AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 435 AM MST MON NOV 17 2008 .SHORT TERM... (TODAY AND TONIGHT) CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS CONTINUES TO INDICATE WEAK NORTHWEST FLOW ALOFT ACROSS THE STATE WITH HIGH AMPLITUDE RIDGING IN PLACE ACROSS THE DESERT SW THROUGH THE GREAT BASIN AND A BROAD UPPER TROUGH PERSISTING ACROSS THE CENTRAL CONUS THROUGH THE EASTERN SEABOARD ATTM. WATER VAPOR INDICATING MINOR EMBEDDED SHORT WAVE MOVING ACROSS THE NORTHERN HIGH PLAINS WITH ASSOCIATED BACK DOOR FRONT MOVING THROUGH THE FAR SE PLAINS AND SW KANSAS WITH 2-3MB 3 HOUR PRESSURE RISES BEING REALIZED ACROSS NORTHWEST KANSAS ATTM. CURRENT SATELLITE INDICATING SOME HIGH LEVEL CLOUDS ASSOCIATED WITH MINOR WAVE MOVING ACROSS THE SE PLAINS WITH MAIN BAROCLINIC CLOUD SHIELD WELL EAST OF THE AREA ACROSS WEST CENTRAL NEBRASKA AND CENTRAL KANSAS ATTM. THE PASSING BOUNDARY ALONG WITH WEAK LEE TROUGHING ALONG THE I-25 CORRIDOR AND WARM AIR ALOFT KEEPING TEMPERATURES RATHER MILD ATTM...WITH CURRENT READINGS IN THE 30S AND 40S ACROSS THE LOWER EASTERN SLOPES AND EASTERN PLAINS AND IN THE 20S AND 30S ACROSS MUCH OF THE HIGHER TERRAIN AND HIGH VALLEYS. TODAY AND TONIGHT...MAIN CONCERN REMAINS TEMPERATURES WITH SHALLOW COOL AIRMASS MOVING INTO THE EASTERN PLAINS AS EAST TO SOUTHEAST LOW LEVEL UPSLOPE DEVELOPS WITH SFC HIGH PRESSURE CONTINUING TO BUILD ACROSS CENTRAL KANSAS AND INTO SOUTHERN HIGH PLAINS. MODEL SOUNDINGS INDICATING INVERSIONS REMAINING IN PLACE...ESPECIALLY ALONG THE LOWER ARKANSAS RIVER VALLEY...LIMITING THE AMOUNT MIXING OF THE WARMER AIR ALOFT. WITH THAT SAID...HAVE UNDERCUT GUIDANCE TEMPS ACROSS THE FAR EASTERN PLAINS TODAY KEEPING THE WARMEST READINGS ALONG AND WEST OF THE I-25 CORRIDOR. OUT WEST...EXPECTING HIGHS AT OR SLIGHTLY ABOVE YESTERDAYS READINGS WITH CONTINUED DRY WEATHER AS SLIGHT WARMING CONTINUES WITH BUILDING UPPER RIDGE. EXPECTING MILD OVERNIGHT LOWS AGAIN TONIGHT AND HAVE INCREASED CURRENT LOW TEMPERATURE GRID...ESPECIALLY ALONG THE LOWER EASTERN SLOPES AND IMMEDIATE ADJACENT PLAINS...AS WARM AIR ALOFT PERSISTS WITH BUILDING HEIGHTS AS CENTER OF UPPER HIGH MOVES INTO EASTERN UTAH. -MW .LONG TERM... (TUESDAY THROUGH SUNDAY) ...QUIET WEATHER PATTERN THIS WEEK...WITH WELL ABOVE AVERAGE TEMPERATURES EXPECTED TUESDAY AND WEDNESDAY... HIGH PRESSURE OVER THE GREAT BASIN AND ROCKIES WILL RESULT IN RECORD OR NEAR RECORD HIGH TEMPERATURES OVER SOUTHERN COLORADO ON TUESDAY. WEDNESDAY WILL BE A LITTLE COOLER BUT STILL WARM. THURSDAY THROUGH THE WEEKEND WILL BE COOLER BUT TEMPERATURES WILL STILL BE NEAR OR A LITTLE ABOVE AVERAGE LEVELS. ON TUESDAY...HIGH PRESSURE OVER THE ROCKIES WILL FORCE THE AIR DOWNSLOPE TOWARD LOW PRESSURE OVER THE PLAINS. THE RESULT WILL BE WARM...DOWNSLOPE WINDS BRINGING RECORD HIGH TEMPERATURES TO MUCH OF SOUTHERN COLORADO. TEMPERATURES WILL APPROACH 80 OVER PARTS OF THE PLAINS...WITH MAINLY 60S TO AROUND 70 HIGH VALLEYS...AND MAINLY 50S MOUNTAINS. WEDNESDAY...SURFACE HIGH PRESSURE WILL MOVE SOUTH THROUGH THE CENTRAL PLAINS...REVERSING THE SURFACE GRADIENT OVER EASTERN COLORADO TO UPSLOPE. THIS WILL LIKELY TAKE HIGH TEMPERATURES DOWN A NOTCH...BUT THEY WILL STILL BE WELL ABOVE AVERAGE FOR THIS TIME OF YEAR. MORE DRAMATIC COOLING IS EXPECTED ON THURSDAY WITH HIGHS DROPPING BACK PRETTY CLOSE TO AVERAGE. COULD EVEN POSSIBLY BE SOME LOW CLOUDS TO DEAL WITH ACROSS THE PLAINS EARLY THURSDAY. FRIDAY STILL LOOKS COOL...MAYBE A TAD WARMER...BUT WITH LOW LEVEL UPSLOPE FLOW CONTINUING. IF CURRENT MODELS ARE CORRECT...WE COULD SEE A GOOD REBOUND IN TEMPERATURES AGAIN OVER THE WEEKEND. HOWEVER...PREVIOUS MODEL RUNS HAD A PRETTY SIGNIFICANT SHORTWAVE MOVING THROUGH WHICH IS NOW GONE. IT COULD COME BACK. STAY TUNED. LW && .AVIATION...VFR CONDITIONS EXPECTED TO CONTINUE THROUGH TONIGHT. A DRY COLD FRONT CONTINUES TO MOVE ACROSS THE FAR SE PLAINS EARLY THIS MORNING WITH WEAK LOW LEVEL UPSLOPE DEVELOPING ACROSS THE PLAINS THROUGH THE AFTERNOON. -MW && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/50 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 924 PM EST MON NOV 17 2008 .SYNOPSIS... A LARGE POLAR HIGH PRESSURE AREA CENTERED OVER THE GREAT PLAINS WILL DRIFT SOUTHEAST...AND BE REINFORCED BY ANOTHER SIMILAR HIGH THURSDAY. OUR REGION WILL REMAIN IN A COLD NORTH TO NORTHWEST FLOW MUCH OF THE WEEK. A COUPLE OF WEAK DISTURBANCES WILL AFFECT THE REGION MODULATING CLOUDS...LAKE EFFECT SNOWS NEAR THE GREAT LAKES AND PRODUCING SCATTERED SNOW SHOWERS ELSEWHERE. THESE WILL INCLUDE A WEAK COLD FRONT TONIGHT...AND CLIPPER LOWS MOVING THROUGH THE GREAT LAKES WEDNESDAY NIGHT AND THURSDAY...AND AGAIN SUNDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HAVE ADJUSTED POPS...WX AND TEMPS BASED ON CURRENT TRENDS. ALTHOUGH BULK OF LAKE EFFECT OVER FOR THIS ROUND TRAJECTORY STILL FAVORS A COUPLE OF BANDS DOWN THE MOHAWK VALLEY THIS EVENING INTO SOUTHERN HERKIMER...MONTGOMERY AND FULTON COUNTIES AS WELL AS ANOTHER BAND INTO NORTHERN CATSKILLS. THIS ACTIVITY SHOULD CONTINUE UNTIL A LITTLE AFTER MIDNIGHT WHEN FLOW BECOMES MORE NORTHERLY WITH STILL SOME UPSLOPE ACROSS THE CATSKILLS WHERE WE WILL HOLD SCATTERED POPS. LATEST RUC13 DOES SUGGEST ANOTHER WEAK CONVERGENCE BAND DEVELOPING ALONG LAKE CHAMPLAIN VALLEY AND APPROACHING THE DAKS AND UPPER PORTIONS OF THE HUDSON VALLEY. SO WILL ADD LOW POPS FOR THE DACKS AND NORTHERN WARREN/WASHINGTON COUNTIES OVERNIGHT. VARIABLE DEGREES OF CLOUDS OVERNIGHT WHICH WILL PLAY HAVOC WITH OVERNIGHT LOWS. UPSTREAM DEWPOINTS ARE RUNNING A COUPLE DEGREES COOLER THAN GUIDANCE AND THE LATEST LAMP SEEMS TO BE LATCHING ONTO THIS WITH A BIT LOWER LOWS OVERNIGHT. SO WILL FAVOR THE MET/WRF- MET GUIDANCE WHICH IS LOWER THAN FWC/MAV. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/... SERIES OF 500HPA SHORT WAVES DIVE INTO TROF ACROSS THE NORTHEAST DIG/DEEPEN THE TROF AND CUT IT OFF DELMARVA BY 00UTC WED. THIS OCCURS WELL SOUTH OF FCA...AND ONLY REAL IMPACTS OVER FCA IS SOME SCT -SHSN WITH SHORT WAVES PASSING THROUGH FCA AS PART OF THIS PROCESS. THIS MAY BE ENHANCED BY THE COLD MOIST CYCLONIC FLOW ACROSS THE FCA...AND POSSIBLY TRRN. CAA CONTINUES AS FCA IS IN COLDEST AIR OVER LOWER 48 WITH 500-1000DM THICKNESS VALUES 510-520DM. AT SAME TIME 1ST SFC HIGH IS BUILDING EAST FROM GRTLKS...AND SFC FLOW TURNS N. WITH SUCH COLD AIRMASS AND THE WIND GRADIENT IT WILL MAKE IT FEEL EVEN COLDER. THIS SFC FLOW AND THE MID LEVEL 500HPA TROF POSITION WILL SHIFT THE GRTLKS BASED LAKE EFFECT WEST OF FCA...BUT MAY GET A RESPONSE OFF LAKE CHAMPLAIN AND LAKE GEORGE OVER EXTREME ENY. TUES NT THIS WHOLE SYSTEM SLIDES OFFSHORE AND SFC HIGH BUILDS EAST. WITH RIDGING AT ALL LEVELS...FAIR SKIES TEMPS SHOULD IDEALLY RADIATE. WED SFC RIDGE AXIS MOVES ACROSS FCA...AND ON ITS WEST SIDE WAA AHEAD OF A CLIPPER LOW IN THE UPPER GRTLKS REGION INCREASES MID/HIGH CLOUDS...WHICH PERSIST WED NT. THURSDAY CLIPPER SFC LOW MOVES EAST FM EASTERN GRTLKS AND EXITS REGION DRAGGING CDFNT AND NEXT SURGE OF CAA THROUGH REGION. FLOW AT 500 HPA REMAINS BROADLY CYCLONIC OVER EASTERN HALF OF NA...AND LAKE RESPONSE THAT DOES AFFECT THE REGION WILL BE ALONG SW PERIPHERY THU NT(W MHWK VLY AND W CATSKILLS). && .LONG TERM /FRIDAY THROUGH MONDAY/... AT THE START OF THE LONG TERM PERIOD...A LARGE UPPER LEVEL TROUGH WILL BE SITUATED OVER THE NORTHEAST. UPPER LEVEL TEMPS WILL CONTINUE TO BE QUITE COLD FOR FRIDAY AND SATURDAY...AS 850 MB TEMPS OF -12 TO -16 C /ABOUT 1-2 STD BELOW NORMAL/ WILL ONLY ALLOW FOR MAX TEMPS TO REACH THE MIDDLE 30S IN THE VALLEYS. SOME LAKE EFFECT MAY SNEAK INTO WESTERN PARTS OF THE ADIRONDACKS AND UPPER MOHAWK VALLEY...AND THE CYCLONIC UPSLOPE FLOW MAY ALSO ALLOW FOR SOME SNOW SHOWERS ACROSS PARTS OF THE CATSKILLS AS WELL. WEAK RIDGING WILL BUILD INTO THE REGION FOR EARLY ON SUNDAY. THIS SHOULD ALLOW FOR AT LEAST THE FIRST HALF OF THE DAY TO REMAIN DRY CWA WIDE. THE CORE OF THE COLD WILL SHIFT NORTHEASTWARD...AS 850 MB TEMPS WILL BE SOMEWHAT WARMER FOR SUNDAY /ONLY -6 TO -11 DEGREES C/...SO HIGH TEMPS MAY BE A FEW DEGREES WARMER FOR SUNDAY. THE 12Z OPERATIONAL RUNS OF THE ECMWF AND GFS DIVERGE AT THIS POINT. WHILE THE GFS BRINGS A WEAK CLIPPER ACROSS THE REGION FROM THE NORTHERN STREAM FOR SUNDAY NIGHT WITH A LIGHT SNOWFALL TO THE REGION. MEANWHILE...THE ECMWF IS DELAYED WITH THIS SYSTEM...AS IT CUTS IT OFF ACROSS THE UPPER MIDWEST. THE ECMWF EVENTUALLY PHASES THIS SYSTEM WITH SOME SOUTHERN STREAM ENERGY MOVING ACROSS THE SOUTHERN PLAINS...AND TRIES TO BRING A COMPLEX WINTER STORM TO THE REGION FROM THE OHIO VALLEY FOR MONDAY INTO TUESDAY. THE 12Z MREF PLUMES SHOW QUITE A DEAL OF SPREAD IN THE TIMING AND QPF OF ANY SYSTEM DURING THE SUN-TUE TIME PERIOD AS WELL. AT THIS POINT...WILL ONLY ADD LOW CHC POPS FOR THE PERIOD AND CONTINUE TO MONITOR TRENDS. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... THE LAKE EFFECT SNOW SHOWERS THAT IMPACTED THE AREA EARLIER THIS AFTERNOON HAVE DIMINISHED CONSIDERABLY DURING THE LAST SEVERAL HOURS ACROSS THE FA. VFR CONDITIONS ARE EXPECTED ACROSS THE TAF SITES THROUGH 00Z WED ALTHOUGH CLOUDS WILL PERSIST MUCH OF THE TIME AS UPPER TROF AND ASSOCIATED VORT AXIS SWINGS THROUGH THE REGION. WINDS WILL GENERALLY BE LIGHT AND VARIABLE OVERNIGHT WITH NORTH WINDS 6-12 KTS EXPECTED ON TUESDAY. OUTLOOK... TUE NIGHT-WED...VFR...NO SIG WX. THU...VFR/MVFR...SLGT CHC/CHC SHSN/RA. FRI- SAT...VFR...NO SIG WX. && .HYDROLOGY... COLD AND MORE SEASONABLE AIRMASS IN PLACE ACROSS REGION NOW. LAKE EFFECT SNOW SHOWERS WILL DIMINISH TONIGHT AS THE FLOW BECOME MORE NORTHERLY. NO SIGNIFICANT PRECIPITATION IS EXPECTED OVER THE NEXT FEW DAYS. PORTIONS OF THE ADIRONDACKS DID RECEIVE AROUND ONE HALF INCH OF WATER EQUIVALENT THE PAST 24 HOURS. HOWEVER...LITTLE OR NO SNOW MELT IS ANTICIPATED DUE TO EXPECTED COLD TEMPERATURES. NEXT CHANCE FOR SIGNIFICANT WIDESPREAD PRECIPITATION MAY BE NEXT WEEK. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...SNYDER NEAR TERM...BGM/11 SHORT TERM...SNYDER LONG TERM...FRUGIS AVIATION...11 HYDROLOGY...DIRIENZO/BGM ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 336 PM EST SUN NOV 16 2008 .SYNOPSIS... A RETURN TO MORE SEASONABLE WEATHER...PERHAPS A BIT BELOW NORMAL...FOR MOST OF THIS UPCOMING WEEK. THIS COLD AIR MOVING ACROSS LAKE ONTARIO WILL RESULT IN LAKE EFFECT SNOW FOR PORTIONS OF THE REGION AS WE START THE WORK WEEK. ANOTHER DISTURBANCE IS EXPECTED TO IMPACT THE REGION TOWARD THE END OF THE WEEK WITH ANOTHER CHANCE FOR SNOW FOR THE ENTIRE REGION. && .NEAR TERM /THROUGH TONIGHT/... MOST OF THE ATTENTION FOR THIS FORECAST PERIOD REVOLVES AROUND LAKE EFFECT SNOW. LOW LEVEL CONVERGENCE SIGNATURE FROM THE RUC13/NAM12/HRRR-RUC ALL SUGGEST THE BANDS OFF LAKE ONTARIO WILL CONSOLIDATE OVER OSWEGO COUNTY AND WITH 270-280 FLOW IN THE BOUNDARY LAYER WITH SHORT WAVE TROUGH AXIS TAKING A SOUTHERN ROUTE ACROSS PA...SEEMS IDEAL CONDITIONS FOR A MODERATE TO PERHAPS HEAVY BAND OF CONVECTION WITH HIGH INVERSION LEVELS. IN FACT...EQUILIBRIUM LEVELS ARE EXPECTED TO BE NEAR 12K FEET WHERE -25C ISOTHERM IS EXPECTED. WITH CONTINUED COOLING IN THE COLUMN...WOULD NOT SURPRISED TO SEE SOME LIGHTNING TONIGHT LEE OF THE LAKE AND SOME RUMBLES OF THUNDER INTO OUR WESTERN CWA. SNOWFALL AMOUNTS IN THE WESTERN MOHAWK VALLEY AND THE DACKS MAY ADD UP TO 6 INCHES IN THE ADVISORY AREA AND NO ADJUSTMENTS NEEDED AT THIS TIME. WILL CONTINUE TO MAKE MENTION THAT THE NY STATE THRUWAY IMPACTS LATER TONIGHT IN THE WSW. THIS MOISTURE WILL STREAM ACROSS THE NORTHERN HALF OF THE CWA WITH COMPLEX TERRAIN AND INTO WESTERN NEW ENGLAND. HERE ANOTHER RISE IS EXPECTED INTO THE SOUTHERN GREEN MOUNTAINS WHERE SOME LIGHT AMOUNTS OF SNOW ARE EXPECTED /PERHAPS UP TO 2 INCHES IN THE HIGHER ELEVATIONS/. AS THE BAND SLOWLY DRIFTS SOUTH OVERNIGHT...THE CAPITAL REGION AND THE BERKS MAY SEE A LITTLE SNOW WITH ACCUMS LESS THAN 1 INCH EXPECTED. && .SHORT TERM /MONDAY THROUGH TUESDAY/... AS THE AFOREMENTIONED WAVE TAKES THE SOUTHERN ROUTE ON MONDAY...BOUNDARY LAYER FLOW BECOMES MORE NORTHWEST. THIS WILL SHIFT THE LAKE EFFECT BAND SOUTH OF THE THRUWAY BY EARLY AFTERNOON WITH A MULTI-BAND SETUP. SOME ADDITIONAL UPSLOPE ACROSS THE CATSKILLS COULD SQUEEZE OUT ADDITIONAL SNOW/RAIN-SNOW MIX THROUGH THE REMAINDER OF THE DAY. WITH CHILLY TEMPERATURES ALOFT AND IMPRESSIVE MIXING LAYER HEIGHT DEPTH...40-45F FOR HIGHS IN THE VALLEY WITH 30S ELSEWHERE. THIS WILL RESULT IN A VARIETY OF PRECIP TYPES WHICH WILL BE HIGHLY DEPENDANT ON TEMPS AND ELEVATION. THE ENTIRE UPPER TROUGH SWINGS ACROSS THE REGION MONDAY NIGHT WITH SOME INDICATIONS OF DPVA AND FAIRLY MOIST PROFILE. WILL INCLUDE A LITTLE HIGHER POPS FOR SNOW SHOWERS TO THE ENTIRE CWA. TEMPERATURES OVERNIGHT WILL BE IN THE 20S. THIS TROUGH SLOWLY MIGRATES TO THE EAST BUT STILL IN THE VICINITY. THIS WILL KEEP THE CLOUD COVER IN PLACE WITH THE CHANCE OF FLURRIES/LIGHT-SNOW SHOWERS FOR THE ENTIRE REGION AS TEMPERATURES ONLY MAX OUT INTO THE MIDDLE 30S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM PERIOD WILL BEGIN WILL A LARGE WELL AMPLIFIED UPPER TROUGH SITTING OVER THE NORTHEASTERN PORTION OF THE CONUS. THE UPPER TROUGH AXIS WILL SLOWLY BE MOVING EASTWARD ON TUESDAY NIGHT. VERY COLD AIR /850 MB TEMPS AS COLD AS -16 C/ WILL BE OVER THE REGION...WHICH WILL ALLOW FOR WELL BELOW NORMAL MIN TEMPS...WITH TEENS TO BARELY THE LOWER 20S IN MOST AREAS. WITH THE SFC-700 MB FLOW EXPECTED TO BE 320-340 DEGREES...WOULD EXPECT FOR ANY LAKE EFFECT ACTIVITY TO BE SITUATED TO THE WEST OF THE CWA. WEAK HIGH PRESSURE MAY NOSE UP FROM THE MID ATLANTIC STATES FOR WEDNESDAY...KEEPING IT PRECIP FREE ACROSS THE CWA. DESPITE THE CORE OF THE COLD AIR LIFTING NORTHEASTWARD...850 MB TEMPS WILL CONTINUE TO RUN 2-3 STD BELOW NORMAL ACCORDING TO THE GEFS CONSENSUS...WHICH WILL ONLY ALLOW FOR HIGH TEMPS IN THE LOWER TO MIDDLE 30S ACROSS VALLEY LOCATIONS. BY LATE WEDNESDAY NIGHT INTO THURSDAY...A CLIPPER SYSTEM WILL BE DIVING SOUTHEASTWARD ACROSS UPSTATE WESTERN NY AND INTO CENTRAL PA. THIS SYSTEM LOOKS TO STAY FAIRLY MOISTURE STARVED...BUT WILL STILL BRING THE POTENTIAL FOR SOME LIGHT PRECIP...MAINLY IN THE FORM OF SNOW...TO WESTERN AND SOUTHERN PARTS OF THE CWA...AS IT WILL SLIDE CLOSER TO THE BAROCLINIC ZONE LOCATED TO OUR SOUTH. HAVE GONE WITH CHC POPS OVER THESE AREAS TO ACCOUNT FOR THIS POSSIBILITY. THE LATEST 12Z OPERATIONAL RUNS OF THE ECMWF AND GFS DIVERGE ON THE DETAILS FOR FRIDAY THROUGH SUNDAY. THE ECMWF SHOWS A FAST MOVING PROGRESSIVE TROUGH MOVING ACROSS THE NORTHEAST ON FRIDAY...WITH THE FLOW BECOMING MORE ZONAL BY SAT NIGHT/SUNDAY....BEFORE YET ANOTHER SHORTWAVE TROUGH MOVES TOWARDS THE REGION FOR LATE SUNDAY INTO MONDAY. THIS MAY BRING A CHC FOR LIGHT SNOW LATE SUNDAY AS THE AIR ALOFT REMAINS ANOMALOUSLY COLD. MEANWHILE...THE 12Z GFS SHOWS THE UPPER TROUGH CLOSING OFF ACROSS NEW ENGLAND OVER THE WEEKEND...WITH SURFACE CYCLOGENESIS TAKING PLACE OFF THE MID ATLANTIC COAST. IN THE SCENARIO...WE WOULD BE DEALING WITH A FULL OUT SNOWSTORM FOR MUCH OF THE AREA. BEFORE GETTING TOO EXCITED...IT/S IMPORTANT TO NOTE THAT THE 12Z GEFS PLUMES SHOW QUITE A DEAL OF SPREAD REGARDING QPF AND EVEN PRECIP TYPE AS WELL FOR ANY POTENTIAL SYSTEM OVER THE WEEKEND. ITS ALSO WORTH MENTIONING THAT THERE HAS BEEN LITTLE RUN TO RUN CONSISTENCY /AS WOULD BE EXPECTED THIS FAR OUT/ REGARDING THIS SYSTEM. WILL PLAY THE FORECAST AS LOW CHC POPS FOR THE WEEKEND FOR MAINLY SNOW...BUT WILL HAVE TO WATCH THE EVOLUTION OF ANY SYSTEM THROUGHOUT THE WEEK TO CARVE OUT OF THE DETAILS. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... STRONG GUSTY WINDS WILL CONTINUE AS THE TIGHT PRESSURE GRADIENT REMAINS OVER THE AREA. WINDS GUSTS EXPECTED TO BE 30-37KTS. VFR CONDITIONS WILL PERSIST THROUGH THE AFTERNOON WITH CIGS 3500-5000FT. LAKE EFFECT WILL CONTINUE OFF OF LAKE ONTARIO...MAINLY AFFECTING THE ADIRONDACKS. ANY SNOW THAT DOES CHANNEL DOWN THE MOHAWK WILL BE LIGHT WITH ONLY A DUSTING EXPECTED AT KALB. KGFL MAY HAVE A FLURRY OR TWO AS WELL. HAVE INCLUDED VCSH AT KALB AND KGFL THROUGH 05Z. AT THAT TIME...WINDS WILL SHIFT WEST SOUTHWEST...KEEPING THE LAKE EFFECT CONCENTRATED IN THE ADIRONDACKS OF HERKIMER...HAMILTON...AND NORTHWESTERN FULTON COUNTIES. WINDS WILL PICK UP IN THE MID MORNING AT 8-12 KTS OUT OF THE WEST. OUTLOOK... MON...VFR...CHC MVFR IN SCT -SHSN ESP WEST OF HUDSON VALLEY. TUE...VFR...ISOLATED -SHSN. WED...VFR...NO SIG WX. THU...VFR/MVFR...SLGT CHC/CHC -SHSN/-SHRA. FRI...VFR...NO SIG WX. && .HYDROLOGY... RAINFALL AMOUNTS WERE LESS THAN ANTICIPATED YESTERDAY OVER MOST OF THE REGION. THE PRIMARY EXCEPTION WAS THE WESTERN ADIRONDACKS WHERE ONE TO TWO INCHES OF RAIN FELL...ALONG WITH A SMALL PATCH OF THE HIGHER ELEVATIONS OF THE CATSKILLS. THE MOOSE RIVER IN HERKIMER COUNTY CAME UP THREE FEET SINCE YESTERDAY AFTERNOON BUT WAS NEAR ITS PEAK AND IT WILL ONLY RISE A FEW INCHES EARLY THIS AFTERNOON. THE WEST CANADA ABOVE HINCKLEY RESERVOIR ALSO CAME UP ALMOST TWO FEET AS DID THE HEADWATERS OF THE MOHAWK RIVER. THIS FLOW WILL MAKE ITS WAY TO THE CAPITAL DISTRICT LATER TODAY AND THIS EVENING...CAUSING THE MOHAWK TO RISE ABOUT ANOTHER SIX TO EIGHT INCHES AT SCHENECTADY AND ANOTHER FOOT AT COHOES...WHICH WILL BRING THE HUDSON UP A FEW INCHES UPSTREAM OF THE TROY DAM. RAIN OVER THE HOUSATONIC BASIN WAS LIGHT AND IT WILL ONLY RISE A FEW INCHES. MUCH COLDER AIR WILL POUR INTO THE REGION TODAY. THE PRIMARY PTYPE TONIGHT THRU THE WEEK WILL BE SNOW. LAKE ENHANCED SNOW SHOWERS WILL PERSIST TONIGHT INTO TUESDAY...BUT THESE WILL HAVE NO IMMEDIATE EFFECT ON THE RIVERS. COOLER TEMPERATURES WILL ALLOW RIVERS AND STREAMS TO RECEDE FAIRLY QUICKLY FROM THE RAIN YESTERDAY...WITH NO SIGNIFICANT RAIN THROUGH THE REST OF THE WEEK. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST MONDAY FOR NYZ032-033-038-082. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...KGS HYDROLOGY...RCK FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 855 AM EST SUN NOV 16 2008 .UPDATE...THE LATEST WATER VAPOR/H5 RUC ANALYSIS DEPICTS A HIGHLY AMPLIFIED UPPER PATTERN ACROSS THE LOWER 48 THIS MORNING...WITH A LONG WAVE RIDGE ALONG THE PACIFIC COAST AND A NEGATIVELY-TILTED TROUGH OVER THE ERN CONUS. THE TROUGH AXIS SHIFTED NE OF THE CWA DURING THE PRE-DAWN HOURS...WITH W-NWLY FLOW THROUGH THE COLUMN. MUCH DRIER AIR IN THE MID/UPPER LEVELS OF THE ATMOSPHERE IS SURGING EWD BEHIND THE TROUGH AXIS...WITH REGIONAL 12Z SOUNDING PRECIP WATER VALUES FROM 0.25-0.35 INCHES. CANADIAN HIGH PRESSURE SITUATED OVER LA/COASTAL TX HAS A RIDGE EXTENDING NE AND E INTO THE DEEP SOUTH AND ALONG THE GULF COAST. A SURFACE TROUGH LOCATED ALONG THE LEE SIDE OF THE CNTRL/SRN APPALACHIANS...AND COLD FRONTS OFF THE SRN ATLANTIC COAST AND ACROSS CUBA. SKIES ACROSS THE CWA WERE CLEAR...WITH COLD ADVECTION STRATOCU STREAKING SWD OVER THE WARMER GULF WATERS...AND LOW CLOUDS THROUGHOUT THE OH/TN VALLEYS. FOR THE REST OF TODAY...EXPECT MOSTLY SUNNY SKIES. MORNING 850 TEMPS FROM 2-4 DEG C SUPPORT AFTN HIGHS IN THE UPPER 50S TO LOWER 60S...AS ADVERTISED IN THE MORNING ZONE FCST. MIXING OF 20-25 KTS WINDS IN THE BOUNDARY LAYER WILL INCREASE WINDS TO 10-15 MPH BY LATE MORNING. ASIDE FROM NUDGING WINDS UP SLIGHTLY...NO OTHER CHANGES ARE PLANNED. && .AVIATION...VFR THROUGH THE FORECAST PERIOD. NORTHWEST WINDS 10 TO 15 KT WITH GUSTS TO 20 KT THIS MORNING WILL DIMINISH TO 5 KT OR LESS BY THIS EVENING...AND BECOME NEAR CALM OVERNIGHT. && .MARINE...OBS TRENDS THE PAST FEW HOURS HAVE CHANGED LITTLE...WITH NLY WINDS AROUND 20 KTS WITH GUSTS TO 25 KTS AND SEAS FROM 7-9 FT AT THE BUOYS. AT THE MOB BUOY...WINDS AND SEAS HAVE DIMINISHED TO EXERCISE CAUTION CRITERIA (15-20 KTS AND 5-6 FT SEAS). THE TIGHT PRESSURE GRADIENT COMBINED WITH COLD AIR ADVECTION WILL MAINTAIN SMALL CRAFT ADVISORY CONDITIONS THIS MORNING. AS THE SURFACE RIDGE BUILDS FURTHER EASTWARD ALONG THE NRN GULF COAST...THE GRADIENT08Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW A HIGHLY AMPLIFIED UPPER PATTERN ACROSS THE NATION EARLY THIS MORNING WITH LONGWAVE RIDGING ALONG THE PACIFIC COAST AND INTER-MOUNTAIN WEST...AND LONGWAVE AND DEEP TROUGHING FURTHER DOWNSTREAM ACROSS THE EASTERN HALF OF THE NATION. WILL RELAX THIS AFTERNOON. WINDS AND SEAS WILL FALL BELOW ADVISORY CRITERIA OVER THE NEAR SHORE WATERS EARLY THIS AFTERNOON AND OVER THE OFFSHORE WATERS BY THIS EVENING. ONLY MINOR TWEAKING OF THE WINDS AND SEAS ARE ANTICIPATED FOR THE MORNING FCST UPDATE. && .FIRE WEATHER...THE RED FLAG WARNING REMAINS IN EFFECT FOR THIS AFTERNOON AND THE FIRE WEATHER WATCH FOR MONDAY AFTERNOON. IT STILL LOOKS LIKE RED FLAG CONDITIONS WILL BE POSSIBLE BOTH TUESDAY AND WEDNESDAY AFTERNOONS...ESPECIALLY IN OUR FL ZONES. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 60 32 65 40 62 / 0 0 0 0 0 PANAMA CITY 60 39 65 43 64 / 0 0 0 0 0 DOTHAN 59 35 65 38 59 / 0 0 0 0 0 ALBANY 59 34 65 37 59 / 0 0 0 0 0 VALDOSTA 60 33 65 38 59 / 0 0 0 0 0 CROSS CITY 63 32 68 38 64 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING FROM NOON EST /11 AM CST/ THIS MORNING TO 6 PM EST /5 PM CST/ THIS AFTERNOON FOR ALL OF THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND. FIRE WEATHER WATCH MONDAY AFTERNOON FOR ALL OF THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND. GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR THE THE NEAR SHORE MARINE ZONES FROM DESTIN FLORIDA EASTWARD TO THE MOUTH OF THE SUWANNEE RIVER OUT TO 20 NM. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR THE OFFSHORE MARINE ZONES FROM DESTIN FLORIDA EASTWARD TO THE MOUTH OF THE SUWANNEE RIVER EXTENDING FROM 20 TO 60 NM OFFSHORE. && $$ JAMSKI/BLOCK fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 320 AM EST SUN NOV 16 2008 .SYNOPSIS... 08Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW A HIGHLY AMPLIFIED UPPER PATTERN ACROSS THE NATION EARLY THIS MORNING WITH LONGWAVE RIDGING ALONG THE PACIFIC COAST AND INTER-MOUNTAIN WEST...AND LONGWAVE AND DEEP TROUGHING FURTHER DOWNSTREAM ACROSS THE EASTERN HALF OF THE NATION. THE BASE OF THE EASTERN U.S. TROUGH CURRENTLY CROSSING THE FORECAST AREA EARLY THIS MORNING ALONG WITH THE CORE OF THE MID LEVEL COLD POOL. 850MB TEMPERATURES ARE CURRENTLY AROUND -2C OVER THE FAR NORTHERN ZONES TO AROUND ZERO C OVER THE COAST. WV IMAGERY SHOWING A VERY DRY ZONE OF MID/UPPER LEVEL AIR ROUNDING THE BASE OF THE TROUGH. THIS VERY DRY AIR IS WELL SAMPLED ON THIS PAST EVENING`S KTLH SOUNDING SHOWING A PW THROUGH THE COLUMN OF ONLY 0.3" WHICH IS ONLY ONE THIRD OF THE NORMAL VALUE FOR MID NOVEMBER. IF FACT DEWPOINT DEPRESSIONS ABOVE 850MB ARE ON AVERAGE AROUND 30C WITH VALUES APPROACHING 50C AT 700MB. AT THE SURFACE...FORECAST AREA RESIDES ON THE FAR EASTERN EDGES OF STRONG 1030MB HIGH PRESSURE CENTERED ACROSS EASTERN TEXAS. A VERY TIGHT GRADIENT REMAINS IN PLACE BETWEEN THIS HIGH AND SATURDAY`S COLD FRONT RESULTING IN STEADY NORTHWEST WINDS. THE TIGHT GRADIENT AND STRONG COLD AIR ADVECTION IS RESULTING IN SOLID ADVISORY LEVEL WINDS OVER THE MARINE AREA WITH GUSTS CONSISTENTLY AROUND 30 KNOTS. THESE STRONG WINDS HAVE REALLY WHIPPED UP THE SEAS WITH WAVE HEIGHTS OF 8 TO 10 FEET BEING REPORTED AT THE BUOYS SOUTH OF PANAMA CITY AND APALACHICOLA. SKIES ARE MOSTLY CLEAR ACROSS MOST OF OUR LAND ZONES...HOWEVER HAVE DEVELOPED AN EXPANSIVE AREA OF STRATACU OVER THE OFFSHORE WATERS AS THE COLD AND DRY AIRMASS MOVES SOUTH ACROSS THE RELATIVELY WARM GULF OF MEXICO WATERS. TEMPERATURES THIS MORNING DROPPING INTO THE LOWER 40S NORTH AND THE MIDDLE 40S SOUTH. SHOULD DROP SEVERAL MORE DEGREES BEFORE SUNRISE. && .SHORT TERM... (TODAY THROUGH TUESDAY) LONGWAVE TROUGHING WILL BE THE GENERAL RULE ACROSS THE EASTERN HALF OF THE NATION THROUGH THE SHORT TERM PERIOD. SHARP TROUGH AXIS SWINGING ACROSS THE FORECAST EARLY THIS MORNING WILL RAPIDLY EXIT TO THE NORTHEAST WHILE DE-AMPLIFYING INTO THE EARLY AFTERNOON HOURS. AS THIS TROUGH AXIS RETREATS IT WILL TAKE THE MID-LEVEL COLD POOL WITH IT ALLOWING THE OVERALL AIRMASS TO BEGIN TO RECOVER THROUGH THE DAY. 850MB TEMPS RISING TO BETWEEN +5 AND +7C BY THIS EVENING. HOWEVER...EVEN WITH THIS RECOVERY AND DESPITE ABUNDANT SUNSHINE...WILL BE DEALING WITH AFTERNOON TEMPERATURES AROUND 10 DEGREES BELOW AVERAGE. AFTER A COOL START IN THE MIDDLE 30S TO LOWER 40S...OUR ALABAMA AND GEORGIA ZONES STRUGGLE TO RISE INTO THE UPPER 50S TO NEAR 60 AND INTO THE LOWER 60S FOR OUR FLORIDA ZONES. SURFACE RIDGE WELL TO OUR WEST WILL BEGIN TO BUILD EASTWARD ALONG THE NORTHERN GULF COAST ALLOWING THE WINDS TO SETTLE A BIT THROUGH THE DAYLIGHT HOURS. SURFACE RIDGE AXIS BUILDS OVERHEAD TONIGHT ALLOWING SURFACE WINDS TO BECOME VERY LIGHT OR EVEN CALM IN SHELTERED LOCATIONS. THESE LIGHT WINDS...DRY CONDITIONS AND MOSTLY CLEAR SKIES WILL RESULT IN A GOOD RADIATIONAL COOLING SETUP. THE AIRMASS AS A WHOLE WILL BE SLOWLY RECOVERING...BUT HAVE SEEN TIME AND AGAIN THAT THESE RADIATIONAL COOLING NIGHTS CAN OVERCOME THIS RECOVERY AND RESULT IN COOLER TEMPS THAN WOULD OTHERWISE BE EXPECTED. THEREFORE CURRENT GRIDS SHOW WIDESPREAD TEMPERATURES FALLING INTO THE LOWER AND MIDDLE 30S TOWARD SUNRISE ON MONDAY WITH THE NORMALLY COLDEST INLAND SPOTS DROPPING A DEGREE OR TWO BELOW THE FREEZING MARK. URBAN CENTERS AND ALONG THE IMMEDIATE COAST ARE MORE LIKELY TO HOLD IN THE MIDDLE TO UPPER 30S. IT WOULD APPEAR AT THIS TIME THAT THE MOST LIKELY AREAS TO SEE TEMPERATURES BRIEFLY REACH THE FREEZING MARK WOULD BE ALONG AND SOUTH OF THE I-10 CORRIDOR (BUT AWAY FROM THE IMMEDIATE COAST) WHERE SANDIER SOILS WILL FURTHER AID THE COOLING. THE LIGHTER WINDS SHOULD RESULT IN THE FORMATION OF SOME PATCHY FROST DURING THE LATE NIGHT HOURS. WILL CONTINUE WITH PATCHY FROST MENTION BETWEEN ROUGHLY 5AM AND 8AM MONDAY MORNING FOR THOSE INLAND AREAS EXPECTED TO REACH THE MIDDLE 30S OR LOWER. PERSONS WITH SENSITIVE OUTDOOR VEGETATION SHOULD CONTINUE TO PAY CLOSE ATTENTION TO FORECAST UPDATES THROUGH TODAY IN CASE ADDITIONAL PRECAUTIONS BECOME NECESSARY. FAIR WEATHER CONTINUES INTO MONDAY WITH LIGHT WINDS AND MOSTLY SUNNY SKIES. AFTERNOON HIGH TEMPS WILL BE UP A BIT AFTER THE VERY COOL START. A DIURNAL RISE OF 30+ DEGREES WILL RESULT IN WIDESPREAD MIDDLE 60S WITH A FEW SPOTS ACROSS THE SOUTHEAST FL BIG BEND INTO THE UPPER 60S TO NEAR 70. WILL BE WATCHING SHORTWAVE ENERGY MOVING SOUTHEAST OUT OF THE NORTHERN MS VALLEY EARLY IN THE DAY AROUND THE WESTERN PERIPHERY OF THE MAIN EASTERN TROUGH. THIS ENERGY WILL REACH THE OHIO VALLEY/MID ATLANTIC REGION MONDAY AFTERNOON AND EVENING HELPING TO RE-AMPLIFY THE TROUGH ALONG THE EASTERN SEABOARD. IN RESPONSE TO THIS SHARPENING OF THE TROUGH...WILL SEE ANOTHER COLD FRONT SURGE SOUTH ACROSS THE SOUTHEASTERN STATES MONDAY AFTERNOON AND NIGHT. VERY LITTLE MOISTURE FOR THIS BOUNDARY TO WORK WITH SO SHOULD BE DRY WITH ONLY A FEW MID-LEVEL CLOUDS AND A SLIGHT WIND SHIFT TO MARK ITS PASSAGE THROUGH THE AREA MONDAY NIGHT. THIS FRONT WILL BRING ANOTHER UNUSUALLY COOL POLAR AIRMASS TO THE AREA. HIGH TEMPS ON TUESDAY WILL BE BACK DOWN INTO THE UPPER 50S NORTH AND LOWER 60S (AT BEST) IN THE SOUTH AS 850MB TEMPS DROP BACK DOWN TOWARD ZERO C OVER OUR NORTHERN AND ESPECIALLY NORTHEAST ZONES. A STRONG 1033-1035MB HIGH PRESSURE RIDGE WILL BE SETTLING SOUTH THROUGH THE TENNESSEE VALLEY DURING TUESDAY AFTERNOON IN THE WAKE OF THE FRONT. THIS RIDGE IS ANTICIPATED TO CONTINUE BUILDING SOUTH INTO THE SOUTHEASTERN STATES TUESDAY NIGHT SETTING UP ANOTHER GOOD RADIATIONAL COOLING NIGHT. THERE IS INCREASING CONFIDENCE IN THE POTENTIAL FOR A MORE SUBSTANTIAL FREEZE EVENT TUESDAY NIGHT INTO EARLY WEDNESDAY. MORE ABOUT THIS POTENTIAL EVENT IN THE LONG TERM DISCUSSION BELOW. && .LONG TERM... (TUESDAY NIGHT THROUGH SUNDAY) THE GFS...GFS ENSEMBLE MEAN...AND ECMWF ARE IN GOOD AGREEMENT FOR THIS FORECAST CYCLE. THE AMPLIFIED 500 MB PATTERN IS FORECAST TO FLATTEN INTO A MORE ZONAL FLOW BY THE WEEKEND. WE WILL LIKELY HAVE TO CONTEND WITH THE COLDEST MORNING SO FAR THIS SEASON ON WEDNESDAY...AS A HIGH PRESSURE RIDGE SETTLES ACROSS THE SOUTHEAST U.S. AND A COLD DRY AIRMASS ALLOWS FOR STRONG RADIATIONAL COOLING. THERE IS A CHANCE OF A HARD FREEZE IN THE NORMALLY COLDER INLAND LOCATIONS...AS THE BIAS CORRECTED GFS AND NAM OUTPUT ARE EXTREMELY COLD FOR THIS TIME OF YEAR WITH TEMPERATURES IN THE LOWER TO MID 20S AT SOME SITES. WE WILL BLEND THIS GUIDANCE WITH THE SLIGHTLY-WARMER GFS MOS. THERE IS STILL A CHANCE OF A LIGHT FREEZE AND/OR FROST EVENT THURSDAY MORNING IN OUR NORMALLY COLDER INLAND LOCATIONS. MOS AND THE GFS RAW OUTPUT FLIP FLOP THEIR ROLES FOR THE THURSDAY MORNING FORECAST AS THE GFS APPEARS TO BE WARMING THE BOUNDARY LAYER TOO QUICKLY WHILE THE GFS MOS IS PICKING UP ON THE SIGNALS THAT INDICATE A MUCH COLDER NIGHT AS A STABLE NOCTURNAL BOUNDARY LAYER DEVELOPS AND COOLS RAPIDLY. AFTER A BRIEF RETURN TO NEAR-AVERAGE TEMPERATURES THURSDAY AFTERNOON...A DRY COLD FRONT IS FORECAST TO PUSH SOUTH THROUGH THE FORECAST AREA THURSDAY NIGHT AND BRING ANOTHER SHOT AT COLD AIR TO THE REGION FRIDAY MORNING. THE BIAS CORRECTED GFS SOLUTION FORECASTS LOWS NEAR FREEZING FRIDAY AND SATURDAY MORNINGS...WHILE THE GFS MOS (WHICH IS HEAVILY WEIGHTED TOWARD CLIMATOLOGY) IS WARMER. A SLOW RETURN TO MORE AVERAGE TEMPERATURES SEEMS LIKELY ON SUNDAY. THE OPERATIONAL GFS AND A FEW OF THE ENSEMBLE MEMBERS FORECAST SOME RAIN FOR OUR AREA SUNDAY...BUT THE MODEL RH AND MASS FIELDS DO NOT REALLY SUPPORT THIS. && .AVIATION... UNLIMITED CIGS AND VIS ARE EXPECTED ALL DAY AND INTO TONIGHT... BARRING ANY UNEXPECTED LARGE WILD FIRES. NORTHWEST WINDS WILL RANGE FROM 5 TO 10 KT OVERNIGHT...THEN INCREASE TO 10 TO 13 KT WITH GUSTS TO 20 KT BY LATE MORNING...BEFORE DROPPING TO 5 KT OR LESS LATE THIS AFTERNOON OR EARLY EVENING. && .MARINE... A TIGHT GRADIENT COMBINED WITH CONTINUED COLD AIR ADVECTION WILL KEEP NORTHERNLY WINDS AND SEAS ABOVE ADVISORY LEVELS THROUGH THE MORNING HOURS TODAY. SURFACE RIDGING WILL BEGINS TO BUILD EASTWARD ALONG THE NORTHERN GULF COAST THROUGH THE DAY AND HELP TO RELAX THE GRADIENT INTO THE AFTERNOON HOURS. SHOULD SEE WINDS DROP BELOW ADVISORY LEVELS OVER THE NEAR SHORE WATERS DURING THE EARLY AFTERNOON AND OVER THE OFFSHORE WATERS BY EARLY THIS EVENING. NORTHERLY FLOW CONTINUES INTO MONDAY...BUT GENERALLY REMAINING BELOW HEADLINE CRITERIA. THE PASSAGE OF ANOTHER COLD FRONT MONDAY NIGHT WILL BRING A BRIEF INCREASE IN WINDS AND SEAS BACK TO NEAR ADVISORY LEVELS FOR LATE MONDAY NIGHT AND DURING THE DAY ON TUESDAY. WINDS AND SEAS WILL THEN AGAIN SETTLE BACK DOWN BELOW HEADLINE CRITERIA TUESDAY NIGHT INTO WEDNESDAY AS STRONG HIGH PRESSURE BUILDS DOWN FROM THE NORTH OVER THE FORECAST WATERS. && .FIRE WEATHER... WE WILL CONTINUE THE RED FLAG WARNING FOR THIS AFTERNOON AND THE FIRE WEATHER WATCH FOR MONDAY AFTERNOON. IT STILL LOOKS LIKE RED FLAG CONDITIONS WILL BE POSSIBLE TUESDAY AND WEDNESDAY AFTERNOONS AS WELL...ESPECIALLY IN OUR FL ZONES. && .PRELIMINARY POINT TEMPS/POPS... TALLAHASSEE 60 32 65 40 62 / 0 0 0 0 0 PANAMA CITY 60 39 65 43 64 / 0 0 0 0 0 DOTHAN 59 35 65 38 59 / 0 0 0 0 0 ALBANY 59 34 65 37 59 / 0 0 0 0 0 VALDOSTA 60 33 65 38 59 / 0 0 0 0 0 CROSS CITY 63 32 68 38 64 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...RED FLAG WARNING FROM NOON EST /11 AM CST/ TODAY TO 6 PM EST /5 PM CST/ THIS AFTERNOON FOR ALL OF THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND. FIRE WEATHER WATCH MONDAY AFTERNOON FOR ALL OF THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND. GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR THE THE NEAR SHORE MARINE ZONES FROM DESTIN FLORIDA EASTWARD TO THE MOUTH OF THE SUWANNEE RIVER OUT TO 20 NM. SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR THE OFFSHORE MARINE ZONES FROM DESTIN FLORIDA EASTWARD TO THE MOUTH OF THE SUWANNEE RIVER EXTENDING FROM 20 TO 60 NM OFFSHORE. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA LONG TERM/AVIATION/FIRE WX...FOURNIER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 952 PM EST MON NOV 17 2008 ...HARD FREEZE LIKELY AWAY FROM THE IMMEDIATE COAST TUESDAY NIGHT... .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT FOLLOWED BY COLD HIGH PRESSURE THAT WILL PERSIST THROUGH WEDNESDAY NIGHT. A DRY REINFORCING COLD FRONT WILL MOVE THROUGH THE AREA THURSDAY... FOLLOWED BY HIGH PRESSURE THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE STRONG COLD FRONT IS BEGINNING TO MOVE INTO THE WESTERN ZONES AND WILL SWEEP THROUGH THE ENTIRE FORECAST AREA OVER THE 2 HOURS OR SO BEFORE PUSHING OFFSHORE. EXPECT WINDS TO INCREASE AND DEWPOINTS TO FALL AFTER FRONTAL PASSAGE WITH TEMPERATURES INITIATING A STEADY DECLINE WITH THE ONSET OF STRONG COLD AIR ADVECTION. OVERNIGHT LOWS LOOK ON TRACK ALTHOUGH WILL NEED TO LOWER THEM 1-2 DEGS AROUND THE METTER...REIDSVILLE AND LUDOWICI AREAS BASED ON OBSERVATIONAL AND MODEL TRENDS. LOCATIONS WELL INLAND WILL DROP INTO THE LOWER TO MID 30S PRIOR TO SUNRISE...BUT LOCAL FROST TOOLS INDICATE NO CHANCES FOR FROST GIVEN THE DRYING SURFACE LAYER AND INCREASING WIND FIELDS. IN ALL VERY FEW CHANGES ARE NEEDED THIS EVENING. LAKE WINDS...WINDS ARE BEGINNING TO INCREASE ON LAKE MOULTRIE THIS EVENING AS THE COLD FRONT APPROACHES. WINDS WILL SURGE HARD BY MIDNIGHT THE ONSET OF STRONG COLD AIR ADVECTION. 850MB TEMPERATURES AROUND -5C COUPLED WITH LAKE TEMPERATURES IN THE LOWER 60S WILL YIELD VERY FAVORABLE MIXING PROFILES...WHICH SHOULD HELP SURGE WINDS SOLIDLY INTO THE 20-25 KT RANGE. THE LAKE WIND ADVISORY WILL CONTINUE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... DESPITE SUNNY SKIES...STRONG COLD ADVECTION...FEATURING A DEEPENING THERMAL TROUGH WITH 850 MB TEMPERATURES FALLING INTO THE -5C TO -9C RANGE...TEMPERATURES WILL STRUGGLE TO CLIMB OUT OF THE 40S AT MANY LOCATIONS TUESDAY. RECORD LOW MAXIMUM HIGH TEMPERATURES FOR NOVEMBER 18 WILL BE CHALLENGED...ESPECIALLY AT THE CHARLESTON AIRPORT. TUESDAY NIGHT...CONDITIONS APPEAR FAVORABLE FOR SEVERAL HOURS OF WIDESPREAD FREEZING TEMPERATURES...AND PERSISTENT OFFSHORE WINDS MAY PUSH FREEZING CONDITIONS TO THE COAST. THUS...ISSUED A FREEZE WATCH FOR ALL AREAS...EXCEPTING ALLENDALE...SCREVEN AND JENKINS COUNTIES WHERE THE GROWING SEASON HAS ENDED DUE TO AN EARLIER FREEZING EVENT. EXPECT LOWS TO RANGE FROM THE LOWER TO MID 20S ACROSS MANY AREAS AWAY FROM THE IMMEDIATE COAST...TO THE LOWER 30S ALONG THE COAST. RECORD LOW TEMPERATURES FOR NOVEMBER 19 WILL BE CHALLENGED. DESPITE THE VERY COLD TEMPERATURES...PERSISTENT N/NW WINDS SHOULD GREATLY LIMIT/PREVENT FROST FORMATION. LAKE WIND...OVER-LAKE INSTABILITY WILL CONTRIBUTE TO GUSTY WINDS...AS HIGH AS 30 KNOTS AT TIMES...OVER LAKE MOULTRIE TUESDAY AND TUESDAY NIGHT. PER 12Z MODEL TRENDS DEPICTING A SIGNIFICANT RELAXATION OF LOW LEVEL WINDS BY WEDNESDAY MORNING...ADJUSTED THE END TIME FOR THE LAKE WIND ADVISORY FROM NOON TO 6 AM WEDNESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... MOSTLY CLEAR AND COOL CONDITIONS WILL PREVAIL WED THROUGH SAT... DESPITE THE PASSAGE OF A DRY COLD FRONT ON THU. HIGH PRES WILL GRADUALLY SHIFT OFFSHORE WED NIGHT...BRINGING AN END TO THE STRONG CAA THAT WILL HAVE BROUGHT MAX TEMPS TO ONLY THE LOW-MID 50S WED FOLLOWED BY MIN TEMPS IN THE UPPER 20S TO LOWER 30S WED NIGHT. SOME MODEST WARM AIR ADVECTION WILL OCCUR THU AHEAD OF A COLD FROPA DUE FOR LATE DAY THU TO POSSIBLY THU EVE. ALTHOUGH THERE WILL BE SOME INCREASE IN CLOUD COVER...MAX TEMPS WILL REACH THE LOW-MID 60S WHICH IS STILL SOME 3-6 DEGREES BELOW NORMAL. DESPITE THE MODEST INCREASE IN THE MOISTURE COLUMN...NO PRECIP IS EXPECTED. ANOTHER SHOT OF CAA IS EXPECTED THU NIGHT THROUGH FRI NIGHT BEHIND THE CDFNT WITH AN E COAST TROUGH AND WESTERN RIDGE DEVELOPING...ALLOWING ANOTHER CANADIAN HIGH PRES AIRMASS TO SLIDE INTO THE ERN CONUS. MIN TEMPS WILL AGAIN DROP TO THE 30S WITH MAX TEMPS IN THE UPPER 50S TO LOWER 60S...BUT THE CAVEAT IS THAT THESE TEMPS COULD BE ON THE HIGH SIDE IF CAA IS STRONGER THAN ANTICIPATED. TEMPS MODERATE OVER THE WEEKEND CLOSER TO NORMAL LEVELS...BUT THE POSSIBILITY IS THERE THAT ANOTHER COLD FRONT MAY PUSH THROUGH ON MONDAY AND GIVE ANOTHER SHOT OF COLDER AIR. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AT BOTH SITES. HIGH PRESSURE WILL BEGIN BUILDING IN CAUSING A TIGHTENING OF THE PRESSURE GRADIENT AND INCREASING WINDS OVERNIGHT. SOUTHWESTERLY WINDS WILL EVENTUALLY VEER TOWARD THE WEST AND NORTHWEST THROUGH THE FORECAST PERIOD. EXPECT SUSTAINED WINDS NEAR 10 KNOTS WITH WINDS GUSTING AROUND 15 KNOTS AT BOTH AIRPORTS OVERNIGHT AND INCREASING TO 20 TO 25 KNOTS AFTER SUNRISE. EXTENDED AVIATION OUTLOOK...VFR. && .MARINE... WINDS WILL SURGE ACROSS THE WATERS TONIGHT IN THE WAKE OF STRONG COLD FRONT AND SMALL CRAFT ADVISORIES FOR THE NEARSHORE WATERS INCLUDING CHARLESTON HARBOR LOOK GOOD. SUSPECT THERE MAY BE 4-5 HOUR PERIOD OF GALES ACROSS THE GEORGIA OFFSHORE WATERS WHERE HIGH RESOLUTION SST DATA SHOWS WATER TEMPERATURES HOLDING IN THE UPPER 60S TO LOWER 70S BETWEEN 40 AND 60 NM OUT. RUC AND NAM ADJUSTED SOUNDINGS IN THIS AREA SUPPORT VIGOROUS MIXING PROFILES OVERNIGHT AS INTENSE COLD AIR ADVECTION INTERACTS WITH THESE WARMER WATERS. WILL ISSUE A GALE WARNING FOR THIS AREA THROUGH 5 AM...AFTER WHICH WINDS SHOULD SUBSIDE JUST BELOW GALE FORCE. A TIGHT SURFACE PRESSURE GRADIENT AND STRONG COLD ADVECTION/OVER WATER INSTABILITY WILL CONTRIBUTE TO A CONTINUATION OF WIDESPREAD SMALL CRAFT ADVISORY CONDITIONS TUESDAY AND TUESDAY NIGHT. AS CAA SHUTS DOWN BY WED MORNING...WIND SPEEDS WILL STEADILY DROP BELOW SCA LEVELS FOR ALL MARINE ZONES BY DAYBREAK WED. THE ONLY CONCERN IS SEAS...AND ATTM WAVE HEIGHTS ARE EXPECTED TO BE UNDER 6 FT FOR ALL NEARSHORE WATERS. HOWEVER...THE OUTER GA WATERS WILL BE SLOWER TO EXPERIENCE THE DROP UNDER THE SOLID OFFSHORE FLOW SO WILL MAINTAIN THE SCA HEADLINE THROUGH THE DAY ON WED. AS HIGH PRES MOVES ACRS THE WATERS WED INTO WED NIGHT...SEAS IN THE OUTER GA WATERS WILL DROP BELOW 6 FT. ANOTHER COLD FRONT IS EXPECTED FOR LATE THU INTO THU NIGHT AND ANOTHER SHOT OF CAA ALONG WITH IT THAT WILL INCREASE CONDITIONS OVER THE WATERS. ATTM...THE STRENGTH OF THE CAA DOES NOT APPEAR TO BE REACH THAT OF THE CAA EXPECTED FOR TUE SO HAVE KEPT SEAS NO HIGHER THAN 5 FT AND WIND SPEEDS NO HIGHER THAN 20 KT. SHOULD THE MODELS AND TRENDS DICTATE OTHERWISE...THEN SCA HEADLINES MAY BE NEEDED LATER THIS WEEK. HIGH PRES THEN RETURNS FOR FRI THROUGH THE WEEKEND...MAKING FOR TRANQUIL CONDS BY THEN. && .FIRE WEATHER... FIRE WEATHER CONCERNS ARISE BOTH TUE AND WED WITH THE DRY AIRMASS SETTLING OVER THE AREA ALONG WITH THE COLD AIR ADVECTION. FOR TUE...RH VALUES DROP TO AROUND THE CRITICAL LEVEL OF 25 PERCENT...RANGING FROM 24-27 PERCENT AWAY FROM THE COAST AND IN THE UPPER 20S CLOSER TO THE COAST. ADDED TO THAT WILL BE WIND SPEEDS NEAR TO AROUND CRITICAL LEVELS TUE AFTERNOON. HOWEVER...AFTER CONSULTING USERS IN BOTH SC AND GA...FUEL MOISTURES AT BOTH THE 10 AND 100 HOUR TIME RANGES ARE RUNNING MOIST ENOUGH FROM THE WEEKEND RAINS THAT NO ADDITIONAL FIRE WX STATEMENTS ARE NEEDED. FOR WED... WIND SPEEDS WILL BE LOWER BUT RH LEVELS WILL BE DRIER...POSSIBLY DROPPING BELOW 20 PERCENT. SINCE ONLY THE RH CRITERIA WILL BE REACHED ON WED...NO ADDITIONAL FIRE WX PRODUCTS WILL BE NEEDED. FOR BOTH TUE AND WED...WILL RUN WITH THE APPROPRIATE HEADLINES IN THE FIRE WEATHER PLANNING FORECAST. && .CLIMATE... RECORD LOW MAXIMUM TEMPERATURES FOR TUESDAY... CHS...49/1951 CHL...48/1951 SAV...45/1891 RECORD LOWS FOR WEDNESDAY... CHS...27/1949 CHL...32/1951 SAV...27/1951 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR GAZ099>101-114>119-137>141. SC...FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR SCZ042>045-047>051. LAKE WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR SCZ045. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR AMZ330-350- 352-354. GALE WARNING UNTIL 5 AM EST TUESDAY FOR AMZ374. && $$ ST ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 601 AM CST SUN NOV 16 2008 .DISCUSSION... 348 AM CST A COLD AIR MASS WILL REMAIN OVER THE REGION OF NORTH CENTRAL ILLINOIS... NORTHEAST ILLINOIS AND NORTHWEST INDIANA TODAY. THERE IS A CHANCE OF SOME SIGNIFICANT SNOW FOR NORTHWEST INDIANA MONDAY THROUGH TUESDAY. TODAY...THE WIND WILL BE FROM THE NORTHWEST AT 500 MB THROUGH TODAY AND TONIGHT. A VORTICITY MAXIMUM WILL MOVE THROUGH NORTHERN ILLINOIS AND NORTHWEST INDIANA TODAY. WE WILL FORECAST SCATTERED SNOW FLURRIES. THE SATELLITE IR LOOP SHOWS CLOUDS ASSOCIATED WITH THIS VORTICITY MAXIMUM MOVING INTO WISCONSIN THIS MORNING. THE LARGE AMPLITUDE TROUGH OVER THE GREAT LAKES WILL BE ALMOST STATIONARY TODAY. A WEAK SURFACE LOW WILL MOVE FROM NORTH DAKOTA TO MICHIGAN. THE LOW WILL CONTINUE TO WEAKEN BECOMING A TROUGH BY THIS EVENING. MONDAY THROUGH WEDNESDAY...THE LARGE AMPLITUDE TROUGH WILL MOVE EAST TO THE NORTHEAST UNITED STATES AND EASTERN QUEBEC BY EARLY WEDNESDAY MORNING. A SHORT WAVE TROUGH EMBEDDED IN THE LONG WAVE WILL MOVE ACROSS NORTHERN INDIANA MONDAY. WE WILL FORECAST SNOW FOR NORTHWEST INDIANA AND SCATTERED SNOW FLURRIES FOR NORTHERN ILLINOIS FOR MONDAY. THERE MAY BE SOME SIGNIFICANT SNOW IN NORTHWEST INDIANA. THE NEXT CHANCE OF SNOW WILL BE FRIDAY AND SATURDAY. THE REGION WILL STILL BE IN A NORTHWEST FLOW. SOME VERY COLD AIR MAY MOVE INTO THE REGION THURSDAY. ANOTHER SHORT WAVE TROUGH WILL MOVE INTO NORTHERN ILLINOIS WEDNESDAY NIGHT. && .AVIATION... 555 AM CST 12Z TAFORS...JUST AS THE STRATOCUMULUS DECK IS CLEARING OUT OF FAR NORTHEAST ILLINOIS AND NORTHWEST INDIANA EARLY THIS MORNING A MID DECK IS RAPIDLY SPREADING SOUTHEASTWARD ACROSS THE AREA IN THE WARM ADVECTION PATTERN AHEAD OF THE SHORT WAVE TROUGH DROPPING SOUTHEAST OVER MINNESOTA. AN ASSOCIATED SURFACE LOW WAS IN FAR WEST CENTRAL MINNESOTA AT 11Z WITH A 3MB/3HR PRESSURE FALL CENTER WAS DROPPING SOUTHEAST OVER WESTERN IOWA. 06Z RUNS OF GFS AND NAM FILLING THE CIRCULATION WITH ONLY A NORTHEAST-SOUTHWEST TROUGH DEPICTED ACROSS SOUTHEAST WISCONSIN AND NORTHEAST IOWA AT 18Z AND LOOKS A BIT TOO QUICK. 09Z RUC MAINTAINS A CLOSED SURFACE LOW ON THE IOWA-WISCONSIN BORDER AT THAT TIME AND LOOKS TO BE A BETTER FORECAST...THOUGH IT TO OPENS IT TO JUST A TROUGH ACROSS NORTHEAST AND WEST CENTRAL ILLINOIS BY 21Z. RADAR RETURNS ALREADY DEPICTED ALL THE WAY INTO NORTHERN ILLINOIS BUT NOTHING HAS BEEN REACHING THE GROUND FROM THE INVADING MID CLOUDS. FURTHER UPSTREAM WHERE LOW LEVEL LIFT IS BEING MAXIMIZED IN SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN AHEAD OF THE SURFACE LOW SNOWFALL IS BEING REPORTED BUT WITH VISIBILITY UNRESTRICTED FOR THE MOST PART. THIS LIGHT SNOW IS EXPECTED TO CONTINUE TO SLIP SOUTHEAST AS THE SURFACE LOW DOES SO AND MOVE ACROSS NORTHEAST IOWA...SOUTHWEST WISCONSIN AND NORTHWEST ILLINOIS DURING THE MORNING. AS THE LOW WEAKENS ANY LIGHT SNOW/SNOW SHOWERS THAT ARE PASSING TO THE WEST AND SOUTHWEST OF THE LOCAL TERMINALS ARE EXPECTED TO DIMINISH. THERE MAY BE A FEW INCONSEQUENTIAL FLURRIES AS THE MID LEVEL TROUGH PASSES DURING THE AFTERNOON AND INTO TONIGHT AS REINFORCING COLD AIR IS USHERED IN PUT NOT WORTHY OF INCLUSION IN THE TAFORS. WINDS WILL BACK A BIT TO WEST-SOUTHWEST AS THE LOW/TROUGH APPROACHES...AND SPEEDS DROP OFF FOR A COUPLE HOURS EITHER SIDE OF THE TROUGH PASSAGE AS A PRETTY WEAK PRESSURE GRADIENT IS DEPICTED BY THE MODELS. WINDS VEER TO THE NORTHWEST AND START TO PICK UP AGAIN AFTER THE MID LEVEL TROUGH PASSES BY BUT EXPECT ANY GUSTS TO REMAIN BELOW 20 KTS. SATELLITE AND METARS INDICATE ONLY LOCALIZED MVFR CEILINGS WITH VFR CLOUD COVER PREVAILING UPSTREAM. DRYING AND SUBSIDENCE TONIGHT EXPECTED TO CAUSE CLOUDS TO BECOME PATCHY AS CURRENTLY SEEN OVER THE DAKOTAS INTO WESTERN MINNESOTA AND IOWA SO HAVE SO HAVE VFR CONDITIONS THROUGH THE VALID PERIOD OF THE TAFORS. TRS && .MARINE... 305 AM CST LOW PRESSURE OVER SOUTHERN QUEBEC DEEPENS AS IT MOVES NORTHEAST TO LABRADOR BY MONDAY MORNING...WHILE HIGH PRESSURE BUILDS FROM THE CANADIAN ROCKIES TO SOUTHERN SASKATCHEWAN...SOUTHERN MANITOBA AND THE NORTHERN PLAINS. WINDS WILL CONTINUE TO DIMINISH TODAY AS THE LOW MOVES FURTHER AWAY...WHILE ALSO BACKING AHEAD OF AN APPROACHING TROUGH/COLD FRONT ASSOCIATED WITH A SHORT WAVE CURRENTLY DROPPING SOUTHEAST OVER FAR NORTHERN MINNESOTA AND WESTERN LAKE SUPERIOR. THE SHORT WAVE REACHES THE CENTRAL GREAT LAKES BY THIS EVENING WITH THE TROUGH AND THE REINFORCEMENT OF COLD AIR MOVING SOUTH AND SOUTHEAST ACROSS LAKE MICHIGAN FROM LATE MORNING THROUGH EARLY EVENING...VEERING WINDS TO NORTHWEST. ANOTHER SHORT WAVE AND ACCOMPANYING SHOT OF COLD AIR ARRIVES DURING MONDAY...WITH WINDS VEERING TO THE NORTH. WINDS DIMINISH TUESDAY AS THE CENTER OF A LARGE AREA OF HIGH PRESSURE MOVES SOUTHEAST ACROSS THE MID MISSISSIPPI VALLEY TO THE LOWER OHIO VALLEY. THE REINFORCEMENTS OF THE COLD AIR WILL KEEP LAKE EFFECT SHOW SHOWERS AND LOCAL SNOW SQUALLS GOING FROM TODAY TO WELL INTO TUESDAY. ACROSS NORTHERN LAKE MICHIGAN...LAKE EFFECT WILL STRETCH FROM LAKE SUPERIOR ACROSS THE UPPER PENINSULA AND ADDITIONAL ACTIVITY WILL BE OCCUR OVER LAKE MICHIGAN...WHILE SOUTHERN LAKE MICHIGAN WILL SEE THE ACTIVITY CONFINED TO MAINLY DOWNWIND LOCATIONS. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1024 PM EST MON NOV 17 2008 .UPDATE... MULTIPLE LES BANDS CONTINUE ACROSS PORTIONS OF THE AREA. THE HEAVIEST HAVE BEEN FROM THE BENTON HARBOR AREA SOUTHEAST THROUGH GOSHEN AND NOW HERE AT THE OFFICE. ANOTHER BAND SET UP FROM LAPORTE COUNTY SOUTHEAST. REPORTS OF SNOWFALL RATES OF AN INCH OR MORE PER HOUR ARE BECOMING COMMON.A FEW SNOW SHOWERS HAVE ALSO MADE IT AS FAR SOUTH AT THE FT WAYNE AREA. THESE BANDS WILL CONTINUE FOR THE NEXT COUPLE HOURS AS THE S/W EXITS THE AREA. WHAT IS OF GREATER CONCERN IS AS WAS FORECAST HERE AND BY 18Z NAM...MESO LOW HAS SETUP AND IS WORKING SOUTH ALONG THE EASTERN PART OF THE LAKE. ECHO TOPS ON SOME OF THE CELLS WERE EXCEEDING 15,000 FEET. IN GENERAL...ESPECIALLY IN THE FAR NW PART OF THE AREA...THE FORECAST IS IN GREAT SHAPE FOR NOW. THE AREA OF CONCERN INTO THE OVERNIGHT HOURS IS ACROSS CASS COUNTY MI...ELKHART COUNTY INDIANA AND MAYBE INTO PORTIONS OF KOSICUSKO COUNTY. HEADLINES ARE SET TO EXPIRE AT 1 AM FOR CASS AND ELKHART COUNTIES. THESE 2 COUNTIES HAVE SEEN LIKELY AN ADDITIONAL 1 TO 3 INCHES OF SNOW JUST THIS EVENING IN SPOTS WITH THE SNOW BANDS. WITH THE SOUTHERN END OF THE MESOVORT LOOKING TO PASS OVER AT LEAST WESTERN CASS COUNTY AND POSSIBLY INTO ELKHART COUNTY...THEY WILL LIKELY SEE A CONTINUATION OF THE PERIODS OF MODERATE TO HEAVY SNOW. TIMING OUT THE BACK EDGE OF THE CURL PLACES IT THROUGH CASS COUNTY MI BY 1 AM AND ELKHART BETWEEN 1 AND 2 AM. WILL GO AHEAD AND LET THINGS RIDE FOR NOW AND LET OVERNIGHT SHIFT MONITOR TRENDS. && .PREV DISCUSSION... /ISSUED 650 PM EST MON NOV 17 2008/ AVIATION... COMPLICATED TAFS IN STORE AT KSBN AS BANDS OF LAKE EFFECT SNOWSHOWERS WILL INCREASE OVER THE NEXT COUPLE HOURS WITH ONE DOMINANT BAND STILL SET TO MOVE ACROSS THE AREA. HAVE CONTINUED WITH OVERALL IDEA OF 18Z TAFS WITH MINOR CHANGES IN THE 1ST 6 HOURS TO ADDRESS WHAT IS BEING OBSERVED UPSTREAM AND BEING HINTED AT BY BOTH NAM12 AND 00Z/17 4KM WRF. AS THE BAND BECOME BETTER DEVELOPED IN THE NEXT COUPLE OF HOURS...AMENDMENTS WILL BE LIKELY BUT FOR NOW LIFR CONDITIONS BEING CONFINED TO TEMPO GROUP. BY THE 12 TO 15Z TIME FRAME THE BULK OF THE SNOWS SHOULD BE WEST OF KSBN. AT KFWA...EFFECTS OF LES WILL BE MUCH LESS SIGNIFICANT. HOWEVER...MODELS STILL SUGGEST AS THE MAIN BAND IS DEVELOPING THAT A LONG FETCH EXTENT COULD OCCUR WITH THE BAND CLEAR INTO PORTIONS OF CNTRL OHIO. WILL ADD A TEMPO GROUP FOR 5SM AND MVFR CIGS LATER THIS EVENING TO ACCOUNT FOR THIS. PREV DISCUSSION... /ISSUED 512 PM EST MON NOV 17 2008/ SHORT TERM... .HEAVY LAKE EFFECT SNOW TONIGHT INTO TUESDAY... CURRENT WATER IMAGERY DISPLAYS A VERY POTENT SHORT WAVE TROUGH DIVING INTO THE GREAT LAKES REGION....WHICH WILL SUPPORT ANOTHER BLAST OF CAA INTO THE REGION AND MORE IMPORTANTLY LEND TO THE DEVELOPMENT OF HEAVY LAKE EFFECT SNOWS ACROSS PORTIONS OF SW MI AND NORTHERN IN. SHORT TERM MODEL SOLUTIONS VARY SOME ON THE FINE DETAILS OF HOW THE LAKE EFFECT PROCESS WILL PLAY OUT...ALTHOUGH ONE THING HAS BEEN PERSISTENT IN THE LAST SEVERAL RUNS OF THE GEFS/NAEFS ENSEMBLES AS WELL AS THE ECMWF/GEM/AND NAM...THAT BEING LONG FETCH AGGREGATE NORTHERLY FLOW OVER LAKE MI WITH EXTREME DELTA T/S OF NEARLY 20 C OR HIGHER...RESULTING IN EXTREME LL UPWARD DIRECTED OMEGA OVER BERRIEN/LA PORTE AND WESTERN SAINT JOSEPH /IN/ COUNTIES TONIGHT. HAVE UTILIZED MANY SHORT TERM MODELS IN THE PERIOD...SPECIFICALLY THE WRF/NMM/GFS/RUC 13 AND ECMWF TO TRY AND RESOLVE TIMING OF CONVECTIVE BANDS/AFFECTED AREAS/AND SNOW TOTALS BASED ON QPF TRENDS. NUMEROUS PARALLEL BANDS ARE ONGOING ACROSS PORTIONS OF SW MI AND EXTREME NORTHERN IN. EVOLUTION OF THESE LAKE EFFECT BANDS INTO A MID LAKE BAND IS EXPECTED GIVEN THE EXTREME DELTA T/S/ROBUST LAKE INDUCED CAPES OF NEARLY 1000 J/KG AS INDICATED IN BUFFER SOUNDINGS/ AND VEERING FLOW TO MORE N/NW AND EVENTUALLY N BY TUES MORNING. EXTREME INSTABILITY WILL ALSO SUPPORT THE POTENTIAL FOR MESO-LOW DEVELOPMENT WHICH WILL WILL HAVE PROFOUND IMPACTS ON THE OVERALL ORGANIZATION OF THE LAKE EFFECT EVENT...ALLOWING SOME UNCERTAINTY IN THE LOCATION OF THE HEAVIEST SNOWFALL. CURRENT INDICATIONS PROG WESTERN BERRIEN/MUCH OF LA PORTE/AND FAR WESTERN SAINT JOSEPH COUNTIES AS THE PRIME LOCATION FOR THE HEAVIEST AND MOST INTENSE SNOWFALL. PARALLEL BANDS WILL BEGIN TO REV UP IN INTENSITY LATE THIS AFTERNOON/EVENING IN RESPONSE TO THE ADVANCING UPPER IMPULSE. THE INTENSE NATURE OF THIS FEATURE...WHICH SUPPORTS H5 TEMPS DOWN TO -38C WILL SUPPORT INCREASING INVERSION HEIGHTS TO 17 KFT AND STAGGERING LAKE INDUCED CAPES OF 800-1000 J/KG...ADDITIONALLY SUPPORTED BY LAKE AGGREGATE AFFECTS FROM LAKE SUPERIOR. EL OF NEARLY 20KFT WILL SUPPORT LIGHTNING POTENTIAL IN ADDITION TO SLEET. HAVE WORDED THIS IN THE FORECAST. LONG PERIOD OF PARALLEL BAND SETUP THIS EVENING WILL SUPPORT DECENT ACCUMS OF 3 TO 5 INCHES ACROSS SW MI AND EXTREME NORTHERN IN...WITH LOCALLY HEAVIER AMOUNTS. GROWING INSTABILITY WILL THEN ALLOW MORE INTENSE BANDING TO DEVELOP LATER THIS EVENING WHILE SHIFTING WEST INTO WESTERN BERRIEN/ LA PORTE/WESTERN ST. JOE/AND STARKE COUNTIES. GIVEN THE EXTREME CONVECTIVE SETUP...EXPECTING ANYWHERE FROM 6 TO 15 INCHES IN AREAS WHERE THE DURATION/INTENSITY ARE MAXIMIZED...WHICH LOOKS TO BE IN EXTREME SW BERRIEN AND LA PORTE COUNTIES WHERE SNOWFALL RATES OF 2 TO 5 INCHES PER HOUR ARE EXPECTED...WITH VISIBILITY NEAR ZERO AT TIMES. BLOWING AND DRIFTING OF SNOW WILL BE POSSIBLE AS LL FLOW RESPONDS TO MESOSCALE PROCESSES. THIS INCLUDES PORTIONS OF INTERSTATE 80/90 AND 94. THERE IS SOME QUESTION AS TO HOW LONG THIS PERIOD OF INTENSE SNOWFALL WILL BE...AS MESOLOW DEVELOPMENT WILL ALLOW DISRUPTION IN THE FLOW SHIFTING THE BAND EAST AND WEST. HAVE ISSUED A WARNING FOR THE HEAVY SNOWFALL TOTALS AS AT LEAST 6 INCHES WILL BE EXPECTED IN PORTIONS OF THE WARNED COUNTIES. THINGS WILL BEGIN TO DIMINISH SOME BY TUES AFTERNOON WITH INVERSION HEIGHTS RAISING IN REPONSE TO UPPER LEVEL RIDGING. EXPECTING THE MID LAND BAND TO BREAK DOWN AND SHIFT BACK EAST...TRANSITIONING INTO A MULTIPLE PARALLEL BANDS...WITH SOME INTENSE SNOWFALL RATES POSSIBLE BEFORE WINDING DOWN TUES EVENING. AS FOR TEMPS...EXPECT BELOW NORMAL TEMPS WITH HIGHS IN THE 30S AGAIN TUES AND LOWS IN THE 20S. LONG TERM... .TUESDAY NIGHT THROUGH MONDAY... ACTIVE WEATHER PATTERN TO CONTINUE WITH NUMEROUS SHORT WAVES...MORE LAKE EFFECT POTENTIAL AND POSSIBLE STRONG STORM SYSTEM DAY 6 AND DAY 7. RELIANCE REMAINS IN THE ECMWF IN LONG TERM WITH HEAVIER WEIGHT ON NAM WRF IN 36 TO 84 HOUR RANGE. SURFACE HIGH WILL SLIDE ACROSS THE AREA TUESDAY NIGHT WITH WARM AIR ADVECTION BEGINNING OVERNIGHT IN EARNEST. CONCERN IS THAT LOW LEVEL WINDS WILL DECOUPLE EARLY WITH HIGH OVERHEAD WHICH WILL LEAD TO STRONG RADIATIONAL COOLING OVER FRESH AND DEEP SNOWPACK IN NORTHWEST. CURRENT INDICATIONS ARE THAT A MID LEVEL CLOUD DECK COULD DEVELOP WITH WAA LATER IN THE EVENING AND DROP WILL SLOW AND POSSIBLY RISE LATE. HAVE ADJUSTED GRIDS DOWN BELOW GUIDANCE AND INTO THE TEENS AT THIS TIME BUT WILL BE QUITE TRICKY AS POTENTIAL FOR A VERY COLD EVENING IS THERE IF WE REMAIN DECOUPLED AND CLEAR FOR SEVERAL HOURS. SOUTHWEST FLOW AND WARM AIR ADVECTION OCCUR WED INTO WED NIGHT AHEAD OF NEXT POTENT CLIPPER AND MORE POLAR AIR. SHOULD GET TO NEAR NORMAL ON WED BUT TEMPS WILL BE TEMPERED OVER SNOWPACK. COLDER AIR ARRIVES IN EARNEST THURSDAY BASED ON LATEST MODEL RUNS WITH NORTHWEST FLOW SETTING UP. MODELS AGAIN LOOK TOO LOW WITH MOISTURE FIELDS BUT GIVEN DELTA T VALUES NEAR 20 AND NORTHWEST FLOW EXPECT SNOW SHOWERS TO BE A STRONG POSSIBILITY WITH ACCUMULATIONS POSSIBLE AGAIN. HAVE TRENDED POPS UP INTO LIKELY CATEGORY BUT ACCUMS AND LOCATION REMAIN UNCERTAIN. COLDER AIR HANGS AROUND INTO THE WEEKEND BUT ECMWF REMAINS CONSISTENT WITH POTENT STORM SYSTEM DEVELOPING AND MOVING THROUGH OHIO VALLEY REGION. EXPECT THIS TRACK TO SHIFT NORTH WITH TIME AS MEDIUM RANGE MODELS TEND TO BE TOO FAR SOUTH WITH EARLY SEASON STORM TRACKS. OUR AREA CURRENTLY LOOKS TO BE ON FRINGE OF MIXED PRECIPITATION LINE WITH LOW MOVING ACROSS CWA SUNDAY INTO MONDAY. WILL HAVE RAIN SOUTH AND A RAIN OR SNOW MENTION NORTH...TRANSITIONING TO ALL SNOW ON MONDAY. DETAILS WILL CERTAINLY CHANGE SO HAVE KEPT DETAILS TO A MINIMUM AND TRYING TO HIT BIG PICTURE. GFS HAS BEEN INCONSISTENT AND GENERALLY SIDED TOWARD HPC AND CURRENT GRIDS FOR THESE LATER PERIODS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW WARNING UNTIL 12 PM CST TUESDAY FOR INZ003-012. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST TUESDAY FOR INZ013. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR INZ005. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR INZ004. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR INZ014-015. MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST TUESDAY FOR MIZ077. LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUESDAY FOR MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...LASHLEY AVIATION/UPDATE...FISHER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 650 PM EST MON NOV 17 2008 .AVIATION... COMPLICATED TAFS IN STORE AT KSBN AS BANDS OF LAKE EFFECT SNOWSHOWERS WILL INCREASE OVER THE NEXT COUPLE HOURS WITH ONE DOMINANT BAND STILL SET TO MOVE ACROSS THE AREA. HAVE CONTINUED WITH OVERALL IDEA OF 18Z TAFS WITH MINOR CHANGES IN THE 1ST 6 HOURS TO ADDRESS WHAT IS BEING OBSERVED UPSTREAM AND BEING HINTED AT BY BOTH NAM12 AND 00Z/17 4KM WRF. AS THE BAND BECOME BETTER DEVELOPED IN THE NEXT COUPLE OF HOURS...AMENDMENTS WILL BE LIKELY BUT FOR NOW LIFR CONDITIONS BEING CONFINED TO TEMPO GROUP. BY THE 12 TO 15Z TIME FRAME THE BULK OF THE SNOWS SHOULD BE WEST OF KSBN. AT KFWA...EFFECTS OF LES WILL BE MUCH LESS SIGNIFICANT. HOWEVER...MODELS STILL SUGGEST AS THE MAIN BAND IS DEVELOPING THAT A LONG FETCH EXTENT COULD OCCUR WITH THE BAND CLEAR INTO PORTIONS OF CNTRL OHIO. WILL ADD A TEMPO GROUP FOR 5SM AND MVFR CIGS LATER THIS EVENING TO ACCOUNT FOR THIS. && .PREV DISCUSSION... /ISSUED 512 PM EST MON NOV 17 2008/ SHORT TERM... ..HEAVY LAKE EFFECT SNOW TONIGHT INTO TUESDAY... CURRENT WATER IMAGERY DISPLAYS A VERY POTENT SHORT WAVE TROUGH DIVING INTO THE GREAT LAKES REGION....WHICH WILL SUPPORT ANOTHER BLAST OF CAA INTO THE REGION AND MORE IMPORTANTLY LEND TO THE DEVELOPMENT OF HEAVY LAKE EFFECT SNOWS ACROSS PORTIONS OF SW MI AND NORTHERN IN. SHORT TERM MODEL SOLUTIONS VARY SOME ON THE FINE DETAILS OF HOW THE LAKE EFFECT PROCESS WILL PLAY OUT...ALTHOUGH ONE THING HAS BEEN PERSISTENT IN THE LAST SEVERAL RUNS OF THE GEFS/NAEFS ENSEMBLES AS WELL AS THE ECMWF/GEM/AND NAM...THAT BEING LONG FETCH AGGREGATE NORTHERLY FLOW OVER LAKE MI WITH EXTREME DELTA T/S OF NEARLY 20 C OR HIGHER...RESULTING IN EXTREME LL UPWARD DIRECTED OMEGA OVER BERRIEN/LA PORTE AND WESTERN SAINT JOSEPH /IN/ COUNTIES TONIGHT. HAVE UTILIZED MANY SHORT TERM MODELS IN THE PERIOD...SPECIFICALLY THE WRF/NMM/GFS/RUC 13 AND ECMWF TO TRY AND RESOLVE TIMING OF CONVECTIVE BANDS/AFFECTED AREAS/AND SNOW TOTALS BASED ON QPF TRENDS. NUMEROUS PARALLEL BANDS ARE ONGOING ACROSS PORTIONS OF SW MI AND EXTREME NORTHERN IN. EVOLUTION OF THESE LAKE EFFECT BANDS INTO A MID LAKE BAND IS EXPECTED GIVEN THE EXTREME DELTA T/S/ROBUST LAKE INDUCED CAPES OF NEARLY 1000 J/KG AS INDICATED IN BUFFER SOUNDINGS/ AND VEERING FLOW TO MORE N/NW AND EVENTUALLY N BY TUES MORNING. EXTREME INSTABILITY WILL ALSO SUPPORT THE POTENTIAL FOR MESO-LOW DEVELOPMENT WHICH WILL WILL HAVE PROFOUND IMPACTS ON THE OVERALL ORGANIZATION OF THE LAKE EFFECT EVENT...ALLOWING SOME UNCERTAINTY IN THE LOCATION OF THE HEAVIEST SNOWFALL. CURRENT INDICATIONS PROG WESTERN BERRIEN/MUCH OF LA PORTE/AND FAR WESTERN SAINT JOSEPH COUNTIES AS THE PRIME LOCATION FOR THE HEAVIEST AND MOST INTENSE SNOWFALL. PARALLEL BANDS WILL BEGIN TO REV UP IN INTENSITY LATE THIS AFTERNOON/EVENING IN RESPONSE TO THE ADVANCING UPPER IMPULSE. THE INTENSE NATURE OF THIS FEATURE...WHICH SUPPORTS H5 TEMPS DOWN TO -38C WILL SUPPORT INCREASING INVERSION HEIGHTS TO 17 KFT AND STAGGERING LAKE INDUCED CAPES OF 800-1000 J/KG...ADDITIONALLY SUPPORTED BY LAKE AGGREGATE AFFECTS FROM LAKE SUPERIOR. EL OF NEARLY 20KFT WILL SUPPORT LIGHTNING POTENTIAL IN ADDITION TO SLEET. HAVE WORDED THIS IN THE FORECAST. LONG PERIOD OF PARALLEL BAND SETUP THIS EVENING WILL SUPPORT DECENT ACCUMS OF 3 TO 5 INCHES ACROSS SW MI AND EXTREME NORTHERN IN...WITH LOCALLY HEAVIER AMOUNTS. GROWING INSTABILITY WILL THEN ALLOW MORE INTENSE BANDING TO DEVELOP LATER THIS EVENING WHILE SHIFTING WEST INTO WESTERN BERRIEN/ LA PORTE/WESTERN ST. JOE/AND STARKE COUNTIES. GIVEN THE EXTREME CONVECTIVE SETUP...EXPECTING ANYWHERE FROM 6 TO 15 INCHES IN AREAS WHERE THE DURATION/INTENSITY ARE MAXIMIZED...WHICH LOOKS TO BE IN EXTREME SW BERRIEN AND LA PORTE COUNTIES WHERE SNOWFALL RATES OF 2 TO 5 INCHES PER HOUR ARE EXPECTED...WITH VISIBILITY NEAR ZERO AT TIMES. BLOWING AND DRIFTING OF SNOW WILL BE POSSIBLE AS LL FLOW RESPONDS TO MESOSCALE PROCESSES. THIS INCLUDES PORTIONS OF INTERSTATE 80/90 AND 94. THERE IS SOME QUESTION AS TO HOW LONG THIS PERIOD OF INTENSE SNOWFALL WILL BE...AS MESOLOW DEVELOPMENT WILL ALLOW DISRUPTION IN THE FLOW SHIFTING THE BAND EAST AND WEST. HAVE ISSUED A WARNING FOR THE HEAVY SNOWFALL TOTALS AS AT LEAST 6 INCHES WILL BE EXPECTED IN PORTIONS OF THE WARNED COUNTIES. THINGS WILL BEGIN TO DIMINISH SOME BY TUES AFTERNOON WITH INVERSION HEIGHTS RAISING IN REPONSE TO UPPER LEVEL RIDGING. EXPECTING THE MID LAND BAND TO BREAK DOWN AND SHIFT BACK EAST...TRANSITIONING INTO A MULTIPLE PARALLEL BANDS...WITH SOME INTENSE SNOWFALL RATES POSSIBLE BEFORE WINDING DOWN TUES EVENING. AS FOR TEMPS...EXPECT BELOW NORMAL TEMPS WITH HIGHS IN THE 30S AGAIN TUES AND LOWS IN THE 20S. LONG TERM... ..TUESDAY NIGHT THROUGH MONDAY... ACTIVE WEATHER PATTERN TO CONTINUE WITH NUMEROUS SHORT WAVES...MORE LAKE EFFECT POTENTIAL AND POSSIBLE STRONG STORM SYSTEM DAY 6 AND DAY 7. RELIANCE REMAINS IN THE ECMWF IN LONG TERM WITH HEAVIER WEIGHT ON NAM WRF IN 36 TO 84 HOUR RANGE. SURFACE HIGH WILL SLIDE ACROSS THE AREA TUESDAY NIGHT WITH WARM AIR ADVECTION BEGINNING OVERNIGHT IN EARNEST. CONCERN IS THAT LOW LEVEL WINDS WILL DECOUPLE EARLY WITH HIGH OVERHEAD WHICH WILL LEAD TO STRONG RADIATIONAL COOLING OVER FRESH AND DEEP SNOWPACK IN NORTHWEST. CURRENT INDICATIONS ARE THAT A MID LEVEL CLOUD DECK COULD DEVELOP WITH WAA LATER IN THE EVENING AND DROP WILL SLOW AND POSSIBLY RISE LATE. HAVE ADJUSTED GRIDS DOWN BELOW GUIDANCE AND INTO THE TEENS AT THIS TIME BUT WILL BE QUITE TRICKY AS POTENTIAL FOR A VERY COLD EVENING IS THERE IF WE REMAIN DECOUPLED AND CLEAR FOR SEVERAL HOURS. SOUTHWEST FLOW AND WARM AIR ADVECTION OCCUR WED INTO WED NIGHT AHEAD OF NEXT POTENT CLIPPER AND MORE POLAR AIR. SHOULD GET TO NEAR NORMAL ON WED BUT TEMPS WILL BE TEMPERED OVER SNOWPACK. COLDER AIR ARRIVES IN EARNEST THURSDAY BASED ON LATEST MODEL RUNS WITH NORTHWEST FLOW SETTING UP. MODELS AGAIN LOOK TOO LOW WITH MOISTURE FIELDS BUT GIVEN DELTA T VALUES NEAR 20 AND NORTHWEST FLOW EXPECT SNOW SHOWERS TO BE A STRONG POSSIBILITY WITH ACCUMULATIONS POSSIBLE AGAIN. HAVE TRENDED POPS UP INTO LIKELY CATEGORY BUT ACCUMS AND LOCATION REMAIN UNCERTAIN. COLDER AIR HANGS AROUND INTO THE WEEKEND BUT ECMWF REMAINS CONSISTENT WITH POTENT STORM SYSTEM DEVELOPING AND MOVING THROUGH OHIO VALLEY REGION. EXPECT THIS TRACK TO SHIFT NORTH WITH TIME AS MEDIUM RANGE MODELS TEND TO BE TOO FAR SOUTH WITH EARLY SEASON STORM TRACKS. OUR AREA CURRENTLY LOOKS TO BE ON FRINGE OF MIXED PRECIPITATION LINE WITH LOW MOVING ACROSS CWA SUNDAY INTO MONDAY. WILL HAVE RAIN SOUTH AND A RAIN OR SNOW MENTION NORTH...TRANSITIONING TO ALL SNOW ON MONDAY. DETAILS WILL CERTAINLY CHANGE SO HAVE KEPT DETAILS TO A MINIMUM AND TRYING TO HIT BIG PICTURE. GFS HAS BEEN INCONSISTENT AND GENERALLY SIDED TOWARD HPC AND CURRENT GRIDS FOR THESE LATER PERIODS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR INZ014-015. LAKE EFFECT SNOW WARNING UNTIL 12 PM CST TUESDAY FOR INZ003-012. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST TUESDAY FOR INZ013. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR INZ005. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR INZ004. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ006. MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST TUESDAY FOR MIZ077. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ079. LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUESDAY FOR MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...LASHLEY AVIATION...FISHER in AREA FORECAST DISCUSSION...DELAYED NATIONAL WEATHER SERVICE NORTHERN INDIANA 512 PM EST MON NOV 17 2008 .SHORT TERM... ...HEAVY LAKE EFFECT SNOW TONIGHT INTO TUESDAY... CURRENT WATER IMAGERY DISPLAYS A VERY POTENT SHORT WAVE TROUGH DIVING INTO THE GREAT LAKES REGION....WHICH WILL SUPPORT ANOTHER BLAST OF CAA INTO THE REGION AND MORE IMPORTANTLY LEND TO THE DEVELOPMENT OF HEAVY LAKE EFFECT SNOWS ACROSS PORTIONS OF SW MI AND NORTHERN IN. SHORT TERM MODEL SOLUTIONS VARY SOME ON THE FINE DETAILS OF HOW THE LAKE EFFECT PROCESS WILL PLAY OUT...ALTHOUGH ONE THING HAS BEEN PERSISTENT IN THE LAST SEVERAL RUNS OF THE GEFS/NAEFS ENSEMBLES AS WELL AS THE ECMWF/GEM/AND NAM...THAT BEING LONG FETCH AGGREGATE NORTHERLY FLOW OVER LAKE MI WITH EXTREME DELTA T/S OF NEARLY 20 C OR HIGHER...RESULTING IN EXTREME LL UPWARD DIRECTED OMEGA OVER BERRIEN/LA PORTE AND WESTERN SAINT JOSEPH /IN/ COUNTIES TONIGHT. HAVE UTILIZED MANY SHORT TERM MODELS IN THE PERIOD...SPECIFICALLY THE WRF/NMM/GFS/RUC 13 AND ECMWF TO TRY AND RESOLVE TIMING OF CONVECTIVE BANDS/AFFECTED AREAS/AND SNOW TOTALS BASED ON QPF TRENDS. NUMEROUS PARALLEL BANDS ARE ONGOING ACROSS PORTIONS OF SW MI AND EXTREME NORTHERN IN. EVOLUTION OF THESE LAKE EFFECT BANDS INTO A MID LAKE BAND IS EXPECTED GIVEN THE EXTREME DELTA T/S/ROBUST LAKE INDUCED CAPES OF NEARLY 1000 J/KG AS INDICATED IN BUFFER SOUNDINGS/ AND VEERING FLOW TO MORE N/NW AND EVENTUALLY N BY TUES MORNING. EXTREME INSTABILITY WILL ALSO SUPPORT THE POTENTIAL FOR MESO-LOW DEVELOPMENT WHICH WILL WILL HAVE PROFOUND IMPACTS ON THE OVERALL ORGANIZATION OF THE LAKE EFFECT EVENT...ALLOWING SOME UNCERTAINTY IN THE LOCATION OF THE HEAVIEST SNOWFALL. CURRENT INDICATIONS PROG WESTERN BERRIEN/MUCH OF LA PORTE/AND FAR WESTERN SAINT JOSEPH COUNTIES AS THE PRIME LOCATION FOR THE HEAVIEST AND MOST INTENSE SNOWFALL. PARALLEL BANDS WILL BEGIN TO REV UP IN INTENSITY LATE THIS AFTERNOON/EVENING IN RESPONSE TO THE ADVANCING UPPER IMPULSE. THE INTENSE NATURE OF THIS FEATURE...WHICH SUPPORTS H5 TEMPS DOWN TO -38C WILL SUPPORT INCREASING INVERSION HEIGHTS TO 17 KFT AND STAGGERING LAKE INDUCED CAPES OF 800-1000 J/KG...ADDITIONALLY SUPPORTED BY LAKE AGGREGATE AFFECTS FROM LAKE SUPERIOR. EL OF NEARLY 20KFT WILL SUPPORT LIGHTNING POTENTIAL IN ADDITION TO SLEET. HAVE WORDED THIS IN THE FORECAST. LONG PERIOD OF PARALLEL BAND SETUP THIS EVENING WILL SUPPORT DECENT ACCUMS OF 3 TO 5 INCHES ACROSS SW MI AND EXTREME NORTHERN IN...WITH LOCALLY HEAVIER AMOUNTS. GROWING INSTABILITY WILL THEN ALLOW MORE INTENSE BANDING TO DEVELOP LATER THIS EVENING WHILE SHIFTING WEST INTO WESTERN BERRIEN/ LA PORTE/WESTERN ST. JOE/AND STARKE COUNTIES. GIVEN THE EXTREME CONVECTIVE SETUP...EXPECTING ANYWHERE FROM 6 TO 15 INCHES IN AREAS WHERE THE DURATION/INTENSITY ARE MAXIMIZED...WHICH LOOKS TO BE IN EXTREME SW BERRIEN AND LA PORTE COUNTIES WHERE SNOWFALL RATES OF 2 TO 5 INCHES PER HOUR ARE EXPECTED...WITH VISIBILITY NEAR ZERO AT TIMES. BLOWING AND DRIFTING OF SNOW WILL BE POSSIBLE AS LL FLOW RESPONDS TO MESOSCALE PROCESSES. THIS INCLUDES PORTIONS OF INTERSTATE 80/90 AND 94. THERE IS SOME QUESTION AS TO HOW LONG THIS PERIOD OF INTENSE SNOWFALL WILL BE...AS MESOLOW DEVELOPMENT WILL ALLOW DISRUPTION IN THE FLOW SHIFTING THE BAND EAST AND WEST. HAVE ISSUED A WARNING FOR THE HEAVY SNOWFALL TOTALS AS AT LEAST 6 INCHES WILL BE EXPECTED IN PORTIONS OF THE WARNED COUNTIES. THINGS WILL BEGIN TO DIMINISH SOME BY TUES AFTERNOON WITH INVERSION HEIGHTS RAISING IN REPONSE TO UPPER LEVEL RIDGING. EXPECTING THE MID LAND BAND TO BREAK DOWN AND SHIFT BACK EAST...TRANSITIONING INTO A MULTIPLE PARALLEL BANDS...WITH SOME INTENSE SNOWFALL RATES POSSIBLE BEFORE WINDING DOWN TUES EVENING. AS FOR TEMPS...EXPECT BELOW NORMAL TEMPS WITH HIGHS IN THE 30S AGAIN TUES AND LOWS IN THE 20S. && .LONG TERM... ...TUESDAY NIGHT THROUGH MONDAY... ACTIVE WEATHER PATTERN TO CONTINUE WITH NUMEROUS SHORT WAVES...MORE LAKE EFFECT POTENTIAL AND POSSIBLE STRONG STORM SYSTEM DAY 6 AND DAY 7. RELIANCE REMAINS IN THE ECMWF IN LONG TERM WITH HEAVIER WEIGHT ON NAM WRF IN 36 TO 84 HOUR RANGE. SURFACE HIGH WILL SLIDE ACROSS THE AREA TUESDAY NIGHT WITH WARM AIR ADVECTION BEGINNING OVERNIGHT IN EARNEST. CONCERN IS THAT LOW LEVEL WINDS WILL DECOUPLE EARLY WITH HIGH OVERHEAD WHICH WILL LEAD TO STRONG RADIATIONAL COOLING OVER FRESH AND DEEP SNOWPACK IN NORTHWEST. CURRENT INDICATIONS ARE THAT A MID LEVEL CLOUD DECK COULD DEVELOP WITH WAA LATER IN THE EVENING AND DROP WILL SLOW AND POSSIBLY RISE LATE. HAVE ADJUSTED GRIDS DOWN BELOW GUIDANCE AND INTO THE TEENS AT THIS TIME BUT WILL BE QUITE TRICKY AS POTENTIAL FOR A VERY COLD EVENING IS THERE IF WE REMAIN DECOUPLED AND CLEAR FOR SEVERAL HOURS. SOUTHWEST FLOW AND WARM AIR ADVECTION OCCUR WED INTO WED NIGHT AHEAD OF NEXT POTENT CLIPPER AND MORE POLAR AIR. SHOULD GET TO NEAR NORMAL ON WED BUT TEMPS WILL BE TEMPERED OVER SNOWPACK. COLDER AIR ARRIVES IN EARNEST THURSDAY BASED ON LATEST MODEL RUNS WITH NORTHWEST FLOW SETTING UP. MODELS AGAIN LOOK TOO LOW WITH MOISTURE FIELDS BUT GIVEN DELTA T VALUES NEAR 20 AND NORTHWEST FLOW EXPECT SNOW SHOWERS TO BE A STRONG POSSIBILITY WITH ACCUMULATIONS POSSIBLE AGAIN. HAVE TRENDED POPS UP INTO LIKELY CATEGORY BUT ACCUMS AND LOCATION REMAIN UNCERTAIN. COLDER AIR HANGS AROUND INTO THE WEEKEND BUT ECMWF REMAINS CONSISTENT WITH POTENT STORM SYSTEM DEVELOPING AND MOVING THROUGH OHIO VALLEY REGION. EXPECT THIS TRACK TO SHIFT NORTH WITH TIME AS MEDIUM RANGE MODELS TEND TO BE TOO FAR SOUTH WITH EARLY SEASON STORM TRACKS. OUR AREA CURRENTLY LOOKS TO BE ON FRINGE OF MIXED PRECIPITATION LINE WITH LOW MOVING ACROSS CWA SUNDAY INTO MONDAY. WILL HAVE RAIN SOUTH AND A RAIN OR SNOW MENTION NORTH...TRANSITIONING TO ALL SNOW ON MONDAY. DETAILS WILL CERTAINLY CHANGE SO HAVE KEPT DETAILS TO A MINIMUM AND TRYING TO HIT BIG PICTURE. GFS HAS BEEN INCONSISTENT AND GENERALLY SIDED TOWARD HPC AND CURRENT GRIDS FOR THESE LATER PERIODS. && .AVIATION...18Z TAFS LATEST RADAR ANALYSIS SHOWING MULTIPLE LES BANDS IN AND AROUND KSBN AREA ATTM. WILL GO WITH 5SM PREVAILING TO START PERIOD...MORNING OBS HAVE HAD VSBYS NEAR 2SM WITH STRONGER BANDS SO GO WITH THIS AS TEMPO GROUP. HEAVY LES EXPECTED OVERNIGHT AS TRANSITION TO SINGLE BAND. 12Z MODELS INDICATING TIMING FOR HEAVIER SNOW AND LOWER VSBYS TO OCCUR AT KSBN BETWEEN 03Z AND 09Z AND HAVE WORDED TAF ACCORDINGLY. OTHERWISE VFR PREVAILING FOR KFWA ENTIRE PERIOD WITH JUST A TEMPO GROUP THIS AFTERNOON FOR SOME MVFR SHSN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR INZ014-015. LAKE EFFECT SNOW WARNING UNTIL 12 PM CST TUESDAY FOR INZ003-012. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST TUESDAY FOR INZ013. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR INZ005. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR INZ004. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR INZ006. MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST TUESDAY FOR MIZ077. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ079. LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUESDAY FOR MIZ078. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST TUESDAY FOR LMZ043-046. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...LASHLEY AVIATION...LOGSDON in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 243 PM CST MON NOV 17 2008 .DISCUSSION... DAYS 1-2... TEMPERATURES WILL BE THE MAIN FORECAST ISSUE FOR THE PERIOD. NORTHWESTERLY FLOW ALOFT CONTINUES THIS MORNING WITH A WEAK JET STREAK/DISTURBANCE DIGGING INTO THE OH VALLEY AND AMPLIFYING THE TROUGH. THIS HAS HELPED PUSH A COLD FRONT DOWN INTO OK AND NORTH TX, WITH NORTHEASTERLY WINDS ACROSS THE CWA. NOT MUCH WILL CHANGE INTO TONIGHT, WITH NORTHWESTERLY FLOW ALOFT CONTINUING AND SFC HIGH PRESSURE MOVING OFF TO THE EAST. UPSLOPE EASTERLY WINDS WILL CONTINUE, ALTHOUGH DEWPOINTS TO OUR EAST ARE THE SAME OR LOWER THAN WHAT WE HAVE NOW. RUC HAS SOME STRATUS FORMATION BY MORNING, BUT THE OTHER MODELS ARE QUITE A BIT DRIER. SREF HAS MINIMAL PROBS FOR CEILINGS, SO WILL LEAN TOWARDS JUST SOME MID LEVEL CLOUDS IN OUR NORTHEAST FOR NOW. LOWS WILL BE IN THE UPPER 20S TO LOW 30S. THE LEE SFC TROUGH SHOULD GET GOING AGAIN BY TOMORROW, WITH SOUTHERLY WINDS PICKING UP INTO THE 15 TO 25 MPH RANGE WITH HIGHER GUSTS. WARMER AIR WILL START TO RETURN TO OUR WESTERN COUNTIES, WITH 850MB TEMPS REACHING AROUND 20 C. THIS WILL ALLOW HIGHS IN THE WEST TO GET UP INTO THE MID 70S WHILE THE COOLER AIR HANGS ON IN THE EAST AND KEEPS READINGS IN THE LOWER 60S. THE UPPER RIDGE OVER THE WESTERN CONUS WILL START TO BREAK DOWN BY TUESDAY NIGHT AND WEDNESDAY AS ANOTHER WEAK DISTURBANCE COMES OVER THE RIDGE, WITH THE SFC TROUGH AXIS STARTING TO SHIFT EASTWARD. SOUTHERLY WINDS SHOULD CONTINUE THROUGH TUESDAY NIGHT, KEEPING LOWS IN THE UPPER 30S AND EVEN LOW 40S. THE SFC TROUGH WILL HAVE MOVED PAST BY WEDNESDAY, BRINGING A WEAK FRONT THROUGH. MOST OF THE TRULY COLD AIR WILL STILL BE TO OUR NORTH, BUT WE LOSE DOWNSLOPE AND 850MB TEMPS WILL BE KNOCKED BACK INTO THE LOWER TEENS C. SUNSHINE AND MIXING SHOULD STILL HELP US GET INTO THE MID TO UPPER 60S. DAYS 3-7... THE MEDIUM RANGE MODELS DO NOT INSTILL A LOT OF CONFIDENCE IN MAKING A FORECAST THROUGH THE EXTENDED PERIOD. ABOUT THE ONLY THING I HAVE ANY CONFIDENCE IN AT ALL IS THAT THE MEAN POSITION OF THE UPPER LEVEL RIDGE WILL REMAIN SOMEWHERE ALONG THE WESTERN COAST OF NORTH AMERICA. PER SSEC SATELLITE LOOPS...TROPICAL CONVECTION REMAINS CENTERED OVER THE INDIAN OCEAN. THIS IS PRETTY MUCH WHERE IT HAS BEEN LOCATED FOR THE PAST WEEK. UNTIL WE SEE AN EASTWARD OR EVEN A FARTHER WESTWARD SHIFT...THINK THAT THE PATTERN WILL REMAIN PRETTY MUCH THE SAME IN THIS PART OF THE WORLD. DETAILS IN THE EXTENDED PERIOD ESPECIALLY BEYOND DAYS 4/5 ARE GOING TO BE HARD TO PIN DOWN. THE MODELS HAVE BEEN STRUGGLING WITH THE STRENGTH OF THE UPPER RIDGE AND HOW UPPER LEVEL ENERGY OVERTOPS THE RIDGE AND MOVES ACROSS THE CONUS. MOST OF THE MODELS MAINTAIN FAIRLY NONDESCRIPT UPPER LEVEL NORTHWESTERLY FLOW OVER THE CONUS NEXT WEEKEND. THE ECMWF HAS BEEN MAINTAINING THE IDEA OF A WAVE DIGGING SOUTH ACROSS THE ROCKIES AND OUT INTO THE PLAINS LATE IN THE WEEKEND AND EARLY NEXT WEEK. THIS SOLUTION WOULD SUGGEST THE POTENTIAL FOR AT LEAST A SMALL CHANCE FOR PRECIPITATION. THE GFS AND CANADIAN MODELS SHOW A FAIRLY STRONG TROUGH DIVING SOUTH INTO UPPER MIDWEST AND GREAT LAKES WITH THE UPPER FLOW BECOMING FAIRLY MERIDIONAL OVER THE NORTHERN PLAINS WHICH WOULD SUGGEST A SHOT OF COLDER AIR BUT DRY. FOR NOW WILL COOL TEMPERATURES DOWN ON SATURDAY AND SUNDAY WITH NOT MUCH CHANGE MADE TO THE REST OF THE EXTENDED. SOME UNCERTAINTY AS TO THE MAGNITUDE OF THE COOLING AND FURTHER ADJUSTMENTS MAY BE NECESSARY. INTO WEEK TWO...WILL GO WITH NEAR NORMAL TEMPERATURES AND PRECIPITATION. WITH THE NORTHWEST FLOW PATTERN IN PLACE WE SHOULD OSCILLATE BETWEEN SURGES OF HIGH PRESSURE AND COOLER TEMPERATURES WITH BRIEF WARM UPS AFTER THE HIGH PRESSURE RECEDES EASTWARD. && .AVIATION... VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD. SURFACE HIGH PRESSURE WILL OVER THE NORTHERN AND CENTRAL PLAINS TODAY WILL MOVE EAST INTO THE MISSISSIPPI VALLEY ON TUESDAY WITH LOW PRESSURE DEVELOPING OVER THE NORTHERN AND CENTRAL HIGH PLAINS. THIS WILL RESULT IN A TIGHTENING PRESSURE GRADIENT AND INCREASING SOUTHERLY WINDS ON TUESDAY MORNING. && .PRELIMINARY POINT TEMPS/POPS... DDC 31 67 39 66 / 0 0 0 0 GCK 30 73 38 66 / 0 0 0 0 EHA 35 76 40 68 / 0 0 0 0 LBL 31 73 40 68 / 0 0 0 0 HYS 29 62 35 67 / 0 0 0 0 P28 30 61 40 68 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN26/02/02 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 811 PM MST SUN NOV 16 2008 .UPDATE... 808 PM MST SUN NOV 16 2008 JUST COMPLETED AN UPDATE. BACKDOOR COLD FRONT IS COMING IN A LITTLE FASTER THAN IN THE GRIDS. BASED ON UPSTREAM OBSERVATIONS AND LATEST NAM/RUC...WIND DIRECTION IS GOING TO BE A MORE EASTERLY DIRECTION AS WELL. USED NAM FOR THE UPDATE. DEWPOINTS ARE ALSO A LITTLE HIGHER AND TWEEKED THOSE AND MINS UP. SINCE DO NOT EXPECT A STRONG UPSLOPE WINDS...AND HAVE LARGE TEMP/DEWPOINT SPREADS UPSTREAM...LOOKS TO BE JUST STRATUS. SOUNDINGS AND NEW NAM SUPPORT THAT AND HAVE LESS FOG THAN EARLIER DEPICTED. BULLER && .AVIATION... 345 PM MST SUN NOV 16 2008 FOR THE 00Z TAF...WILL CONTINUE TO ADVERTISE VFR CONDITIONS THROUGH APPROX 6-8Z WHEN CONDITIONS WILL BEGIN TO DECREASE INTO THE IFR/LIFR RANGE WITH CIGS AT 200-500 FT AT BOTH KGLD/KMCK AS POST FRONTAL STRATUS MOVES IN FROM THE NORTHEAST. LITTLE CHANGE EXPECTED THROUGH 15Z BEFORE LIFTING SLIGHTLY AND BECOMING SCT005 AT KGLD AND AFTER 20Z OR SO AT KMCK...ALTHOUGH CONFIDENCE NOT HIGH ENOUGH TO BRING THEM OUT OF IFR/LIFR CIGS. RUC VIS FORECASTS CONTINUE TO SHOW WIDESPREAD AND VERY LOW CONDITIONS IN THE STRATUS WHILE THE NAM HAS A FEW SPOTS ALONG THE STRATUS LINE AS IT MOVES SOUTHWEST. WILL MAINTAIN P6SM AT PRESENT TIME AND ALERT NEXT SHIFT TO KEEP AN EYE ON THINGS ONCE THE STRATUS ACTUALLY DEVELOPS. 07 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 510 PM CST SUN NOV 16 2008 .UPDATE... THIS UPDATE IS GEARED PRIMARILY FOR AVIATION CONCERNS REGARDING THE POSSIBILITY OF LOW STRATUS DEVELOPING ACROSS WESTERN KANSAS EARLY MONDAY MORNING. THE LATEST NAM12 AND RUC13 NUMERICAL PREDICTIONS SUGGEST INCREASING POST-FRONTAL UPSLOPE WINDS AFTER ~ 06Z AS A COLD FRONT PUSHES SOUTHWEST ACROSS SOUTHWEST KANSAS. DEWPOINT TEMPERATURES NORTH OF THIS FRONT ARE HIGHER THAN SOUTH OF THE FRONT...AND THUS AS TEMPERATURES FALL INTO THE 30S OVERNIGHT...SATURATION IS POSSIBLE WITH IFR OR EVEN LIFR CEILINGS DEVELOPING. THE LOCATIONS MOST VULNERABLE TO LOW CEILING DEVELOPMENT WILL BE FAR WESTERN KANSAS...ALTHOUGH LOW CEILINGS MAY ALSO DEVELOP TOWARD GCK AND PERHAPS EVEN DDC. THERE IS A GREATER PROBABILITY OF CEILINGS DEVELOPING AT GCK VS. DDC...SO FOR THE 00Z TAFS...WILL INCLUDE AN IFR FORECAST FROM ~ 10Z TO 15Z AT GCK. HIGH LEVEL CLOUD COVER WILL COMPLICATE MATTERS...REDUCING THE AMOUNT OF POSSIBLE RADIATIONAL COOLING BEHIND THE FRONT. -UMSCHEID && .PREV DISCUSSION... /ISSUED 219 PM CST SUN NOV 16 2008/ DISCUSSION... DAYS 1-2... THE ONLY FORECAST CHALLENGE THE FIRST COUPLE OF DAYS WILL BE TEMPS ON MONDAY AS ANOTHER WEAK SURGE MOVES INTO THE AREA. THE MORNING U/A ANALYSIS SHOWED A STRONG JET STREAK DIVING SOUTHEAST ACROSS THE NORTHERN PLAINS. THE SURFACE RESPONSE WAS EVIDENT WITH A COLD FRONT MOVING SOUTH INTO NEBRASKA. THIS FRONT SHOULD BE MOVING INTO MY CWA BY SUNRISE WITH ALL OF THE AREA EXPERIENCING A NORTHERLY WIND AND CAA DURING THE DAY TOMORROW. THUS, MAX TEMPS WILL BE LOWER THAN TODAY. AS THE HIGH PRESSURE CENTER MOVES OFF ON TUESDAY, TEMPERATURES WILL MAKE A RAPID WARMUP, ESPECIALLY IN THE WEST. THE GRIDS WILL SHOW A PRETTY GOOD GRADIENT FROM WEST TO EAST ON TUESDAY WITH MID 70S EXPECTED ALONG THE COLORADO BORDER. PCPN CHANCES WILL BE VIRTUALLY NIL DURING THE NEXT 60 HOURS. DAYS 3-7... LOOKING AT THE MEDIUM AND EXTENDED RANGE MODELS, THERE WILL BE A NICE WARM UP ON TUESDAY AND POSSIBLY LINGERING INTO WEDNESDAY. AT THE START OF THE DAY 3 PERIOD, A NEAR ZONAL FLOW WILL EXIST ALOFT. THE ECMWF DEVELOPS A VERY MINOR WAVE IN THE H5 FLOW LATE THURSDAY OVER NORTH DAKOTA AND WASHES IT OUT BY LATE FRIDAY. THE GFS ON THE OTHER HAND DEVELOPS A STRONGER SHORT WAVE OVER SOUTHERN SOUTH DAKOTA THURSDAY EVENING AND DIVES IT SOUTHEAST TO ARKANSAS BY 22/00Z OR LATE FRIDAY. THE CANADIAN MODEL IS MORE IN LINE WITH THE ECMWF AND THUS DO NOT PLAN TO MENTION ANY SLIGHT POPS IN THE NORTHERN CWA THURSDAY OR FRIDAY. AT THE SURFACE, A COLD FRONT SHOULD PASS THROUGH WESTERN KANSAS THURSDAY NIGHT INTO FRIDAY, RESULTING IN A COOL DOWN. SINCE THIS FRONT IS SLOWER THAN PREVIOUSLY THOUGHT, RAISED MAX TEMPS ON BOTH WEDNESDAY AND (TO A LESSER EXTENT) THURSDAY A FEW DEGREES, ESPECIALLY IN MY SOUTHWEST ZONES WERE 850MB PROGS ARE SHOWING THE POTENTIAL FOR NEAR 70F IN THE FAR SOUTHWEST TIP OF MY CWA ON WED, AND TO PERHAPS THE MID 50S ON THURSDAY. THIS MAY PUT WEDNESDAY MAX TEMPS WARMER THAN TUESDAY`S IN SOME PLACES, MAINLY ALONG OUR SOUTHWEST BORDER WITH OKLAHOMA. BEYOND THURSDAY, SLIGHT DOWN SLOPE FLOW SUGGESTED BY ALL MODELS AND MOST SIGNIFICANTLY BY THE GFS, WILL BRING SLOWLY MODERATING TEMPERATURES THROUGH SATURDAY. MAX TEMPS WILL START FRIDAY IN THE UPPER 40S IN THE NORTHEASTERN CWA, RANGING TO THE UPPER 50S IN SOUTHWEST. BY SATURDAY, HIGHS WILL RANGE FROM THE MID 50S IN THE NORTHEAST TO THE MID 60S IN THE SOUTHWEST. WINDS MAY RETURN TO BREEZY BY FRIDAY, MAINLY THERMALLY DRIVEN AND BEGIN AFTER THE MORNING INVERSIONS BREAK. THERE WILL BE UPPER WAVES RIPPLING THROUGH SATURDAY INTO SUNDAY, BUT FOR NOW THESE APPEAR ON MODELS TO BE WELL EAST OF OUR CWA. AVIATION... VFR CONDITIONS WILL CONTINUE WITH JUST FEW HIGH CIRRUS CLOUDS, LIGHT WINDS AND NO VSBY RESTRICTIONS. && .PRELIMINARY POINT TEMPS/POPS... DDC 31 52 29 67 / 0 0 0 0 GCK 30 54 29 71 / 0 0 0 0 EHA 34 59 35 75 / 0 0 0 0 LBL 32 55 32 73 / 0 0 0 0 HYS 31 49 27 61 / 0 0 0 0 P28 34 53 29 60 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN99/99/25 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 345 PM MST SUN NOV 16 2008 .PREV DISCUSSION... /ISSUED 207 PM MST SUN NOV 16 2008/ .SHORT TERM... (TONIGHT - WEDNESDAY) 207 PM MST SUN NOV 16 2008 WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW ACROSS THE ROCKIES AND ADJACENT PLAINS THIS AFTERNOON. WEAK DISTURBANCE IN THE FLOW WAS SUPPORTING A SURFACE COLD FRONT IN THE NORTHERN PLAINS. THE FRONT WILL BACK INTO THE LOCAL AREA TONIGHT. NO PRECIPITATION IS EXPECTED WITH THE FRONT...THOUGH CLOUDS WILL INCREASE. CLOUDINESS COULD BE A FACTOR FOR MONDAY TEMPERATURES...PARTICULARLY IN EASTERN SECTIONS WHERE HAVE LEANED TOWARD COOLER GUIDANCE FOR HIGHS. WESTERN AREAS WILL SEE MORE SUN AND MAY REBOUND TO THE LOWER 60S. GUIDANCE CONTINUES TO BE QUITE WARM ON TUESDAY...WITH SOUTHWESTERLY WINDS NOW FORECAST FOR TUESDAY AFTERNOON ACROSS THE ENTIRE CWA. HAVE GONE WITH THE WARMEST GFS MOS ENSEMBLE MEMBER WITH ECMWF SUPPORT...YIELDING NEAR RECORD HIGHS IN THE MIDDLE 70S. DEW POINTS SHOULD TANK IN THE WEST...BUT DO NOT SEE MUCH WIND SO NOT EXPECTING FIRE WEATHER HIGHLIGHTS ATTM. NEXT COLD FRONT BACKS IN TUESDAY NIGHT WITH TEMPERATURES FALLING BACK TO NEAR NORMAL FOR WEDNESDAY. APPEARING MORE LIKE A GLANCING BLOW AND HAVE WARMED TEMPERATURES JUST A TAD. STILL NO SIGN OF PRECIPITATION. .LONG TERM... (THURSDAY - SUNDAY) 207 PM MST SUN NOV 16 2008 UPPER PATTERN WILL FLATTEN OUT THIS PERIOD...WITH BROAD ZONAL FLOW FORECAST ACROSS THE CONUS THROUGH SATURDAY. A TROUGH WILL DEVELOP OVER THE GREAT BASIN TOWARDS THE END OF THE PERIOD. GIVEN THE DRY WESTERLY FLOW ALOFT...NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL START BELOW NORMAL WITH THURSDAY BEING THE COLDEST DAY OF THE FORECAST PERIOD...BUT THEN WARM TO ABOVE NORMAL BY THE END OF THE WEEK AS THE COLD AIR WILL BE BOTTLED UP TO THE NORTHEAST. A WEAK COLD FRONT WILL BE FORCED SOUTHWARD BY A DISTURBANCE MOVING THROUGH THE NORTHERN PLAINS LATE IN THE PERIOD...WITH TEMPERATURES RETURNING TO NEAR NORMAL BY SUNDAY. 24 && .AVIATION... 345 PM MST SUN NOV 16 2008 FOR THE 00Z TAF...WILL CONTINUE TO ADVERTISE VFR CONDITIONS THROUGH APPROX 6-8Z WHEN CONDITIONS WILL BEGIN TO DECREASE INTO THE IFR/LIFR RANGE WITH CIGS AT 200-500 FT AT BOTH KGLD/KMCK AS POST FRONTAL STRATUS MOVES IN FROM THE NORTHEAST. LITTLE CHANGE EXPECTED THROUGH 15Z BEFORE LIFTING SLIGHTLY AND BECOMING SCT005 AT KGLD AND AFTER 20Z OR SO AT KMCK...ALTHOUGH CONFIDENCE NOT HIGH ENOUGH TO BRING THEM OUT OF IFR/LIFR CIGS. RUC VIS FORECASTS CONTINUE TO SHOW WIDESPREAD AND VERY LOW CONDITIONS IN THE STRATUS WHILE THE NAM HAS A FEW SPOTS ALONG THE STRATUS LINE AS IT MOVES SOUTHWEST. WILL MAINTAIN P6SM AT PRESENT TIME AND ALERT NEXT SHIFT TO KEEP AN EYE ON THINGS ONCE THE STRATUS ACTUALLY DEVELOPS. 07 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 207 PM MST SUN NOV 16 2008 .SHORT TERM... (TONIGHT - WEDNESDAY) 207 PM MST SUN NOV 16 2008 WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW ACROSS THE ROCKIES AND ADJACENT PLAINS THIS AFTERNOON. WEAK DISTURBANCE IN THE FLOW WAS SUPPORTING A SURFACE COLD FRONT IN THE NORTHERN PLAINS. THE FRONT WILL BACK INTO THE LOCAL AREA TONIGHT. NO PRECIPITATION IS EXPECTED WITH THE FRONT...THOUGH CLOUDS WILL INCREASE. CLOUDINESS COULD BE A FACTOR FOR MONDAY TEMPERATURES...PARTICULARLY IN EASTERN SECTIONS WHERE HAVE LEANED TOWARD COOLER GUIDANCE FOR HIGHS. WESTERN AREAS WILL SEE MORE SUN AND MAY REBOUND TO THE LOWER 60S. GUIDANCE CONTINUES TO BE QUITE WARM ON TUESDAY...WITH SOUTHWESTERLY WINDS NOW FORECAST FOR TUESDAY AFTERNOON ACROSS THE ENTIRE CWA. HAVE GONE WITH THE WARMEST GFS MOS ENSEMBLE MEMBER WITH ECMWF SUPPORT...YIELDING NEAR RECORD HIGHS IN THE MIDDLE 70S. DEW POINTS SHOULD TANK IN THE WEST...BUT DO NOT SEE MUCH WIND SO NOT EXPECTING FIRE WEATHER HIGHLIGHTS ATTM. NEXT COLD FRONT BACKS IN TUESDAY NIGHT WITH TEMPERATURES FALLING BACK TO NEAR NORMAL FOR WEDNESDAY. APPEARING MORE LIKE A GLANCING BLOW AND HAVE WARMED TEMPERATURES JUST A TAD. STILL NO SIGN OF PRECIPITATION. .LONG TERM... (THURSDAY - SUNDAY) 207 PM MST SUN NOV 16 2008 UPPER PATTERN WILL FLATTEN OUT THIS PERIOD...WITH BROAD ZONAL FLOW FORECAST ACROSS THE CONUS THROUGH SATURDAY. A TROUGH WILL DEVELOP OVER THE GREAT BASIN TOWARDS THE END OF THE PERIOD. GIVEN THE DRY WESTERLY FLOW ALOFT...NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL START BELOW NORMAL WITH THURSDAY BEING THE COLDEST DAY OF THE FORECAST PERIOD...BUT THEN WARM TO ABOVE NORMAL BY THE END OF THE WEEK AS THE COLD AIR WILL BE BOTTLED UP TO THE NORTHEAST. A WEAK COLD FRONT WILL BE FORCED SOUTHWARD BY A DISTURBANCE MOVING THROUGH THE NORTHERN PLAINS LATE IN THE PERIOD...WITH TEMPERATURES RETURNING TO NEAR NORMAL BY SUNDAY. 24 && .AVIATION... 1020 AM MST SUN NOV 16 2008 FOR THE 18Z TAF...FIRST 15 HOURS OR SO OF THE TAF PERIOD WILL BE VFR AT BOTH KGLD AND KMCK AS MAINLY MID AND HIGH LEVEL CLOUDINESS MOVES INTO THE AREA FROM THE NORTHWEST. BY 09Z CONDITIONS MAY DROP TO IFR/LIFR WITH CIGS AT 200 FT AT KMCK THEN KGLD BY 11Z (COULD BE A FEW HOURS SOONER AS MODELS USUALLY UNDERDO STRATUS DEVELOPMENT AND MOVEMENT) AS POST FRONTAL STRATUS MOVES IN FROM THE NORTHEAST. THIS WILL CONTINUE THROUGH AT LEAST 15Z BEFORE LIFTING SLIGHTLY TO 500 FT BY THE END OF THE TAF PERIOD. FOR NOW HAVE GONE WITH A SCATTERED DECK BETWEEN 200 AND 500 FT AS GFS BOUNDARY LAYER RH NOT QUITE AS HIGH AS THE RUC AND NAM. RUC VISIBILITY FORECASTS SHOW NEAR ZERO VISIBILITY WHILE THE NAM SHOWS LITTLE IN THE WAY OF RESTRICTION...SIMILAR TO THE VARIOUS MOS AND LAMP GUIDANCE VALUES. SOMETHING ELSE TO WATCH FOR THE 00Z TAF ISSUANCE. 07 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 1020 AM MST SUN NOV 16 2008 .PREV DISCUSSION... /ISSUED 425 AM MST SUN NOV 16 2008/ .DISCUSSION... 107 AM MST SUN NOV 16 2008 A COLD FRONT MOVING SOUTH OVER THE NORTHERN PLAINS MAY BACK INTO THE NORTHEAST ZONES LATE IN THE PERIOD WHILE A LARGE AREA OF MID CLOUDS ARE ON A VERY CLOSE TRAJECTORY WITH THE NORTHEAST FRINGE OF THE FORECAST AREA. CONCERNS FOR LIMITED INSOLATION/WESTWARD EXTENT OF FROPA WILL RESULT IN A DOWNWARD TREND IN MAXIMUM TEMPERATURES ACROSS THE NORTHEAST ZONES TODAY. FURTHER WEST...MAXIMUM TEMPERATURES MAY APPROACH 70 IN SOME LOCATIONS. DRY FROPA STILL EXPECTED THROUGH TONIGHT WITH MAXIMUM TEMPERATURES ON MONDAY STRUGGLING TO CLIMB OUT OF THE 40S ON THE EASTERN PERIPHERY OF THE FORECAST AREA. MID/UPPER RIDGE WILL TRANSLATE EAST ON TUESDAY AS LOW LEVEL THERMAL RIDGE EXPANDS ACROSS THE CENTRAL HIGH PLAINS. CONTINUED TO TREND MAXIMUM TEMPERATURES UP WITH RECORD/NEAR RECORD VALUES ANTICIPATED. SIGNIFICANT CHANGES WERE NOT MADE BEYOND DAY 3. && .AVIATION... 1020 AM MST SUN NOV 16 2008 FOR THE 18Z TAF...FIRST 15 HOURS OR SO OF THE TAF PERIOD WILL BE VFR AT BOTH KGLD AND KMCK AS MAINLY MID AND HIGH LEVEL CLOUDINESS MOVES INTO THE AREA FROM THE NORTHWEST. BY 09Z CONDITIONS MAY DROP TO IFR/LIFR WITH CIGS AT 200 FT AT KMCK THEN KGLD BY 11Z (COULD BE A FEW HOURS SOONER AS MODELS USUALLY UNDERDO STRATUS DEVELOPMENT AND MOVEMENT) AS POST FRONTAL STRATUS MOVES IN FROM THE NORTHEAST. THIS WILL CONTINUE THROUGH AT LEAST 15Z BEFORE LIFTING SLIGHTLY TO 500 FT BY THE END OF THE TAF PERIOD. FOR NOW HAVE GONE WITH A SCATTERED DECK BETWEEN 200 AND 500 FT AS GFS BOUNDARY LAYER RH NOT QUITE AS HIGH AS THE RUC AND NAM. RUC VISIBILITY FORECASTS SHOW NEAR ZERO VISIBILITY WHILE THE NAM SHOWS LITTLE IN THE WAY OF RESTRICTION...SIMILAR TO THE VARIOUS MOS AND LAMP GUIDANCE VALUES. SOMETHING ELSE TO WATCH FOR THE 00Z TAF ISSUANCE. 07 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAKE CHARLES LA 743 PM CST MON NOV 17 2008 .UPDATE...THE REINFORCING CANADIAN COLD FRONT IS CROSSING INTO THE TEXAS SIDE OF THE RED RIVER. THE LATEST RUC AND NAM GUIDANCE HAS THE FRONT THROUGH THE I-10 CORRIDOR BY SUNRISE. STILL LOOKING DRY. A FAIRLY DECENT THERMAL GRADIENT WAS NOTED IN THE WAKE OF THIS FRONT. TRIMMED MORNING TEMPS DOWN 1 TO 2 DEGREES TO ACCOUNT FOR THIS FOR MOST AREAS EXCEPT CENTRAL LOUISIANA. && .MARINE...BRIEF INCREASE IN WINDS MONDAY MORNING TO JUST SHY OF SCA CRITERIA WITH THE FRONTAL PASSAGE. WILL HEADLINE COASTALS WITH SCEC ON TUESDAY. && SWEENEY && .AVIATION...CLEAR. && K. KUYPER .MARINE...BRIEF INCREASE IN WINDS MONDAY MORNING TO JUST SHY OF SCA CRITERIA WITH THE FRONTAL PASSAGE. WILL HEADLINE COASTALS WITH SCEC ON TUESDAY. && .PREV DISCUSSION... /ISSUED 303 PM CST MON NOV 17 2008/ DISCUSSION... WEAK PRESSURE GRADIENT OVER THE REGION PROVIDING LIGHT AND VARIABLE WINDS OVER THE REGION. VIS SAT IMAGERY SHOWS NOT A CLOUD TO BE SEEN...WITH A SMALL SMOKE PLUME ACROSS COASTAL SE CAMERON PARISH NEAR ROCKEFELLER WILDLIFE REFUGE. NEXT RE-ENFORCING FRONT JUST NORTH OF THE RED RIVER IN OK THIS AFTERNOON. THE FRONT AND SFC HIGH WILL FILTER ACROSS THE REGION OVERNIGHT...WITH A STRONGER NE FLOW EXPECTED ON TUE. WITH THE WIND EXPECTED TO STAY UP AFTER FROPA...LOTS OF MIXING WILL BE OCCURRING ..WITH LOWS BEING ATTAINED MAINLY FROM THE CAA TUE MORNING. WITH ABSOLUTELY NO MOISTURE POOLING OR LIFT AHEAD OF THE FRONT...0% CHANCE OF PRECIPITATION IS EXPECTED. WITH CAA EXPECTED TO CONTINUE TUE AFTERNOON...HIGHS WILL MAINLY BE HELD TO THE UPPER 50S ACROSS C LA...TO THE LOWER/MID 60S ELSEWHERE. WITH THE MAIN EMPHASIS OF THE HIGH TOWARDS THE SOUTHEASTERN U.S...LOW TEMPS WED WILL BE COOLEST ACROSS C LA WITH MID 30S EXPECTED...TO ABOUT 10 DEGREES WARMER ACROSS SE TX. AS THE HIGH MOVES FURTHER EAST WED AND THU...TEMPS WILL BE MODERATING AS WELL. NO PRECIP IS EXPECTED THOUGH. THE PERIOD OF FRI THROUGH MON IS A LOW CONFIDENCE FORECAST...WITH THE ECMWF & GFS RUNNING ALMOST 180 DEGREES OUT OF PHASE WITH THEIR OUTPUT THE LAST SEVERAL RUNS. THIS OF COURSE IS GIVING A VARIED RANGE OF SOLUTIONS. PREVIOUS FORECAST...AS WELL AS SURROUNDING OFFICES...HAVE TRENDED TO THE LESS VOLATILE ECMWF SOLUTION...WHICH LEAVES LINGERING MOISTURE AND THE SLIGHT CHANCE OF RAIN THIS WEEKEND. DML MARINE... LIGHT N-NE FLOW WILL INCREASE AFTER MIDNIGHT WITH THE NEXT SFC HIGH MOVING SSE OVER MAINLY THE EASTERN U.S. WILL MAINLY SEE NE FLOW FROM THIS EVENT ON TUE...WITH WINDS MAINLY 10-15 KTS ACROSS THE INLAND LAKES AND BAYS...15 KTS ACROSS THE 0-20NM COASTAL WATER ZONES...AND 15-20 KTS ACROSS THE 20-60NM ZONES. NOT EXPECTING SCA CONDITIONS WITH THIS SYSTEM. DML && .PRELIMINARY POINT TEMPS/POPS... KLCH 43 62 43 68 50 / 0 0 0 0 0 KBPT 44 65 45 70 54 / 0 0 0 0 0 KAEX 41 57 35 64 46 / 0 0 0 0 0 KLFT 40 61 39 67 48 / 0 0 0 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$ DML la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 741 PM EST MON NOV 17 2008 .SYNOPSIS... A COLD FRONT PUSHES OFFSHORE TONIGHT. STRONG HIGH PRESSURE WILL BUILD INTO THE MIDWEST ON TUESDAY...THEN SLOWLY MOVE EAST INTO THE MID ATLANTIC REGION BY WEDNESDAY. ANOTHER COLD FRONT WILL PUSH THROUGH THE AREA THURSDAY. BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH AT LEAST THE END OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... TROUGH ALOFT AMPLIFYING SHARPLY INTO THE ERN STATES OVRNGT...LEADING TO A PD OF STRNG CAA (BEGINNING OVRNGT). INITIAL PUSH OF LLVL CAA ENTERING FAR WNW AREAS THIS EVE...TO CONT TO PASS THROUGH THE REST OF THE FA OVRNGT. UPR LVL JET MAX (NR 140KT AT 300MB ON LATEST RUC13) PASSING ACRS XTRM NRN NC/SRN VA THROUGH ABT 04-06Z/18. MUCH OF FA IN RFQ OF THAT JET...AND THAT WL LEAD TO CONTD BKN/OVC (HIER LVL) CLDNS THRUT MUCH OF VA/MD CTYS IN FA. DRY LLVLS (OVR THE RGN) AND UVM SUPPORT NEC FOR AT LEAST SCTD PCPN THROUGH THIS EVE SHOULD RMN W AND N. WL NEED TO MONITOR PD FM LT EVE THROUGH OVRNGT HRS ACRS MNLY NRN HALF OF FA (GENLY ALG N OF LKU-WAL LN) FOR BETTER PCPN CVRG. SNDGS FM NNE SXNS OF FA SUGG PTNTL LWRG OF WET BULB ZERO HGT BLO 1KFT AFT MDNGT...PTNTLLY LEADING TO PD OF SNSH THOSE AREAS. KPG POPS AT 50%...ESP ON THE LWR MD ERN...W/ ANY XPCTD ACCUMS AOB 1/2 IN. ELSW (ACRS SXNS OF CNTRL/SRN VA)...SLGT CHC POPS (FOR SHRAS...B4 PSBL FLURRIES LT). LO TEMPS IN THE 30S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... STRNG/DP LYRD CAA XPCTD OVR FA DURG TUE...W/ STRNGLY ANOMALOUS UPR LVL LO PRES PASSING ACRS NCTNRL VA DURG MIDDAY...TO THE DELMARVA CST TWD EVE. VRY STEEP LAPSES FCST THRUT THE RGN FOR THE MIDDAY/ERY AFTN HRS...W/ ENUF INSTABILITY...ESP CNTRL/ERN SXNS...FOR AT LEAST BKN CIGS ARND 5-7KFT...20/30% POPS (MNLY SNSH) AND GSTY WNDS. H85 TEMPS PLUNGING TO BTWN -8 AND -10 DEGS C...AND DVLPG NNW LLVL AIR TRAJ INVOF BAY/CST (WHR WTR TEMPS +10 TO +13 DEGS C) - NRLY 20 TO 25 DEGS DELTA T...SHOULD GENERATE CONTD CHCS FOR SNSH (OR BAY/OCN STREAMERS) INTO AT LEAST 1ST PART OF TUE NGT (FAVORING PORTIONS OF HAMPTON RDS TO OTR BNKS). WND SPDS AVGG 15 TO 25 MPH ACRS MUCH OF FA TUE...GUSTS AOA 30 MPH QUITE PSBL...COMBINED W/ TEMPS NO BETTER THAN U30S-L40S...RESULTING IN WND CHILLS LRGLY IN 20S...DEFINITELY A MESSAGE THAT WINTER IS IN THE WAY. WL NEED TO WATCH PSBL OCN STM DVLPMNT E OF MDATLC RGN LT TUE/TUE NGT WHICH WOULD PROLONG HIER WNDSPDS INVOF CST...ALG W/ PSBL CONTD LLVL CLD CVRG. SFC HI PRES FM THE W BUILDS IN THE RGN ON WED. LLVL MIXING TO RMN LMTD AS RDG AXIS SLO TO CRS THE RGN DURG THE AFTN HRS. LLVL FLO AND WAA (AT LEAST ABV BLYR) BEGINS WED NGT (DCPLD LLVLS WL RESULT IN ANOTHER COLD NGT...EVEN TO THE CST...W/ PSBL BEST SHOT AT A FZ INVOF ORF/VA BCH TO OTR BNKS NC. BETTER (SFC) MIXING (AND CORRESPONDING MILDER SFC TEMPS - U40S- L50S) XPCTD THU. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LONG TERM PATTERN CONTINUES TO BE DOMINATED BY UPR TROF OVER THE EASTERN U.S...AND GENERALLY BLO NORMAL TEMPS DURING DAYS 4 TO 7. FRI/SAT EXPECTED TO BE COLD AND DRY. NEXT FNTL SYSTEM FCST TO MOVE THROUGH SUNDAY INTO MONDAY. SOME MODERATION IN TEMPS /CLOSER TO NORMAL/ LIKELY SUNDAY...ALTHOUGH THERE MAY BE ENOUGH CLOUDINESS TO TEMPER WARMING. ATTM...WILL HAVE A SILENT 20 PCT POP IN THE SUNDAY NIGHT/MONDAY TIME FRAME...AS THERE IS CONSIDERABLE DIFFERENCES BETWEEN GFS AND ECMWF WITH REGARD TO HOW THEY HANDLE THIS FROPA...WITH GFS DRIER. DEPENDING UPON TIMING OF FROPA...MONDAY COULD BE JUST AS WARM AS SUNDAY...AND HAVE SHADED TEMPS TO THIS THINKING. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... A COLD FRONT AT 00Z EXTENDS FROM DELAWARE SOUTHWEST ACROSS CENTRAL VIRGINIA JUST NORTHWEST OF RIC. THIS FRONT WILL CONTINUE MOVING SE THROUGH THE AREA...SHIFTING SURFACE WINDS TO NW. BEHIND THE FRONT...SCATTERED SHOWERS WERE TAKING PLACE AND AS TEMPERATURES ALOFT DROP OVERNIGHT...PRECIPITATION WILL CHANGE TO SNOW SHOWERS. THESE WILL BE MOST LIKELY IN THE SBY AREA WHERE THE SNOW WILL CAUSE MVFR VISIBILITIES...BRIEFLY DROPPING TO IFR. THE REST OF THE AREA WILL EXPERIENCE JUST LIGHT PRECIPITATION WITH CONDITIONS REMAINING VFR. IN THE SE PART OF THE AREA...SNOW SHOWERS ARE EXPECTED TO INCREASE IN THE AFTERNOON TUE...ESPECIALLY AT ORF...ON THE BACK SIDE OF A DEVELOPING OFFSHORE STORM SYSTEM. SOME BAY EFFECT SNOW SHOWERS ARE POSSIBLE...DEPENDING ON THE WIND DIRECTION. AT THIS TIME IT APPEARS THEY WILL MAINLY AFFECTING THE LOWER EASTERN SHORE OF VIRGINIA. GUSTY NORTHWEST TO NORTH WINDS WILL DEVELOP DURING THE DAY TUE... ESPECIALLY IN EASTERN PORTIONS WITH A FORECAST 15 KNOTS WITH GUSTS TO 25. ANY LEFTOVER FLURRIES WILL END TUE EVENING AS HIGH PRESSURE BUILDS IN FOR THE REST OF THE WEEK. A FRONTAL PASSABE LATE THU LOOKS DRY AT THIS TIME...CONDITIONS SHOULD REMAIN VFR FOR THE REMAINDER OF THE WEEK. && .MARINE... NEXT SEVERAL DAYS TO BE GENERALLY UNFAVORABLE TO BOATING ACTIVITY ACROSS CWA. RELATIVELY CALM CONDITIONS TODAY WILL BE REPLACED BY WINDY AND COLDER CONDITIONS TUESDAY INTO WEDNESDAY...DUE TO THE COMBINATION OF STRONG COLD FRONTAL PASSAGE...COLD ADVECTION AND OFFSHORE CYCLOGENESIS. HAVED RAISED A GALE WARNING ACROSS THE BAY...AS LATEST MODEL GUIDANCE...SPCLY NAM...INDICATE WIND GUSTS TO GALE FORCE. WINDS WILL BE SLOW TO DIMINSH BELOW SCA CRITERIA...AS OFFSHORE STORM TAKES ITS TIME MOVING AWAY FROM THE U.S. EXPECT MORE BENIGN MARINE WEATHER ON THURSDAY...WITH YET ANOTHER INCREASE IN WINDS FRI/SAT AS YET ANOTHER SURGE OF COLD AIR MOVES INTO REGION. LATEST GFS/MOSGUIDE WINDS APPEAR TO UNDER FORECAST WIND SPEEDS...AND HAVE SIDED CLOSELY WITH HPC GUIDANCE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 1 PM EST TUESDAY FOR ANZ630>632. GALE WARNING FROM 1 PM TUESDAY TO 11 AM EST WEDNESDAY FOR ANZ630>632-650-652-654-656-658. SMALL CRAFT ADVISORY FROM 1 AM TUESDAY TO 11 AM EST WEDNESDAY FOR ANZ633. SMALL CRAFT ADVISORY FROM 1 AM TO 1 PM EST TUESDAY FOR ANZ650- 652-654-656-658. && $$ SYNOPSIS...ALB NEAR TERM...ALB SHORT TERM...ALB LONG TERM...WRS AVIATION...LSA MARINE...WRS md AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1000 PM EST MON NOV 17 2008 .UPDATE... SUBSIDENCE IN THE WAKE OF SHORTWAVE MOVING THRU LWR MI AND SFC HIGH PRES BUILDING E FROM WRN MN WILL SPELL A WEAKENING TREND IN LES OVERNIGHT. 00Z CWPL/KINL SOUNDINGS SHOW EXPECTED LOWERING INVERSIONS NICELY WITH KINL SOUNDING REPRESENTING A MORE HOSTILE ENVIRONMENT FOR LES WITH LOWER INVERSION AROUND 865MB/4.4KFT MSL AND A WELL MIXED BOUNDARY LAYER. RADAR NEAR THUNDER BAY ONTARIO HAS ALSO SHOWN A RAPID DIMINISHING OF LES OFF LAKE NIPIGON THIS EVENING. SO...GOING FCST OF ENDING ADVY FAR W OVERNIGHT LOOKS ON TRACK. OVER THE W... LOCALIZED CONVERGENCE BTWN ONTONAGON (NW WIND) AND UPPER ENTRANCE OF PORTAGE CANAL (NE WIND) HAS BEEN FOCUSING HEAVIER SNOW THIS EVENING IN FAR NRN ONTONAGON COUNTY TO THE NE OF ONTONAGON...AROUND THE HOUGHTON COUNTY LINE. THAT MAY CONTINUE FOR A FEW MORE HRS. TO THE E...ALTHOUGH OVERALL ENVIRONMENT WILL BECOME LESS FAVORABLE FOR LES...LAND BREEZES SHOULD DEVELOP STRONGER TONIGHT UNDER DECREASING SYNOPTIC WIND REGIME AND COOLER INTERIOR. LOCAL HIGH RES WRF-ARW AND ESPECIALLY THE 00Z RUC SHOW LOW-LEVEL CONVERGENCE STRENGTHENING THRU THE NIGHT INTO NCNTRL UPPER MI...BECOMING MORE TIGHTLY FOCUSED BTWN MARQUETTE AND DEERTON BY LATE IN THE NIGHT. THIS WILL WORK TO OFFSET THE NEGATIVE FACTORS LOCALLY. DOMINANT BAND IN THAT AREA WILL ALSO BENEFIT FROM PRECONDITIONING OFF LAKE NIPIGON. GOING FCST HAS THIS COVERED WELL...SO NO HEADLINE CHANGES ARE WARRANTED FOR THE CNTRL PORTION OF THE FCST AREA. FARTHER E...IT APPEARS SOME DECENT SNOW IS FALLING IN PORTIONS OF LUCE COUNTY THOUGH PERSISTENT BANDING IS NOT EVIDENT. SINCE LAND BREEZE OFF ONTARIO SHOULD VEER WINDS A BIT MORE NE OVER THE FAR ERN PART OF LAKE SUPERIOR...