTERNOON. LOW PRES OVER N CALIF SPREADING MID AND HIGH CLOUDS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA THIS MORNING. THIS TREND WILL CONTINUE...WITH CLOUDS SLOWLY MOVING N...REACHING THE COLUMBIA RIVER AROUND 10Z. THIS BAND MAY PRODUCE AREAS OF VERY LIGHT FREEZING RAIN OVER THE INTERIOR THIS MORNING WITH JUST RAIN ON THE COAST. NOT SURE THAT MOISTURE WILL REACH THE GROUND GIVEN THE DRY MID LEVEL AIR IN PLACE. MODELS INDICATE THAT ANY FREEZING RAIN WOULD END AROUND 12-14Z IN KEUG AND AROUND 18Z AT KPDX. KPDX AND APPROACHES...VFR CONDITIONS EXPECTED THIS MORNING... LOWERING TO MVFR BY 22Z. VERY LIGHT FREEZING RAIN MAY DEVELOP 14Z-18Z THIS MORNING. CONFIDENCE ABOUT 20 PERCENT. STEADY RAIN WILL DEVELOP AFTER 18Z. && .MARINE...SEAS ARE JUST NOW FALLING BELOW 10 FT AND WILL DROP THE SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS WITH THE MORNING PACKAGE. HOWEVER...WILL HOIST THE SMALL CRAFT FOR WINDS AHEAD OF THE COLD FRONT THIS AFTERNOON THROUGH THIS EVENING. && .PQR WATCHES/WARNINGS/ADVISORIES... WA/OR...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR THIS MORNING AND THIS EVENING. SMALL CRAFT ADVISORY FOR WINDS FROM CAPE SHOALWATER TO FLORENCE THIS AFTERNOON THROUGH THIS EVENING. HEAVY SNOW WARNING SOUTH WASHINGTON AND NORTH AND CENTRAL OREGON CASCADES LATER THIS MORNING THROUGH MONDAY. WINTER STORM WARNING WESTERN COLUMBIA RIVER GORGE AND UPPER HOOD RIVER VALLEY LATER THIS MORNING THROUGH THIS EVENING. && .PRELIMINARY POINT POPS (PROBABILITY OF MEASURABLE PRECIPITATION) AST 8+999 PDX 8+888 SLE 8+888 EUG 8+888 $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS CHICAGO IL
403 AM CST MON JAN 28 2008 .DISCUSSION... 402 AM CST UPPER TROUGH DEEPENING ACROSS WESTERN NORTH AMERICA TODAY...WITH SERIES OF MINOR SHORT WAVES RIPPLING NORTHEAST ALONG PERIPHERY OF STRONG JET INTO MIDWEST AND NORTHERN GREAT LAKES. SURFACE PRESSURES CONTINUE TO FALL ACROSS THE PLAINS IN RESPONSE TO JET AND UPPER TROUGH...STRENGTHENING SOUTHERLY LOW LEVEL FLOW INTO FORECAST AREA AND DRAWING WARM AIR RAPIDLY NORTH. PROFILER NETWORK INDICATES 50-60 KNOT SOUTHWEST 850 HPA JET SPREADING FROM TEXAS PANHANDLE NORTHEAST INTO UPPER MISSISSIPPI VALLEY PROVIDING IMPRESSIVE WARM ADVECTION AND HIGH CLOUDINESS TO THE REGION... THOUGH REGIONAL RADAR MOSAIC INDICATES LITTLE ORGANIZED PRECIPITATION. 00Z RAOB ANALYSIS INDICATES WHY...WITH 15-20 DEGREE DEW POINT DEPRESSIONS IN 925-850 HPA LAYER IN LOW LEVEL JET SOURCE REGION. SHORT TERM MODEL GUIDANCE DOES INDICATE SATURATION WILL EVENTUALLY OCCUR ACROSS THE AREA LATER TODAY...BUT HAVE REMOVED MENTION OF SHOWERS FOR THIS MORNING. SOUTHERN CALIFORNIA SHORT WAVE LIFTS ACROSS REGION THIS EVENING WITH 850 HPA WARM FRONT PUSHING NORTHEAST OF AREA OVERNIGHT...THUS EXPECT SHOWER COVERAGE TO BE HIGHEST DURING EVENING...THEN DECREASE SOMEWHAT OVERNIGHT AS STRONGER FORCING MOVES NORTHEAST OF FORECAST AREA. BIGGER CHALLENGE PERHAPS TODAY AND TONIGHT ARE TEMPERATURES...WITH BATTLE BETWEEN STRONG LOW LEVEL THERMAL ADVECTION AND REMAINING SNOW COVER ACROSS ESPECIALLY FAR NORTHERN IL. LOW LEVEL PARCEL TRAJECTORIES AND MODEL FORECAST 950 HPA TEMPS INDICATE 50S POSSIBLE ACROSS SOUTHERN PARTS OF CWA AND HAVE GENERALLY GONE ABOVE GUIDANCE TEMPS THERE...THOUGH HAVE STAYED CLOSER TO GUIDANCE IN MID 40S FARTHER NORTH WHERE RECEDING SNOW COVER WILL HAVE SOME EFFECT. WITH SURFACE PRESSURE GRADIENT MAINTAINING STRONG SOUTH WINDS OVERNIGHT...APPEARS ALL MOS GUIDANCE MUCH TOO COOL WITH OVERNIGHT MINS. MAIN UPPER TROUGH PUSHES TOWARD AREA ON TUESDAY...WITH STRONG HEIGHT FALLS DEVELOPING ACROSS THE AREA DURING THE DAY. COMBINATION OF STRONG LOW LEVEL FRONTOGENESIS AND FAVORABLE LEFT EXIT REGION OF UPPER JET STREAK SUPPORT MODEL DEPICTIONS OF DEEP VERTICAL MOTION DURING THE PERIOD...WITH STEEPENING MID LEVEL LAPSE RATES AND LOW LEVEL MOIST AXIS AHEAD OF COLD FRONT INCREASING POTENTIAL FOR CONVECTION. WRF AND GFS BOTH DEPICT WEAK ELEVATED CAPE FOR PARCELS JUST BELOW 850 HPA TUESDAY MORNING THUS WILL MAINTAIN MENTION OF ISOLATED THUNDER. APPEARS FROPA WILL OCCUR BY MIDDAY AT ROCKFORD...DURING EARLY/MID AFTERNOON IN CHICAGO AND DURING THE MID/LATE AFTERNOON FOR INDIANA COUNTIES. MODELS CONTINUE TO DEPICT THICKNESS VALUES FALLING RAPIDLY WITH FAIRLY QUICK CHANGE FROM RAIN TO SNOW EXPECTED...AND WEST/NORTHWEST WINDS GUSTING 30 TO 40 MPH. POTENTIAL FOR AN INCH OR SO OF SNOW TUESDAY AFTERNOON/EVENING...THOUGH WINDS WILL KEEP IT FROM ACCUMULATING UNIFORMLY AND WILL MENTION BLOWING SNOW AS WELL. PRECIP TO TAPER OFF FROM WEST TO EAST DURING THE EVENING WITH SUBSIDENCE AND STRONG LOW LEVEL DRY ADVECTION ALLOWING DECREASING CLOUDS/CLEARING AS ARCTIC AIR POURS IN. WITH TEMPS CRASHING INTO SINGLE DIGITS AND EVEN SOME SUBZERO READINGS...GUSTY WINDS WILL LIKELY SEND WIND CHILL READINGS INTO -20 TO -25 RANGE ACROSS NORTHERN IL BY EARLY WEDNESDAY MORNING. STORM EXITS QUICKLY TO THE EAST BY WEDNESDAY WITH WEAK SURFACE RIDGE MOVING ACROSS THE AREA AND ALLOWING WINDS TO DIMINISH THOUGH WITH COLD TEMPS CONTINUING BY AFTERNOON. MODELS REMAIN QUITE SIMILAR IN DIGGING ANOTHER UPPER TROUGH ACROSS THE WEST HOWEVER...RESULTING IN QUICK RETURN OF LOW LEVEL WARM ADVECTION ACROSS PLAINS TO OUR WEST WITH AREA OF LIGHT WAA SNOW INDICATED PERHAPS AS FAR EAST AS NORTHWEST IL/SOUTHERN WI WEDNESDAY NIGHT. LONGER RANGE GUIDANCE CONTINUES TO DEPICT STRONGER STORM SYSTEM THURSDAY/FRIDAY...THOUGH SIGNIFICANT DIFFERENCES CONTINUE WITH RESPECT TO TRACK OF SURFACE LOW. ECMWF CONTINUES TO BE FARTHEST WEST WITH LOW LIFTING FROM SOUTHERN PLAINS TO SOUTHERN LAKE MICHIGAN...00Z GFS CONTINUES TO FAVOR A TRACK FARTHER EAST UP THE OHIO RIVER...WHILE THE GEM IS IN BETWEEN WITH A TRACK MORE ACROSS OHIO. AT THIS DISTANCE WILL MAINTAIN CHANCE FOR SNOW ACROSS CWA THURSDAY NIGHT THROUGH FRIDAY AND CONTINUE TO HIGHLIGHT POTENTIAL FOR WINTER STORM SOMEWHERE NEARBY IN HAZARDOUS WEATHER OUTLOOK. RATZER && .AVIATION... 0600 UTC TAFS THERE WILL BE AREAS OF FOG TONIGHT AS THE WARMER AIR MOVES ACROSS THE SNOW. AN INVERSION IS SEEN ON THE ACARS DATA AT 0325 UTC FROM SURFACE TO 2260 FT. THE WIND HAS DECEASED THIS EVENING AS A RESULT OF THE STABLE BOUNDARY LAYER SETTING UP. SATELLITE SHOWS NO LOW CLOUDS...JUST CIRRUS AT 25000 FEET. WILL HAVE A FORECAST OF SOUTH WIND 18 KNOTS WITH GUSTS TO 30 KNOTS MONDAY AFTERNOON. WE EXPECT SOME 5000 FT CLOUDS TO MOVE IN AHEAD OF THE RAIN MONDAY NIGHT. THEN AROUND 21 UTC WE EXPECT LIGHT RAIN TO MOVE INTO THE AREA FROM ROCKFORD TO CHICAGO. THE FORECAST SOUNDING SHOW A LARGE INCREASE IN WIND FROM THE SURFACE TO 1500 FEET BY MONDAY AFTERNOON. THE 925 MB LEVEL SHOWS 60 KNOT WIND OVER NORTHERN ILLINOIS BY 00 UTC TUESDAY. WILL ADD THE LOW LEVEL WIND SHEAR TO THE FORECAST UP TO 1500 FT FROM 2100 UTC THROUGH 06 UTC. && .MARINE... 315 AM CST A VERY ACTIVE MARINE PERIOD IN TERMS OF WINDS IS IN STORE FROM TODAY THROUGH WEDNESDAY. SOUTHERLY SURFACE PRESSURE GRADIENT WILL CONTINUE TO STRENGTHEN THIS MORNING. WINDS HAVE BEEN A BIT SLOW TO RESPONSE DUE TO WARM ADVECTION OVER COLD LAKE WATERS...BUT TOWARD MIDDAY EXPECTING SOUTH GALES TO BECOME PREVALENT. IT APPEARS AS THROUGH STRONGEST WINDS TO AROUND 40 KNOTS WILL OCCUR IN THE 21Z-06Z TIME FRAME...WITH WINDS SLOWLY DECREASING OVERNIGHT AND INTO TUESDAY MORNING. BY TUESDAY MORNING...A TROUGH OF LOW PRESSURE WILL BE APPROACHING LAKE MICHIGAN WITH A WEAKENING SFC PRESSURE GRADIENT THAT SHOULD ALLOW SOUTHWEST WINDS TO DROP INTO THE 15 TO 25 KNOT RANGE. THIS LULL IN WIND SPEEDS WILL BE SHORT LIVED AS ANOTHER LOW PRESSURE AREA DEVELOPS ACROSS THE CENTRAL PLAINS AND APPROACHES LAKE MICHIGAN TUESDAY AFTERNOON. AN ARCTIC AIR MASS WILL SPREAD OVER THE REGION IN THE WAKE OF THIS LOW PRESSURE ON TUESDAY EVENING...AND ANOTHER PERIOD OF GALES IS EXPECTED LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT FROM THE WEST NORTHWEST. SFC GRADIENT SHOULD SUPPORT CONTINUED GALES INTO WEDNESDAY MORNING ACROSS THE NORTH HALF OF THE LAKE. A RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING LOW PRESSURE AREA LATE WEDNESDAY...ALLOWING FOR WINDS AND WAVES TO SUBSIDE. LATE WEEK PERIOD SHOULD FEATURE EAST NORTHEAST WINDS AS LOW PRESSURE DEVELOPS ACROSS THE SOUTHERN PLAINS AND AS THE RIDGE OF HIGH PRESSURE DEPARTS TO THE EAST. IN TERMS OF HEADLINES...WILL EXTEND GALE WARNING FOR NEARSHORE AND OPEN WATERS TO COVER THE EXPECTED SOUTH GALES TODAY/TONIGHT...AND THEN WEST GALES LATE TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY. MARSILI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING FROM 9 AM THIS MORNING TO 6 AM CST WEDNESDAY FOR LMZ740>745-777-779. && $$ WFO LOT
