Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/28/12


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
800 PM MST TUE NOV 27 2012 .UPDATE...DRY NORTHWEST FLOW ALOFT WILL PREVAIL TONIGHT WITH ONLY A FEW HIGH CLOUDS. BECAUSE OF THE DRY AIRMASS...PROTECTED LOW LYING AREAS WILL BE COOL AGAIN TONIGHT WITH LOWS IN THE 15 TO 25 DEGREE RANGE. MADE A FEW MINOR CHANGES TO TEMPERATURES...SKY AND WIND TO REFLECT CURRENT CONDITIONS. && .AVIATION...SOUTHEAST WINDS WILL TURN NORMAL DRAINAGE DIRECTION AT KDEN AND KAPA BY 06Z. AT KBJC...WINDS WILL REMAIN WEST TO SOUTHWEST. SKIES WILL REMAIN MOSTLY CLEAR WITH JUST A FEW HIGH CLOUDS. && .PREV DISCUSSION... /ISSUED 339 PM MST TUE NOV 27 2012/ SHORT TERM...RIDGE AXIS ACROSS WESTERN UTAH WITH MODERATE WEST TO NORTHWEST FLOW ALOFT OVER COLORADO. WINDS STILL A BIT GUSTY ACROSS MOUNTAINS AND FOOTHILLS THOUGH HAVE BEEN SLOWLY DECREASING DURING THE PAST FEW HOURS. STILL...A RECENT GUST OF 46 MPH NOTED ON LOVELAND PASS AROUND 12000 FEET. GUSTS WERE REACHING RED FLAG CRITERIA ACROSS PORTIONS OF THE FOOTHILLS AS WELL AS ACROSS SOUTH PARK WHERE HUMIDITY READINGS WERE AROUND 10 PERCENT. MODELS SHOW RIDGE AXIS SHIFTING EAST INTO WESTERN COLORADO DURING THE EVENING WITH GRADIENT ALOFT GRADUALLY WEAKENING. LATEST RUC CROSS SECTIONS INDICATING CROSS MOUNTAIN FLOW DECREASING TO AROUND 30 KTS AT MOUNTAIN TOP. THUS...WINDS TO GRADUALLY DECREASE AS AIRMASS COOLS AND MIXING BECOMES LIMITED. WILL LET RED FLAG WARNING EXPIRE AT 00Z AS HUMIDITY READINGS WILL BE ON THE INCREASE. OTHERWISE... SKIES TO BECOME MAINLY CLEAR DURING THE EVENING AS WAVE CLOUD ALONG URBAN CORRIDOR CONTINUES TO DISSIPATE. WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING A PORTION OF THE WAVE CLOUD TO PERSIST OVERNIGHT...BEFORE SHIFTING NORTH. BASED ON LATEST SATELLITE LOOPS...WRF IMAGERY SEEMS A BIT OVERDONE. ON WEDNESDAY...BOTH NAM AND GFS SHOW RIDGE AXIS SHIFTING ACROSS REMAINDER OF COLORADO DURING THE MORNING...WITH THE AXIS ALONG EASTERN COLORADO BORDER AT 18Z. FLOW ALOFT BECOMES MORE WESTERLY DURING THE AFTERNOON...ALLOWING THE CROSS MOUNTAIN FLOW TO INCREASE. LATEST NAM SHOWING THE COMPONENT AT MOUNTAIN TOP AROUND 45 KTS BY 00Z. THOUGH THIS MAY BE A BIT OVERDONE...BREEZY CONDITIONS TO AGAIN OCCUR ACROSS MOUNTAINS AND ALONG FOOTHILLS AS WELL AS PARK COUNTY. AIRMASS WILL AGAIN BE DRY WITH LOW HUMIDITY EAST OF THE CONTINENTAL DIVIDE. APPEARS THAT RED FLAG CONDITIONS WILL AGAIN BE MET IN SOME AREAS OF THE FOOTHILLS AND PARK COUNTY. BUT DOES NOT LOOK WIDESPREAD ENOUGH SO WILL HOLD OFF ON ISSUING A WARNING. TEMPERATURE AND THICKNESS PROGS AS WELL AS GUIDANCE INDICATING HIGHS IN THE LOWER TO MIDDLE 60S ACROSS THE PLAINS. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE AND SEEMS REASONABLE. LONG TERM...MODELS HAVE A WEAK UPPER TROUGH MOVE ACROSS THE CWA LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING. THURSDAY`S NORTHWESTERLY FLOW ALOFT IS SHORT LIVED. IT BECOMES ZONAL AND STAYS THAT WAY INTO THE EXTENDED PERIODS. SPEEDS ARE MODERATE ..MAINLY 50 TO 75 KNOTS THURSDAY THROUGH FRIDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS CONTINUE TO SHOW BENIGN SYNOPTIC SCALE ENERGY WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. THE LOW LEVEL PRESSURE AND WIND FIELDS HAVE A BRIEF SHOT OF DOWNSLOPING WITH THE UPPER TROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THEN THE GRADIENT POINTS TO NORMAL DUIRNAL WIND PATTERNS WITH A BIT OF DOWNSLOPING MIXED IN THROUGH FRIDAY NIGHT. FOR MOISTURE...THERE IS SOME...MAINLY IN THE MID AND UPPER LEVELS FROM LATE WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. THE NAM`S MOISTURE IS A BIT BETTER THAN THE GFS` IN THE MOUNTAINS...ESPECIALLY THURSDAY MORNING. MODELS HAVE NO MEASURABLE PRECIPITATION PROGGED ON THE QPF FIELDS WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NO POPS. FOR TEMPERATURES... THURSDAY AND FRIDAY`S HIGHS LOOK CLOSE TO WEDNESDAY`S. FOR THE LATER DAYS...SATURDAY THROUGH TUESDAY...MODELS HAVE ZONAL FLOW FOR THE CWA SATURDAY AND SUNDAY...THEN SOUTHWESTERLY FLOW ALOFT SUNDAY NIGHT AND MONDAY. AN UPPER TROUGH MOVES ACROSS LATE MONDAY...THEN STRONG NORTHWESTERLY FLOW ALOFT MONDAY NIGHT AND TUESDAY. THE TROUGH LOOKS A BIT STRONGER TODAY THAN YESTERDAY. BUT MOISTURE IS NOT GREAT ON ANY OF THE MODELS. A COLD FRONT MOVES IN MONDAY WITH THE TROUGH...AND BOTH MONDAY AND TUESDAY`S TEMPERATURES LOOK CLOSER TO SEASONAL NORMALS...THAN THE WARM SATURDAY AND SUNDAY HIGHS DO. WILL GO WITH MINOR ALPINE POPS LATE SUNDAY NIGHT AND MONDAY...NOTHING FOR THE PLAINS ALL FOUR DAYS. AVIATION...DOWNSLOPE WINDS BEGINNING TO WEAKEN ACROSS AREA WITH DIA SHOWING MORE OF A SOUTHEAST COMPONENT. WINDS STILL A BIT GUSTY AT BJC. WINDS TO CONTINUE TO WEAKEN DURING THE EVENING WITH DRAINAGE PATTERN DEVELOPING BY 03Z. BJC MAY STILL HAVE MORE OF A WESTERLY COMPONENT OVERNIGHT. ON WEDNESDAY...WEAK SOUTHERLY GRADIENT EXPECTED ACROSS AREA WITH SOUTHERLY WINDS PREVAILING. POTENTIAL FOR A WEAK ANTICYCLONE DEVELOPING IN THE DENVER AREA DURING THE AFTERNOON WINDS MORE OF A SOUTHEAST DIRECTION AT DEN. SPEEDS AROUND 8 KTS TO PREVAIL...THOUGH SOME GUSTS TO 20 KTS POSSIBLE AT BJC DURING THE AFTERNOON WITH DOWNSLOPE FLOW. VFR TO CONTINUE. FIRE WEATHER....RED FLAG WARNING TO CONTINUE UNTIL 5 PM MST TODAY FOR FOOTHILLS AND PARK COUNTY. WINDS STILL GUSTING IN THE 25-30 MPH IN SOME LOCATIONS WITH LOW HUMIDITY. WINDS TO GRADUALLY DECREASE DURING THE EVENING WITH A SLOW INCREASE IN HUMIDITY. ON WEDNESDAY...AIRMASS TO REMAIN DRY. BREEZY CONDITIONS AGAIN EXPECTED ACROSS PORTIONS OF FOOTHILLS AND PARK COUNTY DURING THE AFTERNOON. DOES NOT LOOK WIDESPREAD TO WARRANT A RED FLAG WARNING. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RJK UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