-SHSN SHOULD TEND TO DIMINISH WITH BULK OF HEAVIER SHSN SHIFTING W OF LUCE COUNTY DURING THE NIGHT. && .SYNOPSIS... ISSUED AT 432 PM EST 20Z WATER VAPOR LOOP AND RUC ANALYSIS SHOWED A POSITIVE PNA PATTERN WITH STRONG RIDGING ACROSS THE WESTERN U.S. INTO SW CANADA AND TROUGHING ACROSS EASTERN CANADA INTO THE GREAT LAKES. BETWEEN THE TROUGH AND RIDGE...A 120-140 KT JET AROUND 200MB EXTENDS FROM NORTHERN SASKATCHEWAN INTO SW MN. WITHIN THE UPPER TROUGH...THE MOST IMPORTANT FEATURE IN THE SHORT TERM IS A SHRTWV CROSSING NE WI. 12Z INL SOUNDING...WHICH WAS SITUATED SOMEWHAT CLOSE TO THE SHRTWV BACK AT 12Z...SHOWED A NEARLY SATURATED PROFILE FROM THE SFC TO 600MB... ALONG WITH TEMPS MOSTLY BELOW -10C THROUGH THIS LAYER. THIS COLD AIR CROSSING LAKE SUPERIOR CONTINUES TO GENERATE LAKE EFFECT SNOW SHOWERS...ESPECIALLY GIVEN THAT LAKE SURFACE TEMPERATURES ARE RUNNING 5-6C. BANDS WERE ORGANIZED THIS MORNING...PARTICULARLY OVER ERN MARQUETTE AND WRN ALGER COUNTIES WHERE OVER THE HIGHER TERRAIN SNOWFALL RATES WERE 1-1.5 INCHES PER HOUR. LOCATIONS NEAR THE SHORELINE WERE RUNNING A LITTLE LESS THAN THAT...DUE TO PROXIMITY OF THE WARMER LAKE PRODUCING MORE SMALLER SNOWFLAKES COMPARED TO THE DENDRITES OVER THE HIGHER TERRAIN. HOWEVER...DAYTIME HEATING DISRUPTED THE BANDS FOR EARLY THIS AFTERNOON. NOW THAT THE SUN IS SETTING...VISIBLE SATELLITE IMAGERY IS STARTING TO INDICATE A SINGLE BAND FORMING FROM LAKE NIPIGON...THROUGH CENTRAL LAKE SUPERIOR...TO MARQUETTE AND INTO NW LOWER MI. THIS IS DUE TO A NNE FLOW ON EASTERN LAKE SUPERIOR IMPINGING ON NW FLOW ACROSS THE WESTERN HALF OF THE CWA. TO THE WEST...1037MB HIGH PRESSURE CAN BE SEEN OVER THE PLAINS. DRIER AIR FROM THIS HIGH IS GRADUALLY MAKING IN ROADS INTO THE WESTERN CWA...NOTED BY DEWPOINTS AROUND 10F AT CMX AND IWD. THIS DRIER AIR HAS KEPT THE LAKE EFFECT FROM BEING AS HEAVY OVER WESTERN UPPER MI. LAST ITEM TO NOTE IS A SHRTWV COMING INTO THE NW BRITISH COLUMBIA COAST...WHICH IS THE NEXT SYSTEM TO AFFECT THE CWA. SNOWFALL AMOUNT WISE...LOCATIONS OVER THE HIGHER TERRAIN OF WESTERN ALGER COUNTY HAVE ALREADY SEEN OVER A FOOT SINCE LAST EVENING...WITH A REPORT FROM TRENARY AROUND 19 INCHES. MORE REPORTS CAN BE SEEN ON THE LATEST ARBLSRMQT. && .SHORT TERM (TONIGHT AND TUESDAY)... ISSUED AT 432 PM EST AS THE NW BRITISH COLUMBIA SHRTWV MOVES EAST OVER THE NEXT 24 HOURS...IT WILL PUSH THE SW CANADA RIDGE TOWARDS THE GREAT LAKES...MORE FLATTENING IT OUT WITH TIME. THIS MEANS MUCH OF THE WARM AIR ASSOCIATED WITH THE RIDGE IS EXPECTED TO STAY AWAY FROM HERE. HOWEVER...THE PROGRESSION OF THE RIDGE WILL ALLOW THE AREA OF HIGH PRESSURE OVER THE PLAINS TO CROSS UPPER MICHIGAN DURING THE DAY TUESDAY...ALLOWING LAKE EFFECT TO END WEST TO EAST. UNTIL THEN... TONIGHT APPEARS NOW OF MOSTLY MULTI-PARALLEL BANDS COMING OFF LAKE SUPERIOR...DUE TO SUBSIDENCE IN THE WAKE OF THE NE WI SHRTWV AND MOSTLY UNIDIRECTIONAL NORTH FLOW. IT IS POSSIBLE THAT SOME OF THE BANDS COULD BECOME STATIONARY...WHICH MEANS UPSLOPE AREAS SUCH AS IN MARQUETTE AND ALGER COUNTIES WITH THE LONGER FETCH OFF LAKE SUPERIOR COULD END UP WITH 5 INCHES OF 20-25 TO 1 SNOW. IN ADDITION...SINCE WE ARE GOING INTO THE DIURNAL MINIMUM WHEN LAND BREEZES ARE FAVORED...A STRONGER SINGLE BAND IS NOT OUT OF THE QUESTION. THEREFORE...AT LEAST THE WARNINGS FOR MQT..ALGER AND NRN SCHOOLCRAFT COUNTIES SEEM REASONABLE. FOR WESTERN UPPER MI...DRIER AIR SHOULD KEEP THE LAKE EFFECT TO A MINIMUM...THOUGH EXTRA CONVERGENCE IN THE GOGEBIC/ONTONAGON COUNTY AREA EXPECTED THIS EVENING MAY ALLOW FOR A LITTLE EXTRA SNOW AND THEREFORE EXTENDED THE ADVISORY. GOING LOW TEMPERATURES LOOKED REASONABLE. FOR TUESDAY...AGAIN LAKE EFFECT SNOW EXPECTED TO DIMINISH WEST TO EAST AS INVERSIONS LOWER...WINDS BACK AND DRIER AIR MOVES IN WITH THE HIGH PRESSURE AREA. IN FACT...MUCH OF THE WEST HALF OF THE CWA SHOULD BE DRY FOR THE AFTERNOON. WITH GRADUAL WARMING OF 850MB TEMPS...FROM AROUND -14C NOW TO -12C TUE AFTN...TOMORROW SHOULD END UP SLIGHTLY WARMER THAN TODAY. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... SFC RDG AXIS WL BE OVER THE ERN U.P. AT 00Z TUE...BUT WAD CLD WL BE SPILLING IN FM THE W AHEAD OF NEXT SHRTWV SPILLING OVER THE RDG IN THE PLAINS. ALTHOUGH THE LLVLS WL BE INITIALLY DRY...THE ISENTROPIC LIFT SHOWN ON THE 280-295K SFCS/H85-5 QVECTOR CNVGC APPEARS SUFFICIENTLY STRONG TO GENERATE PCPN...ESPECIALLY OVER THE NE HALF OF THE FA WHERE PARCELS WL HAVE A LONGER PD OF UPGLIDE TO SATURATE AND WHERE FLOW OFF LK MI WL ACCENTUATE MOISTENING ACRS THE ERN ZNS. GFS MOS GUIDANCE SEEMS TO HAVE THE BEST HANDLE ON POPS. IN FACT... NAM/GFS QPF IS QUITE A BIT HIER OVER THE FAR ERN ZNS WHERE THERE IS LIKELY TO BE SOME LK ENHANCEMENT OF THE SHSN (H85 TEMPS FCST ARND -9C VS WATER TEMP ARND 8C) AFT 06Z IN SSW FLOW OVER THE LENGTH OF LK MI. NAM/GFS FCST SDNGS FOR ERY ALSO SHOW AN ALMOST 10K FT DEPTH OF LYR WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH IN THE 06Z-12Z TIME FRAME. ELECTED TO BUMP UP POP TO HI CHC/LIKELY IN THIS AREA ABV MOS GUIDANCE. CLIPPER LO PROGGED TO SHIFT INTO ERN LK SUP BY 00Z THU. POTENTIAL FOR LK ENHANCED SHSN WL LINGER ON WED MRNG OVER THE FAR E...BUT VEERING FLOW TO W LATER IN THE DAY WL END THE THREAT. LATER SHIFTS MAY NEED TO CONSIDER AN ADVY FOR PORTIONS OF THE ERN ZNS BEFORE THE LK ENHANCED SN DIMINISHES THERE. WL INCLUDE MENTION IN HWO. OTRW... THREAT FOR LARGER SCALE PCPN WL END W-E WL LOSS OF ISENTROPIC LIFT AND MID LVL DRY SURGE UNDER UPR JET AXIS THAT WL CUT OFF LLVL MSTR FM DENDRITIC SN GROWTH LYR. OTRW...ARRIVAL OF CYC NW FLOW LATE IN THE DAY WL CAUSE SOME LES TO DVLP OVER THE W...BUT AIRMASS DOES NOT APPEAR SUFFICIENTLY COLD UNTIL LATE FOR SGNFT LES (H85 TEMP ARND -6C OVER WRN LK SUP AT 18Z FALLS TO -10C AT 00Z THU) WITH RELATIVELY SHALLOW MSTR BLO DGZ. EXPECT INCRSG LES ON WED NGT/THU WITH STRENGTHENING NNW FLOW BTWN DEPARTING CLIPPER LO AND ARCTIC HI PRES BLDG INTO SCNTRL CAN DRIVING H85 TEMPS AS LO AS -17C OVER LK SUP BY 00Z FRI. MODELS SHOW H925 WINDS BTWN 330-350 OR SO AND UP TO 30 KTS...WL HIT THE POPS UP HIEST IN THOSE AREAS FVRD BY THAT WIND DIRECTION. AT SOME POINT...A HEADLINE FOR LES WL LIKELY BE NECESSARY IN THESE FVRD AREAS WITH FCST SDNGS SHOWING CONSIDERABLE OMEGA WITHIN THE DGZ. WL MENTION IN THE HWO FOR NOW. WITH FALLING H85 TEMPS ON THU...EXPECT LTL DIURNAL RECOVERY IN TEMP. ONGOING LES/GUSTY WINDS ON THU NGT WL BEGIN TO DIMINISH W-E ON FRI WITH APRCH OF SFC RDG AXIS. PER NCEP GUIDANCE...TENDED TO FOLLOW THE QUICKER 00Z ECMWF/CNDN MODELS AND 12Z ECMWF FOR TIMING ARRIVAL OF RDG AXIS FM THE W AND ENDING OF THE LES. AS NEXT CLIPPER SHRTWV APRCHS FM THE W ON FRI NGT/SAT/SAT NGT...A STRONG WAD PATTERN WL SET UP ACRS THE UPR LKS TO THE NW OF DEPARTING SFC RDG AXIS. WL CARRY CHC POPS FOR -SN...WITH THE HIER POPS OVER NRN LK SUP/THE ERN FA CLOSER TO TRACK OF SFC LO PROGGED ACRS SRN ONTARIO AND WHERE THERE MAY BE SOME MOISTENING OFF LK MI. ANY SYNOPTIC SCALE SN WL END ON SUN WITH PASSAGE OF CLIPPER AND TRANSITION TO LES INTO MON WITH COLD AIR INFUSION (00Z ECMWF SHOWS H85 TEMP FALLING TO ARND -15C BY 12Z MON) IN THE WAKE OF CLIPPER LO. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KCMX...EXPECT VARYING CONDITIONS DURING THE EVENING AS INTERMITTENT -SHSN PASS OVER THE AREA. DUE TO SHADOWING FROM ISLE ROYALE UNDER NNW WINDS...LAKE EFFECT -SHSN SHOULD BE FAIRLY LIGHT. EXPECT PREVAILING CONDITIONS TO BE VFR WITH OCCASIONAL MVFR THOUGH IT`S CERTAINLY NOT OUT OF THE QUESTION THAT BRIEF IFR VIS COULD STILL OCCUR AT TIMES. VFR CONDITIONS SHOULD BE THE RULE OVERNIGHT WITH CIGS FALLING TO MVFR LATE IN THE NIGHT THRU TUE MORNING AS SUBSIDENCE INVERSION LOWERS. AS WINDS BACK SW LATE TUE AFTN...VFR CONDITIONS WILL DEVELOP. AT KSAW...UNDER NRLY WINDS...EXPECT WIDE SWINGS IN CONDITIONS AS LONG FETCH ACROSS THE LAKE AND UPSLOPING RESULT IN HEAVIER SNOW SHOWERS AT TIMES. WHILE PREVAILING CONDITIONS SHOULD BE MVFR... HEAVIER SNOW SHOWERS WILL LIKELY RESULT IN PERIODIC IFR/LIFR CONDITIONS INTO THE OVERNIGHT. LATE IN THE NIGHT...LOWERING SUBSIDENCE INVERSION WILL LEAD TO DIMINISHING -SHSN WITH MVFR CONDITIONS BECOMING THE RULE. FURTHER IMPROVEMENT TO VFR EXPECTED EARLY TUE AFTN AS WINDS BACK W THEN SW. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... NORTH WINDS OF UP TO 30 KNOTS WILL DIMINISH TONIGHT INTO TUE MORNING AS A RIDGE OF HIGH PRESSURE CROSSES LAKE SUPERIOR. HOWEVER...ANOTHER LOW PRESSURE AREA REACHING NORTH DAKOTA TUESDAY EVENING IS EXPECTED TO CROSS JUST NORTH OF LAKE SUPERIOR ON WEDNESDAY...AND THEN MOVE TO THE LOWER GREAT LAKES BY THURSDAY. IN ITS WAKE FOR THURSDAY...A PERIOD OF NORTHERLY GALES TO 35 KNOTS IS POSSIBLE ON THURSDAY AS COLD AIR FLOWS SOUTH. FOR THURSDAY NIGHT INTO SATURDAY...ANOTHER RIDGE OF HIGH PRESSURE OVER THE PLAINS WILL BUILD BACK INTO UPPER MICHIGAN...BRINGING WINDS BACK DOWN BELOW GALES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUE MIZ005-006-085. LAKE EFFECT SNOW ADVY UNTIL 1 AM EST /MIDNIGHT CST/ TUE MIZ002-009. LAKE EFFECT SNOW ADVY UNTIL 7 AM EST TUE MIZ013. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SYNOPSIS/SHORT TERM DISCUSSION...AJ LONG TERM DISCUSSION...KC AVIATION...ROLFSON MARINE...AJ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 645 PM EST MON NOV 17 2008 UPDATED AVIATION DISCUSSION FOR 00Z TAF ISSUANCE .SYNOPSIS... ISSUED AT 432 PM EST 20Z WATER VAPOR LOOP AND RUC ANALYSIS SHOWED A POSITIVE PNA PATTERN WITH STRONG RIDGING ACROSS THE WESTERN U.S. INTO SW CANADA AND TROUGHING ACROSS EASTERN CANADA INTO THE GREAT LAKES. BETWEEN THE TROUGH AND RIDGE...A 120-140 KT JET AROUND 200MB EXTENDS FROM NORTHERN SASKATCHEWAN INTO SW MN. WITHIN THE UPPER TROUGH...THE MOST IMPORTANT FEATURE IN THE SHORT TERM IS A SHRTWV CROSSING NE WI. 12Z INL SOUNDING...WHICH WAS SITUATED SOMEWHAT CLOSE TO THE SHRTWV BACK AT 12Z...SHOWED A NEARLY SATURATED PROFILE FROM THE SFC TO 600MB... ALONG WITH TEMPS MOSTLY BELOW -10C THROUGH THIS LAYER. THIS COLD AIR CROSSING LAKE SUPERIOR CONTINUES TO GENERATE LAKE EFFECT SNOW SHOWERS...ESPECIALLY GIVEN THAT LAKE SURFACE TEMPERATURES ARE RUNNING 5-6C. BANDS WERE ORGANIZED THIS MORNING...PARTICULARLY OVER ERN MARQUETTE AND WRN ALGER COUNTIES WHERE OVER THE HIGHER TERRAIN SNOWFALL RATES WERE 1-1.5 INCHES PER HOUR. LOCATIONS NEAR THE SHORELINE WERE RUNNING A LITTLE LESS THAN THAT...DUE TO PROXIMITY OF THE WARMER LAKE PRODUCING MORE SMALLER SNOWFLAKES COMPARED TO THE DENDRITES OVER THE HIGHER TERRAIN. HOWEVER...DAYTIME HEATING DISRUPTED THE BANDS FOR EARLY THIS AFTERNOON. NOW THAT THE SUN IS SETTING...VISIBLE SATELLITE IMAGERY IS STARTING TO INDICATE A SINGLE BAND FORMING FROM LAKE NIPIGON...THROUGH CENTRAL LAKE SUPERIOR...TO MARQUETTE AND INTO NW LOWER MI. THIS IS DUE TO A NNE FLOW ON EASTERN LAKE SUPERIOR IMPINGING ON NW FLOW ACROSS THE WESTERN HALF OF THE CWA. TO THE WEST...1037MB HIGH PRESSURE CAN BE SEEN OVER THE PLAINS. DRIER AIR FROM THIS HIGH IS GRADUALLY MAKING IN ROADS INTO THE WESTERN CWA...NOTED BY DEWPOINTS AROUND 10F AT CMX AND IWD. THIS DRIER AIR HAS KEPT THE LAKE EFFECT FROM BEING AS HEAVY OVER WESTERN UPPER MI. LAST ITEM TO NOTE IS A SHRTWV COMING INTO THE NW BRITISH COLUMBIA COAST...WHICH IS THE NEXT SYSTEM TO AFFECT THE CWA. SNOWFALL AMOUNT WISE...LOCATIONS OVER THE HIGHER TERRAIN OF WESTERN ALGER COUNTY HAVE ALREADY SEEN OVER A FOOT SINCE LAST EVENING...WITH A REPORT FROM TRENARY AROUND 19 INCHES. MORE REPORTS CAN BE SEEN ON THE LATEST ARBLSRMQT. && .SHORT TERM (TONIGHT AND TUESDAY)... ISSUED AT 432 PM EST AS THE NW BRITISH COLUMBIA SHRTWV MOVES EAST OVER THE NEXT 24 HOURS...IT WILL PUSH THE SW CANADA RIDGE TOWARDS THE GREAT LAKES...MORE FLATTENING IT OUT WITH TIME. THIS MEANS MUCH OF THE WARM AIR ASSOCIATED WITH THE RIDGE IS EXPECTED TO STAY AWAY FROM HERE. HOWEVER...THE PROGRESSION OF THE RIDGE WILL ALLOW THE AREA OF HIGH PRESSURE OVER THE PLAINS TO CROSS UPPER MICHIGAN DURING THE DAY TUESDAY...ALLOWING LAKE EFFECT TO END WEST TO EAST. UNTIL THEN... TONIGHT APPEARS NOW OF MOSTLY MULTI-PARALLEL BANDS COMING OFF LAKE SUPERIOR...DUE TO SUBSIDENCE IN THE WAKE OF THE NE WI SHRTWV AND MOSTLY UNIDIRECTIONAL NORTH FLOW. IT IS POSSIBLE THAT SOME OF THE BANDS COULD BECOME STATIONARY...WHICH MEANS UPSLOPE AREAS SUCH AS IN MARQUETTE AND ALGER COUNTIES WITH THE LONGER FETCH OFF LAKE SUPERIOR COULD END UP WITH 5 INCHES OF 20-25 TO 1 SNOW. IN ADDITION...SINCE WE ARE GOING INTO THE DIURNAL MINIMUM WHEN LAND BREEZES ARE FAVORED...A STRONGER SINGLE BAND IS NOT OUT OF THE QUESTION. THEREFORE...AT LEAST THE WARNINGS FOR MQT..ALGER AND NRN SCHOOLCRAFT COUNTIES SEEM REASONABLE. FOR WESTERN UPPER MI...DRIER AIR SHOULD KEEP THE LAKE EFFECT TO A MINIMUM...THOUGH EXTRA CONVERGENCE IN THE GOGEBIC/ONTONAGON COUNTY AREA EXPECTED THIS EVENING MAY ALLOW FOR A LITTLE EXTRA SNOW AND THEREFORE EXTENDED THE ADVISORY. GOING LOW TEMPERATURES LOOKED REASONABLE. FOR TUESDAY...AGAIN LAKE EFFECT SNOW EXPECTED TO DIMINISH WEST TO EAST AS INVERSIONS LOWER...WINDS BACK AND DRIER AIR MOVES IN WITH THE HIGH PRESSURE AREA. IN FACT...MUCH OF THE WEST HALF OF THE CWA SHOULD BE DRY FOR THE AFTERNOON. WITH GRADUAL WARMING OF 850MB TEMPS...FROM AROUND -14C NOW TO -12C TUE AFTN...TOMORROW SHOULD END UP SLIGHTLY WARMER THAN TODAY. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... SFC RDG AXIS WL BE OVER THE ERN U.P. AT 00Z TUE...BUT WAD CLD WL BE SPILLING IN FM THE W AHEAD OF NEXT SHRTWV SPILLING OVER THE RDG IN THE PLAINS. ALTHOUGH THE LLVLS WL BE INITIALLY DRY...THE ISENTROPIC LIFT SHOWN ON THE 280-295K SFCS/H85-5 QVECTOR CNVGC APPEARS SUFFICIENTLY STRONG TO GENERATE PCPN...ESPECIALLY OVER THE NE HALF OF THE FA WHERE PARCELS WL HAVE A LONGER PD OF UPGLIDE TO SATURATE AND WHERE FLOW OFF LK MI WL ACCENTUATE MOISTENING ACRS THE ERN ZNS. GFS MOS GUIDANCE SEEMS TO HAVE THE BEST HANDLE ON POPS. IN FACT... NAM/GFS QPF IS QUITE A BIT HIER OVER THE FAR ERN ZNS WHERE THERE IS LIKELY TO BE SOME LK ENHANCEMENT OF THE SHSN (H85 TEMPS FCST ARND -9C VS WATER TEMP ARND 8C) AFT 06Z IN SSW FLOW OVER THE LENGTH OF LK MI. NAM/GFS FCST SDNGS FOR ERY ALSO SHOW AN ALMOST 10K FT DEPTH OF LYR WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH IN THE 06Z-12Z TIME FRAME. ELECTED TO BUMP UP POP TO HI CHC/LIKELY IN THIS AREA ABV MOS GUIDANCE. CLIPPER LO PROGGED TO SHIFT INTO ERN LK SUP BY 00Z THU. POTENTIAL FOR LK ENHANCED SHSN WL LINGER ON WED MRNG OVER THE FAR E...BUT VEERING FLOW TO W LATER IN THE DAY WL END THE THREAT. LATER SHIFTS MAY NEED TO CONSIDER AN ADVY FOR PORTIONS OF THE ERN ZNS BEFORE THE LK ENHANCED SN DIMINISHES THERE. WL INCLUDE MENTION IN HWO. OTRW... THREAT FOR LARGER SCALE PCPN WL END W-E WL LOSS OF ISENTROPIC LIFT AND MID LVL DRY SURGE UNDER UPR JET AXIS THAT WL CUT OFF LLVL MSTR FM DENDRITIC SN GROWTH LYR. OTRW...ARRIVAL OF CYC NW FLOW LATE IN THE DAY WL CAUSE SOME LES TO DVLP OVER THE W...BUT AIRMASS DOES NOT APPEAR SUFFICIENTLY COLD UNTIL LATE FOR SGNFT LES (H85 TEMP ARND -6C OVER WRN LK SUP AT 18Z FALLS TO -10C AT 00Z THU) WITH RELATIVELY SHALLOW MSTR BLO DGZ. EXPECT INCRSG LES ON WED NGT/THU WITH STRENGTHENING NNW FLOW BTWN DEPARTING CLIPPER LO AND ARCTIC HI PRES BLDG INTO SCNTRL CAN DRIVING H85 TEMPS AS LO AS -17C OVER LK SUP BY 00Z FRI. MODELS SHOW H925 WINDS BTWN 330-350 OR SO AND UP TO 30 KTS...WL HIT THE POPS UP HIEST IN THOSE AREAS FVRD BY THAT WIND DIRECTION. AT SOME POINT...A HEADLINE FOR LES WL LIKELY BE NECESSARY IN THESE FVRD AREAS WITH FCST SDNGS SHOWING CONSIDERABLE OMEGA WITHIN THE DGZ. WL MENTION IN THE HWO FOR NOW. WITH FALLING H85 TEMPS ON THU...EXPECT LTL DIURNAL RECOVERY IN TEMP. ONGOING LES/GUSTY WINDS ON THU NGT WL BEGIN TO DIMINISH W-E ON FRI WITH APRCH OF SFC RDG AXIS. PER NCEP GUIDANCE...TENDED TO FOLLOW THE QUICKER 00Z ECMWF/CNDN MODELS AND 12Z ECMWF FOR TIMING ARRIVAL OF RDG AXIS FM THE W AND ENDING OF THE LES. AS NEXT CLIPPER SHRTWV APRCHS FM THE W ON FRI NGT/SAT/SAT NGT...A STRONG WAD PATTERN WL SET UP ACRS THE UPR LKS TO THE NW OF DEPARTING SFC RDG AXIS. WL CARRY CHC POPS FOR -SN...WITH THE HIER POPS OVER NRN LK SUP/THE ERN FA CLOSER TO TRACK OF SFC LO PROGGED ACRS SRN ONTARIO AND WHERE THERE MAY BE SOME MOISTENING OFF LK MI. ANY SYNOPTIC SCALE SN WL END ON SUN WITH PASSAGE OF CLIPPER AND TRANSITION TO LES INTO MON WITH COLD AIR INFUSION (00Z ECMWF SHOWS H85 TEMP FALLING TO ARND -15C BY 12Z MON) IN THE WAKE OF CLIPPER LO. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KCMX...EXPECT VARYING CONDITIONS DURING THE EVENING AS INTERMITTENT -SHSN PASS OVER THE AREA. DUE TO SHADOWING FROM ISLE ROYALE UNDER NNW WINDS...LAKE EFFECT -SHSN SHOULD BE FAIRLY LIGHT. EXPECT PREVAILING CONDITIONS TO BE VFR WITH OCCASIONAL MVFR THOUGH IT`S CERTAINLY NOT OUT OF THE QUESTION THAT BRIEF IFR VIS COULD STILL OCCUR AT TIMES. VFR CONDITIONS SHOULD BE THE RULE OVERNIGHT WITH CIGS FALLING TO MVFR LATE IN THE NIGHT THRU TUE MORNING AS SUBSIDENCE INVERSION LOWERS. AS WINDS BACK SW LATE TUE AFTN...VFR CONDITIONS WILL DEVELOP. AT KSAW...UNDER NRLY WINDS...EXPECT WIDE SWINGS IN CONDITIONS AS LONG FETCH ACROSS THE LAKE AND UPSLOPING RESULT IN HEAVIER SNOW SHOWERS AT TIMES. WHILE PREVAILING CONDITIONS SHOULD BE MVFR... HEAVIER SNOW SHOWERS WILL LIKELY RESULT IN PERIODIC IFR/LIFR CONDITIONS INTO THE OVERNIGHT. LATE IN THE NIGHT...LOWERING SUBSIDENCE INVERSION WILL LEAD TO DIMINISHING -SHSN WITH MVFR CONDITIONS BECOMING THE RULE. FURTHER IMPROVEMENT TO VFR EXPECTED EARLY TUE AFTN AS WINDS BACK W THEN SW. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... NORTH WINDS OF UP TO 30 KNOTS WILL DIMINISH TONIGHT INTO TUE MORNING AS A RIDGE OF HIGH PRESSURE CROSSES LAKE SUPERIOR. HOWEVER...ANOTHER LOW PRESSURE AREA REACHING NORTH DAKOTA TUESDAY EVENING IS EXPECTED TO CROSS JUST NORTH OF LAKE SUPERIOR ON WEDNESDAY...AND THEN MOVE TO THE LOWER GREAT LAKES BY THURSDAY. IN ITS WAKE FOR THURSDAY...A PERIOD OF NORTHERLY GALES TO 35 KNOTS IS POSSIBLE ON THURSDAY AS COLD AIR FLOWS SOUTH. FOR THURSDAY NIGHT INTO SATURDAY...ANOTHER RIDGE OF HIGH PRESSURE OVER THE PLAINS WILL BUILD BACK INTO UPPER MICHIGAN...BRINGING WINDS BACK DOWN BELOW GALES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ005-006-085. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ013. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM DISCUSSION...AJ LONG TERM DISCUSSION...KC AVIATION...ROLFSON MARINE...AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 432 PM EST MON NOV 17 2008 .SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC ANALYSIS SHOWED A POSITIVE PNA PATTERN WITH STRONG RIDGING ACROSS THE WESTERN U.S. INTO SW CANADA AND TROUGHING ACROSS EASTERN CANADA INTO THE GREAT LAKES. BETWEEN THE TROUGH AND RIDGE...A 120-140 KT JET AROUND 200MB EXTENDS FROM NORTHERN SASKATCHEWAN INTO SW MN. WITHIN THE UPPER TROUGH...THE MOST IMPORTANT FEATURE IN THE SHORT TERM IS A SHRTWV CROSSING NE WI. 12Z INL SOUNDING...WHICH WAS SITUATED SOMEWHAT CLOSE TO THE SHRTWV BACK AT 12Z...SHOWED A NEARLY SATURATED PROFILE FROM THE SFC TO 600MB... ALONG WITH TEMPS MOSTLY BELOW -10C THROUGH THIS LAYER. THIS COLD AIR CROSSING LAKE SUPERIOR CONTINUES TO GENERATE LAKE EFFECT SNOW SHOWERS...ESPECIALLY GIVEN THAT LAKE SURFACE TEMPERATURES ARE RUNNING 5-6C. BANDS WERE ORGANIZED THIS MORNING...PARTICULARLY OVER ERN MARQUETTE AND WRN ALGER COUNTIES WHERE OVER THE HIGHER TERRAIN SNOWFALL RATES WERE 1-1.5 INCHES PER HOUR. LOCATIONS NEAR THE SHORELINE WERE RUNNING A LITTLE LESS THAN THAT...DUE TO PROXIMITY OF THE WARMER LAKE PRODUCING MORE SMALLER SNOWFLAKES COMPARED TO THE DENDRITES OVER THE HIGHER TERRAIN. HOWEVER...DAYTIME HEATING DISRUPTED THE BANDS FOR EARLY THIS AFTERNOON. NOW THAT THE SUN IS SETTING...VISIBLE SATELLITE IMAGERY IS STARTING TO INDICATE A SINGLE BAND FORMING FROM LAKE NIPIGON...THROUGH CENTRAL LAKE SUPERIOR...TO MARQUETTE AND INTO NW LOWER MI. THIS IS DUE TO A NNE FLOW ON EASTERN LAKE SUPERIOR IMPINGING ON NW FLOW ACROSS THE WESTERN HALF OF THE CWA. TO THE WEST...1037MB HIGH PRESSURE CAN BE SEEN OVER THE PLAINS. DRIER AIR FROM THIS HIGH IS GRADUALLY MAKING IN ROADS INTO THE WESTERN CWA...NOTED BY DEWPOINTS AROUND 10F AT CMX AND IWD. THIS DRIER AIR HAS KEPT THE LAKE EFFECT FROM BEING AS HEAVY OVER WESTERN UPPER MI. LAST ITEM TO NOTE IS A SHRTWV COMING INTO THE NW BRITISH COLUMBIA COAST...WHICH IS THE NEXT SYSTEM TO AFFECT THE CWA. SNOWFALL AMOUNT WISE...LOCATIONS OVER THE HIGHER TERRAIN OF WESTERN ALGER COUNTY HAVE ALREADY SEEN OVER A FOOT SINCE LAST EVENING...WITH A REPORT FROM TRENARY AROUND 19 INCHES. MORE REPORTS CAN BE SEEN ON THE LATEST ARBLSRMQT. && .SHORT TERM (TONIGHT AND TUESDAY)... AS THE NW BRITISH COLUMBIA SHRTWV MOVES EAST OVER THE NEXT 24 HOURS...IT WILL PUSH THE SW CANADA RIDGE TOWARDS THE GREAT LAKES...MORE FLATTENING IT OUT WITH TIME. THIS MEANS MUCH OF THE WARM AIR ASSOCIATED WITH THE RIDGE IS EXPECTED TO STAY AWAY FROM HERE. HOWEVER...THE PROGRESSION OF THE RIDGE WILL ALLOW THE AREA OF HIGH PRESSURE OVER THE PLAINS TO CROSS UPPER MICHIGAN DURING THE DAY TUESDAY...ALLOWING LAKE EFFECT TO END WEST TO EAST. UNTIL THEN... TONIGHT APPEARS NOW OF MOSTLY MULTI-PARALLEL BANDS COMING OFF LAKE SUPERIOR...DUE TO SUBSIDENCE IN THE WAKE OF THE NE WI SHRTWV AND MOSTLY UNIDIRECTIONAL NORTH FLOW. IT IS POSSIBLE THAT SOME OF THE BANDS COULD BECOME STATIONARY...WHICH MEANS UPSLOPE AREAS SUCH AS IN MARQUETTE AND ALGER COUNTIES WITH THE LONGER FETCH OFF LAKE SUPERIOR COULD END UP WITH 5 INCHES OF 20-25 TO 1 SNOW. IN ADDITION...SINCE WE ARE GOING INTO THE DIURNAL MINIMUM WHEN LAND BREEZES ARE FAVORED...A STRONGER SINGLE BAND IS NOT OUT OF THE QUESTION. THEREFORE...AT LEAST THE WARNINGS FOR MQT..ALGER AND NRN SCHOOLCRAFT COUNTIES SEEM REASONABLE. FOR WESTERN UPPER MI...DRIER AIR SHOULD KEEP THE LAKE EFFECT TO A MINIMUM...THOUGH EXTRA CONVERGENCE IN THE GOGEBIC/ONTONAGON COUNTY AREA EXPECTED THIS EVENING MAY ALLOW FOR A LITTLE EXTRA SNOW AND THEREFORE EXTENDED THE ADVISORY. GOING LOW TEMPERATURES LOOKED REASONABLE. FOR TUESDAY...AGAIN LAKE EFFECT SNOW EXPECTED TO DIMINISH WEST TO EAST AS INVERSIONS LOWER...WINDS BACK AND DRIER AIR MOVES IN WITH THE HIGH PRESSURE AREA. IN FACT...MUCH OF THE WEST HALF OF THE CWA SHOULD BE DRY FOR THE AFTERNOON. WITH GRADUAL WARMING OF 850MB TEMPS...FROM AROUND -14C NOW TO -12C TUE AFTN...TOMORROW SHOULD END UP SLIGHTLY WARMER THAN TODAY. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... SFC RDG AXIS WL BE OVER THE ERN U.P. AT 00Z TUE...BUT WAD CLD WL BE SPILLING IN FM THE W AHEAD OF NEXT SHRTWV SPILLING OVER THE RDG IN THE PLAINS. ALTHOUGH THE LLVLS WL BE INITIALLY DRY...THE ISENTROPIC LIFT SHOWN ON THE 280-295K SFCS/H85-5 QVECTOR CNVGC APPEARS SUFFICIENTLY STRONG TO GENERATE PCPN...ESPECIALLY OVER THE NE HALF OF THE FA WHERE PARCELS WL HAVE A LONGER PD OF UPGLIDE TO SATURATE AND WHERE FLOW OFF LK MI WL ACCENTUATE MOISTENING ACRS THE ERN ZNS. GFS MOS GUIDANCE SEEMS TO HAVE THE BEST HANDLE ON POPS. IN FACT... NAM/GFS QPF IS QUITE A BIT HIER OVER THE FAR ERN ZNS WHERE THERE IS LIKELY TO BE SOME LK ENHANCEMENT OF THE SHSN (H85 TEMPS FCST ARND -9C VS WATER TEMP ARND 8C) AFT 06Z IN SSW FLOW OVER THE LENGTH OF LK MI. NAM/GFS FCST SDNGS FOR ERY ALSO SHOW AN ALMOST 10K FT DEPTH OF LYR WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH IN THE 06Z-12Z TIME FRAME. ELECTED TO BUMP UP POP TO HI CHC/LIKELY IN THIS AREA ABV MOS GUIDANCE. CLIPPER LO PROGGED TO SHIFT INTO ERN LK SUP BY 00Z THU. POTENTIAL FOR LK ENHANCED SHSN WL LINGER ON WED MRNG OVER THE FAR E...BUT VEERING FLOW TO W LATER IN THE DAY WL END THE THREAT. LATER SHIFTS MAY NEED TO CONSIDER AN ADVY FOR PORTIONS OF THE ERN ZNS BEFORE THE LK ENHANCED SN DIMINISHES THERE. WL INCLUDE MENTION IN HWO. OTRW... THREAT FOR LARGER SCALE PCPN WL END W-E WL LOSS OF ISENTROPIC LIFT AND MID LVL DRY SURGE UNDER UPR JET AXIS THAT WL CUT OFF LLVL MSTR FM DENDRITIC SN GROWTH LYR. OTRW...ARRIVAL OF CYC NW FLOW LATE IN THE DAY WL CAUSE SOME LES TO DVLP OVER THE W...BUT AIRMASS DOES NOT APPEAR SUFFICIENTLY COLD UNTIL LATE FOR SGNFT LES (H85 TEMP ARND -6C OVER WRN LK SUP AT 18Z FALLS TO -10C AT 00Z THU) WITH RELATIVELY SHALLOW MSTR BLO DGZ. EXPECT INCRSG LES ON WED NGT/THU WITH STRENGTHENING NNW FLOW BTWN DEPARTING CLIPPER LO AND ARCTIC HI PRES BLDG INTO SCNTRL CAN DRIVING H85 TEMPS AS LO AS -17C OVER LK SUP BY 00Z FRI. MODELS SHOW H925 WINDS BTWN 330-350 OR SO AND UP TO 30 KTS...WL HIT THE POPS UP HIEST IN THOSE AREAS FVRD BY THAT WIND DIRECTION. AT SOME POINT...A HEADLINE FOR LES WL LIKELY BE NECESSARY IN THESE FVRD AREAS WITH FCST SDNGS SHOWING CONSIDERABLE OMEGA WITHIN THE DGZ. WL MENTION IN THE HWO FOR NOW. WITH FALLING H85 TEMPS ON THU...EXPECT LTL DIURNAL RECOVERY IN TEMP. ONGOING LES/GUSTY WINDS ON THU NGT WL BEGIN TO DIMINISH W-E ON FRI WITH APRCH OF SFC RDG AXIS. PER NCEP GUIDANCE...TENDED TO FOLLOW THE QUICKER 00Z ECMWF/CNDN MODELS AND 12Z ECMWF FOR TIMING ARRIVAL OF RDG AXIS FM THE W AND ENDING OF THE LES. AS NEXT CLIPPER SHRTWV APRCHS FM THE W ON FRI NGT/SAT/SAT NGT...A STRONG WAD PATTERN WL SET UP ACRS THE UPR LKS TO THE NW OF DEPARTING SFC RDG AXIS. WL CARRY CHC POPS FOR -SN...WITH THE HIER POPS OVER NRN LK SUP/THE ERN FA CLOSER TO TRACK OF SFC LO PROGGED ACRS SRN ONTARIO AND WHERE THERE MAY BE SOME MOISTENING OFF LK MI. ANY SYNOPTIC SCALE SN WL END ON SUN WITH PASSAGE OF CLIPPER AND TRANSITION TO LES INTO MON WITH COLD AIR INFUSION (00Z ECMWF SHOWS H85 TEMP FALLING TO ARND -15C BY 12Z MON) IN THE WAKE OF CLIPPER LO. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... 21Z...UPDATED CMX LAKE EFFECT SNOW SHOWERS CONTINUE TO BE THE MAIN CONCERN FOR BOTH TAF SITES FOR THE NEXT 24 HOURS. AT CMX...CONDITIONS HAVE IMPROVED GREATLY FROM A FEW HOURS AGO...WITH VSBYS AND CIGS BOTH VFR. IT IS POSSIBLE NOW...THAT AT LEAST THROUGH MUCH OF THE NIGHT UNTIL WINDS GO MORE NW...THAT VSBYS AND CIGS STAY VFR. THIS IS DUE TO BLOCKING OF THE LAKE EFFECT OFF ISLE ROYALE. IF THE TREND CONTINUES...ADDITIONAL IMPROVEMENT IN THE TAF WILL BE NEEDED FOR THE 00Z TAF ISSUANCE. LAKE EFFECT CLOUDS ARE EXPECTED TO HANG IN THROUGH TOMORROW MORNING...THOUGH. AT SAW...WINDS FROM THE NORTH TO NE ON EASTERN LAKE SUPERIOR WILL HELP MAINTAIN SNOW SHOWERS THROUGH TONIGHT. SNOW SHOWERS SHOULD BE MOST INTENSE THIS AFTERNOON AND EARLY EVENING...DUE TO CONVERGENCE OF THE WINDS NEAR SAW AND AN UPPER LEVEL DISTURBANCE MOVING THROUGH. VIS EXPECTED TO FLUCTUATE BTWN IFR AND VLIFR WITH CIGS BTWN MVFR AND LIFR. CONDITIONS WILL GRADUALLY IMPROVE LATE THIS EVENING AND INTO THE OVERNIGHT HOURS TONIGHT AS WINDS BEGIN TO BACK...ALLOWING DRIER AIR TO MOVE IN. BY LATE TOMORROW MORNING...ENOUGH DRYING AND BACKING OF THE WINDS SHOULD OCCUR TO BRING VIS UP TO VFR AND CIGS TO MVFR. CLOUDS ARE EXPECTED TO BREAK UP ENOUGH TO GO VFR AFTER THE END OF THE FORECAST PERIOD. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... NORTH WINDS OF UP TO 30 KNOTS WILL DIMINISH TONIGHT INTO TUE MORNING AS A RIDGE OF HIGH PRESSURE CROSSES LAKE SUPERIOR. HOWEVER...ANOTHER LOW PRESSURE AREA REACHING NORTH DAKOTA TUESDAY EVENING IS EXPECTED TO CROSS JUST NORTH OF LAKE SUPERIOR ON WEDNESDAY...AND THEN MOVE TO THE LOWER GREAT LAKES BY THURSDAY. IN ITS WAKE FOR THURSDAY...A PERIOD OF NORTHERLY GALES TO 35 KNOTS IS POSSIBLE ON THURSDAY AS COLD AIR FLOWS SOUTH. FOR THURSDAY NIGHT INTO SATURDAY...ANOTHER RIDGE OF HIGH PRESSURE OVER THE PLAINS WILL BUILD BACK INTO UPPER MICHIGAN...BRINGING WINDS BACK DOWN BELOW GALES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ005-006-085. LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY FOR MIZ002-009. LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ013. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM DISCUSSION...AJ LONG TERM DISCUSSION...KC AVIATION...AJ MARINE...AJ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 103 PM EST MON NOV 17 2008 .UPDATE... 17Z WATER VAPOR LOOP AND RUC ANALYSIS SHOWED A SHRTWV CROSSING WESTERN LAKE SUPERIOR DIVING SE THROUGH A BROAD TROUGH OVER THE GREAT LAKES. NO GOOD 12Z RAOB SOUNDING LOCATED UNDER THE SHRTWV...HOWEVER THE ONE FROM INL WHICH WAS CLOSE TO THE SHRTWV SHOWED A NEARLY SATURATED PROFILE FROM THE SFC TO 600MB...ALONG WITH TEMPS MOSTLY BELOW -10C THROUGH THIS LAYER. THIS COLD AIR CROSSING SUPERIOR CONTINUES TO GENERATE LAKE EFFECT SNOW SHOWERS. ORIENTATION OF THE BANDS HAS BEEN A BIT PUZZLING THIS MORNING...PARTICULARLY HERE IN THE PAST HOUR AS WHAT IT APPEARS TO BE AN EAST-WEST BAND DROPPING SOUTH. BEST GUESS PER SFC ANALYSIS IS THAT THE BAND IS THE TYPICAL LAKE-INDUCED SFC TROUGH THAT IS BEING PUSHED SOUTHWARD BY THE SHRTWV. OUTSIDE OF THE TROUGH...LAKE EFFECT STILL REMAINS SOMEWHAT DISORGANIZED DUE TO THE NORMAL DAYTIME HEATING DISRUPTING BANDS...BUT IN THE MEAN THERE ARE PERSISTENT SNOW SHOWERS OVER FAR ERN MARQUETTE COUNTY/WRN ALGER COUNTY...NRN DELTA COUNTY...AND SCATTERED ABOUT OVER THE WRN UPPER PENINSULA. LOOKS LIKE THE ISSUE OF THE WIND DIRECTION IS FINALLY BEEN FIGURED OUT...WITH OBS OVER CENTRAL AND EASTERN LAKE SUPERIOR TURNING NE. THE ISSUE WAS RELATED TO MODEL HANDLING OF THE SHRTWV...WHERE THE MORE NW WIND OF THE GFS WAS DUE TO ITS MUCH FASTER PROGRESSION OF THE SHRTWV. OTHER MODELS...IN PARTICULAR THE NAM/LOCAL WRF-ARW/RUC 13 WERE SLOWER WITH THE SHRTWV AND THEREFORE ALLOWING MORE NE WIND TO DEVELOP. UPDATED FORECAST BACK AT 10 AM HEDGED TOWARD THE MORE NE IDEA...WHICH STILL FAVORS THE ERN PORTION OF MARQUETTE COUNTY AND WRN ALGER COUNTY. THIS AREA HAS ALREADY RECEIVED 1-1.5 INCH PER HOUR RATES. SEE LOCAL STORM REPORTS FOR MORE INFORMATION. IN ADDITION...ALL MESOSCALE MODELS INSIST ON A BAND OVER WRN ALGER COUNTY BEING PUSHED INTO MARQUETTE COUNTY SOMEWHERE AROUND 21 OR 22Z...WITH A LOT OF LIFT. THIS SEEMS REASONABLE BASED ON LATEST VISIBLE IMAGERY AND THAT AFTER THE SHRTWV PASSES...THE BAND WOULD HAVE TO MIGRATE WESTWARD...THEN GET ENHANCED BY THE HIGHER TERRAIN. WSW STATEMENT INCLUDES POTENTIAL FOR WHITEOUT CONDITIONS WITH THIS BAND. OVERALL TO THE FORECAST...NO MAJOR CHANGES WERE NEEDED. && .DISCUSSION (ISSUED AT 523 AM EST)... UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH ACROSS EASTERN N.A. WITH A RIDGE ACROSS WESTERN N.A. THERE IS A SHORTWAVE EAST OF LAKE WINNIPEG AND THIS SHORTWAVE WILL BE THE WEATHER MAKER HERE FOR TODAY AND ALSO INTO TONIGHT AS IT WILL AID IN LAKE EFFECT SNOW PRODUCTION WITH SOME COLDER AIR MOVING ACROSS LAKE SUPERIOR AND RAISING INVERSION HEIGHTS. NAM SHOWING SOME 850-500 MB Q-VECTOR CONVERGENCE MOVING THROUGH THE CWA TODAY WITH THAT SHORTWAVE AND DEEP MOISTURE WHICH MOVES OUT TONIGHT. GFS SHOWS THE SAME THING. NAM/GFS SHOW SOME 850-500 MB Q-VECTOR CONVERGENCE RETURNING 06Z WED AND THIS LASTS THROUGH 00Z THU BEFORE THE CONVERGENCE MOVES OUT. THIS FORECAST WAS VERY DIFFICULT TODAY BASED ON MESOSCALE EFFECTS WITH MODELS THAT DO NOT HANDLE THE MESOSCALE WELL AT ALL. PROBLEM CONTINUES TO BE THE DIFFERENCE IN MODELS WITH REGARD TO WIND DIRECTION. NORMALLY...THIS WOULD NOT BE A BIG DEAL...EXCEPT WHEN IT COMES TO LAKE EFFECT. THE GFS IS SHOWING A NNW WIND WHICH IT HAS BEEN CONSISTENT DOING. CANADIAN IS NORTHERLY AND A COMPROMISE. THE RUC/NAM/HI RES WRF SHOW A NNE WIND AND THEY HAVE CONSISTENTLY BEEN SHOWING THAT AS WELL. SO FAR...THE COMPROMISE CANADIAN SEEMS TO BE DOING BETTER ON THE WIND DIRECTION ANYWAY. WIND DIRECTION WILL MAKE A DIFFERENCE IN WHERE THE HEAVY SNOW FALLS AND HAD A TOUGH TIME FIGURING THIS OUT. WENT WITH A COMPROMISE NORTH WIND DIRECTION AND THIS LASTS LONG ENOUGH TO CAUSE A FEW CHANGES TO HEADLINES. WITH A NORTH WIND...THE EAST HALF OF MARQUETTE COUNTY WILL GET HIT WITH A HEAVY LAKE EFFECT SNOW BAND AND UPGRADED TO A LAKE EFFECT WARNING THERE WITH NEARLY A FOOT OR MORE EAST OF A LINE FROM ISHPEMING TO MCFARLAND EXPECTED TODAY. WITH THE BAND ACROSS ERN MARQUETTE AND WESTERN ALGER COUNTIES...THIS WILL AFFECT NORTHERN DELTA COUNTY AND SOUTHERN SCHOOLCRAFT COUNTIES AS WELL AND HAD TO PUT THEM IN ADVISORIES FOR THE HEAVIER SNOW BAND. ADDED THE KEWEENAW AS WELL FOR HEAVIER SNOW TODAY WITH ADVISORY LOOKING GOOD THERE AND ONTONAGON AND GOGEBIC ADVISORIES LOOK GOOD AS WELL TODAY. INVERSION HEIGHTS START FALLING TONIGHT...SO HEAVY SNOW OVER THE WEST WILL TAPER OFF FIRST AND NO ADVISORIES NEEDED. OVER THE EAST...HEAVY SNOW WILL TAPER OFF AS WELL AS INVERSION HEIGHTS FALL AFTER MIDNIGHT AND BAND SHIFTS EAST OF MARQUETTE. WILL PROBABLY HAVE TO HAVE HEADLINES CONTINUE THROUGH TONIGHT EAST OF MARQUETTE AND THIS WILL BE DEPENDENT ON WHEN WINDS SWITCH BACK TO THE NW AND WITH MODELS UP IN THE AIR ON THIS FOR TIMING...DID NOT CHANGE TIMING FOR NOW. WITH NEWER GUIDANCE COMING IN...THIS SHOULD BECOME CLEARER. RIDGING BUILDS IN FOR TUE...SO LAKE EFFECT CONTINUES TO WIND DOWN. ONE THING TO WATCH THOUGH WOULD BE A POSSIBLE LAKE MICHIGAN LAKE EFFECT SNOW EVENT FOR TUE NIGHT AS WINDS GO TO THE SOUTH. IT WILL STILL BE COLD ENOUGH AT 850 MB FOR ENOUGH DELTA-T TO FORM LAKE MICHIGAN LAKE EFFECT SNOW SHOWERS AND PUT IN SLIGHT CHANCE RIGHT NOW FOR THIS POSSIBILITY. NEXT SYSTEM WILL BE A CLIPPER FOR TUE NIGHT AND WED. BUMPED POPS UP TO LIKELY ACROSS THE EAST WITH THE CLIPPER AS MOISTURE SEEMS TO BE ABUNDANT ALONG WITH DYNAMICS ALONG WITH SOME LAKE ENHANCEMENT. INTERESTING THING ABOUT THE NEXT LAKE EFFECT EVENT FOR WED NIGHT AND THU. BASED ON NAM/GFS SOUNDINGS FOR CMX...IWD...ERY AND SAW...COULD HAVE ANOTHER EVENT LIKE WHAT WE JUST HAD WHERE THE LIFT AND MOISTURE STAY BELOW THE DENDRITIC GROWTH ZONE AS THESE SOUNDINGS ARE INDICATING. THIS WOULD CUT DOWN ON IDEAL SNOW GROWTH AND CUT AMOUNTS DOWN FROM WHAT WOULD NORMALLY BE A GOOD SNOWFALL AMOUNT. THIS WILL NEED TO BE WATCHED TO SEE IF THIS TREND CONTINUES AND SEE IF THE LIFT AND MOISTURE STAY BELOW THE IDEAL TEMPERATURES FOR IDEAL SNOW GROWTH. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... LAKE EFFECT SNOW SHOWERS CONTINUE TO BE THE MAIN CONCERN FOR BOTH TAF SITES FOR THE NEXT 24 HOURS. AT CMX...CONDITIONS SHOULD CONTINUE TO FLUCTUATE BETWEEN IFR AND LIFR ON VIS AND MVFR/IFR ON CIGS FOR THE REST OF THE AFTN...DUE TO NW WINDS AND ENHANCEMENT FROM AN UPPER LEVEL DISTURBANCE. TONIGHT...DRIER AIR WORKING IN WILL HELP TO IMPROVE VIS AND CIGS INTO THE MVFR RANGE BY MIDNIGHT...AND THEN TO VFR ON THE VIS AND MVFR ON THE CIG BY SUNRISE. LAKE EFFECT CLOUDS LOOK TO STAY AROUND THROUGH 18Z TOMORROW...THOUGH. AT SAW...WINDS FROM THE NORTH TO NE ON EASTERN LAKE SUPERIOR WILL HELP MAINTAIN SNOW SHOWERS THROUGH TONIGHT. SNOW SHOWERS SHOULD BE MOST INTENSE THIS AFTERNOON AND EARLY EVENING...DUE TO CONVERGENCE OF THE WINDS NEAR SAW AND AN UPPER LEVEL DISTURBANCE MOVING THROUGH. VIS EXPECTED TO FLUCTUATE BTWN IFR AND VLIFR WITH CIGS BTWN MVFR AND LIFR. CONDITIONS WILL GRADUALLY IMPROVE LATE THIS EVENING AND INTO THE OVERNIGHT HOURS TONIGHT AS WINDS BEGIN TO BACK...ALLOWING DRIER AIR TO MOVE IN. BY LATE TOMORROW MORNING...ENOUGH DRYING AND BACKING OF THE WINDS SHOULD OCCUR TO BRING VIS UP TO VFR AND CIGS TO MVFR. CLOUDS ARE EXPECTED TO BREAK UP ENOUGH TO GO VFR AFTER THE END OF THE FORECAST PERIOD. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT SLOWLY DIMINISHING WINDS AS HIGH PRESSURE OVER SOUTHEASTERN SASKATCHEWAN WILL DIVE SOUTHEASTWARD TO IOWA AND MISSOURI BY TUESDAY MORNING...WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS LAKE SUPERIOR DURING THE DAY TUESDAY. LOW PRESSURE OVER NORTH DAKOTA TUESDAY EVENING IS EXPECTED TO CROSS LAKE SUPERIOR WEDNESDAY...AND MOVE TO THE LOWER GREAT LAKES BY THURSDAY...USHERING IN PLENTY OF COLD AIR AND THE POTENTIAL FOR NORTHERLY GALES TO 35 KNOTS AS THE PRESSURE GRADIENT TIGHTENS. LOOK FOR DEEP HIGH PRESSURE OVER THE CENTRAL CANADIAN PROVINCES AND NORTHERN PLAINS STATES THURSDAY AFTERNOON. THIS WILL ALLOW A SIZABLE RIDGE OF HIGH PRESSURE SYSTEM TO CROSS LAKE SUPERIOR FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUE MIZ006-085. LAKE EFFECT SNOW ADVY UNTIL 5 AM EST THIS MORNING MIZ007. LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUE MIZ005. LAKE EFFECT SNOW ADVY UNTIL 7 PM EST /6 PM CST/ THIS EVENING MIZ001>003-009-013. LAKE EFFECT SNOW ADVY UNTIL 7 AM EST THIS MORNING MIZ014. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...AJ DISCUSSION...GM AVIATION...AJ MARINE...KF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1218 AM EST MON NOV 17 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 1017 PM EST WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SHORTWAVE DROPPING SSE THRU ERN MANITOBA WITH ANOTHER SUBTLE SHORTWAVE JUST AHEAD OF IT NRN ONTARIO. CWPL SOUNDING SHOWS THE IMPACT THESE SHORTWAVES WILL HAVE. 12Z SOUNDING SHOWED SHARP INVERSION BASED AT 850MB/4.4KFT MSL WHILE 00Z SOUNDING SHOWED INVERSION BASED AT 770MB/7KFT MSL. SO...THESE FEATURES WILL GIVE LES A SOLID BOOST LATE TONIGHT THRU AT LEAST MON MORNING AS THEY HEAD SSE. DESPITE CONSIDERABLY LESS SHEAR IN THE CONVECTIVE LAYER THAN LAST EVENING PER KMQT VAD WIND PROFILE... ONGOING LES OVER SCNTRL LAKE SUPERIOR INTO UPPER MI IS SURPRISINGLY VERY DISORGANIZED...MUCH LIKE LAST EVENING. OUT WEST...POCKET OF DRY WELL MIXED LAYER AIR PER AFTN TAMDAR SOUNDING FROM CYQT HAS HAD A STRONG NEGATIVE IMPACT ON LES. SFC OBS/WEB CAMS SUGGEST -SHSN HAVE BEEN VERY LIGHT DURING THE LATE AFTN INTO EARLY EVENING. MORE RECENTLY...RADAR IMAGERY FROM KDLH IS BEGINNING TO SHOW SOME LES BANDING INTO FAR WRN GOGEBIC COUNTY...SO LES IS PICKING UP IN THAT AREA NOW. GOING FCST APPEARS TO HAVE A GOOD HANDLE ON THE INCREASING LES REGIME OVERNIGHT INTO MON. SO...FOR THE MOST PART...ONLY MINOR CHANGES ARE NEEDED. ONE SIGNIFICANT CHANGE WILL BE TO RUN SRN SCHOOLCRAFT LES ADVY THRU 12Z AS WIND FLOW WILL STILL SUPPORT THE POTENTIAL OF STRONGER LES BANDS REACHING THAT AREA THRU THE OVERNIGHT. ALSO...INCREASED POPS/SNOW AMOUNTS IN NRN DELTA COUNTY (NORTH AND EAST OF RAPID RIVER) OVERNIGHT INTO MON AS THE DOMINANT BAND THAT WILL BE AFFECTING WRN ALGER/ERN MARQUETTE COUNTIES SHOULD EXTEND THAT FAR S GIVEN THE LIFTING INVERSION. && .SYNOPSIS... ISSUED AT 405 PM EST DEEP TROUGH ALOFT CENTERED NEAR JAMES BAY CONTINUES TO FEED COLD AND MOIST AIR ACROSS THE GREAT LAKES. LK EFFECT SNOWS ARE FLYING...MOST NMRS BTWN SHOT POINT IN FAR ERN MARQUETTE COUNTY TO NEWBERRY. DAYTIME ACCUMS WITHIN THE HEAVIER SNOW SHOWERS IN THIS AREA HAVE MAXED OUT BTWN 3-5 INCHES. DESPITE MOISTURE TO H7 AND SUFFICIENT INSTABILITY WITH DELTA T/S OVR 15C...SHIFTING WINDS HAVE NOT ALLOWED DOMINANT BAND TO SET UP AND PERSIST IN ANY ONE SPOT. ELSEWHERE ALONG LAKE SUPERIOR...LK EFFECT IS BENIGN AS DEEP MOISTURE IS LACKING ABOVE 5KFT AS THE UPR LAKES IS BTWN SHORTWAVES THAT ARE ROTATING THROUGH THE REGION. NEXT WAVE OF IMPORTANCE IS DIVING SOUTH ACROSS NORTHERN MANITOBA. ARRIVAL OF THIS WAVE LATE TONIGHT INTO MONDAY MORNING SHAPRENS LAKE INDUCED TROUGH AND WILL INTENSIFY THE LK EFFECT SNOW SHOWERS. LONGWAVE TROUGH AND COOL TEMPS PERSIST THROUGH MUCH OF UPCOMING WEEK...KEEPING LK EFFECT GOING. ANOTHER SHORTWAVE THAT MAY ALLOW FOR AN INCREASE IN THE LK EFFECT IS CURRENTLY OVR NRN BRITISH COLUMBIA. THIS WAVE IS PROGGED TO AFFECT THE UPR LAKES WEDNESDAY INTO THURSDAY. && .SHORT TERM (TONIGHT AND MONDAY)... ISSUED AT 405 PM EST GFS AND THE HIGHER RESOLUTION MODELS REMAIN AT ODDS WITH HOW THE LOW LEVEL WINDS BEHAVE IN THE WAKE OF THE SHORTWAVE LATE TONIGHT INTO MONDAY. FOR THE LAST FEW DAYS...THE GFS HAS REMAINED WITH MORE OF A NW WIND WHILE THE HIGHER RESOLUTION NAM/LOCAL WRF/RUC13 POINT TO SHARPTER TROUGHING AND A NORTH WIND. NOT A BIG DIFFERENCE...BUT THE IMPLICATIONS ON THE FORECAST ARE LARGE. CANADIAN GEM IS A COMPROMISE AND IS FAVORED BY HPC AND LEANED THAT WAY FOR THE GRIDS. NW LOW LEVEL FLOW KEEPS MODERATE LK EFFECT INTO ALGER AND NORTHERN PORTION OF SCHOOLCRAFT THIS EVENING. LOW LEVEL CONVERGENCE WILL STRENGTHEN LATER THIS EVENING INTO THE OVERNIGHT OVR ALGER COUNTY AS WINDS OVR CNTRL CWA BACK WITH BLYR COOLING/DEVELOPING LAND BREEZE. IN THE WRN CWA...LK EFFECT SHOULD PICK UP (UP TO 4" OF ACCUMULATION) AS PERSISTENT MOIST NW FLOW THROUGH H85 IS SUPPLEMENTED BY ADDITIONAL MOISTURE TO H7 COMING IN AHEAD OF THE SHORTWAVE AND AS H85 TEMPS COOL. NW FLOW CONTINUES THROUGH EARLY MONDAY BUT THEN AS SHORTWAVE PASSES THROUGH...LOW LEVEL WINDS BECOME NRLY. REGIONAL GEM SUGGESTS PERIOD OF N WINDS OCCURS BTWN 15Z AND 21Z. WITH THE WIND SHIFT...EXPECT SNOW SHOWERS TO INCREASE OVR FAR WEST AND ALSO INTO ERN MARQUETTE COUNTY. REGIONAL GEM SOUNDINGS INDICATE THAT BY TIME WINDS BECOME NORTH IN THE FAR WEST CWA...THE DEEPER MOISTURE IS LIMITED...SO HEAVY SNOW SHOULD BE FAIRLY SHORT LIVED THERE. IT WILL BE CLOSE THOUGH. DECIDED TO KEEP A HIGH END LES ADVY FOR GOGEBIC INTO ONTONAGON. MEANWHILE...FM WESTERN HALF OF ALGER INTO ERN MARQUETTE COUNTY...SOUNDINGS SHOW IMPRESSIVE INSTABILITY WITH ABUNDANT MOISTURE TO H7-H6 AND H85/H7 TEMPS OF -13C/-22C RESULTING IN LK INDUCED CAPES EXCEEDING 800J/KG. SNOWFALL RATES WITHIN THE MAIN CONVERGENCE BAND IN THIS AREA WILL EXCEED 1"/HR. HAVE DECIDED TO KEEP THE ADVY FOR MARQUETTE COUNTY...WITH EXPECTATION THAT PERIOD OF NRLY WINDS/HEAVIEST SNOW WILL BE SHORT ENOUGH TO PROHIBIT WARNING AMOUNTS. OBVIOUSLY...IF THE MODELS THAT SHOW QUICKER DEPICTION OF WINDS VEERING TO THE NORTH COME TO FRUITION...THEN A WARNING WOULD BE NEEDED FOR MARQUETTE. WARNING AMOUNTS FOR WRN ALGER SEEM A NEAR CERTAINTY. BY LATE MONDAY AFTN...HEAVIEST SNOW WILL SHIFT INTO ALGER COUNTY AS WINDS BEGIN TO BACK IN THE WAKE OF THE SHORTWAVE. .LONG TERM DISCUSSION (MON NGT THRU SUN)... ONGOING LES IN THE N WIND SN BELTS ON MON WL BEGIN TO DRIFT INTO AREAS FVRD BY NW WINDS ON MON NGT OVER THE W AND E OF MQT ON TUE AS THE LLVL FLOW GRDLY BACKS MORE NW WITH THE APRCH OF A HI PRES RDG THAT IS FCST TO MOVE NEAR MPX BY 12Z TUE UNDER SLOWLY RISING HGTS. AS SUBSIDENCE INVRN GRDLY SINKS W-E MON NGT...EXPECT THE HEAVIEST LES TO DIMINISH AS WELL. MODEL DISCREPANCIES NOTED OVER THE LAST FEW DAYS PERSIST WITH THE GFS BEING MORE PROGRESSIVE THAN THE HIER RES MODELS LIKE THE NAM/CNDN/LOCAL WRF-ARW IN BACKING THE FLOW AND LOWERING THE INVRN BASE...ESPECIALLY ON MON NGT. CONSIDERING THE BETTER LLVL RESOLUTION OF THE NAM/CNDN/WRF-ARW...WL TEND TOWARD THE SCENARIO DEPICTED BY THAT GUIDANCE...WHICH WOULD INDICATE GOING HEADLINES MIGHT NEED TO EVENTUALLY BE EXTENDED 6-12 HRS. UNTIL GUIDANCE BECOMES CLEARER...WL HOLD OFF ON CHANGING HEADLINE TIMES. THE NAM/CNDN ACTUALLY BECOME FASTEST THAN THE GFS TO RAISE THE MSLP ON TUE AND PUSH THE RDG AXIS TO THE E. EVEN THOUGH THE INVRN BASE LOWERS STEADILY AS SHOWN ON FCST SDNGS FM BOTH MODELS (ALBEIT AT DIFFERENT RATES)...TEMPS WITHIN THE MIXED LYR BLO THE INVRN ARE LO ENUF (H85 TEMPS ARND -15C AT 06Z TUE) TO FAVOR DENDRITIC SN GROWTH ALMOST TO THE TIME OF ARRIVAL OF RDG AXIS. SO WL APPROXIMATE SN AMTS WITH A HIGH SN/WATER RATIO AOA 20:1. BY LATE TUE...THE FLOW IS PROGGED TO BE W ENUF SO THAT THE ONLY LINGERING LES SHOULD BE OVER THE KEWEENAW AND E OF P53. AS THE RDG AXIS SHIFTS TO THE E ON TUE NGT AND A SHRTWV EMBEDDED WITHIN THE NW FLOW ALF BTWN UPR RDG OVER THE ROCKIES AND TROF OVER THE E APRCHS THE FA...STRONG WAD AS EVIDENCED BY VEERING WINDS WITH HGT AND SHARP ISENTROPIC LIFT ON THE 280K-295K SFCS (H85-6) IS PROGGED TO DVLP OVER UPR MI. ALTHOUGH FCST SNDGS SHOW VERY DRY LLVLS...BOTH THE GFS/NAM TEND TO SATURATE THE LLVLS OVER THE NW FA ENUF TO WARRANT INCLUSION OF CHC POP WHERE H85-7 FGEN IS FCST. BUT PCPN AMTS WL BE LIMITED BY LACK OF SGNFT ABSOLUTE MSTR INFLOW. AS THE SFC LO/ATTENDANT PRES TROF APRCH THE UPR GRT LKS...HAVE SPRD CHC POPS ACRS THE ENTIRE FA. TENDED TO USE A BLEND OF THE 12Z CNDN/NAM MODELS AS THIS NEW GUIDANCE IS BETTER IN LINE WITH NCEP PREFERRED 00Z ECMWF ON HANDLING OF SHRTWV. WITH BETTER 280-295K ISENTROPIC LIFT/H85 QVECTOR CNVGC FCST OVER THE NE FA CLOSER TO SHRTWV TRACK/DOWNWIND OF SOME MOISTENING OFF LK MI...WENT WITH THE HIER POPS ACRS NRN LK SUP/THE ERN FA COUNTIES. IN THE MEDIUM/EXTENDED PD...NCEP INDICATED A PREFERENCE FOR THE 0Z ECMWF FCST...WHICH IS GENERALLY A BIT MORE PROGRESSIVE THAN RECENT GFS FCSTS. COLD AIR INFUSION IN THE WAKE OF SHRTWV (00Z ECMWF SHOWS H85 TEMPS FALLING AS LO AS -17C BY 00Z FRI OVER WRN LK SUP) RESPONSIBLE FOR PCPN CHCS ON WED WL BRING A SHOT OF LES WED NIGT INTO FRI AS GUSTY N WINDS/PSBL GALES ON LK SUP BTWN HI PRES OVER SE CAN AND LO PRES TO THE E DRAG THE COLDER AIR INTO THE UPR LKS. LES ADVYS/WRNGS WL LIKELY BE NEEDED FOR THIS EVENT AT SOME POINT...WL HIGHLIGHT IN THE HWO FOR NOW. THE LES WL DIMINISH FRI/FRI NGT WITH ARRIVAL OF HI PRES RDG...BUT WAD AHEAD OF NEXT SHRTWV/SFC LO PRES EXPECTED TO MOVE E TOWARD THE UPR LKS WL BEGIN TO IMPACT THE FA AS EARLY AS FRI NGT. WL CARRY CHC POPS FOR SOME -SN THRU THE DAY ON SAT...WITH THE HIER POPS ACRS THE NRN FA CLOSER TO LO PRES TRACK FCST BY BULK OF GUIDANCE ACRS NRN LK SUP/ADJOINING ONTARIO. THEN LO CHC POPS FOR SOME LES ON SUN WITH SOME CAD IN THE WAKE OF THE LO. TEMPS AOB NORMAL INTO FRI WL RECOVER CLOSER TO NORMAL OVER THE WEEKEND. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... AT KCMX...VFR CONDITIONS UNDER RELATIVELY DRY WELL MIXED BOUNDARY LAYER WILL TRANSITION TO MVFR DURING THE NIGHT AS APPROACHING UPPER LEVEL DISTURBANCE INCREASES MOISTURE DEPTH AND LIFTS INVERSION. THESE MORE FAVORABLE CONDITIONS FOR LAKE EFFECT -SHSN WILL BE FURTHER ENHANCED DURING THE DAY DUE TO STRENGTHENING LOW-LEVEL CONVERGENCE. SO...EXPECT MVFR CONDITIONS TO TREND DOWNWARD TO IFR IN THE MORNING. LIMITED IMPROVEMENT POSSIBLE LATER AFTN/EVENING AS LOW-LEVEL CONVERGENCE WEAKENS AND UPPER LEVEL DISTURBANCE DEPARTS. AT KSAW...DOWNSLOPING NW FLOW SHOULD RESULT IN PREVAILING VFR CONDITIONS THRU MUCH OF THE NIGHT. EARLY IN THE MORNING... APPROACHING UPPER LEVEL DISTURBANCE WILL PROVIDE MORE FAVORABLE CONDITIONS FOR LAKE EFFECT -SHSN AS MOISTURE DEPTH INCREASES AND INVERSION LIFTS. PREVAILING MVFR CONDITIONS SHOULD DEVELOP BEFORE DAYBREAK WITH DOWNWARD TREND TO IFR MID TO LATE MORNING. DOMINANT/INTENSE SNOW BAND ON A CONVERGENCE ZONE SHIFTING SW OVER SRN LAKE SUPERIOR SHOULD IMPACT KSAW AT SOME POINT IN THE AFTN (PROBABLY EARLY AFTN BASED ON LATEST GUIDANCE). LIFR CONDITIONS A GOOD BET WITH THIS BAND. ONLY LIMITED IMPROVEMENT TO IFR EXPECTED AFTER THE BAND PASSES AS FAVORABLE UPSLOPING NRLY WIND WILL CONTINUE INTO THE EVENING. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS WILL STAY NORTH TO NORTHWEST UP TO 30 KNOTS THROUGH MONDAY BEFORE DIMINISHING AS HIGH PRESSURE BRIEFLY BUILDS IN. A COLD FRONT WILL MOVE THROUGH ON WEDNESDAY WITH SHARPLY COLDER AIR BEHIND IT. N GALES ARE EXPECTED WED NIGHT INTO THU NIGHT IN THE SHARP PRESSURE GRADIENT BETWEEN THE DEPARTING TROUGH OF LOW PRESSURE AND INCOMING HIGH PRESSURE CENTER OVER THE NORTHERN PLAINS. OUTSIDE OF THIS PERIOD EXPECT WINDS UP TO 30 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUE MIZ006-085. LAKE EFFECT SNOW ADVY UNTIL 5 AM EST MON MIZ007. LAKE EFFECT SNOW ADVY FROM 4 AM MON TO 1 AM EST TUE MIZ005. LAKE EFFECT SNOW ADVY UNTIL 7 PM EST /6 PM CST/ MON MIZ002-009. LAKE EFFECT SNOW ADVY UNTIL 7 AM EST MON MIZ014. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. $$ UPDATE...ROLFSON SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KC AVIATION...ROLFSON MARINE...JLA mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1017 PM EST SUN NOV 16 2008 .UPDATE... WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SHORTWAVE DROPPING SSE THRU ERN MANITOBA WITH ANOTHER SUBTLE SHORTWAVE JUST AHEAD OF IT NRN ONTARIO. CWPL SOUNDING SHOWS THE IMPACT THESE SHORTWAVES WILL HAVE. 12Z SOUNDING SHOWED SHARP INVERSION BASED AT 850MB/4.4KFT MSL WHILE 00Z SOUNDING SHOWED INVERSION BASED AT 770MB/7KFT MSL. SO...THESE FEATURES WILL GIVE LES A SOLID BOOST LATE TONIGHT THRU AT LEAST MON MORNING AS THEY HEAD SSE. DESPITE CONSIDERABLY LESS SHEAR IN THE CONVECTIVE LAYER THAN LAST EVENING PER KMQT VAD WIND PROFILE... ONGOING LES OVER SCNTRL LAKE SUPERIOR INTO UPPER MI IS SURPRISINGLY VERY DISORGANIZED...MUCH LIKE LAST EVENING. OUT WEST...POCKET OF DRY WELL MIXED LAYER AIR PER AFTN TAMDAR SOUNDING FROM CYQT HAS HAD A STRONG NEGATIVE IMPACT ON LES. SFC OBS/WEB CAMS SUGGEST -SHSN HAVE BEEN VERY LIGHT DURING THE LATE AFTN INTO EARLY EVENING. MORE RECENTLY...RADAR IMAGERY FROM KDLH IS BEGINNING TO SHOW SOME LES BANDING INTO FAR WRN GOGEBIC COUNTY...SO LES IS PICKING UP IN THAT AREA NOW. GOING FCST APPEARS TO HAVE A GOOD HANDLE ON THE INCREASING LES REGIME OVERNIGHT INTO MON. SO...FOR THE MOST PART...ONLY MINOR CHANGES ARE NEEDED. ONE SIGNIFICANT CHANGE WILL BE TO RUN SRN SCHOOLCRAFT LES ADVY THRU 12Z AS WIND FLOW WILL STILL SUPPORT THE POTENTIAL OF STRONGER LES BANDS REACHING THAT AREA THRU THE OVERNIGHT. ALSO...INCREASED POPS/SNOW AMOUNTS IN NRN DELTA COUNTY (NORTH AND EAST OF RAPID RIVER) OVERNIGHT INTO MON AS THE DOMINANT BAND THAT WILL BE AFFECTING WRN ALGER/ERN MARQUETTE COUNTIES SHOULD EXTEND THAT FAR S GIVEN THE LIFTING INVERSION. && .SYNOPSIS... ISSUED AT 405 PM EST DEEP TROUGH ALOFT CENTERED NEAR JAMES BAY CONTINUES TO FEED COLD AND MOIST AIR ACROSS THE GREAT LAKES. LK EFFECT SNOWS ARE FLYING...MOST NMRS BTWN SHOT POINT IN FAR ERN MARQUETTE COUNTY TO NEWBERRY. DAYTIME ACCUMS WITHIN THE HEAVIER SNOW SHOWERS IN THIS AREA HAVE MAXED OUT BTWN 3-5 INCHES. DESPITE MOISTURE TO H7 AND SUFFICIENT INSTABILITY WITH DELTA T/S OVR 15C...SHIFTING WINDS HAVE NOT ALLOWED DOMINANT BAND TO SET UP AND PERSIST IN ANY ONE SPOT. ELSEWHERE ALONG LAKE SUPERIOR...LK EFFECT IS BENIGN AS DEEP MOISTURE IS LACKING ABOVE 5KFT AS THE UPR LAKES IS BTWN SHORTWAVES THAT ARE ROTATING THROUGH THE REGION. NEXT WAVE OF IMPORTANCE IS DIVING SOUTH ACROSS NORTHERN MANITOBA. ARRIVAL OF THIS WAVE LATE TONIGHT INTO MONDAY MORNING SHAPRENS LAKE INDUCED TROUGH AND WILL INTENSIFY THE LK EFFECT SNOW SHOWERS. LONGWAVE TROUGH AND COOL TEMPS PERSIST THROUGH MUCH OF UPCOMING WEEK...KEEPING LK EFFECT GOING. ANOTHER SHORTWAVE THAT MAY ALLOW FOR AN INCREASE IN THE LK EFFECT IS CURRENTLY OVR NRN BRITISH COLUMBIA. THIS WAVE IS PROGGED TO AFFECT THE UPR LAKES WEDNESDAY INTO THURSDAY. && .SHORT TERM (TONIGHT AND MONDAY)... ISSUED AT 405 PM EST GFS AND THE HIGHER RESOLUTION MODELS REMAIN AT ODDS WITH HOW THE LOW LEVEL WINDS BEHAVE IN THE WAKE OF THE SHORTWAVE LATE TONIGHT INTO MONDAY. FOR THE LAST FEW DAYS...THE GFS HAS REMAINED WITH MORE OF A NW WIND WHILE THE HIGHER RESOLUTION NAM/LOCAL WRF/RUC13 POINT TO SHARPTER TROUGHING AND A NORTH WIND. NOT A BIG DIFFERENCE...BUT THE IMPLICATIONS ON THE FORECAST ARE LARGE. CANADIAN GEM IS A COMPROMISE AND IS FAVORED BY HPC AND LEANED THAT WAY FOR THE GRIDS. NW LOW LEVEL FLOW KEEPS MODERATE LK EFFECT INTO ALGER AND NORTHERN PORTION OF SCHOOLCRAFT THIS EVENING. LOW LEVEL CONVERGENCE WILL STRENGTHEN LATER THIS EVENING INTO THE OVERNIGHT OVR ALGER COUNTY AS WINDS OVR CNTRL CWA BACK WITH BLYR COOLING/DEVELOPING LAND BREEZE. IN THE WRN CWA...LK EFFECT SHOULD PICK UP (UP TO 4" OF ACCUMULATION) AS PERSISTENT MOIST NW FLOW THROUGH H85 IS SUPPLEMENTED BY ADDITIONAL MOISTURE TO H7 COMING IN AHEAD OF THE SHORTWAVE AND AS H85 TEMPS COOL. NW FLOW CONTINUES THROUGH EARLY MONDAY BUT THEN AS SHORTWAVE PASSES THROUGH...LOW LEVEL WINDS BECOME NRLY. REGIONAL GEM SUGGESTS PERIOD OF N WINDS OCCURS BTWN 15Z AND 21Z. WITH THE WIND SHIFT...EXPECT SNOW SHOWERS TO INCREASE OVR FAR WEST AND ALSO INTO ERN MARQUETTE COUNTY. REGIONAL GEM SOUNDINGS INDICATE THAT BY TIME WINDS BECOME NORTH IN THE FAR WEST CWA...THE DEEPER MOISTURE IS LIMITED...SO HEAVY SNOW SHOULD BE FAIRLY SHORT LIVED THERE. IT WILL BE CLOSE THOUGH. DECIDED TO KEEP A HIGH END LES ADVY FOR GOGEBIC INTO ONTONAGON. MEANWHILE...FM WESTERN HALF OF ALGER INTO ERN MARQUETTE COUNTY...SOUNDINGS SHOW IMPRESSIVE INSTABILITY WITH ABUNDANT MOISTURE TO H7-H6 AND H85/H7 TEMPS OF -13C/-22C RESULTING IN LK INDUCED CAPES EXCEEDING 800J/KG. SNOWFALL RATES WITHIN THE MAIN CONVERGENCE BAND IN THIS AREA WILL EXCEED 1"/HR. HAVE DECIDED TO KEEP THE ADVY FOR MARQUETTE COUNTY...WITH EXPECTATION THAT PERIOD OF NRLY WINDS/HEAVIEST SNOW WILL BE SHORT ENOUGH TO PROHIBIT WARNING AMOUNTS. OBVIOUSLY...IF THE MODELS THAT SHOW QUICKER DEPICTION OF WINDS VEERING TO THE NORTH COME TO FRUITION...THEN A WARNING WOULD BE NEEDED FOR MARQUETTE. WARNING AMOUNTS FOR WRN ALGER SEEM A NEAR CERTAINTY. BY LATE MONDAY AFTN...HEAVIEST SNOW WILL SHIFT INTO ALGER COUNTY AS WINDS BEGIN TO BACK IN THE WAKE OF THE SHORTWAVE. .LONG TERM DISCUSSION (MON NGT THRU SUN)... ONGOING LES IN THE N WIND SN BELTS ON MON WL BEGIN TO DRIFT INTO AREAS FVRD BY NW WINDS ON MON NGT OVER THE W AND E OF MQT ON TUE AS THE LLVL FLOW GRDLY BACKS MORE NW WITH THE APRCH OF A HI PRES RDG THAT IS FCST TO MOVE NEAR MPX BY 12Z TUE UNDER SLOWLY RISING HGTS. AS SUBSIDENCE INVRN GRDLY SINKS W-E MON NGT...EXPECT THE HEAVIEST LES TO DIMINISH AS WELL. MODEL DISCREPANCIES NOTED OVER THE LAST FEW DAYS PERSIST WITH THE GFS BEING MORE PROGRESSIVE THAN THE HIER RES MODELS LIKE THE NAM/CNDN/LOCAL WRF-ARW IN BACKING THE FLOW AND LOWERING THE INVRN BASE...ESPECIALLY ON MON NGT. CONSIDERING THE BETTER LLVL RESOLUTION OF THE NAM/CNDN/WRF-ARW...WL TEND TOWARD THE SCENARIO DEPICTED BY THAT GUIDANCE...WHICH WOULD INDICATE GOING HEADLINES MIGHT NEED TO EVENTUALLY BE EXTENDED 6-12 HRS. UNTIL GUIDANCE BECOMES CLEARER...WL HOLD OFF ON CHANGING HEADLINE TIMES. THE NAM/CNDN ACTUALLY BECOME FASTEST THAN THE GFS TO RAISE THE MSLP ON TUE AND PUSH THE RDG AXIS TO THE E. EVEN THOUGH THE INVRN BASE LOWERS STEADILY AS SHOWN ON FCST SDNGS FM BOTH MODELS (ALBEIT AT DIFFERENT RATES)...TEMPS WITHIN THE MIXED LYR BLO THE INVRN ARE LO ENUF (H85 TEMPS ARND -15C AT 06Z TUE) TO FAVOR DENDRITIC SN GROWTH ALMOST TO THE TIME OF ARRIVAL OF RDG AXIS. SO WL APPROXIMATE SN AMTS WITH A HIGH SN/WATER RATIO AOA 20:1. BY LATE TUE...THE FLOW IS PROGGED TO BE W ENUF SO THAT THE ONLY LINGERING LES SHOULD BE OVER THE KEWEENAW AND E OF P53. AS THE RDG AXIS SHIFTS TO THE E ON TUE NGT AND A SHRTWV EMBEDDED WITHIN THE NW FLOW ALF BTWN UPR RDG OVER THE ROCKIES AND TROF OVER THE E APRCHS THE FA...STRONG WAD AS EVIDENCED BY VEERING WINDS WITH HGT AND SHARP ISENTROPIC LIFT ON THE 280K-295K SFCS (H85-6) IS PROGGED TO DVLP OVER UPR MI. ALTHOUGH FCST SNDGS SHOW VERY DRY LLVLS...BOTH THE GFS/NAM TEND TO SATURATE THE LLVLS OVER THE NW FA ENUF TO WARRANT INCLUSION OF CHC POP WHERE H85-7 FGEN IS FCST. BUT PCPN AMTS WL BE LIMITED BY LACK OF SGNFT ABSOLUTE MSTR INFLOW. AS THE SFC LO/ATTENDANT PRES TROF APRCH THE UPR GRT LKS...HAVE SPRD CHC POPS ACRS THE ENTIRE FA. TENDED TO USE A BLEND OF THE 12Z CNDN/NAM MODELS AS THIS NEW GUIDANCE IS BETTER IN LINE WITH NCEP PREFERRED 00Z ECMWF ON HANDLING OF SHRTWV. WITH BETTER 280-295K ISENTROPIC LIFT/H85 QVECTOR CNVGC FCST OVER THE NE FA CLOSER TO SHRTWV TRACK/DOWNWIND OF SOME MOISTENING OFF LK MI...WENT WITH THE HIER POPS ACRS NRN LK SUP/THE ERN FA COUNTIES. IN THE MEDIUM/EXTENDED PD...NCEP INDICATED A PREFERENCE FOR THE 0Z ECMWF FCST...WHICH IS GENERALLY A BIT MORE PROGRESSIVE THAN RECENT GFS FCSTS. COLD AIR INFUSION IN THE WAKE OF SHRTWV (00Z ECMWF SHOWS H85 TEMPS FALLING AS LO AS -17C BY 00Z FRI OVER WRN LK SUP) RESPONSIBLE FOR PCPN CHCS ON WED WL BRING A SHOT OF LES WED NIGT INTO FRI AS GUSTY N WINDS/PSBL GALES ON LK SUP BTWN HI PRES OVER SE CAN AND LO PRES TO THE E DRAG THE COLDER AIR INTO THE UPR LKS. LES ADVYS/WRNGS WL LIKELY BE NEEDED FOR THIS EVENT AT SOME POINT...WL HIGHLIGHT IN THE HWO FOR NOW. THE LES WL DIMINISH FRI/FRI NGT WITH ARRIVAL OF HI PRES RDG...BUT WAD AHEAD OF NEXT SHRTWV/SFC LO PRES EXPECTED TO MOVE E TOWARD THE UPR LKS WL BEGIN TO IMPACT THE FA AS EARLY AS FRI NGT. WL CARRY CHC POPS FOR SOME -SN THRU THE DAY ON SAT...WITH THE HIER POPS ACRS THE NRN FA CLOSER TO LO PRES TRACK FCST BY BULK OF GUIDANCE ACRS NRN LK SUP/ADJOINING ONTARIO. THEN LO CHC POPS FOR SOME LES ON SUN WITH SOME CAD IN THE WAKE OF THE LO. TEMPS AOB NORMAL INTO FRI WL RECOVER CLOSER TO NORMAL OVER THE WEEKEND. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KCMX...EXPECT VFR/OCCASIONAL MVFR CONDITIONS TO PREVAIL THRU THE EVENING UNDER RELATIVELY DRY WELL MIXED BOUNDARY LAYER. OVERNIGHT... APPROACHING UPPER LEVEL DISTURBANCE WILL PROVIDE MORE FAVORABLE CONDITIONS FOR LAKE EFFECT -SHSN AS MOISTURE DEPTH INCREASES AND INVERSION LIFTS. PREVAILING MVFR CONDITIONS WILL DEVELOP OVERNIGHT WITH DOWNWARD TREND TO IFR MON MORNING AS STRENGTHENING LOW-LEVEL CONVERGENCE FURTHER ENHANCES -SHSN. LIMITED IMPROVEMENT POSSIBLE LATER MON AFTN AS LOW-LEVEL CONVERGENCE WEAKENS AND UPPER LEVEL DISTURBANCE DEPARTS. AT KSAW...DOWNSLOPING NW FLOW SHOULD RESULT IN PREVAILING VFR CONDITIONS THRU MUCH OF THE NIGHT. EARLY MON MORNING...APPROACHING UPPER LEVEL DISTURBANCE WILL PROVIDE MORE FAVORABLE CONDITIONS FOR LAKE EFFECT -SHSN AS MOISTURE DEPTH INCREASES AND INVERSION LIFTS. PREVAILING MVFR CONDITIONS SHOULD DEVELOP BEFORE DAYBREAK WITH DOWNWARD TREND TO IFR MID TO LATE MON MORNING. DOMINANT/INTENSE SNOW BAND ON A CONVERGENCE ZONE SHIFTING SW OVER SRN LAKE SUPERIOR SHOULD IMPACT KSAW AT SOME POINT MON AFTN (PROBABLY EARLY AFTN BASED ON LATEST GUIDANCE). LIFR CONDITIONS WILL BE LIKELY WITH THIS BAND. ONLY LIMITED IMPROVEMENT TO IFR EXPECTED AFTER THE BAND PASSES AS FAVORABLE UPSLOPING NRLY WIND WILL CONTINUE. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... WINDS WILL STAY NORTH TO NORTHWEST UP TO 30 KNOTS THROUGH MONDAY BEFORE DIMINISHING AS HIGH PRESSURE BRIEFLY BUILDS IN. A COLD FRONT WILL MOVE THROUGH ON WEDNESDAY WITH SHARPLY COLDER AIR BEHIND IT. N GALES ARE EXPECTED WED NIGHT INTO THU NIGHT IN THE SHARP PRESSURE GRADIENT BETWEEN THE DEPARTING TROUGH OF LOW PRESSURE AND INCOMING HIGH PRESSURE CENTER OVER THE NORTHERN PLAINS. OUTSIDE OF THIS PERIOD EXPECT WINDS UP TO 30 KNOTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 1 AM EST TUE MIZ006-085. LAKE EFFECT SNOW ADVY UNTIL 5 AM EST MON MIZ007. LAKE EFFECT SNOW ADVY FROM 4 AM MON TO 1 AM EST TUE MIZ005. LAKE EFFECT SNOW ADVY UNTIL 7 PM EST /6 PM CST/ MON MIZ002-009. LAKE EFFECT SNOW ADVY UNTIL 7 AM EST MON MIZ014. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. $$ UPDATE...ROLFSON SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KC AVIATION...ROLFSON MARINE...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 100 PM EST SUN NOV 16 2008 LATEST UPDATE...LONG TERM AND AVIATION... .SYNOPSIS...(330 AM EST SUN NOV 16 2008) A COUPLE OF LOW PRESSURE SYSTEMS WILL MOVE ACROSS THE GREAT LAKES DURING THE NEXT TWO DAYS AND EACH WILL BRING A REINFORCING SHOT OF COLDER AIR AND LAKE EFFECT SNOW SHOWERS. LIGHT ACCUMULATIONS ARE POSSIBLE ESPECIALLY MONDAY AND MONDAY NIGHT ACROSS FAR SOUTHWEST LOWER MICHIGAN. && .SHORT TERM...(1042 AM EST SUN NOV 16 2008) (REST OF TODAY THROUGH TUESDAY) I DID A QUICK FORECAST UPDATE TO INCREASE THE SNOW ACCUMULATIONS TO SHOW ANOTHER INCH OF SNOW WILL FALL THE REST OF THE DAYLIGHT HOURS OF TODAY. I DID THAT SINCE WE HAVE HAD... VIA COCORAHS... SPOTTERS AND COOPERATIVE OBSERVATIONS... REPORTS OF BETWEEN A HALF AND ONE AND A HALF INCHES OF SNOW ALREADY. SINCE THEN THE RADAR SNOW ACCUMULATION ALGORITHM...WHICH WAS DEAD ON WITH THE PREVIOUS REPORTS... SHOWS UP TO 2 INCHES HAS FALLEN ALREADY NOW (1030 AM). THE LATEST SATELLITE LOOPS SHOW (WATER VAPOR AND IR) AND RADAR MOSAIC LOOPS SUGGEST A DECENT SHORTWAVE HEADING OUR WAY THIS MORNING. THE RUC AND GFS SHOW THE HEAVIEST PRECIPITATION RATES WILL BE THIS AFTERNOON. I COULD SEE ANOTHER INCH OR TWO FALLING. I WONDER OF THE RATE OF FALL WILL BE OFFSET BY THE AIR TEMPERATURE BEING JUST ABOVE FREEZING AND IT IS DURING THE DAY TIME...SO MOST OF THE SNOW WILL MELT AS IT FALLS (HOWEVER IT IS NOT DOING THAT AT OUR OFFICE...LOOKS LIKE ABOUT .2 INCH HERE SO FAR). SO I WILL GO WITH ANOTHER INCH IN THE FORECAST. IF IT KEEPS ACCUMULATING I WILL UPDATED AGAIN. CLEARLY THE 00Z NAM QPF WAS TO LIGHT FOR TODAY. PREVIOUS DISCUSSION...WINDS WILL VEER TO THE NW TONIGHT BEHIND THE DEPARTING WAVE. AS H8 TEMPS FALL TO -11C...LAKE DELTA T/S CLIMB INTO THE MID 20S. LAKE EFFECT WILL GET GOING WITH THE FAR SW CWA THE FAVORED AREA. A COUPLE OF INCHES IS POSSIBLE IN THIS AREA. ACCUMS SHOULD BE HELD IN CHECK TO SOME DEGREE SINCE THE DGZ ISN/ ALL THAT DEEP BUT A COUPLE OF INCHES ARE POSSIBLE. ANOTHER SHORT WAVE IS PROGD TO MOVE INTO THE REGION MONDAY. STRONG DPVA WITH THIS SYSTEM. WE/LL LIKELY SEE A LITTLE SYNOPTIC SNOW WITH THIS SYSTEM. INVERSION HEIGHTS BRIEFLY SPIKE UP TO AROUND 10K FT MONDAY EVENING. THE DIFFERENCE WITH THIS WAVE IS THAT BOUNDARY LAYER WINDS ARE PROGD TO VEER TO THE NORTH WHICH PUTS THE POINTS IN THE NW CWA AND FAR SW VAN BUREN COUNTY IN PLAY. THERE COULD BE SEVERAL INCHES OF SNOW IF ONE MAIN LAKE BAND SETS UP. I/M NOT CONFIDENT ENOUGH IN THIS SETUP TO ISSUE A WATCH THOUGH. BUT WE/LL KEEP AN EYE ON IT. THE ERN CWA PROBABLY WON/T SEE MUCH SNOW MONDAY NIGHT IN NORTH FLOW. SHSN SHOULD SPREAD INLAND TUESDAY AS THE WAVE DEPARTS AND WINDS BACK TO THE WNW AS WARN AIR ADVECTION DEVELOPS ON THE BACK SIDE OF THE DEPARTING UPPER TROUGH. BUT MOISTURE WILL BE WANING AND ACCUMS ARE NOT EXPECTED. && .LONG TERM...(100 PM EST SUN NOV 16 2008) (WEDNESDAY THROUGH SUNDAY) A WEAK LOW PRESSURE SYSTEM DROPPING DOWN FROM THE NW WILL BRING SOME SNOW SHOWERS WEDNESDAY. ANOTHER SHOT OF COLD AIR WILL FILTER IN BEHIND THAT SYSTEM WEDNESDAY NIGHT THROUGH FRIDAY WITH LAKE EFFECT SNOW SHOWERS ANTICIPATED THROUGH THURSDAY NIGHT INTO FRIDAY BEFORE ENDING. THE SFC HIGH PRESSURE RIDGE WILL RESULT IN DRY WX FROM LATE FRIDAY THROUGH MOST OF THE WEEKEND. SW FLOW ON THE BACK SIDE OF THE SFC RIDGE WILL RESULT IN A MODERATING TREND OF TEMPS NEXT WEEKEND. && .MARINE...(330 AM EST SUN NOV 16 2008) WE EXTENDED THE SCA THROUGH TUESDAY. SECONDARY SHORT WAVE AND ASSOCIATED SHOT OF COLD AIR WILL KEEP WAVES WELL ABOVE 4 FT INTO TUESDAY. && .AVIATION...(100 PM EST SUN NOV 16 2008) WNW FLOW LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO DEVELOP THIS AFTERNOON. CONDITIONS AT ALL TAF SITES THIS AFTERNOON INTO THE EARLY EVENING WILL BE QUITE VARIABLE. PRIMARILY VFR TO MVFR CONDITIONS WILL OCCUR... BUT NUMEROUS REDUCTIONS INTO THE IFR FLIGHT CATEGORY WILL CONTINUE DUE TO VISBYS DOWN TO A MILE OR TWO IN THE HEAVIER SNOW BANDS. WIND SPEEDS TONIGHT WILL DIMINISH AND VEER MORE TO THE NW. AS A RESULT WE BELIEVE LAKE EFFECT SNOW SHOWERS LATER TONIGHT WILL MAINLY AFFECT THE AREA NEAR AND PARTICULARLY WEST OF US-131. HOWEVER SNOW SHOWER ACTIVITY WILL INCREASE IN COVERAGE AND INTENSITY ON MONDAY AS COLDER AIR MOVES IN AND NW WIND SPEEDS INCREASE... CARRYING THE SNOW BANDS WELL INLAND BETWEEN 14Z AND 18Z MON. && .HYDROLOGY...(330 AM EST SUN NOV 16 2008) NO HYDRO ISSUES DUE TO LIMITED QPF. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY FROM ST JOE TO MANISTEE THROUGH TUESDAY. && $$ SYNOPSIS: 93 SHORT TERM: 93 WDM LONG TERM: LAURENS MARINE: 93 AVIATION: LAURENS HYDROLOGY: 93 mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1042 AM EST SUN NOV 16 2008 LATEST UPDATE...SHORT TERM... .SYNOPSIS...(330 AM EST SUN NOV 16 2008) A COUPLE OF LOW PRESSURE SYSTEMS WILL MOVE ACROSS THE GREAT LAKES DURING THE NEXT TWO DAYS AND EACH WILL BRING A REINFORCING SHOT OF COLDER AIR AND LAKE EFFECT SNOW SHOWERS. LIGHT ACCUMULATIONS ARE POSSIBLE ESPECIALLY MONDAY AND MONDAY NIGHT ACROSS FAR SOUTHWEST LOWER MICHIGAN. && .SHORT TERM...(1042 AM EST SUN NOV 16 2008) (REST OF TODAY THROUGH TUESDAY) I DID A QUICK FORECAST UPDATE TO INCREASE THE SNOW ACCUMULATIONS TO SHOW ANOTHER INCH OF SNOW WILL FALL THE REST OF THE DAYLIGHT HOURS OF TODAY. I DID THAT SINCE WE HAVE HAD... VIA COCORAHS... SPOTTERS AND COOPERATIVE OBSERVATIONS... REPORTS OF BETWEEN A HALF AND ONE AND A HALF INCHES OF SNOW ALREADY. SINCE THEN THE RADAR SNOW ACCUMULATION ALGORITHM...WHICH WAS DEAD ON WITH THE PREVIOUS REPORTS... SHOWS UP TO 2 INCHES HAS FALLEN ALREADY NOW (1030 AM). THE LATEST SATELLITE LOOPS SHOW (WATER VAPOR AND IR) AND RADAR MOSAIC LOOPS SUGGEST A DECENT SHORTWAVE HEADING OUR WAY THIS MORNING. THE RUC AND GFS SHOW THE HEAVIEST PRECIPITATION RATES WILL BE THIS AFTERNOON. I COULD SEE ANOTHER INCH OR TWO FALLING. I WONDER OF THE RATE OF FALL WILL BE OFFSET BY THE AIR TEMPERATURE BEING JUST ABOVE FREEZING AND IT IS DURING THE DAY TIME...SO MOST OF THE SNOW WILL MELT AS IT FALLS (HOWEVER IT IS NOT DOING THAT AT OUR OFFICE...LOOKS LIKE ABOUT .2 INCH HERE SO FAR). SO I WILL GO WITH ANOTHER INCH IN THE FORECAST. IF IT KEEPS ACCUMULATING I WILL UPDATED AGAIN. CLEARLY THE 00Z NAM QPF WAS TO LIGHT FOR TODAY. PREVIOUS DISCUSSION...WINDS WILL VEER TO THE NW TONIGHT BEHIND THE DEPARTING WAVE. AS H8 TEMPS FALL TO -11C...LAKE DELTA T/S CLIMB INTO THE MID 20S. LAKE EFFECT WILL GET GOING WITH THE FAR SW CWA THE FAVORED AREA. A COUPLE OF INCHES IS POSSIBLE IN THIS AREA. ACCUMS SHOULD BE HELD IN CHECK TO SOME DEGREE SINCE THE DGZ ISN/ ALL THAT DEEP BUT A COUPLE OF INCHES ARE POSSIBLE. ANOTHER SHORT WAVE IS PROGD TO MOVE INTO THE REGION MONDAY. STRONG DPVA WITH THIS SYSTEM. WE/LL LIKELY SEE A LITTLE SYNOPTIC SNOW WITH THIS SYSTEM. INVERSION HEIGHTS BRIEFLY SPIKE UP TO AROUND 10K FT MONDAY EVENING. THE DIFFERENCE WITH THIS WAVE IS THAT BOUNDARY LAYER WINDS ARE PROGD TO VEER TO THE NORTH WHICH PUTS THE POINTS IN THE NW CWA AND FAR SW VAN BUREN COUNTY IN PLAY. THERE COULD BE SEVERAL INCHES OF SNOW IF ONE MAIN LAKE BAND SETS UP. I/M NOT CONFIDENT ENOUGH IN THIS SETUP TO ISSUE A WATCH THOUGH. BUT WE/LL KEEP AN EYE ON IT. THE ERN CWA PROBABLY WON/T SEE MUCH SNOW MONDAY NIGHT IN NORTH FLOW. SHSN SHOULD SPREAD INLAND TUESDAY AS THE WAVE DEPARTS AND WINDS BACK TO THE WNW AS WARN AIR ADVECTION DEVELOPS ON THE BACK SIDE OF THE DEPARTING UPPER TROUGH. BUT MOISTURE WILL BE WANING AND ACCUMS ARE NOT EXPECTED. && .LONG TERM...(330 AM EST SUN NOV 16 2008) (TUESDAY NIGHT THROUGH SATURDAY) THE 00Z MODEL RUNS SHOW GOOD CONSISTENCY WITH THE PREVIOUS RUNS SO THERE WAS NO REASON TO MAKE ANY SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST. STILL EXPECT SCATTERED SNOW SHOWERS MUCH OF THE PERIOD AS A WEAK SHORTWAVE TROUGH MOVES THROUGH WEDNESDAY FOLLOWED BY A SHOT OF COLD AIR ON THURSDAY. SFC HIGH MOVES EAST FRIDAY WITH SNOW SHOWERS ENDING BY LATE IN THE DAY WITH FAIR WEATHER FRIDAY NIGHT AND SATURDAY. && .MARINE...(330 AM EST SUN NOV 16 2008) WE EXTENDED THE SCA THROUGH TUESDAY. SECONDARY SHORT WAVE AND ASSOCIATED SHOT OF COLD AIR WILL KEEP WAVES WELL ABOVE 4 FT INTO TUESDAY. && .AVIATION...(617 AM EST SUN NOV 16 2008) LAKE EFFECT SNOW SHOWERS WILL CONTINUE INTO TONIGHT WITH SOME TEMPORARY REDUCTIONS IN VISBYS AND CEILINGS. CONDITIONS BECOME A LITTLE MORE FAVORABLE TONIGHT FOR THE SNOW TO INCREASE IN INTENSITY BUT VISBYS LESS THAN 2 MILES SHOULD NOT BE EXTENSIVE OUTSIDE OF MKG AND AZO. && .HYDROLOGY...(330 AM EST SUN NOV 16 2008) NO HYDRO ISSUES DUE TO LIMITED QPF. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY FROM ST JOE TO MANISTEE THROUGH TUESDAY. && $$ SYNOPSIS: 93 SHORT TERM: 93 WDM LONG TERM: OSTUNO MARINE: 93 AVIATION: OSTUNO HYDROLOGY: 93 mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1218 AM EST SUN NOV 16 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 935 PM EST NOT MUCH IN THE WAY OF LES IS OCCURRING OVER WRN UPPER MI THIS EVENING. UPSTREAM 00Z KINL SOUNDING TELLS THE STORY. FROM 12Z TO 00Z...INVERSION FELL FROM 750MB/7.8KFT MSL TO 880MB/3.7KFT MSL AND THE BOUNDARY LAYER BECAME WELL MIXED/DRIED OUT. TO THE E...LONGER FETCH INTO NCNTRL UPPER MI WITH ASSISTANCE OF PRECONDITIONING FROM LAKE NIPIGON IS STILL YIELDING NUMEROUS SHSN. KMQT VAD WIND PROFILE SHOWS CLOUD TOPS TO AROUND 11KFT MSL...BUT IT ALSO SHOWS QUITE A BIT OF SHEAR WITH WINDS VEERING FROM NW NEAR THE SFC TO NE TOWARD CLOUD TOP. THUS...THE SHSN AREN`T WELL ORGANIZED INTO BANDS. NONETHELESS...WITH OCCASIONAL REFLECTIVITIES IN EXCESS OF 28DBZ... THERE SHOULD BE SOME BRIEF HEAVY SNOW AT TIMES. HOWEVER...THE HIGH REFLECTIVITIES MAY JUST BE MORE INDICATIVE OF SNOW PELLETS/GRAUPEL AS A COUPLE OF SPOTTER REPORTS INDICATE. UPSTREAM 00Z CWPL SOUNDING SHOWED A SHARP INVERSION BASED AT 850MB/4.6KFT MSL. AS INVERSION LWRS PER 00Z KINL/CWPL SOUNDINGS AND SOMEWHAT DRIER BOUNDARY LAYER AIR SPREADS OVER CNTRL/ERN LAKE SUPERIOR...EXPECT -SHSN TO BECOME A LITTLE MORE DISORGANIZED AND DIMINISH A BIT DURING THE NEXT SEVERAL HRS. THERE ARE ALREADY INDICATIONS OF THIS UNDERWAY IN THE LATEST FEW RADAR SCANS. LATER TONIGHT...SHORTWAVE CURRENTLY HEADING SE INTO SRN MANITOBA WILL REACH THE UPPER MIDWEST. ALTHOUGH FORCING WITH THIS FEATURE WILL PASS MOSTLY SW OF THE FCST AREA... THERE WILL BE A DEEPENING OF THE MOISTURE PROFILE LATE TONIGHT AND MORE SO SUN MORNING AS REPRESENTED BY THE 00Z CYQD SOUNDING. SO...EXPECT AN INCREASE IN -SHSN COVERAGE/INTENSITY LATE TONIGHT THRU SUN MORNING FROM W TO E. INHERITED FCST LOOKS ON TRACK WITH THIS SCENARIO...BUT APPEARS A LITTLE QUICK IN INCREASING SHSN. SO... UPDATE WILL REFLECT A LITTLE DELAY IN INCREASING COVERAGE OF -SHSN UNTIL LATER IN THE NIGHT INTO SUN MORNING. ADDITIONAL SNOW ACCUMULATIONS THRU 12Z SUN FOR THE GENERAL NW FLOW SNOWBELTS SHOULD BE MINIMAL...ONLY AN INCH OR TWO DUE TO LATE ARRIVAL OF MORE FAVORABLE CONDITIONS. LES SHOULD BE MOST FOCUSED FROM NEAR KIWD TO ROCKLAND OVER THE W AND BTWN MARQUETTE/MUNISING OVER THE NCNTRL DUE TO LAND BREEZE ENHANCED LOW-LEVEL CONVERGENCE. QUICK CHECK OF INCOMING 00Z NAM SUGGESTS ONGOING HEADLINES THRU MON ARE ON TRACK. && .SYNOPSIS... ISSUED AT 400 PM EST 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF FM HUDSON BAY S THRU THE GRT LKS INTO THE SE STATES SANDWICHED BTWN RDG OVER THE W AND ANOTHER IN THE WRN ATLANTIC. POTENT SHRTWV LIFTING OUT OF THE BASE OF THE TROF IS INDUCING CYCLOGEN IN THE UPR OH VALLEY. THE UPR GRT LKS IS DOMINATED BY THE CHILLY NLY FLOW BTWN THIS DVLPG LO PRES AND SFC HI PRES FM THE PLAINS TO LK WINNIPEG DOWNSTREAM OF WRN RDG. THE PASSAGE OF COLDER AIR (12Z H85 TEMP AT YPL WAS -17C VS -8C AT GRB) ACRS LK SUP HAS RESULTED IN NMRS SHSN IN THE SN BELTS FVRD BY THE NNW FLOW...ESPECIALLY OVER ERN MQT/WRN ALGER COUNTIES WHERE 12Z NAM/RECENT HIER RES MODELS SHOW SHARPER H925 CNVGC AND MOISTENING FM LK NIPIGON APPEARS TO BE ENHANCING SHSN INTENSITY. REPORT FM TRAUNIK IN WRN ALGER COUNTY INDICATED 2 INCHES OF SN AS OF 1630Z. ALTHOUGH RECENT TAMDAR SDNGS AND STLT IMAGERY SUG SOME DEEPER MSTR IS PRESENT...OVERALL DNVA/DEEP QVECTOR DVGC/SUBSIDENCE WITHIN DENDRITIC SN GROWTH ZN IS TENDING TO LIMIT THE INTENSITY OF THE LES. 12Z YPL SDNG SHOWED SHARP INVRN ARND H85...AND NNW FLOW ALF APPEARS TO BE ADVCTING DRIER MID LVL AIR FM THIS LOCATION S TOWARD THE FA. PLENTY OF SC NOTED UPSTREAM IN ONTARIO TO RDG AXIS NEAR LK WINNIPEG. FARTHER UPSTREAM...A POTENT SHRTWV OVER NRN ALBERTA IS TOPPING WRN RDG WITH H3 WIND MAX UP TO 140KT. && .SHORT TERM DISCUSSION (TNGT AND SUN)... ISSUED AT 400 PM EST MAIN FCST CONCERNS DURING THIS PD ARE LES TRENDS/INTENSITY. FOR TNGT...LLVL FLOW IS PROGGED TO BACK MORE NW THRU MIDNGT AS DVLPG LO TO THE SE LIFTS INTO SE CAN. ALTHOUGH HGTS ARE FCST TO FALL SLOWLY...MODEL FCST SDNGS IN GENERAL SHOW INVRN BASE ARND H85 STRENGTHING THRU 06Z WITH DNVA/LARGER SCALE QVECTOR DVGC ON THE NW FLANK OF THIS SYS ALSO HELPING TO REDUCE MID LVL MSTR. BACKING WINDS WL CAUSE EXISTING LES BANDS TO DRIFT ACCORDINGLY THRU THE NGT. AS SHRTWV FM ALBERTA SLIDES SE INTO MN LATE TNGT...SOME DPVA/QVECTOR CNVGC WL ARRIVE AND CAUSE LLVL WINDS TO VEER AGAIN A BIT...AT LEAST OVER LK SUP AND ESPECIALLY OVER THE ERN PART OF THE LK WITH LAND BREEZE OFF ONTARIO. EXPECT LOWER MIN TEMPS NEAR THE WI BORDER IN MORE BACKED LLVL FLOW THIS EVNG WITH LESS LK MODERATION IN THAT AREA. THE ENHANCED LLVL CNVGC AT EDGE OF DVLPG LAND BREEZE WL ENHANCE LLVL CNVGC AND LES INTENSITY IN ONTONAGON/GOGEBIC AND ALGER COUNTIES. SHRTWV/BETTER DPVA WL SLIDE SE TO THE S OF UPR MI TMRW...SO THERE WL BE LIMITED DYNAMIC BOOST FOR THE ONGOING LES. SO PCPN CHCS WL BE PRIMARILY RELATED TO LES. 12Z NAM/RUC13/LOCAL WRF-ARW RUNS SHOW PERSISTENT LLVL CNVGC OVER ALGER/NRN SCHOOLCRAFT COUNTIES...SO WL GO WITH A HIER POP. IN FACT...NAM FCST SDNG FOR THE P53 AREA SHOWS INVRN BASE LIFTING TO H75 WITH MORE FVRBL OMEGA IN DENDRITIC SN GROWTH ZN IN PRESENCE OF SLOWLY FALLING H85 TEMPS PUSHING LK WATER-H85 DELTA T ARND 17C. CONSIDERING EXCELLENT AGREEMENT AMONG HI RES MODELS AND QPF FM THIS GUIDANCE/FVRBL DENDRITIC SN GROWTH/HI SNOW/WATER RATIO...DECIDED TO POST LES WRNG FOR ALGER/NRN SCHOOLCRAFT ZNS FOR LATE TNGT THRU THE DAY ON SUN. WENT WITH ADVY FOR SRN SCHOOLCRAFT CONSIDERING LOWER ADVY THRESHOLD FOR THAT AREA. NAM SHOWS SOME DEEPER MSTR MOVING INTO THE WRN ZNS AS WELL DURING THE MRNG ON NRN FLANK OF SHRTWV STREAKING TO THE S...WITH FVRBL LLVL CNVGC PROFILE DURING THIS TIME AS WELL. HOWEVER...THE OMEGA PROFILE RELATIVE TO THE DENDRITIC SN GROWTH ZN IS NOT AS FVRBL. SINCE THE DURATION OF DEEPER MSTR IS ONLY ABOUT 6 HRS...WL NOT POST ADVY FOR THIS AREA ATTM. ETA/GFS MOS FCST HI TEMPS ON MON ARE SIMILAR AND SEEM RSNBL. .LONG TERM (SUNDAY NIGHT THROUGH NEXT SATURDAY)... FOR THE MOST PART...LARGE TROUGH DEVELOPING OVER EASTERN CANADA TO THE GREAT LAKES AND INTO THE NE CONUS REMAINS IN PLACE THROUGH THIS WEEK AS LARGE RIDGE PERSISTS FM THE WESTERN CONUS INTO SW CANADA. COUPLE OF SHORTWAVES DIVING INTO THE TROUGH INTERRUPT THE GENERAL NORTH/NORTHWEST FLOW PATTERN...BUT BASICALLY THE PATTERN CONTINUES THROUGH FRIDAY. NEXT WEEKEND...THE WESTERN RIDGE IS SHUNTED EAST AS STRONGER TROUGH BEGINS TO SHIFT INTO WRN CONUS. RESULT WOULD BE A MORE ZONAL UPPER FLOW WITH MODERATING TEMPS AND LK EFFECT COMING TO AN END. HOWEVER...GIVEN SIZABLE DIFFERENCES IN THE WAY MODELS HANDLE THE PATTERN BEYOND DAY 6 AND NOISY OUTPUT IN THE H5 SPAGHETTI CHARTS FM THE GFS AND CANADIAN ENSEMBLE FORECAST SYSTEMS THERE IS BLO AVERAGE CONFIDENCE IN THE DETAILS FOR NEXT WEEKEND. SUNDAY NIGHT AND MONDAY...ACTIVE LK EFFECT REGIME CONTINUES. INSTABILITY WILL ONLY INCREASE AS H85 TEMPS COOL TO AROUND -15C WEST AND -12C IN THE EAST BY 12Z MONDAY...RESULTING IN LAKE INDUCED CAPES 500-800J/KG...PRETTY SIGNIFICANT. A DIFFERENCE FM GUIDANCE FM 24 HR AGO IS LESS DEEP MOISTURE ON MONDAY MORNING...SO ENHANCEMENT FACTOR IS NOT QUITE AS EVIDENT. THERMAL PROFILE REMAINS VERY FAVORABLE THOUGH AS LAKE EFFECT CLOUD LAYER IS WITHIN THE BEST DENDRITIC SNOW GROWTH ZONE OF TEMPS FM -12C TO -18C. SO...EVEN WITHOUT THE SYNOPTIC SUPPORT...SIGNIFICANT LK EFFECT SNOW LOOKS LIKELY. THE QUESTION IS WHERE WILL HEAVIER CONVERGENCE SNOW SHOWERS DEVELOP. MAIN AREA THAT PREFERRED ECMWF AND THE HIGHER RESOLUTION MODELS...NAM/RUC13/LOCAL WRF/REGIONAL CANADIAN...INDICATE FOR MAXIMIM LOW LEVEL CONVERGENCE IS OVR MARQUETTE COUNTY INTO WRN ALGER COUNTY AND TO SOME EXTENT ALSO OVR FAR WRN CWA NEAR IWD. WITH THE NNW FLOW...ADDITIONAL MOISTURE FM LAKE NIPEGON COULD ALSO INTENSIFY THE CONVERGENCE SNOW BAND...AS OCCURS ON SUNDAY. TIME FRAME FOR THE HEAVIEST SNOW WOULD BE LATE SUNDAY NIGHT AND INTO MUCH OF MONDAY WHEN TROUGH PUSHES THROUGH NRN UPR MI. DECIDED TO PUT UP A WATCH FOR MARQUETTE COUNTY AS THERE ARE EMERGING SIGNALS THAT THIS CONVERGENCE BAND WILL SHIFT ONSHORE LATE SUNDAY NIGHT. UPSLOPE FLOW CONTRIBUTING TO AN ALREADY WELL DEVELOPED SNOW BAND COULD LEAD TO A LOT OF SNOW. ALSO...ALTHOUGH IT HAS POTENTIAL TO BE CONFUSING...THINK AN ADDITIONAL WATCH FOR ALGER SUNDAY NIGHT INTO MONDAY IS WARRENTED AS WELL. WOULD LIKE MODELS COME INTO LINE WITH MORE OF A 360 FLOW FOR FAR WRN UPR MI INSTEAD OF A 330 FLOW BEFORE RUNNING WITH A WATCH THERE. EVEN SO...IF CONVERGENCE AREA CAN DEVELOP AND MAINTAIN FOR ANY APPRECIABLE DURATION SUNDAY NIGHT INTO MONDAY OVR GOGEBIC COUNTY...LOCALIZED WARNING AMOUNTS ARE NOT OUT OF THE QUESTION...ESPECIALLY SINCE IT SLIGHTLY COLDER IN THE LOWER LEVELS OVR WRN UPR MI. SNOW SHOWERS WILL BEGIN TO DIMINISH LATE MONDAY IN THE WEST BUT LIKELY WILL FALL HEAVY AT TIMES INTO MONDAY NIGHT IN THE NCNTRL CWA. TUESDAY INTO TUESDAY NIGHT...CLIPPER SYSTEM SHOWN BY ALL GUIDANCE STILL ON TRACK BUT NOW ARRIVES QUICKER. GFS AND ECMWF INDICATE SIMILAR H85-H7 MOISTURE/WARM AIR ADVECTION/FRONTOGENESIS AND RESULTING QPF SLIDING INTO FAR WRN CWA BY 00Z WEDNESDAY THEN ACROSS REST OF CWA TUESDAY NIGHT. SFC LOW SETTLES OVR NRN LK HURON BY 00Z THURSDAY. GFS IS SLIGHTLY FARTHER SOUTH WITH TRACK OF SFC LOW AND UPR TROUGH THAN ECWMF. WILL CONTINUE TO KEEP HIGHEST POPS OVR NRN UPR MI ALONG TRACK OF UPR WAVE. LK EFFECT/ENHANCEMENT OFF LK MICHIGAN TUESDAY EVENING STILL A POSSIBILITY WITH SW LOW LEVEL WINDS AND H85 TEMPS BLO -10C. SINCE GREATEST H95 CONVERGENCE IS MAXIMIZED FOR JUST A BRIEF TIME (00Z-06Z ON WEDNESDAY) AND SNOW FM SYSTEM IS EXPECTED TO BE LESS THAN AN INCH...AREAS DOWNWIND OF LK MICHIGAN (GULLIVER TO NEWBERRY) COULD SEE AN INCH OR TWO...BUT NO SIGNIFICANT ACCUMS ARE ANTICIPATED. REINFORCING COLD FRONT DRIVES INTO CWA LATE WEDNESDAY...SO HAVE TRIMMED POPS FOR MUCH OF THE DAY. EVENTUALLY LK EFFECT WILL RAMP UP WEDNESDAY NIGHT AS H85/H7 TEMPS FALL TO -15C/-22C AND DEEPER MOISTURE/CYCLONIC FLOW LINGERS IN WAKE OF THE CLIPPER LOW. N/NW WIND SNOWBELTS FAVORED FOR THE MOST SNOW ACCUMULATION. HIGH POPS FOR LK EFFECT SNOWS REMAIN IN FCST THURSDAY INTO FRIDAY. ALTHOUGH IT REMAINS SUFFICIENTLY COLD ENOUGH FOR LES DURING THIS TIME...APPROACHING HIGH PRESSURE FM THE PLAINS AND BACKING LOW LEVEL FLOW SHOULD ALLOW DRIER AIR TO FILTER IN BENEATH THE LK EFFECT INVERSION. SO...SNOW SHOWERS SHOULD BE ON THE DOWNSWING BY NEXT FRIDAY AND PROBABLY COMPLETELY END BY NEXT SATURDAY. GIVEN THE UNCERTAINTY MENTIONED EARLIER FOR NEXT WEEKEND...PREFERRED HPC IDEA OF SLOWER DEVELOPMENT TO THE ZONAL FLOW PATTERN AND AS A RESULT KEPT THE SATURDAY FCST DRY AS SFC RIDGE FINISHES CROSSING THE REGION. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... AT KCMX...EXPECT MVFR CIGS TO PREVAIL THRU THIS FCST PERIOD UNDER CHILLY NW FLOW. ALTHOUGH THERE WILL BE SOME -SHSN FROM TIME TO TIME DURING THE NIGHT...CONDITIONS AREN`T FAVORABLE FOR ANY PERIODS OF PERSISTENT HEAVIER SHSN TO REDUCE VIS BLO VFR. WITH CONTINUED GRADUAL CAA AND AN INCREASE IN MOISTURE DEPTH SUNDAY WITH UPPER LEVEL DISTURBANCE...SHOULD SEE DEVELOPMENT OF PREVAILING MVFR VIS IN -SHSN AS ATMOSPHERE BECOMES MORE SUPPORTIVE OF LAKE EFFECT SNOW. WHILE THERE WILL PROBABLY BE SOME PERIODS OF VFR VIS AND PERHAPS IFR VIS AS WELL...THERE IS LITTLE CONFIDENCE IN PICKING OUT ANY TIME PERIODS FOR THOSE OCCURRENCES. AT KSAW...DOWNSLOPING NW FLOW SHOULD RESULT IN VFR CIGS PREVAILING DURING THE NIGHT. VFR CIGS SHOULD THEN GIVE WAY TO MVFR CIGS AND SOME FLURRIES (VFR VIS) DURING THE MORNING AS DEEPER MOISTURE AND UPPER LEVEL DISTURBANCE ARRIVE. EXPECT MVFR CIGS TO PREVAIL IN THE AFTN AND EVENING. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... EXPECT LOW PRESSURE TO EXIT THE GREAT LAKES LATE TODAY AND HEAD INTO CENTRAL QUEBEC BY SUNDAY NIGHT. N WINDS TO 30 KNOTS WITH CONSIDERABLE OVERWATER INSTABILITY WILL DIMINISH AND BACK NW LATER TONIGHT AS THE LOW SHIFTS TO THE EAST. HIGH PRESSURE WILL MOVE INTO THE CANADIAN PRAIRIES SUNDAY EVENING AND INTO THE NORTHERN PLAINS MONDAY MORNING...DOMINATING THE UPPER MISSISSIPPI RIVER VALLEY THROUGH TUESDAY. THEN LOW PRESSURE NORTHWEST OF LAKE WINNIPEG TUESDAY MORNING WILL PULL A TROUGH ACROSS LAKE SUPERIOR ON WEDNESDAY. HIGH PRESSURE WILL MOVE SOUTHEASTWARD FROM LAKE WINNIPEG TO THE NORTHERN PLAINS ON THURSDAY. EXPECT N GALES ON WED INTO THU OVER CENTRAL AND EASTERN LAKE SUPERIOR IN THE SHARP PRESSURE GRADIENT BETWEEN THE DEPARTING TROUGH AND INCOMING HIGH PRESSURE CENTER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WATCH SUN EVENING THRU MON EVENING MIZ005-006. LAKE EFFECT SNOW WARNING 3 AM TO 7 PM EST SUN MIZ006-085. LAKE EFFECT SNOW ADVY 3 AM TO 7 PM EST SUN MIZ014. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SYNOPSIS...KC SHORT TERM...KC LONG TERM...JLA AVIATION...ROLFSON MARINE...KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 557 PM CST MON NOV 17 2008 .UPDATE... UPDATED FOR AVIATION DISCUSSION BELOW. && .DISCUSSION... /ISSUED 300 PM CST MON NOV 17 2008/ VISIBLE SATELLITE IMAGERY BEGINNING TO SIGNS OF ABUNDANT CU/SC IN COLD UNSTABLE AIR DISSIPATING. WILL CONTINUE WITH THE MENTION OF SCATTERED FLURYS NE AREAS UNTIL AROUND 8 PM. IN THE OVERNIGHT HOURS CWA WILL BE ENTRENCHED IN COLD CANADIAN HIGH PRESSURE WITH CLEARING SKIES AND CHILLY TEMPERATURES. AFTER A COLD START WARM ADVECTION AHEAD OF NEXT LOW PRESSURE WILL BUMP UP TEMPERATURES A BIT FROM LEVELS OF TODAY. THIS SYSTEM SHOULD AFFECT MAINLY AREAS TO OUR NORTH WITH SOME LIGHT PRECIPITATION. LOOKING AT SEVERAL ISENTROPIC SURFACES AIRMASS LOOKS PRETTY DRY EXCEPT FOR SHALLOW LAYER NEAR SURFACE. TRIMMED BACK THE AREA OF -SW A BIT AND ADDED THREAT OF PATCHY -ZL...THIS SHOULD AFFECT ONLY SMALL PART OF EC MN INTO WI. LOW LEVEL WINDS APPEAR TO STRONG FOR FOG...SO REMOVED FOG THREAT FROM SW MN. SORT OF A PUSH-PULL PATTERN IN TEMPERATURE DEPARTMENT FOR THE NEXT WEEK OR SO WITH GENERALLY NWLY FLOW INTERRUPTED BY A COUPLE OF LOW PRESSURE SYSTEMS DROPPING OUT OF NW CANADA ACROSS N MN OR NW ONTARIO. WILL SEE A BIT OF A WARMUP TOMORROW INTO WEDNESDAY AND THEN AGAIN INTO THE WEEKEND. DRY NORTHWEST FLOW DOESN`T SUPPORT MUCH IN THE WAY OF PRECIPITATION OTHER THAN -SW AS SURGES OF COLDER AIR COME THRU. && .AVIATION.../00Z TAF ISSUANCE/ SC SLOWLY DISSIPATING THIS EVENING FOR THE MN TAF SITES. STILL A HEALTHY AREA OF CLOUDS AND FLURRIES STREAMING INTO NWRN WISC SO WILL HOLD ON TO BKN CLOUDS IN THE 4K-5K RANGE INTO THE LATE EVENING... ALONG WITH SNOW SHOWERS BUT VSBYS ABOVE 6SM. RUC STREAMLINES IN THE LOW LEVELS STILL SHOW A BIT OF CYCLONIC CURVATURE THIS EVENING. WITH NEXT WAVE... HIGH AND THEN MID CLOUDS WILL SPREAD ACROSS THE REGION LATE TONIGHT IN WRN MN AND REST OF AREA TOMORROW...ALONG WITH STRENGTHENING SOUTH WINDS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ BAP/TDK mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 744 AM CST MON NOV 17 2008 .UPDATE...HAVE UPDATED MUCH OF NE MN ZONES/GRIDS TO INCREASE POPS TO LIKELY CATEGORY. HAVE ALSO ADDED 1 TO 2 INCH SNOWFALL AMOUNTS DUE TO RATHER ROBUST BANDS OF SNOW ORIENTED IN THE NW FLOW...AND AHEAD OF THE INCOMING VORT MAX. A FEW PLACES SAW ABOUT AN INCH OF SNOW OVERNIGHT. TRAINING OF THESE BANDS MAY RESULT IN LOCAL 1 TO 2 INCHES OF ADDITIONAL SNOWFALL. SNOW BANDS CONTINUE TO MOVE ONSHORE ALONG THE SOUTH SHORE...WITH 5 INCHES AT LAST CHECK IN GILE. THE BEST FORCING WILL BE DEVELOPING THIS MORNING...INTO THE AFTERNOON. CONFIDENCE IS INCREASING THAT THE GOGEBIC RANGE WILL SEE 7 TO 11 INCHES OF TOTAL ACCUMULATION...AND IF A SINGULAR FOCUSED BAND DOES DEVELOP OFF THE TIP OF THE PENINSULA...A LOCALIZED LOCATION COULD SEE A FOOT OR MORE. WILL CONTINUE TO MONITOR IN THE EVENT WE NEED TO INCREASE AMOUNTS. && .PREV DISCUSSION... /ISSUED 405 AM CST MON NOV 17 2008/ DISCUSSION...MAIN FOCUS FOR TODAY IS POTENTIAL FOR HEAVY LAKE EFFECT SNOW ON THE SOUTH SHORE. SCATTERED SNOW SHOWERS CONTINUE TO MOVE THROUGH THE CWA THIS EARLY MORNING IN ASSOCIATION WITH A WEAK WAVE NOT HANDLED WELL BY OPERATIONAL MODELS. SOME OF THE SNOW SHOWERS HAD DROPPED VSBYS TO AROUND 2 MILES. BANDS OF LAKE EFFECT/ENHANCED SNOW HAD DEVELOPED DURING THE NIGHT...WITH KDLH 88D SHOWING TOPS AROUND 10K FT. THE SNOW BANDS DID TAKE A WHILE TO GET GOING...MAINLY DUE TO SOME LOW LEVEL DRY AIR AND DOWNWARD MOTION/SUBSIDENCE FOR A TIME. THE LATEST GUIDANCE STILL LOOKING IMPRESSIVE FOR THE POTENTIAL FOR LAKE EFFECT TO CONTINUE TODAY...WITH THE MOST FAVORABLE CONDITIONS EXPECTED TO DEVELOP THIS MORNING AND CONTINUE INTO THIS AFTERNOON. WATER VAPOR IMAGERY SHOWS A RATHER ROBUST SHORTWAVE/VORTMAX DROPPING SOUTHWARD THROUGH NW ONTARIO. THE RUC HAS THE VORT MAX ROTATING THROUGH NE MN AND INTO NW WI DURING THE DAY...BRINGING ENHANCED UPWARD VERTICAL MOTION AND FIRMLY ESTABLISHING LAKE SNOW BANDS. THIS SETUP IS ALSO FAVORABLE FOR THE DEVELOPMENT OF A DOMINANT BAND FOCUSING OFF THE TIP OF THE BAYFIELD PENINSULA... WHICH COULD RESULT IN SOME SNOW SQUALLS WITH RATES OF AN INCH AN HOUR OR SO AT SOME POINT THIS MORNING/AFTERNOON. FAVORABLE INVERSION HEIGHTS...DELTA-T VALUES AND LITTLE SHEAR SHOULD ALL CONTRIBUTE TO A FAVORABLE ENVIRONMENT FOR LAKE EFFECT. WILL LIKELY INCREASE SNOW AMOUNTS A BIT ALONG THE GOGEBIC RANGE. FURTHER WEST...THE POTENTIAL FOR SIGNIFICANT ACCUMULATION IS A LITTLE LESS CERTAIN. WHILE CROSS SECTIONS DO INDICATE THE POTENTIAL FOR A STANDING WAVE/GRAVITY WAVE INDUCED BAND IN DOUGLAS/BAYFIELD COUNTY...THEY TEND TO DO BEST WHEN THERE HAS BEEN BACKING WINDS FROM THE NE TO NW AFTER A DEPARTING SYSTEM MOVES EAST OF THE AREA. DESPITE THIS...THINK SOME ACCUMULATION WILL BE POSSIBLE DUE TO ENHANCED UVM FROM THE SHORTWAVE AND POTENTIAL FOR SHORT FETCH SNOW BANDS DUE TO FAVORABLE LAKE-H85 DELTA-T VALUES EVEN IF THE GRAVITY WAVE FEATURE DOES NOT DEVELOP. WILL LEAVE ADVISORY AS IS FOR NOW. THE SNOW SHOWERS WILL GRADUALLY DIMINISH TONIGHT...BUT SOME LIGHTER ACCUMULATION WILL STILL BE POSSIBLE FOR A TIME. THE REST OF THE AREA SHOULD SEE CLOUDS BREAK UP FROM WEST TO EAST FROM THIS AFTERNOON THROUGH TONIGHT. WILL GO WITH SCATTERED SNOW SHOWERS MOST AREAS TODAY DUE TO THE STRONG VORT MAX DROPPING THROUGH THE CWA. SKIES SHOULD BECOME PARTLY CLOUDY TONIGHT...WITH STRONG WAA AHEAD OF THE NEXT FEATURE BRINGING SOME INCREASE IN CLOUDS AGAIN ON TUESDAY AND TUESDAY NIGHT. COULD BE SOME LIGHT SNOW... ESPECIALLY NORTH ON TUESDAY NIGHT. WED THRU FRIDAY...OVERALL PATTERN FEATURES FAST WNW MID LVL FLOW WITH 50H HEIGHTS SLIGHTLY ABOVE NORMAL.ALTHOUGH NEGATIVE 85H TEMP ANOMALIES BEGIN TO MODIFY...TWO CONSECUTIVE LARGE SFC HIGHS WILL MAINTAIN CHILLY READINGS THROUGH PERIOD. IN TERMS OF SENSIBLE WX...INITIAL ISENTROPIC LIFT WILL ACCOMPANY SHORTWAVE COMING OVER RIDGE TUESDAY NIGHT/WED. BIG QUESTION IS WHETHER WE GET JUST CLOUDS OR PRECIP AS WELL. WILL NEED TO BE VIGILANT WITH THIS AS DESPITE LOW POPS OVER SRN CWA...MDL SNDGS SUGGEST SUPERCOOLED WATER AS MAIN HYDROMETEOR. WITH SFC TEMPS BELOW FREEZING SOME FR RAIN MAY DEVELOP NEAR BRD LAKES REGION AND EAST TO PINE COUNTY. OVER NRN CWA WHERE ENOUGH ASCENT OCCURS FOR SATURATION...SHOULD SEE SNOW..POSSIBLY SOME SLEET ON SRN FRINGE OF PRECIP AREA. SECONDARY SURGE OF POLAR AIR ADVECTS SOUTH WED WITH SNSH INCREASING OVER NRN CWA AND IN LES OF WISC...ESPECIALLY WED NIGHT...TAPERING THURSDAY. MDLS DIVERGE SIGNIFICANTLY BY FRIDAY WITH GFS OUT OF SORTS WITH ITS ENSEMBLE MEMBERS AND EC FLIP FLOPPING FROM LAST RUN. WILL LEAVE DRY FOR NOW. AVIATION...A SHORTWAVE TROUGH WILL SWING SOUTH OUT OF CANADA THIS MORNING. AS A RESULT...TEMPO SCT SNOW SHOWERS WILL INTERMITTENTLY REDUCE VSBYS AND LOWER CIGS TO THE MVFR RANGE. OTW...WINDS WILL STRENGTHEN AND BECOME GUSTY OUT OF THE NW IN THE WAKE OF THE UPPER WAVE PASSAGE MON MORNING. SKIES WILL BECOME SCT TOWARDS THE END OF THE TAF PD...AND WINDS BECOME LIGHT...AS HIGH PRES BUILDS IN. && POINT TEMPS/POPS... DLH 26 8 28 19 / 60 10 10 20 INL 24 2 26 18 / 60 10 10 30 BRD 27 10 31 23 / 20 10 10 10 HYR 26 7 28 18 / 40 10 10 10 ASX 26 9 29 20 / 60 20 10 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND-IRON. LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BAYFIELD-DOUGLAS. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ146. SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LSZ121- LSZ147-LSZ148. $$ DAP/CANNON mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 405 AM CST MON NOV 17 2008 .DISCUSSION...MAIN FOCUS FOR TODAY IS POTENTIAL FOR HEAVY LAKE EFFECT SNOW ON THE SOUTH SHORE. SCATTERED SNOW SHOWERS CONTINUE TO MOVE THROUGH THE CWA THIS EARLY MORNING IN ASSOCIATION WITH A WEAK WAVE NOT HANDLED WELL BY OPERATIONAL MODELS. SOME OF THE SNOW SHOWERS HAD DROPPED VSBYS TO AROUND 2 MILES. BANDS OF LAKE EFFECT/ENHANCED SNOW HAD DEVELOPED DURING THE NIGHT...WITH KDLH 88D SHOWING TOPS AROUND 10K FT. THE SNOW BANDS DID TAKE A WHILE TO GET GOING...MAINLY DUE TO SOME LOW LEVEL DRY AIR AND DOWNWARD MOTION/SUBSIDENCE FOR A TIME. THE LATEST GUIDANCE STILL LOOKING IMPRESSIVE FOR THE POTENTIAL FOR LAKE EFFECT TO CONTINUE TODAY...WITH THE MOST FAVORABLE CONDITIONS EXPECTED TO DEVELOP THIS MORNING AND CONTINUE INTO THIS AFTERNOON. WATER VAPOR IMAGERY SHOWS A RATHER ROBUST SHORTWAVE/VORTMAX DROPPING SOUTHWARD THROUGH NW ONTARIO. THE RUC HAS THE VORT MAX ROTATING THROUGH NE MN AND INTO NW WI DURING THE DAY...BRINGING ENHANCED UPWARD VERTICAL MOTION AND FIRMLY ESTABLISHING LAKE SNOW BANDS. THIS SETUP IS ALSO FAVORABLE FOR THE DEVELOPMENT OF A DOMINANT BAND FOCUSING OFF THE TIP OF THE BAYFIELD PENINSULA... WHICH COULD RESULT IN SOME SNOW SQUALLS WITH RATES OF AN INCH AN HOUR OR SO AT SOME POINT THIS MORNING/AFTERNOON. FAVORABLE INVERSION HEIGHTS...DELTA-T VALUES AND LITTLE SHEAR SHOULD ALL CONTRIBUTE TO A FAVORABLE ENVIRONMENT FOR LAKE EFFECT. WILL LIKELY INCREASE SNOW AMOUNTS A BIT ALONG THE GOGEBIC RANGE. FURTHER WEST...THE POTENTIAL FOR SIGNIFICANT ACCUMULATION IS A LITTLE LESS CERTAIN. WHILE CROSS SECTIONS DO INDICATE THE POTENTIAL FOR A STANDING WAVE/GRAVITY WAVE INDUCED BAND IN DOUGLAS/BAYFIELD COUNTY...THEY TEND TO DO BEST WHEN THERE HAS BEEN BACKING WINDS FROM THE NE TO NW AFTER A DEPARTING SYSTEM MOVES EAST OF THE AREA. DESPITE THIS...THINK SOME ACCUMULATION WILL BE POSSIBLE DUE TO ENHANCED UVM FROM THE SHORTWAVE AND POTENTIAL FOR SHORT FETCH SNOW BANDS DUE TO FAVORABLE LAKE-H85 DELTA-T VALUES EVEN IF THE GRAVITY WAVE FEATURE DOES NOT DEVELOP. WILL LEAVE ADVISORY AS IS FOR NOW. THE SNOW SHOWERS WILL GRADUALLY DIMINISH TONIGHT...BUT SOME LIGHTER ACCUMULATION WILL STILL BE POSSIBLE FOR A TIME. THE REST OF THE AREA SHOULD SEE CLOUDS BREAK UP FROM WEST TO EAST FROM THIS AFTERNOON THROUGH TONIGHT. WILL GO WITH SCATTERED SNOW SHOWERS MOST AREAS TODAY DUE TO THE STRONG VORT MAX DROPPING THROUGH THE CWA. SKIES SHOULD BECOME PARTLY CLOUDY TONIGHT...WITH STRONG WAA AHEAD OF THE NEXT FEATURE BRINGING SOME INCREASE IN CLOUDS AGAIN ON TUESDAY AND TUESDAY NIGHT. COULD BE SOME LIGHT SNOW... ESPECIALLY NORTH ON TUESDAY NIGHT. WED THRU FRIDAY...OVERALL PATTERN FEATURES FAST WNW MID LVL FLOW WITH 50H HEIGHTS SLIGHTLY ABOVE NORMAL.ALTHOUGH NEGATIVE 85H TEMP ANOMALIES BEGIN TO MODIFY...TWO CONSECUTIVE LARGE SFC HIGHS WILL MAINTAIN CHILLY READINGS THROUGH PERIOD. IN TERMS OF SENSIBLE WX...INITIAL ISENTROPIC LIFT WILL ACCOMPANY SHORTWAVE COMING OVER RIDGE TUESDAY NIGHT/WED. BIG QUESTION IS WHETHER WE GET JUST CLOUDS OR PRECIP AS WELL. WILL NEED TO BE VIGILANT WITH THIS AS DESPITE LOW POPS OVER SRN CWA...MDL SNDGS SUGGEST SUPERCOOLED WATER AS MAIN HYDROMETEOR. WITH SFC TEMPS BELOW FREEZING SOME FR RAIN MAY DEVELOP NEAR BRD LAKES REGION AND EAST TO PINE COUNTY. OVER NRN CWA WHERE ENOUGH ASCENT OCCURS FOR SATURATION...SHOULD SEE SNOW..POSSIBLY SOME SLEET ON SRN FRINGE OF PRECIP AREA. SECONDARY SURGE OF POLAR AIR ADVECTS SOUTH WED WITH SNSH INCREASING OVER NRN CWA AND IN LES OF WISC...ESPECIALLY WED NIGHT...TAPERING THURSDAY. MDLS DIVERGE SIGNIFICANTLY BY FRIDAY WITH GFS OUT OF SORTS WITH ITS ENSEMBLE MEMBERS AND EC FLIP FLOPPING FROM LAST RUN. WILL LEAVE DRY FOR NOW. && .AVIATION...A SHORTWAVE TROUGH WILL SWING SOUTH OUT OF CANADA THIS MORNING. AS A RESULT...TEMPO SCT SNOW SHOWERS WILL INTERMITTENTLY REDUCE VSBYS AND LOWER CIGS TO THE MVFR RANGE. OTW...WINDS WILL STRENGTHEN AND BECOME GUSTY OUT OF THE NW IN THE WAKE OF THE UPPER WAVE PASSAGE MON MORNING. SKIES WILL BECOME SCT TOWARDS THE END OF THE TAF PD...AND WINDS BECOME LIGHT...AS HIGH PRES BUILDS IN. && POINT TEMPS/POPS... DLH 26 8 28 19 / 40 10 10 20 INL 24 2 26 18 / 40 10 10 30 BRD 27 10 31 23 / 20 10 10 10 HYR 26 7 28 18 / 40 10 10 10 ASX 26 9 29 20 / 60 20 10 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...LAKE EFFECT SNOW WARNING UNTIL 6 PM CST THIS AFTERNOON FOR ASHLAND-IRON. LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR BAYFIELD-DOUGLAS. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CST THIS AFTERNOON FOR LSZ146. SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LSZ121- LSZ147-LSZ148. $$ DAP/CANNON mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 205 PM CST SUN NOV 16 2008 .DISCUSSION... OVERALL... THE WEATHER WILL REMAIN FAIRLY BENIGN THROUGH THE FORECAST PERIOD. THE MAIN SHORT TERM CONCERNS ARE THE CLOUD COVER CURRENTLY OVER MUCH OF THE AREA... ALONG WITH SOME SCATTERED FLURRIES... AND THE CHANCES FOR SOME ADDITIONAL SNOW SHOWER ACTIVITY MONDAY AS ANOTHER SHORTWAVE SWINGS THROUGH THE AREA. THE 12Z NAM AND GFS ARE REASONABLY SIMILAR IN THEIR HANDLING OF THINGS THROUGH THE SHORT TERM... ALTHOUGH DIFFERENCES START TO BECOME MORE PRONOUNCED BY THE TUE-WED TIME FRAME. UTILIZED A BLEND OF THEIR GUIDANCE THROUGH MONDAY... THEN TRENDED MORE TOWARD THE SREF AND ECMWF BY THE TUE-WED TIME FRAME WHEN WARM ADVECTION AND FORCING WITH THE NEXT SHORTWAVE OF ANY SIGNIFICANT MOVES THROUGH THE AREA. IT WILL BE DIFFICULT TO GET RID OF THE LOW CLOUDS OVER THE AREA UNTIL THE LOW LEVEL RIDGE AXIS AND ASSOCIATED DRIER BOUNDARY LAYER AIR AND ANTICYCLONIC FLOW ARRIVE... WHICH DOESN/T HAPPEN IN EARNEST UNTIL MONDAY AFTERNOON AND EVENING... FROM WEST TO EAST ACROSS THE AREA. OTHER THAN THE PRESENCE OF DECENT BOUNDARY LAYER LAPSE RATES AND CYCLONIC FLOW... THERE ISN/T MUCH IN THE WAY OF FORCING FOR SNOW SHOWER ACTIVITY TONIGHT. HOWEVER... GIVEN UPSTREAM OBS AND THE AFOREMENTIONED THERMODYNAMIC FACTORS... WILL RETAIN A MENTION OF SOME LOW CHANCES FOR SNOW SHOWER AND FLURRIES OVER THE NORTHEAST TWO-THIRDS OR SO OF THE AREA FOR TONIGHT. BY LATE TONIGHT... AND MORE-SO MONDAY MORNING INTO EARLY AFTERNOON... THERE WILL BE AN INCREASE IN FORCING AS THE SHORTWAVE FEATURE CURRENTLY DROPPING SOUTHEAST THROUGH MANITOBA SWINGS THROUGH NORTHEAST MINNESOTA AND ACROSS WISCONSIN. THE NAM AND GFS BOTH SUGGEST SOME MODEST 850-500MB Q-VECTOR CONVERGENCE WITH THIS FEATURE... WHICH SHOULD INTERACT WITH THE LINGERING 925-700MB MOISTURE TO ENHANCE THE SNOW SHOWERS FOR A TIME OVER WEST CENTRAL WISCONSIN ON MONDAY. DO NOT EXPECT MUCH IF ANYTHING IN THE WAY OF ACCUMULATIONS GIVEN THE OVERALL PAUCITY OF MOISTURE AND THE QUICK MOVING NATURE OF THE SHORTWAVE... BUT WOULD EXPECT THE SNOW SHOWERS TO BECOME A BIT MORE ROBUST IN THAT AREA FOR A PORTION OF THE MORNING AND EARLY AFTERNOON. HIGH PRESSURE WILL SETTLE ACROSS THE REGION MONDAY NIGHT INTO TUESDAY MORNING. HOWEVER... WARM ADVECTION IN THE BOUNDARY LAYER WILL RETURN TO MUCH OF THE AREA BY TUESDAY AFTERNOON. WARM ADVECTION ACTUALLY INCREASES EVEN EARLIER IN THE 700-500MB LAYER... DEVELOPING OVER THE WESTERN CWFA BY 12Z. VIGOROUS WARM ADVECTION IS ADVERTISED BY THE NAM... GFS... AND SREF... BUT ALL OF THE GUIDANCE INDICATES THAT THE LIFT AND MOISTURE WILL BE OUT OF PHASE... WITH VERY LITTLE ALIGNMENT OF THE LOW-LEVEL LIFT/MOISTURE WITH THE MID-LEVEL ACTIVITY... SUGGESTING WE WILL PRIMARILY JUST SEE IN INCREASE IN MID-HIGH CLOUDS... FOLLOWED BY INCREASING LOWER CLOUDS DURING THE AFTERNOON AND INTO TUESDAY NIGHT. A LOOK AT THE 290K AND 295K SURFACES SUPPORTS THIS AS WELL... SHOWING VERY LITTLE ALIGNMENT OF THE LOWER CONDENSATION PRESSURE DEFICIT VALUES ON THE TWO SURFACES. IN ADDITION... A LOOK AT THE NET ADIABATIC ISENTROPIC OMEGA PROGS SUGGESTS THAT THE PRESSURE ADVECTION... WHICH IS VIGOROUS GIVEN THE TIGHTLY PACKED PRESSURE SURFACES AND DECENT WINDS... IS OFFSET TO LARGE DEGREE BY THE DESCENT OF THE PRESSURE SURFACES THEMSELVES... WHICH OCCURS QUITE QUICKLY. THE NET RESULT IS FAIRLY WEAK NET ADIABATIC ISENTROPIC OMEGA VALUES OF 1-2 MICROBARS/SECOND AS THIS FEATURE SWINGS THROUGH OUR AREA. THE FORCING AND MOISTURE ALIGN SOMEWHAT BETTER FARTHER TO THE NORTH... KEEPING CHANCES OF MEASURABLE PCPN OUT OF OUR AREA. HOWEVER... GIVEN THE RAPID INCREASE IN TEMPERATURES AND A DECENT INCREASE IN ABSOLUTE HUMIDITY... PW RISING FROM AROUND .15 INCHES TO .5 INCHES / 40 PCT OR NORMAL TO 150 PCT OF NORMAL... CAN/T ENTIRELY RULE OUT SOMETHING MAKING IT TO THE GROUND IN OUR AREA. THE WET BULB PROFILES WOULD SUPPORT AN ENTIRELY SUB-FREEZING SOUNDING AS THINGS MOVE THROUGH... SO WILL INCLUDE SOME MENTION OF FLURRIES OVER THE NORTHERN AND EASTERN PORTIONS OF THE AREA TUESDAY INTO TUESDAY NIGHT. THE SURFACE LOW/TROUGH WILL BE OVER MINNESOTA WEDNESDAY MORNING... AND NEAR LAKE MICHIGAN BY EVENING. VERY LITTLE QG FORCING IS SUGGESTED ALONG THE SURFACE TROUGH... WITH ALL OF THE ACTION ASSOCIATED WITH THE ZONE OF WARM ADVECTION WHICH WILL BE THROUGH THE AREA AND SOME MID-LEVEL DEFORMATION AND UPPER LEVEL DIVERGENCE WHICH WILL BE TO OUR NORTH. SO... WILL GO WITH DRY WEATHER ON WEDNESDAY. THE EXTENDED PERIOD... THURSDAY THROUGH SUNDAY... LOOKS ABOUT AS QUIET AS ONE COULD EXPECT FOR THIS TIME OF YEAR. THE 00Z ECMWF AND GFS AREN/T IN HORRIBLE DISAGREEMENT WITH LONG WAVE FEATURES... BUT THERE IS CERTAINLY SOME DISAGREEMENT ON THE AMPLITUDE AND POSITION OF EMBEDDED SHORTWAVES AND THEIR ASSOCIATED SURFACE FEATURES. GENERALLY PREFERRED THE ECMWF SOLUTION... WHICH IS SUPPORTED BY THE 00Z CANADIAN... AND MATCHES UP WELL WITH HPC MANUAL PROGS. THIS SUPPORTS SOME DEAMPLIFICATION OF THE UPPER PATTERN OVER NORTH AMERICAN THROUGH THE PERIOD... WITH PRONOUNCED TROUGHS OFF THE WEST COAST AND OVER EASTERN CANADA/NORTHEAST CONUS ON THURSDAY GIVING WAY TO MORE OF A ZONAL PATTERN ALONG THE US/CANADA BORDER BY SUNDAY... WITH THE MAIN UPPER LOWS/TROUGHS PUSHED BACK TOWARD WESTERN ALASKA AND NORTH OF HUDSON BAY. THE HPC TIMING OF SURFACE HIGHS/LOWS/FRONTS MATCHES UP QUITE WELL WITH A BLEND OF THE 00Z ECMWF AND CANADIAN MODELS... AND GENERALLY TIED WEATHER TO THOSE FEATURES AND THEIR ASSOCIATED SHORTWAVES. ALL OF THIS EQUATES TO A DRY FORECAST OVER THE AREA FOR THE ENTIRE PERIOD... WITH NO MAJOR DEPARTURES FROM NORMAL IN THE TEMPERATURE DEPARTMENT. READINGS MAY BE A BIT COOLER THAN NORMAL IN THE THU-FRI TIME FRAME... BUT COULD MODERATE AND BE A BIT WARMER THAN NORMAL SAT-SUN. THERE ARE TWO POTENTIAL FEATURES OF INTEREST WHICH COULD EVENTUALLY INTRODUCE SOME CHANCE FOR PCPN INTO THE FORECAST... BUT NEITHER LOOKS SIGNIFICANT AT THIS POINT IN TIME. WARM ADVECTION ARRIVES FRIDAY NIGHT INTO SATURDAY AHEAD OF A SHORTWAVE AND FRONTAL BOUNDARY WHICH WILL MOVE THROUGH ON SATURDAY. HOWEVER... THE SURFACE LOW POSITION IS PROGGED SUFFICIENTLY NORTH TO KEEP ANY SATURATION... ALONG WITH THE BETTER FORCING... NORTH OF OUR AREA. BY LATE SUNDAY... A SHORTWAVE AND SURFACE LOW ARE SHOWN TO LIFT NORTHEAST FROM THE SOUTHERN ROCKIES TOWARD THE LOWER MISSISSIPPI VALLEY. THIS SYSTEM COULD EVENTUALLY BRING SOME PCPN CHANCES INTO THE SOUTHERN CWFA... BUT THE CURRENT TIMING WOULDN/T DO SO UNTIL SUNDAY NIGHT OR MONDAY. && .AVIATION... /18Z TAF ISSUANCE/ LOW PRESSURE NEAR WATERLOO LATE THIS MORNING WITH FRONTAL BOUNDARY TRAILING NORTHWEST ALONG THE MN RIVER VALLEY. BANDS OF LIGHT SNOW LINGER FROM LITTLE FALLS AND MORA TO RED WING AND EAU CLAIRE. THIS LINES UP WELL WITH THE MID LEVEL FRONTOGENESIS. THE RUC/NAM BOTH SHOW DIMINISHING FRONTOGENESIS THIS AFTERNOON WITH THE BANDS DISSOLVING. CEILINGS CURRENTLY VFR EXCEPT AT KRNH AND KRWF WITH SCATTERED HOLES IN THE CLOUD DECK ACROSS THE FA. QUITE A CHALLENGE WITH CEILINGS BUT EXPECT BKN-OVC MVFR CONDITIONS TO DEVELOP AS THE AFTERNOON PROGRESSES ALONG WITH SOME FLURRIES OR SNOW SHOWERS. INDICATIONS ARE FOR LOW MVFR (010-015) CEILINGS TO DEVELOP/SPREAD IN FROM THE NORTH TONIGHT AS A CANADIAN COLD FRONT PUSHES SOUTH. LOWERED CEILINGS OVERNIGHT ALONG WITH INCREASING NORTHWEST WIND. A BRISK NORTHWEST WINDS ON MONDAY ALONG WITH A CONTINUATION OF BKN-OVC MVFR CEILINGS. IMPROVEMENT EXPECTED IN THE AFTERNOON OVER WESTERN MN AS THE 850MB RIDGE AXIS GET CLOSER. INCLUDED FROM CWSU ZMP... INTERESTING SETUP GOING ON WITH TWO BANDS NW-SE ORIENTED NEARBY. BOTH CONTAIN IFR CONDITIONS ONE TO OUR EAST IS BARELY EAST OF US AND THE OTHER IW SOME 80 NM WEST OF US. GENERAL FLOW IS OUT OF THE NW AND SOMETIME IT APPEARS THAT IT WILL HIT MSP INTO THIS AFTN. THE ONE TO THE EAST OF US HAS SOME SNOW FALLING IN IT AND THIS ONE HAS CAUSED SOME SNOWFALL AT MSP FOR THE LAST HOUR. ON THE OTHERHAND WITH TIME WIND WILL BECOME ESTABLISHED SOON OUT OF THE NW FOR THE REST OF THE DAY AND INTO MONDAY. LATELY IT HAS BEEN NE AND LIGHT IN INTENSITY. BEST WAY TO GET TO THE NW IS THRU THE NORTH DIRECTION AND IT SHUD TAKE PLACE SHORTLY. WITH THE WIND CHANGE THE MVFR CIGS SHUD BE CLOSE ENUF TO MSP TO GIVE THAT POSSIBILITY INTO THIS AFTN ALONG WITH SOME PSBL LGT SNOW. OVERALL THE WX SHUD SLOWLY IMPROVE WITH CIGS AND VIS INTO THE NITE AND MONDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ TRH/RAH/HP mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1144 AM CST SUN NOV 16 2008 .AVIATION... /18Z TAF ISSUANCE/ LOW PRESSURE NEAR WATERLOO LATE THIS MORNING WITH FRONTAL BOUNDARY TRAILING NORTHWEST ALONG THE MN RIVER VALLEY. BANDS OF LIGHT SNOW LINGER FROM LITTLE FALLS AND MORA TO RED WING AND EAU CLAIRE. THIS LINES UP WELL WITH THE MID LEVEL FRONTOGENESIS. THE RUC/NAM BOTH SHOW DIMINISHING FRONTOGENESIS THIS AFTERNOON WITH THE BANDS DISSOLVING. CEILINGS CURRENTLY VFR EXCEPT AT KRNH AND KRWF WITH SCATTERED HOLES IN THE CLOUD DECK ACROSS THE FA. QUITE A CHALLENGE WITH CEILINGS BUT EXPECT BKN-OVC MVFR CONDITIONS TO DEVELOP AS THE AFTERNOON PROGRESSES ALONG WITH SOME FLURRIES OR SNOW SHOWERS. INDICATIONS ARE FOR LOW MVFR (010-015) CEILINGS TO DEVELOP/SPREAD IN FROM THE NORTH TONIGHT AS A CANADIAN COLD FRONT PUSHES SOUTH. LOWERED CEILINGS OVERNIGHT ALONG WITH INCREASING NORTHWEST WIND. A BRISK NORTHWEST WINDS ON MONDAY ALONG WITH A CONTINUATION OF BKN-OVC MVFR CEILINGS. IMPROVEMENT EXPECTED IN THE AFTERNOON OVER WESTERN MN AS THE 850MB RIDGE AXIS GET CLOSER. INCLUDED FROM CWSU ZMP... INTERESTING SETUP GOING ON WITH TWO BANDS NW-SE ORIENTED NEARBY. BOTH CONTAIN IFR CONDITIONS ONE TO OUR EAST IS BARELY EAST OF US AND THE OTHER IW SOME 80 NM WEST OF US. GENERAL FLOW IS OUT OF THE NW AND SOMETIME IT APPEARS THAT IT WILL HIT MSP INTO THIS AFTN. THE ONE TO THE EAST OF US HAS SOME SNOW FALLING IN IT AND THIS ONE HAS CAUSED SOME SNOWFALL AT MSP FOR THE LAST HOUR. ON THE OTHERHAND WITH TIME WIND WILL BECOME ESTABLISHED SOON OUT OF THE NW FOR THE REST OF THE DAY AND INTO MONDAY. LATELY IT HAS BEEN NE AND LIGHT IN INTENSITY. BEST WAY TO GET TO THE NW IS THRU THE NORTH DIRECTION AND IT SHUD TAKE PLACE SHORTLY. WITH THE WIND CHANGE THE MVFR CIGS SHUD BE CLOSE ENUF TO MSP TO GIVE THAT POSSIBILITY INTO THIS AFTN ALONG WITH SOME PSBL LGT SNOW. OVERALL THE WX SHUD SLOWLY IMPROVE WITH CIGS AND VIS INTO THE NITE AND MONDAY. .DISCUSSION... DEEP LONGWAVE TROUGH NOW ESTABLISHED FROM HUDSON BAY THROUGH THE LOWER GREAT LAKES AND INTO THE SOUTHEAST U.S. UPPER LEVEL HIGH WHICH HAS BEEN PARKED OFF THE CALIFORNIA COAST NOW MAKING SOME EASTWARD PROGRESS TOWARDS THE WEST COAST. THE PATTERN WILL PROGRESS EASTWARD THROUGH THE WEEK WITH UPPER TROUGH CONTINUING TO ROTATE OVER HUDSON BAY WHILE THE SOUTHERN PORTION OF THE TROUGH PIVOTS NORTHEASTWARD OFF THE ATLANTIC COAST THROUGH MIDWEEK. THE UPPER HIGH WILL WORK TOWARDS THE FOUR CORNERS BY MIDWEEK AS WELL. THE UPPER FLOW WILL FLATTEN OVERHEAD BUT REMAIN NORTHWESTERLY AND TRY TO TRANSITION TO WESTERLY THEN SOUTHWESTERLY NEXT WEEKEND. THE FIRST IN A SERIES OF SHORTWAVES APPEARS IN EARLY MORNING WATER VAPOR IMAGERY CROSSING NORTHERN MINNESOTA IN THE FAST NORTHWEST FLOW OVERHEAD. ANOTHER WILL APPROACH MIDWEEK. THIS WILL BRING A BIT OF A ROLLER COASTER RIDE TEMPERATURE WISE THROUGH THE FORECAST PERIOD AS COLD AIR SPILLS IN BEHIND EACH TROUGH AND WARM ADVECTION SPREADS IN AHEAD. ALBERTA CLIPPER IN THE PROCESS OF CROSSING THE CWA THIS MORNING. OCCLUDING SFC LOW IS OVER SOUTHEAST NORTH DAKOTA AT 09Z WITH WARM FRONT EXTENDING FROM NORTH TO SOUTH ACROSS SOUTHEASTERN SOUTH DAKOTA AND EASTERN NEBRASKA. NARROW BANDS OF SNOW SHOWERS CONTINUE TO WORK SOUTHEASTWARD AFFECTING AREAS EAST OF A LINE FROM ALEXANDRIA TO LITCHFIELD AND ON TRACK TO AFFECT AREAS FROM LITCHFIELD TO RED WING AND POINTS EAST. BANDS OF SNOW ARE MATCHING UP WELL WITH CYCLONIC VORTICITY ADVECTION ON LEADING EDGE OF FAIRLY CHANNELED VORT CENTER. RUC 285K ISENTROPIC SFC SHOWS MOIST ASCENT AND SATURATION LINING UP WELL WITH BANDS AS WELL. PRIMARY TIME FRAME FOR SNOWFALL WILL BE BETWEEN NOW AND 18Z AS COLD ADVECTION TAKES OVER AND ISENTROPIC ASCENT PASSES BY. A DUSTING TO A TENTH OR 2 OF ACCUMULATION IS EXPECTED WITH PERHAPS ISOLATED NARROW BANDS OF A HALF INCH UNDER THE HEAVIER BANDS. TRIMMED POPS BACK TO SLIGHT IN THE AREAS SEEING SNOW THIS MORNING AFTER 18Z WITH HEIGHT RISES QUICKLY TAKING OVER BY LATE AFTERNOON AND SHIFT OF QG FORCING TO THE SOUTHEAST. HOWEVER WITH CYCLONIC FLOW AND COLD ADVECTION WITH ASSOCIATED BRIEF PERIOD OF STEEPENING LAPSE RATES...WILL KEEP FLURRIES IN THROUGH THE AFTERNOON ACROSS THE WESTERN AND SOUTHERN CWA WITH LOW LEVEL MOISTURE STAYING ABUNDANT ABOVE THE SFC. TRIMMED HIGHS A BIT THIS AFTERNOON AND WILL LIKELY SEE TEMPS START TO FALL IN THE NORTH DURING THE AFTERNOON SO HAVE INCORPORATED THIS TREND INTO THE HOURLY TEMP GRIDS. BRIEF PERIOD OF STRONG NORTHWEST WINDS WILL DEVELOP AS SFC LOW DROPS SOUTH OF THE AREA...ESPECIALLY ACROSS THE WESTERN CWA. SFC HIGH PRESSURE WILL BEGIN TO BUILD IN MONDAY MORNING. ANOTHER WEAK SHORTWAVE WILL WILL DROP DOWN IN THE FAST NORTHWEST FLOW BUT THE UPPER RIDGE OFF TO THE WEST WILL HAVE SHIFTED SLIGHTLY EAST SO THIS WAVE SHOULD TRACK FURTHER EAST THAN THE CURRENT ONE. NONETHELESS IT WILL PASS CLOSE ENOUGH TO THE FAR EASTERN CWA TO MAINTAIN LOW CHANCE POPS THERE MONDAY. THE ATMOSPHERE WILL DRY OUT LATER MONDAY AS THE SFC HIGH BUILDS IN. WE HAVE SEEN SOME INCONSISTENCY WITH THE SPEED OF THE HIGH BUT FEEL PRETTY COMFORTABLE WITH IT BEING SQUARELY OVER THE EASTERN HALF OF THE CWA TUESDAY MORNING SUPPORTING VERY COLD LOW TEMPERATURES. INTERESTINGLY...THE ECMWF WHICH WAS SLOWER WITH THE HIGHS MOVEMENT LAST NIGHT AT THIS TIME IS NOW FASTER THAN THE GFS. IN FACT IT REMAINS FASTER WITH THE PATTERN THROUGH THE REST OF THE WEEK. SOUTH WINDS WILL BUILD IN TUESDAY AFTERNOON FROM WEST TO EAST. LOW AND MID LEVEL WARM ADVECTION GETS UNDERWAY TUESDAY AFTERNOON. THE GFS AND ECMWF ARE AT ODDS ON SPEED AND TRACK OF THE NEXT CLIPPER. THE GFS HAS HAD A LITTLE BETTER PERFORMANCE WITH THE SPEED AND TRACK OF THE CLIPPERS THUS FAR SO WILL LEAN TOWARD ITS SOLUTION. STRONGEST MID LEVEL WAA AND CORRESPONDING ISENTROPIC ASCENT CROSSES THE AREA TUESDAY AFTERNOON. BEST MOISTURE WILL BE OFF TO THE NORTH AND EAST SO WILL KEEP POP BELOW MENTIONABLE LEVELS. HOWEVER SOME LIGHT DRIZZLE MAY RESULT WITH FORECAST SOUNDINGS INDICATING A SATURATED LAYER BELOW THE DENDRITIC GROWTH ZONE. ABOVE FREEZING MID LEVELS WILL BE MOVING IN SO WILL HAVE TO WATCH SFC TEMPS FOR FREEZING DRIZZLE POTENTIAL. WARMEST READINGS WILL BE FOUND IN THE SOUTH TUESDAY AND EARLY WEDNESDAY BEFORE COLD ADVECTION GETS GOING WEDNESDAY AFTERNOON. HIGH PRESSURE QUICKLY ARRIVES THURSDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/MDB mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 556 AM CST SUN NOV 16 2008 .UPDATE...FOR 12Z AVIATION DISCUSSION BELOW && .DISCUSSION.../ISSUED 319 AM CST SUN NOV 16 2008/ DEEP LONGWAVE TROUGH NOW ESTABLISHED FROM HUDSON BAY THROUGH THE LOWER GREAT LAKES AND INTO THE SOUTHEAST U.S. UPPER LEVEL HIGH WHICH HAS BEEN PARKED OFF THE CALIFORNIA COAST NOW MAKING SOME EASTWARD PROGRESS TOWARDS THE WEST COAST. THE PATTERN WILL PROGRESS EASTWARD THROUGH THE WEEK WITH UPPER TROUGH CONTINUING TO ROTATE OVER HUDSON BAY WHILE THE SOUTHERN PORTION OF THE TROUGH PIVOTS NORTHEASTWARD OFF THE ATLANTIC COAST THROUGH MIDWEEK. THE UPPER HIGH WILL WORK TOWARDS THE FOUR CORNERS BY MIDWEEK AS WELL. THE UPPER FLOW WILL FLATTEN OVERHEAD BUT REMAIN NORTHWESTERLY AND TRY TO TRANSITION TO WESTERLY THEN SOUTHWESTERLY NEXT WEEKEND. THE FIRST IN A SERIES OF SHORTWAVES APPEARS IN EARLY MORNING WATER VAPOR IMAGERY CROSSING NORTHERN MINNESOTA IN THE FAST NORTHWEST FLOW OVERHEAD. ANOTHER WILL APPROACH MIDWEEK. THIS WILL BRING A BIT OF A ROLLER COASTER RIDE TEMPERATURE WISE THROUGH THE FORECAST PERIOD AS COLD AIR SPILLS IN BEHIND EACH TROUGH AND WARM ADVECTION SPREADS IN AHEAD. ALBERTA CLIPPER IN THE PROCESS OF CROSSING THE CWA THIS MORNING. OCCLUDING SFC LOW IS OVER SOUTHEAST NORTH DAKOTA AT 09Z WITH WARM FRONT EXTENDING FROM NORTH TO SOUTH ACROSS SOUTHEASTERN SOUTH DAKOTA AND EASTERN NEBRASKA. NARROW BANDS OF SNOW SHOWERS CONTINUE TO WORK SOUTHEASTWARD AFFECTING AREAS EAST OF A LINE FROM ALEXANDRIA TO LITCHFIELD AND ON TRACK TO AFFECT AREAS FROM LITCHFIELD TO RED WING AND POINTS EAST. BANDS OF SNOW ARE MATCHING UP WELL WITH CYCLONIC VORTICITY ADVECTION ON LEADING EDGE OF FAIRLY CHANNELED VORT CENTER. RUC 285K ISENTROPIC SFC SHOWS MOIST ASCENT AND SATURATION LINING UP WELL WITH BANDS AS WELL. PRIMARY TIME FRAME FOR SNOWFALL WILL BE BETWEEN NOW AND 18Z AS COLD ADVECTION TAKES OVER AND ISENTROPIC ASCENT PASSES BY. A DUSTING TO A TENTH OR 2 OF ACCUMULATION IS EXPECTED WITH PERHAPS ISOLATED NARROW BANDS OF A HALF INCH UNDER THE HEAVIER BANDS. TRIMMED POPS BACK TO SLIGHT IN THE AREAS SEEING SNOW THIS MORNING AFTER 18Z WITH HEIGHT RISES QUICKLY TAKING OVER BY LATE AFTERNOON AND SHIFT OF QG FORCING TO THE SOUTHEAST. HOWEVER WITH CYCLONIC FLOW AND COLD ADVECTION WITH ASSOCIATED BRIEF PERIOD OF STEEPENING LAPSE RATES...WILL KEEP FLURRIES IN THROUGH THE AFTERNOON ACROSS THE WESTERN AND SOUTHERN CWA WITH LOW LEVEL MOISTURE STAYING ABUNDANT ABOVE THE SFC. TRIMMED HIGHS A BIT THIS AFTERNOON AND WILL LIKELY SEE TEMPS START TO FALL IN THE NORTH DURING THE AFTERNOON SO HAVE INCORPORATED THIS TREND INTO THE HOURLY TEMP GRIDS. BRIEF PERIOD OF STRONG NORTHWEST WINDS WILL DEVELOP AS SFC LOW DROPS SOUTH OF THE AREA...ESPECIALLY ACROSS THE WESTERN CWA. SFC HIGH PRESSURE WILL BEGIN TO BUILD IN MONDAY MORNING. ANOTHER WEAK SHORTWAVE WILL WILL DROP DOWN IN THE FAST NORTHWEST FLOW BUT THE UPPER RIDGE OFF TO THE WEST WILL HAVE SHIFTED SLIGHTLY EAST SO THIS WAVE SHOULD TRACK FURTHER EAST THAN THE CURRENT ONE. NONETHELESS IT WILL PASS CLOSE ENOUGH TO THE FAR EASTERN CWA TO MAINTAIN LOW CHANCE POPS THERE MONDAY. THE ATMOSPHERE WILL DRY OUT LATER MONDAY AS THE SFC HIGH BUILDS IN. WE HAVE SEEN SOME INCONSISTENCY WITH THE SPEED OF THE HIGH BUT FEEL PRETTY COMFORTABLE WITH IT BEING SQUARELY OVER THE EASTERN HALF OF THE CWA TUESDAY MORNING SUPPORTING VERY COLD LOW TEMPERATURES. INTERESTINGLY...THE ECMWF WHICH WAS SLOWER WITH THE HIGHS MOVEMENT LAST NIGHT AT THIS TIME IS NOW FASTER THAN THE GFS. IN FACT IT REMAINS FASTER WITH THE PATTERN THROUGH THE REST OF THE WEEK. SOUTH WINDS WILL BUILD IN TUESDAY AFTERNOON FROM WEST TO EAST. LOW AND MID LEVEL WARM ADVECTION GETS UNDERWAY TUESDAY AFTERNOON. THE GFS AND ECMWF ARE AT ODDS ON SPEED AND TRACK OF THE NEXT CLIPPER. THE GFS HAS HAD A LITTLE BETTER PERFORMANCE WITH THE SPEED AND TRACK OF THE CLIPPERS THUS FAR SO WILL LEAN TOWARD ITS SOLUTION. STRONGEST MID LEVEL WAA AND CORRESPONDING ISENTROPIC ASCENT CROSSES THE AREA TUESDAY AFTERNOON. BEST MOISTURE WILL BE OFF TO THE NORTH AND EAST SO WILL KEEP POP BELOW MENTIONABLE LEVELS. HOWEVER SOME LIGHT DRIZZLE MAY RESULT WITH FORECAST SOUNDINGS INDICATING A SATURATED LAYER BELOW THE DENDRITIC GROWTH ZONE. ABOVE FREEZING MID LEVELS WILL BE MOVING IN SO WILL HAVE TO WATCH SFC TEMPS FOR FREEZING DRIZZLE POTENTIAL. WARMEST READINGS WILL BE FOUND IN THE SOUTH TUESDAY AND EARLY WEDNESDAY BEFORE COLD ADVECTION GETS GOING WEDNESDAY AFTERNOON. HIGH PRESSURE QUICKLY ARRIVES THURSDAY. ..MDB.. && .AVIATION.../12Z TAF ISSUANCE/ EXPECT SCATTERED SNOW SHOWERS TO AFFECT CENTRAL MN AND WEST CENTRAL WI TAF SITES TODAY...ESPECIALLY THIS MORNING...AS SHORTWAVE ENERGY ON THE WESTERN PERIPHERY OF A BROAD TROUGH CENTERED OVER HUDSON BAY CHANNELS ACROSS THE AREA. WHILE ASSOCIATED CIGS HAVE BEEN OF THE VFR VARIETY OVERNIGHT...ANTICIPATED SCT-BKN CLOUDS CIRCA 2K-3K FEET /CURRENTLY NOTED OVER NRN MN/ TO BUILD SOUTH INTO CENTRAL MN AND WEST CENTRAL TODAY. THE MOST WIDESPREAD SNOW SHOWER ACTIVITY SHOULD OCCUR THIS MORNING CONCURRENT WITH THE BEST ISENTROPIC LIFT ON THE 290K SURFACE...BUT SCATTERED FLURRIES WILL BE POSSIBLE IN THE CYCLONIC FLOW REGIME THROUGH THE AFTERNOON. ASSOCIATED VSBY/S SHOULD BE MAINLY VFR...ALTHOUGH A FEW BANDS COULD PRODUCE BRIEF HIGH-END MVFR VSBY/S PRIOR TO 18Z. EXPECT LOW CLOUDS TO LINGER THROUGH TONIGHT...WITH GRADUAL WEST-TO-EAST SCATTERING OUT NOT EXPECTED TO OCCUR UNTIL MONDAY. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ LS/MDB mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 319 AM CST SUN NOV 16 2008 .DISCUSSION... DEEP LONGWAVE TROUGH NOW ESTABLISHED FROM HUDSON BAY THROUGH THE LOWER GREAT LAKES AND INTO THE SOUTHEAST U.S. UPPER LEVEL HIGH WHICH HAS BEEN PARKED OFF THE CALIFORNIA COAST NOW MAKING SOME EASTWARD PROGRESS TOWARDS THE WEST COAST. THE PATTERN WILL PROGRESS EASTWARD THROUGH THE WEEK WITH UPPER TROUGH CONTINUING TO ROTATE OVER HUDSON BAY WHILE THE SOUTHERN PORTION OF THE TROUGH PIVOTS NORTHEASTWARD OFF THE ATLANTIC COAST THROUGH MIDWEEK. THE UPPER HIGH WILL WORK TOWARDS THE FOUR CORNERS BY MIDWEEK AS WELL. THE UPPER FLOW WILL FLATTEN OVERHEAD BUT REMAIN NORTHWESTERLY AND TRY TO TRANSITION TO WESTERLY THEN SOUTHWESTERLY NEXT WEEKEND. THE FIRST IN A SERIES OF SHORTWAVES APPEARS IN EARLY MORNING WATER VAPOR IMAGERY CROSSING NORTHERN MINNESOTA IN THE FAST NORTHWEST FLOW OVERHEAD. ANOTHER WILL APPROACH MIDWEEK. THIS WILL BRING A BIT OF A ROLLER COASTER RIDE TEMPERATURE WISE THROUGH THE FORECAST PERIOD AS COLD AIR SPILLS IN BEHIND EACH TROUGH AND WARM ADVECTION SPREADS IN AHEAD. ALBERTA CLIPPER IN THE PROCESS OF CROSSING THE CWA THIS MORNING. OCCLUDING SFC LOW IS OVER SOUTHEAST NORTH DAKOTA AT 09Z WITH WARM FRONT EXTENDING FROM NORTH TO SOUTH ACROSS SOUTHEASTERN SOUTH DAKOTA AND EASTERN NEBRASKA. NARROW BANDS OF SNOW SHOWERS CONTINUE TO WORK SOUTHEASTWARD AFFECTING AREAS EAST OF A LINE FROM ALEXANDRIA TO LITCHFIELD AND ON TRACK TO AFFECT AREAS FROM LITCHFIELD TO RED WING AND POINTS EAST. BANDS OF SNOW ARE MATCHING UP WELL WITH CYCLONIC VORTICITY ADVECTION ON LEADING EDGE OF FAIRLY CHANNELED VORT CENTER. RUC 285K ISENTROPIC SFC SHOWS MOIST ASCENT AND SATURATION LINING UP WELL WITH BANDS AS WELL. PRIMARY TIME FRAME FOR SNOWFALL WILL BE BETWEEN NOW AND 18Z AS COLD ADVECTION TAKES OVER AND ISENTROPIC ASCENT PASSES BY. A DUSTING TO A TENTH OR 2 OF ACCUMULATION IS EXPECTED WITH PERHAPS ISOLATED NARROW BANDS OF A HALF INCH UNDER THE HEAVIER BANDS. TRIMMED POPS BACK TO SLIGHT IN THE AREAS SEEING SNOW THIS MORNING AFTER 18Z WITH HEIGHT RISES QUICKLY TAKING OVER BY LATE AFTERNOON AND SHIFT OF QG FORCING TO THE SOUTHEAST. HOWEVER WITH CYCLONIC FLOW AND COLD ADVECTION WITH ASSOCIATED BRIEF PERIOD OF STEEPENING LAPSE RATES...WILL KEEP FLURRIES IN THROUGH THE AFTERNOON ACROSS THE WESTERN AND SOUTHERN CWA WITH LOW LEVEL MOISTURE STAYING ABUNDANT ABOVE THE SFC. TRIMMED HIGHS A BIT THIS AFTERNOON AND WILL LIKELY SEE TEMPS START TO FALL IN THE NORTH DURING THE AFTERNOON SO HAVE INCORPORATED THIS TREND INTO THE HOURLY TEMP GRIDS. BRIEF PERIOD OF STRONG NORTHWEST WINDS WILL DEVELOP AS SFC LOW DROPS SOUTH OF THE AREA...ESPECIALLY ACROSS THE WESTERN CWA. SFC HIGH PRESSURE WILL BEGIN TO BUILD IN MONDAY MORNING. ANOTHER WEAK SHORTWAVE WILL WILL DROP DOWN IN THE FAST NORTHWEST FLOW BUT THE UPPER RIDGE OFF TO THE WEST WILL HAVE SHIFTED SLIGHTLY EAST SO THIS WAVE SHOULD TRACK FURTHER EAST THAN THE CURRENT ONE. NONETHELESS IT WILL PASS CLOSE ENOUGH TO THE FAR EASTERN CWA TO MAINTAIN LOW CHANCE POPS THERE MONDAY. THE ATMOSPHERE WILL DRY OUT LATER MONDAY AS THE SFC HIGH BUILDS IN. WE HAVE SEEN SOME INCONSISTENCY WITH THE SPEED OF THE HIGH BUT FEEL PRETTY COMFORTABLE WITH IT BEING SQUARELY OVER THE EASTERN HALF OF THE CWA TUESDAY MORNING SUPPORTING VERY COLD LOW TEMPERATURES. INTERESTINGLY...THE ECMWF WHICH WAS SLOWER WITH THE HIGHS MOVEMENT LAST NIGHT AT THIS TIME IS NOW FASTER THAN THE GFS. IN FACT IT REMAINS FASTER WITH THE PATTERN THROUGH THE REST OF THE WEEK. SOUTH WINDS WILL BUILD IN TUESDAY AFTERNOON FROM WEST TO EAST. LOW AND MID LEVEL WARM ADVECTION GETS UNDERWAY TUESDAY AFTERNOON. THE GFS AND ECMWF ARE AT ODDS ON SPEED AND TRACK OF THE NEXT CLIPPER. THE GFS HAS HAD A LITTLE BETTER PERFORMANCE WITH THE SPEED AND TRACK OF THE CLIPPERS THUS FAR SO WILL LEAN TOWARD ITS SOLUTION. STRONGEST MID LEVEL WAA AND CORRESPONDING ISENTROPIC ASCENT CROSSES THE AREA TUESDAY AFTERNOON. BEST MOISTURE WILL BE OFF TO THE NORTH AND EAST SO WILL KEEP POP BELOW MENTIONABLE LEVELS. HOWEVER SOME LIGHT DRIZZLE MAY RESULT WITH FORECAST SOUNDINGS INDICATING A SATURATED LAYER BELOW THE DENDRITIC GROWTH ZONE. ABOVE FREEZING MID LEVELS WILL BE MOVING IN SO WILL HAVE TO WATCH SFC TEMPS FOR FREEZING DRIZZLE POTENTIAL. WARMEST READINGS WILL BE FOUND IN THE SOUTH TUESDAY AND EARLY WEDNESDAY BEFORE COLD ADVECTION GETS GOING WEDNESDAY AFTERNOON. HIGH PRESSURE QUICKLY ARRIVES THURSDAY. ..MDB.. && .AVIATION.../06Z TAF ISSUANCE/ FORECAST CONCERN IS THE POTENTIAL FOR A BAND OF SNOW TO MOVE ACROSS MAINLY EAST CENTRAL MN AND PARTS OF WEST CENTRAL WI. SCT MID LEVEL CLOUDS OR VFR CEILINGS EARLY IN THE PERIOD WILL DROP TO MVFR CEILINGS KAXN...KMSP...KRNH...KEAU DURING THE 09Z TO 13Z TIME PERIOD. VSBYS DROPPING TO AS LOW AS 1 1/2SM -SN VCNTY KMSP..KRNH FROM 11Z- 14Z. VSBYS CLOSER TO 2-3SM -SN VCNTY KSTC KEAU. SFC LOW PRES WILL BE MOVING SE ACROSS THE SOUTHERN HALF OF MN DURING THE 12Z- 18Z TIME PERIOD. MVFR CIGS WILL THEN SPREAD OVER MUCH OF THE AREA BEHIND THE LOW PRESSURE AREA. A FEW SNOW SHOWERS ARE POSSIBLE AS WELL BUT WITH VSBYS MAINLY P6SM. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ MDB/JPR mn AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 1017 AM CST SUN NOV 16 2008 .DISCUSSION...IT WAS A RATHER CHILLY START TO THE MORNING ACROSS THE AREA AS WINDS HAVE RELAXED FROM YESTERDAY AND SKIES WERE CLEAR ACROSS MUCH OF THE AREA OVERNIGHT. THIS ALLOWED FOR SOME OF THE COOLEST OVERNIGHT LOWS IN JUST OVER TWO WEEKS. RUC ANALYSIS INDICATES THE CENTER OF 1031MB HIGH PRESSURE IS LOCATED ALONG THE SOUTHEAST TEXAS COAST AND BUILDING ACROSS THE AREA. THIS HAS FILTERED IN THE COOLER AND DRIER AIRMASS CURRENTLY OVER THE REGION. SUNNY SKIES WILL PREVAIL ACROSS THE REGION TODAY AND WINDS WILL BE MUCH MORE RELAXED THAN YESTERDAY. DESPITE THE BELOW NORMAL TEMPERATURES...TODAY WILL BE A RATHER PLEASANT MID AUTUMN DAY AND THE CURRENT FORECAST INDICATES THIS. ONLY CHANGES WERE TO HOURLY TEMPERATURES TO ACCOUNT FOR CURRENT OBSERVATIONAL TRENDS. TEMPS RUNNING ON TRACK GENERALLY IN THE MID 40S. ONLY EXCEPTION BEING IN THE NORTHEAST WHERE SLIGHT CLOUD COVER IS INHIBITING TEMPS SLIGHTLY. HOWEVER...THESE CLOUDS ARE CLEARING OUT AND TEMPS SHOULD WARM QUICKLY. OTHERWISE...NO OTHER CHANGES NEEDED. && .AVIATION...VFR CONDITIONS TO PREVAIL THROUGH MONDAY. WINDS WILL BE MUCH LIGHTER THAN YESTERDAY AND CLEAR SKIES WILL BE THE NORM. WITH A DRY AIRMASS IN PLACE OVER THE REGION...VIS RESTRICTIONS DUE TO FOG SHOULD NOT BE AN ISSUE IN THE MORNING. && .PRELIMINARY POINT TEMPS/POPS... JACKSON 54 33 64 38 / 0 0 0 0 MERIDIAN 55 32 64 36 / 0 0 0 0 VICKSBURG 56 34 64 38 / 0 0 0 0 HATTIESBURG 57 32 66 38 / 0 0 0 0 NATCHEZ 55 33 66 40 / 0 0 0 0 GREENVILLE 56 34 63 37 / 0 0 0 0 GREENWOOD 55 34 62 34 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 28 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 118 AM EST MON NOV 17 2008 .SYNOPSIS... A WESTERLY FLOW OF COLD AIR ACROSS THE RELATIVELY WARM WATERS OF LAKE ERIE AND ONTARIO WILL BRING SIGNIFICANT LAKE EFFECT SNOWS TO THE EASTERN LAKE ONTARIO REGION...TUG HILL PLATEAU...UPPER MOHAWK VALLEY AND WESTERN NEW YORK TONIGHT THROUGH MONDAY. ACROSS MOST OF CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA EXPECT SCATTERED SNOW SHOWERS AND FLURRIES AT TIMES THROUGH MONDAY. ANOTHER COLD FRONT WILL DROP SOUTH OUT OF CANADA MONDAY NIGHT AND BRING ANOTHER REINFORCING SHOT OF EVEN COLDER AIR TO THE REGION. AS A RESULT...TEMPERATURES WILL REMAIN MUCH BELOW NORMAL THROUGH THE END OF THIS WEEK WITH ADDITIONAL LAKE EFFECT SNOWS AND SNOW SHOWERS FROM TIME TO TIME. && .NEAR TERM /THROUGH TODAY/... UPDATE AS OF 1030 PM...HEAVY SNOW BAND SITTING OVER NORTHERN ONEIDA ALONG WITH REPORT OF 7 INCHES IN 2 HOURS PROMPTED AN UPGRADE TO A LES WARNING. FOR THE REST OF ONEIDA COUNTY...NRN ONONDAGA AND NRN MADISON COUNTIES...THE CURRENT FORECAST LOOKS GOOD. THE LES BAND WILL BE IN TRANSITION WHEN IT FINALLY REACHES THESE LOCATIONS MON AM. ADDTNLY TEMPS WILL REMAIN MARGINAL 32-35F IN THE LOWER ELEVATION OF THE LAKE ONTARIO PLAIN THUS LIMITING ACC/S. LEFT THE 2 TO 4 INCHES MAINLY NORTH OF THE THRUWAY IN ONONDAGA AND MADISON CO/S WITH 1 TO 3 INCHES TO THE S. THE ERIE BAND ACROSS THE SOUTHERN TIER IS ALSO MORE INTENSE THAN EXPECTED. IT IS A RELATIVELY NARROW BAND RUNNING ALONG THE ROUTE 17/I-86 CORRIDOR ALL THE WAY FROM STEUBEN COUNTY TO DELAWARE COUNTY. SOME AREAS UNDER THE BAND COULD SEE AN INCH OR TWO. FOR STEUBEN CO...THE HIGHER TERRAIN IN THE SW COULD SEE 2 TO 5 INCHES WITH LITTLE ACC/S FOR THE N AND E IN STEUBEN CO. EARLIER SCAN... KBUF...KTYX AND KBGM 88D SHWS SCT-NUM SHRASN IN C NY AND INTO NE PA. FOR NOW THE ACVTY APPEARS AS BROKEN BANDS IN WRN NY/NRN PA AND MORE UNIFORM IN NC NY. THE LAKES WERE ACTING AS AN AGGREGATE ADDING TO THE LOW-LVL MOISTURE AND THUS INCREASING INSTABILITY AND LOW-LVL LIFT TO SUPPORT THE PRECIP. THE MAIN REASON WHY THIS ACVTY WAS ENHANCING THIS AFTRN WAS THE APPRCHING SHRT WAVE FROM THE LOWER LAKES. THIS FEATURE WAS INTERCEPTING THE ENHANCED LL MOISTURE DOWNWIND OF THE LAKES AND SUPPORTG THE SCT- NUM SHRA/SN IN C NY AND ISLD TO SCT SHRASN IN NE PA. AT THIS POINT TEMPERATURES WERE ABV FREEZING IN MOST OF C NY/NE PA EXCEPT AT THE HIGHEST TERRAIN. THE SNOW WAS NOT COMING DOWN THAT HARD YET EITHER IN C NY/NE PA SO LITTLE ACC/S EXPECTED B4 SUNSET. THE ONLY EXCEPTION WILL BE FAR NRN ONEIDA WHERE SNOWS WERE ALREADY FALLING LIGHTLY AS PER SPOTTER REPORTS. AS THIS UPR LVL WAVE MOVES E THIS EVE...THE LL FLO BACKS A LITTLE MORE WRLY AND...COMBINED WITH LIFT...WILL GET SINGLE BAND LES GOING OFF LAKE ONTARIO AND LAKE ERIE. BUCKET DATA SHOWS ONLY MARGINAL TO MODERATE INSTABILITY AT THIS TIME WITH LAKE TEMP TO 850 MB TEMP DIFFS RUNNING ARD 15-19C. THE FLO WAS ALIGNED FAIRLY WELL FOR A BAND FORMATION. MAIN LIMITING FACTOR FOR THE BGM SERVICE AREA IS THE BAND WILL NOT SET UP FOR LONGER THAN 6 HOURS IN ANY GIVEN LOCATION AS IT WILL BE OSCILLATING A BIT N AND S. THIS WILL KEEP AMNTS BELOW WARNING CRITERIA. AS THIS WAVE PASSES TO THE E MONDAY AM...THE FLO VEERS A LITTLE MORE NWRLY AND THE LAKE ONT BAND WILL DROP SOUTHWARD INTO SC NY DURG THE AFTERNOON MONDAY AND DISSIPATE AS IT LOOSES ITS FETCH OFF LAKE ONTARIO. THE LAKE ERIE BAND WILL ALSO SHIFT SOUTHWARD MONDAY AFTERNOON AND MORPH INTO UPSLOPE SNOWS FOR NRN AND WRN PA. THUS HV CHC POPS FOR SHSN MOST OF CWA MON OUTSIDE LES AREAS. SO THE MAIN QUESTION IS WHICH AREAS GET IMPACTED THE MOST FROM THE LES? THE RUC13...NAM12 AND GFS40 ALL AGREE THAT A SINGLE LES BAND FORMS ACRS THE ERN LAKE ONT COUNTIES INCLUDING NRN ONEIDA CO THIS EVE AND OSCILLATES BETWEEN NRN ONEIDA AND LEWIS CO/S SOUTHWARD TO THE CNTRL 1/3 OF ONEIDA COUNTY...CLIPPING THE FAR NRN PART OF ONONDAGA AND MADISON COUNTIES AT TIMES. FOR NOW IT APPEARS GIVEN THE RESIDENCE TIME OF THE BAND...NRN ONEIDA SHUD RECEIVE THE MOST SNOW...ESP NW PART OF COUNTY WHERE 8 INCHES IS POSSIBLE. THE REST OF NRN ONEIDA AND THE CENTRAL THIRD SHUD SEE 3 TO 6 INCHES. FARTHER S...IN THE SRN 1/3 OF ONEIDA COUNTY 1 TO 3 INCHES IS ANTICIPATED. THUS EXPANDED THE LES ADVY FOR SRN ONEIDA ALSO. NEXT CONCERN IS IF ADVY LEVEL SNOWS FALL ACRS NRN ONONDAGA AND NRN MADISON COUNTIES. TEMPS WILL BE CLSE TO OR SLIGHTLY ABV FREEZING AS PER SYR LAMP DATA AND GFS WHEN THE BAND COMES SOUTH THRU THESE AREAS LATER TONIGHT AND MON MORNING. THE MET GUIDC FOR SYR IS ABV FREEZING PRIMARILY. ALSO NOT SURE HOW LONG THE BAND WILL REMAIN IN THESE AREAS AS IT LIKELY WILL BE ON ITS SOUTHWARD EXCURSION MONDAY FOR IT TO REALLY HIT SYR. SO HAVE 2 TO 4 INCHES IN FAR NRN ONONDAGA AND 1 TO 3 INCHES REST OF ONONDAGA AND ALL OF MADISON. WILL REVISIT THIS WITH A 4 PM ISSUANCE. AS FOR THE LAKE ERIE BAND...WILL IT GET TO STEUBEN CO AND PRODUCE ADVY LEVEL SNOWS? MY INCLINATION AT THIS POINT IS THAT IT IS LIKELY GIVEN THE HIGHER TERRAIN IN THE SW PART OF THE COUNTY AND THE STRG WINDS OFF LAKE ERIE TO CARRY THE LAKE MOISTURE EWRD. RIGHT NOW GRIDS HAVE 2 TO 3 INCHES. EARLY PLANS ARE THAT I WILL LIKELY UPGRADE THIS TO AN ADVY WITH A 4 PM ISSUANCE AND HIT THE WRN 1/2 OF THE COUNTY WITH ADVY ACC/S. MORE COORD WILL OCCUR WITH WFO BUF ON THIS AS MORE DATA IS EVALUATED. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... WITH LARGE SCALE UPR LVL TROF SHARPENING UP OVR THE ERN 1/3 OF THE UNITED STATES AND SHIFTG A BIT EAST OVER A BAROCLINIC ZONE OFFSHORE...GFS...NAM AND EURO ALL HAVE CYCLOGENESIS TAKING PLACE WELL E OF THE MID-ATLANTIC FROM MONDAY NGT THRU WED. WITH A STRG BLOCKING UPR LVL RDG OVR THE NORTH ATLANTIC OCEAN THIS CYCLONE IS SLOW TO MOVE OUT TO SEA...THUS A PROLONGED NRLY FLO OF LL COLD AIR SETS UP FOR MON NGT THRU WED AM. 850 MB TEMPS DROP TO -12C TO -15C FROM TUE THRU WED AM. A DEEP AND RATHER MOIST LL NRLY FLO OF AIR WILL LIKELY GET THE FINGER LAKES SNOW BANDS GOING FROM TUE TO WED AM. WUD NOT BE SURPRISED TO SEE ADVY ACC/S IN THE FINGER LAKES REGION IN THIS TIME FRAME. REST OF AREA WILL SEE A PERIOD OF SN SHWRS MON NGT AS RE-INFORCING SHOT OF COLD AIR MOVES SOUTH ALONG A FRNT BNDRY AND ASSCTD UPR LV WAVE. THERE CUD BE SOME LIGHT ACC/S AS WELL BY MON NGT/TUE AM. THEN FOR THE REST OF TUE INTO WED SEE LITTLE PRECIP OUTSIDE THE LES AREAS OF DOWNWIND OF LAKE ONTARIO WITH A NRLY FLO IN THE FINGER LAKES REGION. IT WILL BE MUCH BELOW NORMAL. WILL HIGHLIGHT LES POTENTIAL IN HWO FOR THE FINGER LAKES REGION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MEAN TROF WILL BE FIXED OVER EASTERN CONUS THIS PERIOD. MULTIPLE JETS WILL DIVE INTO THE WESTERN GREAT LAKES, CARVING OUT THE TROF AND REINFORCING POLAR AIR MASS. VIGOROUS JET ENERGY WILL DIVE INTO IL/IN THURSDAY NIGHT, CAUSING WEAK SFC OFF THE ATLANTIC COAST TO INTENSIFY INTO WELL DEFINED CYCLONE. THE CYCLONE SHOULD REMAIN WELL OFF SHORE AND NOT AFFECT OUR FORECAST AREA WITH PRECIPITATION. SFC HIGH WILL BUILD INTO NY/PA EARLY SATURDAY BRINGING DRY WEATHER. ANOTHER JET ENTERING THE WESTERN GREAT LAKES WILL CAUSE SFC CYCLOGENESIS OVER WESTERN ONTARIO PROVINCE. THIS STORM SYSTEM COULD AFFECT FORECAST AREA LATE SUNDAY, PARTICULARLY NORTHERN COUNTIES. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... TWIN BANDS OF LAKE EFFECT SNOW CONTINUE TO STREAM OFF OF ERIE AND ONTARIO THIS MORNING. DIRECTLY UNDER THE SNOW BANDS, VISIBILITIES ARE FALLING TO 1 MILE OR LESS AND CEILINGS ARE LOWERING INTO IFR TERRITORY. WE BELIEVE THE STEADY SNOW WILL REMAIN OUT OF OUR TERMINALS UNTIL A SECONDARY PUSH OF COLD AIR FROM THE NORTH CAUSES THE BANDS TO BREAK OFF THE LAKE AND HEAD SOUTH. THE TIMING ON THIS IS VERY MUCH UNCERTAIN. HOWEVER MESOSCALE MODEL DATA SEEMS TO INDICATE WE WILL SEE A PUSH INTO RME IN THE NEXT FEW HOURS, AND A BROADER SCALE PUSH SOUTHWARD WILL OCCUR LATE MORNING OR EARLY AFTERNOON. IN THE INTERIM, EXPECT VFR CONDITIONS ON AVERAGE BUT HIGHLY VARIABLE CONDITIONS DUE TO BRIEF SNOW SHOWERS. WE THINK THE BEST CHANCE FOR INTERMITTENT SNOW SHOWERS WILL BE IN ELM AND BGM. OUTLOOK... MON NGT THRU TUE NGT...VFR/MVFR UPSTATE NY WITH SCT -SHSN. VFR NE PA. WED...VFR. WED NITE...BECMG MVFR WITH CHC LIGHT SNOW. THU...MVFR/IFR. CHC LIGHT SNOW. FRI...VFR/MVFR. SCT SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR NYZ037. LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NYZ009. && $$ SYNOPSIS...DJN NEAR TERM...BMW SHORT TERM...DJN LONG TERM...DJP AVIATION...DJP ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 156 PM EST SUN NOV 16 2008 .SYNOPSIS... A DEPARTING LOW PRESSURE SYSTEM OVER EASTERN CANADA WILL BRING RAIN AND SNOW SHOWERS TO CENTRAL NEW YORK AND PORTIONS OF NORTHEAST PENNSYLVANIA THIS AFTERNOON. COLDER AIR MOVING IN THIS AFTERNOON WILL CHANGE THE PRECIPITATION OVER TO ALL SNOW ACROSS MOST OF THE AREA. LAKE EFFECT SNOWS WILL BRING SIGNIFICANT SNOW ACCUMULATIONS TO ONEIDA COUNTY TONIGHT AND MONDAY WITH SCATTERED SNOW SHOWERS ELSEWHERE. A QUICK MOVING SURFACE BOUNDARY WILL MOVE THROUGH MONDAY AFTERNOON WITH ADDITIONAL LIGHT SNOW EXPECTED OVER THE AREA. LAKE EFFECT SNOW ALONG WITH UNSEASONABLY COLD AIR WILL PLAGUE THE REGION THROUGH THE MIDDLE OF THE WEEK. && .NEAR TERM /THROUGH MONDAY/... KBUF...KTYX AND KBGM 88D SHWS SCT-NUM SHRASN IN C NY AND INTO NE PA. FOR NOW THE ACVTY APPEARS AS BROKEN BANDS IN WRN NY/NRN PA AND MORE UNIFORM IN NC NY. THE LAKES WERE ACTING AS AN AGGREGATE ADDING TO THE LOW-LVL MOISTURE AND THUS INCREASING INSTABILITY AND LOW-LVL LIFT TO SUPPORT THE PRECIP. THE MAIN REASON WHY THIS ACVTY WAS ENHANCING THIS AFTRN WAS THE APPRCHING SHRT WAVE FROM THE LOWER LAKES. THIS FEATURE WAS INTERCEPTING THE ENHANCED LL MOISTURE DOWNWIND OF THE LAKES AND SUPPORTG THE SCT-NUM SHRA/SN IN C NY AND ISLD TO SCT SHRASN IN NE PA. AT THIS POINT TEMPERATURES WERE ABV FREEZING IN MOST OF C NY/NE PA EXCEPT AT THE HIGHEST TERRAIN. THE SNOW WAS NOT COMING DOWN THAT HARD YET EITHER IN C NY/NE PA SO LITTLE ACC/S EXPECTED B4 SUNSET. THE ONLY EXCEPTION WILL BE FAR NRN ONEIDA WHERE SNOWS WERE ALREADY FALLING LIGHTLY AS PER SPOTTER REPORTS. AS THIS UPR LVL WAVE MOVES E THIS EVE...THE LL FLO BACKS A LITTLE MORE WRLY AND...COMBINED WITH LIFT...WILL GET SINGLE BAND LES GOING OFF LAKE ONTARIO AND LAKE ERIE. BUFKIT DATA SHOWS ONLY MARGINAL TO MODERATE INSTABILITY AT THIS TIME WITH LAKE TEMP TO 850 MB TEMP DIFFS RUNNING ARD 15-19C. THE FLO WAS ALIGNED FAIRLY WELL FOR A BAND FORMATION. MAIN LIMITING FACTOR FOR THE BGM SERVICE AREA IS THE BAND WILL NOT SET UP FOR LONGER THAN 6 HOURS IN ANY GIVEN LOCATION AS IT WILL BE OSCILLATING A BIT N AND S. THIS WILL KEEP AMNTS BELOW WARNING CRITERIA. AS THIS WAVE PASSES TO THE E MONDAY AM...THE FLO VEERS A LITTLE MORE NWRLY AND THE LAKE ONT BAND WILL DROP SOUTHWARD INTO SC NY DURG THE AFTERNOON MONDAY AND DISSIPATE AS IT LOOSES ITS FETCH OFF LAKE ONTARIO. THE LAKE ERIE BAND WILL ALSO SHIFT SOUTHWARD MONDAY AFTERNOON AND MORPH INTO UPSLOPE SNOWS FOR NRN AND WRN PA. THUS HV CHC POPS FOR SHSN MOST OF CWA MON OUTSIDE LES AREAS. SO THE MAIN QUESTION IS WHICH AREAS GET IMPACTED THE MOST FROM THE LES? THE RUC13...NAM12 AND GFS40 ALL AGREE THAT A SINGLE LES BAND FORMS ACRS THE ERN LAKE ONT COUNTIES INCLUDING NRN ONEIDA CO THIS EVE AND OSCILLATES BETWEEN NRN ONEIDA AND LEWIS CO/S SOUTHWARD TO THE CNTRL 1/3 OF ONEIDA COUNTY...CLIPPING THE FAR NRN PART OF ONONADAGA AND MADISON COUNTIES AT TIMES. FOR NOW IT APPEARS GIVEN THE RESIDENCE TIME OF THE BAND...NRN ONEIDA SHUD RECEIVE THE MOST SNOW...ESP NW PART OF COUNTY WHERE 8 INCHES IS POSSIBLE. THE REST OF NRN ONEIDA AND THE CENTRAL THIRD SHUD SEE 3 TO 6 INCHES. FARTHER S...IN THE SRN 1/3 OF ONEIDA COUNTY 1 TO 3 INCHES IS ANTICIPATED. THUS EXPANDED THE LES ADVY FOR SRN ONEIDA ALSO. NEXT CONCERN IS IF ADVY LEVEL SNOWS FALL ACRS NRN ONONDAGA AND NRN MADISON COUNTIES. TEMPS WILL BE CLSE TO OR SLIGHTLY ABV FREEZING AS PER SYR LAMP DATA AND GFS WHEN THE BAND COMES SOUTH THRU THESE AREAS LATER TONIGHT AND MON MORNING. THE MET GUIDC FOR SYR IS ABV FREEZING PRIMARILY. ALSO NOT SURE HOW LONG THE BAND WILL REMAIN IN THESE AREAS AS IT LIKELY WILL BE ON ITS SOUTHWARD EXCURSION MONDAY FOR IT TO REALLY HIT SYR. SO HAVE 2 TO 4 INCHES IN FAR NRN ONONDAGA AND 1 TO 3 INCHES REST OF ONONDAGA AND ALL OF MADISON. WILL REVISIT THIS WITH A 4 PM ISSUANCE. AS FOR THE LAKE ERIE BAND...WILL IT GET TO STUEBEN CO AND PRODUCE ADVY LEVEL SNOWS? MY INCLINATION AT THIS POINT IS THAT IT IS LIKELY GIVEN THE HIGHER TERRAIN IN THE SW PART OF THE COUNTY AND THE STRG WINDS OFF LAKE ERIE TO CARRY THE LAKE MOISTURE EWRD. RIGHT NOW GRIDS HAVE 2 TO 3 INCHES. EARLY PLANS ARE THAT I WILL LIKELY UPGRADE THIS TO AN ADVY WITH A 4 PM ISSUANCE AND HIT THE WRN 1/2 OF THE COUNTY WITH ADVY ACC/S. MORE COORD WILL OCCUR WITH WFO BUF ON THIS AS MORE DATA IS EVALUATED. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... LAKE EFFECT BAND WILL TAKE AWHILE TO GET ESTABLISHED TONIGHT. ALL INDICATIONS ARE THAT FLOW GOES 270-280 AND BAND SETS UP OVR NRN ONEIDA CNTY IN EARNEST AFTER MIDNIGHT TONIGHT. FLY IN THE OINTMENT IS THAT BUFKIT PROFILES INDICATE THIS BAND WILL MEANDER OVRNGT AND NOT BECOME COMPLETELY ENTRENCHED OVR THE AREA FOR A LARGE AMNT OF TIME. OMEGA PROFILES INDICATE STRONG LIFT AND DENDRITE LAYER MOST FAVORABLE FROM 06Z-12Z MON WITH GREATEST ACC/S EXPECT DRG THIS TIME. QPF INDICATES SNOW AMNTS ON THE ORDER OF 3-6 INCHES OVRNGT TONIGHT ACRS THIS AREA. EXPECT AN ADDITIONAL 1-3 INCHES ON EITHER SIDE OF THIS WITH AN OVERALL STORM TOTAL FROM SUN AFTN THRU MON AFTN OF 5-8 INCHES ACRS NRN ONEIDA/TUG HILL. THUS WILL ISSUE AN ADVISORY FOR THIS EVNG THRU MON AFTN. BNDRY WILL MV ACRS FA MON AFTN WITH AREA OF SNOW DROPPING SOUTH WITH IT. GOOD CONVERGENCE AND FAIRLY DECENT LIFT WILL ACCOMPANY TROF AND SHUD BRING QUICK BURST OF SNOW TO MOST OF THE FA WITH INCH OR TWO AS IT MVS THRU...MAINLY FM TWIN TIERS NORTHWARD. HV UNDERCUT MOS TEMPS FOR MON WITH H8 TEMPS PROGGED TO DROP TO NR -8C. WILL KEEP ALL LOCATIONS IN THE U30S. NRLY FLOW SHIFTS LAKE EFFECT SNOW INTO MORE MULTI-BAND EVENT AFTER MONDAY WITH FLOW FROM 340-350 DEGREES. EXPECT LAKE EFFECT TO CONTINUE OVR THESE AREA THRU END OF SHORT TERM. TEMPS CONTINUE THEIR SLOW FALL THRU MIDDLE OF THE WEEK...BOTTOMING OUT NR -15C BY WED MRNG WITH LOWS IN THE TEENS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A COLD PERIOD REMAINS ON THE HORIZON FOR THE MEDIUM RANGE...WITH A BROAD TROF IN THE EAST THROUGH FRIDAY. HPC DISCUSSIONS SEE LONG WAVE PLACEMENT ISSUES WITH THE GFS RUNS DAYS 5-7...THEREFORE WE HAVE LEANED EXCLUSIVELY WITH THEIR GUIDANCE WHICH REVOLVES AROUND THE ECMWF AND IT/S ENSEMBLES. ALONG WITH THE SUB-NORMAL TEMPERATURES...SOME LIGHT SNOW IS POSSIBLE WEDNESDAY NIGHT AND THURSDAY ASSOCIATED WITH A SMALL CLIPPER LOW MOVING SOUTHEAST OUT OF THE UPR GTLKS. THIS WILL BE FOLLOWED BY WEAK MULTI-BAND LAKE SNOW SHOWERS INTO EARLY SATURDAY. IT APPEARS AS THOUGH THE FLOW MAY TAKE ON A MORE DEFINITIVE NORTHERLY COMPONENT WHICH WOULD MEAN LAKE SNOW SHOWERS HOVERING ALONG AND WEST OF I-81...AS OPPOSED TO THE USUAL DOWNWIND SPOTS. HIGH PRESSURE THEN BUILDS INTO THE AREA FOR SATURDAY AND SUNDAY...WITH A SLIGHT UPWARD MODIFICATION IN TEMPERATURES. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... FLIGHT OPS WILL REVOLVE AROUND DODGING LAKE EFFECT SNOW BANDS THROUGH THE NEXT 24 HRS...WITH VFR CIGS THIS AFTERNOON BECOMING MORE WDSPRD MVFR TONIGHT. WE WILL SEE TWO MAIN LAKE BANDS OFF ERIE AND ONTARIO PASSING THROUGH THE UPSTATE NY TERMINALS. THE STRONGEST BAND WILL BE OFF ONTARIO AND AFFECT KRME FOR A GOOD PART OF THE NIGHT WITH CIGS/VSBYS FALLING TO IFR/LIFR. AIRPORT OPS SHOULD PLAN ON THE NEED FOR SNOW REMOVAL AND TREATMENT OPERATIONS. THE CORE OF THE LAKE SNOW BAND MAY LIFT NORTH OF KRME JUST BEFORE 12Z TO PROVIDE A BREAK TO MVFR AND LIGHTER ACCUMS. KSYR LOOKS TO BE ON THE SRN FRINGE OF HEAVY SNOW BAND WITH MAINLY MVFR CONDITIONS...AND SOME LIGHT PLOWABLE SNOW. KELM-KITH-KBGM WILL RECEIVE SNOW SHOWERS AND MVFR RESTRICTED CIGS/VSBYS FROM INTRUSION OF LK ERIE BAND...ALTHOUGH THESE ARE EXPECTED TO IMPROVE AFT 12Z. ONLY VFR STATION LOOKS TO BE KAVP. A WEAK FRONT DROPS SOUTH THROUGH THE AREA ON MONDAY WITH A CONTINUATION OF SNOW SHOWERS AND VARIABLE VFR/MVFR CONDITIONS. GUSTY NW WINDS TO 25-30 KTS THIS AFTERNOON WILL SUBSIDE TO 10-15 KTS THIS EVENING THROUGH MONDAY. OUTLOOK... MON NGT THRU TUE NGT...VFR/MVFR UPSTATE NY WITH SCT -SHSN. VFR NE PA. WED...VFR. WED NITE...BECMG MVFR WITH CHC LIGHT SNOW. THU...MVFR/IFR. CHC LIGHT SNOW. FRI...VFR/MVFR. SCT SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 4 PM EST MONDAY FOR NYZ009-037. && $$ SYNOPSIS...DJN NEAR TERM...DJN SHORT TERM...PVN LONG TERM...JAB AVIATION...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 644 AM EST SUN NOV 16 2008 .SYNOPSIS... A DEPARTING LOW PRESSURE SYSTEM WILL BRING RAIN AND SNOW SHOWERS TO CENTRAL NEW YORK AND PORTIONS OF NORTHEAST PENNSYLVANIA TODAY. COLDER AIR MOVING IN THIS AFTERNOON WILL CHANGE THE PRECIPITATION OVER TO ALL SNOW ACROSS MOST OF THE AREA. LAKE EFFECT SNOWS WILL BRING MODERATE ACCUMULATIONS TO THE TUG HILL PLATEAU TONIGHT AND MONDAY WITH SCATTERED SNOW SHOWERS ELSEWHERE. A QUICK MOVING SURFACE BOUNDARY WILL MOVE THROUGH MONDAY AFTERNOON WITH ADDITIONAL LIGHT SNOW EXPECTED OVER THE AREA. LAKE EFFECT SNOW ALONG WITH UNSEASONABLY COLD AIR WILL PLAGUE THE REGION THROUGH THE MIDDLE OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AREA OF PCPN OVR ERN ZONES IS TRANSLATING EAST AND SHUD EXIT FA IN THE NEXT 2-3 HRS. THIS RAIN IN ASSOC WITH RRQ OF +150KT SPEED MAX AT UPPER LVLS. MODELS HVG HARD TIME PICKING UP ON QPF ASSOC WITH THIS FEATURE. LATEST RUC GUIDANCE AND RADAR TRENDS INDICATE RAIN WILL MV OUT OF AREA ARND 09Z. THIS WUD LV MOST OF FA IN A RELATIVE LULL FOR A TIME EARLY THIS MRNG. WRAP-AROUND IS KNOCKING ON THE DOOR OVR WRN SXNS OF FA THIS MRNG AS SECONDARY FRONT MVS THRU WRN NY WITH SW WINDS OVR FINGER LKS AND W-NW WINDS FROM BUF-ERI. AS THIS BNDRY MVS THRU...SHUD SEE PCPN TRANSLATE EAST INTO CNTRL AREAS BY MID-MRNG. H5 TROF WILL SLOWLY LIFT THRU FA BY 18Z THIS AFTN. THRU THIS TIME...EXPECT CHC POPS OVR TWIN TIERS/WRN CATSKILLS TO CATEGORICAL FINGER LKS/TUG HILL. GIVEN TEMPS STARTING OFF RELATIVELY WARM IN THE 40S...PCPN WILL LIKELY BE A MIX OF RA/SN UNTIL TEMPS BEGIN TO COOL AFTER 18Z. HV TRENDED TEMPS TO BE FAIRLY STEADY THRU THIS TIME BFR DROPPING SLIGHTLY DRG THE AFTN. TEMPS AT SFC AND ALOFT SHUD COOL ENUF BY 18Z TO WARRANT ALL SNOW MENTION AT THIS POINT...ALTHO DEEP VLYS MAY HOLD ON TO WARM TEMPS LONG ENUF FOR A MIX UNTIL LATE AFTN. ONCE TROF LIFTS OUT PCPN WILL BE CONFINED TO MORE FAVORED LK EFFECT REGIONS ACRS UPSTATE NY. FLOW WILL ALIGN OUT OF THE WEST WITH MEAN WIND OF 270-280 DEGREES. THIS FLOW WUD TARGET THE TUG HILL AREA OF NRN ONEIDA CNTY THIS AFTN. CUD ALSO SEE PORTIONS OF LK ERIE BAND REACHING INTO WRN SXNS OF STEUBEN CNTY THIS AFTN. WITH TEMPS STILL IN THE MID 30S...EXPECT ONLY AN INCH OR TWO OF ACC/S ACRS THESE AREAS TODAY WITH RMNDR OF CNTRL NY UNDER A HALF INCH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... LAKE EFFECT BAND WILL TAKE AWHILE TO GET ESTABLISHED TONIGHT. ALL INDICATIONS ARE THAT FLOW GOES 270-280 AND BAND SETS UP OVR NRN ONEIDA CNTY IN EARNEST AFTER MIDNIGHT TONIGHT. FLY IN THE OINTMENT IS THAT BUFKIT PROFILES INDICATE THIS BAND WILL MEANDER OVRNGT AND NOT BECOME COMPLETELY ENTRENCHED OVR THE AREA FOR A LARGE AMNT OF TIME. OMEGA PROFILES INDICATE STRONG LIFT AND DENDRITE LAYER MOST FAVORABLE FROM 06Z-12Z MON WITH GREATEST ACC/S EXPECT DRG THIS TIME. QPF INDICATES SNOW AMNTS ON THE ORDER OF 3-6 INCHES OVRNGT TONIGHT ACRS THIS AREA. EXPECT AN ADDITIONAL 1-3 INCHES ON EITHER SIDE OF THIS WITH AN OVERALL STORM TOTAL FROM SUN AFTN THRU MON AFTN OF 5-8 INCHES ACRS NRN ONEIDA/TUG HILL. THUS WILL ISSUE AN ADVISORY FOR THIS EVNG THRU MON AFTN. BNDRY WILL MV ACRS FA MON AFTN WITH AREA OF SNOW DROPPING SOUTH WITH IT. GOOD CONVERGENCE AND FAIRLY DECENT LIFT WILL ACCOMPANY TROF AND SHUD BRING QUICK BURST OF SNOW TO MOST OF THE FA WITH INCH OR TWO AS IT MVS THRU...MAINLY FM TWIN TIERS NORTHWARD. HV UNDERCUT MOS TEMPS FOR MON WITH H8 TEMPS PROGGED TO DROP TO NR -8C. WILL KEEP ALL LOCATIONS IN THE U30S. NRLY FLOW SHIFTS LAKE EFFECT SNOW INTO MORE MULTI-BAND EVENT AFTER MONDAY WITH FLOW FROM 340-350 DEGREES. EXPECT LAKE EFFECT TO CONTINUE OVR THESE AREA THRU END OF SHORT TERM. TEMPS CONTINUE THEIR SLOW FALL THRU MIDDLE OF THE WEEK...BOTTOMING OUT NR -15C BY WED MRNG WITH LOWS IN THE TEENS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MODELS ARE IN GOOD AGREEMENT ON A PERIOD OF UNSEASONABLY COLD WEATHER WEDNESDAY THROUGH SATURDAY. MODEL DISAGREEMENTS REVOLVE AROUND TIMING AND INTENSITY OF A CLIPPER SYSTEM DIVING SOUTHEAST ACROSS THE AREA IN NORTHWESTERLY FLOW ALOFT ON THURSDAY. THE GFS IS STRONGER WITH THIS SYSTEM THAN THE ECMWF ON TODAY`S RUNS. WHILE MUCH OF THIS EXTENDED PERIOD WILL FEATURE A CHANCE OF SNOW SHOWERS OVER UPSTATE NY... THERE WILL PROBABLY BE A LULL IN THE ACTIVITY ON WEDNESDAY AHEAD OF THIS CLIPPER SYSTEM. POPS INCREASE LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THE CLIPPER SYSTEM. A RE- REINFORCING SHOT OF COLD AIR WILL FOLLOW IN THE WAKE OF THE CLIPPER ON FRIDAY WITH MORE LAKE EFFECT SNOW. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... FLIGHT OPERATIONS WILL BE HAMPERED BY STRONG W-NW WINDS TODAY THAT ARE EXPECTED TO GUST AROUND 30 KTS FOR MUCH OF THE DAYLIGHT HOURS. CIGS WILL BE MAINLY MVFR WITHIN AREAS OF LIGHT SNOW FLURRY ACTIVITY AND DRIZZLE ACROSS UPSTATE NY TERMINALS. MAINLY VFR EXPECTED AT KAVP. A STRONG LAKE EFFECT SNOW BAND WILL BECOME ESTABLISHED IN THE VICINITY OF KRME...ALTHOUGH THE STRONGEST CORE IS EXPECTED TO BE MAINLY NORTH OF THE AIRPORT. BELIEVE THERE WILL BE IFR CONDITIONS IN SNOW DEVELOPING AFT 04Z AT KRME...BUT UNCERTAIN AS TO WHETHER OR NOT THE INTENSE WHITEOUT CORE OF SNOW BAND WILL GET INTO THE TERMINAL. AIRPORT OPS CAN EXPECT PLOWABLE SNOWFALL TONIGHT AND MONDAY. KSYR MAY ALSO SEE OCNL SNOW SHOWERS THROUGH THE NIGHT...BUT MAINLY MVFR AND LIGHTER ACCUMS. ELSEWHERE...CIGS/VSBYS SHOULD BECOME VFR. OUTLOOK... MON...VFR. AREAS MVFR WITH SCT LAKE SNOW SHOWERS KRME-KSYR. MON NGT/TUES/TUES NGT...MVFR UPSTATE NY IN -SHSN...GNRLY VFR NE PA. WED...VFR. THU...MVFR/IFR. LIGHT SNOW DEVELOPING. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 4 PM EST MONDAY FOR NYZ009. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...JAB/MSE AVIATION...JAB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 640 AM EST MON NOV 17 2008 .SYNOPSIS... HIGH PRESSURE CENTERED OVER THE WESTERN GULF COAST WILL EXTEND INTO THE CAROLINAS THIS MORNING. A DRY COLD FRONT WILL CROSS OUR REGION THIS AFTERNOON AND BRING WELL BELOW NORMAL TEMPERATURES TO CENTRAL NC THROUGH MID WEEK. A BRIEF MODERATION IS EXPECTED AHEAD OF A DRY COLD FRONT THURSDAY BEFORE A RETURN TO WELL BELOW NORMAL TEMPERATURES FRIDAY THROUGH SATURDAY. && .NEAR TERM /TODAY THROUGH TONIGHT/... AS OF 245 AM MONDAY... THE FORECAST CHALLENGES THIS WEEK ARE STARTING EARLY... WITH AND BEHIND A CLIPPER COLD FRONT THAT WILL DROP THROUGH THE STATE FROM MID AFTERNOON THROUGH EARLY THIS EVENING. A NARROW BUT THICK BAND OF OROGRAPHICALLY ENHANCED MID AND HIGH CLOUDS DEVELOPED EAST OF THE VA AND NRN NC MOUNTAINS A FEW HOURS AGO... WITHIN A VERTICAL WIND AND TEMPERATURE PROFILE IDEAL FOR SUCH CONDITIONS... INCLUDING A SIGNIFICANT WNW WIND COMPONENT... INCREASING WIND SPEEDS WITH HEIGHT... A DEEP STABLE LAYER ALOFT... AND MOISTURE ABOVE MOUNTAINTOP LEVEL. WITH SATELLITE IMAGERY INDICATING ADDITIONAL MOISTURE ALOFT UPSTREAM OVER KY AND TN... AND WITH OTHER CONDITIONS IN THE VERTICAL REMAINING FAIRLY STEADY STATE THROUGH MORNING... ADDITIONAL MID/HIGH CLOUDINESS OVER THE NW CWA IS LIKELY THROUGH MID MORNING. THEN THE FOCUS SHIFTS TO THE INCOMING UPPER JET CORE NOW OVER THE DAKOTAS AND NOSING INTO NE/KS/IA/MO AND THE SURFACE FRONT. CURRENTLY A POCKET OF UPPER DIVERGENCE WITHIN THE EXIT REGION OF THIS JET APPEARS TO BE A PRIMARY SUPPORTER OF PRECIP BLOSSOMING OVER MO AND NE KS. WHILE THE CLOUD BASES HERE ARE AT OR ABOVE 6000 FT... SOME OF THIS IS INDEED REACHING THE GROUND AS LIGHT RAIN WAS REPORTED AT FNB AND MCI. INTERESTINGLY... AMONG THE GFS/ WRF-NMM/ WRF-ARW/ CANADIAN/ ECMWF... NO MODEL INITIALIZED THIS PRECIP... LEADING US TO CONCLUDE THAT THE FORCING WITH THIS JET IS LIKELY STRONGER THAN THE MODELS INDICATE. WHILE FORECAST SOUNDINGS CONTINUE TO SHOW INSUFFICIENT MOISTURE IN THE LOWEST FEW THOUSAND FEET FOR ANY PRECIP ALOFT TO REACH THE GROUND... CONSIDERING THE POSSIBILITY OF STRONGER-THAN-EXPECTED FORCING FOR ASCENT... THE POTENTIAL FOR A QUICK SPRINKLE OR TWO LATER TODAY DOES EXIST. AT THE VERY LEAST WE ARE VERY LIKELY TO SEE GREATER SKY COVER TODAY... ESPECIALLY ACROSS THE NORTH AND WEST SECTIONS WHERE THE NAM AND RUC TRACK THE JET`S UPPER DIVERGENCE MAXIMUM. WE SHOULD ALSO SEE WINDS KICK UP TODAY BOTH AHEAD OF AND BEHIND THE FRONT... WITH 850 MB WINDS EXPECTED TO INCREASE TO 25+ KTS WITH A DEEPENING MIXED LAYER... PLUS UPSTREAM STATIONS HAVE REPORTED SPORADIC GUSTS OF 15-22 KTS. CONTINUED BELOW-NORMAL THICKNESSES FACTORING IN THE LIKELY DRY ADIABATIC LOW LEVEL THERMAL PROFILE YIELD HIGHS OF 53-59... SLIGHTLY DOWN FROM THE PREVIOUS FORECAST. BLUSTERY WINDS SHOULD PERSIST INTO THE EVENING BEFORE THEY BEGIN TO DIMINISH... AND CLOUDS SHOULD BRIEFLY DECREASE TONIGHT IN THE WAKE OF THE UPPER JET FORCING AND SURFACE FRONT. HOWEVER CLOUDS ARE EXPECTED TO INCREASE ANEW VERY LATE TONIGHT AS AN INTENSE MID LEVEL VORTICITY MAXIMUM DROPS FROM WI TOWARD NC. LOWS TONIGHT ARE GREATLY DEPENDENT ON HOW MUCH SKY COVER THERE IS... HOWEVER BASED ON CURRENT TEMPS AND UPSTREAM TRENDS... HAVE KEPT LOWS BELOW NORMAL... 