AREA FORECAST DISCUSSION
NWS CHICAGO IL
316 AM CST MON JAN 28 2008 .DISCUSSION... 307 PM CST WITH HIGH PRESSURE EDGING EAST OVERNIGHT...SOUTH FLOW SHUD INCREASE OVERNIGHT. MODELS INDICATING SHARP INVERSION OVER SNOWPACK BUT WARMING WORKING DOWN TO SFC OVERNIGHT SO THAT AFTER INITIAL RADIATIVE DROP THIS EVENING...TEMPS SHUD PICK UP AND RISE OVERNIGHT TO ABV FRZG BY MRNG AND CONTINUE CLIMBING THRU MONDAY AS LOW LVL JET INCREASES TO 40KTS EARLY THEN TO NEAR 60KTS BY MIDDAY. VERY WK SHORT WAVE RIDING UP FROM THE DESERT SW TNGT FINDING SOME MID LVL CONVERGENCE OVER THE MS VLY ON MONDAY IN THE THERMAL RIDGE SPEARHEADED BY THIS JET. MAY HAVE A FEW SHOWERS DEVELOP AHEAD OF THIS WAVE IN THE LATE MRNG AND EARLY AFTN WITH LIGHT PCPN AMNTS ...CONSIDERING DRY LOW LVLS. ALSO LIKELY TO BE PRETTY WINDY IN THE AFTN AND EVENING HOURS MON AND CUD BE NEAR ADVISORY CRITERIA BUT PROBLY JUST UNDER. INITIAL SHOT PASSES IN AFTN AND LIKELY TO BE DRY GOING INTO EVENING WHEN ANOTHER PASSING MID LVL WAVE MAY AGAIN PROMPT SHOWER DEVELOPMENT. ASSUMING SOME WETTING OF LOWER LVLS FROM THE FIRST SHOT...RAIN CUD BE MORE CERTAIN IN THE EVENING WITH AN ODD CHANCE OF A RUMBLE OF THUNDER. WINDS SHUD START TO WEAKEN A BIT AFTER MIDNIGHT AS THE ASSOCIATED SFC LOW COMES SWINGING ACROSS THE MS VLY TOWARD TUES MRNG. THIS STRONG FRONT WILL SWING THRU ERN IL AND NW INDY IN THE AFTN CHANGING ANY RAIN TO SNOW. SNOW AMOUNTS CUD BE UP TO AND INCH OR TWO WHICH MAY GO UNDETECTED CONSIDERING WINDS WILL LIKELY PICK UP TO GALE FORCE OR BETTER. FUTURE CHOICES WILL BE FOR HIGH WIND WARNING OR WIND ADVISORY OR BLOWING SNOW ADVISORY OR POSSIBLY WINTER STORM WARNING FOR NEAR BLIZZARD CONDITIONS IF ENUF SNOW CAUSES VSBY TO DROP TO 1/4 MILE OR LESS. MODELS HAVE BEEN SLOWING FRONT MOVEMENT FROM PREVIOUS RUNS AND TIMING OF THIS MAY BE PUSHED BACK...SO NO HEADLINES AS YET...BUT OUTLOOKS WILL CARRY A CAVEAT FOR TUESDAY INTO TUESDAY NIGHT. THIS COLD BLAST WILL ALSO BE RESPONSIBLE FOR FALLING DAYTIME TEMPS ON TUESDAY...BACK INTO THE SINGLE DIGITS FOR MOST AREAS WED MORNING. WIND CHILLS WILL AGAIN BE A CONCERN IF NOT A HEADLINE. WINDS SLACK QUICKLY WED AS HIGH PRESSURE BUILDS IN FOR MIDWEEK. WARMING RETURNS TO THE 20S FOR HIGHS WED AND AGAIN THURSDAY AS UPR FLOW BACKS TO THE SW AGAIN. THIS HAPPENS AS ANOTHER LOW PRESS SYSTEM DEEPENS IN THE SRN PLAINS. THIS MAY PLAY A MAJOR ROLE AS A HEAVY SNOW MAKER THURSDAY INTO FRIDAY OVER THE MIDWEST. HIGH PRESSURE SHUD FOLLOW THIS SYSTEM FOR THE WEEKEND AND OFFER SOME QUIET TIME. RLB && .AVIATION... 0600 UTC TAFS THERE WILL BE AREAS OF FOG TONIGHT AS THE WARMER AIR MOVES ACROSS THE SNOW. AN INVERSION IS SEEN ON THE ACARS DATA AT 0325 UTC FROM SURFACE TO 2260 FT. THE WIND HAS DECEASED THIS EVENING AS A RESULT OF THE STABLE BOUNDARY LAYER SETTING UP. SATELLITE SHOWS NO LOW CLOUDS...JUST CIRRUS AT 25000 FEET. WILL HAVE A FORECAST OF SOUTH WIND 18 KNOTS WITH GUSTS TO 30 KNOTS MONDAY AFTERNOON. WE EXPECT SOME 5000 FT CLOUDS TO MOVE IN AHEAD OF THE RAIN MONDAY NIGHT. THEN AROUND 21 UTC WE EXPECT LIGHT RAIN TO MOVE INTO THE AREA FROM ROCKFORD TO CHICAGO. THE FORECAST SOUNDING SHOW A LARGE INCREASE IN WIND FROM THE SURFACE TO 1500 FEET BY MONDAY AFTERNOON. THE 925 MB LEVEL SHOWS 60 KNOT WIND OVER NORTHERN ILLINOIS BY 00 UTC TUESDAY. WILL ADD THE LOW LEVEL WIND SHEAR TO THE FORECAST UP TO 1500 FT FROM 2100 UTC THROUGH 06 UTC. && .MARINE... 315 AM CST A VERY ACTIVE MARINE PERIOD IN TERMS OF WINDS IS IN STORE FROM TODAY THROUGH WEDNESDAY. SOUTHERLY SURFACE PRESSURE GRADIENT WILL CONTINUE TO STRENGTHEN THIS MORNING. WINDS HAVE BEEN A BIT SLOW TO RESPONSE DUE TO WARM ADVECTION OVER COLD LAKE WATERS...BUT TOWARD MIDDAY EXPECTING SOUTH GALES TO BECOME PREVALENT. IT APPEARS AS THROUGH STRONGEST WINDS TO AROUND 40 KNOTS WILL OCCUR IN THE 21Z-06Z TIME FRAME...WITH WINDS SLOWLY DECREASING OVERNIGHT AND INTO TUESDAY MORNING. BY TUESDAY MORNING...A TROUGH OF LOW PRESSURE WILL BE APPROACHING LAKE MICHIGAN WITH A WEAKENING SFC PRESSURE GRADIENT THAT SHOULD ALLOW SOUTHWEST WINDS TO DROP INTO THE 15 TO 25 KNOT RANGE. THIS LULL IN WIND SPEEDS WILL BE SHORT LIVED AS ANOTHER LOW PRESSURE AREA DEVELOPS ACROSS THE CENTRAL PLAINS AND APPROACHES LAKE MICHIGAN TUESDAY AFTERNOON. AN ARCTIC AIR MASS WILL SPREAD OVER THE REGION IN THE WAKE OF THIS LOW PRESSURE ON TUESDAY EVENING...AND ANOTHER PERIOD OF GALES IS EXPECTED LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT FROM THE WEST NORTHWEST. SFC GRADIENT SHOULD SUPPORT CONTINUED GALES INTO WEDNESDAY MORNING ACROSS THE NORTH HALF OF THE LAKE. A RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING LOW PRESSURE AREA LATE WEDNESDAY...ALLOWING FOR WINDS AND WAVES TO SUBSIDE. LATE WEEK PERIOD SHOULD FEATURE EAST NORTHEAST WINDS AS LOW PRESSURE DEVELOPS ACROSS THE SOUTHERN PLAINS AND AS THE RIDGE OF HIGH PRESSURE DEPARTS TO THE EAST. IN TERMS OF HEADLINES...WILL EXTEND GALE WARNING FOR NEARSHORE AND OPEN WATERS TO COVER THE EXPECTED SOUTH GALES TODAY/TONIGHT...AND THEN WEST GALES LATE TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY. MARSILI && && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING FROM 9 AM THIS MORNING TO 6 AM CST WEDNESDAY FOR LMZ740>745-777-779. && $$ WFO LOT
AREA FORECAST DISCUSSION
NWS CHICAGO IL
1052 PM CST SUN JAN 27 2008 .DISCUSSION... 307 PM CST WITH HIGH PRESSURE EDGING EAST OVERNIGHT...SOUTH FLOW SHUD INCREASE OVERNIGHT. MODELS INDICATING SHARP INVERSION OVER SNOWPACK BUT WARMING WORKING DOWN TO SFC OVERNIGHT SO THAT AFTER INITIAL RADIATIVE DROP THIS EVENING...TEMPS SHUD PICK UP AND RISE OVERNIGHT TO ABV FRZG BY MRNG AND CONTINUE CLIMBING THRU MONDAY AS LOW LVL JET INCREASES TO 40KTS EARLY THEN TO NEAR 60KTS BY MIDDAY. VERY WK SHORT WAVE RIDING UP FROM THE DESERT SW TNGT FINDING SOME MID LVL CONVERGENCE OVER THE MS VLY ON MONDAY IN THE THERMAL RIDGE SPEARHEADED BY THIS JET. MAY HAVE A FEW SHOWERS DEVELOP AHEAD OF THIS WAVE IN THE LATE MRNG AND EARLY AFTN WITH LIGHT PCPN AMNTS ...CONSIDERING DRY LOW LVLS. ALSO LIKELY TO BE PRETTY WINDY IN THE AFTN AND EVENING HOURS MON AND CUD BE NEAR ADVISORY CRITERIA BUT PROBLY JUST UNDER. INITIAL SHOT PASSES IN AFTN AND LIKELY TO BE DRY GOING INTO EVENING WHEN ANOTHER PASSING MID LVL WAVE MAY AGAIN PROMPT SHOWER DEVELOPMENT. ASSUMING SOME WETTING OF LOWER LVLS FROM THE FIRST SHOT...RAIN CUD BE MORE CERTAIN IN THE EVENING WITH AN ODD CHANCE OF A RUMBLE OF THUNDER. WINDS SHUD START TO WEAKEN A BIT AFTER MIDNIGHT AS THE ASSOCIATED SFC LOW COMES SWINGING ACROSS THE MS VLY TOWARD TUES MRNG. THIS STRONG FRONT WILL SWING THRU ERN IL AND NW INDY IN THE AFTN CHANGING ANY RAIN TO SNOW. SNOW AMOUNTS CUD BE UP TO AND INCH OR TWO WHICH MAY GO UNDETECTED CONSIDERING WINDS WILL LIKELY PICK UP TO GALE FORCE OR BETTER. FUTURE CHOICES WILL BE FOR HIGH WIND WARNING OR WIND ADVISORY OR BLOWING SNOW ADVISORY OR POSSIBLY WINTER STORM WARNING FOR NEAR BLIZZARD CONDITIONS IF ENUF SNOW CAUSES VSBY TO DROP TO 1/4 MILE OR LESS. MODELS HAVE BEEN SLOWING FRONT MOVEMENT FROM PREVIOUS RUNS AND TIMING OF THIS MAY BE PUSHED BACK...SO NO HEADLINES AS YET...BUT OUTLOOKS WILL CARRY A CAVEAT FOR TUESDAY INTO TUESDAY NIGHT. THIS COLD BLAST WILL ALSO BE RESPONSIBLE FOR FALLING DAYTIME TEMPS ON TUESDAY...BACK INTO THE SINGLE DIGITS FOR MOST AREAS WED MORNING. WIND CHILLS WILL AGAIN BE A CONCERN IF NOT A HEADLINE. WINDS SLACK QUICKLY WED AS HIGH PRESSURE BUILDS IN FOR MIDWEEK. WARMING RETURNS TO THE 20S FOR HIGHS WED AND AGAIN THURSDAY AS UPR FLOW BACKS TO THE SW AGAIN. THIS HAPPENS AS ANOTHER LOW PRESS SYSTEM DEEPENS IN THE SRN PLAINS. THIS MAY PLAY A MAJOR ROLE AS A HEAVY SNOW MAKER THURSDAY INTO FRIDAY OVER THE MIDWEST. HIGH PRESSURE SHUD FOLLOW THIS SYSTEM FOR THE WEEKEND AND OFFER SOME QUIET TIME. RLB && .AVIATION... 