313 PM MST MON NOV 26 2012 .SHORT TERM...WEAK SURFACE HIGH SLIDING ACROSS CENTRAL PLAINS BEHIND THIS MORNING`S COLD FRONT. LOW CLOUDS ACROSS PLAINS STILL FAIRLY EXTENSIVE BUT BEGINNING TO DISSIPATE EAST OF DENVER. STILL SOME FOG PERSISTING IN THE FOOTHILLS WEST OF DENVER...ALSO SHOWING SIGNS OF DISSIPATING. LATEST RUC CONTINUES TO SHOW A SLOW DISSIPATION OF THE LOW CLOUDS DURING THE EVENING WITH MAINLY CLEAR SKIES BY MIDNIGHT. THIS LOOKING REASONABLE AS DRIER AIR MOVES INTO REGION FROM THE WEST. THERE WILL BE SOME INCREASE IN HIGH LEVEL MOISTURE OVERNIGHT WITH WRF SYNTHETIC SATELLITE IMAGERY SUGGESTING THE DEVELOPMENT OF A WAVE CLOUD TOWARDS MORNING. WINDS TO INCREASE AGAIN ACROSS MOUNTAINS AND HIGHER FOOTHILLS AFTER MIDNIGHT AS NORTHWEST FLOW ALOFT INCREASES. MODELS SHOW CROSS MOUNTAIN FLOW AROUND 40 KTS AT MOUNTAIN TOP AT MIDNIGHT. SOME GUSTS AROUND 50 MPH POSSIBLE OVERNIGHT ACROSS THE WIND PRONE AREAS AND EXPOSED SLOPES. OVERNIGHT TEMPERATURES TO BE WARMER NEAR THE FOOTHILLS WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. ON TUESDAY...MODERATE WEST NORTHWEST ALOFT TO PREVAIL AS UPPER RIDGE BUILDS INTO AREA. GUSTY WINDS WILL CONTINUE ACROSS THE MOUNTAINS AND FOOTHILLS...EXTENDING INTO THE WESTERN SECTIONS OF THE URBAN CORRIDOR DURING THE MORNING. SOME GUSTS TO 50 MPH WILL BE POSSIBLE OVER THE HIGHER EXPOSED AREAS. BY 18Z GRADIENT ACROSS THE PLAINS AND LOWER FOOTHILLS EXPECTED TO WEAKEN...THUS SHOULD SEE WINDS DECREASE AS A RESULT. HOWEVER...BREEZY CONDITIONS WILL PERSIST ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. MODELS HINT AT WAVE CLOUD ALONG FOOTHILLS DECREASING DURING THE MORNING...WITH MAINLY CLEAR SKIES PREVAILING BY AFTERNOON ACROSS THE REGION. AIRMASS ACROSS PLAINS TO BE MUCH WARMER THAN TODAY WITH HIGHS WARMING INTO THE MID 50S TO MID 60S. ALSO A SLIGHT WARMUP EXPECTED FOR MOUNTAINS WITH HIGHS IN THE 40S. .LONG TERM...MODELS HAVE AN UPPER RIDGE MOVING INTO AND OVER THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY. FOR THE MOST PART ...ZONAL FLOW WILL COVER THE CWA INTO THURSDAY MORNING. A WEAK UPPER TROUGH IS PROGGED TO MOVE THROUGH LATER THURSDAY MORNING ...WITH INCREASING NORTHWESTERLY FLOW ALOFT THE REST OF THURSDAY AND THURSDAY NIGHT. THE QG VERTICAL VELOCITY FIELDS SHOW BENIGN SYNOPTIC SCALE ENERGY OVER THE CWA TUESDAY NIGHT THROUGH THURSDAY NIGHT. NORMAL DUIRNAL WIND PATTERNS ARE EXPECTED TUESDAY NIGHT ...WITH DOWNSLOPE WEDNESDAY AND WEDNESDAY NIGHT. A FAIRLY WEAK GRADIENT IS PROGGED THURSDAY AND THURSDAY NIGHT...SO NORMAL PATTERNS ARE LIKELY. FOR MOISTURE...THERE IS VERY LITTLE TUESDAY NIGHT AND WEDNESDAY. BY WEDNESDAY NIGHT SOME MID AN UPPER LEVEL MOISTURE IS PROGGED TO MOVE IN. THE NAM HAS SOME FAIRLY DEEP MOISTURE OVER THE MOUNTAINS THURSDAY MORNING AT 