29-34. -GIH && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... AS OF 230 AM MONDAY... TUESDAY AND TUESDAY NIGHT: VERY INTERESTING FORECAST FOR THIS PERIOD! BOTH THE GFS/NAM SHOW A VERY STRONG UPPER LEVEL WAVE DIVING SOUTHEAST THROUGH THE OH VALLEY TOWARD THE MID-ATLANTIC EARLY TUESDAY MORNING...CLOSING OFF INTO AN UPPER LOW OVER THE DELMARVA PENINSULA BY 18Z TUE AFTERNOON. BASED ON THE 00Z RUNS...THE NAM IS THE STRONGER OF THE TWO...SHOWING A 30-35/S VORT MAX CROSSING CENTRAL NC BETWEEN ROUGHLY SUNRISE AND NOON. BOTH THE GFS/NAM SHOW H5 HEIGHTS DROPPING BELOW 5400 METERS OVER MOST OF CENTRAL NC BY 12Z TUE...WITH 1000-850 MB THICKNESSES RANGING FROM 1275 METERS (NW) TO 1285 METERS (SE) THROUGHOUT THE ENTIRE DAY...AND 850 MB TEMPS IN THE -8 TO -10C RANGE. THE MSLP GRADIENT ACROSS THE AREA WILL BE RATHER TIGHT...WITH THE MID ATLANTIC AND CAROLINAS SANDWICHED BETWEEN A 1035-1040 MB HIGH IN THE MIDWEST AND A DEEPENING SFC LOW OFFSHORE THE MID-ATLANTIC. FCST SOUNDINGS SHOW 25-30 KT FLOW THROUGHOUT A DEEP MIXED LAYER ACROSS THE ENTIRE AREA. THE RESULT OF ALL OF THIS WILL BE A VERY COLD AND BLUSTERY DAY ACROSS CENTRAL NC. ALTHOUGH MOS GUIDANCE IS SHOWING HIGH TEMPS IN THE MID/UPPER 40S ACROSS THE AREA...BOTH THE THICKNESSES AND 850 MB TEMPS POINT TO HIGHS WELL BELOW MOS GUIDANCE...RANGING FROM THE UPPER 30S TO LOWER 40S. ALTHOUGH THE LOW LEVEL FLOW WILL BE ABOUT AS GOOD AS IT GETS FOR DOWNSLOPE WARMING/DRYING...EXPECT THAT SUCH STRONG COLD ADVECTION WILL OFFSET ANY COMPRESSIONAL WARMING THAT RESULTS...AND WILL FCST HIGHS RANGING FROM 39F IN THE TRIAD TO 43F IN THE SE COASTAL PLAIN. ADDITIONALLY...WITH 25-30 KT FLOW IN THE MIXED LAYER...EXPECT SUSTAINED NW WINDS IN THE 15-20 MPH RANGE...WITH GUSTS AS HIGH AS 30 MPH. EXPECT THAT WIND CHILL VALUES IN THE MORNING HOURS WILL BE IN THE LOWER/MID 20S. NOW...HERE COMES THE REALLY INTERESTING PART OF THE FORECAST. SOUNDINGS ARE SHOWING SATURATION W/RESPECT TO ICE OR NEAR SATURATION IN THE CRITICAL -10 TO -20C REGION ACROSS PORTIONS OF THE AREA TUE MORNING THROUGH EARLY AFTERNOON...WITH EXTREMELY STEEP (DRY ADIABATIC) LAPSE RATES ALL THE WAY UP TO 700 MB! AT THE SAME TIME...A POTENT VORT MAX ASSOC/W A STRONG SHORTWAVE WILL BE APPROACHING AND SWEEPING ACROSS THE AREA FROM THE NORTHWEST. NOW...THE GFS IS A BIT WEAKER AND FURTHER NORTH WITH THIS WAVE...HOWEVER...THE NAM IS STRONGER AND TAKES THE STRONGEST ENERGY DIRECTLY OVER CENTRAL NC. IN ADDITION TO CURVATURE VORTICITY IN ASSOC/W THE SHORTWAVE...CYCLONIC SHEAR VORTICITY SHOULD ALSO BE PRESENT ACROSS THE AREA GIVEN A VERY STRONG (125 KT) JET PROGGED JUST TO OUR SOUTH TUE MORNING AND EARLY TUE AFTERNOON. THESE FACTORS ALL POINT TO A POTENTIAL FOR ISOLD CONVECTIVE PRECIPITATION ACROSS PORTIONS OF THE AREA...WITH THE BEST CHANCE NORTH OF HWY 64 IN THE TRIANGLE AND NORTHEAST COASTAL PLAIN. GIVEN THE UNSEASONABLY COLD AIRMASS IN PLACE...WITH THICKNESSES OF 1275-1285 METERS PROGGED ACROSS THE ENTIRE AREA AND LOW LEVEL WETBULB TEMPS NEAR OR BELOW FREEZING...IF ANY ISOLD CONVECTIVE PRECIP DID DEVELOP...IT WOULD FALL AS SNOW. NOW...GIVEN SUCH STRONG DOWNSLOPE FLOW AND DRYING IN THE LOWEST LEVELS...WE WILL MOST LIKELY SEE ONLY VIRGA OR FLURRIES WITH ANY CONVECTIVE PRECIP ECHOES. HOWEVER...IF THE UPPER LEVEL LIFT IS STRONG ENOUGH...IT IS NOT TOO MUCH OF A STRETCH THAT WE COULD SEE A FEW BRIEF CONVECTIVE SNOW SHOWERS. AT THIS TIME...WILL FORECAST PARTLY CLOUDY SKIES WITH A SLIGHT CHANCE OF FLURRIES ALONG/NORTH OF HWY 64 ON TUE MORNING AND EARLY AFTERNOON. ON TUESDAY NIGHT WE SHOULD SEE A CLEARING TREND AS THE UPPER TROUGH PASSES OFFSHORE AND THE MID-ATLANTIC/CAROLINAS EXPERIENCE STRONG SUBSIDENCE ALOFT. COLD ADVECTION WILL LIKELY STILL BE UNDERWAY AT THE SFC AS HIGH PRESSURE CONTINUES TO BUILD IN FROM THE WEST...AND EXPECT A CHILLY 10 KT NORTHWESTERLY WIND OVERNIGHT. THIS AMOUNT OF WIND WILL KEEP TEMPS FROM PLUMMETING AS MUCH AS THE THICKNESSES WOULD SUGGEST (1265-1275 METER THICKNESSES SUGGEST LOWS NEAR 20F)...AND WILL FCST LOWS RANGING FROM 23-27F. WITH A 10 MPH NW WIND...WIND CHILL VALUES COULD POSSIBLY DROP INTO THE MID/UPPER TEENS TUE NIGHT. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT A -NAO PATTERN THROUGH THE END OF THE UPCOMING WORK WEEK. THIS -NAO PATTERN WILL BE CHARACTERIZED BY A POSITIVE HEIGHT ANOMALY STRETCHING FROM THE NORTHERN ATLANTIC NORTHWESTWARD INTO THE DAVIS STRAIT/SOUTHERN GREENLAND...WITH AN UPSTREAM NEGATIVE HEIGHT ANOMALY OVER SOUTHEASTERN CANADA...AND RESULTANT L/W TROUGHING ALONG OR JUST OFF THE US EAST COAST. HEIGHTS ALOFT THEN BEGIN TO RISE THIS WEEKEND COURTESY OF BROAD RIDGING ALOFT APPROACHING FROM THE WEST...WHICH SHOULD SHOULD RESULT IN A GRADUAL MODERATING TREND SATURDAY INTO SUNDAY. WEDNESDAY: WITH TEMPS STARTING OUT IN THE LOWER/MID 20S WED MORNING...12Z THICKNESSES PROGGED TO BE AROUND 1265 METERS...AND 00Z THICKNESSES PROGGED TO RANGE FROM 1300 METERS IN THE WESTERN PIEDMONT TO 1290 METERS IN THE EAST/NORTHEAST COASTAL PLAIN...WILL FCST ANOTHER CHILLY DAY ACROSS THE AREA...WITH HIGHS RANGING FROM 42F (NE COASTAL PLAIN) TO 46F IN THE WEST/SW PIEDMONT. EXPECT SUNNY OR MOSTLY SUNNY SKIES WED GIVEN CONTINUED SUBSIDENCE/WARMING IN THE MID/UPPER LEVELS AND DOWNSLOPE FLOW IN THE LOWER LEVELS. WEDNESDAY NIGHT AND THURSDAY: A S/W TROUGH ALOFT AND ASSOCIATED WEAK SURFACE LOW ARE EXPECTED TO DIVE SOUTHEASTWARD ACROSS THE GREAT LAKES TO THE SOUTHERN NEW ENGLAND COAST WEDNESDAY NIGHT AND THURSDAY. AN ATTENDANT DRY COLD FRONT WILL CROSS CENTRAL NC THURSDAY AFTERNOON. PRIOR TO THE FROPA... LOWS THURSDAY MORNING WITH LIGHT SOUTHWESTERLY STIRRING ARE EXPECTED TO DIP TO AROUND 30 DEGREES. A BRIEF WAA REGIME AHEAD OF THE S/W TROUGH WILL HELP BOOST TEMPERATURES TO THEIR WARMEST READINGS OF THE WEEK THURSDAY AFTERNOON...THOUGH STILL BELOW AVERAGE IN THE LOWER TO MIDDLE 50S. FRIDAY AND FRIDAY NIGHT: NNW`RLY LOW LEVEL FLOW AROUND AN INCOMING 1030+ MB SURFACE HIGH AND FRESH CP AIRMASS BEHIND THE FRONT SHOULD SUPPRESS TEMPERATURES INTO THE 40S FRIDAY...DESPITE MOSTLY SUNNY SKIES. WITH THE SURFACE HIGH NEARBY OR DIRECTLY OVERHEAD BY FRIDAY NIGHT...LOWS SHOULD DIP INTO THE 25 TO 30 DEGREE RANGE. SATURDAY THROUGH SUNDAY: THE SURFACE RIDGE SETTLES ACROSS THEN SOUTH OF OUR REGION THIS PERIOD... BENEATH THE PROGRESSIVE RIDGING ALOFT. RETURN FLOW AROUND THE LOW LEVEL RIDGE SHOULD HELP TEMPERATURES TO RETURN TO NEAR NORMAL BY SUNDAY. THERE IS QUITE A BIT OF DISAGREEMENT AMONG THE GFS/ECMWF FOR THE END OF THE WEEKEND THROUGH EARLY NEXT WEEK... AND AT THIS TIME WILL NOT MAKE ANY CHANGES TO THIS PORTION OF THE FORECAST. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 640 AM MONDAY... VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS TONIGHT... HOWEVER AN INCREASE IN LOW LEVELS WINDS THIS AFTERNOON AND CONTINUING THROUGH THIS EVENING MAY RAISE THE POTENTIAL FOR LOW LEVEL TURBULENCE. A COLD FRONT NOW POSITIONED FROM SRN OH ACROSS WRN KY TO NRN AR WILL SWING INTO AND THROUGH CENTRAL NC LATE THIS AFTERNOON INTO THIS EVENING. LIGHT AND VARIABLE SURFACE WINDS WILL BECOME BRIEFLY FROM THE SW BEFORE SHIFTING TO NW AFTER FRONTAL PASSAGE. A DEEPENING MIXED LAYER WILL TAP INTO AROUND 25 KT WINDS UP AT 4000-5000 FT AGL... AND WE COULD SEE SOME GUSTS NEAR 18-23 KTS BETWEEN 18Z AND 03Z AT ALL TAF SITES. CLOUD BASES ARE EXPECTED TO VARY FROM SCATTERED TO BROKEN FROM MIDDAY ONWARD... WHILE STEADILY LOWERING TO 4000 FT AGL. A FEW SPRINKLES OR VIRGA ARE POSSIBLE AS AN UPPER LEVEL JET STREAK NOSES INTO NC THIS AFTERNOON THEN QUICKLY MOVES OVERHEAD INTO TONIGHT... BUT IT SHOULD HAVE MINIMAL IMPACT AT THE GROUND GIVEN THE DRY ANTECEDENT SURFACE CONDITIONS. LOOKING AHEAD TO LATE TONIGHT ONWARD: A STRONG MID LEVEL DISTURBANCE WILL DROP INTO THE REGION FROM THE NW... BRINGING ANOTHER SHOT AT CEILINGS AROUND 3000-4000 FT AGL FROM TUESDAY MORNING THROUGH MID-LATE AFTERNOON. RWI SHOULD SEE THE LOWEST CEILING AND MAY SEE A QUICK SPRINKLE OR FLURRY. OTHERWISE VFR CONDITIONS ARE ANTICIPATED. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...HARTFIELD SHORT TERM...VINCENT LONG TERM...VINCENT/MWS AVIATION...HARTFIELD nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1226 PM EST SUN NOV 16 2008 .SYNOPSIS... HIGH PRESSURE ALONG THE GULF COAST WILL BUILD INTO THE AREA TODAY AND MONDAY. UNSEASONABLY COLD AND DRY WEATHER WILL PERSIST THROUGH THE WEEK...WITH THE HIGH PRESSURE BEING REINFORCED MONDAY NIGHT AND AGAIN ON THURSDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 9 AM SUNDAY...1030 MB HIGH PRESSURE CENTERED OVER THE LOWER MISSISSIPPI RIVER VALLEY IS SPRAWLING ACROSS THE SOUTHERN HALF OF THE COUNTRY. STRONG COLD ADVECTION OVERNIGHT HAS PUSHED 850 MB TEMPS DOWN TO FREEZING CURRENTLY. DEEP MIXING UNDER BRIGHT SUNSHINE TODAY WILL WARM THOSE 850 MB READINGS SLIGHTLY BY AFTERNOON...AND SHOULD PUSH HIGHS INTO THE MID TO UPPER 50S TODAY. THIS IS STILL ON THE LOW SIDE OF THE MOS GUIDANCE AT MOST SITES BUT IS IN GOOD AGREEMENT WITH GFS/NAM/RUC FORECAST SOUNDINGS. CLEAR SKIES WILL CONTINUE THROUGH TONIGHT. WITH WINDS BECOMING LIGHT RADIATIONAL COOLING POTENTIAL WILL BECOME QUITE GOOD. TEMPERATURES WILL FALL TO AROUND FREEZING (OR BELOW) IN THE NORMALLY COLD SPOTS. WE WILL BE INVESTIGATING THE POTENTIAL FOR FROST ACROSS PORTIONS OF NEW HANOVER AND GEORGETOWN COUNTIES...THE ONLY TWO COUNTIES IN OUR FORECAST AREA WHERE THE GROWING SEASON OFFICIALLY CONTINUES. && .SHORT TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM SUNDAY...EAST COAST UPPER TROF AND DRY SFC HIGH PRESSURE WILL DOMINATE. H5 VORT MAX DIVING SE OUT OF CANADA WILL MOVE OFF THE MID-ATLANTIC COAST MONDAY NIGHT...OPENING THE DOOR FOR STRONG CAA THAT WILL PERSIST INTO TUESDAY. WELL-MIXED BOUNDARY LAYER WILL KEEP TEMPS FROM BOTTOMING OUT MONDAY NIGHT...BUT WILL ONLY ALLOW FOR MINIMAL RECOVERY DURING THE DAY ON TUESDAY. LOW-LEVEL THICKNESS PATTERN ON ITS OWN WOULD SUGGEST MAX TEMPS ONLY IN THE LOWER 40S...BUT DO RECALL THAT IN ANOTHER RECENT COLD OUTBREAK TEMPS WERE ABOUT A CATEGORY WARMER THAN THICKNESS SCHEMES HAD SUGGESTED. THEREFORE WENT WITH MID/UPPER 40S...WHICH IS STILL ABOUT A CATEGORY BELOW GUIDANCE. THE DEEP MIXING WILL KEEP WINDS UP IN THE 15-20MPH RANGE WITH GUSTS AROUND 25MPH FOR MOST OF THE DAY. DEWPOINTS WILL ALSO MIX DOWN INTO THE TEENS...BUT ANY FIRE WX CONCERNS SHOULD BE MITIGATED BY THE COLD TEMPERATURES. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 3 AM SUNDAY...EXPECT COLD AND DRY CONDITIONS THRU THE PERIOD AS A STRONG EAST COAST UPPER TROF WILL DOMINATE. SPRAWLING CANADIAN HIGH PRESSURE WILL BUILD FROM THE PLAINS TUE NIGHT AND WEDNESDAY...WITH ANOTHER MOISTURE-STARVED CLIPPER IN THE NW FLOW TO REINFORCE THE COLD AIR BY THURSDAY NIGHT. EVEN THO THE UPPER PATTERN FLATTENS OUT BY SATURDAY...1034MB HIGH PRESSURE OVER THE MID-ATLANTIC STATES WILL BE SLOW TO MODIFY. TUESDAY NIGHT WILL BE THE COLDEST NIGHT...WITH MID-UPPER 20S EXPECTED ACROSS MOST OF THE CWA. THIS SHOULD EVEN BE ENOUGH TO FINALLY END THE GROWING SEASON IN NEW HANOVER AND GEORGETOWN COUNTIES...THE ONLY TWO THAT MISSED OUT ON THE HARD FREEZE AT THE END OF OCTOBER. THERMAL TROF LIFTS OUT ON WEDNESDAY BUT THE DEGREE OF RECOVERY IS IN QUESTION. PROGGED LOW-LEVEL THICKNESSES AND 925MB TEMPS ONLY REBOUNDING TO 0C BY 00Z THU SUGGEST THAT EVEN 50 WILL BE A STRUGGLE. FRIDAY ALSO PROMISES TO BE WELL BELOW NORMAL...AND CURRENT FORECAST HIGHS IN THE LOWER/MID 50S ARE ABOUT A CATEGORY BELOW EXTENDED GFS MOS. OTHERWISE GUIDANCE TEMPS DO A GOOD JOB OF CONVEYING WEATHER MORE BECOMING OF JANUARY THAN NOVEMBER. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... NO CHANGES TO THE PREVIOUS SET OF TAFS WITH VFR CONDITIONS THROUGH THE FORECAST PERIOD. GUSTY WEST NORTHWEST WINDS WILL DIMINISH LATE THIS AFTERNOON...WITH LIGHT WINDS OVERNIGHT AND MONDAY. OUTLOOK THROUGH FRIDAY...A COLD DRY PATTERN IS FORECAST THROUGH FRIDAY WITH VFR CONDITIONS EXPECTED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 9 AM SUNDAY...COLD HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH TONIGHT WITH NORTHWEST WINDS. SPEEDS ARE AT THEIR PEAK CURRENTLY AND SHOULD DIMINISH THROUGH THE DAY AS THE TIGHTEST PORTION OF THE PRESSURE GRADIENT COINCIDENT WITH THE HEART OF THE COLD ADVECTION PUSHES OFFSHORE. THE SMALL CRAFT ADVISORY WILL BE ALLOWED TO EXPIRE ON SCHEDULE LATER THIS MORNING AS SEAS DIMINISH BELOW 6 FT AND WINDS FALL BELOW 25 KT. SHORT TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM SUNDAY...WEAK HIGH PRESSURE RIDGING ACROSS THE WATERS FROM THE GULF COAST STATES MONDAY...WILL TRANSLATE TO BENIGN WESTERLY FLOW. A PAIR OF DISTURBANCES IN NW FLOW ALOFT WILL INITIATE THE CAA SURGE MONDAY NIGHT...WITH NW WINDS KICKING UP TO SCA LEVELS BY DAYBREAK TUESDAY AND REMAINING THERE FOR MOST OF THE DAY. CURRENT FORECAST IS 20-25 KT...BUT I AM CONCERNED THAT IS NOT STRONG ENOUGH GIVEN THAT THE GFS SHOWS 25-30 KT THRU A DEEP MIXED LAYER. NAM WIND FIELD IS NOT QUITE AS STRONG...BUT SOLIDLY IN THAT 20-25KT RANGE. SEA GROWTH WILL BE LIMITED BY A TRAJECTORY THAT IS ALMOST PERFECTLY OFFSHORE. HAVE ONLY GONE FOR 6 FT SEAS AT FRYING PAN BUOY ON TUESDAY...AND 3-5 FT SHOULD COVER IT WITHIN 20NM. LONG TERM /TUESDAY NIGHT THROUGH THURSDAY/... AS OF 3 AM SUNDAY...HIGH PRESSURE WILL REMAIN TO OUR WEST TUE NIGHT AND WED...RESULTING IN GRADUALLY DIMINISHING NW WINDS. BY WED NIGHT THE HIGH BEGINS TO MODIFY OVER THE DEEP SOUTH...ALLOWING WIND DIRECTION TO BACK TO WEST. RETURN FLOW WILL PICK UP ON THURSDAY AHEAD OF THE NEXT CLIPPER...WITH THE MAIN QUESTION BEING HOW MUCH THE SPEEDS WILL INCREASE. MIXING WILL BE SHALLOW...BUT THE AIR MASS IS COLD ENOUGH THAT IT SHOULD AT LEAST BE DECENT. FOR NOW WILL CRANK UP A SOLID 15 KT AHEAD OF THE FRONT. SEAS WILL SUBSIDE TO 2-3 FT THRU MUCH OF THE PERIOD...BUT WILL START TO BUILD AGAIN THURSDAY AS WINDS PICK BACK UP. ANY CAA SURGE WITH THE NEXT SYSTEM WILL HOLD OFF UNTIL AFTER THE VALID PERIOD OF THIS CWF. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...RAS LONG TERM...RAS AVIATION...43 nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 648 PM EST MON NOV 17 2008 .SYNOPSIS... COLDER NORTHWEST FLOW AND LOW LEVEL MOISTURE WITH SIGNIFICANT UPSLOPE SNOW SHOWERS TONIGHT AND TUESDAY. MORE TRANQUIL FOR WEDNESDAY. COLD FRONT PASSES THURSDAY. && .NEAR TERM /THROUGH TUESDAY/... SNOW SHOWERS ASSOCIATED WITH SFC LOW PRESSURE CENTER WILL CONTINUE THRU TONIGHT AS THE SYSTEM MOVES EAST. AFTER THE LOW MOVES EAST... COLD ADVECTION UPSLOPE FLOW COMMENCES LATER...PERSISTS THROUGH TUE. NAM/GFS/RUC SHOWING DESCENT OMEGA WITHIN DENDRITE ZONE SPREADING NORTHWEST TO SOUTHEAST TONIGHT. THE NAM SOLUTION SHOWS A FEATURE MORE CONGRUENT WITH A MOISTURE PLUME FROM LAKE MICHIGAN TO AFFECT THE AREA OVERNIGHT...SPREADING FROM SOUTHEAST OH...SOUTHEAST INTO FAYETTE...NICHOLAS COUNTIES. PREVIOUS POPS/WX GRIDS LOOK REPRESENTATIVE FOR THE UPSLOPE EVENT. HOWEVER...INCREASE SNOW AMOUNTS OVER THE EASTERN MOUNTAINS FOR AND ENHANCED UPSLOPE EVENT EXPECTED WITH GOOD FORCING ALOFT. ALSO... INCREASE POPS ALONG THE AFOREMENTIONED MOIST PLUME FROM LAKE MICHIGAN. CONSEQUENTLY...HAVE EXPANDED THE WINTER STORM WARNING TO INCLUDE NICHOLAS COUNTY FOR NOW...AND EXPANDED THE WINTER WEATHER ADVISORY TO INCLUDE TYLER AND DODDRIDGE AS WELL. FOR LOWS TONIGHT...GUIDANCE SHOWING SIMILAR NUMBERS. HAVE GONE WITH THE SLIGHTLY LOWER MET GENERALLY IN THE MID 20S LOWLANDS...BUT AROUND 10F HIGHEST RIDGES. HIGHS FOR TUESDAY CODED IN THE LOWER 30S LOWLANDS AND IN THE 10S HIGHER ELEVATIONS PER H850 TEMPS DOWN TO -10C TO -12C PER NAM/GFS/SREF MODELS. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... DEEP UPPER LEVEL TROUGH WILL PUSH EAST...LEAVING THE CENTRAL APPALACHIANS IN NORTHWEST FLOW ALOFT. HEIGHTS WILL MODERATE SOMEWHAT...AND WARM FRONT WILL BRING SOME WEAK WARM AIR ADVECTION...BUT WILL NOT EVEN BE ABLE TO BRING US BACK TO NORMAL DAYTIME HIGHS. THE WARM FRONT DOES NOT HAVE MUCH ENERGY OR MOISTURE WITH IT...AND WILL JUST BRIEFLY SEND SOME MID LEVEL CLOUDS THROUGH THE NORTHERN HALF OF THE CWA. A COLD FRONT WILL FOLLOW FOR TUESDAY. LIKE A SIMILAR SCENARIO LAST WEEK...NAM QPF IS LACKING WITH THIS SYSTEM WHILE SREF PROBABILITIES SHOW THE HIGHER ELEVATIONS RECEIVING PRECIPITATION...MORE SO BEHIND THE FRONT. FELT THIS WAS MORE REALISTIC...AND WENT AS FAR AS TO GO LIKELY FOR A BRIEF PERIOD OF TIME IN THE NORTHEAST MOUNTAINS. WILL NEED TO WATCH THE OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT. SKY GRIDS DEPICT THE END OF THE UPSLOPE IN THE MOUNTAINS...AND THEN THE CLOUD COVER FROM THE WARM FRONT ARRIVES NEARLY SIMULTANEOUSLY. WITH SNOW ON THE GROUND...A PERIOD OF TIME WHERE THE SKY CLEARS IN BETWEEN THOSE TWO FEATURES WOULD WARRANT A DROP IN THESE TEMPERATURES. WENT OPTIMISTIC...WHICH STILL CARRIES VERY COLD OVERNIGHT LOWS. && .LONG TERM /THURSDAY THROUGH MONDAY/... STILL RUNNING WITH THE ECMWF FOR THE LONG TERM...WHICH STRESSES THE COOL/COLD PATTERN THROUGH THE BEGINNING OF THE WEEKEND. ECMWF AND GFS DIFFER CONSIDERABLY AFTER THIS TIME...WHERE A PANHANDLE LOW DEVELOPS AND COULD BRING WARM AIR ADVECTION FOR THE BEGINNING OF NEXT WEEK...WHILE THE GFS DROPS ANOTHER COLD FRONT THROUGH THE LAKES...WITH A REINFORCING DROP TO THE 500HPA HEIGHTS. AS THE GFS SEEMS TO BE INCONSISTENT FROM RUN TO RUN...AM MORE INCLINED TO ROLL WITH THE STEADIER ECMWF. CONFIDENCE IS LOW IN THE FORECAST BEYOND SUNDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VARIABLE CONDITIONS IN SNOW SHOWERS THROUGH 18Z TUESDAY...WITH SNOW SHOWERS DECREASING IN AREAL COVERAGE 18-00Z ESPECIALLY HTS-CRW-PKB VCNTY. CEILINGS MAINLY 1 TO 2 THSD FT AND VSBY AOB 3 MILES IN SNOW SHOWERS. CEILINGS AROUND 2 TO 3 THSD ACROSS LOWLANDS OUTSIDE OF SNOW SHOWERS...BUT STILL AROUND 1 TO 2 THSD FT ACROSS MOUNTAINS. AVIATION OUTLOOK /BEYOND 00Z WEDNESDAY/...NO SIGNIFICANT WEATHER. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TUESDAY NIGHT FOR WVZ037>040-046-047. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TUESDAY NIGHT FOR WVZ011-020-027-028-030>032-035-036. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...26/ARJ NEAR TERM...ARJ SHORT TERM...26 LONG TERM...26 AVIATION...KTB oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 348 PM EST MON NOV 17 2008 .SYNOPSIS... SFC LOW PRESSURE CENTER THRU TONIGHT. UPPER SYSTEMS PRODUCES A SIGNIFICANT UPSLOPE SNOW SHOWERS TONIGHT AND TUESDAY. COLD FRONT PASSES THURSDAY. HIGH PRESSURE FOR THE WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... SNOW SHOWERS ASSOCIATED WITH SFC LOW PRESSURE CENTER WILL CONTINUE THRU TONIGHT AS THE SYSTEM MOVES EAST. AFTER THE LOW MOVES EAST... COLD ADVECTION UPSLOPE FLOW COMMENCES LATER...PERSISTS THROUGH TUE. NAM/GFS/RUC SHOWING DESCENT OMEGA WITHIN DENDRITE ZONE SPREADING NORTHWEST TO SOUTHEAST TONIGHT. THE NAM SOLUTION SHOWS A FEATURE MORE CONGRUENT WITH A MOISTURE PLUME FROM LAKE MICHIGAN TO AFFECT THE AREA OVERNIGHT...SPREADING FROM SOUTHEAST OH...SOUTHEAST INTO FAYETTE...NICHOLAS COUNTIES. PREVIOUS POPS/WX GRIDS LOOK REPRESENTATIVE FOR THE UPSLOPE EVENT. HOWEVER...INCREASE SNOW AMOUNTS OVER THE EASTERN MOUNTAINS FOR AND ENHANCED UPSLOPE EVENT EXPECTED WITH GOOD FORCING ALOFT. ALSO... INCREASE POPS ALONG THE AFOREMENTIONED MOIST PLUME FROM LAKE MICHIGAN. CONSEQUENTLY...HAVE EXPANDED THE WINTER STORM WARNING TO INCLUDE NICHOLAS COUNTY FOR NOW...AND EXPANDED THE WINTER WEATHER ADVISORY TO INCLUDE TYLER AND DODDRIDGE AS WELL. FOR LOWS TONIGHT...GUIDANCE SHOWING SIMILAR NUMBERS. HAVE GONE WITH THE SLIGHTLY LOWER MET GENERALLY IN THE MID 20S LOWLANDS...BUT AROUND 10F HIGHEST RIDGES. HIGHS FOR TUESDAY CODED IN THE LOWER 30S LOWLANDS AND IN THE 10S HIGHER ELEVATIONS PER H850 TEMPS DOWN TO -10C TO -12C PER NAM/GFS/SREF MODELS. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...DEEP UPPER LEVEL TROUGH WILL PUSH EAST...LEAVING THE CENTRAL APPALACHIANS IN NORTHWEST FLOW ALOFT. HEIGHTS WILL MODERATE SOMEWHAT...AND WARM FRONT WILL BRING SOME WEAK WARM AIR ADVECTION...BUT WILL NOT EVEN BE ABLE TO BRING US BACK TO NORMAL DAYTIME HIGHS. THE WARM FRONT DOES NOT HAVE MUCH ENERGY OR MOISTURE WITH IT...AND WILL JUST BRIEFLY SEND SOME MID LEVEL CLOUDS THROUGH THE NORTHERN HALF OF THE CWA. A COLD FRONT WILL FOLLOW FOR TUESDAY. LIKE A SIMILAR SCENARIO LAST WEEK...NAM QPF IS LACKING WITH THIS SYSTEM WHILE SREF PROBABILITIES SHOW THE HIGHER ELEVATIONS RECEIVING PRECIPITATION...MORE SO BEHIND THE FRONT. FELT THIS WAS MORE REALISTIC...AND WENT AS FAR AS TO GO LIKELY FOR A BRIEF PERIOD OF TIME IN THE NORTHEAST MOUNTAINS. WILL NEED TO WATCH THE OVERNIGHT LOW TEMPERATURES TUESDAY NIGHT. SKY GRIDS DEPICT THE END OF THE UPSLOPE IN THE MOUNTAINS...AND THEN THE CLOUD COVER FROM THE WARM FRONT ARRIVES NEARLY SIMULTANEOUSLY. WITH SNOW ON THE GROUND...A PERIOD OF TIME WHERE THE SKY CLEARS IN BETWEEN THOSE TWO FEATURES WOULD WARRANT A DROP IN THESE TEMPERATURES. WENT OPTIMISTIC...WHICH STILL CARRIES VERY COLD OVERNIGHT LOWS. && .LONG TERM /THURSDAY THROUGH MONDAY/... STILL RUNNING WITH THE ECMWF FOR THE LONG TERM...WHICH STRESSES THE COOL/COLD PATTERN THROUGH THE BEGINNING OF THE WEEKEND. ECMWF AND GFS DIFFER CONSIDERABLY AFTER THIS TIME...WHERE A PANHANDLE LOW DEVELOPS AND COULD BRING WARM AIR ADVECTION FOR THE BEGINNING OF NEXT WEEK...WHILE THE GFS DROPS ANOTHER COLD FRONT THROUGH THE LAKES...WITH A REINFORCING DROP TO THE 500HPA HEIGHTS. AS THE GFS SEEMS TO BE INCONSISTENT FROM RUN TO RUN...AM MORE INCLINED TO ROLL WITH THE STEADIER ECMWF. CONFIDENCE IS LOW IN THE FORECAST BEYOND SUNDAY. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... A SFC LOW PRESSURE CENTER RESPONSIBLE FOR SNOW SHOWERS TODAY WILL TRACK EAST TONIGHT. SNOWFALL WILL PRODUCE IFR CEILINGS DOWN TO ABOUT 600FT AND VISIBILITY DOWN TO 3/4SM WITH THE HEAVIEST SNOW...1500FT AND 2SM FOR LIGHTER SNOW. RADAR IMAGES SHOW SNOW SHOWERS ACROSS CENTRAL WV OVER CRW...MOVING EAST TO AFFECT BKW THROUGH AT LEAST 23Z. ONCE THE SFC LOW MOVES EAST TONIGHT...A STRONG UPPER TROF WILL SWING SOUTHEAST ACROSS THE AREA ENHANCING SNOW SHOWERS...AND PROMOTING UPSLOPE SNOW UNDER NORTHWEST FLOW MAINLY OVER THE EASTERN MOUNTAINS OVERNIGHT INTO TUESDAY. THESE CONDITIONS WILL PRODUCE IFR/LIFR CONDITIONS OVERNIGHT AND TUESDAY MORNING. OCCASIONAL WIND GUSTS FROM W TO NW FLOW WILL CONTINUE THROUGH TONIGHT IN THE WAKE OF THE LOW AND COLD FRONT. AVIATION OUTLOOK /BEYOND 18Z TUESDAY/...IFR LIKELY AT TIMES IN VARIABLE CONDITIONS IN SNOW SHOWERS MAINLY CKB-CRW AND E INTO MOUNTAINS INCLUDING EKN AND BKW INTO TUESDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL MIDNIGHT EST TUESDAY NIGHT FOR WVZ037>040-046-047. WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TUESDAY NIGHT FOR WVZ011-020-027-028-030>032-035-036. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...26/ARJ NEAR TERM...ARJ SHORT TERM...26 LONG TERM...26 AVIATION...ARJ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 1036 AM CST SUN NOV 16 2008 .UPDATE... COLD AIR ADVECTION IS UNDER WAY IN THE NORTHEAST CORNER OF THE CWA WHERE KETH/KVVV/K8D3 HAVE REMAINED STEADY TEMPERATURE WISE. WITH AN ABUNDANCE OF CLOUDS UPSTREAM...EXPECT THIS AREA HAS STOPPED WARMING. HAVE DELAYED THE MENTION OF SNOW A FEW HOURS AS THERE IS NOT MUCH SHOWING UP ON RADAR. AS FOR MY WESTERN COUNTIES...HAVE EXTENDED THE AREA OF LIGHT RAIN TO THE MISSOURI RIVER. HOWEVER WITH A NINE DEGREE TEMP/DEW POINT SPREAD...EXPECT VERY LITTLE RAIN FALL TO REACH THE GROUND. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH TUESDAY FORECAST CHALLENGES INCLUDE MAINLY TEMPERATURE ADVECTION PATTERN OVER THE NEXT COUPLE OF DAYS. WELL...FOR SOMETHING LIKE THE THIRD TIME IN THE PAST SEVEN DAYS...A NON-DIURNAL TEMPERATURE TREND IS ONGOING ACROSS THE FORECAST AREA...WITH WINDS SWITCHING FROM SOUTH AHEAD OF A WARM FRONT TO WEST BEHIND THE WARM FRONTAL PASSAGE. ACCOMPANYING THIS SHIFT IN WIND DIRECTION IS WARM AIR ADVECTION...AT A PREMIUM. FOR EXAMPLE...AT 7 PM CST LAST EVENING KPIR WAS SITTING AT 35 DEGREES. ALONG CAME THE WARM FRONT AND THE WIND SHIFT AND THE TEMPERATURE THERE ROSE TO 44 DEGREES IN THE PAST THREE HOURS. THIS WARM FRONT IS ATTACHED TO A SURFACE LOW CENTER OVER SOUTHEAST NORTH DAKOTA...SO THE ATTENDANT COLD FRONT WHICH WILL BACK DOOR ITS WAY ACROSS THE FORECAST AREA TODAY IS NOT ALL THAT FAR AWAY FROM THE CWA AT THIS TIME. THIS TRANSITION INTO CAA BEHIND THE COLD FRONTAL PASSAGE IS ALSO DENOTED BY THE 925HPA THERMAL PROGS IN THE RUC MODEL THIS MORNING. RIGHT ON THE HEELS OF THE SURFACE LOW AND ON THE NOSE OF THE STRONGEST CAA THIS AFTERNOON SOME SNOW SHOWERS COULD WORK THEIR WAY DOWN INTO EXTREME NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA. THERE IS ALSO A 110 KNOT UPPER LEVEL JET STREAK WORKING SOUTH ACROSS THE DAKOTAS TODAY...WHICH MAY ENHANCE A BAROCLINIC ZONE /700HPA/ THAT WILL BE IN PLACE TODAY ACROSS WESTERN AND CENTRAL SOUTH DAKOTA. AS SUCH...BASICALLY JUST TWEAKED SOME SNOW SHOWERS/FLURRIES MENTION FOR THIS AFTERNOON/TONIGHT ACROSS FAR NE SODAK AND WC MN...AND LEFT THE SLT CHANCE OF LIGHT RAIN GOING ACROSS THE SOUTHWESTERN-MOST FORECAST ZONES. THE REMAINDER OF THE FORECAST LOOKS TO BE A DRY FORECAST FOR THE TIME BEING...WITH THE LOW LEVEL CAA SEQUENCE LASTING FROM TODAY THROUGH THE FIRST HALF OF MONDAY BEFORE GRADUALLY TRANSITIONING INTO A LOW LEVEL WAA PATTERN LATE MONDAY NIGHT AND DURING THE DAY ON TUESDAY WHEN THE NEXT UPPER WAVE ENCROACHING THE REGION DRAGS ITS WARM FRONT THROUGH THE FORECAST AREA. POSSIBLY ANOTHER NON-DIURNAL TEMPERATURE TREND SCENARIO DEVELOPING. NO CHANGES OF SUBSTANCE WERE MADE TO INHERITED MAX/MIN TEMPS WITH THIS FORECAST PACKAGE...WITH TUESDAY STILL LOOKING LIKE THE WARMEST DAY IN THE SHORT TERM. .LONG TERM...00Z WEDNESDAY THROUGH SATURDAY. MAIN FCST CHALLENGE FACING THE EXTENDED DEALS WITH TEMPS THROUGH THE PERIOD. EXTENDED STARTS OFF WITH BUILDING RIDGE TO THE WEST...WITH LONGWAVE TROF LOCATED EAST OF THE CWA. NW FLOW REMAINS OVER THE REGION. CURRENTLY DRY FCST IS IN PLACE ACROSS THE AREA THROUGH NEXT WEEKEND...AND THIS STILL LOOKS VALID. FIRST CLIPPER SYSTEM TO DROP THROUGH THE AREA DURING THE DAY WEDNESDAY LOOKS TO KEEP ALL PCPN NORTH OF THE AREA. HIGH PRESSURE THEN BUILDS INTO THE NORTHERN PLAINS THROUGH THE FIRST OF THE WEEKEND...BEFORE ANOTHER LOW PRESSURE SYSTEM SLIDES ALONG THE INTERNATIONAL BORDER DURING NEXT WEEKEND. TEMP WISE...WEDNESDAY MAX T GRIDS COULD BE DIFFICULT TO NAIL DOWN. THE NAM KEEPS THE COLDER AIR BOTTLED UP FURTHER TO THE NORTH WHEN COMPARED TO THE GFS/EC...WITH THE EC BEING THE COOLEST OF THE THREE. THE GFS/EC DO AGREE ON A CAA PATTERN TAKING PLACE DURING THE DAY WEDNESDAY...BUT THE STRENGTH OF CAA IS WHERE DIFFICULTIES ARISE. FOR NOW...HAVE TRENDED UP THE SOUTHERN PORTIONS OF THE CWA BY A FEW DEGREES...BUT KEPT THE COOLISH TEMPS IN PLACE ACROSS THE NORTHERN COUNTIES AS FRONT SHOULD PASS THROUGH FAIRLY EARLY. MAY END UP BEING A "STEADY OR SLOWLY FALLING" DAY WITH REGARDS TO HIGHS...BUT TOO FAR OUT TO INSERT THAT MUCH DETAIL. BY THURSDAY...THE GFS SHOWS A 1035MB HIGH OVER THE REGION...WITH THE EC SHOWING A 1040MB HIGH. COOL CONDITIONS ALREADY IN PLACE FOR THURSDAY. DID BOLSTER CLOUDS JUST A BIT...AS SOME LOW CLOUDS MAY BE TRAPPED UNDER INVERSION. && .AVIATION... WEAK CLIPPER SYSTEM MOVING ACROSS THE UPPER MIDWEST WILL RESULT IN CONTINUED MVFR/LOW VFR CONDITIONS AT KATY AND KABR FOR THE REST OF TODAY. FARTHER WEST WILL SEE MAINLY VFR CONDITIONS AT KPIR AND KMBG WITH BRIEF MVFR CONDITIONS POSSIBLE. LOWER CLOUDS WILL BEGIN TO DISSIPATE AFTER 00Z MONDAY AS SYSTEM EXITS AREA...WITH WIDESPREAD VFR CONDITIONS EXPECTED ON MONDAY. NORTHWEST WINDS OF 15 TO 20 KNOTS WITH GUSTS UP TO 30 KNOTS EXPECTED TO PERSIST TODAY BEFORE DIMINISHING AROUND 00Z MONDAY. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...SD SHORT TERM...DORN LONG TERM...HINTZ AVIATION...ZELTWANGER WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 309 AM CST SUN NOV 16 2008 .SHORT TERM...TODAY THROUGH TUESDAY FORECAST CHALLENGES INCLUDE MAINLY TEMPERATURE ADVECTION PATTERN OVER THE NEXT COUPLE OF DAYS. WELL...FOR SOMETHING LIKE THE THIRD TIME IN THE PAST SEVEN DAYS...A NON-DIURNAL TEMPERATURE TREND IS ONGOING ACROSS THE FORECAST AREA...WITH WINDS SWITCHING FROM SOUTH AHEAD OF A WARM FRONT TO WEST BEHIND THE WARM FRONTAL PASSAGE. ACCOMPANYING THIS SHIFT IN WIND DIRECTION IS WARM AIR ADVECTION...AT A PREMIUM. FOR EXAMPLE...AT 7 PM CST LAST EVENING KPIR WAS SITTING AT 35 DEGREES. ALONG CAME THE WARM FRONT AND THE WIND SHIFT AND THE TEMPERATURE THERE ROSE TO 44 DEGREES IN THE PAST THREE HOURS. THIS WARM FRONT IS ATTACHED TO A SURFACE LOW CENTER OVER SOUTHEAST NORTH DAKOTA...SO THE ATTENDANT COLD FRONT WHICH WILL BACK DOOR ITS WAY ACROSS THE FORECAST AREA TODAY IS NOT ALL THAT FAR AWAY FROM THE CWA AT THIS TIME. THIS TRANSITION INTO CAA BEHIND THE COLD FRONTAL PASSAGE IS ALSO DENOTED BY THE 925HPA THERMAL PROGS IN THE RUC MODEL THIS MORNING. RIGHT ON THE HEELS OF THE SURFACE LOW AND ON THE NOSE OF THE STRONGEST CAA THIS AFTERNOON SOME SNOW SHOWERS COULD WORK THEIR WAY DOWN INTO EXTREME NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA. THERE IS ALSO A 110 KNOT UPPER LEVEL JET STREAK WORKING SOUTH ACROSS THE DAKOTAS TODAY...WHICH MAY ENHANCE A BAROCLINIC ZONE /700HPA/ THAT WILL BE IN PLACE TODAY ACROSS WESTERN AND CENTRAL SOUTH DAKOTA. AS SUCH...BASICALLY JUST TWEAKED SOME SNOW SHOWERS/FLURRIES MENTION FOR THIS AFTERNOON/TONIGHT ACROSS FAR NE SODAK AND WC MN...AND LEFT THE SLT CHANCE OF LIGHT RAIN GOING ACROSS THE SOUTHWESTERN-MOST FORECAST ZONES. THE REMAINDER OF THE FORECAST LOOKS TO BE A DRY FORECAST FOR THE TIME BEING...WITH THE LOW LEVEL CAA SEQUENCE LASTING FROM TODAY THROUGH THE FIRST HALF OF MONDAY BEFORE GRADUALLY TRANSITIONING INTO A LOW LEVEL WAA PATTERN LATE MONDAY NIGHT AND DURING THE DAY ON TUESDAY WHEN THE NEXT UPPER WAVE ENCROACHING THE REGION DRAGS ITS WARM FRONT THROUGH THE FORECAST AREA. POSSIBLY ANOTHER NON-DIURNAL TEMPERATURE TREND SCENARIO DEVELOPING. NO CHANGES OF SUBSTANCE WERE MADE TO INHERITED MAX/MIN TEMPS WITH THIS FORECAST PACKAGE...WITH TUESDAY STILL LOOKING LIKE THE WARMEST DAY IN THE SHORT TERM. .LONG TERM...00Z WEDNESDAY THROUGH SATURDAY. MAIN FCST CHALLENGE FACING THE EXTENDED DEALS WITH TEMPS THROUGH THE PERIOD. EXTENDED STARTS OFF WITH BUILDING RIDGE TO THE WEST...WITH LONGWAVE TROF LOCATED EAST OF THE CWA. NW FLOW REMAINS OVER THE REGION. CURRENTLY DRY FCST IS IN PLACE ACROSS THE AREA THROUGH NEXT WEEKEND...AND THIS STILL LOOKS VALID. FIRST CLIPPER SYSTEM TO DROP THROUGH THE AREA DURING THE DAY WEDNESDAY LOOKS TO KEEP ALL PCPN NORTH OF THE AREA. HIGH PRESSURE THEN BUILDS INTO THE NORTHERN PLAINS THROUGH THE FIRST OF THE WEEKEND...BEFORE ANOTHER LOW PRESSURE SYSTEM SLIDES ALONG THE INTERNATIONAL BORDER DURING NEXT WEEKEND. TEMP WISE...WEDNESDAY MAX T GRIDS COULD BE DIFFICULT TO NAIL DOWN. THE NAM KEEPS THE COLDER AIR BOTTLED UP FURTHER TO THE NORTH WHEN COMPARED TO THE GFS/EC...WITH THE EC BEING THE COOLEST OF THE THREE. THE GFS/EC DO AGREE ON A CAA PATTERN TAKING PLACE DURING THE DAY WEDNESDAY...BUT THE STRENGTH OF CAA IS WHERE DIFFICULTIES ARISE. FOR NOW...HAVE TRENDED UP THE SOUTHERN PORTIONS OF THE CWA BY A FEW DEGREES...BUT KEPT THE COOLISH TEMPS IN PLACE ACROSS THE NORTHERN COUNTIES AS FRONT SHOULD PASS THROUGH FAIRLY EARLY. MAY END UP BEING A "STEADY OR SLOWLY FALLING" DAY WITH REGARDS TO HIGHS...BUT TOO FAR OUT TO INSERT THAT MUCH DETAIL. BY THURSDAY...THE GFS SHOWS A 1035MB HIGH OVER THE REGION...WITH THE EC SHOWING A 1040MB HIGH. COOL CONDITIONS ALREADY IN PLACE FOR THURSDAY. DID BOLSTER CLOUDS JUST A BIT...AS SOME LOW CLOUDS MAY BE TRAPPED UNDER INVERSION. && .AVIATION... MVFR/LOW VFR CIGS ARE EXPECTED TO MOVE INTO THE KMBG AND KABR TERMINAL SITES BY 12Z...AS WEAK CLIPPER SYSTEM DROPS QUICKLY SE THROUGH THE AREA. LOOK FOR THOSE CIGS TO ADVECT INTO KPIR AND KATY BY 18Z. THE MVFR/LOW VFR CIGS WILL PERSIST THROUGH 00Z MONDAY BEFORE BEGINNING TO DISSIPATE. VSBYS SHOULD BE P6SM AT ALL TERMINAL SITES THROUGH 06Z MONDAY. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...DORN LONG TERM...HINTZ AVIATION...HINTZ WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 910 PM CST MON NOV 17 2008 .UPDATE... WEAK COLD FRONT NOW MOVING THROUGH THE I-20 CORRIDOR. HAVE UPDATED FORECAST TO INCLUDE SOME SLIGHTLY HIGHER NORTH/NORTHEAST WINDS BEHIND IT TONIGHT BASED ON UPSTREAM OBS/RUC FORECASTS. THIS WILL KEEP AIR MIXED UP WITH MIN TEMPS A LITTLE HIGHER THAN PREVIOUS NIGHTS. RAISED LOWS OVER THE WESTERN ZONES...OTHERWISE CHANGES WERE MAINLY COSMETIC. TR.92 && .AVIATION... 514 PM VFR THRU PERIOD. WIND SHIFT TO NORTH EXPECTED METROPLEX AROUND 02Z AND WACO 05Z. BY TUESDAY AFTN SFC RIDGE MOVES ON EAST AND FLOW WILL SWITCH BACK SOUTH. 84 && .PREV DISCUSSION... /ISSUED 200 PM CST MON NOV 17 2008/ SURFACE OBSERVATIONS THIS HOUR PLACE A COLD FRONT NEAR A LINE FROM LUBBOCK TO WICHITA FALLS TO JUST NORTH OF PARIS. TEMPERATURES ACROSS NORTH TEXAS ARE CURRENTLY IN THE 70S...WITH 50S AND 60S NOTED BEHIND THE FRONT. DEW POINT TEMPERATURES ARE VIRTUALLY THE SAME ON EITHER SIDE OF THE BOUNDARY. FRONTAL PASSAGE WILL OCCUR AFTER SUNSET FOR MOST OF THE REGION SO HIGH TEMPS WILL NOT BE AFFECTED MUCH. RADIATIONAL COOLING WILL NOT BE QUITE AS EFFECTIVE TONIGHT AS LAST NIGHT DUE TO SLIGHTLY HIGHER WIND SPEEDS. BY TOMORROW A COOLER AIRMASS WILL ARRIVE IN NORTH TEXAS...WITH HIGHS ONLY EXPECTED IN THE UPPER 50S TO MID 60S. SOUTH WINDS WILL RETURN WEDNESDAY ALLOWING AFTERNOON TEMPS TO INCREASE INTO THE LOWER 70S. INCREASING MOISTURE WILL ALSO HELP LOW TEMPS WEDNESDAY NIGHT/THURSDAY MORNING FROM DROPPING AS LOW AS PREVIOUS NIGHTS. MODELS INDICATE THAT A 1040 MB SURFACE HIGH WILL SLIDE SOUTH OUT OF CANADA ON THURSDAY BEHIND A STRONG COLD FRONT. THE ECMWF IS SLIGHTLY FASTER WITH THE RESULTANT FRONTAL PASSAGE THAN THE GFS. GIVEN THE DENSE NATURE OF THE AIRMASS...HAVE SIDED WITH THE ECMWF. IN ADDITION...THE GFS SEEMS TO BE HAVING TROUBLE RESOLVING THE SHALLOW COLD AIRMASS...AND THE RESULT HAS BEEN WIDE VARIATIONS IN TEMPERATURES FROM RUN TO RUN. THEREFORE HAVE FOLLOWED THE ENSEMBLE NUMBERS CLOSER THAN THE MAV MOS FOR THE LAST HALF OF THE FORECAST. NORTH TEXAS WILL STAY IN NORTHWEST/WEST FLOW ALOFT OVER THE WEEKEND. WEAK ISENTROPIC LIFT ALONG WITH ENERGY ASSOCIATED WITH A PASSING SHORTWAVE WILL PROVIDE A CHANCE FOR SHOWERS AND POSSIBLY A THUNDERSTORM SUNDAY. THE ECMWF INDICATES A BETTER CHANCE OF RAIN MONDAY AS A STRONG CLOSED LOW ROTATES INTO THE NORTHERN PLAINS... SENDING ANOTHER COLD FRONT OUR WAY. SH/13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 46 63 47 75 54 / 0 0 0 0 5 WACO, TX 40 65 45 73 54 / 0 0 0 0 5 PARIS, TX 38 57 38 68 47 / 0 0 0 0 10 DENTON, TX 40 62 44 74 49 / 0 0 0 0 5 MCKINNEY, TX 40 60 41 71 49 / 0 0 0 0 5 DALLAS, TX 46 61 47 72 53 / 0 0 0 0 5 TERRELL, TX 41 60 43 71 52 / 0 0 0 0 5 CORSICANA, TX 41 62 42 72 53 / 0 0 0 0 5 TEMPLE, TX 42 67 45 73 53 / 0 0 0 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 1243 PM EST SUN NOV 16 2008 .SYNOPSIS... A COLD AIRMASS WILL MOVE IN TONIGHT INTO EARLY NEXT WEEK. ANOTHER FRONT WILL BRING A REINFORCING SHOT OF COLD AIR IN BY TUESDAY. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... ANOTHER SHRTWV IN THE TROUGH WILL ROUND THROUGH WEST VA AND WESTERN VA THROUGH 18Z PER RUC13. KI16...PINEVILLE WEST VA WENT DOWN TO 1SM IN THESE SCATTERED BRIEF BURSTS OF SNOW ASSOCIATED WITH THE WAVE. A QUICK COATING COULD FALL IN NORTHERN MERCER SOUTHERN SUMMERS OVER THE NEXT FEW HRS. SNW SHWS BACK WEST MOVING IN MORE OF A WESTERLY FASHION AS H85 FLOW BECOMES ZONAL ALTHOUGH NOT QUITE ENOUGH RIDGING TO SHUT SNW SHWS DOWN IN WESTERN GREENBRIER. ANOTHER INCH OR TWO POSSIBLE ALONG THE HIGHEST PEAKS THERE...WITH ABOUT AN INCH ALONG THE HIGHEST PARTS OF SUMMER/MERCER COUNTY. BACK EAST...NOT MUCH OF THE SNWS SHWS IN THE FAR WEST WILL SURVIVE...PERHAPS JUST FLURRIES IN THE ROA/BCB/PSK/MKJ CORRIDOR. TEMPS NOT EXPECTED TO RISE MUCH TODAY...EXCEPT EAST OF THE BLUE RIDGE WITH INCREASING SUNSHINE AS THE NW FLOW CLOUD DECK ERODES WEST WITH SOME HEATING. MORNING SOUNDING SHOWS A THICK LAYER OF MOISTURE UNDER THE INVERSION...WHICH MEANS CLDS PROB WILL HANG TOUGH UNTIL INVERSION LOWERS A BIT TONIGHT. && .SHORT TERM /7 PM THIS EVENING THROUGH TUESDAY NIGHT/... EXPECTING ANOTHER SHORTWAVE TO DIG INTO THE ERN TROUGH MONDAY...BRINGING SOME SNOW SHOWER CHANCES TO THE WRN SLOPES WHILE THE EAST SEES DOWNSLOPING WINDS. GOING TO FOLLOW A 00Z GFS/21Z SREF BLEND THIS PERIOD. GFS SHOWING SOME MID/HIGH CLOUDS SPILLING IN FROM THIS SHORTWAVE INTO THE NC/VA PIEDMONT MONDAY. THE STRONGER SHORTWAVE WILL DING INTO THE CENTRAL APPS MON NIGHT WHICH WILL BRING THE BEST SHOT OF UPSLOPE SNOW SHOWERS. ATTM...COULD SEE UP TO 4 INCHES IN NRN GREENBRIER FROM MON AFTN-TUE AFTN. MAY HAVE TO SHOOT OUT AN ADVISORY IF THIS CONTINUES TO GO THE WAY THE MODELS PLAN IT OUT...BUT APPEARS WRN GREENBRIER IS THE ONLY AREA TO SEE IT HIGH ENOUGH TO HAVE ADVISORY ACCUMULATIONS. COLD ADVECTION CONTINUES IN ERNEST TUESDAY AS COLD HIGH PRESSURE SLOWLY BUILDS IN FROM THE WEST AND THE UPPER TROF STARTS TO DEPART. LOOKS LIKE UPSLOPE RH WILL BE DEEP ENOUGH FOR CONTINUED ACCUMULATING SNOWFALL ON THE WESTERN SLOPES INTO AFTERNOON BEFORE TAPERING OFF TUESDAY EVENING. THUS KEEPING AT LEAST LIKELY POPS WEST TUESDAY WITH ONLY FLURRIES TUESDAY EVENING. OTRW QUITE COLD TUE WITH MANY SPOTS OVER THE MOUNTAINS STAYING IN THE 30S FOR HIGHS WHILE SUN/DOWNSLOPE ALLOW FOR SOME 40S OUT EAST. COLDEST NIGHT OF THE SEASON SO FAR TUESDAY NIGHT GIVEN HIGH PRESSURE BUILDING OVERHEAD LATE AND SOME SNOW COVER FAR WEST. IF CLOUDS DO CLEAR EARLY ENOUGH APPEARS SOME MID/UPPER TEENS LIKELY FAR WEST WITH 20S ELSEWHERE. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... COLD HIGH PRESSURE WILL REMAIN OVER THE AREA WED RESULTING IN MAINLY SUNNY SKIES BUT CHILLY TEMPS WITH LOWS AGAIN IN THE TEENS ACROSS THE WEST THU MORNING. A PERSISTENT UPPER LEVEL RIDGE ACROSS WESTERN CONUS WILL CONTINUE INTO THE WEEKEND ALLOWING FOR ADDITIONAL NORTHERN STREAM NORTHWEST FLOW LOW PRESSURE SYSTEMS/TROUGHS TO HEAD INTO NEW ENGLAND AND MID-ATLANTIC STATES. FOR THE AREA...THIS WILL RESULT IN TEMPERATURES REMAINING BELOW NORMAL ESPCLY EARLY IN THE PERIOD WITH YET ANOTHER SURGE OF COLD AIR AND ASSOCIATED UPSLOPE SNOW SHOWERS THU INTO THU NIGHT. REPRIEVE IN COLD ADVECTION WILL BE SHORT AS HIGH PRESSURE SETTLES IN FRIDAY AHEAD OF YET ANOTHER S/W SET TO DIVE INTO THE REGION FOR THE WEEKEND. THIS WILL BRING A RE-INFORCING SHOT OF COLD AIR ALONG WITH A FEW ADDED -SHSN ACROSS THE NW FOR EARLY IN THE WEEKEND. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... EXPECTING 3K TO 5K CLD DECK TO REMAIN IN THE KLWB/KBLF CORRIDOR FOR MUCH OF THE TAF PERIOD. WINDS CAN STILL GUST TO 30KT AT ALL TERMINALS EXCEPT KLWB THROUGH TODAY AND TONIGHT...BUT THE STRONGEST WINDS ARE PROBABLY OVER. ANOTHER SHRTWV DROPS INTO TH TROUGH BETWEEN 3Z-6Z TONIGHT BEFORE WAA ENSUES. ALTHOUGH PVA IS SUBTLE AT KLWB TONIGHT....MIGHT JUST BE ENOUGH FORCING FOR A FEW HOURS OF MVR SNOW SHS. THE OP GFS IS MORE BULLISH WITH THIS FEATURE...WITH MOISTURE BRIEFLY TOUCHING H7 IN THE TIME FRAME. CAA RETURNS WITH ANOTHER UPPER DISTURBANCE NEAR THE END OF THE TAF PERIOD WITH MORE PERSISTENT SNW SHS DEVELOPING MON AFTERNOON AND MONDAY NIGHT KLWB THEN KBLF. LOW PRESSURE DEVELOPING OFF THE NEW ENGLAND COAST TUES AND TUESDAY NIGHT DEEPENS THE EASTERN TROUGH SUCH THAT AN UPPER WAVE MAY ALLOW MVFR/IFR SNW SHWS TO PENETRATE AS FAR SOUTH AS THE KROA/KBCB/KPSK CORRIDOR WITH MORE GUSTY WINDS. MOUNTAIN SNW SHWS AND BOUTS OF MVFR/IFR VIS/CIG WILL PERSIST THROUGH THE WEEK KLWB/KBLF...WITH AT WORST MVFR CIGS AND SOME GUSTY WINDS OTHER TERMINALS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JJ/WP NEAR TERM...KM SHORT TERM...JH/WP LONG TERM...DS AVIATION...KM va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 328 PM CST MON NOV 17 2008 .SHORT TERM...TONIGHT AND TUESDAY... LATEST RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW A BROAD UPPER LEVEL RIDGE-TROUGH PATTERN FROM WEST TO EAST ACROSS NORTH AMERICA. MODEST SHORTWAVE CONTINUES TO DIVE WITHIN THE BACK SIDE OF THE UPPER TROUGH AS IT MAKES ITS WAY ACROSS NORTHERN WISCONSIN. DEEPER MOISTURE AND COLDER AIR ASSOCIATED WITH THE WAVE HAS HELPED PERSISTENT NNW OR NORTH LAKE EFFECT BANDS KEEP THEIR INTENSITY THROUGH MID-AFTERNOON. A COUPLE SURFACE TROUGHS HAVE BEEN EVIDENT ON RADAR AND THE SURFACE OBS WHICH HAVE ENHANCED THESE SNOW BANDS. ONE BAND DROPPED 1 TO 3 INCHES FROM VILAS THROUGH LINCOLN AND LANGLADE COUNTIES AS THE CONVERGENCE AXIS DROPPED SOUTH. ANOTHER CONVERGENCE AXIS HAS BEEN FEEDING AN ORGANIZED BAND ACROSS EASTER UPPER MICHIGAN AND HAS BEEN TRYING MOVE SW TOWARDS THE DOOR PENINSULA. OBVIOUSLY...LAKE EFFECT SNOW REMAINS THE MAIN FORECAST CONCERN. NORTH TO NNW LAKE EFFECT WILL CONTINUE THROUGH THE EVENING BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE TOWARDS THE LONGEVITY OF THE BANDS. IMPRESSIVE OVER-LAKE INSTABILITY WITH DELTA T/S AROUND 20C WILL BE COUNTERACTED BY INCOMING 850-700MB DRY (FALLING FROM 70 TO 40 PCT) AND INCREASINGLY ANTICYCLONIC FLOW. WAS ALSO THINKING THE VERY LOW DEWPOINT AIR OVER THE ARROWHEAD AND SOUTHERN ONTARIO (SURFACE DEWPOINTS RANGING FROM 0-7F) WOULD SLOW LAKE EFFECT SNOW DEVELOPMENT...BUT HAVENT SEEN ANY IMPACT AS OF YET. THE LONGER FETCHES AS A RESULT OF THE MORE NORTHERLY FLOW SEEM TO NEGATING THIS FACTOR UNLIKE YESTERDAY. BUT AS THE DRIER AIR WORKS INTO THE AREA...THE LAKE EFFECT SNOW WILL TAKE AWHILE TO WIND DOWN...SO HAVE EXTENDED THE ADVISORY FOR VILAS COUNTY THROUGH THE EVENING. THINK THAT AN ADDITIONAL 1 TO 2 INCHES WILL FALL DURING THE EVENING AND ANOTHER HALF INCH OVERNIGHT. OTHERWISE...WILL HAVE SNOW SHOWERS THIS AFTERNOON DIMINISHING TO FLURRIES THIS EVENING AS THE CONVERGENCE AXIS OVER WISCONSIN WASHES OUT AND WE LOSE THE DIURNAL HEATING. WILL HAVE TO WATCH TO SEE IF THE OTHER CONVERGENCE AXIS OVER EASTERN LAKE SUPERIOR MAKES IT TO THE DOOR PENINSULA...WHICH COULD DROP A QUICK HALF INCH TO INCH OF SNOW. MODEL DATA SUGGEST IT WILL WASH OUT BEFORE REACHING WASHINGTON ISLAND BUT HAVE INCLUDED LIGHT SNOW SHOWERS THROUGH THE NIGHT ANYWAY. LOWS FROM THE LOW TEENS WEST TO LOW 20S EAST. HIGH PRESSURE BUILDS INTO NE WISCONSIN TOMORROW WITH MASSIVE HEIGHT RISES UNDERWAY ALOFT. PERHAPS SOME DIURNAL CU WILL HANG ON OR DEVELOP WITHIN THE LINGERING COLD AIRMASS NEAR LAKE MICHIGAN DURING THE MORNING. WARM ADVECTION KICKS IN DURING THE AFTERNOON WITH MID-LEVEL CLOUD COVER INVADING THE STATE. HIGHS RANGING FROM THE UPPER 20S NW TO THE MIDDLE 30S SE. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY. THE CHANCE OF ANOTHER SIGNIFICANT LAKE EFFECT EVEN WEDNESDAY NIGHT AND THURSDAY AND WHETHER OR NOT WE WILL BE ON THE NORTHERN FRINGE OF A WINTER STORM SUNDAY NIGHT AND MONDAY ARE THE TWO MAIN CHALLENGES FOR THIS PERIOD. A SHORTWAVE TROUGH MOVING THROUGH ON WEDNESDAY MAY CREATE SUFFICIENT MID LEVEL MOISTURE AND LIFT TO PRODUCE SOME LIGHT FREEZING DRIZZLE IN THE NORTH. THEN ANOTHER PUSH OF COLD AIR POURS INTO THE REGION SETTING UP SCATTERED SNOW SHOWERS AND LAKE EFFECT SNOW WEDNESDAY NIGHT AND THURSDAY. THINK THERE COULD BE ANOTHER ADVISORY CRITERIA SNOW EVENT IN VILAS COUNTY...AS WINDS AND TEMPERATURES ALOFT ARE CLOSE TO WHAT WE HAVE HAD TODAY. THE EVENT FOR SUNDAY NIGHT AND MONDAY DEPICTED BY THE ECMWF IS BEING OVERLOOKED FOR NOW...AS THERE ARE DIFFERENCES IN THE MEDIUM RANGE MODELS. IT ALSO LOOKS LIKE THE SURFACE AND 850MB LOWS ARE TOO FAR SOUTH FOR SIGNIFICANT SNOW IN OUR FORECAST AREA...DESPITE THE QPF AMOUNTS PREDICTED BY THE ECMWF. SO WILL WAIT AND SEE AND KEEO DRY FORECAST FOR NOW. && .AVIATION...OCCASIONAL LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT RHI THROUGH THE EVENING. HEAVIEST BAND OF SNOW ENHANCED ALONG A SURFACE TROUGH AXIS...WHICH DROPPED VSBYS TO 1/4SM AT RHI EARLIER...HAS SHIFTED SOUTH OF THE TAF SITE. THIS BAND WILL WEAKEN AS IT BECOMES FARTHER REMOVED FROM LAKE SUPERIOR...BUT WILL HAVE POTENTIAL TO DROP VSBYS AT AUW/CWA TO IFR LEVELS MID TO LATE AFTERNOON. OTHERWISE...CENTRAL WI TAF SITES WILL SEE MVFR CIGS PREVAILING THROUGH EARLY EVENING WITH OCCASIONAL SNOW SHOWERS. LOW LEVEL MOISTURE SCOURS OUT OVERNIGHT AS HIGH PRESSURE MOVES INTO THE AREA...ENDING ANY LINGERING FLURRIES/SNOW SHOWERS AT THE TAF SITES. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ005. && $$ MPC/RDM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 1043 AM CST MON NOV 17 2008 .UPDATE...14Z SURFACE ANALYSIS AND LATEST RUC/VIS/IR/WV/RADAR IMAGERY SHOW A SHORTWAVE WITHIN FAST NW FLOW ALOFT NOW MOVING OVER THE ARROWHEAD OF MINNESOTA. THIS WAVE IS GIVING A SUBTLE TROUGH/CONVERGENCE AXIS A PUSH TO THE SOUTH OVER NORTHERN WISCONSIN AS EVIDENT BY A SOUTHWARD DRIFT IN A LAKE ENHANCED SNOW BAND OVER ONEIDA COUNTY. VSBYS WITHIN THIS SNOW BAND HAVE BEEN FALLING TO AROUND 3/4SM THIS MORNING...AND WOULDN`T BE SURPRISED TO HEAR A QUICK HALF INCH OF NEW SNOW WITH THE BAND`S PASSAGE. LOW LEVEL WINDS ARE SHIFTING MORE TOWARDS THE 350-360 DIRECTION BEHIND THE TROUGH...WHICH IS NOT NECESSARILY FAVORABLE FOR BEEFY ACCUMULATIONS. ADDITIONALLY...WONDER IF LOW LEVEL DRY AIR OVER ONTARIO AND THE ARROWHEAD OF MN WILL MAKE AN APPEARANCE THIS AFTERNOON AS SUBSIDENCE COMBINED WITH DAYTIME MIXING ERODE THE SNOW BANDS. SO DESPITE A 4 INCH SNOW REPORT RECEIVED EARLIER THIS MORNING FROM WINCHESTER...WILL NOT UPGRADE THE ADVISORY AT THIS TIME. OTHERWISE...HAVE REMOVED SNOW SHOWERS (KEPT SCT FLURRIES) FROM FAR NE WISCONSIN SINCE BELIEVE DOWNSLOPING WINDS AND MIXING WILL LIMIT INSTABILITY THIS AFTERNOON. MPC && .PREV DISCUSSION...ISSUED AT 424 AM CST MON NOV 17 2008... SHORT TERM...TODAY THROUGH TUESDAY... FOCUS OF FORECAST TODAY IS THE SHORT WAVE DROPPING SOUTH THROUGH THE STATE TODAY AND THE PROSPECT OF SEEING THE SUN ON TUESDAY. ANALYSIS AT 9Z SHOWING BROAD TROF OVER THE EASTERN HALF OF THE NATION WITH SHORT WAVE JUST NORTH OF THE MN BORDER. MAJOR EFFECTS OF THIS WAVE IS ITS ENHANCEMENT OF THE LAKE EFFECT BANDS OFF LAKE SUPERIOR. SHOWERS LAST EVENING LIMITED DUE TO DRY AIR MOVING OVER THE LAKE...THOUGH PAST HOUR VISIBILITIES DROPPING TO 1 MILE AT IWD AND 3 TO 4 MILES AT ARV. MODERATE INSTABILITY WITH LAKE INDUCED CAPES GREATER THAN 600 THROUGH THIS AFTERNOON. DIMINISHING TREND EXPECTED LATE THIS AFTERNOON AS SURFACE HIGH NOSES IN REDUCING INVERSION HEIGHTS AND DRY AIR ONCE MORE ADVECTS IN. STAYED WITH 2 TO 5 INCH RANGE...WITH HEAVIEST EXPECTED BETWEEN NOW AND NOON. ELSEWHERE HAVE STAYED WITH EVENING SHIFTS THOUGHTS OF ADDING SNOW SHOWERS TO TODAYS FORECAST FOR REMAINDER OF CWA. LLVL LAPSE RATES RATHER STEEP AHEAD OF WAVE AND ASSOCIATED SURFACE REFLECTION. AMOUNTS WILL BE LIGHT WITH NO SIGNIFICANT ACCUMULATION EXPECTED. THUS LOW POPS. SURFACE HIGH PRESSURE SHIFTS EAST ACROSS THE STATE TONIGHT AND TUE WITH CLOUDS DECREASING FOR SHORT TIME BEFORE MID/HIGH CLOUDS RETURN AHEAD OF NEXT SYSTEMLATE IN DAY TUE. LONG TERM...TUESDAY NIGHT THROUGH SUNDAY. THE HPC PREFERRED ECMWF SHOWED FLOW ALOFT GENERALLY FROM THE NORTHWEST THROUGH THE END OF THE WORK WEEK. A SHORT WAVE WAS EXPECTED TO REACH WISCONSIN BY 00Z THURSDAY AS A SURFACE LOW TRAVELS FROM SOUTHERN MINNESOTA TO UPPER MICHIGAN. HAVE GONE WITH CHANCE POPS IN THE NORTHERN PART OF THE FORECAST AREA WHERE THE SHORT WAVE ENERGY IS STRONGEST...THEN SLIGHT CHANCE A LITTLE FARTHER TO THE SOUTH...AND DRY ACROSS THE REST OF THE AREA. STRONG COLD ADVECTION IS FORECAST BEHIND THIS SYSTEM. 