0600 UTC TAFS THERE WILL BE AREAS OF FOG TONIGHT AS THE WARMER AIR MOVES ACROSS THE SNOW. AN INVERSION IS SEEN ON THE ACARS DATA AT 0325 UTC FROM SURFACE TO 2260 FT. THE WIND HAS DECEASED THIS EVENING AS A RESULT OF THE STABLE BOUNDARY LAYER SETTING UP. SATELLITE SHOWS NO LOW CLOUDS...JUST CIRRUS AT 25000 FEET. WILL HAVE A FORECAST OF SOUTH WIND 18 KNOTS WITH GUSTS TO 30 KNOTS MONDAY AFTERNOON. WE EXPECT SOME 5000 FT CLOUDS TO MOVE IN AHEAD OF THE RAIN MONDAY NIGHT. THEN AROUND 21 UTC WE EXPECT LIGHT RAIN TO MOVE INTO THE AREA FROM ROCKFORD TO CHICAGO. THE FORECAST SOUNDING SHOW A LARGE INCREASE IN WIND FROM THE SURFACE TO 1500 FEET BY MONDAY AFTERNOON. THE 925 MB LEVEL SHOWS 60 KNOT WIND OVER NORTHERN ILLINOIS BY 00 UTC TUESDAY. WILL ADD THE LOW LEVEL WIND SHEAR TO THE FORECAST UP TO 1500 FT FROM 2100 UTC THROUGH 06 UTC. && .MARINE... 234 PM CST WINDS ON LAKE MICHIGAN OVER THE NEXT THREE DAYS ARE EXPECTED TO REACH GALE FORCE DURING TWO DIFFERENT PERIODS AND FROM TWO DIFFERENT DIRECTIONS. WINDS THIS AFTERNOON HAVE BACKED TO THE SOUTHWEST AS A RIDGE OF HIGH PRESSURE MOVES EASTWARD ACROSS THE LOWER MS RIVER VALLEY. THE SOUTHERLY GRADIENT WILL INCREASE OVERNIGHT AS STRONG LOW PRESSURE DEVELOPS ACROSS THE DAKOTAS MONDAY. GALES EXPECTED BY MONDAY AS THE SFC PRESSURE GRADIENT CONTINUES TO STRENGTHEN. WINDS SHOULD DIMINISH BY LATE MORNING TUESDAY...BUT THE LULL IN STRONGER WINDS WILL BE SHORT LIVED AS ANOTHER SFC LOW DEVELOPS ACROSS THE MID MS RVR VALLEY AND TRACKS NORTHEAST INTO THE EASTERN GREAT LAKES ON TUESDAY NIGHT. ARCTIC AIR WILL OVERSPREAD THE REGION LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT BEHIND THIS SYSTEM...WHICH SHOULD ALLOW FOR A PERIOD OF WEST GALES FROM TUESDAY EVENING THROUGH WEDNESDAY. FREEZING SPRAY WILL LIKELY BECOME A CONCERN AGAIN LATE TUESDAY NIGHT...AND CONTINUING INTO WEDNESDAY. WINDS AND WAVES SHOULD SUBSIDE RATHER QUICKLY WEDNESDAY NIGHT AS A SURFACE HIGH SETTLES ACROSS THE WESTERN GREAT LAKES. GALE WARNING ISSUED THIS MORNING...AND WILL CONTINUE TO MONITOR FOR GALE WATCH TUESDAY NIGHT INTO WEDNESDAY. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING FROM 6 AM MONDAY TO 6 AM CST TUESDAY FOR LMZ740>745- 777-779. && $$ WFO LOT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
400 AM EST MON JAN 28 2008 LATEST UPDATE...ALL EXCEPT AVIATION... .SYNOPSIS...(400 AM EST MON JAN 28 2008) IT WILL BECOME WINDY THIS AFTERNOON AND TONIGHT OUT AHEAD OF AN INTENSE LOW PRESSURE SYSTEM WHICH WILL MOVE FROM THE NORTHERN PLAINS STATES TODAY TO THE LAKE SUPERIOR REGION TUESDAY MORNING. THIS SYSTEM WILL BRING RAIN FROM LATE TODAY THROUGH TONIGHT AND TUESDAY. A FEW THUNDERSTORMS ARE POSSIBLE OUT AHEAD OF THE COLD FRONT TUESDAY AFTERNOON AND VERY EARLY EVENING. IT WILL TURN SHARPLY COLDER AND VERY WINDY TUESDAY NIGHT BEHIND THE COLD FRONT. && .SHORT TERM...(400 AM EST MON JAN 28 2008) (TODAY THROUGH WEDNESDAY AFTERNOON) WINDY CONDITIONS WILL DEVELOP THIS AFTN AND PARTICULARLY TONIGHT AS A VIGOROUS LOW PRESSURE SYSTEM MOVES TO THE LAKE SUPERIOR REGION BY 12Z TUE. A FEW GUSTS MAY APPROACH WIND ADVISORY CRITERIA TONIGHT NEAR THE LAKE MI SHORELINE. HOWEVER 00Z GUIDANCE CONSENSUS AND 13KM RUC PROGGED SFC WIND GUSTS SUGGEST GUSTS AND CERTAINLY SUSTAINED WIND SPEEDS WILL REMAIN BELOW ADV CRITERIA. GREATEST IMPACTS FROM THIS SYSTEM WILL COME TUE AND TUE NIGHT. WE EXPECT A BAND OF GUSTY SHOWERS AND EMBEDDED CONVECTION TO RACE ACROSS OUR CWFA BETWEEN AROUND 20Z TUE AND 00Z WED. AN NCFR IS CERTAINLY POSSIBLE IN THAT TIME FRAME WITH POTENTIAL TO PRODUCE DAMAGING WIND GUSTS GIVEN KINEMATIC PROFILES AT THAT TIME. VERY WINDY CONDITIONS WILL DEVELOP BEHIND THE COLD FRONT TUE NIGHT. IMPACTS WILL LIKELY INCLUDE SCATTERED POWER OUTAGES. HIGH WIND GUSTS OF AT LEAST 45 TO 55 MPH ARE EXPECTED ACROSS OUR CWFA TUE NIGHT WITH HIGHEST GUSTS POTENTIALLY REACHING 65 MPH ALONG THE LAKE MI SHORELINE. WE ALREADY STRONGLY CONSIDERED A HIGH WIND WATCH FOR OUR CWFA FOR TUE NIGHT (ESPECIALLY FOR OUR LAKESHORE COUNTIES). ULTIMATELY AFTER COORD WITH SURROUNDING OFFICES WE FELT IT WAS A BIT EARLY FOR THIS HEADLINE. FUTURE SHIFTS WILL DEFINITELY NEED TO CONSIDER THIS AND MONITOR FUTURE GUIDANCE TRENDS CLOSELY. VERY STRONG CAA BEHIND THE COLD FRONT WILL RESULT IN A RAPID CHANGEOVER TO SNOW FROM WEST TO EAST TUESDAY EVENING. WE COULD SEE AN INCH OR TWO OF SNOW TUESDAY EVENING ESPECIALLY IF THE SECONDARY LOW PRESSURE WAVE DEVELOPS AS 00Z GFS GUIDANCE SUGGESTS. I BELIEVE THAT THIS SNOW IN CONJUNCTION WITH VERY STRONG WINDS AND PLUMMETING SFC TEMPS WILL LIKELY RESULT IN SLIPPERY TO ICY ROAD CONDITIONS AND VERY HAZARDOUS TRAVEL CONDITIONS TUESDAY NIGHT. WE DO NOT EXPECT MUCH LAKE EFFECT SNOW LATE TUESDAY NIGHT IN SPITE OF THE VERY STRONG CAA AND PLUMMETING 850 MB TEMPS. THE VERY STRONG WINDS WILL REALLY LIMIT AIRMASS RESIDENCE TIME OVER LAKE MI AND INVERSION HEIGHTS WILL CRASH WHICH WILL REALLY INHIBIT LES DEVELOPMENT. MAX TEMPS WED WILL BE ACHIEVED AT 05Z WED. WE WILL INDICATE STEADY TO SLOWLY FALLING TEMPS IN THE NDFD TEMP STRINGS FOR WED WITH APPARENT TEMP VALUES FALLING TO NEAR TO AROUND 10 BELOW ZERO BY WEDNESDAY MORNING. && .LONG TERM...(400 AM EST MON JAN 28 2008) (WEDNESDAY NIGHT THROUGH SUNDAY) THE MAIN CONCERN IN THE LONG TERM DEALS WITH THE STORM FOR THE END OF THE WEEK. RATHER LARGE DISAGREEMENT AMONGST THE MODELS CONCERNING THE TRACK OF THIS STORM. THE LATEST ECMWF HAS THE STORM TRACKING THROUGH SW LOWER MI AND THE TRACK OF THE 850 MB THERMAL RIDGE SUGGEST A MIX POSSIBLE FOR SOUTH CENTRAL LOWER MI. THE GFS TRACKS THE LOW THROUGH OH...WITH A SOLUTION THAT FAVORS SNOW. THE GLOBAL GEM SHOWS A TRACK CLOSER TO TO THE GFS. AT THIS POINT WILL MAINTAIN THE SNOW SCENARIO FOR THIS EVENT. PRECIPITATION IS LIKELY TO OCCUR AND WILL RAISE POPS ON FRI. WILL NEED TO MONITOR THE WED NIGHT FORECAST. THE LATEST NAM SHOWS A WEAK WAVE WITH SOUTHWEST WINDS PASSING THROUGH THE FORECAST AREA. TEMPS ARE COLD ENOUGH FOR LAKE ENHANCEMENT. THE GFS...GLOBAL GEM AND ECMWF DO NOT HAVE THIS...THUS WILL MAINTAIN A DRY FORECAST. && .AVIATION...(1134 PM EST SUN JAN 28 2008) THE LOW CLOUDS CONTINUE TO MOVE NORTH NORTHEAST OUT OF THE GRR CWA AS OF 11 PM. SEEMS THE LOW LEVEL "JET" ABOVE THE DISCONNECTED AIR BELOW RADIATION INVERSION HAS INCREASED WINDS NEAR 1500 AGL TO NEAR 20 KNOTS...BASED ON THE LATEST TAMDAR SOUNDINGS FROM THE LOCAL AREA. THAT HAS KEEP DENSE FOG FROM FORMING. DEW POINTS DOWN TO I-80 AT 11 PM WERE STILL IN THE MID TEENS. THAT AIR IS NOT MOIST ENOUGH TO RESULT IN ADVECTION FOG. BOTTOM LINE IS 3 TO 5 MILE VIS INTO MID MORNING WITH JUST CIRRUS CLOUDS OVER THE TAF SITES. THE WARM ADVECTION RAIN EVENT BEGINS MONDAY AFTERNOON AFTER 4 PM. CIGS WILL BECOME MVFR AS RAIN CONTINUES. MONDAY WILL BE WINDY AS THE 925 MB WIND IS 50 KNOTS BY 18Z. THUS THE TAF SITES WILL HAVE SOUTH WINDS AROUND 20 KNOTS WITH GUSTS NEAR 30 KNOTS BY MID DAY MONDAY. && .MARINE...(400 AM EST MON JAN 28 2008) GALE WARNING DELAYED (WILL NOT GO INTO EFFECT UNTIL 18Z THIS AFTN RATHER THAN 12Z) AND EXTENDED THROUGH 12Z WED AFTER COORD W/LOT AND IWX. GALE FORCE WINDS WILL DEVELOP THIS AFTN AND OVERNIGHT. WE BELIEVE A LULL IN WIND SPEEDS IS PROBABLE TUE MORNING/AFTN UNTIL FROPA. HOWEVER GALES WILL RETURN IN FORCE BEHIND THE FRONT AND THERE IS POTENTIAL FOR WINDS TO REACH STORM FORCE TUE NIGHT. FUTURE SHIFTS WILL NEED TO MONITOR THIS AND MODEL TRENDS REGARDING WIND SPEEDS/GUSTS CLOSELY. && .HYDROLOGY...(400 AM EST MON JAN 28 2008) SOME ICE JAMMING WILL CONTINUE TO DEVELOP ON VARIOUS RIVERS IN OUR HSA. HIGH STAGES AND/OR SIGNIFICANT FLUCTUATIONS IN RIVER LEVELS ARE POSSIBLE EARLY TO MIDWEEK DUE TO ICE JAM ISSUES. WARM TEMPS AND RAINFALL WILL MELT SOME SNOW COVER AND POTENTIALLY RESULT IN HIGHER RIVER LEVELS MID TO LATE WEEK. HOWEVER THIS SITUATION WILL BE MUCH DIFFERENT THAN WITH THE MUCH MORE SIGNIFICANT WARMUP WE HAD SEVERAL WEEKS AGO. WE DO NOT ANTICIPATE NEARLY AS RAPID A SNOW MELT SINCE THIS TIME TEMPS WILL ONLY REACH THE LOW TO PERHAPS MID 40S... WITH LOWER DEW POINTS TOO. FURTHERMORE BASIN AVG QPF WILL GENERALLY AVG AROUND AN INCH OR LESS FROM THIS AFTERNOON THROUGH TUESDAY NIGHT. WE WILL CONTINUE TO MONITOR ALL THIS VERY CLOSELY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING ST JOE TO MANISTEE 18Z THIS AFTN TO 12Z WED. && $$ SYNOPSIS: LAURENS SHORT TERM: LAURENS LONG TERM: MJS AVIATION: WDM MARINE: LAURENS HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1134 PM EST SUN JAN 27 2008 LATEST UPDATE...AVIATION... .SYNOPSIS...