12Z...THE GFS HAS LESS...THE ECMWF WAY LESS. FOR THE REST OF THURSDAY AND THURSDAY NIGHT...THERE IS A BIT OF UPPER LEVEL MOISTURE PROGGED. THE QPF FIELDS HAVE NO MEASURABLE PRECIPITATION NOTED THROUGH THE FIVE PERIODS...WITH THE EXCEPTION OF A TINY BIT OVER THE FAR NORTHWEST CWA THURSDAY MORNING AT 12Z ON THE NAM. WILL LEAVE POPS OUT FOR ALL AREAS FOR NOW. FOR TEMPERATURES...WEDENSDAY`S HIGHS LOOK 1-2 C WARMER THAN TUESDAY`S. THURSDAY`S HIGHS ARE 0-2 C COOLER THAN WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...MODELS HAVE WEST-SOUTHWESTERLY FLOW ALOFT...WITH VERY LIMITED MOISTURE. TEMPERATURES LOOK TO STAY ABOVE SEASONAL NORMALS. && .AVIATION...LOW CLOUDS SLOWLY ERODING ACROSS AREA...WITH MVFR CEILINGS PERSISTING AT BJC AND APA. CLOUDS TO CONTINUE TO ERODE THROUGH THE EVENING WITH IMPROVING CEILINGS. SHOULD EXPECT VFR CONDITIONS AT BJC AND APA BY 02Z. VFR CEILINGS TO PREVAIL AT DEN WITH CEILINGS AROUND 7000 FEET AGL BY 02Z. SKIES TO CLEAR ACROSS THE AREA AROUND 06Z WITH A GRADUAL INCREASE IN HIGH LEVEL MOISTURE OVERNIGHT. POTENTIAL FOR MOUNTAIN WAVE CLOUD DEVELOPING ALONG FOOTHILLS BETWEEN 08Z AND 15Z...SHOULD NOT HAVE MUCH IMPACT ON AREA AIRPORTS. LIGHT SOUTHEASTERLY WINDS THIS EVENING WITH DRAINAGE FLOW DEVELOPING BY MIDNIGHT. SPEEDS AROUND 10 KTS EXPECTED OVERNIGHT...THOUGH GUSTS UP TO 20 KTS POSSIBLE AT BJC. WINDS TO DECREASE AND BECOME NORTHWEST ACROSS THE AREA BY 18Z. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RJK AVIATION...D-L
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1022 AM MST MON NOV 26 2012 .UPDATE... ISSUED AT 1015 AM MST MON NOV 26 2012 CLOUDS HAVE DIMINISHED OVER THE PARK RANGE IN NW COLORADO. SUNNY AND MILD CONDITIONS WILL PREVAIL FOR TODAY AND INTO MID DECEMBER IF THE LATEST LONG TERM GFS IS TO BE BELIEVED. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 326 AM MST MON NOV 26 2012 HIGH CLOUDINESS ACROSS SE UT/SW CO EARLY THIS MORNING AND ASSOCIATED WITH THE REMAINS OF A SHEARED SHORTWAVE WILL CONTINUE TO THIN AND SHOULD BE SOUTH OF OUR AREA BY ABOUT SUNRISE. SATELLITE REVEALED LOW CLOUDS CREEPING SOUTHWARD THROUGH SOUTH-CENTRAL WY IN COLD ADVECTION AND WEAK UPSLOPE. THE NAM12...AND RUC13 TO SOME EXTENT... SHOW THIS COLD ADVECTION PUSHING INTO EXTREME NW CO BEFORE FADING AFTER MID-MORNING AS A SHORTWAVE CURRENTLY NEAR YELLOWSTONE MOVES ACROSS NE WY AND INTO THE PLAINS BY AFTERNOON. LOW CLOUDS HAVE RETURNED TO MT WERNER /K3MW/ ABOVE STEAMBOAT AS OF 10Z...THOUGH ANY PRECIP OVER THE ELKHEADS/PARK RANGES FROM THESE CLOUDS EARLY THIS MORNING WILL BE NEGLIGIBLE. HAVE ADDED SOME CLOUDINESS TO THE SKY GRIDS FOR THE NORTHERN CO MTNS TO ACCOUNT FOR THIS...AND TO A LESSER EXTENT ALONG THE NORTH SLOPE OF THE EASTERN UINTA MTNS AS THE SHALLOW NORTHERLY FLOW ARRIVES. HOWEVER...WITH DRYING WESTERLY FLOW ALOFT AT 700 MB IN THE MODELS...DO NOT EXPECT THESE CLOUDS TO LAST MUCH PAST MID-MORNING. SUNNY SKIES ARE EXPECTED ACROSS THE ENTIRE FORECAST AREA THIS AFTERNOON. TEMPS WILL BE A BIT COOLER THAN YESTERDAY ESPECIALLY ACROSS THE NORTH. AN UPPER RIDGE PUMPING UP ALONG THE WEST THIS MORNING PUSHES INLAND TONIGHT AND REACHES UT/WESTERN CO ON TUE FOR SUNNY AND STABLE CONDITIONS TOMORROW AS TEMPS BEGIN TO REBOUND. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 AM MST MON NOV 26 2012 WARM RIDGE OVER THE INTERMOUNTAIN WEST DOMINATES TUESDAY NIGHT AND WEDNESDAY...BUT BEGINS TO TAKE PUNCHES AS EARLY AS WEDNESDAY NIGHT. DEEP POLAR VORTEX WILL BE COVERING A SOLID CHUNK OF THE EASTERN PACIFIC WITH POTENT SHORT WAVES SLAMMING INTO THE WEST COAST...THIS DOES NOT DO TOO MUCH FOR THE CENTRAL ROCKIES AS SHORT WAVE ENERGY WILL BE ROTATING TOWARD THE NORTHERN ROCKIES. BUT EACH PASSING SHORT WAVE WILL BE FLATTENING THE LONG WAVE RIDGE. THE FIRST SHORT WAVE (OR VORTICITY LOBE ROTATING AROUND POLAR VORTEX) CROSSES THE FORECAST AREA WEDNESDAY NIGHT. DYNAMICAL FORCING IS OVER THE NORTHERN ROCKIES...BUT THERE IS SOME MOISTURE ADVECTION AND POTENTIAL VORTICITY THAT QUICKLY SWEEPS ACROSS WESTERN COLORADO. THE SREF AND NAM12 SHOWS SPOTTY LIGHT QPF OVER THE MOUNTAIN TOPS...BUT GFS AND ECMWF KEEP THINGS DRY. ALTHOUGH CONFIDENCE IS LOW...WILL HEDGE OUR BETS AND EXPECT SOME FLURRIES OVER THE HIGH COUNTRY WITH THIS PASSING SHORT WAVE. THE NEXT CHANCE FOR ANY MOUNTAIN SNOW WILL BE FRIDAY NIGHT...AT LEAST THE ECMWF SHOWS BETTER STRUCTURE WITH PROGRESSIVE SHORT WAVE WITH THE TAIL END BRUSHING THE NORTHERN MOUNTAINS. THE GFS SHOWS THE MOISTURE PLUME AIMED AT THE NORTHERN ROCKIES AND NW WYOMING...MISSING WESTERN COLORADO COMPLETELY. BOTH SOLUTIONS ARE PLAUSIBLE AND THE CONSENSUS MODEL BLEND ADVERTISES LOW POPS...A REASONABLE COMPROMISE FOR RIGHT NOW. SATURDAY AND SUNDAY...SUBSTANTIAL MOISTURE WITH THE PACIFIC WAVE TRAIN POINTED AT THE NORTHERN INTERMOUNTAIN REGION. THE NORTHERN PART OF THE FORECAST AREA IS ON THE EXTREME SOUTHERN FRINGE OF THIS ACTIVITY AND MOST LIKELY THERE IS NOT SUFFICIENT DYNAMICAL FORCING FOR MUCH IF ANY PRECIPITATION. BUT EXPECT A FEW CLOUDS ACROSS THE NORTH...AND GRADIENT FLOW WILL BE STRONG ENOUGH FOR SOME AFTERNOON BREEZES ACROSS THE NORTH. THE SYNOPTIC PATTERN SCREAMS MILD WEATHER THIS WEEKEND...SO MUCH SO THAT THE GFSX MOS GUIDANCE SHOW NEAR RECORD HIGH TEMPERATURES ON SUNDAY. HOW WARM?...HOW ABOUT LOWER 50S ACROSS THE UPPER YAMPA AND UPPER GUNNISON RIVER VALLEYS OR LOWER 60S IN THE DESERT VALLEYS OF SOUTHEASTERN UTAH. WHEN DOES DECEMBER ARRIVE? && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING) ISSUED AT 1015 AM MST MON NOV 26 2012 VFR CONDITIONS DOMINATE FOR THE NEW WEEK. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...JOE SHORT TERM...JAD LONG TERM...PF AVIATION...JOE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