850MB TEMPERATURES WERE FORECAST TO FALL INTO THE -10C TO -17C RANGE OVER WESTERN LAKE SUPERIOR FROM 00Z THURSDAY THROUGH 00Z SATURDAY. WATER TEMPERATURES THERE AROUND 5C TO 7C SO LAPSE RATES WILL BE RATHER STEEP AND CHANCE POPS HAVE BEEN KEPT FOR AREAS IN THE LAKE SUPERIOR SNOWBELT. WINDS THEN BACK ENOUGH BY 00Z SATURDAY TO KEEP LAKE EFFECT AWAY AS STRONG WARM ADVECTION BEGINS OVER LAKE SUPERIOR. HIGH AND LOW TEMPERATURES ARE A MIX OF GUIDANCE AND HPC FORECAST. AVIATION...VFR CIGS EXPECTED FROM AUW TO GRB...WITH VISBYS DROPPING AT TIMES INTO MVFR RANGE TODAY IN SHSN AS TROF MOVES THROUGH REGION. LAKE EFFECT SHOWERS TO REDUCE CIGS/VISBYS INTO MVFR RANGE FOR MUCH OF DAY OVER FAR NORTH...LOCAL IFR CONDITIONS EXPECTED THROUGH EARLY AFTERNOON. IMPROVING CONDITIONS THIS EVENING UNDER HIGH PRESSURE. && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST THIS AFTERNOON FOR WIZ005. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 330 PM CST SUN NOV 16 2008 .SHORT TERM...TONIGHT AND MONDAY...LATEST RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW PERSISTENT UPPER TROUGHING OVER EASTERN NORTH AMERICA...WITH A SHORTWAVE ROUNDING THE BASE OF THE TROUGH OVER SOUTHERN LOWER MICHIGAN. ASSOCIATED SURFACE LOW IS GETTING LEFT BEHIND AS IT MOVES SOUTHEAST OVER NORTHERN IL...ALONG WITH ITS FGEN BAND. THAT LEAVES NORTHERN WISCONSIN WITHIN BROAD TROUGHING AT THE SURFACE AND UNDER A WIDESPREAD STRATO-CU FIELD. SCT FLURRIES HAVE BEEN NOTED BY SURFACE OBS AND RADAR...MOST COMMON OVER THE NORTHERN HALF OF THE FORECAST AREA. LOW LEVEL NW FLOW CONTINUES OVER LAKE SUPERIOR WITH ORGANIZED BANDS OVER CENTRAL AND EASTERN UPPER MICHIGAN...BUT STILL RATHER UNORGANIZED OVER THE WESTERN PART OF THE LAKE AS A RESULT OF REALLY DRY LOW LEVEL AIR (DEWPOINTS NORTH OF LAKE SUPERIOR AROUND 10F). THIS IS EXPECTED TO CHANGE LATE TONIGHT INTO TOMORROW MORNING WHEN ANOTHER SHORTWAVE AND A SHOT OF COLD AIR DROPS SE ACROSS THE WESTERN GREAT LAKES. THEREFORE...LAKE EFFECT SNOW ACCUMULATIONS ARE THE MAIN FORECAST CONCERN THROUGH TOMORROW. NORTHWEST FLOW LAKE EFFECT WILL CONTINUE DURING THE EVENING... BUT CONDITIONS DO NOT REALLY CHANGE THAT MUCH OVER WESTERN LAKE SUPERIOR. LOW LEVEL WINDS DO VEER TO A MORE FAVORABLE 340 DIRECTION...BUT OVER-LAKE INSTABILITY AND BL MOISTURE STAY RELATIVELY STEADY. CONDITIONS IMPROVE LATE OVERNIGHT INTO TOMORROW MORNING WHEN A SHORTWAVE DROPS SOUTH OUT OF MANITOBA SENDING A MODEST POCKET OF MID-LEVEL FORCING OVER THE LAKE. IN ADDITION...MODELS ALSO HINT AT A LOW LEVEL TROUGH ACCOMPANYING THIS WAVE...WHICH WILL BOOST LOW LEVEL CONVERGENCE AND ERODE SOME OF THIS LOW LEVEL DRY AIR. COLD ADVECTION ALSO IMPROVES...INCREASING OVER-LAKE INSTABILITY TO THE LOW 20S AND LAKE INDUCED CAPE TO AROUND 600 J/KG ACCORDING TO NAM BUFKIT. THIS SUPPORT DIMINISHES BY TOMORROW AFTERNOON WHEN LOW LEVEL WINDS VEER TO NEARLY DUE NORTH AND BECOME MORE ANTICYCLONIC. LOW LEVEL DRY AIR WILL ALSO RETURN AND THEREFORE...PLENTY OF SIGNALS TO INDICATE AN EROSION OF LES PM TOMORROW. ADDING IT ALL UP...BELIEVE AN ADVISORY IS STILL WARRANTED WITH 24 HOUR ACCUMULATIONS FROM 00Z MON TO 00Z TUE OF 2 TO 5 INCHES...AND AN ISOLATED 6 INCH AMOUNT NOT OUT OF THE QUESTION OVER NORTHERN VILAS COUNTY. NOT NEARLY AS MUCH TO TALK ABOUT OUTSIDE THE SNOW BELT. LINGERING LOW LEVEL MOISTURE AND CYCLONIC FLOW WILL CONTRIBUTE TO SCT FLURRIES TONIGHT. INCOMING SHORTWAVE AND SURFACE TROUGH DOES IMPROVE FORCING AND MOISTURE SOMEWHAT...BUT MODELS STILL INDICATE AMPLE LOW LEVEL DRY AIR WITH AN INVERTED V SOUNDING WHICH WILL LIMIT DIURNAL INSTABILITY. AS A RESULT...THINK THIS IS MORE OF A WIDESPREAD FLURRIES EVENT...AND THAT ANY ACCUMULATIONS WILL BE HARD TO COME BY. LOWS TONIGHT NEAR 20 NORTH TO THE MIDDLE 20S SE. HIGHS TOMORROW RANGING FROM THE MIDDLE 20S NORTH TO MIDDLE 30S SE. .LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. NORTHWEST UPPER FLOW WILL KEEP COLDER THAN NORMAL AIR IN THE REGION THROUGH THE MUCH OF THE WEEK. THEN THE FLOW BECOMES MORE ZONAL AND MODEL DIFFERENCES ARE VERY APPARENT BY THE END OF THE WEEK. THE GFS ENSEMBLE MEMBERS ARE ALL OVER THE PLACE STARTING THURSDAY NIGHT AND FRIDAY. THE ECMWF IS MUCH FLATTER THAN THE GFS AND SEEMS TO BE PREFERRED BY NCEP FORECASTERS. GIVEN THE LARGE DIFFERENCES IN THE MODELS DECIDED TO KEEP MUCH OF WHAT WE HAVE BEEN FORECASTING WHICH IS CLOSE WHAT WHAT NCEP HAS. A WEAK SHORTWAVE MOVES THROUGH WEDNESDAY...WHICH COULD PRODUCE SOME LIGHT SNOW OR FLURRIES IN THE NORTH. THEN LAKE EFFECT SNOWS BEGIN AGAIN IN THE NORTHCENTRAL PART OF THE STATE WEDNESDAY NIGHT THROUGH THURSDAY. && .AVIATION...BAND OF LIGHT SNOW OVER SW WISCONSIN WILL SLIDE SE THIS AFTERNOON AND MISS THE TAF SITES. BUT CIGS WILL BOUNCE AROUND BETWEEN MVFR AND VFR AT CWA/AUW FOR THE REST OF THE AFTERNOON AND POTENTIALLY INTO TONIGHT. AT RHI...BANDS OF LAKE EFFECT SNOW WILL BECOME MORE NUMEROUS LATE THIS AFTERNOON THROUGH TOMORROW WHEN A RENEWED SURGE OF COLD AIR AND NORTH TO NORTH WINDS MOVE IN. IFR CIGS/VSBYS WILL BE COMMON WITHIN THE HEAVIER LAKE EFFECT SNOW SHOWERS. AT GRB...VFR CIGS/VSBYS WILL BE PREVAILING. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL 6 PM CST MONDAY FOR WIZ005. && $$ MPC/RDM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 1026 AM CST SUN NOV 16 2008 .UPDATE...13Z SURFACE/RUC ANALYSIS...AND LATEST IR/WV/RADAR SHOW A SHORTWAVE PUSHING ACROSS SE WISCONSIN WITH ITS ASSOCIATED WEAK SURFACE LOW OVER THE MINNESOTA/IOWA BORDER. FRONTOGENETICAL LIGHT SNOW BAND...ON THE NE FLANK OF THE LOW LEVEL CIRCULATION...CONTINUES TO MOVE SE WITH THE SURFACE LOW AND IS JUST GRAZING THE FAR SW FORECAST AREA. ELSEWHERE...NW FLOW LAKE EFFECT CONTINUES TO SEND LIGHT SNOW SHOWERS TOWARDS FAR NORTHERN WI WHILE JUST WIDELY SCT FLURRIES RESIDE EVERYWHERE ELSE. FOR THE REST OF TODAY...THE WEAK SURFACE LOW AND FGEN BAND WILL SHIFT SE TOWARDS NORTHERN ILLINOIS...WHICH WILL KEEP ONLY LIGHT SNOW CONFINED TO WOOD AND MAYBE MARATHON AND PORTAGE COUNTIES. LAKE EFFECT SNOW SHOWERS WILL ALSO BECOME MORE PERSISTENT OVER VILAS COUNTIES AS LOW LEVEL WINDS VEER TO A MORE FAVORABLE POSITION DURING THE AFTERNOON. BETTER ACCUMULATIONS STILL LOOK GOOD FOR TONIGHT AND NO ADJUSTMENT IN THE HEADLINES ARE WARRANTED AT THIS TIME. WILL TAKE A CLOSER LOOK IN THE AFTERNOON FORECAST PACKAGE. BUT FOR THE MAJORITY OF NE WISCONSIN...HAVE BACKED OFF ON THE LIGHT SNOW SHOWER WORDING...REDUCING IT TO ONLY SCT FLURRIES. LASTLY...HAVE NUDGED HIGH TEMPS DOWN A COUPLE DEGREES. MPC && .PREV DISCUSSION...ISSUED AT 351 AM CST SUN NOV 16 2008... SHORT TERM...TODAY THROUGH MONDAY... NW FLOW REGIME CONTINUES OVER UPPER MIDWEST WITH RIDGE OVER THE WEST AND TROF OVER THE EASTERN SEABOARD. WATER VAPOR IMAGERY SHOWING SHORT WAVE DROPPING SOUTHEAST THROUGH DAKOTAS/WESTERN MN. ASSOC SFC LOW NR JAMESTOWN...DROPPING SOUTHEAST. BAND OF LIGHT SNOW FLURRIES BREAKING OUT ALONG LINE FROM MSP TO BJI IN AREA OF WAA ADVECTION/FRONTOGENETIC FORCING AHEAD OF SFC WAVE. MODELS CONSISTENT WEAKENING LOW AS IT PASSES TO THE SOUTHWEST OF STATE. WILL CONTINUE WITH PREVIOUS THOUGHTS FOR POPS TODAY...WITH BEST CHANCES OVER CENTRAL WI. SHORT WAVE TO USHER IN COLDER AIR WITH LLVL WINDS SHIFTING BACK TO THE NORTHWEST...BECOMING FAVORABLE ONCE AGAIN FOR LES OFF LAKE SUPERIOR. WILL ISSUE ADVISORY WITH THIS ISSUANCE. WILL RUN FROM 00Z MON TO 00Z TUE WITH THOUGHTS OF MOST SNOW FALLING BETWEEN THE 06Z TO 18Z PERIOD WHEN LAKE INDUCED INSTABILITY/LIFT INTERSECTS ZONE OF BEST SNOW GROWTH. LES MAY ALSO GET ADDED ENHANCEMENT FROM NEXT SHORTWAVE DROPPING SOUTH THROUGH STATE EARLY MON. SURFACE HIGH BEGINS TO BUILD IN LATER MON WITH DRIER AIR AND LOWERING INVERSION HEIGHTS. LES FLOW CHART SUGGESTS UP TO 6 INCHES FOR PERIOD. CLOUD COVER ONCE AGAIN HOLDING TEMPS UP...ABOVE GUIDANCE. HAVE TRENDED TOWARDS MAV GUIDANCE MODERATING IT SOMEWHAT. LONG TERM...MON NGT THRU NXT SAT. MAIN FCST FOCUS REMAINS ON TRYING TO TIME SNOW CHCS ACROSS THE FCST AREA AND POTENTIAL FOR ADDL LK EFFECT SNOWS FOR NRN WI AT MID-WEEK. INITIAL LK EFFECT CONDITIONS BEGIN TO TURN UNFAVORABLE MON NGT AS A LRG AREA OF HI PRES BUILDS TOWARD THE WRN GREAT LKS. AN INFLUX OF DRY AIR...COMBINED WITH WNDS STARTING TO BACK WL SHOVE THE LK EFFECT BANDS FARTHER TO THE EAST AND AWAY FROM N-CNTRL WI. NEED TO CARRY A HI CHC POP FOR VILAS CNTY THRU MON EVENING AND THEN TAPER SNOW DOWN TO MAINLY FLURRIES AFT MIDNGT. THE REST OF NE WI WL REMAIN DRY AND WITH SOME PARTIAL CLEARING OVRNGT...THIS SHOULD ALLOW FOR TEMPS TO DROP INTO THE TEENS FOR ALL BUT THE LKSHR AREAS. THE HI PRES MOVS ACROSS WI ON TUE AND WL PROVIDE FOR A DECENT AMT OF SUNSHINE THRU THE DAY. SOME LATE AFTERNOON HI CLDS MAY PUSH TOWARD CNTRL WI AS RETURN FLOW DVLPS AND WARMER AIR ALOFT MAKES A PUSH TOWARD THE WRN GREAT LKS. EVEN THE RETURN OF THE SUN WL NOT BRING MUCH WARMTH TO NE WI AS MAX TEMPS STRUGGLE TO GET INTO THE 30S. MDLS AGREE ON BRINGING A CLIPPER-TYPE SYSTEM TOWARD THE WRN GREAT LKS TUE NGT...BUT DIFFER ON BOTH SPD AND PLACEMENT OF THE SFC LOW. ON ONE HAND...YOU HAVE THE FASTER ECWMF/CANADIAN/UKMET WHICH BRING THE SFC LOW AND ITS ASSOCIATED CDFNT INTO THE WRN GREAT LKS BY 12Z WED. ON THE OTHER HAND...THE NAM IS MUCH SLOWER WITH THE SFC LOW STILL OVR MB AND THE CDFNT OVR THE PLAINS. THE GFS WAS MORE DIPLOMATIC WITH ITS SOLN IN BETWEEN THE OTHER MDLS. DUE TO MEAN FLOW TRYING TO DEAMPLIFY...FEEL THE FASTER SOLN IS CORRECT AND EXPECT THE CDFNT TO REACH CNTRL WI BY 12Z WED. THE RATHER STG WAA PRECEDING THE CDFNT OVR WI TUE NGT MAY BE ENUF TO KICK OFF SOME LGT SNOW ACROSS NE WI ALTHO BETTER CHCS SHOULD BE NORTH OF THE MI BORDER WHERE THE BETTER FORCING TO EXIST. PREV FCST HAD A PRETTY GOOD HANDLE ON THIS SITN...SO LITTLE CHG MADE. THE SFC LOW AND CDFNT TO COMPLETE THEIR PASSAGE THRU WI WED MORNING WITH A WND SHIFT TO THE NW AND CAA DEVELOPING ACROSS THE AREA BY WED AFTERNOON. WHILE A STRAY SNOW SHWR OR FLURRY IS PSBL WITH THE FROPA...PREFER TO FOCUS ON THE REDEVELOPMENT OF LK EFFECT SNOW SHWRS OVR NRN WI FOR WED AFTERNOON. 8H TEMPS DROP TO AROUND -13C BY 00Z THU OVR LK SUPERIOR AND AS TRAJS BECOME MORE FAVORABLE...EXPECT THE SNOW SHWR ACTIVITY TO STEADILY INCREASE. VILAS CNTY AGAIN WL BE SUSCEPTIBLE AND HAVE RAISED POPS TO HI CHC FOR NOW WITH MINOR ACCUMULATIONS PSBL. THE LK EFFECT SNOW SHWRS SHOULD THEN CONT TO IMPACT NRN WI RIGHT ON THRU THU AS WNDS REMAIN NW...DELTA-T VALUES RESIDE IN THE UPR TEENS/LWR 20S AND LK-INDUCED CAPES CLIMB TO > 400 J/KG. MUCH TOO EARLY TO DETERMINE ACCUMULATIONS...BUT EXPECT TO SEE AT LEAST A FEW INCHES TO FALL OVR THE FAVORED AREAS OF VILAS CNTY. DO ANTICIPATE THE LK EFFECT TO DIMINISH A BIT LTR ON THU AS HI PRES BEGINS TO ENCROACH ON THE RGN. THE REST OF NE WI WL STAY MOSTLY CLDY WED NGT...BUT SOME BREAKS IN THE CLDS SHOULD TAKE PLACE ON THU AS THE HI PRES APPROACHES. THE LK EFFECT SNOWS FOR NRN WI ARE PROGGED TO END THU NGT AS THE HI PRES PUSHES INTO WI AND TRAJS BECOME UNFAVORABLE. QUIET CONDITIONS FOR FRI WITH THE HI PRES IN CONTROL...YET TEMPS STILL A BIT COOL FOR LATE NOVEMBER. MDLS HAVE SOME MINOR TIMING DIFFERENCES WITH RESPECT TO THE NXT PAC SYSTEM. HOWEVER...THERE ARE ENUF SIMILIARITIES SUCH THAT CHC POPS MAY BECOME NECESSARY NXT SAT IF TRENDS PERSIST. && AVIATION...TYPICAL NOVEMBER CLOUDINESS CONTINUES...WITH MAINLY VFR CIGS/VISBYS EXPECTED...LOCALLY LOWERING IN SNOW SHOWERS TO IFR/MVFR LEVELS OVER CENTRAL TODAY AND NORTH CENTRAL TODAY AND TONIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST MONDAY FOR WIZ005. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1243 AM EST TUE NOV 18 2008 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT FOLLOWED BY COLD HIGH PRESSURE THAT WILL PERSIST THROUGH WEDNESDAY NIGHT. A DRY REINFORCING COLD FRONT WILL MOVE THROUGH THE AREA THURSDAY... FOLLOWED BY HIGH PRESSURE THROUGH THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE STRONG COLD FRONT IS BEGINNING TO MOVE INTO THE WESTERN ZONES AND WILL SWEEP THROUGH THE ENTIRE FORECAST AREA OVER THE 2 HOURS OR SO BEFORE PUSHING OFFSHORE. EXPECT WINDS TO INCREASE AND DEWPOINTS TO FALL AFTER FRONTAL PASSAGE WITH TEMPERATURES INITIATING A STEADY DECLINE WITH THE ONSET OF STRONG COLD AIR ADVECTION. OVERNIGHT LOWS LOOK ON TRACK ALTHOUGH WILL NEED TO LOWER THEM 1-2 DEGS AROUND THE METTER...REIDSVILLE AND LUDOWICI AREAS BASED ON OBSERVATIONAL AND MODEL TRENDS. LOCATIONS WELL INLAND WILL DROP INTO THE LOWER TO MID 30S PRIOR TO SUNRISE...BUT LOCAL FROST TOOLS INDICATE NO CHANCES FOR FROST GIVEN THE DRYING SURFACE LAYER AND INCREASING WIND FIELDS. IN ALL VERY FEW CHANGES ARE NEEDED THIS EVENING. LAKE WINDS...WINDS ARE BEGINNING TO INCREASE ON LAKE MOULTRIE THIS EVENING AS THE COLD FRONT APPROACHES. WINDS WILL SURGE HARD BY MIDNIGHT THE ONSET OF STRONG COLD AIR ADVECTION. 850MB TEMPERATURES AROUND -5C COUPLED WITH LAKE TEMPERATURES IN THE LOWER 60S WILL YIELD VERY FAVORABLE MIXING PROFILES...WHICH SHOULD HELP SURGE WINDS SOLIDLY INTO THE 20-25 KT RANGE. THE LAKE WIND ADVISORY WILL CONTINUE. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... DESPITE SUNNY SKIES...STRONG COLD ADVECTION...FEATURING A DEEPENING THERMAL TROUGH WITH 850 MB TEMPERATURES FALLING INTO THE -5C TO -9C RANGE...TEMPERATURES WILL STRUGGLE TO CLIMB OUT OF THE 40S AT MANY LOCATIONS TUESDAY. RECORD LOW MAXIMUM HIGH TEMPERATURES FOR NOVEMBER 18 WILL BE CHALLENGED...ESPECIALLY AT THE CHARLESTON AIRPORT. TUESDAY NIGHT...CONDITIONS APPEAR FAVORABLE FOR SEVERAL HOURS OF WIDESPREAD FREEZING TEMPERATURES...AND PERSISTENT OFFSHORE WINDS MAY PUSH FREEZING CONDITIONS TO THE COAST. THUS...ISSUED A FREEZE WATCH FOR ALL AREAS...EXCEPTING ALLENDALE...SCREVEN AND JENKINS COUNTIES WHERE THE GROWING SEASON HAS ENDED DUE TO AN EARLIER FREEZING EVENT. EXPECT LOWS TO RANGE FROM THE LOWER TO MID 20S ACROSS MANY AREAS AWAY FROM THE IMMEDIATE COAST...TO THE LOWER 30S ALONG THE COAST. RECORD LOW TEMPERATURES FOR NOVEMBER 19 WILL BE CHALLENGED. DESPITE THE VERY COLD TEMPERATURES...PERSISTENT N/NW WINDS SHOULD GREATLY LIMIT/PREVENT FROST FORMATION. LAKE WIND...OVER-LAKE INSTABILITY WILL CONTRIBUTE TO GUSTY WINDS...AS HIGH AS 30 KNOTS AT TIMES...OVER LAKE MOULTRIE TUESDAY AND TUESDAY NIGHT. PER 12Z MODEL TRENDS DEPICTING A SIGNIFICANT RELAXATION OF LOW LEVEL WINDS BY WEDNESDAY MORNING...ADJUSTED THE END TIME FOR THE LAKE WIND ADVISORY FROM NOON TO 6 AM WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... MOSTLY CLEAR AND COOL CONDITIONS WILL PREVAIL WED THROUGH SAT... DESPITE THE PASSAGE OF A DRY COLD FRONT ON THU. HIGH PRES WILL GRADUALLY SHIFT OFFSHORE WED NIGHT...BRINGING AN END TO THE STRONG CAA THAT WILL HAVE BROUGHT MAX TEMPS TO ONLY THE LOW-MID 50S WED FOLLOWED BY MIN TEMPS IN THE UPPER 20S TO LOWER 30S WED NIGHT. SOME MODEST WARM AIR ADVECTION WILL OCCUR THU AHEAD OF A COLD FROPA DUE FOR LATE DAY THU TO POSSIBLY THU EVE. ALTHOUGH THERE WILL BE SOME INCREASE IN CLOUD COVER...MAX TEMPS WILL REACH THE LOW-MID 60S WHICH IS STILL SOME 3-6 DEGREES BELOW NORMAL. DESPITE THE MODEST INCREASE IN THE MOISTURE COLUMN...NO PRECIP IS EXPECTED. ANOTHER SHOT OF CAA IS EXPECTED THU NIGHT THROUGH FRI NIGHT BEHIND THE CDFNT WITH AN E COAST TROUGH AND WESTERN RIDGE DEVELOPING...ALLOWING ANOTHER CANADIAN HIGH PRES AIRMASS TO SLIDE INTO THE ERN CONUS. MIN TEMPS WILL AGAIN DROP TO THE 30S WITH MAX TEMPS IN THE UPPER 50S TO LOWER 60S...BUT THE CAVEAT IS THAT THESE TEMPS COULD BE ON THE HIGH SIDE IF CAA IS STRONGER THAN ANTICIPATED. TEMPS MODERATE OVER THE WEEKEND CLOSER TO NORMAL LEVELS...BUT THE POSSIBILITY IS THERE THAT ANOTHER COLD FRONT MAY PUSH THROUGH ON MONDAY AND GIVE ANOTHER SHOT OF COLDER AIR. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD AT BOTH SITES. THE MAIN ISSUE WILL BE GUSTY NNW WINDS WITH STRONG CANADIAN HIGH PRESSURE BUILDING IN WITH VERY COLD AIR ASSOCIATED WITH IT. WINDS WILL BEGIN TO GUST TO AROUND 20 KT EARLY THIS MORNING WITH SPEEDS INCREASING DURING THE DAY TODAY. WINDS WILL PROBABLY NOT DIE OFF TONIGHT ALTHOUGH SPEEDS AND GUSTS WILL BE AT OR BELOW 10 KT. EXTENDED AVIATION OUTLOOK...VFR. && .MARINE... WINDS WILL SURGE ACROSS THE WATERS TONIGHT IN THE WAKE OF STRONG COLD FRONT AND SMALL CRAFT ADVISORIES FOR THE NEARSHORE WATERS INCLUDING CHARLESTON HARBOR LOOK GOOD. SUSPECT THERE MAY BE 4-5 HOUR PERIOD OF GALES ACROSS THE GEORGIA OFFSHORE WATERS WHERE HIGH RESOLUTION SST DATA SHOWS WATER TEMPERATURES HOLDING IN THE UPPER 60S TO LOWER 70S BETWEEN 40 AND 60 NM OUT. RUC AND NAM ADJUSTED SOUNDINGS IN THIS AREA SUPPORT VIGOROUS MIXING PROFILES OVERNIGHT AS INTENSE COLD AIR ADVECTION INTERACTS WITH THESE WARMER WATERS. WILL ISSUE A GALE WARNING FOR THIS AREA THROUGH 5 AM...AFTER WHICH WINDS SHOULD SUBSIDE JUST BELOW GALE FORCE. A TIGHT SURFACE PRESSURE GRADIENT AND STRONG COLD ADVECTION/OVER WATER INSTABILITY WILL CONTRIBUTE TO A CONTINUATION OF WIDESPREAD SMALL CRAFT ADVISORY CONDITIONS TUESDAY AND TUESDAY NIGHT. AS CAA SHUTS DOWN BY WED MORNING...WIND SPEEDS WILL STEADILY DROP BELOW SCA LEVELS FOR ALL MARINE ZONES BY DAYBREAK WED. THE ONLY CONCERN IS SEAS...AND ATTM WAVE HEIGHTS ARE EXPECTED TO BE UNDER 6 FT FOR ALL NEARSHORE WATERS. HOWEVER...THE OUTER GA WATERS WILL BE SLOWER TO EXPERIENCE THE DROP UNDER THE SOLID OFFSHORE FLOW SO WILL MAINTAIN THE SCA HEADLINE THROUGH THE DAY ON WED. AS HIGH PRES MOVES ACRS THE WATERS WED INTO WED NIGHT...SEAS IN THE OUTER GA WATERS WILL DROP BELOW 6 FT. ANOTHER COLD FRONT IS EXPECTED FOR LATE THU INTO THU NIGHT AND ANOTHER SHOT OF CAA ALONG WITH IT THAT WILL INCREASE CONDITIONS OVER THE WATERS. ATTM...THE STRENGTH OF THE CAA DOES NOT APPEAR TO BE REACH THAT OF THE CAA EXPECTED FOR TUE SO HAVE KEPT SEAS NO HIGHER THAN 5 FT AND WIND SPEEDS NO HIGHER THAN 20 KT. SHOULD THE MODELS AND TRENDS DICTATE OTHERWISE...THEN SCA HEADLINES MAY BE NEEDED LATER THIS WEEK. HIGH PRES THEN RETURNS FOR FRI THROUGH THE WEEKEND...MAKING FOR TRANQUIL CONDS BY THEN. && .FIRE WEATHER... FIRE WEATHER CONCERNS ARISE BOTH TUE AND WED WITH THE DRY AIRMASS SETTLING OVER THE AREA ALONG WITH THE COLD AIR ADVECTION. FOR TUE...RH VALUES DROP TO AROUND THE CRITICAL LEVEL OF 25 PERCENT...RANGING FROM 24-27 PERCENT AWAY FROM THE COAST AND IN THE UPPER 20S CLOSER TO THE COAST. ADDED TO THAT WILL BE WIND SPEEDS NEAR TO AROUND CRITICAL LEVELS TUE AFTERNOON. HOWEVER...AFTER CONSULTING USERS IN BOTH SC AND GA...FUEL MOISTURES AT BOTH THE 10 AND 100 HOUR TIME RANGES ARE RUNNING MOIST ENOUGH FROM THE WEEKEND RAINS THAT NO ADDITIONAL FIRE WX STATEMENTS ARE NEEDED. FOR WED... WIND SPEEDS WILL BE LOWER BUT RH LEVELS WILL BE DRIER...POSSIBLY DROPPING BELOW 20 PERCENT. SINCE ONLY THE RH CRITERIA WILL BE REACHED ON WED...NO ADDITIONAL FIRE WX PRODUCTS WILL BE NEEDED. FOR BOTH TUE AND WED...WILL RUN WITH THE APPROPRIATE HEADLINES IN THE FIRE WEATHER PLANNING FORECAST. && .CLIMATE... RECORD LOW MAXIMUM TEMPERATURES FOR TUESDAY... CHS...49/1951 CHL...48/1951 SAV...45/1891 RECORD LOWS FOR WEDNESDAY... CHS...27/1949 CHL...32/1951 SAV...27/1951 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FREEZE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR GAZ099>101-114>119-137>141. SC...FREEZE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR SCZ042>045-047>051. LAKE WIND ADVISORY UNTIL 6 AM EST WEDNESDAY FOR SCZ045. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR AMZ330-350- 352-354. GALE WARNING UNTIL 5 AM EST EARLY THIS MORNING FOR AMZ374. && $$ JRL ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 321 AM CST TUE NOV 18 2008 .DISCUSSION... 215 AM CST INTENSE LAKE EFFECT SNOW BAND HAS BACKED UP INTO PORTER AND EASTERN LAKE COUNTIES OF NORTHWEST INDIANA. NAM12 AND RUC13 MODEL OUTPUT SEEM TO HAVE A REASONABLE HANDLE ON THIS. VERY COLD MID LEVEL AIR FOLLOWING SHORT WAVE TROUGH THAT DROPPED SOUTHEAST ACROSS THE REGION LAST EVENING HAS ALLOWED CLOUD TOPS OF LAKE EFFECT BAND APPROACH 20K FT IN DEPTH. EXPECT MODERATE TO HEAVY LAKE EFFECT IN FAR NORTHWEST INDIANA WITH LIGHTER SNOW SHOWERS AS FAR WAST AS THE ILLINOIS STATE LINE. UPGRADED PORTER TO A LAKE EFFECT SNOW WARNING AND INTRODUCED FOR LAKE COUNTY WHERE INTENSE SNOWFALL EXPECTED UNDER THE CORE OF THE SNOW BAND DURING THE PREDAWN THROUGH MID MORNING BEFORE THE BAND SHIFTS BACK EASTWARD AND WARMING IN THE MID LEVELS DECREASES THE DEPTH OF THE LAKE EFFECT AND THUS ITS INTENSITY. A LAKE EFFECT SNOW ADVISORY HAS ALSO BEEN ISSUED FOR NEWTON AND JASPER WHERE SOME HEAVIER SNOW IS LIKELY TO STRETCH SOUTH OF THE KANKAKEE RIVER. TRS && .AVIATION... 1050 PM CDT 0600 UTC TAFS...SKIES HAVE RAPIDLY CLEARED OUT ACROSS THE REGION AS THE UPPER LEVEL SUPPORT THAT LED TO THE SNOW SHOWERS EARLIER THIS EVENING HAS MOVED OFF TO THE EAST ACROSS THE GREAT LAKES. THIS TREND SHOULD CONTINUE OVERNIGHT INTO TUESDAY AS THE SFC RIDGE MOVES INTO THE REGION. THE ORD/MDW SITES WILL LIKELY BE PICKING UP ON THE LOW CLOUDS OVER THE LAKE THROUGH TUESDAY MORNING...OTHERWISE SKIES WILL MAINLY BE CLEAR UNTIL THE UPPER LEVEL JET USHERS IN SOME CIRRUS INTO THE MIDWEST BY AFTERNOON TUESDAY. WINDS WILL CONTINUALLY DIMINISH OVERNIGHT AS THE SFC RIDGE SWINGS SOUTH OF THE REGION. WINDS WILL COME BACK AROUND TO THE SOUTH ON TUESDAY NIGHT AS THE RIDGE AXIS PASSES AND A LOW PRESSURE SYSTEM TRACKS INTO NORTHERN MINNESOTA. EXPECT VFR CONDITIONS THROUGHOUT THE FORECAST PERIOD. HALBACH && .MARINE... 314 AM CST A LARGE HIGH WAS OVER MINNESOTA AND IOWA THIS MORNING. A WEAK LOW WAS OVER SOUTHWEST MICHIGAN. THIS LOW IS PART OF THE LAKE EFFECT SNOW OVER NORTHWEST INDIANA AND SOUTHWEST MICHIGAN. ANOTHER LOW WAS AT 38 NORTH LATITUDE AND 74 WEST LONGITUDE. THIS LOW...OFF THE COAST OF NEW JERSEY...AND THE HIGH ARE PROVIDING THE NORTH WIND ON LAKE MICHIGAN THIS MORNING. THE HIGH WILL MOVE SOUTHEAST TO WESTERN KENTUCKY BY THIS EVENING. A LOW WILL DEVELOP IN NORTH DAKOTA AND WILL MOVE TO EASTERN LAKE SUPERIOR BY WEDNESDAY AFTERNOON. BY THURSDAY EVENING...A LARGE HIGH WILL MOVE TO CENTRAL MANITOBA AND SPREAD SOUTH TO OKLAHOMA. WE EXPECT NO FREEZING SPRAY THIS MORNING OR TUESDAY NIGHT. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...LAKE EFFECT SNOW WARNING...INZ001-INZ002 UNTIL NOON TUESDAY. LAKE EFFECT SNOW ADVISORY...INZ010-INZ011 UNTIL NOON TUESDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 219 AM CST TUE NOV 18 2008 .DISCUSSION...UPDATE FOR LAKE EFFECT 215 AM CST INTENSE LAKE EFFECT SNOW BAND HAS BACKED UP INTO PORTER AND EASTERN LAKE COUNTIES OF NORTHWEST INDIANA. NAM12 AND RUC13 MODEL OUTPUT SEEM TO HAVE A REASONABLE HANDLE ON THIS. VERY COLD MID LEVEL AIR FOLLOWING SHORT WAVE TROUGH THAT DROPPED SOUTHEAST ACROSS THE REGION LAST EVENING HAS ALLOWED CLOUD TOPS OF LAKE EFFECT BAND APPROACH 20K FT IN DEPTH. EXPECT MODERATE TO HEAVY LAKE EFFECT IN FAR NORTHWEST INDIANA WITH LIGHTER SNOW SHOWERS AS FAR WAST AS THE ILLINOIS STATE LINE. UPGRADED PORTER TO A LAKE EFFECT SNOW WARNING AND INTRODUCED FOR LAKE COUNTY WHERE INTENSE SNOWFALL EXPECTED UNDER THE CORE OF THE SNOW BAND DURING THE PREDAWN THROUGH MID MORNING BEFORE THE BAND SHIFTS BACK EASTWARD AND WARMING IN THE MID LEVELS DECREASES THE DEPTH OF THE LAKE EFFECT AND THUS ITS INTENSITY. A LAKE EFFECT SNOW ADVISORY HAS ALSO BEEN ISSUED FOR NEWTON AND JASPER WHERE SOME HEAVIER SNOW IS LIKELY TO STRETCH SOUTH OF THE KANKAKEE RIVER. TRS && .AVIATION... 1050 PM CDT 0600 UTC TAFS...SKIES HAVE RAPIDLY CLEARED OUT ACROSS THE REGION AS THE UPPER LEVEL SUPPORT THAT LED TO THE SNOW SHOWERS EARLIER THIS EVENING HAS MOVED OFF TO THE EAST ACROSS THE GREAT LAKES. THIS TREND SHOULD CONTINUE OVERNIGHT INTO TUESDAY AS THE SFC RIDGE MOVES INTO THE REGION. THE ORD/MDW SITES WILL LIKELY BE PICKING UP ON THE LOW CLOUDS OVER THE LAKE THROUGH TUESDAY MORNING...OTHERWISE SKIES WILL MAINLY BE CLEAR UNTIL THE UPPER LEVEL JET USHERS IN SOME CIRRUS INTO THE MIDWEST BY AFTERNOON TUESDAY. WINDS WILL CONTINUALLY DIMINISH OVERNIGHT AS THE SFC RIDGE SWINGS SOUTH OF THE REGION. WINDS WILL COME BACK AROUND TO THE SOUTH ON TUESDAY NIGHT AS THE RIDGE AXIS PASSES AND A LOW PRESSURE SYSTEM TRACKS INTO NORTHERN MINNESOTA. EXPECT VFR CONDITIONS THROUGHOUT THE FORECAST PERIOD. HALBACH && .MARINE... 410 PM CST A TROUGH OF LOW PRESSURE EXTENDS FROM DEEP LOW PRESSURE OVER BAFFIN BAY THROUGH THE EASTERN GREAT LAKES. A LARGE...SPRAWLING AREA OF HIGH PRESSURE OVER THE DAKOTAS IS BUILDING SOUTH AND EAST...AND WILL BE CENTERED OVER IOWA TONIGHT. AS THIS LARGE HIGH PRESSURE AREA SPREADS EAST OVER THE OHIO VALLEY TUESDAY NIGHT...WINDS WILL TEMPORARILY WEAKEN OVER LAKE MICHIGAN TUESDAY AND TUESDAY EVENING. ANOTHER LOW IS EXPECTED TO TRACK THROUGH THE NORTHERN PLAINS WEDNESDAY AND THE UPPER GREAT LAKES WEDNESDAY NIGHT. A COLD FRONT ASSOCIATED WITH THIS LOW WILL SWEEP ACROSS THE LAKE WEDNESDAY NIGHT...TURNING WINDS NORTHWESTERLY AGAIN AND INCREASING TO NEAR GALE FORCE LEVELS. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...LAKE EFFECT SNOW WARNING...INZ001-INZ002 UNTIL NOON TUESDAY. LAKE EFFECT SNOW ADVISORY...INZ010-INZ011 UNTIL NOON TUESDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA && $$ il AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 1216 AM EST TUE NOV 18 2008 UPDATED AVIATION DISCUSSION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 1000 PM EST SUBSIDENCE IN THE WAKE OF SHORTWAVE MOVING THRU LWR MI AND SFC HIGH PRES BUILDING E FROM WRN MN WILL SPELL A WEAKENING TREND IN LES OVERNIGHT. 00Z CWPL/KINL SOUNDINGS SHOW EXPECTED LOWERING INVERSIONS NICELY WITH KINL SOUNDING REPRESENTING A MORE HOSTILE ENVIRONMENT FOR LES WITH LOWER INVERSION AROUND 865MB/4.4KFT MSL AND A WELL MIXED BOUNDARY LAYER. RADAR NEAR THUNDER BAY ONTARIO HAS ALSO SHOWN A RAPID DIMINISHING OF LES OFF LAKE NIPIGON THIS EVENING. SO...GOING FCST OF ENDING ADVY FAR W OVERNIGHT LOOKS ON TRACK. OVER THE W... LOCALIZED CONVERGENCE BTWN ONTONAGON (NW WIND) AND UPPER ENTRANCE OF PORTAGE CANAL (NE WIND) HAS BEEN FOCUSING HEAVIER SNOW THIS EVENING IN FAR NRN ONTONAGON COUNTY TO THE NE OF ONTONAGON...AROUND THE HOUGHTON COUNTY LINE. THAT MAY CONTINUE FOR A FEW MORE HRS. TO THE E...ALTHOUGH OVERALL ENVIRONMENT WILL BECOME LESS FAVORABLE FOR LES...LAND BREEZES SHOULD DEVELOP STRONGER TONIGHT UNDER DECREASING SYNOPTIC WIND REGIME AND COOLER INTERIOR. LOCAL HIGH RES WRF-ARW AND ESPECIALLY THE 00Z RUC SHOW LOW-LEVEL CONVERGENCE STRENGTHENING THRU THE NIGHT INTO NCNTRL UPPER MI...BECOMING MORE TIGHTLY FOCUSED BTWN MARQUETTE AND DEERTON BY LATE IN THE NIGHT. THIS WILL WORK TO OFFSET THE NEGATIVE FACTORS LOCALLY. DOMINANT BAND IN THAT AREA WILL ALSO BENEFIT FROM PRECONDITIONING OFF LAKE NIPIGON. GOING FCST HAS THIS COVERED WELL...SO NO HEADLINE CHANGES ARE WARRANTED FOR THE CNTRL PORTION OF THE FCST AREA. FARTHER E...IT APPEARS SOME DECENT SNOW IS FALLING IN PORTIONS OF LUCE COUNTY THOUGH PERSISTENT BANDING IS NOT EVIDENT. SINCE LAND BREEZE OFF ONTARIO SHOULD VEER WINDS A BIT MORE NE OVER THE FAR ERN PART OF LAKE SUPERIOR...-SHSN SHOULD TEND TO DIMINISH WITH BULK OF HEAVIER SHSN SHIFTING W OF LUCE COUNTY DURING THE NIGHT. && .SYNOPSIS... ISSUED AT 432 PM EST 20Z WATER VAPOR LOOP AND RUC ANALYSIS SHOWED A POSITIVE PNA PATTERN WITH STRONG RIDGING ACROSS THE WESTERN U.S. INTO SW CANADA AND TROUGHING ACROSS EASTERN CANADA INTO THE GREAT LAKES. BETWEEN THE TROUGH AND RIDGE...A 120-140 KT JET AROUND 200MB EXTENDS FROM NORTHERN SASKATCHEWAN INTO SW MN. WITHIN THE UPPER TROUGH...THE MOST IMPORTANT FEATURE IN THE SHORT TERM IS A SHRTWV CROSSING NE WI. 12Z INL SOUNDING...WHICH WAS SITUATED SOMEWHAT CLOSE TO THE SHRTWV BACK AT 12Z...SHOWED A NEARLY SATURATED PROFILE FROM THE SFC TO 600MB... ALONG WITH TEMPS MOSTLY BELOW -10C THROUGH THIS LAYER. THIS COLD AIR CROSSING LAKE SUPERIOR CONTINUES TO GENERATE LAKE EFFECT SNOW SHOWERS...ESPECIALLY GIVEN THAT LAKE SURFACE TEMPERATURES ARE RUNNING 5-6C. BANDS WERE ORGANIZED THIS MORNING...PARTICULARLY OVER ERN MARQUETTE AND WRN ALGER COUNTIES WHERE OVER THE HIGHER TERRAIN SNOWFALL RATES WERE 1-1.5 INCHES PER HOUR. LOCATIONS NEAR THE SHORELINE WERE RUNNING A LITTLE LESS THAN THAT...DUE TO PROXIMITY OF THE WARMER LAKE PRODUCING MORE SMALLER SNOWFLAKES COMPARED TO THE DENDRITES OVER THE HIGHER TERRAIN. HOWEVER...DAYTIME HEATING DISRUPTED THE BANDS FOR EARLY THIS AFTERNOON. NOW THAT THE SUN IS SETTING...VISIBLE SATELLITE IMAGERY IS STARTING TO INDICATE A SINGLE BAND FORMING FROM LAKE NIPIGON...THROUGH CENTRAL LAKE SUPERIOR...TO MARQUETTE AND INTO NW LOWER MI. THIS IS DUE TO A NNE FLOW ON EASTERN LAKE SUPERIOR IMPINGING ON NW FLOW ACROSS THE WESTERN HALF OF THE CWA. TO THE WEST...1037MB HIGH PRESSURE CAN BE SEEN OVER THE PLAINS. DRIER AIR FROM THIS HIGH IS GRADUALLY MAKING IN ROADS INTO THE WESTERN CWA...NOTED BY DEWPOINTS AROUND 10F AT CMX AND IWD. THIS DRIER AIR HAS KEPT THE LAKE EFFECT FROM BEING AS HEAVY OVER WESTERN UPPER MI. LAST ITEM TO NOTE IS A SHRTWV COMING INTO THE NW BRITISH COLUMBIA COAST...WHICH IS THE NEXT SYSTEM TO AFFECT THE CWA. SNOWFALL AMOUNT WISE...LOCATIONS OVER THE HIGHER TERRAIN OF WESTERN ALGER COUNTY HAVE ALREADY SEEN OVER A FOOT SINCE LAST EVENING...WITH A REPORT FROM TRENARY AROUND 19 INCHES. MORE REPORTS CAN BE SEEN ON THE LATEST ARBLSRMQT. && .SHORT TERM (TONIGHT AND TUESDAY)... ISSUED AT 432 PM EST AS THE NW BRITISH COLUMBIA SHRTWV MOVES EAST OVER THE NEXT 24 HOURS...IT WILL PUSH THE SW CANADA RIDGE TOWARDS THE GREAT LAKES...MORE FLATTENING IT OUT WITH TIME. THIS MEANS MUCH OF THE WARM AIR ASSOCIATED WITH THE RIDGE IS EXPECTED TO STAY AWAY FROM HERE. HOWEVER...THE PROGRESSION OF THE RIDGE WILL ALLOW THE AREA OF HIGH PRESSURE OVER THE PLAINS TO CROSS UPPER MICHIGAN DURING THE DAY TUESDAY...ALLOWING LAKE EFFECT TO END WEST TO EAST. UNTIL THEN... TONIGHT APPEARS NOW OF MOSTLY MULTI-PARALLEL BANDS COMING OFF LAKE SUPERIOR...DUE TO SUBSIDENCE IN THE WAKE OF THE NE WI SHRTWV AND MOSTLY UNIDIRECTIONAL NORTH FLOW. IT IS POSSIBLE THAT SOME OF THE BANDS COULD BECOME STATIONARY...WHICH MEANS UPSLOPE AREAS SUCH AS IN MARQUETTE AND ALGER COUNTIES WITH THE LONGER FETCH OFF LAKE SUPERIOR COULD END UP WITH 5 INCHES OF 20-25 TO 1 SNOW. IN ADDITION...SINCE WE ARE GOING INTO THE DIURNAL MINIMUM WHEN LAND BREEZES ARE FAVORED...A STRONGER SINGLE BAND IS NOT OUT OF THE QUESTION. THEREFORE...AT LEAST THE WARNINGS FOR MQT..ALGER AND NRN SCHOOLCRAFT COUNTIES SEEM REASONABLE. FOR WESTERN UPPER MI...DRIER AIR SHOULD KEEP THE LAKE EFFECT TO A MINIMUM...THOUGH EXTRA CONVERGENCE IN THE GOGEBIC/ONTONAGON COUNTY AREA EXPECTED THIS EVENING MAY ALLOW FOR A LITTLE EXTRA SNOW AND THEREFORE EXTENDED THE ADVISORY. GOING LOW TEMPERATURES LOOKED REASONABLE. FOR TUESDAY...AGAIN LAKE EFFECT SNOW EXPECTED TO DIMINISH WEST TO EAST AS INVERSIONS LOWER...WINDS BACK AND DRIER AIR MOVES IN WITH THE HIGH PRESSURE AREA. IN FACT...MUCH OF THE WEST HALF OF THE CWA SHOULD BE DRY FOR THE AFTERNOON. WITH GRADUAL WARMING OF 850MB TEMPS...FROM AROUND -14C NOW TO -12C TUE AFTN...TOMORROW SHOULD END UP SLIGHTLY WARMER THAN TODAY. .LONG TERM (TUESDAY NIGHT THROUGH NEXT MONDAY)... SFC RDG AXIS WL BE OVER THE ERN U.P. AT 00Z TUE...BUT WAD CLD WL BE SPILLING IN FM THE W AHEAD OF NEXT SHRTWV SPILLING OVER THE RDG IN THE PLAINS. ALTHOUGH THE LLVLS WL BE INITIALLY DRY...THE ISENTROPIC LIFT SHOWN ON THE 280-295K SFCS/H85-5 QVECTOR CNVGC APPEARS SUFFICIENTLY STRONG TO GENERATE PCPN...ESPECIALLY OVER THE NE HALF OF THE FA WHERE PARCELS WL HAVE A LONGER PD OF UPGLIDE TO SATURATE AND WHERE FLOW OFF LK MI WL ACCENTUATE MOISTENING ACRS THE ERN ZNS. GFS MOS GUIDANCE SEEMS TO HAVE THE BEST HANDLE ON POPS. IN FACT... NAM/GFS QPF IS QUITE A BIT HIER OVER THE FAR ERN ZNS WHERE THERE IS LIKELY TO BE SOME LK ENHANCEMENT OF THE SHSN (H85 TEMPS FCST ARND -9C VS WATER TEMP ARND 8C) AFT 06Z IN SSW FLOW OVER THE LENGTH OF LK MI. NAM/GFS FCST SDNGS FOR ERY ALSO SHOW AN ALMOST 10K FT DEPTH OF LYR WITH TEMPS FVRBL FOR DENDRITIC SN GROWTH IN THE 06Z-12Z TIME FRAME. ELECTED TO BUMP UP POP TO HI CHC/LIKELY IN THIS AREA ABV MOS GUIDANCE. CLIPPER LO PROGGED TO SHIFT INTO ERN LK SUP BY 00Z THU. POTENTIAL FOR LK ENHANCED SHSN WL LINGER ON WED MRNG OVER THE FAR E...BUT VEERING FLOW TO W LATER IN THE DAY WL END THE THREAT. LATER SHIFTS MAY NEED TO CONSIDER AN ADVY FOR PORTIONS OF THE ERN ZNS BEFORE THE LK ENHANCED SN DIMINISHES THERE. WL INCLUDE MENTION IN HWO. OTRW... THREAT FOR LARGER SCALE PCPN WL END W-E WL LOSS OF ISENTROPIC LIFT AND MID LVL DRY SURGE UNDER UPR JET AXIS THAT WL CUT OFF LLVL MSTR FM DENDRITIC SN GROWTH LYR. OTRW...ARRIVAL OF CYC NW FLOW LATE IN THE DAY WL CAUSE SOME LES TO DVLP OVER THE W...BUT AIRMASS DOES NOT APPEAR SUFFICIENTLY COLD UNTIL LATE FOR SGNFT LES (H85 TEMP ARND -6C OVER WRN LK SUP AT 18Z FALLS TO -10C AT 00Z THU) WITH RELATIVELY SHALLOW MSTR BLO DGZ. EXPECT INCRSG LES ON WED NGT/THU WITH STRENGTHENING NNW FLOW BTWN DEPARTING CLIPPER LO AND ARCTIC HI PRES BLDG INTO SCNTRL CAN DRIVING H85 TEMPS AS LO AS -17C OVER LK SUP BY 00Z FRI. MODELS SHOW H925 WINDS BTWN 330-350 OR SO AND UP TO 30 KTS...WL HIT THE POPS UP HIEST IN THOSE AREAS FVRD BY THAT WIND DIRECTION. AT SOME POINT...A HEADLINE FOR LES WL LIKELY BE NECESSARY IN THESE FVRD AREAS WITH FCST SDNGS SHOWING CONSIDERABLE OMEGA WITHIN THE DGZ. WL MENTION IN THE HWO FOR NOW. WITH FALLING H85 TEMPS ON THU...EXPECT LTL DIURNAL RECOVERY IN TEMP. ONGOING LES/GUSTY WINDS ON THU NGT WL BEGIN TO DIMINISH W-E ON FRI WITH APRCH OF SFC RDG AXIS. PER NCEP GUIDANCE...TENDED TO FOLLOW THE QUICKER 00Z ECMWF/CNDN MODELS AND 12Z ECMWF FOR TIMING ARRIVAL OF RDG AXIS FM THE W AND ENDING OF THE LES. AS NEXT CLIPPER SHRTWV APRCHS FM THE W ON FRI NGT/SAT/SAT NGT...A STRONG WAD PATTERN WL SET UP ACRS THE UPR LKS TO THE NW OF DEPARTING SFC RDG AXIS. WL CARRY CHC POPS FOR -SN...WITH THE HIER POPS OVER NRN LK SUP/THE ERN FA CLOSER TO TRACK OF SFC LO PROGGED ACRS SRN ONTARIO AND WHERE THERE MAY BE SOME MOISTENING OFF LK MI. ANY SYNOPTIC SCALE SN WL END ON SUN WITH PASSAGE OF CLIPPER AND TRANSITION TO LES INTO MON WITH COLD AIR INFUSION (00Z ECMWF SHOWS H85 TEMP FALLING TO ARND -15C BY 12Z MON) IN THE WAKE OF CLIPPER LO. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... AT KCMX...VFR CIGS SHOULD TREND DOWN TO MVFR LATER IN THE NIGHT AS SUBSIDENCE INVERSION LOWERS WITH APPROACH OF HIGH PRES RIDGE. AS WINDS BACK LATE IN THE NIGHT/EARLY MORNING...MAY SEE OCCASIONAL MVFR VIS IN -SHSN AS FETCH ACROSS THE LAKE IMPROVES. LINGERING -SHSN SHOULD THEN END EARLY AFTN AS AIRMASS MODERATES/SFC HIGH PRES RIDGE ARRIVES. AS WINDS BACK SW LATE AFTN...VFR CONDITIONS WILL DEVELOP WITH LOSS OF OVERWATER FETCH. AT KSAW...UNDER NRLY WINDS...EXPECT WIDE SWINGS IN VIS/CIGS AS LONG FETCH ACROSS THE LAKE AND UPSLOPING RESULT IN HEAVIER SNOW SHOWERS AT TIMES FOR THE NEXT SEVERAL HRS. WHILE PREVAILING CONDITIONS SHOULD BE MVFR...HEAVIER SNOW SHOWERS WILL LIKELY RESULT IN PERIODIC IFR CONDITIONS UNTIL AROUND 10Z. WOULD NOT BE SURPRISED TO SEE A FEW BRIEF PERIODS OF LIFR. LATE IN THE NIGHT...LOWERING SUBSIDENCE INVERSION AND THE START OF BACKING WINDS WILL LEAD TO DIMINISHING -SHSN WITH MVFR CONDITIONS BECOMING THE RULE. FURTHER IMPROVEMENT TO VFR EXPECTED BY LATE MORNING AS WINDS BACK W. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... NORTH WINDS OF UP TO 30 KNOTS WILL DIMINISH TONIGHT INTO TUE MORNING AS A RIDGE OF HIGH PRESSURE CROSSES LAKE SUPERIOR. HOWEVER...ANOTHER LOW PRESSURE AREA REACHING NORTH DAKOTA TUESDAY EVENING IS EXPECTED TO CROSS JUST NORTH OF LAKE SUPERIOR ON WEDNESDAY...AND THEN MOVE TO THE LOWER GREAT LAKES BY THURSDAY. IN ITS WAKE FOR THURSDAY...A PERIOD OF NORTHERLY GALES TO 35 KNOTS IS POSSIBLE ON THURSDAY AS COLD AIR FLOWS SOUTH. FOR THURSDAY NIGHT INTO SATURDAY...ANOTHER RIDGE OF HIGH PRESSURE OVER THE PLAINS WILL BUILD BACK INTO UPPER MICHIGAN...BRINGING WINDS BACK DOWN BELOW GALES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUE MIZ005-006-085. LAKE EFFECT SNOW ADVY UNTIL 1 AM EST /MIDNIGHT CST/ TUE MIZ002-009. LAKE EFFECT SNOW ADVY UNTIL 7 AM EST TUE MIZ013. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ UPDATE...ROLFSON SYNOPSIS/SHORT TERM DISCUSSION...AJ LONG TERM DISCUSSION...KC AVIATION...ROLFSON MARINE...AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 356 AM CST TUE NOV 18 2008 .DISCUSSION... MAIN FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION. USED RUC TEMPERATURES TO UPDATE HOURLY GRIDS IN THE VERY NEAR TERM AS MODEL BEST DEPICTS CURRENT WARMING TREND. THEN...SHIFTED TO MAV/MET BLEND AS THERE EXISTS GOOD AGREEMENT BETWEEN GFS/NAM. FAVORED GFS QPF SINCE IT SHOWS A SIMILAR SOLUTION WITH UPCOMING CLIPPER SYSTEM TONIGHT INTO WEDNESDAY AS TO WHAT OCCURRED MONDAY AFTER THE FIRST CLIPPER PASSAGE. TODAY WILL BE WARMER AND BREEZY. BOTH GFS/NAM SHOW 850 HPA LOW MOVING ACROSS SOUTHERN MANITOBA THIS AFTERNOON WITH IMPRESSIVE WARM FRONT DRAPED TO THE SOUTH. 24 HOUR 850 HPA TEMPERATURE CHANGE EXPECTED TO BE UPWARDS 0F +10 DEGREES C...RESULTING IN MAXIMUM SURFACE TEMPERATURES 5-10 DEGREES WARMER THAN YESTERDAY. AT THE SAME TIME...RETURN SOUTHERLY FLOW WILL SET UP ON THE BACK-SIDE OF DEPARTING HIGH PRESSURE. WINDS PROGGED TO BE 25 TO 30 KTS IN THE 925-850 HPA LAYER...BUT CLOUD COVER SHOULD HELP INHIBIT BOUNDARY LAYER MIXING. NONETHELESS...STILL EXPECT BREEZY TO LOCALLY WINDY CONDITIONS THIS AFTERNOON FROM THE SOUTH...ESPECIALLY ALONG AND WEST OF THE RED RIVER VALLEY. TODAY EXPECTED TO BE DRY AS DEEPEST LOW-LEVEL MOISTURE REMAINS NORTH OF THE LOW AND CANADIAN BORDER. ATTENTION THEN TURNS TO TONIGHT INTO WEDNESDAY AS CLIPPER SYSTEM MOVES EASTWARD. LOW-LEVEL MOISTURE SEEPS SOUTHEASTWARD AND ACROSS PORTIONS OF NORTHWEST MINNESOTA. AS SUCH...THERE IS A SLIGHT CHANCE FOR -SHSN MAINLY ACROSS ROSEAU...LAKE OF THE WOODS AND BELTRAMI COUNTIES OVERNIGHT. IN ADDITION TO FLURRIES..DID INCLUDE LIGHT FREEZING DRIZZLE ACROSS MUCH OF NORTHWEST MINNESOTA FROM 06 TO 12 UTC TONIGHT. SOUNDING ANALYSIS SHOWS ELEVATED WARM LAYER FROM 700-800 HPA...WHICH MAY PROVIDE ENOUGH WARMING FOR MIXED PRECIPITATION AT THE SURFACE. COLD AIR ADVECTION TO RETURN WEDNESDAY WITH COLD FRONT ON BACK- SIDE OF DEPARTING CLIPPER SYSTEM. EXPECT INSTABILITY SNOW SHOWERS/FLURRIES ACROSS MOST OF THE FORECAST AREA THROUGHOUT THE DAY...ALTHOUGH ACCUMULATIONS WILL BE MINIMAL...ONE INCH OR LESS. WINDS WILL REMAIN STRONG AND SHIFT TO THE NORTHWEST WITH FRONTAL PASSAGE. THURSDAY AND FRIDAY LOOK TO BE DRY AS UPPER LEVEL RIDGE BEGINS TO MOVE EASTWARD...ALTHOUGH TEMPERATURES WILL REMAIN NEAR OR BELOW SEASONAL NORMALS. && .AVIATION... EXPECT VFR CONDITIONS AT ALL TAF SITES THROUGH AT LEAST 00 UTC TONIGHT. MAIN AVIATION CONCERN WILL BE STRONG SOUTHERLY WINDS AS RETURN FLOW DEVELOPS ON THE BACK-SIDE OF DEPARTING HIGH PRESSURE. EXPECT SUSTAINED WINDS FROM 15 TO 20 KTS WITH FREQUENT GUSTS FROM 25 TO 30 KTS TO DEVELOP THIS MORNING...CONTINUING THROUGH MUCH OF THE AFTERNOON. THERE IS A SLIGHT CHANCE FOR SNOW SHOWERS AND/OR FREEZING DRIZZLE AT KBJI OVERNIGHT...BUT WILL NOT MENTION IN 12 UTC TAF ISSUANCE DUE TO TIMING UNCERTAINTIES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ ROGERS nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 328 AM CST TUE NOV 18 2008 .SHORT TERM...TODAY THROUGH THURSDAY WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW UPPER LEVEL RIDGING CENTERED OVER THE ROCKIES AND BUILDING SLOWLY EAST. AT THE SURFACE...SOUTHERLY WINDS BEGINNING TO PICK UP A BIT AS HIGH PRESSURE CONTINUES TO MOVE EAST AND AWAY FROM THE REGION. ACROSS WESTERN CWA WINDS IN THE 15 TO 20 MPH RANGE WHILE ACROSS THE EAST THEY ARE APPROACHING 10 MPH. TEMPERATURES HAVE BECOME NEARLY STEADY OR HAVE RISEN A COUPLE DEGREES IN SOME LOCATIONS AS WARMER AIR CONTINUES TO MOVE INTO THE AREA. IMPRESSIVE WAA SPREADS OVER THE AREA TODAY AS SOUTHERLY WINDS INCREASE OUT AHEAD OF APPROACHING WARM FRONT. FOR EXAMPLE...06Z NAM SHOWS 850 MB TEMPS OF AROUND -2 C ACROSS THE JAMES VALLEY AT 12Z THIS MORNING...BUT WARMS UP TO +11 C BY LATE THIS AFTERNOON. WITH SOUTHERLY WINDS INCREASING...WILL BE ABLE TO MIX WARMER AIR DOWN TO THE SURFACE. WILL THEREFORE SEE WARMER TEMPS WITH A MAJORITY OF THE AREA SEEING 40S AND 50S. ACROSS THE FAR EASTERN CWA WHERE COOLER AIR WILL BE IN PLACE THE LONGEST TODAY...MAY ONLY SEE UPPER 30S FOR HIGHS. SOUTHERLY WINDS WILL INCREASE INTO THE BREEZY CATEGORY TODAY MAINLY EAST OF THE MISSOURI RIVER WITH SPEEDS RANGING FROM 15 TO 25 MPH. WARM FRONT WILL CONTINUE TO MOVE EAST THIS EVENING...REACHING THE MISSOURI RIVER BY AROUND 00Z AND THE I-29 CORRIDOR BY 06Z. SHOULD SEE TEMPS STEADY OUT THEN SLOWLY RISE TONIGHT AS WINDS SWITCH TO A WESTERLY DIRECTION BEHIND THE WARM FRONT. THIS PLAYS OUT IN THE TEMP GRIDS ALSO. THEN FOR WEDNESDAY...CAA SPREADS ACROSS THE AREA AS COLD FRONT DROPS SOUTH THROUGH THE DAKOTAS. CONSTRUCTED GRIDS TO SHOW A LATE MORNING OR EARLY AFTERNOON HIGH TEMPERATURE THEN AS CAA BECOMES MORE SUBSTANTIAL...SHOULD SEE TEMPS STEADY OUT OR SLOWLY FALL DURING THE AFTERNOON. BIGGEST PUSH OF CAA OCCURS BETWEEN 18Z AND 00Z WEDNESDAY. ATTENTION THEN TURNS TO LATE WEDNESDAY NIGHT AND THURSDAY AS A WEAK SHORTWAVE DROPS SOUTHEAST ACROSS THE AREA. NAM/GFS TRY TO SPIT OUT .01 QPF HERE AND THERE ACROSS EASTERN SD...SUGGESTING PERHAPS FLURRIES OR VERY LIGHT SNOW SHOWERS. SREF PROBS OF .01 SHOW NOTHING. NOT A LOT OF MOISTURE TO WORK WITH BUT BUFKIT SOUNDINGS SHOW BEST MOISTURE LATE WEDNESDAY NIGHT. BUFKIT GFS SOUNDING SHOWS LIGHT SNOW AT KABR AT 12Z THURSDAY WITH NEAR SATURATION IN SNOW GROWTH REGION. DURING THE DAY THURSDAY ONLY A SHALLOW LAYER OF MOISTURE AROUND 850MB...BUT FAIRLY STEEP LAPSE RATES BELOW THIS SHALLOW LAYER. NOT MUCH IN THE WAY OF LIFT EITHER BUT THERE IS A STRONG SURFACE HIGH MOVING IN WHICH COULD HELP TO SCOUR OUT A FEW FLURRIES. HAVE DECIDED TO ADD SCT FLURRIES FOR LATE WEDNESDAY NIGHT THROUGH THURSDAY AS THIS WAVE PASSES. .LONG TERM...00Z FRIDAY THROUGH MONDAY MAIN FCST CHALLENGE FOR THE EXTENDED DEALS WITH SORTING OUT MODEL SOLNS HEADING INTO THE WEEKEND. MODELS STILL REMAIN BASICALLY IN TWO CAMPS FOR THE EXTENDED FORECAST. THE GFS/UKMET/DGEX SOLN ALL POINT TOWARD STRONGER WAVE CRASHING OVER THE WRN CONUS RIDGE...CLOSED 5H/7H LOWS DROPPING INTO THE CWA FOR FRIDAY. THE EC/CANADIAN/ENSEMBLE MEMBERS AGREE WITH THIS WAVE CRASHING INTO THE RIDGE...BUT KEEP THE SYSTEM MORE OF AN OPEN WAVE AS IT TRAVERSES TO THE EAST. THE EC IS NOW TRENDED TO A BIT MORE ENERGY DROPPING SOUTH...MORE INTO ND THAN CANADA...AND THE LATEST RUN NOW PAINTS A BIT OF QPF ACROSS THE ERN DAKOTAS FOR THE DAY FRIDAY. GIVEN THAT CONFIDENCE IS LOW FOR ANY PARTICULAR SOLN...HAVE JUST KEPT WITH PERSISTANCE AND LEFT THE EXTENDED DRY FOR NOW. ALSO INTERESTING IS THAT THE EC IS NOW DROPPING THIS SYSTEM SOUTH INTO THE UPPER MIDWEST TO BEGIN NEXT WEEK...WHILE THE GFS MAINTAINS A ZONAL FLOW APPEARANCE ACROSS THE NRN TIER STATES. TEMP WISE...THE MODELS DO AGREE ON HIGH PRESSURE AT THE SFC BEING OVER THE REGION FOR THURSDAY NIGHT/FRIDAY MORNING. WITH SPEC HUMIDITIES LEANING TO MOCLEAR SKIES...THIS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING TO TAKE PLACE. HAVE LOWERED THURSDAY NIGHT LOWS BY A CATEGORY OR SO ACROSS THE CWA. OTHERWISE STUCK PRETTY CLOSE TO INHERITED MAX/MIN TEMP GRIDS DUE TO UNCERTAINITY IN THE MODELS. && .AVIATION... VFR CONDS ARE EXPECTED TO PERSIST THROUGH THE FCST PERIOD FOR ALL TERMINAL SITES. SCT-BKN080-100 CLOUDS WILL DRIFT NW TO SE ACROSS THE CWA THROUGH THE PERIOD. VSBYS WILL BE UNRESTRICTED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ SHORT TERM...TMT LONG TERM...HINTZ AVIATION...HINTZ WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 1105 PM CST MON NOV 17 2008 .AVIATION... NO CHANGES...VFR THRU PERIOD. CURRENT NORTHEAST WINDS WILL SLOWLY VEER TO THE SOUTHEAST BY TUESDAY AFTERNOON. 84 .UPDATE... 910 PM WEAK COLD FRONT NOW MOVING THROUGH THE I-20 CORRIDOR. HAVE UPDATED FORECAST TO INCLUDE SOME SLIGHTLY HIGHER NORTH/NORTHEAST WINDS BEHIND IT TONIGHT BASED ON UPSTREAM OBS/RUC FORECASTS. THIS WILL KEEP AIR MIXED UP WITH MIN TEMPS A LITTLE HIGHER THAN PREVIOUS NIGHTS. RAISED LOWS OVER THE WESTERN ZONES...OTHERWISE CHANGES WERE MAINLY COSMETIC. TR.92 && .AVIATION... 514 PM VFR THRU PERIOD. WIND SHIFT TO NORTH EXPECTED METROPLEX AROUND 02Z AND WACO 05Z. BY TUESDAY AFTN SFC RIDGE MOVES ON EAST AND FLOW WILL SWITCH BACK SOUTH. 84 && .PREV DISCUSSION... /ISSUED 200 PM CST MON NOV 17 2008/ SURFACE OBSERVATIONS THIS HOUR PLACE A COLD FRONT NEAR A LINE FROM LUBBOCK TO WICHITA FALLS TO JUST NORTH OF PARIS. TEMPERATURES ACROSS NORTH TEXAS ARE CURRENTLY IN THE 70S...WITH 50S AND 60S NOTED BEHIND THE FRONT. DEW POINT TEMPERATURES ARE VIRTUALLY THE SAME ON EITHER SIDE OF THE BOUNDARY. FRONTAL PASSAGE WILL OCCUR AFTER SUNSET FOR MOST OF THE REGION SO HIGH TEMPS WILL NOT BE AFFECTED MUCH. RADIATIONAL COOLING WILL NOT BE QUITE AS EFFECTIVE TONIGHT AS LAST NIGHT DUE TO SLIGHTLY HIGHER WIND SPEEDS. BY TOMORROW A COOLER AIRMASS WILL ARRIVE IN NORTH TEXAS...WITH HIGHS ONLY EXPECTED IN THE UPPER 50S TO MID 60S. SOUTH WINDS WILL RETURN WEDNESDAY ALLOWING AFTERNOON TEMPS TO INCREASE INTO THE LOWER 70S. INCREASING MOISTURE WILL ALSO HELP LOW TEMPS WEDNESDAY NIGHT/THURSDAY MORNING FROM DROPPING AS LOW AS PREVIOUS NIGHTS. MODELS INDICATE THAT A 1040 MB SURFACE HIGH WILL SLIDE SOUTH OUT OF CANADA ON THURSDAY BEHIND A STRONG COLD FRONT. THE ECMWF IS SLIGHTLY FASTER WITH THE RESULTANT FRONTAL PASSAGE THAN THE GFS. GIVEN THE DENSE NATURE OF THE AIRMASS...HAVE SIDED WITH THE ECMWF. IN ADDITION...THE GFS SEEMS TO BE HAVING TROUBLE RESOLVING THE SHALLOW COLD AIRMASS...AND THE RESULT HAS BEEN WIDE VARIATIONS IN TEMPERATURES FROM RUN TO RUN. THEREFORE HAVE FOLLOWED THE ENSEMBLE NUMBERS CLOSER THAN THE MAV MOS FOR THE LAST HALF OF THE FORECAST. NORTH TEXAS WILL STAY IN NORTHWEST/WEST FLOW ALOFT OVER THE WEEKEND. WEAK ISENTROPIC LIFT ALONG WITH ENERGY ASSOCIATED WITH A PASSING SHORTWAVE WILL PROVIDE A CHANCE FOR SHOWERS AND POSSIBLY A THUNDERSTORM SUNDAY. THE ECMWF INDICATES A BETTER CHANCE OF RAIN MONDAY AS A STRONG CLOSED LOW ROTATES INTO THE NORTHERN PLAINS... SENDING ANOTHER COLD FRONT OUR WAY. SH/13 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 46 63 47 75 54 / 0 0 0 0 5 WACO, TX 40 65 45 73 54 / 0 0 0 0 5 PARIS, TX 38 57 38 68 47 / 0 0 0 0 10 DENTON, TX 40 62 44 74 49 / 0 0 0 0 5 MCKINNEY, TX 40 60 41 71 49 / 0 0 0 0 5 DALLAS, TX 46 61 47 72 53 / 0 0 0 0 5 TERRELL, TX 41 60 43 71 52 / 0 0 0 0 5 CORSICANA, TX 41 62 42 72 53 / 0 0 0 0 5 TEMPLE, TX 42 67 45 73 53 / 0 0 0 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 1148 PM CST MON NOV 17 2008 .UPDATE...HAVE ALLOWED THE WINTER WX ADVSY TO EXPIRE. SATL HAS SHOWN A SLOW BUT STEADY WARMING TREND IN THE CLOUD TOPS OVER WSTRN LK SUPERIOR AND NC WI...AND SFC OBS INDICATED MAINLY LIGHT SNOW SHOWERS/FLURRIES LINGERING OVER VILAS COUNTY. REMAINING LES SHOULD END OVERNIGHT AS THE LLVL FLOW BACKS WEST AND DRIER AIR ARRIVES WITH THE SFC RIDGE. KIECKBUSCH && .PREV DISCUSSION...ISSUED AT 328 PM CST MON NOV 17 2008... SHORT TERM...TONIGHT AND TUESDAY... LATEST RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW A BROAD UPPER LEVEL RIDGE-TROUGH PATTERN FROM WEST TO EAST ACROSS NORTH AMERICA. MODEST SHORTWAVE CONTINUES TO DIVE WITHIN THE BACK SIDE OF THE UPPER TROUGH AS IT MAKES ITS WAY ACROSS NORTHERN WISCONSIN. DEEPER MOISTURE AND COLDER AIR ASSOCIATED WITH THE WAVE HAS HELPED PERSISTENT NNW OR NORTH LAKE EFFECT BANDS KEEP THEIR INTENSITY THROUGH MID-AFTERNOON. A COUPLE SURFACE TROUGHS HAVE BEEN EVIDENT ON RADAR AND THE SURFACE OBS WHICH HAVE ENHANCED THESE SNOW BANDS. ONE BAND DROPPED 1 TO 3 INCHES FROM VILAS THROUGH LINCOLN AND LANGLADE COUNTIES AS THE CONVERGENCE AXIS DROPPED SOUTH. ANOTHER CONVERGENCE AXIS HAS BEEN FEEDING AN ORGANIZED BAND ACROSS EASTER UPPER MICHIGAN AND HAS BEEN TRYING MOVE SW TOWARDS THE DOOR PENINSULA. OBVIOUSLY...LAKE EFFECT SNOW REMAINS THE MAIN FORECAST CONCERN. NORTH TO NNW LAKE EFFECT WILL CONTINUE THROUGH THE EVENING BUT CONDITIONS WILL TURN INCREASINGLY HOSTILE TOWARDS THE LONGEVITY OF THE BANDS. IMPRESSIVE OVER-LAKE INSTABILITY WITH DELTA T/S AROUND 20C WILL BE COUNTERACTED BY INCOMING 850-700MB DRY (FALLING FROM 70 TO 40 PCT) AND INCREASINGLY ANTICYCLONIC FLOW. WAS ALSO THINKING THE VERY LOW DEWPOINT AIR OVER THE ARROWHEAD AND SOUTHERN ONTARIO (SURFACE DEWPOINTS RANGING FROM 0-7F) WOULD SLOW LAKE EFFECT SNOW DEVELOPMENT...BUT HAVENT SEEN ANY IMPACT AS OF YET. THE LONGER FETCHES AS A RESULT OF THE MORE NORTHERLY FLOW SEEM TO NEGATING THIS FACTOR UNLIKE YESTERDAY. BUT AS THE DRIER AIR WORKS INTO THE AREA...THE LAKE EFFECT SNOW WILL TAKE AWHILE TO WIND DOWN...SO HAVE EXTENDED THE ADVISORY FOR VILAS COUNTY THROUGH THE EVENING. THINK THAT AN ADDITIONAL 1 TO 2 INCHES WILL FALL DURING THE EVENING AND ANOTHER HALF INCH OVERNIGHT. OTHERWISE...WILL HAVE SNOW SHOWERS THIS AFTERNOON DIMINISHING TO FLURRIES THIS EVENING AS THE CONVERGENCE AXIS OVER WISCONSIN WASHES OUT AND WE LOSE THE DIURNAL HEATING. WILL HAVE TO WATCH TO SEE IF THE OTHER CONVERGENCE AXIS OVER EASTERN LAKE SUPERIOR MAKES IT TO THE DOOR PENINSULA...WHICH COULD DROP A QUICK HALF INCH TO INCH OF SNOW. MODEL DATA SUGGEST IT WILL WASH OUT BEFORE REACHING WASHINGTON ISLAND BUT HAVE INCLUDED LIGHT SNOW SHOWERS THROUGH THE NIGHT ANYWAY. LOWS FROM THE LOW TEENS WEST TO LOW 20S EAST. HIGH PRESSURE BUILDS INTO NE WISCONSIN TOMORROW WITH MASSIVE HEIGHT RISES UNDERWAY ALOFT. PERHAPS SOME DIURNAL CU WILL HANG ON OR DEVELOP WITHIN THE LINGERING COLD AIRMASS NEAR LAKE MICHIGAN DURING THE MORNING. WARM ADVECTION KICKS IN DURING THE AFTERNOON WITH MID-LEVEL CLOUD COVER INVADING THE STATE. HIGHS RANGING FROM THE UPPER 20S NW TO THE MIDDLE 30S SE. LONG TERM...TUESDAY NIGHT THROUGH MONDAY. THE CHANCE OF ANOTHER SIGNIFICANT LAKE EFFECT EVEN WEDNESDAY NIGHT AND THURSDAY AND WHETHER OR NOT WE WILL BE ON THE NORTHERN FRINGE OF A WINTER STORM SUNDAY NIGHT AND MONDAY ARE THE TWO MAIN CHALLENGES FOR THIS PERIOD. A SHORTWAVE TROUGH MOVING THROUGH ON WEDNESDAY MAY CREATE SUFFICIENT MID LEVEL MOISTURE AND LIFT TO PRODUCE SOME LIGHT FREEZING DRIZZLE IN THE NORTH. THEN ANOTHER PUSH OF COLD AIR POURS INTO THE REGION SETTING UP SCATTERED SNOW SHOWERS AND LAKE EFFECT SNOW WEDNESDAY NIGHT AND THURSDAY. THINK THERE COULD BE ANOTHER ADVISORY CRITERIA SNOW EVENT IN VILAS COUNTY...AS WINDS AND TEMPERATURES ALOFT ARE CLOSE TO WHAT WE HAVE HAD TODAY. THE EVENT FOR SUNDAY NIGHT AND MONDAY DEPICTED BY THE ECMWF IS BEING OVERLOOKED FOR NOW...AS THERE ARE DIFFERENCES IN THE MEDIUM RANGE MODELS. IT ALSO LOOKS LIKE THE SURFACE AND 850MB LOWS ARE TOO FAR SOUTH FOR SIGNIFICANT SNOW IN OUR FORECAST AREA...DESPITE THE QPF AMOUNTS PREDICTED BY THE ECMWF. SO WILL WAIT AND SEE AND KEEO DRY FORECAST FOR NOW. AVIATION...OCCASIONAL LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO IMPACT RHI THROUGH THE EVENING. HEAVIEST BAND OF SNOW ENHANCED ALONG A SURFACE TROUGH AXIS...WHICH DROPPED VSBYS TO 1/4SM AT RHI EARLIER...HAS SHIFTED SOUTH OF THE TAF SITE. THIS BAND WILL WEAKEN AS IT BECOMES FARTHER REMOVED FROM LAKE SUPERIOR...BUT WILL HAVE POTENTIAL TO DROP VSBYS AT AUW/CWA TO IFR LEVELS MID TO LATE AFTERNOON. OTHERWISE...CENTRAL WI TAF SITES WILL SEE MVFR CIGS PREVAILING THROUGH EARLY EVENING WITH OCCASIONAL SNOW SHOWERS. LOW LEVEL MOISTURE SCOURS OUT OVERNIGHT AS HIGH PRESSURE MOVES INTO THE AREA...ENDING ANY LINGERING FLURRIES/SNOW SHOWERS AT THE TAF SITES. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 1028 AM EST TUE NOV 18 2008 .SYNOPSIS... THE REGION WILL REMAIN IN A COLD NORTH TO NORTHWEST FLOW THROUGH THE WORK WEEK WITH TEMPERATURES AVERAGING ABOUT 10 DEGREES BELOW NORMAL. && .NEAR TERM /THROUGH 6 PM EST TUESDAY/... OUR REGION WILL LIE WITHIN A WEAK DEFORMATION AREA TO THE N OF A MID LEVEL SHORTWAVE...BEST DEPICTED BY THE RUC13 AROUND 700 MB. THIS MID LEVEL FORCING...COMBINED WITH SLIGHT LOW LEVEL MOISTURE/INSTABILITY ENHANCEMENT FROM A NNE FLOW OFF LAKE CHAMPLAIN SHOULD ALLOW SNOW SHOWERS TO PERSIST ACROSS THE UPPER HUDSON VALLEY REGION...AND EXPANDING INTO SOUTHERN VT THROUGH THE MID AFTERNOON HOURS. THUS...WE HAVE INCREASED POPS INTO THE LOW LIKELY RANGE FOR THIS REGION...WITH MINOR ACCUMS OF AN INCH OR TWO POSSIBLE WITHIN THE MORE PERSISTENT SNOW SHOWERS. ELSEWHERE...SCATTERED SNOW SHOWERS/FLURRIES WILL DEVELOP FURTHER S AND SE DURING THE AFTERNOON HOURS. OTHERWISE...NO CHANGES TO TEMPS...ALTHOUGH HAVE INCREASED DEWPOINTS A FEW DEGREES FROM THE MOHAWK RIVER NORTH AND NORTHEAST...BASED ON CURRENT OBS. && .SHORT TERM /TUE NIGHT THROUGH THURSDAY/... WEAK RIDGING BUILDS INTO THE AREA LATER TONIGHT INTO WEDNESDAY. IT WILL VERY SHORT LIVED AS YET ANOTHER SHORT WAVE DIVES SOUTHEAST OUT OF CANADA REINFORCING LONG WAVE TROUGH OVER REGION. A WEAK LOW PRESSURE SYSTEM WILL APPROACH THE REGION FROM THE GREAT LAKES WEDNESDAY NIGHT. HOWEVER...ON THURSDAY THIS SYSTEM WILL ITS IDENTITY AND GET ABSORBED INTO THE LARGE SCALE FLOW AS ANOTHER SHORT WAVE DIVES INTO THE TROUGH. BY THURSDAY EVENING THERE WILL BE DEEP CYCLONIC FLOW ACROSS REGION. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AN UPPER LEVEL TROF WILL REMAIN ENTRENCHED ACROSS THE REGION FOR THE END OF THE WORK WEEK AND INTO THE FIRST HALF OF THE WEEKEND. THIS PATTERN WILL CONTINUE TO RESULT IN BELOW NORMAL TEMPS AND ISOLATED TO SCATTERED LAKE EFFECT/UPSLOPE SNOW SHOWERS...MAINLY WEST OF ALBANY. A RIDGE OF HIGH PRESSURE IS FORECAST TO BRIEFLY BUILD ACROSS THE REGION ON SUNDAY...HOWEVER THIS WILL BE SHORT LIVED AS THE NEXT SYSTEM APPROACHES LATE SUNDAY NIGHT INTO MONDAY. THERE IS QUITE A BIT OF UNCERTAINTY AS TO THE POSSIBLE SYSTEM FOR EARLY NEXT WEEK. THE GFS HAS BEEN CONSISTENTLY INDICATING THE PASSAGE OF A CLIPPER TYPE SYSTEM WITH A SHORT WAVE TROF MOVING THROUGH. HOWEVER...THE ECMWF CONTINUES TO DEPICT A STORMIER SCENARIO...WITH A CLOSED UPPER LOW BARRELING EASTWARD ACROSS THE GREAT LAKES AS A WARM FRONT BRINGS SIGNIFICANT WINTRY PRECIP TO THE NORTHEAST ON MONDAY. THIS SOLUTION HAS SHOWN SOME RUN TO RUN CONSISTENCY...AND SOME GFS ENSEMBLE MEMBERS HINTING AT POTENTIAL SIGNIFICANT QPF. FOR NOW WILL GO SOMEWHAT ABOVE GMOS GUIDANCE AND MENTION CHANCE POPS. STILL PLENTY OF TIME TO SORT OUT DETAILS AS WE GET CLOSER TO THE POTENTIAL EVENT. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... A COLD NORTHERLY FLOW WILL PERSIST FOR THE NEXT 24 HOURS...WITH CYCLONIC FLOW ALOFT KEEPING PLENTY OF CLOUDS AROUND THROUGHOUT THE MORNING AND AFTERNOON. CIGS EXPECTED TO REMAIN IN VFR RANGE THOUGH. ONLY POSSIBLE ISSUE MAY BE SOME LIGHT SNOW SHOWERS OR FLURRIES COMING OFF LAKE CHAMPLAIN POTENTIALLY AFFECTING KGFL THIS AFTERNOON. HAVE INDICATED A VCSH BETWEEN 18Z/TUE TO 00Z/WED FOR NOW...WITH A LOW PROBABILITY OF OCCURRENCE. SKIES WILL TEND TO CLEAR THIS EVENING AS HIGH PRESSURE BUILDS IN FROM THE WEST. WINDS WILL BE NORTHERLY AROUND 5 KT OR LESS THROUGH MID MORNING...THEN INCREASING TO AROUND 10 KT. OUTLOOK... WED...VFR...NO SIG WX. THU...VFR...SLGT CHC -SHSN AND ASSOC MVFR. FRI-SAT...VFR...NO SIG WX. && .FIRE WEATHER... |* ADD DISCUSSION HERE. *| && .HYDROLOGY... A COLD AIR MASS WILL REMAIN IN PLACE ACROSS REGION FOR THE NEXT SEVERAL DAYS. NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE REST OF THE WEEK...WITH JUST ISOLATED TO SCATTERED SNOW SHOWERS MAINLY WEST OF ALBANY. PORTIONS OF THE ADIRONDACKS DID RECEIVE AROUND ONE HALF INCH OF WATER EQUIVALENT DURING THE PAST 24 HOURS ASSOCIATED WITH HEAVY LAKE EFFECT SNOW. HOWEVER...LITTLE OR NO SNOW MELT IS ANTICIPATED WITH COLD TEMPERATURES PERSISTING. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...IAA NEAR TERM...KL/IAA SHORT TERM...KL/IAA LONG TERM...JPV AVIATION...JPV FIRE WEATHER... HYDROLOGY...JPV ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 633 AM CST TUE NOV 18 2008 .DISCUSSION... 430 AM CST INTENSE LAKE EFFECT SNOW BAND HAD BACKED UP INTO PORTER AND EASTERN LAKE COUNTIES OF NORTHWEST INDIANA DURING THE VERY EARLY MORNING. LATEST NAM12 AND RUC13 MODEL RUNS CONTINUE TO DEPICT THIS BAND WELL...KEEPING AXIS OVER PORTER AND EASTERN LAKE COUNTIES SOUTH ACROSS THE KANKAKEE RIVER INTO JASPER AND NORTHEASTERN NEWTON COUNTIES THROUGH MID MORNING. VERY COLD MID LEVEL AIR IN WAKE OF THE SHORT WAVE TROUGH THAT DROPPED SOUTHEAST ACROSS THE REGION LAST EVENING HAS ALLOWED CLOUD TOPS OF THE LAKE EFFECT BAND TO APPROACH 20K FT IN DEPTH PER RADAR. EXPECT MODERATE TO HEAVY LAKE EFFECT TO PERSIST IN FAR NORTHWEST INDIANA WITH LIGHTER SNOW SHOWERS AS FAR WEST AS THE ILLINOIS STATE LINE. WEB CAM ON 80/94 AT RIPLEY HAS BEEN SHOWING PERIODS OF HEAVY SNOW WITH SNOW COVERED HIGHWAY. BAND DEPICTED SHIFTING BACK TOWARD THE EASTERN SIDE OF THE LAKE BY LATE MORNING WITH BACKING OF LOW LEVEL SYNOPTIC FLOW...AND INTENSITY OF SNOWFALL FROM THE BAND WILL BE DIMINISHING AS MID LEVEL WARMING CAUSES IN A LOWERING OF THE EQUILIBRIUM LEVEL AND RESULTS IN LESS VIGOROUS CONVECTION OVER THE LAKE. THE SURFACE RIDGE CURRENTLY LOCATED OVER MINNESOTA...IOWA AND MISSOURI WILL CONTINUE TO SHIFT EASTWARD ACROSS THE MIDWEST TODAY KEEPING SKIES...OUTSIDE OF THE LAKE EFFECT AREAS...SUNNY FOR A WHILE BEFORE HIGH AND MID LEVEL CLOUDS START TO INVADE FROM THE NORTHWEST THIS AFTERNOON WITH THE MID LEVEL WARM ADVECTION IN ADVANCE OF A SHORT WAVE TOPPING THE WESTERN NORTH AMERICAN UPPER RIDGE. THIS SHORT WAVE TO DROP SOUTHEAST ACROSS SASKATCHEWAN AND MANITOBA AND REACH WESTERN ONTARIO BY WEDNESDAY MORNING. LOW LEVEL WINDS BACK TO SOUTHWEST AS THE RIDGE CONTINUES TO THE EAST AND THE LOW ASSOCIATED WITH THE SHORT WAVE MOVES JUST NORTH OF THE ONTARIO- MINNESOTA BORDER. SOUTHWEST WINDS AND AT LEAST PARTLY SUNNY SKIES SHOULD ALLOW TEMPS ON WEDNESDAY TO PUSH INTO THE LOWER AND MID 40S BEFORE THE COLD FRONT TRAILING FROM THE LOW PASSES THROUGH THE FORECAST AREA LATE WEDNESDAY AFTERNOON AND EVENING. THIS RETURNS THE REGION TO DEEP NORTHWEST FLOW AND COLD AIR ADVECTION. ANOTHER SHORT WAVE TO DROP ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES THURSDAY AND THURSDAY NIGHT WITH REINFORCING COLD AIR BUT LITTLE THREAT OF SIGNIFICANT SNOW SAVE FOR LAKE EFFECT AREAS OF LOWER MI AND NORTHERN INDIANA. WITH COLD FLOW REGIME BACK...DAYTIME TEMPS RESTRICTED TO ONLY THE 30S THURSDAY AND FRIDAY. LATEST GFS SEEMS TO BE ALONE IN DROPPING A SHORT WAVE AND ACCOMPANYING SURFACE LOW ALONG WITH A STRIPE OF ACCUMULATING SNOW INTO THE MID MISSISSIPPI VALLEY LATE FRIDAY NIGHT AND SATURDAY SO HAVE MAINTAINED DRY FORECAST FOR NOW. TRS && .AVIATION... 1200 UTC TAFS... 612 AM CST THE WIND DIRECTION FOR THE AIRPORTS IN NORTH CENTRAL...NORTHEAST ILLINOIS AND NORTHWEST INDIANA WILL BE RESULTING FROM THE MOVEMENT OF A LARGE HIGH OVER IOWA THIS MORNING. THERE WILL BE A NORTH WIND AT THE AIRPORTS THIS MORNING. THE HIGH WILL MOVE SOUTH TO WESTERN KENTUCKY BY THIS EVENING. THERE WILL BE A SOUTH WIND AFTER 22 UTC AT THE AIRPORTS. A LOW WILL MOVE INTO NORTH DAKOTA THIS MORNING. THE PRESSURE GRADIENT BETWEEN THE HIGH AND LOW WILL BE LARGE ENOUGH TO GIVE 14 TO 19 KNOT WIND LATE MORNING AND EARLY AFTERNOON. WE EXPECT VFR CLOUDS TODAY. THERE WILL BE A TEN THOUSAND FOOT CEILING BY THIS EVENING. && .MARINE... 314 AM CST A LARGE HIGH WAS OVER MINNESOTA AND IOWA THIS MORNING. A WEAK LOW WAS OVER SOUTHWEST MICHIGAN. THIS LOW IS PART OF THE LAKE EFFECT SNOW OVER NORTHWEST INDIANA AND SOUTHWEST MICHIGAN. ANOTHER LOW WAS AT 38 NORTH LATITUDE AND 74 WEST LONGITUDE. THIS LOW...OFF THE COAST OF NEW JERSEY...AND THE HIGH ARE PROVIDING THE NORTH WIND ON LAKE MICHIGAN THIS MORNING. THE HIGH WILL MOVE SOUTHEAST TO WESTERN KENTUCKY BY THIS EVENING. A LOW WILL DEVELOP IN NORTH DAKOTA AND WILL MOVE TO EASTERN LAKE SUPERIOR BY WEDNESDAY AFTERNOON. BY THURSDAY EVENING...A LARGE HIGH WILL MOVE TO CENTRAL MANITOBA AND SPREAD SOUTH TO OKLAHOMA. WE EXPECT NO FREEZING SPRAY THIS MORNING OR TUESDAY NIGHT. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...LAKE EFFECT SNOW WARNING...INZ001-INZ002 UNTIL NOON TUESDAY. LAKE EFFECT SNOW ADVISORY...INZ010-INZ011 UNTIL NOON TUESDAY. LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA && $$ il AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GRAND FORKS ND 1012 AM CST TUE NOV 18 2008 .DISCUSSION... MAIN FORECAST CHALLENGE FOR TODAY IS THE HIGH TEMPERATURE FORECAST. QUITE A BIT OF MID AND HIGH LEVEL CLOUDINESS OVER THE AREA NOW...ALTHOUGH SOME IS THIN. SO WILL LIKELY NOT SEE A LOT OF SUN TODAY. QUITE A BIT OF WARM AIR TO THE WEST...WITH 50F AND HIGHER SFC TEMPS AT 10 AM AT MANY LOCATIONS OVER CENTRAL MT. 850MB TEMP GRADIENT ALSO EXTREMELY TIGHT...WITH KGGW AT +17C/KBIS AT +4C/ AND KINL AT -10C. THIS WARM AIR AT 850MB WILL BE SLOWLY WORKING TO THE EAST TODAY...DUE TO THE WIND DIRECTION SWITCHING AROUND TO THE SOUTHWEST AND THEN WEST THIS AFTERNOON. THIS WILL ALLOW THE WARM AIR TO MOVE IN ALOFT...BUT THE SFC WILL BE ANOTHER STORY. THE SFC LOW IS NOT EXPECTED TO MOVE INTO THE NORTH CENTRAL PART OF ND UNTIL AROUND 00Z WED. THEREFORE THE FA WILL BE IN FAIRLY GUSTY SOUTH WINDS TODAY WHICH WILL KEEP MUCH COOLER AIR NEAR THE SFC. THINK THE HIGHEST TEMPS SHOULD BE IN THE WEST TODAY...AND INHERITED FORECAST ALREADY HAD THIS COVERED. WILL LEAVE TEMPS AS IS...BUT WILL BUMP UP CLOUD COVER A LITTLE. FOR TONIGHT...WEAK SFC LOW STILL ON TARGET TO TRACK ACROSS THE NORTHERN FA AND TOWARD KDLH BY 12Z WED. MODELS...ESPECIALLY THE GFS...HAVE BACKED OFF ON QPF AREA AND AMOUNTS. LOOKS LIKE IF ANY PCPN FALLS IT WOULD BE IN THE NORTHEAST FA. WILL TAKE ANOTHER LOOK AT PCPN TYPES FOR TONIGHT WITH THE AFTERNOON FORECAST PACKAGE... BUT NOT LOOKING TOO FAVORABLE FOR FREEZING DRIZZLE IN THE NORTHEAST. MODELS SHOWING MOST OF THE LIGHT QPF OCCURRING IN THE COLDER AIR...WHICH WOULD KEEP THE PCPN AS FLURRIES/VERY LIGHT SNOW. && .AVIATION... EXPECT VFR CONDITIONS AT ALL TAF SITES THROUGH AT LEAST 00 UTC TONIGHT. MAIN AVIATION CONCERN WILL BE STRONG SOUTHERLY WINDS AS RETURN FLOW DEVELOPS ON THE BACK-SIDE OF DEPARTING HIGH PRESSURE. EXPECT SUSTAINED WINDS FROM 15 TO 20 KTS WITH FREQUENT GUSTS FROM 25 TO 30 KTS TO DEVELOP THIS MORNING...CONTINUING THROUGH MUCH OF THE AFTERNOON. THERE IS A SLIGHT CHANCE FOR SNOW SHOWERS AND/OR FREEZING DRIZZLE AT KBJI OVERNIGHT...BUT WILL NOT MENTION IN 12 UTC TAF ISSUANCE DUE TO TIMING UNCERTAINTIES. && .PREV DISCUSSION... /ISSUED 356 AM CST TUE NOV 18 2008/ MAIN FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION. USED RUC TEMPERATURES TO UPDATE HOURLY GRIDS IN THE VERY NEAR TERM AS MODEL BEST DEPICTS CURRENT WARMING TREND. THEN...SHIFTED TO MAV/MET BLEND AS THERE EXISTS GOOD AGREEMENT BETWEEN GFS/NAM. FAVORED GFS QPF SINCE IT SHOWS A SIMILAR SOLUTION WITH UPCOMING CLIPPER SYSTEM TONIGHT INTO WEDNESDAY AS TO WHAT OCCURRED MONDAY AFTER THE FIRST CLIPPER PASSAGE. TODAY WILL BE WARMER AND BREEZY. BOTH GFS/NAM SHOW 850 HPA LOW MOVING ACROSS SOUTHERN MANITOBA THIS AFTERNOON WITH IMPRESSIVE WARM FRONT DRAPED TO THE SOUTH. 24 HOUR 850 HPA TEMPERATURE CHANGE EXPECTED TO BE UPWARDS 0F +10 DEGREES C...RESULTING IN MAXIMUM SURFACE TEMPERATURES 5-10 DEGREES WARMER THAN YESTERDAY. AT THE SAME TIME...RETURN SOUTHERLY FLOW WILL SET UP ON THE BACK-SIDE OF DEPARTING HIGH PRESSURE. WINDS PROGGED TO BE 25 TO 30 KTS IN THE 925-850 HPA LAYER...BUT CLOUD COVER SHOULD HELP INHIBIT BOUNDARY LAYER MIXING. NONETHELESS...STILL EXPECT BREEZY TO LOCALLY WINDY CONDITIONS THIS AFTERNOON FROM THE SOUTH...ESPECIALLY ALONG AND WEST OF THE RED RIVER VALLEY. TODAY EXPECTED TO BE DRY AS DEEPEST LOW-LEVEL MOISTURE REMAINS NORTH OF THE LOW AND CANADIAN BORDER. ATTENTION THEN TURNS TO TONIGHT INTO WEDNESDAY AS CLIPPER SYSTEM MOVES EASTWARD. LOW-LEVEL MOISTURE SEEPS SOUTHEASTWARD AND ACROSS PORTIONS OF NORTHWEST MINNESOTA. AS SUCH...THERE IS A SLIGHT CHANCE FOR -SHSN MAINLY ACROSS ROSEAU...LAKE OF THE WOODS AND BELTRAMI COUNTIES OVERNIGHT. IN ADDITION TO FLURRIES..DID INCLUDE LIGHT FREEZING DRIZZLE ACROSS MUCH OF NORTHWEST MINNESOTA FROM 06 TO 12 UTC TONIGHT. SOUNDING ANALYSIS SHOWS ELEVATED WARM LAYER FROM 700-800 HPA...WHICH MAY PROVIDE ENOUGH WARMING FOR MIXED PRECIPITATION AT THE SURFACE. COLD AIR ADVECTION TO RETURN WEDNESDAY WITH COLD FRONT ON BACK- SIDE OF DEPARTING CLIPPER SYSTEM. EXPECT INSTABILITY SNOW SHOWERS/FLURRIES ACROSS MOST OF THE FORECAST AREA THROUGHOUT THE DAY...ALTHOUGH ACCUMULATIONS WILL BE MINIMAL...ONE INCH OR LESS. WINDS WILL REMAIN STRONG AND SHIFT TO THE NORTHWEST WITH FRONTAL PASSAGE. THURSDAY AND FRIDAY LOOK TO BE DRY AS UPPER LEVEL RIDGE BEGINS TO MOVE EASTWARD...ALTHOUGH TEMPERATURES WILL REMAIN NEAR OR BELOW SEASONAL NORMALS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GODON nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1108 AM EST TUE NOV 18 2008 .SYNOPSIS... DRY WEATHER IS EXPECTED THROUGH MIDWEEK AS BROAD HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY TONIGHT AND WEDNESDAY. ANOTHER UPPER LEVEL DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES THURSDAY/THURSDAY NIGHT...BRINGING THE CHANCE FOR SCATTERED SNOW SHOWERS OR FLURRIES AND A REINFORCING SHOT OF ARCTIC AIR INTO THE REGION FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RUC SFC ANALYSIS INDICATED A 1038 MB HIGH CENTERED ALONG THE AR/TN BORDER WITH LOW PRESSURE EXITING EAST OF THE MID- ATLANTIC. AT THE MID-LEVELS...AN H5 CLOSED LOW IS DIPPING SEWD INTO THE MID-ATLANTIC...WITH A TROF AXIS EXTENDING FROM ERN CANADA INTO THE CAROLINAS. NRLY-NWRLY FLOW CONTINUES TO INDUCE LAKE EFFECT SNOW OFF OF ERIE AND MICHIGAN...ALTHOUGH SNOW SHOWERS ARE LIMITED TO AREAS CLOSER TO THE LAKES. DRIER AIR IS ADVECTING IN FROM THE NW...WITH TDS DROPPING INTO THE MID TO UPPER TEENS ACROSS A MAJORITY OF THE CWA. TEMPS THIS MORNING RANGED FROM THE U20S ACROSS THE NWRN THIRD OF THE CWA TO THE L30S ACROSS MUCH OF THE REST OF THE CWA. THIS AFTERNOON...H5 LOW WILL EXIT THE MID-ATLANTIC AS THE SFC HIGH WILL BEGIN TO BUILD IN FROM THE SOUTHWEST. A FEW LIGHT SNOW SHOWERS OFF OF LAKE ERIE MAY CLIP THE NERN CWA AS NRN FETCH OFF OF LAKE ERIE BECOMES MORE NWRN. UPDATED GRIDS TO A ADD A SLGT CHC SHSN FOR LICKING AND FAIRFIELD COUNTIES. NRLY-NWRLY FLOW WILL ALLOW FOR PTLY-MSTLY SUNNY SKIES ACROSS THE CWA...WITH DECREASED CLOUD COVERAGE AS HIGH BUILDS IN FROM THE SW. CONTINUED CAA FROM THE NW WITH 850 TEMPS APPROX -12C WILL ONLY ALLOW TEMPS TO WARM INTO THE L30S ACROSS THE NRN HALF OF THE CWA AND M30S FOR AREAS ALONG AND SOUTH OF THE OHIO RIVER. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... LO LVL WAA WILL DVLP ON WED AS SRLY FLO SETS UP ON THE BACK SIDE OF SFC HI PRES RIDGE. GFS/NAM BOTH INDCG STRONG CROSS CONTOUR ISENT LIFT AT 290K LVL AND ABV BY MIDDAY WED INTO THE AFTN HOURS...INDCG MID LVL CLOUD ENHANCEMENT COURTESY OF WAA REGIME. TAKEN VERBATIM...DEPTH OF MID LVL MOISTURE AND AVAIL LIFT FROM BOTH MODELS STRONGLY SUGGESTING FAIRLY THICK CLOUD DECK FOR WED AFTN FOR MUCH OF THE FCST AREA. HAVE INCREASED TO PTLY TO MSTLY CLDY FOR AFTN HOURS FOR AREAS ALONG AND NORTH OF THE OHIO RIVER. AS DEEPER MID LVL ISENT LIFT DEPARTS TO EAST OF REGION BY WED EVNG...MID CLOUDS LKLY TO BE REPLACED BY SC DECK AS AFOREMENTIONED SFC LO DROPS SOUTHEAST ACRS CNTRL GRT LKS WED NIGHT. A DRY COLD FRONT ASSOCD WITH THE SFC LO WILL PASS THRU FCST AREA LATE WED NIGHT...PROVIDING A REINFORCING SHOT OF COLDER AIR TO THE OH VLY. CERTAINLY POSSIBLE FOR A FEW FLURRIES WITH FROPA WED NIGHT BUT DEEP MOISTURE LACKING TO SOME EXTENT WITH PASSAGE OF FRONT. UPR TROF RELOADS IN WAKE OF SFC LO/FRONT WITH 00Z MODELS GENERALLY FAVORING A DEEPER AND FURTHER WEST TROF OVER THE GRT LKS FOR THURS/THURS NIGHT. LO LVL CAA AND NW FLO ON THURS OPENING DOOR FOR DOWNWIND LK EFFECT SNOW BANDS TO AFFECT FCST AREA ONCE AGAIN WITH SCT -SHSN/FLURRIES ACRS ENTIRE FCST AREA. A CLOSER LOOK AT MODEL SOUNDING DATA INDCG SIMILAR BNDRY LYR CONDITIONS TO MONDAY IN PLACE WITH STEEPENING LO LVL LAPSE RATES AND SHALLOW INSTABILITY. HAVE THEREFORE BUMPED UP TO 20/30 POPS FOR SCT -SHSN ON THURS ACRS ENTIRE FCST AREA. HIGHEST POPS WILL BE ACRS NORTHEAST THIRD OF FCST AREA WHERE FAVORABLE 290-300 DEG WIND DIR SHOULD ENABLE LK MICHIGAN BANDS TO WORK INTO WEST CNTRL/CNTRL OH DURING AFTN HOURS. MAINTAIN POPS INTO THURS NIGHT AS TRAILING SFC TROF AND S/WV DIVE ACRS REGION. TEMPS...UNDERCUT MOS GUID THRU ENTIRE SHORT TERM PERIOD. EXPECTED MID LVL CLOUDS ON WED LKLY TO KEEP TEMPS IN THE U30S/L40S ACRS FCST AREA. EXPECT EVEN COLDER TEMPS THURS WITH 850 TEMPS DROPPING TO NEAR -10C WITH MUCH OF THE FCST AREA REMAINING IN THE 35-40 DEG RANGE. LOWS WILL REMAIN IN THE 20S FOR BOTH WED/THURS NIGHTS. && .LONG TERM /FRIDAY THROUGH MONDAY/... SURFACE HIGH PRESSURE WILL BUILD INTO THE REGION AND SHOULD PROVIDE FOR DRY WEATHER CONDITIONS FRIDAY INTO SATURDAY BUT WITH SEASONABLY COLD AIRMASS IN PLACE...EXPECT TEMPERATURES TO REMAIN BELOW NORMAL INTO THE WEEKEND. RIGHT NOW IT LOOKS LIKE SURFACE HIGH WILL BE CENTERED CLOSE TO OUR AREA BY SATURDAY MORNING...SO EXPECT THE COLDEST NIGHT TO BE FRIDAY NIGHT WITH MANY LOCATIONS DROPPING TO NEAR 20 DEG. WITH 850 TEMPS NEAR -15C FRI...HAVE LOWERED AFTN HIGHS INTO THE L/M30S. SAT HIGHS WILL ONLY BE A FEW DEG WARMER IN THE U30S/L40S. SIGNIFICANT MODEL DISCREPANCIES CONTINUE TO EXIST FOR THE LAST PART OF THE LONG TERM PERIOD. THE ECMWF IS TRENDING STRONGER WITH SHORT WAVE ENERGY DROPPING DOWN THROUGH THE NORTHERN PLAINS SUNDAY INTO MONDAY WHILE THE GFS REMAINS CONSIDERABLY WEAKER. SINCE THE ECMWF HAS BEEN A LITTLE MORE CONSISTENT WITH THIS FOR THE LAST FEW RUNS...WILL LEAN CLOSER TO IT BUT STILL KEEP POPS FAIRLY LOW SUNDAY INTO MONDAY DUE TO THE UNCERTAINTY. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... SKIES WILL BE PARTLY TO MOSTLY CLOUDY THROUGH 23Z AS CUMULUS AND STRATOCUMULUS DEVELOP DURING THE HEATING OF THE DAY DUE TO THE COLD UNSTABLE AIRMASS IN PLACE ACROSS THE REGION. LOCAL MVFR CIGS CAN BE EXPECTED THROUGH 15Z...OTHERWISE VFR CONDITIONS WILL PREVAIL FOR THE REMAINDER OF THE TAF PERIOD. SFC HIGH PRESSURE IS FORECAST TO BUILD INTO THE REGION BETWEEN 00Z AND 12Z WEDNESDAY...THEN MOVE EAST OF THE REGION BY 18Z WEDNESDAY. THIS HIGH WILL CLEAR OUT/DISSIPATE REMAINING STRATOCUMULUS CLOUDS THIS EVENING. HOWEVER...MID AND HIGH LVL CLOUDS ARE FORECAST TO SPILL ACROSS THE REGION BETWEEN 06Z AND 12Z. OUTLOOK...MVFR CIGS POSSIBLE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...WOODRUM SHORT TERM...RYAN LONG TERM...JGL/RYAN AVIATION...HICKMAN oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1146 AM CST TUE NOV 18 2008 .UPDATE... 1135 AM CST WILL ALLOW LAKE EFFECT SNOW WARNINGS TO EXPIRE AS SCHEDULED AT 18Z. LAKE EFFECT MACHINE SLOWLY WINDING DOWN LATE THIS MORNING AS INVERSION HEIGHTS ARE QUICKLY LOWERING. RADAR TRENDS HAVE SHOWN A GRADUAL DE-ORGANIZATION OF THE SNOW SHOWERS WITH LESS AND LESS INLAND PENETRATION OVER THE PAST COUPLE HOURS. WHILE A BRIEF MODERATE SNOW SHOWER IS STILL POSSIBLE INTO THE EARLY AFTERNOON...FEEL FAIRLY CONFIDENT THAT ANY ADDITIONAL ACCUMULATIONS WILL BE AN INCH OR LESS GIVEN THE RECENT TRENDS IN RADAR/SATELLITE REPRESENTATION OF THE LES. UPDATED GRIDS/TEXT PRODUCTS WILL BE ISSUED BY NOON. IZZI && .PREV DISCUSSION... 430 AM CST INTENSE LAKE EFFECT SNOW BAND HAD BACKED UP INTO PORTER AND EASTERN LAKE COUNTIES OF NORTHWEST INDIANA DURING THE VERY EARLY MORNING. LATEST NAM12 AND RUC13 MODEL RUNS CONTINUE TO DEPICT THIS BAND WELL...KEEPING AXIS OVER PORTER AND EASTERN LAKE COUNTIES SOUTH ACROSS THE KANKAKEE RIVER INTO JASPER AND NORTHEASTERN NEWTON COUNTIES THROUGH MID MORNING. VERY COLD MID LEVEL AIR IN WAKE OF THE SHORT WAVE TROUGH THAT DROPPED SOUTHEAST ACROSS THE REGION LAST EVENING HAS ALLOWED CLOUD TOPS OF THE LAKE EFFECT BAND TO APPROACH 20K FT IN DEPTH PER RADAR. EXPECT MODERATE TO HEAVY LAKE EFFECT TO PERSIST IN FAR NORTHWEST INDIANA WITH LIGHTER SNOW SHOWERS AS FAR WEST AS THE ILLINOIS STATE LINE. WEB CAM ON 80/94 AT RIPLEY HAS BEEN SHOWING PERIODS OF HEAVY SNOW WITH SNOW COVERED HIGHWAY. BAND DEPICTED SHIFTING BACK TOWARD THE EASTERN SIDE OF THE LAKE BY LATE MORNING WITH BACKING OF LOW LEVEL SYNOPTIC FLOW...AND INTENSITY OF SNOWFALL FROM THE BAND WILL BE DIMINISHING AS MID LEVEL WARMING CAUSES IN A LOWERING OF THE EQUILIBRIUM LEVEL AND RESULTS IN LESS VIGOROUS CONVECTION OVER THE LAKE. THE SURFACE RIDGE CURRENTLY LOCATED OVER MINNESOTA...IOWA AND MISSOURI WILL CONTINUE TO SHIFT EASTWARD ACROSS THE MIDWEST TODAY KEEPING SKIES...OUTSIDE OF THE LAKE EFFECT AREAS...SUNNY FOR A WHILE BEFORE HIGH AND MID LEVEL CLOUDS START TO INVADE FROM THE NORTHWEST THIS AFTERNOON WITH THE MID LEVEL WARM ADVECTION IN ADVANCE OF A SHORT WAVE TOPPING THE WESTERN NORTH AMERICAN UPPER RIDGE. THIS SHORT WAVE TO DROP SOUTHEAST ACROSS SASKATCHEWAN AND MANITOBA AND REACH WESTERN ONTARIO BY WEDNESDAY MORNING. LOW LEVEL WINDS BACK TO SOUTHWEST AS THE RIDGE CONTINUES TO THE EAST AND THE LOW ASSOCIATED WITH THE SHORT WAVE MOVES JUST NORTH OF THE ONTARIO- MINNESOTA BORDER. SOUTHWEST WINDS AND AT LEAST PARTLY SUNNY SKIES SHOULD ALLOW TEMPS ON WEDNESDAY TO PUSH INTO THE LOWER AND MID 40S BEFORE THE COLD FRONT TRAILING FROM THE LOW PASSES THROUGH THE FORECAST AREA LATE WEDNESDAY AFTERNOON AND EVENING. THIS RETURNS THE REGION TO DEEP NORTHWEST FLOW AND COLD AIR ADVECTION. ANOTHER SHORT WAVE TO DROP ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES THURSDAY AND THURSDAY NIGHT WITH REINFORCING COLD AIR BUT LITTLE THREAT OF SIGNIFICANT SNOW SAVE FOR LAKE EFFECT AREAS OF LOWER MI AND NORTHERN INDIANA. WITH COLD FLOW REGIME BACK...DAYTIME TEMPS RESTRICTED TO ONLY THE 30S THURSDAY AND FRIDAY. LATEST GFS SEEMS TO BE ALONE IN DROPPING A SHORT WAVE AND ACCOMPANYING SURFACE LOW ALONG WITH A STRIPE OF ACCUMULATING SNOW INTO THE MID MISSISSIPPI VALLEY LATE FRIDAY NIGHT AND SATURDAY SO HAVE MAINTAINED DRY FORECAST FOR NOW. TRS && .AVIATION... 1800 UTC TAFS...SURFACE RIDGE ALONG A STL-RFD-GRB LINE PER 17Z ANALYSIS AND WILL CONTINUE TO SLOWLY BUILD EAST THIS AFTERNOON. PERIOD OF WINDS NEAR CALM BEING OBSERVED AS RIDGE AXIS MOVES EAST OF GROUND STATIONS FOR A FEW HOURS BEFORE SOUTHERLY FLOW IS REESTABLISHED VIA QUICKLY TIGHTENING GRADIENT TO THE WEST OVER IA. UNTIL RIDGE AXIS APPROACHES DPA-ORD-MDW AND THEN FINALLY GYY EXPECT 330-350 WINDS TO PERSIST BUT BE REMAIN RELATIVELY LIGHT AS GRADIENT CONTINUES TO SLACKEN. THE LAST VESTIGES OF LAKE EFFECT SNOW BAND PUNCHING ON SHORE IN NW INDIANA AT THIS TIME WEAKENING AS INVERSION HEIGHT LOWERS AND WIND WEAKENS AND LOW LEVEL CONVERGENCE SLACKENS. MAY SEE A SNOW SHOWER CLIP GYY UNTIL 19Z BEFORE BOUNDARY TO H850 WINDS TURN MORE WESTERLY AND PUSH ANY LINGERING WEAKENING SHOW SHOWERS AND FLURRIES BACK EASTWARD. OUTSIDE OF LAKE INDUCED SC WHICH WILL PERSIST FOR SEVERAL MORE HOURS DOWNSTREAM OF LAKE MI WITH NW FLOW...ONLY MODESTLY INCREASING CI AND AC WILL MAR AN OTHERWISE CLEAR SKY THROUGH SUNSET ACROSS NRN IL. EXPECT SCT-BKN MID AND HI CLOUDS TO BE THE RULE TONIGHT AS WEAK SHORTWAVE TROUGH MOVES THROUGH UPPER RIDGING PATTERN TRYING TO NOSE INTO THE WESTERN GREAT LAKES. ED F && .MARINE... 314 AM CST A LARGE HIGH WAS OVER MINNESOTA AND IOWA THIS MORNING. A WEAK LOW WAS OVER SOUTHWEST MICHIGAN. THIS LOW IS PART OF THE LAKE EFFECT SNOW OVER NORTHWEST INDIANA AND SOUTHWEST MICHIGAN. ANOTHER LOW WAS AT 38 NORTH LATITUDE AND 74 WEST LONGITUDE. THIS LOW...OFF THE COAST OF NEW JERSEY...AND THE HIGH ARE PROVIDING THE NORTH WIND ON LAKE MICHIGAN THIS MORNING. THE HIGH WILL MOVE SOUTHEAST TO WESTERN KENTUCKY BY THIS EVENING. A LOW WILL DEVELOP IN NORTH DAKOTA AND WILL MOVE TO EASTERN LAKE SUPERIOR BY WEDNESDAY AFTERNOON. BY THURSDAY EVENING...A LARGE HIGH WILL MOVE TO CENTRAL MANITOBA AND SPREAD SOUTH TO OKLAHOMA. WE EXPECT NO FREEZING SPRAY THIS MORNING OR TUESDAY NIGHT. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM WEDNESDAY TO 9 PM THURSDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM TUESDAY. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 1135 AM CST TUE NOV 18 2008 .DISCUSSION... 1135 AM CST WILL ALLOW LAKE EFFECT SNOW WARNINGS TO EXPIRE AS SCHEDULED AT 18Z. LAKE EFFECT MACHINE SLOWLY WINDING DOWN LATE THIS MORNING AS INVERSION HEIGHTS ARE QUICKLY LOWERING. RADAR TRENDS HAVE SHOWN A GRADUAL DE-ORGANIZATION OF THE SNOW SHOWERS WITH LESS AND LESS INLAND PENETRATION OVER THE PAST COUPLE HOURS. WHILE A BRIEF MODERATE SNOW SHOWER IS STILL POSSIBLE INTO THE EARLY AFTERNOON...FEEL FAIRLY CONFIDENT THAT ANY ADDITIONAL ACCUMULATIONS WILL BE AN INCH OR LESS GIVEN THE RECENT TRENDS IN RADAR/SATELLITE REPRESENTATION OF THE LES. UPDATED GRIDS/TEXT PRODUCTS WILL BE ISSUED BY NOON. IZZI && .PREV DISCUSSION... 430 AM CST INTENSE LAKE EFFECT SNOW BAND HAD BACKED UP INTO PORTER AND EASTERN LAKE COUNTIES OF NORTHWEST INDIANA DURING THE VERY EARLY MORNING. LATEST NAM12 AND RUC13 MODEL RUNS CONTINUE TO DEPICT THIS BAND WELL...KEEPING AXIS OVER PORTER AND EASTERN LAKE COUNTIES SOUTH ACROSS THE KANKAKEE RIVER INTO JASPER AND NORTHEASTERN NEWTON COUNTIES THROUGH MID MORNING. VERY COLD MID LEVEL AIR IN WAKE OF THE SHORT WAVE TROUGH THAT DROPPED SOUTHEAST ACROSS THE REGION LAST EVENING HAS ALLOWED CLOUD TOPS OF THE LAKE EFFECT BAND TO APPROACH 20K FT IN DEPTH PER RADAR. EXPECT MODERATE TO HEAVY LAKE EFFECT TO PERSIST IN FAR NORTHWEST INDIANA WITH LIGHTER SNOW SHOWERS AS FAR WEST AS THE ILLINOIS STATE LINE. WEB CAM ON 80/94 AT RIPLEY HAS BEEN SHOWING PERIODS OF HEAVY SNOW WITH SNOW COVERED HIGHWAY. BAND DEPICTED SHIFTING BACK TOWARD THE EASTERN SIDE OF THE LAKE BY LATE MORNING WITH BACKING OF LOW LEVEL SYNOPTIC FLOW...AND INTENSITY OF SNOWFALL FROM THE BAND WILL BE DIMINISHING AS MID LEVEL WARMING CAUSES IN A LOWERING OF THE EQUILIBRIUM LEVEL AND RESULTS IN LESS VIGOROUS CONVECTION OVER THE LAKE. THE SURFACE RIDGE CURRENTLY LOCATED OVER MINNESOTA...IOWA AND MISSOURI WILL CONTINUE TO SHIFT EASTWARD ACROSS THE MIDWEST TODAY KEEPING SKIES...OUTSIDE OF THE LAKE EFFECT AREAS...SUNNY FOR A WHILE BEFORE HIGH AND MID LEVEL CLOUDS START TO INVADE FROM THE NORTHWEST THIS AFTERNOON WITH THE MID LEVEL WARM ADVECTION IN ADVANCE OF A SHORT WAVE TOPPING THE WESTERN NORTH AMERICAN UPPER RIDGE. THIS SHORT WAVE TO DROP SOUTHEAST ACROSS SASKATCHEWAN AND MANITOBA AND REACH WESTERN ONTARIO BY WEDNESDAY MORNING. LOW LEVEL WINDS BACK TO SOUTHWEST AS THE RIDGE CONTINUES TO THE EAST AND THE LOW ASSOCIATED WITH THE SHORT WAVE MOVES JUST NORTH OF THE ONTARIO- MINNESOTA BORDER. SOUTHWEST WINDS AND AT LEAST PARTLY SUNNY SKIES SHOULD ALLOW TEMPS ON WEDNESDAY TO PUSH INTO THE LOWER AND MID 40S BEFORE THE COLD FRONT TRAILING FROM THE LOW PASSES THROUGH THE FORECAST AREA LATE WEDNESDAY AFTERNOON AND EVENING. THIS RETURNS THE REGION TO DEEP NORTHWEST FLOW AND COLD AIR ADVECTION. ANOTHER SHORT WAVE TO DROP ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES THURSDAY AND THURSDAY NIGHT WITH REINFORCING COLD AIR BUT LITTLE THREAT OF SIGNIFICANT SNOW SAVE FOR LAKE EFFECT AREAS OF LOWER MI AND NORTHERN INDIANA. WITH COLD FLOW REGIME BACK...DAYTIME TEMPS RESTRICTED TO ONLY THE 30S THURSDAY AND FRIDAY. LATEST GFS SEEMS TO BE ALONE IN DROPPING A SHORT WAVE AND ACCOMPANYING SURFACE LOW ALONG WITH A STRIPE OF ACCUMULATING SNOW INTO THE MID MISSISSIPPI VALLEY LATE FRIDAY NIGHT AND SATURDAY SO HAVE MAINTAINED DRY FORECAST FOR NOW. TRS && .AVIATION... 1200 UTC TAFS... 612 AM CST THE WIND DIRECTION FOR THE AIRPORTS IN NORTH CENTRAL...NORTHEAST ILLINOIS AND NORTHWEST INDIANA WILL BE RESULTING FROM THE MOVEMENT OF A LARGE HIGH OVER IOWA THIS MORNING. THERE WILL BE A NORTH WIND AT THE AIRPORTS THIS MORNING. THE HIGH WILL MOVE SOUTH TO WESTERN KENTUCKY BY THIS EVENING. THERE WILL BE A SOUTH WIND AFTER 22 UTC AT THE AIRPORTS. A LOW WILL MOVE INTO NORTH DAKOTA THIS MORNING. THE PRESSURE GRADIENT BETWEEN THE HIGH AND LOW WILL BE LARGE ENOUGH TO GIVE 14 TO 19 KNOT WIND LATE MORNING AND EARLY AFTERNOON. WE EXPECT VFR CLOUDS TODAY. THERE WILL BE A TEN THOUSAND FOOT CEILING BY THIS EVENING. && .MARINE... 314 AM CST A LARGE HIGH WAS OVER MINNESOTA AND IOWA THIS MORNING. A WEAK LOW WAS OVER SOUTHWEST MICHIGAN. THIS LOW IS PART OF THE LAKE EFFECT SNOW OVER NORTHWEST INDIANA AND SOUTHWEST MICHIGAN. ANOTHER LOW WAS AT 38 NORTH LATITUDE AND 74 WEST LONGITUDE. THIS LOW...OFF THE COAST OF NEW JERSEY...AND THE HIGH ARE PROVIDING THE NORTH WIND ON LAKE MICHIGAN THIS MORNING. THE HIGH WILL MOVE SOUTHEAST TO WESTERN KENTUCKY BY THIS EVENING. A LOW WILL DEVELOP IN NORTH DAKOTA AND WILL MOVE TO EASTERN LAKE SUPERIOR BY WEDNESDAY AFTERNOON. BY THURSDAY EVENING...A LARGE HIGH WILL MOVE TO CENTRAL MANITOBA AND SPREAD SOUTH TO OKLAHOMA. WE EXPECT NO FREEZING SPRAY THIS MORNING OR TUESDAY NIGHT. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...LAKE EFFECT SNOW WARNING...INZ001-INZ002 UNTIL NOON TUESDAY. LM...GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM WEDNESDAY TO 9 PM THURSDAY. SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 1 PM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 PM TUESDA && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 525 PM EST TUE NOV 18 2008 .SYNOPSIS... HIGH PRESSURE WILL BUILD FROM THE MID MISSISSIPPI RIVER VALLEY TO THE MID ATLANTIC REGION TONIGHT THROUGH WEDNESDAY. A COLD FRONT WILL PUSH THROUGH THE AREA LATE THURSDAY...FOLLOWED BY ANOTHER PERIOD OF UNSEASONABLY COLD WEATHER FRIDAY INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... STARTING TO SEE SIGNS OF BANDING DVLPG OVER THE NRN BAY AND H92 OMEGA FIELDS ON NAM/RUC GUIDANCE HAS BEEN HINTING AT THIS OVER THE PAST 24 HRS. ALREADY HAVE SEEN A DECENT BAND FORM EARLIER THIS AFTN FURTHER NORTH OVER THE DELAWARE BAY AS WINDS WERE PRIMARILY WNW FROM THE SFC TO H-70. WINDS HAVE SHIFTED MORE TO THE NNW FROM THE SFC TO H92 WHICH HAS MADE BAND MORE UNORGANIZED AND ERRATIC. AS WINDS SHIFT TO THE NORTH A QUICK BURST OF -SN SHRAS COULD MOVE INTO FAR NORTHEASTERN THIRD OF WORCESTER (INCLUDING OCEAN CITY) AS DOX RADAR SHOWS SIGNS OF ENHANCEMENT OFF THE TIP OF CAPE MAY. BEST BANDING LATER THIS EVE LOOKS TO OCCUR OVER THE NORTHERN CHES BAY AND INTO THE LOWER ERN SHORE (MAINLY OVER SRN ACCCOMACK AND NRN NORTHAMPTON). THIS WILL BE THE AREA OF CONCERN THIS EVE/EARLY TONIGHT FOR ANY POSSIBLE ACCUMS OF SNOW IF ANY BANDS CAN GET ORGANIZED OVER THE NEXT FEW HOURS. OVERNIGHT...925-800 MB LYRD AIR TRAJ ABT 340 DEGS...NAM12 RH/OMEGA FCST SUGG THAT NARROW BANDS (STREAMERS) ONGOING OVER THE SRN ERN SHORE THIS EVE/ERLY OVRNT COULD PTNTLLY CLIP PORTIONS OF THE SRN VA ERN SHR LATE TNT/ERLY TMRW...IN ADDTN TO VA BCH/NRN OTR BNKS (EVEN ORF AREA COULD SEE ENHANCED SNSH...HWVR...ATTM TRAJ FCST APRS TO BE JUST ENUF NW INSTD OF N TO KP ANY BAND JUST E OF THAT CITY). XPCTG COLD NGT OF THE SEASON SO FAR...W/ MANY LCTNS AWAY FM THE BAY/OCN HVG TEMPS FALL INTO THE 20S. TRAJ FM NNW OFF THE BAY SHOULD KP LO TEMPS FM FALLING BLO 32 DEGS ORF/VA BCH VCNTY/NRN OTR BNKS TO PRECLUDE A FRZ WRNG ATTM. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... PTRN ALOFT RELAXES A BIT WED THROUGH THU AS TROUGH ALOFT SHIFTS WELL E OF THE ERN CBRD. RMNG COLD AGN WED...BUT DRY...AS ANY WAA INDUCED PCPN RMNS SUFFICIENTLY N OF FA. HI TEMPS IN THE L/M 40S. ANOTHER COLD NGT WED NGT W/ LGT WNDS...LEADING TO TEMPS FALLING QUIKLY IN THE EVE...B4 LEVELING OFF. EVEN CSTL AREAS IN SE VA/NE NC SHOULD HV FRZG TEMPS...AND WOULD NEED WRNG (TO OFFICIALLY END GROWING SEASON). LO TEMPS IN THE 20S TO ARND 30. MODERATION OF AMS XPCTD THU W/ DP LYRD WLY FLO...ANY COOLING FM NEXT CDFNTL PASSAGE (IN THE AFTN) SHOULD HOLD OFF UNTIL EVE. XPCTG HI TEMPS IN THE L/M 50S. NEXT SHOT OF COLD AIR ARRIVES THU NGT/FRI AS NEXT AMPLIFICATION OF UPR LVL TROUGH OCCURS (FOLLOWED BY STRNG CANADIAN HI PRES RETURNING). 850 MB TEMPS ONCE AGN TO PLUNGE TO NR LVLS OF TDAS...NR -10/-11 DEGS C...WHICH COULD LEAD TO SCT FLURRIES AND/OR SNSH. WL NEED TO MONITOR FOR PSBL BAY PLUME AGN FRI AFTN/EVE INTO SE VA/CSTL NE NC. HI TEMPS IN THE L/M 40S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MDLS IN GEN AGREEMENT WITH LOW PRES STRENGTHENING OFF THE MID-ATLANTIC COAST AS STRONG HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST FRIDAY INTO SATURDAY. PRES GRAD WILL AGAIN BRING BREEZY CONDS AT LEAST FOR THE FIRST PART OF THE WEEKEND BEFORE TAPERING LATE SATURDAY INTO SUN MORNING. HIGH PRESSURE IS PROGGED TO BE ANCHORED IN FOR THE REMAINDER OF THE WEEKEND INTO TUESDAY FOR NOW. LOOKS TO BE A MOSTLY DRY PERIOD WITH HIGH TEMPS GENERALLY IN THE 40S BEFORE MODERATING SOMEWHAT INTO THE 50S BY SUNDAY. LOW TEMPS WILL LIKELY BE IN THE M/U 30S...40S ON SUNDAY. && .AVIATION /22Z TUESDAY THROUGH SUNDAY/... ONLY A FEW SNOW SHOWERS DEVELOPED OVER THE REGION OVERNIGHT AND THIS MORNING WITH MOST SHOWERS ON THE EASTERN SHORE DUE TO BAY AFFECT. WIDESPREAD COLD AIR CU DEVELOPING OVER THE AREA SO SCT/BKN CIGS 3500-6000 FT WILL AFFECT THE TERMINALS INTO THE EARLY EVENING. A FEW RAIN OR SHOW SHOWERS STILL PSBL THRU THE AFTN AND EARLY EVENING. STRONG NW-N FLOW WILL CONT THRU THE EVENING INTO WED AS COASTAL LOW MOVES NORTH AND SFC HIGH TO THE WEST SHIFTS SOUTHWARD. WIND SPDS WILL SUBSIDE ON WED TO 10-15 KT AVG. WINDS WILL GRADUALLY SHIFT TO THE SW BY LATE WED AS HIGH MOVES SOUTH AND A WEAK LOW AND FRONT APPROACHES. NO WEATHER IMPACT EXPECTED AS OF THIS TIME AND VFR CONDS THRU FRI. && .MARINE... WITH CURRENT WX SET-UP...STRONG PRES GRAD, ETC. GALES WL REMAIN UP THROUGH TOMORROW AND XPCT SCA FLAGS UP FOR MOST OF THE WEEK AND MAYBE INTO THE WEEKEND. MDLS INDICATE ANOTHER SURGE OF COLD AIR AND SUBSEQUENT GALE OR SCA POSSIBLE FRI INTO SATURDAY. LINGERING EFFECTS ARE LIKLELY TO REMAIN AT LEAST OVER THE WATERS UNTIL POSSIBLY LATE SUNDAY BEFORE FINALLY SUBSIDING AT LEAST OVER THE CHES BAY. && .CLIMATE... LAST TIME MEASURABLE SNOWFALL OCCURRED IN NOVEMBER: RICHMOND....1991/8TH (0.1") NORFOLK.....1987/11TH (0.3") SALISBURY...1989/22-23RD (2.5") RCRD LO TEMPS: NOV 19 RIC 18 1936 ORF 25 1959 SBY 17 1936 ECG 21 1959 NOV 20 RIC 21 1951 ORF 27 1980 SBY 22 1924 ECG 25 1997 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...GALE WARNING UNTIL 8 AM EST WEDNESDAY FOR ANZ630>633. GALE WARNING UNTIL 11 AM EST WEDNESDAY FOR ANZ650-652-654-656- 658. && $$ SYNOPSIS...ALB/LKB NEAR TERM...CCW SHORT TERM...ALB LONG TERM...KLL AVIATION...JEF MARINE...KLL CLIMATE... md AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE ABERDEEN SD 1106 AM CST TUE NOV 18 2008 .UPDATE... NO MAJOR UPDATES MADE TO THE FORECAST THIS MORNING. WILL HAVE TO MONITOR TEMPERATURES FOR THE NEXT COUPLE OF HOURS AS CLOUD COVER MAY HINDER WARMING A BIT THIS AFTERNOON. WILL LEAVE TEMPS AS IS FOR NOW AND RE-EVALUATE DURING THE EARLY AFTERNOON FOR POTENTIAL CHANGES. && .PREV DISCUSSION... .SHORT TERM...TODAY THROUGH THURSDAY WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW UPPER LEVEL RIDGING CENTERED OVER THE ROCKIES AND BUILDING SLOWLY EAST. AT THE SURFACE...SOUTHERLY WINDS BEGINNING TO PICK UP A BIT AS HIGH PRESSURE CONTINUES TO MOVE EAST AND AWAY FROM THE REGION. ACROSS WESTERN CWA WINDS IN THE 15 TO 20 MPH RANGE WHILE ACROSS THE EAST THEY ARE APPROACHING 10 MPH. TEMPERATURES HAVE BECOME NEARLY STEADY OR HAVE RISEN A COUPLE DEGREES IN SOME LOCATIONS AS WARMER AIR CONTINUES TO MOVE INTO THE AREA. IMPRESSIVE WAA SPREADS OVER THE AREA TODAY AS SOUTHERLY WINDS INCREASE OUT AHEAD OF APPROACHING WARM FRONT. FOR EXAMPLE...06Z NAM SHOWS 850 MB TEMPS OF AROUND -2 C ACROSS THE JAMES VALLEY AT 12Z THIS MORNING...BUT WARMS UP TO +11 C BY LATE THIS AFTERNOON. WITH SOUTHERLY WINDS INCREASING...WILL BE ABLE TO MIX WARMER AIR DOWN TO THE SURFACE. WILL THEREFORE SEE WARMER TEMPS WITH A MAJORITY OF THE AREA SEEING 40S AND 50S. ACROSS THE FAR EASTERN CWA WHERE COOLER AIR WILL BE IN PLACE THE LONGEST TODAY...MAY ONLY SEE UPPER 30S FOR HIGHS. SOUTHERLY WINDS WILL INCREASE INTO THE BREEZY CATEGORY TODAY MAINLY EAST OF THE MISSOURI RIVER WITH SPEEDS RANGING FROM 15 TO 25 MPH. WARM FRONT WILL CONTINUE TO MOVE EAST THIS EVENING...REACHING THE MISSOURI RIVER BY AROUND 00Z AND THE I-29 CORRIDOR BY 06Z. SHOULD SEE TEMPS STEADY OUT THEN SLOWLY RISE TONIGHT AS WINDS SWITCH TO A WESTERLY DIRECTION BEHIND THE WARM FRONT. THIS PLAYS OUT IN THE TEMP GRIDS ALSO. THEN FOR WEDNESDAY...CAA SPREADS ACROSS THE AREA AS COLD FRONT DROPS SOUTH THROUGH THE DAKOTAS. CONSTRUCTED GRIDS TO SHOW A LATE MORNING OR EARLY AFTERNOON HIGH TEMPERATURE THEN AS CAA BECOMES MORE SUBSTANTIAL...SHOULD SEE TEMPS STEADY OUT OR SLOWLY FALL DURING THE AFTERNOON. BIGGEST PUSH OF CAA OCCURS BETWEEN 18Z AND 00Z WEDNESDAY. ATTENTION THEN TURNS TO LATE WEDNESDAY NIGHT AND THURSDAY AS A WEAK SHORTWAVE DROPS SOUTHEAST ACROSS THE AREA. NAM/GFS TRY TO SPIT OUT .01 QPF HERE AND THERE ACROSS EASTERN SD...SUGGESTING PERHAPS FLURRIES OR VERY LIGHT SNOW SHOWERS. SREF PROBS OF .01 SHOW NOTHING. NOT A LOT OF MOISTURE TO WORK WITH BUT BUFKIT SOUNDINGS SHOW BEST MOISTURE LATE WEDNESDAY NIGHT. BUFKIT GFS SOUNDING SHOWS LIGHT SNOW AT KABR AT 12Z THURSDAY WITH NEAR SATURATION IN SNOW GROWTH REGION. DURING THE DAY THURSDAY ONLY A SHALLOW LAYER OF MOISTURE AROUND 850MB...BUT FAIRLY STEEP LAPSE RATES BELOW THIS SHALLOW LAYER. NOT MUCH IN THE WAY OF LIFT EITHER BUT THERE IS A STRONG SURFACE HIGH MOVING IN WHICH COULD HELP TO SCOUR OUT A FEW FLURRIES. HAVE DECIDED TO ADD SCT FLURRIES FOR LATE WEDNESDAY NIGHT THROUGH THURSDAY AS THIS WAVE PASSES. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY MAIN FCST CHALLENGE FOR THE EXTENDED DEALS WITH SORTING OUT MODEL SOLNS HEADING INTO THE WEEKEND. MODELS STILL REMAIN BASICALLY IN TWO CAMPS FOR THE EXTENDED FORECAST. THE GFS/UKMET/DGEX SOLN ALL POINT TOWARD STRONGER WAVE CRASHING OVER THE WRN CONUS RIDGE...CLOSED 5H/7H LOWS DROPPING INTO THE CWA FOR FRIDAY. THE EC/CANADIAN/ENSEMBLE MEMBERS AGREE WITH THIS WAVE CRASHING INTO THE RIDGE...BUT KEEP THE SYSTEM MORE OF AN OPEN WAVE AS IT TRAVERSES TO THE EAST. THE EC IS NOW TRENDED TO A BIT MORE ENERGY DROPPING SOUTH...MORE INTO ND THAN CANADA...AND THE LATEST RUN NOW PAINTS A BIT OF QPF ACROSS THE ERN DAKOTAS FOR THE DAY FRIDAY. GIVEN THAT CONFIDENCE IS LOW FOR ANY PARTICULAR SOLN...HAVE JUST KEPT WITH PERSISTENCE AND LEFT THE EXTENDED DRY FOR NOW. ALSO INTERESTING IS THAT THE EC IS NOW DROPPING THIS SYSTEM SOUTH INTO THE UPPER MIDWEST TO BEGIN NEXT WEEK...WHILE THE GFS MAINTAINS A ZONAL FLOW APPEARANCE ACROSS THE NRN TIER STATES. TEMP WISE...THE MODELS DO AGREE ON HIGH PRESSURE AT THE SFC BEING OVER THE REGION FOR THURSDAY NIGHT/FRIDAY MORNING. WITH SPEC HUMIDITIES LEANING TO MOCLEAR SKIES...THIS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING TO TAKE PLACE. HAVE LOWERED THURSDAY NIGHT LOWS BY A CATEGORY OR SO ACROSS THE CWA. OTHERWISE STUCK PRETTY CLOSE TO INHERITED MAX/MIN TEMP GRIDS DUE TO UNCERTAINTY IN THE MODELS. && .AVIATION... VFR CONDS ARE EXPECTED TO PERSIST THROUGH THE FCST PERIOD FOR ALL TERMINAL SITES. SCT-BKN080-100 CLOUDS WILL DRIFT NW TO SE ACROSS THE CWA THROUGH THE PERIOD. VSBYS WILL BE UNRESTRICTED. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...PARKIN SHORT TERM...TMT LONG TERM...HINTZ AVIATION...HINTZ WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 257 PM CST TUE NOV 18 2008 .SHORT TERM...TONIGHT AND WEDNESDAY...LATEST RUC ANALYSIS AND VIS/IR/WV/RADAR IMAGERY SHOW A 1035MB SURFACE HIGH CENTERED OVER MO/IL WHOSE RIDGE AXIS EXTENDS NE ALONG THE SPINE OF LAKE MICHIGAN INTO ONTARIO. SKIES ARE PARTLY TO MOSTLY SUNNY ACROSS THE FORECAST AREA DEPENDING ON HOW MUCH SUNSHINE IS BEING FILTERED BY VARIABLE CIRRUS THICKNESS. NEXT SHORTWAVE ROUNDING THE CREST OF THE WESTERN NOAM RIDGE IS SET TO DIVE SE WITHIN THE FAST NW FLOW ALOFT. CLOUDS THICKEN AHEAD OF THE SHORTWAVE OVER THE NORTHERN PLAINS DUE TO ISENTROPIC ASCENT ON THE 285-295K SURFACES. HAVEN`T SEEN ANY REPORTS OF PRECIP WITHIN THIS WAA REGIME...MOSTLY DUE TO THE MID/UPPER LEVEL MOISTURE BEING LOCATED TOO FAR AHEAD OF THE LOWER MOISTURE. AS THIS ASCENT AND MOISTURE SHIFT INTO WISCONSIN LATE TONIGHT INTO TOMORROW...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. HIGH PRESSURE RIDGE AXIS SHIFTS EAST THIS EVENING...BUT WINDS WILL BE STILL LIGHT ENOUGH FOR DECOUPLING AND TEMPS WILL FALL RATHER RAPIDLY DESPITE THE THIN VEIL OF CIRRUS OVERHEAD. WINDS WILL SHIFT AROUND TO THE SOUTHWEST AND BEGIN TO STRENGTHEN BY LATE EVENING AS ISENTROPIC ASCENT MOVES IN OVERNIGHT. BUT JUST LIKE OUT WEST...MID-LEVEL MOISTURE WILL CONTINUE TO OUTRUN ITS LOWER MOISTURE MORE CLOSELY TIED TO THE WARM FRONT. AS A RESULT...MOISTURE DEPTH NEVER REALLY REACHES -10C...INCREASING THE CHANCES OF FREEZING DRIZZLE...UNLESS SOME SEEDER FEEDER PROCESSES OCCUR RIGHT AS THE MID-LEVEL CLOUDS ARE EXITING. THERE IS ALSO SOME DRY AIR RIGHT ABOVE THE SURFACE...WHICH WILL LIMIT THE FREEZING DRIZZLE POTENTIAL. SO HAVE MAINTAINED THE PATCHY FREEZING DRIZZLE AND FLURRIES MENTION ACROSS THE NORTHERN THIRD OF THE FORECAST AREA WHERE MOISTURE IS THE DEEPEST. BEST CHANCES OF ANY FREEZING DRIZZLE WILL OCCUR OVER THE HIGHER TERRAIN WHERE CLOUD BASES WILL BE LOWER. LOWS WILL OCCUR BY LATE EVENING OR EARLY OVERNIGHT...AND WILL RANGE FROM THE MIDDLE TEENS NORTH TO MID 20S SE. THE SHORTWAVE PASSES OVER THE NORTHERN GREAT LAKES TOMORROW...WITH A WEAK SURFACE LOW AHEAD OF IT...PASSING OVER UPPER MICHIGAN. EVEN WITHOUT MID-LEVEL MOISTURE...DECENT LARGE-SCALE ASCENT AHEAD OF THE WAVE AND INCREASED CYCLONIC FLOW WILL IMPROVE SNOW SHOWER CHANCES DURING THE MORNING ACROSS THE NORTHERN FORECAST AREA. STILL CANNOT RULE OUT PATCHY FREEZING DRIZZLE EITHER BECAUSE OF THE LIMITED MOISTURE PROBLEM. COLD ADVECTION SETS IN DURING THE AFTERNOON AS WINDS SHIFT AROUND TO THE NW BEHIND THE SURFACE LOW. 850MB TEMPS FALL TO AROUND -10C...ENOUGH TO THINK ABOUT LAKE EFFECT SNOW POTENTIAL ONCE AGAIN. LOW LEVEL WINDS WILL BE VEERING RAPIDLY THROUGH THE AFTERNOON...AND IT WILL TAKE AWHILE FOR BANDS TO BECOME ORGANIZED. SO THIS IS MORE OF A PROBLEM FOR TOMORROW NIGHT (SEE BELOW). REGARDLESS...THE COMBINATION OF COLD ADVECTION AND STRONG SYNOPTIC WINDS WILL MEAN A CLOUDY AND WINDY DAY TOMORROW...WITH SOME LIGHT PRECIP OVER THE NORTH...AND HIGHS RANGING THROUGH THE 30S. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY MAIN FOCUS DURING THE PERIOD WILL BE THE LAKE EFFECT POTENTIAL WEDNESDAY NIGHT INTO THURSDAY NIGHT. 850MB TEMPERATURES ARE EXPECTED TO DROP TO -16 C BY THURSDAY AFTERNOON WITH PERSISTENT NORTHERLY FLOW. LOOKING AT THE BUFKIT SOUNDING OVER WESTERN LAKE SUPERIOR... WINDS LINE UP PERFECTLY THROUGH MUCH OF THE PERIOD FOR A SIGNIFICANT LAKE EFFECT SNOW EVENT FOR VILAS COUNTY. BOTH MODELS INDICATE IMPRESSIVE LAKE INDUCED CAPES OF 450 TO 600 J/KG AND EQUILIBRIUM HEIGHTS RISING TO AROUND 9500 FT. ISSUED A LAKE EFFECT SNOW WATCH FOR VILAS COUNTY FROM 6 PM WEDNESDAY NIGHT TO 6 AM FRIDAY BASED ON ALL THE AVAILABLE DATA...COORDINATING WITH DULUTH AND MARQUETTE...AND USING THE LAKE EFFECT SNOW CHART. MAIN CONCERN DURING THIS PERIOD WAS HOW TO HANDLE THE SIX HOURLY SNOW GRIDS DURING THE EVENT. THERE IS SOME QUESTION ON HOW QUICKLY THE LAKE EFFECT EVENT WILL DIMINISH THURSDAY NIGHT OR FRIDAY MORNING AS THE GFS IS QUICKER IN BACKING THE 850MB WINDS TO A MORE WESTERLY DIRECTION LATE THURSDAY NIGHT. OUTSIDE THE SNOW BELT REGION OF VILAS COUNTY...THINK THAT NORTHERN PORTIONS OF ONEIDA AND PORTIONS OF NORTHERN FOREST COUNTIES COULD SEE A COUPLE INCHES OF SNOW AS WELL DURING THE EVENT AS WELL. STRONG NORTHERLY FLOW AND AMPLE MOISTURE COMING OFF LAKE SUPERIOR COULD PRODUCE SCATTERED SNOW SHOWERS OR FLURRIES OVER THE REST OF NORTH CENTRAL AND NORTHEAST WISCONSIN THURSDAY INTO THURSDAY EVENING. MODELS CONTINUE TO DIVERGE ON HANDLING OF SYSTEM LATE THIS WEEKEND AND INTO EARLY NEXT WEEK. HAVE INCLUDED A CHANCE OF PRECIPITATION ON SUNDAY INTO MONDAY FOR THE TIME BEING AND LEFT TUESDAY DRY UNTIL THERE IS BETTER RESOLUTION OF THE MODELS. HAVE TRENDED TEMPERATURES DOWNWARD ON THURSDAY DUE TO EXPECTED CLOUD COVER AND COLD 850MB TEMPERATURES. THIS TREND CONTINUED INTO THURSDAY NIGHT AND FRIDAY AS WELL. && .AVIATION...VFR CONDITIONS WILL PREVAIL UNTIL THE OVERNIGHT HOURS WHEN A WARM FRONT APPROACHES THE WISCONSIN AREA. AS WINDS STRENGTHEN ENOUGH TO CREATE WIND SHEAR...CIGS WILL BE LOWERING WITH THE APPROACH OF THE WARM FRONT TO MVFR LEVELS OVER THE HIGHER TERRAIN TAF SITES. STILL A TOUGH CALL WHETHER THERE WILL BE ANY FZDZ OR FLURRIES...BUT APPEARS LIKE ENOUGH LIFT WILL BE PRESENT FOR A CHANCE OF SOME NUISANT PRECIP. MAIN UNCERTAINTY REVOLVES AROUND THE AMOUNT OF LOW LEVEL MOISTURE AS GUIDANCE KEEPS CIGS RATHER ELEVATED. BUT HAVE TRENDED THAT WAY USING VCSH AND WILL SEE HOW IT PLAYS OUT. MVFR CIGS AND POTENTIAL FOR LIGHT PRECIP WILL THEN CONTINUE THROUGH THE MORNING AS A WEAK SURFACE LOW PASSES JUST TO THE NORTH OF THE TAF SITES. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW WATCH FROM WEDNESDAY EVENING THROUGH LATE THURSDAY NIGHT FOR WIZ005. && $$ MPC/ECKBERG wi