(400 PM EST SUN JAN 27 2008) A STRONG LOW PRESSURE SYSTEM CURRENTLY OVER THE WESTERN UNITED STATES WILL MOVE INTO THE PLAINS ON MONDAY. SOUTHERLY WINDS OVER MICHIGAN WILL INCREASE AS THIS SYSTEM MOVES EAST... SENDING WARMER AIR AND RAIN SHOWERS INTO THE REGION THROUGH TUESDAY. THIS WARM UP WILL BE BRIEF HOWEVER AS ARCTIC AIR AND SNOW SHOWERS WILL RETURN BEHIND A STRONG COLD FRONT TUESDAY NIGHT. && .SHORT TERM...(400 PM EST SUN JAN 27 2008) (TONIGHT THROUGH TUESDAY NIGHT) THE MAIN FOCUS IS THE ACTIVE WEST COAST TROUGH WHICH WILL BE ADVANCING EAST. FELT MORE COMFORTABLE WITH THE GFS SOLUTION WHICH IS SLOWER WITH THE TIMING OF THE COLD FRONT. WARMER AND WINDY IS THE MAIN MESSAGE MONDAY AND TUESDAY OUT AHEAD OF THE FRONT... ALONG WITH OCCASIONAL RAIN SHOWERS. EFFECTS OF SNOW COVER ON TEMPERATURES ARE CLEARLY SEEN TODAY OUT TO OUR WEST... WITH READINGS IN THE 50S OVER CENTRAL AND SRN IL BUT ONLY AROUND 30 WHERE SNOW PACK EXISTS IN THE NORTH. WILL STAY CONSERVATIVE WITH HIGH TEMPS ON MONDAY AND TUESDAY NOT EXCEEDING THE LOWER TO MID 40S. THIS MAY ACTUALLY BE TOO WARM IF THE STRONG LOW LEVEL INVERSIONS BELOW 2K FEET SHOWN IN NAM FCST SOUNDINGS ARE CORRECT. THIS INVERSION WILL ALSO HELP LIMIT THE GUSTINESS OF THE WIND. GUT FEEL IS THAT THE LOW LEVEL INVERSION WILL LIKELY HOLD STRONG ON MONDAY BUT HAVE A MUCH BETTER CHANCE OF MIXING OUT ON TUESDAY AHEAD OF THE FRONT. THUS WENT WARMER ON TUESDAY THAN MONDAY. BEST CHANCE OF MEASURABLE RAIN SHOWERS RELATED TO THE WARM ADVECTION LOOKS TO BE MONDAY AFTERNOON AND EVENING AS MID LEVEL THETA-E RIDGE COMES ACROSS. IT MAY JUST GO OVER TO MAINLY DRIZZLE/FOG LATE MONDAY NIGHT INTO TUESDAY MORNING AS THE MID LEVEL THETA-E RIDGE EXITS TO THE EAST AND HIGHER SFC DEW POINTS PUSH IN FROM THE SOUTH. PER THE GFS... ON TUESDAY AFTERNOON THE UPPER LOW CURRENTLY OVER SRN CA APPROACHES AND HELPS DEVELOP A STRONG WAVE ALONG THE APPROACHING COLD FRONT. IF THIS VERIFIES... A RATHER DEEP LOW MAY CRANK UP AND TRACK JUST TO OUR WEST AND NORTH. A DECENT THUNDER THREAT WOULD EXIST LATE TUESDAY WITH FROPA... THEN THE POTENTIAL FOR HIGH WINDS AND SNOW/BLOWING SNOW BEHIND THE FRONT AS THE ARCTIC AIR POURS IN. IN THE VERY NEAR TERM...CLEARING OF LOW CLOUDS EXPECTED TO ADVANCE FROM SW TO NE THIS EVENING AS LOW LEVEL WARM ADVECTION ARRIVES... BUT THIN HIGH CLOUDS WILL BE STREAMING IN FROM THE WEST. OVERALL AND PARTLY CLOUDY NIGHT AND COLD NIGHT IS IN STORE. WITH THE SNOW COVER AND CLEARING TEMPS COULD REALLY TUMBLE QUICK TONIGHT... BUT DID NOT GO MUCH BELOW MOS SINCE WINDS ARE PROGGED TO PICK UP AFTER MIDNIGHT. && .LONG TERM...(400 PM EST SUN JAN 27 2008) (WEDNESDAY THROUGH SUNDAY) CONCERNS DURING THE MEDIUM RANGE FOCUS ON A SOUTHERN STREAM STORM THAT MAY AFFECT THE AREA THURSDAY INTO FRIDAY. SCT SHSN EXPECTED WEDNESDAY IN THE WAKE OF THE EXITING DEEP LOW. DRY WX RETURNS WED NIGHT AND THURSDAY. THE GFS/ECMWF HAVE ADVERTISED A SOUTHERN STREAM SYSTEM TO MOVE FROM THE GULF THROUGH THE OHIO VALLEY TOWARD OHIO. THE LATEST OPERATIONAL GFS IS A BIT FARTHER NW OF THE ENSEMBLES AND TAKES THE LOW FROM MEMPHIS TO TOLEDO. THAT TRACK WOULD BE A DECENT SNOW PRODUCER FOR OUR CWA. THE ECMWF CONTINUES IT/S WWD MOVEMENT AND TAKES THE LOW OVER CENTRAL LOWER...WHICH COULD MEAN MORE RAIN THAN SNOW. CONFIDENCE IN THE OVERALL TRACK OF THIS SYSTEM ISN/T VERY HIGH. WE/LL LEAVE THE CURRENT CHC SNOW IN THE GRIDS AND NOT ADD ANY RAIN AND WAIT TO SEE HOW FUTURE MODEL RUNS PLAY THIS. && .AVIATION...(1134 PM EST SUN JAN 28 2008) THE LOW CLOUDS CONTINUE TO MOVE NORTH NORTHEAST OUT OF THE GRR CWA AS OF 11 PM. SEEMS THE LOW LEVEL "JET" ABOVE THE DISCONNECTED AIR BELOW RADIATION INVERSION HAS INCREASED WINDS NEAR 1500 AGL TO NEAR 20 KNOTS...BASED ON THE LATEST TAMDAR SOUNDINGS FROM THE LOCAL AREA. THAT HAS KEEP DENSE FOG FROM FORMING. DEW POINTS DOWN TO I-80 AT 11 PM WERE STILL IN THE MID TEENS. THAT AIR IS NOT MOIST ENOUGH TO RESULT IN ADVECTION FOG. BOTTOM LINE IS 3 TO 5 MILE VIS INTO MID MORNING WITH JUST CIRRUS CLOUDS OVER THE TAF SITES. THE WARM ADVECTION RAIN EVENT BEGINS MONDAY AFTERNOON AFTER 4 PM. CIGS WILL BECOME MVFR AS RAIN CONTINUES. MONDAY WILL BE WINDY AS THE 925 MB WIND IS 50 KNOTS BY 18Z. THUS THE TAF SITES WILL HAVE SOUTH WINDS AROUND 20 KNOTS WITH GUSTS NEAR 30 KNOTS BY MID DAY MONDAY. && .MARINE...(400 PM EST SUN JAN 27 2008) GALE WARNING IS UP FOR THE STRONG SOUTHERLY FLOW 12Z MON TO 12Z TUESDAY... BUT LACK OF DEEP MIXING LIKELY TO KEEP THINGS FROM GETTING TOO OUT OF HAND. LOOKING AHEAD TO TUESDAY NIGHT... IF GFS IDEA VERIFIES THEN GALE OR EVEN STORM WARNINGS SEEM LIKELY FOR THE NW FLOW BEHIND THE FRONT. && .HYDROLOGY...(400 PM EST SUN JAN 27 2008) SOME ICE JAMMING CONTINUES TO OCCUR ON VARIOUS RIVERS IN OUR HSA. HIGH STAGES AND/OR SIGNIFICANT FLUCTUATIONS WILL REMAIN POSSIBLE EARLY TO MIDWEEK. WARM TEMPS AND RAINFALL WILL MELT SOME SNOW COVER AND POTENTIALLY RESULT IN HIGHER RIVER LEVELS MID TO LATE WEEK. WE WILL HAVE TO MONITOR THIS CLOSELY. HOWEVER THE SNOW MELT WILL BE A FAIRLY SLOW AND GRADUAL PROCESS GIVEN AIR TEMPS ONLY REACHING THE LOW 40S LATE MON TO EARLY TUE AFTN (NOTHING LIKE THE MUCH MORE SIGNIFICANT WARM UP WE HAD SEVERAL WEEKS AGO). THEREFORE DO NOT ANTICIPATE A FAST SNOW MELT GIVEN THESE TEMPS AND LACK OF MORE SIGNIFICANT QPF MON-TUE (BASIN AVG QPF LESS THAN AN INCH ANTICIPATED WITH THIS SYSTEM). && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...GALE WARNING ST JOE TO MANISTEE 12Z MON TO 12Z TUE. && $$ SYNOPSIS: MEADE SHORT TERM: MEADE LONG TERM: 93 AVIATION: WDM MARINE: MEADE HYDROLOGY: LAURENS/MEADE
AREA FORECAST DISCUSSION
NWS CHICAGO IL
616 AM CST MON JAN 28 2008 .DISCUSSION... 402 AM CST UPPER TROUGH DEEPENING ACROSS WESTERN NORTH AMERICA TODAY...WITH SERIES OF MINOR SHORT WAVES RIPPLING NORTHEAST ALONG PERIPHERY OF STRONG JET INTO MIDWEST AND NORTHERN GREAT LAKES. SURFACE PRESSURES CONTINUE TO FALL ACROSS THE PLAINS IN RESPONSE TO JET AND UPPER TROUGH...STRENGTHENING SOUTHERLY LOW LEVEL FLOW INTO FORECAST AREA AND DRAWING WARM AIR RAPIDLY NORTH. PROFILER NETWORK INDICATES 50-60 KNOT SOUTHWEST 850 HPA JET SPREADING FROM TEXAS PANHANDLE NORTHEAST INTO UPPER MISSISSIPPI VALLEY PROVIDING IMPRESSIVE WARM ADVECTION AND HIGH CLOUDINESS TO THE REGION... THOUGH REGIONAL RADAR MOSAIC INDICATES LITTLE ORGANIZED PRECIPITATION. 00Z RAOB ANALYSIS INDICATES WHY...WITH 15-20 DEGREE DEW POINT DEPRESSIONS IN 925-850 HPA LAYER IN LOW LEVEL JET SOURCE REGION. SHORT TERM MODEL GUIDANCE DOES INDICATE SATURATION WILL EVENTUALLY OCCUR ACROSS THE AREA LATER TODAY...BUT HAVE REMOVED MENTION OF SHOWERS FOR THIS MORNING. SOUTHERN CALIFORNIA SHORT WAVE LIFTS ACROSS REGION THIS EVENING WITH 850 HPA WARM FRONT PUSHING NORTHEAST OF AREA OVERNIGHT...THUS EXPECT SHOWER COVERAGE TO BE HIGHEST DURING EVENING...THEN DECREASE SOMEWHAT OVERNIGHT AS STRONGER FORCING MOVES NORTHEAST OF FORECAST AREA. BIGGER CHALLENGE PERHAPS TODAY AND TONIGHT ARE TEMPERATURES...WITH BATTLE BETWEEN STRONG LOW LEVEL THERMAL ADVECTION AND REMAINING SNOW COVER ACROSS ESPECIALLY FAR NORTHERN IL. LOW LEVEL PARCEL TRAJECTORIES AND MODEL FORECAST 950 HPA TEMPS INDICATE 50S POSSIBLE ACROSS SOUTHERN PARTS OF CWA AND HAVE GENERALLY GONE ABOVE GUIDANCE TEMPS THERE...THOUGH HAVE STAYED CLOSER TO GUIDANCE IN MID 40S FARTHER NORTH WHERE RECEDING SNOW COVER WILL HAVE SOME EFFECT. WITH SURFACE PRESSURE GRADIENT MAINTAINING STRONG SOUTH WINDS OVERNIGHT...APPEARS ALL MOS GUIDANCE MUCH TOO COOL WITH OVERNIGHT MINS. MAIN UPPER TROUGH PUSHES TOWARD AREA ON TUESDAY...WITH STRONG HEIGHT FALLS DEVELOPING ACROSS THE AREA DURING THE DAY. COMBINATION OF STRONG LOW LEVEL FRONTOGENESIS AND FAVORABLE LEFT EXIT REGION OF UPPER JET STREAK SUPPORT MODEL DEPICTIONS OF DEEP VERTICAL MOTION DURING THE PERIOD...WITH STEEPENING MID LEVEL LAPSE RATES AND LOW LEVEL MOIST AXIS AHEAD OF COLD FRONT INCREASING POTENTIAL FOR CONVECTION. WRF AND GFS BOTH DEPICT WEAK ELEVATED CAPE FOR PARCELS JUST BELOW 850 HPA TUESDAY MORNING THUS WILL MAINTAIN MENTION OF ISOLATED THUNDER. APPEARS FROPA WILL OCCUR BY MIDDAY AT ROCKFORD...DURING EARLY/MID AFTERNOON IN CHICAGO AND DURING THE MID/LATE AFTERNOON FOR INDIANA COUNTIES. MODELS CONTINUE TO DEPICT THICKNESS VALUES FALLING RAPIDLY WITH FAIRLY QUICK CHANGE FROM RAIN TO SNOW EXPECTED...AND WEST/NORTHWEST WINDS GUSTING 30 TO 40 MPH. POTENTIAL FOR AN INCH OR SO OF SNOW TUESDAY AFTERNOON/EVENING...THOUGH WINDS WILL KEEP IT FROM ACCUMULATING UNIFORMLY AND WILL MENTION BLOWING SNOW AS WELL. PRECIP TO TAPER OFF FROM WEST TO EAST DURING THE EVENING WITH SUBSIDENCE AND STRONG LOW LEVEL DRY ADVECTION ALLOWING DECREASING CLOUDS/CLEARING AS ARCTIC AIR POURS IN. WITH TEMPS CRASHING INTO SINGLE DIGITS AND EVEN SOME SUBZERO READINGS...GUSTY WINDS WILL LIKELY SEND WIND CHILL READINGS INTO -20 TO -25 RANGE ACROSS NORTHERN IL BY EARLY WEDNESDAY MORNING. STORM EXITS QUICKLY TO THE EAST BY WEDNESDAY WITH WEAK SURFACE RIDGE MOVING ACROSS THE AREA AND ALLOWING WINDS TO DIMINISH THOUGH WITH COLD TEMPS CONTINUING BY AFTERNOON. MODELS REMAIN QUITE SIMILAR IN DIGGING ANOTHER UPPER TROUGH ACROSS THE WEST HOWEVER...RESULTING IN QUICK RETURN OF LOW LEVEL WARM ADVECTION ACROSS PLAINS TO OUR WEST WITH AREA OF LIGHT WAA SNOW INDICATED PERHAPS AS FAR EAST AS NORTHWEST IL/SOUTHERN WI WEDNESDAY NIGHT. LONGER RANGE GUIDANCE CONTINUES TO DEPICT STRONGER STORM SYSTEM THURSDAY/FRIDAY...THOUGH SIGNIFICANT DIFFERENCES CONTINUE WITH RESPECT TO TRACK OF SURFACE LOW. ECMWF CONTINUES TO BE FARTHEST WEST WITH LOW LIFTING FROM SOUTHERN PLAINS TO SOUTHERN LAKE MICHIGAN...00Z GFS CONTINUES TO FAVOR A TRACK FARTHER EAST UP THE OHIO RIVER...WHILE THE GEM IS IN BETWEEN WITH A TRACK MORE ACROSS OHIO. AT THIS DISTANCE WILL MAINTAIN CHANCE FOR SNOW ACROSS CWA THURSDAY NIGHT THROUGH FRIDAY AND CONTINUE TO HIGHLIGHT POTENTIAL FOR WINTER STORM SOMEWHERE NEARBY IN HAZARDOUS WEATHER OUTLOOK. RATZER && .AVIATION... 615 AM CST 1200 UTC TAFS...MAIN AVIATION CONCERNS TODAY WILL CENTER ON WINDS AND POTENTIAL OF RAIN SHOWERS THIS AFTERNOON AND EVENING. SURFACE PRESSURE GRADIENT WILL CONTINUE TO STRENGTHEN TODAY IN RESPONSE TO DEEPENING LOW PRESSURE ACROSS THE NORTHERN PLAINS. WIND SPEEDS HAVE BEEN SLOW TO INCREASE DURING THE NIGHT DUE TO A STRONG LOW LEVEL INVERSION EVIDENT ON ACARS SOUNDINGS. WINDS ALOFT HAVE BEEN STEADILY INCREASING WITH ACARS SOUNDING AT 09Z INDICATING LOW LEVEL WIND SHEAR CRITERIA BEING MET IN A LAYER FROM APPROX 1100-1400 FT. BEFORE LOW LEVEL INVERSION BEGINS TO WEAKEN A BIT THIS MORNING...WILL CONTINUE TO CARRY MENTION OF LOW LEVEL WIND SHEAR THROUGH MID MORNING. AS THIS INVERSION BEGINS TO WEAKEN SOMEWHAT...WIND SPEEDS SHOULD INCREASE INTO THE 20G30KT NEIGHBORHOOD BY LATE MORNING. IN TERMS OF SKY COVER...THICKER HIGH LEVEL CLOUDINESS WILL CONTINUE TO OVERSPREAD NORTHERN ILLINOIS THIS MORNING. MODEL GUIDANCE HAS BEEN SOMEWHAT CONSISTENT OVER PAST FEW DAYS IN INDICATING SHOWERS DEVELOPING ACROSS NORTHEAST ILLINOIS/NORTHWEST INDIANA IN ASSOCIATION WITH STRONG LOW LEVEL WARM/MOIST ADVECTION. GIVEN STRENGTH OF THIS ADVECTION WITH 55 KNOT LLJ DEVELOPING TODAY...WILL INCLUDE MENTION OF RAIN LATE THIS AFTERNOON. WINDY CONDITIONS WILL CONTINUE INTO TONIGHT WITH CHANCE OF RAIN PERSISTING IN ASSOCIATION WITH AN UPPER LEVEL SHORT WAVE TROUGH APPROACHING FROM THE PLAINS. THIS SHORT WAVE WILL LIFT NORTHEAST INTO THE UPPER GREAT LAKES OVERNIGHT WHICH SHOULD DECREASE RAIN CHANCES TOWARD MIDNIGHT. DID INTRODUCE MVFR CIGS/VSBYS AFT 00Z TONIGHT IN ASSOCIATION WITH PRECIP...WITH MVFR CIGS/VSBYS LIKELY LINGERING THROUGH THE OVERNIGHT HOURS. MARSILI && .MARINE... 315 AM CST A VERY ACTIVE MARINE PERIOD IN TERMS OF WINDS IS IN STORE FROM TODAY THROUGH WEDNESDAY. SOUTHERLY SURFACE PRESSURE GRADIENT WILL CONTINUE TO STRENGTHEN THIS MORNING. WINDS HAVE BEEN A BIT SLOW TO RESPONSE DUE TO WARM ADVECTION OVER COLD LAKE WATERS...BUT TOWARD MIDDAY EXPECTING SOUTH GALES TO BECOME PREVALENT. IT APPEARS AS THROUGH STRONGEST WINDS TO AROUND 40 KNOTS WILL OCCUR IN THE 21Z-06Z TIME FRAME...WITH WINDS SLOWLY DECREASING OVERNIGHT AND INTO TUESDAY MORNING. BY TUESDAY MORNING...A TROUGH OF LOW PRESSURE WILL BE APPROACHING LAKE MICHIGAN WITH A WEAKENING SFC PRESSURE GRADIENT THAT SHOULD ALLOW SOUTHWEST WINDS TO DROP INTO THE 15 TO 25 KNOT RANGE. THIS LULL IN WIND SPEEDS WILL BE SHORT LIVED AS ANOTHER LOW PRESSURE AREA DEVELOPS ACROSS THE CENTRAL PLAINS AND APPROACHES LAKE MICHIGAN TUESDAY AFTERNOON. AN ARCTIC AIR MASS WILL SPREAD OVER THE REGION IN THE WAKE OF THIS LOW PRESSURE ON TUESDAY EVENING...AND ANOTHER PERIOD OF GALES IS EXPECTED LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT FROM THE WEST NORTHWEST. SFC GRADIENT SHOULD SUPPORT CONTINUED GALES INTO WEDNESDAY MORNING ACROSS THE NORTH HALF OF THE LAKE. A RIDGE OF HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING LOW PRESSURE AREA LATE WEDNESDAY...ALLOWING FOR WINDS AND WAVES TO SUBSIDE. LATE WEEK PERIOD SHOULD FEATURE EAST NORTHEAST WINDS AS LOW PRESSURE DEVELOPS ACROSS THE SOUTHERN PLAINS AND AS THE RIDGE OF HIGH PRESSURE DEPARTS TO THE EAST. IN TERMS OF HEADLINES...WILL EXTEND GALE WARNING FOR NEARSHORE AND OPEN WATERS TO COVER THE EXPECTED SOUTH GALES TODAY/TONIGHT...AND THEN WEST GALES LATE TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY. MARSILI && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING FROM 9 AM THIS MORNING TO 6 AM CST WEDNESDAY FOR LMZ740>745-777-779. && $$ WFO LOT
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
835 AM EST MON JAN 28 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE AREA TODAY. THE HIGH WILL DRIFT OFF THE COAST EARLY TUESDAY ALLOWING FOR A COLD FRONT TO MOVE THROUGH THE REGION TUESDAY NIGHT. HIGH PRESSURE WILL BUILD IN BEHIND THIS FRONT FOR WEDNESDAY AND THURSDAY. THE NEXT STORM SYSTEM WILL ARRIVE THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL RETURN FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WATER VAPOR LOOP SHOWS UPPER LOW MOVING NORTHEAST OVER NEW ENGLAND WATERS. MEANWHILE...RIDGING IS BUILDING IN FROM THE MIDWEST...AHEAD OF A WEST COAST TROUGH. ACARS 400-250MB WIND OBSERVATIONS REVEAL NORTHWESTERLY FLOW ALOFT ON PERIPHERY OF UPPER RIDGE. A 125-150KT JET IS EXITING THE WEST COAST TROUGH ACROSS THE ROCKIES. 11Z SURFACE ANALYSIS PLACED AN OCCLUDED CYCLONE WELL OFF OF NEW ENGLAND...WITH A SECONDARY COLD FRONT SINKING SOUTH THROUGH NEW ENGLAND...BECOMING STATIONARY ACROSS NEW YORK STATE AND WESTERN QUEBEC. A 1024MB ANTICYCLONE WAS LOCATED ACROSS THE APPALACHIANS...WITH A TROUGH IN THE LEE OF THE MOUNTAINS. CORRIDOR OF STRATO-CU...WHICH DEVELOPED AS SUBSIDENCE INVERSION TRAPPED A THIN LAYER OF MOISTURE LAST NIGHT...IS MOVING TO THE NORTHEAST AT 5 MPH AS RIDGING BUILDS IN FROM THE WEST. COMBINATION OF CLOUD MOVEMENT...AND DIURNAL MIXING...SHOULD END UP YIELDING A MOSTLY SUNNY AFTERNOON ACROSS EASTERN ZONES. FURTHER WEST...EXPECT SUNSHINE WITH A FEW THIN CIRRUS INVADING FROM THE OHIO VALLEY THIS AFTERNOON. AS WARM ADVECTION CONTINUES TO OCCUR...SUNNY LOCATIONS WILL SEE TEMPERATURES CLIMB NEAR OR ABOVE 50F. TEMPERATURES MAY BE A FEW DEGREES TOO OPTIMISTIC EAST OF INTERSTATE 95 IF CLOUDS HOLD INTO THE EARLY AFTERNOON. WINDS BECOME LIGHT AS HIGH PRESSURE BUILDS INTO THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... HIGH OVER THE AREA FOR THE 1ST PART OF NGT...MOVG OFFSHORE OVRNGT. MDLS ARE GIVING LO CHC POPS TOWARDS TUE MRNG AS A WARM FNT MOVES INTO THE AREA. I AM A TOUCH SKEPTICAL ON THE PCPN CHCS - RDG STILL LOOKS ALONG THE CST BY 12Z...SO I`LL STAY W/ OUR CURRENT FCST OF SLT CHC ALONG THE BLUE RDG BY 12Z TUE. TEMPS MON NGT GNRLY U20S/L30S. && .LONG TERM /TUESDAY THROUGH SUNDAY/... RAISED TEMPS A FEW DEGREES TUES AFTN W/ INCR PRE-FRONTAL S/RLY WINDS. EVEN W/ INCR CLOUD COVER AND INCOMING PRECIP...SR MODELS PLACING A WEAK WARM FRONT...MORE OF A WEAK SFC TROF THO A BAROCLINIC ZONE REGARDLESS...JUST SOUTH OF MASON/DIXON LINE...ALLOWING FOR HIGHS NEAR 50 ACROSS THE PIEDMONT...U40S N OF THE BNDRY. NAM/GFS KEYING IN ON AN ELONGATED BAND OF PRECIP SPREADING NE ACROSS THE CWA TUES AFTN AND OVERNIGHT. NOT A VERY STRONG SIGNAL OF WAA...SO THE ISENTROPIC ASCENT WILL BE MINIMAL AND LOWER QPFS SHOULD RESULT FROM THE BEGINNING. RISING MOTION ALONG THE SFC TROF/BNDRY WILL BE THE MAIN FORCING...AS SW/RLY WINDS RIDE ALONG THE SLOW MOVING BNDRY. OVERNIGHT...THE SFC LOW BACK ACROSS THE GREAT LAKES REGION WILL STRENGTHEN...ALONG W/ A SHARPLY DEEPENING NEGATIVELY TILTED ACROSS THE EASTERN OHIO RIVER VALLEY. THE RESULTS WILL MOST LIKELY BE A STRONGER COLD FRONT W/ A MORE NORTH/SOUTH ORIENTATION...WHICH IS MORE FAVORABLE TO SPREAD PRECIP ACROSS THE MID ATLANTIC WHEREAS THE HIGHER ELEVATIONS WOULD NORMALLY SCATTER IT OUT BEFORE MAKING IT INTO THE PIEDMONT. LOW LEVEL WINDS WILL ALSO INCR JUST AHEAD OF A BEHIND THE FRONT...W/ 20-25KT GUSTS COMMON FOR THIS EVENT. THE STRONGEST WINDS LOOK TO BE OVERNIGHT AND EARLY WED W/ THE FRONTAL PASSAGE...MAINLY BEFORE 18Z WED. ANOTHER LEE TROF OVER THE CENTRAL/SRN PLAINS WILL GEAR UP THE NEXT SYSTEM AS A 1030MB HIGH SETTLES OVER THE MID ATLANTIC WED AND THURS. THE SFC HIGH WILL BRING MAINLY CLEAR SKIES...BUT KEEP TEMPS IN THE MID/U 40S W/ A WEAK N/RLY SFC FLOW AND COOLER TEMPS RIDING DOWN INTO THE REGION. THIS FLOW WILL ALSO BE THE FOCAL POINT FOR A POSSIBLE WEAK IN-SITU DAMMING SCENARIO. ANY CAD SITU THAT DEVELOPS WOULD LIKELY BE QUICKLY ERODED AS S/RLY FLOW INCR ON FRI AFTN. GFS SLIDES THE SFC LOW ACROSS LAKE ERIE...W/ THE ECMWF FURTHER WEST ACROSS MI. THE TRACK WILL HELP DETERMINE HOW STRONG THE PRE-FRONTAL S/RLY FLOW WILL BE IN AND IF ANY FROZEN PRECIP WILL RESULT. THICKNESS SUPPORT A RA/SN MIX FOR A BRIEF PERIOD EARLY FRI W/ THE ONSET...AND MAINLY ACROSS THE WESTERN HALF OF THE CWA. RA PREDOMINANT ACROSS THE COASTAL AND PIEDMONT REGIONS FRI MRNG/AFTN. HIGH PRESSURE OVER THE EASTERN HALF OF THE U.S. FOR THE END OF THE WEEK...INTO EARLY NEXT WEEK. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... EXPECT STRATO-CU TO DISSIPATE WITH DIURNAL MIXING AS CLOUDS GRADUALLY MOVE TO THE NORTHEAST LATE THIS MORNING. TWO SYSTEMS TO WATCH...MAINLY RAINMAKERS. TUES AFTN PRECIP WILL BEGIN TO REACH THE I-95 TAF SITES...MAINLY LIGHT/INTERMTNT TILL TUES NIGHT AHEAD OF THE COLD FRONT. S/RLY WINDS WILL INCR LATE TUES AND GUST TO 20-30KT RANGE W/ THE FRONTAL PASSAGE EARLY WED. WINDS WILL STAY IN THE 15-25KT RANGE THRU WED AS THE UPPER TROF PASSES. THURS FAIRLY QUIET...AHEAD OF ANOTHER LOW PRESSURE SYSTEM ON FRI AND EXITING THE REGION EARLY SAT. HIGH PRES FOR NEXT WEEKEND. && .MARINE... NORTHWEST WINDS BECOME LIGHT LATE THIS AFTERNOON AS THE SURFACE RIDGE MOVES OVER THE WATERS. SCA COND/S LATE TUES AND THRU MUCH OF WED. GUSTY WINDS WILL CHANNEL ACROSS THE BAY LATE TUES...AHEAD OF STRONG COLD FRONT...EXPTD TO MOVE ACROSS THE BAY EARLY WED. THE NEXT COLD FRONT EARLY SAT MRNG...W/ MORE SCA COND/S POSSIBLE FRI INTO EARLY SAT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...ABW NEAR TERM...ROGOWSKI SHORT TERM...ABW LONG TERM...GMS AVIATION...ROGOWSKI/GMS MARINE...ROGOWSKI/GMS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1125 AM EST MON JAN 28 2008 .UPDATE... FORECAST IS RATHER TRICKY FOR THIS AFTERNOON...PARTICULARLY WITH REGARDS TO PCPN POTENTIAL. 15Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED GENERAL UPPER LEVEL SW FLOW...BETWEEN A TROUGH OVER THE WESTERN U.S. AND A RIDGE FROM THE SOUTHERN PLAINS INTO THE EASTERN GREAT LAKES. PLENTY OF UPPER LEVEL MOISTURE STREAMING UP FROM THE EAST PACIFIC INTO THE GREAT LAKES REGION AS SEEN ON WATER VAPOR...WHICH VISIBLE SATELLITE IMAGERY AND SURFACE OBS INDICATES IS MOSTLY IN THE FORM OF HIGH CLOUDS. BELOW THESE HIGH CLOUDS...12Z RAOB AND TAMDAR SOUNDINGS ARE QUITE DRY...WITH 10-20C DEWPOINT DEPRESSIONS ACROSS THE REGION BETWEEN 900-500MB. THE SOUNDINGS DEPICT A STRONG INVERSION BETWEEN 900-850MB THANKS TO 850MB TEMPS OF 3C AT APX...7C AT GRB AND 12C AT MPX. NORMALLY THIS INVERSION WOULD MEAN TRAPPED LOW CLOUDS OVER THE AREA. HOWEVER...VISIBLE IMAGERY AND MOST SURFACE OBS (EXCLUDING SAW) SHOW VERY FEW IF ANY LOW CLOUDS ACROSS THE MIDWEST OR GREAT LAKES. THIS APPEARS MOSTLY DUE TO THE LACK OF LOW LEVEL MOISTURE...THOUGH DEWPOINTS ARE GENERALLY ON THE WAY UP NOW WITH MOST READINGS IN THE 25 TO 30 F RANGE. HIGHER DEWPOINTS...NEAR 40...ARE MOVING NORTHEAST THROUGH KS INTO SW IA ON A STRONG LOW LEVEL JET. 850MB WINDS ARE SW AT 60-65 KT AT PROFILERS ACROSS KS INTO NORTHERN MO. AT THE SURFACE...A 987MB LOW IS SITUATED NEAR BISMARCK...WITH ALL OF THE UPPER MISSISSIPPI VALLEY INTO THE GREAT LAKES IN THE WARM SECTOR. GIVEN THE PRESENCE OF SO MUCH DRY AIR IN THE LOW AND MID LEVELS...AM HIGHLY UNCERTAIN ON ANY PCPN OCCURRING TODAY. FOLLOWED THE DRIER NAM/RUC SCENARIO OVER THE GFS AS THEY SEEM TO BE DOING BETTER WITH RESPECT TO MOISTURE IN CURRENT TAMDAR SOUNDINGS. PLUS... CLIMATOLOGICALLY SPEAKING THE WARM SECTOR OF A SYSTEM IN WINTER IS NOT VERY FAVORABLE FOR PCPN BECAUSE MOISTURE IS HARDER TO COME BY. THEREFORE MADE A SOMEWHAT DRASTIC CHANGE AND WENT COMPLETELY DRY FOR TODAY. RAISED TEMPS SLIGHTLY GIVEN CURRENT READINGS ARE NEAR PREVIOUS FORECAST HIGHS...BUT HIGH CLOUDS WHICH SHOULD INCREASE THROUGH THE AFTERNOON WILL TEMPER READINGS FROM CLIMBING TOO HIGH. AS FAR AS TONIGHT GOES...WANTED TO LOWER POPS ACROSS THE BOARD...BUT THERE IS A BIT MORE DYNAMICAL FORCING TAKING PLACE. OVER THE WESTERN U.P....MODELS INDICATE SOME MID-LEVEL FRONTOGENESIS AND POSSIBLE JET COUPLING TAKING PLACE...WHICH COULD FORCE SATURATION AND PCPN. IN THE FAR EASTERN U.P....ISENTROPIC LIFT MOVING UP THROUGH MISSOURI INTO ILLINOIS (NOTED BY THICK MID-CLOUDS THERE) HEADS NORTHEAST AND COULD PRODUCE SOME LIGHT PCPN. THE CENTRAL U.P. GETS STUCK IN-BETWEEN PERHAPS INTO A DRIZZLE/FREEZING DRIZZLE. WILL SOMEWHAT HEDGE THE GOING FORECAST TOWARDS THIS SCENARIO...WITH MORE CHANGES FORTHCOMING ONCE THE 12Z GFS COMES IN TO SEE IF IT HANDLES THE MOISTURE BETTER. && .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE STORM POTENTIAL FOR TUESDAY THROUGH WEDNESDAY. WATER VAPOR IMAGERY AND RUC SHOWING A LONGWAVE TROUGH OVER THE PACIFIC NORTHWEST AND A FLATTEN RIDGE OVER GREAT LAKES REGION. A CLOSED LOW IS JUST OFF THE COAST OF THE MID ATLANTIC STATES. WEAK SHORTWAVES ARE OVER WESTERN ONTARIO...NORTH DAKOTA...AND WYOMING. SURFACE ANALYSIS DEPICTS A LOW OVER NORTH DAKOTA WITH A WARM FRONT LEADING IT STRETCHING INTO ILLINOIS. ANOTHER FRONTAL SYSTEM EXTENDS FROM WINNIPEG EAST TO JAMES BAY. AN ELONGATED RIDGE STRETCHES FROM GEORGIA NORTHEAST INTO SOUTHERN QUEBEC. THERE IS SOME FOG OVER THE EASTERN OHIO RIVER VALLEY AND THE LOWER GREAT LAKES. THE PACIFIC NORTHWEST LONGWAVE WILL SHIFT INTO THE NORTHERN HIGH PLAINS TODAY. THE RIDGE OVER THE GREAT LAKES WILL SHIFT INTO THE LOWER GREAT LAKES REGION AS THE LOW OFF THE ATLANTIC COAST WORKS NORTHEAST. THE SHORTWAVE CLIMBING THE RIDGE WILL GENERALLY STAY NORTH OF THE AREA TODAY...EXCEPT FOR THE SHORTWAVE OVER WYOMING WHICH WILL RACE UP THE RIDGE INTO THE FORECAST AREA THIS AFTERNOON. THE NOSE OF A 100+ KNOT UPPER LEVEL JET WILL SHIFT INTO WESTERN U.P. BY LATE AFTERNOON. THE SURFACE LOW OVER MONTANA WILL CATCH UP WITH THE LOW OVER NORTH DAKOTA AND MERGE AS THEY MOVE INTO WESTERN MINNESOTA. THE ACCOMPANYING WARM FRONT WILL SHIFT INTO WISCONSIN. THE LARGE RIDGE OVER THE EAST COAST APPEARS TO BE STEERING EVERYTHING NORTHEAST. THE RIDGE KEEPS A SOUTHERLY FLOW THROUGHOUT THE EASTERN CONUS DRAWING WARM AIR INTO THE GREAT LAKES REGION. THIS SHOULD PUSH TEMPERATURES INTO THE MID AND UPPER 30S OVER THE U.P. TODAY. THE INSTABILITY WITH THE SHORTWAVE...ISENTROPIC ASCENT AHEAD OF THE FRONTAL SYSTEM...AND LOW LEVEL MOISTURE WILL GENERATE PRECIPITATION. AN 850MB THERMAL TROUGH WILL SHIFT INTO THE AREA BY LATE AFTERNOON ALONG WITH CLOUD COVER. THE FORECAST SOUNDING PROFILE AND WARMER SURFACE TEMPERATURES SUGGEST THAT THERE WILL BE A MIX OF RAIN AND SNOW. A 50KNOT LOW LEVEL JET WILL SWEEP ACROSS THE FORECAST AREA TODAY. THE WARM SURFACE TEMPERATURES WILL HELP TO MIX SOME OF THESE WINDS TO THE SURFACE. MODELS IN PRETTY GOOD AGREEMENT WITH THE SYSTEM MOVING INTO THE GREAT LAKES WITH THE NAM ONLY A LITTLE FARTHER NORTH THAN THE CONSENSUS AND THE UKMET SLIGHTLY SLOWER. AS SUGGESTED BY HPC WILL GO WITH THE GFS/ECMWF BLEND. THE LONGWAVE TROUGH WILL MOVE INTO THE DAKOTA AND CENTRAL CANADA TONIGHT. SHORTWAVES EJECTED OUT AHEAD OF THE TROUGH WILL SWEEP THROUGH THE AREA TONIGHT. THE SURFACE LOW WILL MOVE OUT OF MINNESOTA AND INTO CENTRAL ONTARIO BY MIDNIGHT DRAGGING THE COLD FRONT INTO THE WESTERN U.P. AND LAKE SUPERIOR. WINDS AT THAT TIME WILL BEGIN TO VEER WEST AND NORTHWEST. ISENTROPIC ASCENT AHEAD OF THE FRONT AND WARM MOISTURE AIR WILL CONTINUE TO FEED RAINS OVER THE AREA. AS THE FRONT MOVES INTO THE AREA LATE TONIGHT...COLD AIR WILL ADVECT IN AND CHANGE THE RAIN TO SNOW OVER THE WESTERN U.P. THE TEMPERATURES WILL DROP RAPIDLY FOLLOWING THE FROPA. A SECONDARY LOW DEVELOPING ALONG THIS FRONT WILL WORK NORTHWARD ALONG THE FRONT AND REACH EASTERN IOWA BY SUNRISE. THE LONGWAVE TROUGH WILL REACH MINNESOTA AND EASTERN MANITOBA BY LATE TUESDAY AFTERNOON. WEAK SHORTWAVES AHEAD OF THE TROUGH WILL SWEEP THROUGH THE FORECAST AREA. THE SURFACE LOW WILL LIFT INTO NORTHEAST ONTARIO DRAGGING THE COLD FRONT INTO THE EASTERN U.P. THE SURFACE LOW MOVING UP THE FRONT AND WILL REACH NORTHERN LOWER MICHIGAN BY LATE TUESDAY. A -32C 850MB THERMAL WILL SHIFT INTO MINNESOTA. LOW LEVEL MOISTURE AND INSTABILITY ALONG WITH THE COLD AIR SPREADING ACROSS THE AREA WILL CHANGE THE PRECIPITATION TO SNOW BY LATE MORNING. THE TIGHT GRADIENTS BEHIND THE FRONT WILL INCREASE THE WINDS OVER THE WEST. THIS WILL PRODUCE SOME BLOWING SNOW BY LATE AFTERNOON. THE LONGWAVE TROUGH WILL MOVE OVER THE FORECAST AREA TUESDAY NIGHT. THE SURFACE LOW WILL TRACK TO EAST CENTRAL ONTARIO DRAGGING THE COLD FRONT THROUGH THE LOWER GREAT LAKES INTO THE MID ATLANTIC STATES. THE CENTRAL PLAINS RIDGE WILL ADVANCE INTO THE MIDDLE MISSISSIPPI RIVER VALLEY. THE 850MB THERMAL TROUGH WILL SHIFT INTO WESTERN LAKE SUPERIOR. WINDS WILL BE MAINLY FROM THE WEST TO NORTHWEST ACROSS LAKE SUPERIOR. A 40KNOT LOW LEVEL JET WILL SETTLE OVER THE FORECAST AREA OVERNIGHT. THE COLD 850MB TEMPERATURES WILL PROMOTE MIXING SOME OF THESE WINDS TO THE SURFACE. THE COLD TEMPERATURES AND WINDS WILL GENERATE LAKE EFFECT SNOWS AND BLOWING SNOW MAINLY OVER THE WEST END. A WINTER STORMS WATCH MAY BE WARRANTED. WIND CHILLS COULD REACH ADVISORY CATEGORY LATE. SINCE IT COULD BE AN ADVISORY WILL HOLD OFF ON ISSUING IT AT THIS TIME. THE LONGWAVE TROUGH WILL SWING INTO NORTHERN ONTARIO AND SOUTHERN QUEBEC ON WEDNESDAY. THE SURFACE LOW WILL LIKEWISE SWING INTO QUEBEC WHILE THE RIDGE PUSHES DEEPER INTO THE UPPER MISSISSIPPI RIVER VALLEY. ANTI-CYCLONIC FLOW WILL DRAW COLDER AIR INTO THE UPPER GREAT LAKES REGION. DRY AIR WILL OVERSPREAD THE REGION AS WELL. THE THERMAL TROUGH WILL SUPPORT LOW LEVEL INSTABILITY AND LAKE EFFECT SNOWS. THE WINDS WILL MIX DOWN OVER LAKE SUPERIOR SO EXPECT TO SEE MORE BLOWING SNOW. WITH THE TEMPERATURES AS COLD AS IT WILL BE...EXPECT TO SEE FINER FLAKES WHICH WITH THE WINDS WILL REDUCE VISIBILITY GREATLY. THE LONGER FETCH ACROSS THE CENTRAL AND EASTERN PART OF LAKE SUPERIOR WILL CONTRIBUTE GREATLY TO SIGNIFICANT LES OVER THE LUCE...ALGER AND EVEN NORTHERN SCHOOLCRAFT COUNTIES. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... UPDATE FOR SAW...AMENDED THE TAF AS LOW CLOUDS HAVE COMPLETELY DISSIPATED. 12Z SOUNDINGS AND AREA TAMDARS SHOW PLENTY OF DRY AIR EVEN IN THE LOW LEVELS...WHICH COMBINED WITH THE STRONG SOUTHERLY WIND HAS ALLOWED LOW CLOUDS TO SCATTER OUT. HAVE STILL FOLLOWED THE IDEA OF LOW CLOUDS COMING IN...BUT NOT UNTIL 01Z. EVEN THIS MIGHT BE A LITTLE TOO PESSIMISTIC. MORE DETAILS COMING WITH THE 18Z TAF ISSUANCE. PREVIOUS AVIATION DISCUSSION... TRICKY FCST FOR SAW WITH SHALLOW INVRN AND SOME LO CLD/FOG UPSTREAM TO THE S. TENDED ON THE PESSIMISTIC SIDE WITH LO CLD AS UPSLOPE SLY FLOW THERE WL TEND TO MAINTAIN HI RH IN SHALLOW COLD WEDGE THAT MIGHT HAVE DIFFICULTY MIXING OUT COMPLETELY. A LIGHT WINTRY MIX OF PCPN IS LIKELY LATE TDAY/THIS EVNG AS SOMEWHAT HIER MSTR IS STREAMING NEWD FM THE SRN PLAINS...BUT PCPN SHOULD BE ON THE LGT SIDE WITH PERSISTENT DRY MID LVLS TRYING TO HANG ON. COOLING OF LLVLS TNGT WL MAINTAIN MORE LO CLD/FOG AND PSBLY SOME FZDZ AT SAW. THE FCST FOR CMX IS A BIT MORE STRAIGHT FORWARD AS UPSRTREAM AIRMASS TO THE SSW IS WARMED/DRIED BY DOWNSLOPING OFF THE HIER TERRAIN. SO... EXPECT VFR CONDITIONS TO PREDOMINATE THERE THRU THE DAY. APRCH OF LO PRES TO THE NW OF LK SUP TNGT MAY RESULT IN A PD OF RASN...WITH DETERIORATING CONDITIONS AS LLVLS BEGIN TO MOISTEN. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LO PRES DVLPG IN THE NORTHERN PLAINS THIS MRNG TO MOVE INTO MN THIS EVENING AND THEN ONTARIO ON TUE MRNG WHILE DEEPENING. SLY GALES HAVE DVLPD AS FCST OVER ECNTRL LK SUP...AND THESE WL CONTINUE INTO TNGT BEFORE PRES GRADIENT GRDLY EASES LATE TNGT. A STRONG ARCTIC COLD FRONT WILL CROSS LAKE SUPERIOR ON TUE AS THE LO MOVES TO NEAR JAMES BAY IN THE EVNG. ANOTHER LO PRES SYS WILL DEVELOP ON THE COLD FRONT OVER THE LOWER GREAT LAKES LATE ON TUE AND MOVE INTO SE CAN AND INTENSIFY ON WEDNESDAY. GALE TO STORM FORCE W TO NW WINDS AND HEAVY FRZG SPRAY WL DVLP IN THE WAKE OF THE COLD FNT AND THE DVLPG LO ON THIS BNDRY AS ARCTIC AIR SURGES OVER LK SUP. PLAN ON THE STRONGEST WINDS FM THE KEWEENAW AND ISLE ROYALE TO THE E. AS THE LO CONTINUES NE ON THU...A HI PRES RDG WL BUILD TOWARD THE UPPER GREAT LAKES. ON FRI...A DEVELOPING LO OVER THE TENNESSEE VALLEY IS EXPECTED TO SHIFT NE TO THE EASTERN GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... MICHIGAN...WINTER STORM WATCH FROM 1 PM TUESDAY TO 7 PM WEDNESDAY FOR MIZ001>003. MICHIGAN...WINTER STORM WATCH FROM 7 PM TUESDAY TO 7 PM WEDNESDAY FOR MIZ006>007-085. LAKE SUPERIOR...GALE WARNING UNTIL 4 AM EST TUESDAY FOR LSZ266-267. LAKE MICHIGAN...GALE WARNING FROM 11 AM THIS MORNING TO 1 AM EST TUESDAY FOR LMZ248-250. && $$ UPDATE...AJ DISCUSSION...DLG AVIATION...KC/AJ MARINE...KC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
955 AM EST MON JAN 28 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY BRINGING DRY CONDITIONS AND MILD AIR. LOW PRESSURE OVER THE MIDWEST WILL PUSH SLOWLY EAST AND PUSH LIGHT PRECIPITATION INTO THE AREA TUESDAY AND EARLY WEDNESDAY. A COLD FRONT ON WEDNESDAY WILL BRING COLDER AIR BACK INTO REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 950 AM...SFC HI PRES RDG CNTRD OVER WRN NY WITH XTNSV LOW CLD DECK OVER MUCH OF THE BGM CWA. SOME CLEARING ACRS FAR ERN ZONES BUT CLDS HOLDING TUFF ALONG AND W OF I-81. ACARS DATA FROM ASCENDING BGM FLIGHT THIS MRNG SHOWED NEARLY SATURATED CONDITIONS TO JUST BLO 850 MB (SIMILAR TO 12Z BUF SNDG). WITH RDG AXIS OVERHEAD AND LGT WINDS, THINK CLDS WILL HOLD FIRM OVER THE FINGER LAKES AND CNTRL SRN TIER WELL INTO THE AFTN. CLDS MAY EVEN WORK BACK INTO THE WRN MOHAWK VLY AND CATSKILLS THIS AFTN. HOWEVER, THINK OVERALL TREND WIL BE FOR IMPVNG CONDITIONS AND WILL INDICATE PC SKIES BY MID/LATE AFTN MOST AREAS, AS SUGGESTED BY LATEST RUC PROFILES. PREV BLO... LOPRES SPINS OVER THE WRN ATLANTIC WHILE A SHARP RDG BUILDS OVER THE FCST AREA. AS USUAL...LGT NLY FLOW HAS RESULTED IN AN XTNSV SC CVR OVRNGT EVEN WHILE CI DUMPS OVER THE TOP OF THE RDG. BACK EDGE OF THE SC MAKING STEADY PROGRESS OVER WRN PA. LWR DEW PTS IN THE CNTRL AND ERN ZONES MAY HELP ERODE THE CLDS SO WILL SIMPLY FCST PTLY SUNNY SKIES FOR TODAY AS THE BACK EDGE WORKS EAST AND THE ERN CLDS ERODE IN THE DRY AIR. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... LOPRES IS OVER NW MN 00Z TUE AS THE MODELS CONT THEIR TREND OF TRACKING THE SYSTEM FURTHER WEST. UA LOW CLOSES OFF LTR TUE AS THE SYSTEM GOES NEG. REALL NO FRCG MECHANISM FOR PCPN OVER THE FCST AREA UNTIL THE COLD FNT PUSHES THRU 06Z TO 12Z WED. OPERATIONAL GFS HAS BACKED OFF ON THE EARLY QPF AND IS MORE IN LINE WITH THE NAM FOR ANY PREFNTL PCPN. STILL...BOTH THE GFS AND NAM DOP SOME LGT PCPN OVER THE AREA BEGINNING EARLY TUE...AND IF IT FALLS...TEMPS WILL BE COLD ENUF FOR SOME LGT FRZG PCPN. SO WHILE I BELIEVE THE CHANCE IS SMALL...HAVE ELECTED TO KEEP CHANCE POPS IN THE WEST FOR NOW. SOME LGT PCPN IS PSBL DURING TUE DAYLIGHT HRS BUT ONCE AGAIN THERE IS LTL TO FORCE THE PCPN. WILL STICK WITH CONTNUITY AND KEEP THE LGT PCPN DURING TUE. NEG TILT UA TROF ACCOMPANIES THE COLD FNT EARLY WED AND FINALLY SOME LIFT FOR PCPN. DEEPER...FURTHER WEST LOW HAS DELAYED THE PASSAGE OF THE COLD FNT AND ARRIVAL OF THE COLD AIR SO IN TURN HAS DELAYED THE CHG OVER TO SNOW UNTIL LTR. VERY DRY AIR BHD THE FNT WILL LIMT THE LES ACTIVITY BUT IT DOES LOOK AS THOUGH THE FLOW WILL BE FVRBL FOR SOME LES OVER THE NRN ZONES...ESP LTR WED AS THE COLD AIR BECOMES ESTABLISHED. GOOD GRADIENT AND PRESSURE RISES ON WED WILL RESULT IN VERY WINDY CONDS BHD THE FNT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... FOCUS THIS PERIOD CONTINUES TO BE ON CYCLONE MOVING OUT OF THE PLAINS THROUGH THE OHIO VALLEY THURSDAY NIGHT. THIS SYSTEM WILL SPREAD PRECIPITATION INTO OUR REGION AFTER MIDNIGHT, WITH PRECIPITATION INTENSITY INCREASING ON FRIDAY. CURRENT MODEL SOUNDINGS INDICATE THE PRECIPITATION WILL BE MAINLY SNOW THURSDAY NIGHT, WITH SOME SLEET MIXING IN TOWARD MORNING... PARTICULARLY OVER SOUTHERN HALF OF REGION. FRIDAY WILL SEE WARM AIR CONTINUE TO SURGE NORTHWARD AHEAD OF COLD FRONT, CHANGING PTYPE FOR SOUTHERN HALF OF FORECAST AREA TO RAIN. A MIX WILL HOLD ON OVER THE NORTHEAST WHERE COLD AIR REMAINS ENTRENCHED. ONCE THE COLD FRONT PULLS THROUGH DURING THE AFTERNOON, EXPECT THE MAIN PTYPE TO GO BACK OVER TO SNOW. BIGGEST CONCERN WITH THIS EVENT WILL BE MIXED PRECIP, AS THERE APPEARS TO BE ENOUGH WARM AIR IN THE MODELS TO PRECLUDE STRONG SNOW GROWTH. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... LOW CLOUDS WILL BURN OFF AND RISE TO A SCATTERED 3000-5000 LAYER BETWEEN 13Z AND 15Z. SKIES WILL FURTHER CLEAR THIS AFTERNOON AS DRIER AIR MOVES OVER THE REGION. EXPECT FAIRLY LIGHT WINDS TODAY, GENERALLY 5 TO 10 KTS BY LATE MORNING. SKIES WILL REMAIN MAINLY CLEAR UNTIL EARLY TUESDAY MORNING, WHEN A LOW VFR DECK WILL THICKEN IN ADVANCE OF A WARM FRONT. OUTLOOK...MVFR RESTRICTIONS LIKELY FROM TUES INTO TUES NGT WITH CDFNT. GUSTY WINDS WILL PRECEDE AND FOLLOW THIS FNT. RAPID CLEARING WITH VFR BY WED AFTN...PERSISTING THRU THURSDAY. SRN STREAM SYSTEM APRCHS THU NGT WITH MVFR/IFR CONDITIONS INTO FRIDAY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DGM NEAR TERM... SHORT TERM...DGM LONG TERM...DJP AVIATION...DJP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
455 AM CST MON JAN 28 2008 .SHORT TERM....TODAY THROUGH TUESDAY...PCPN TRENDS...EFFECTS OF ARCTIC COLD FRONTAL PASSAGE AND WINTER WX HEADLINES ARE THE FOCUS DURING THIS PERIOD. HAVE PULLED POPS FROM THE MORNING FCST...AS MODELS CONTINUE TO DELAY THE ONSET OF PCPN OVER C/NE WI...AND UPSTREAM OBS SHOW MAINLY HIGH CLOUDS UPSTREAM. WILL KEEP LIKELY POPS FOR THIS AFTERNOON...WITH FAIRLY LGT QPF. GIVEN THE LATER ARRIVAL TIME AND EXPECTED HIGH TEMPS IN THE UPPER 30S TO LOWER 40S...WILL JUST MENTION LIGHT RAIN ATTM. TONIGHT...DEEPER SATURATION OCCURS DURING THE EVG HOURS... COINCIDENT WITH THE ARRIVAL OF A S/W TROF AND SOME JET ENERGY. DYNAMIC/EVAPORATIVE COOLING NEARLY WIPE OUT THE WARM LYR ALOFT OVER NORTHERN WI DURING THE EARLY EVG...OPENING UP THE POSSIBILITY OF A MIX OF RAIN/SNOW/SLEET. A DRY SLOT ARRIVE AFTER MIDNIGHT... LIKELY RESULTING IN A DECREASE IN PCPN OVERNIGHT. HAVE REDUCED POPS TO CHC CATEGORY...AND MENTIONED MAINLY LGT RAIN...DRIZZLE AND AREAS OF FOG. THE LEADING EDGE OF THE ARTIC BOUNDARY MAY SLIP INTO OUR NW COUNTIES OVERNIGHT...LEADING TO THE POSSIBILITY OF SOME FZDZ IN NC/C WI. ON TUES...THE POWERFUL ARCTIC FRONT IS EXPECTED TO SHIFT THROUGH THE FA DURING THE 12-18Z PERIOD...WITH THE COLDEST AIR SURGING INTO THE RGN DURING THE AFTERNOON. A MIX OF LIGHT RAIN OR FREEZING RAIN WILL OCCUR DURING THE MORNING...FOLLOWED BY SNOW DURING THE AFTERNOON AS DEEP FRONTOGENETIC FORCING AND UPPER DIVG AHEAD OF A STG NEGATIVELY-TILTED S/W TROF ARRIVE. EXPECT ACCUMS OF 1-3 INCHES OF POWDERY SNOW BY EVG. COMBO OF STG CAA AND INCREASING ISALLOBARIC GRADIENT WILL CAUSE A SIGNIFICANT INCREASE IN WEST WINDS DURING THE AFTERNOON...WITH GUSTS TO 35-45 MPH CAUSING CONSIDERABLE BLOWING/DRIFTING SNOW. TEMPS WILL FALL SHARPLY DURING THE AFTERNOON. GIVEN THE COMBINED THREAT OF FREEZING PCPN...SOME MODEST SNOW ACCUMS...STG WINDS AND ASSOC BLOWING SNOW AND FALLING TEMPS...HAVE OPTED TO ISSUE A WINTER WEATHER ADVSY FOR THE ENTIRE CWA THROUGH TUES NGT. .LONG TERM...TUESDAY NIGHT THROUGH NEXT SUNDAY WINDY CONDITIONS ALONG WITH SNOW AND BLOWING SNOW WILL CREATE HAZARDOUS CONDITIONS FOR AIRCRAFT OR BY CAR. PER COORDINATION WITH SURROUNDING OFFICES AND WITH THE SHORT TERM FORECASTER... MANY DIFFERENT HEADLINE OPTIONS WERE DISCUSSED DUE TO THE DIFFERENT TYPES OF PRECIPITATION ON TUESDAY MORNING...THEN SNOW AND CONSIDERABLE BLOWING AND DRIFTING SNOW AS THE ARCTIC COLD FRONT RACES ACROSS THE AREA TUESDAY AFTERNOON AND TUESDAY EVENING. DECIDED TO GO WITH A WINTER WEATHER ADVISORY FOR MUCH OF TUESDAY UNTIL 12Z WEDNESDAY. FOR MY PART OF THE FORECAST...WILL BE DEALING WITH BAND OF SNOW EXITING THE REGION ALONG WITH CONSIDERABLE BLOWING AND DRIFTING OF THE SNOW. WIND GUSTS OVER 40 MPH WILL CREATE NEAR BLIZZARD CONDITIONS AT TIMES. ALONG WITH THE WHITE OUT CONDITIONS...EXPECTING AREA ROADS TO FREEZE UP DUE TO THE RAINFALL EARLY IN THE DAY AND THEN SNOW AND BLOWING SNOW DURING THE AFTERNOON ALONG WITH TEMPERATURES FALLING WELL BELOW FREEZING. THE EVENING COMMUTE ACROSS NORTHEAST WISCONSIN COULD BE VERY TREACHEROUS DESPITE SANDING AND SALTING OF AREA ROADS. THE SNOW SHOULD DIMINISH QUICKLY TO SCATTERED FLURRIES TUESDAY EVENING. AREAS OF BLOWING SNOW SHOULD CONTINUE OVERNIGHT. LATER TUESDAY NIGHT...WIND CHILL READINGS WILL APPROACH WARNING CRITERIA...35 BELOW ZERO OR LOWER ACROSS CENTRAL AND NORTH CENTRAL WISCONSIN. WIND CHILL ADVISORY CRITERIA SHOULD BE MET OVER THE REMAINDER OF NORTHEAST WISCONSIN WITH WINDS OF 25 TO 35 BELOW ZERO. ALSO HAVE LOWER MINIMUM TEMPERATURES SEVERAL DEGREES ON WEDNESDAY...HAVE UNDERCUT GUIDANCE BY 5 DEGREES AND CUT AROUND 10 DEGREES OFF CURRENT HIGHS. DESPITE PARTLY CLOUDY CONDITIONS... TEMPERATURES WILL STRUGGLE INTO THE SINGLE DIGITS ABOVE ZERO. DO NOT PUT AWAY THE SNOW SHOVELS. AN ACTIVE PATTERN IS SETTING UP LATER THIS WEEK...AND MODELS SUGGESTING A SIGNIFICANT SNOWFALL BEYOND THE FORECAST PERIOD EARLY NEXT WEEK. RETURN FLOW SETS UP WEDNESDAY NIGHT AND MODELS ARE STRUGGLING WITH LOW LEVEL MOISTURE. HAVE INCREASED SNOW CHANCES OVER THE SOUTH WEDNESDAY NIGHT INTO THURSDAY NIGHT. DEPENDING ON THE LOW LEVEL MOISTURE...COULD BE SEVERAL INCHES OF SNOW DURING THIS PERIOD. A SECONDARY STORM IS EXPECTED TO DEVELOP AND MOVE TOWARDS THE GREAT LAKES REGION. THE 00Z ECMWF TONIGHT WOULD SUGGEST THAT A WINTER STORM WATCH WILL NEEDED ACROSS NORTHEAST WISCONSIN AS THIS MODEL TRACKS THE SYSTEM FURTHER WEST THAN THE CANADIAN/GFS. MY HUNCH IS THAT THE GFS/CANADIAN WILL TREND FURTHER WEST ON LATER MODEL RUNS. PLENTY OF TIME TO SORT THE DETAILS ON THIS FEATURE AND WILL BE WATCHING IT CLOSELY OVER THE NEXT SEVERAL DAYS. THE OTHER SIGNIFICANT STORM WILL OCCUR NEXT MONDAY INTO TUESDAY. BOTH THE ECMWF AND GFS ARE CRANKING OUT 1.00 TO 2.00 INCHES OF LIQUID QPF. IF THIS FALLS AS SNOW...THIS WOULD EQUATE TO 10 TO 20 INCHES OF SNOW. THE GFS IS FURTHER WEST AND WOULD SUGGEST SOME RAIN OVER THE SOUTHEAST PORTION OF THE FORECAST AREA. ANOTHER SYSTEM TO WATCH OVER THE NEXT WEEK. THE ECMWF WOULD SUGGEST ALL SNOW. && .AVIATION...ASIDE FROM SOME MVFR VSBYS IN LIGHT FOG THIS MORNING... EXPECT VFR CONDITIONS TO PREVAIL UNTIL MID-LATE AFTERNOON...WHEN LIGHT RAIN AND ASSOC MVFR CONDITIONS ARE EXPECTED TO DEVELOP. EXPECT CIGS/VSBYS TO LOWER TONIGHT DUE TO RAINFALL AND INCREASING DEW POINTS OVER A DEEP SNOWPACK. SOME FZDZ/LIGHT FZRA IS PSBL OVER PARTS OF C/NC WI LATE TONIGHT. LLWS WILL CONTINUE TODAY INTO TONIGHT...THEN DIMINISH OVERNIGHT AS WINDS ALOFT DECREASE. && .MARINE...A GALE WARNING WILL BE IN EFFECT THROUGH TUESDAY NIGHT. SOUTH GALES WILL DEVELOP THIS MORNING AND CONTINUE INTO TONIGHT. WINDS WILL SUBSIDE A BIT DURING THE DAY ON TUESDAY...THEN INCREASE TO GALE FORCE FROM THE WEST LATER TUESDAY INTO TUES NGT AS AN ARCTIC FRONT MOVES THROUGH. WILL NEED TO MONITOR THE POTENTIAL FOR A BRIEF PERIOD OF STORM FORCE GUSTS TUESDAY EVG AS STG CAA AND THE CORE OF STRONGEST PRESSURE RISES MOVES THROUGH. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 12 PM TUESDAY TO 6 AM CST WEDNESDAY FOR WIZ022-038>040-048>050-073-074. WINTER WEATHER ADVISORY FROM 9 AM TUESDAY TO 6 AM CST WEDNESDAY FOR WIZ005-010>013-018>021-030-031-035>037-045. && $$ KIECKBUSCH/ECKBERG