956 AM MST MON NOV 26 2012 .UPDATE...SHALLOW LAYER OF MOIST AIR CURRENTLY ACROSS PLAINS IN WAKE OF FRONTAL PASSAGE. BASED ON WEB CAMS AND SURFACE OBS... PRECIP AND FOG SEEMS LIMITED TO AREAS IN AND NEAR FOOTHILLS AS WELL AS PORTIONS OF PALMER DIVIDE. THERE WERE SOME REPORTS OF FREEZING DRIZZLE IN DENVER AREA EARLIER THIS MORNING...BUT NOW LOOKING LIKE AREAS OF DRIZZLE AND PERHAPS SOME LIGHT SNOW. LATEST RUC INDICATING LITTLE CHANGE THROUGH EARLY AFTERNOON AND STILL LOOIS REASONABLE. ALREADY UPDATED FOOTHILLS TO KEEP FOG GOING THROUGH THE MORNING. LEFT REST OF FORECAST AS IS FOR NOW...BUT MAY MAKE SOME CHANGES AS NEEDED FOR THE NOON UPDATE. && .AVIATION...LOW CLOUDS IN PLACE BEHIND EXITING COLD FRONT. SEEMS MOST OF THE FOG OVER WESTERN DENVER INTO THE FOOTHILLS AS WELL AS ACROSS THE PALMER DIVIDE. LATEST RUC STILL SHOWING THE CLEARING DELAYED UNTIL LATER THIS AFTERNOON...ESPECIALLY AT BJC. OVERALL WILL CONTINUE WITH THE CURRENT TAF TRENDS FOR THE 18Z ISSUANCE... BUT MAY NEED TO DELAY THE CLEARING AT BJC A FEW HOURS. STILL THE POSSIBILITY OF A FEW FLURRIES THIS MORNING AND PERHAPS EARLY AFTERNOON. BUT THE MOIST AIRMASS IS FAIRLY SHALLOW SO NO ACCUMULATION IS EXPECTED IF THE FLURRIES DO OCCUR. && .PREV DISCUSSION... /ISSUED 327 AM MST MON NOV 26 2012/ SHORT TERM...THE UPPER LEVEL TROF WILL MOVE SKIRT ACROSS NORTHERN COLORADO TODAY BUT THE BRUNT OF THE PRECIP WILL BE FURTHER NORTH INTO WYOMING AND NEBRASKA. THE SURFACE COLD FRONT AS MOVED THROUGH MUCH OF THE NORTHEAST PLAINS AND THE STRATUS AND FOG DECK IS JUST BEGINNING TO SPREAD SOUTHWEST ACROSS THE FAR NORTHEAST PLAINS. ANOTHER PATCH OF STRATUS HAS JUST MATERIALIZED FROM BOULDER TO DENVER AND THIS WILL ALSO EXPAND OVER THE FRONT RANGE BEFORE DAYBREAK. OVERALL THIS MOISTURE IS VERY SHALLOW AND DON`T EXPECT MORE THAN JUST A FEW FLURRIES. WE CURRENTLY HAVE FREEZING DRIZZLE IN THE FORECAST BUT THINK THE MOIST IS LAYER IS EVEN TOO SHALLOW FOR THAT. MAY BE A BIT OPTIMISTIC ON THE DISSIPATION OF THE STRATUS TODAY AS LATEST RUC KEEPS CLOUDS IN THROUGH EARLY AFTERNOON. OVERALL...HAVE LOWER HIGH TEMPS ON THE PLAINS INTO THE 30S AND KEPT CLOUD COVER IN A BIT LONGER. BEST CHANCE OF LIGHT SNOW WILL TOWARDS THE WYOMING AND NEBRASKA BORDERS AND THAT IS WHERE THE HIGHEST POPS WILL BE. CLEARING SKIES BY TONIGHT BUT LOOKS LIKE THE WIND WILL INCREASE AGAIN OVER THE MOUNTAINS AND EAST SLOPES. POSSIBLY SOME HIGHER GUSTS UP TO 50 MPH LATE TONIGHT OVER WIND PRONE AND EXPOSED SLOPES. WILL KEEP WARMER OVERNIGHT LOWS NEAR THE HILLS WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. LONG TERM...EXPECT AN EXTENDED PERIOD OF DRY AND WARMER THAN NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD AS LOW AMPLITUDE RIDGES AND ZONAL FLOW DOMINATE. THE HIGHER MOUNTAINS WILL GENERALLY BE BREEZY IN THIS PATTERN AS WELL. TUESDAYS AND WEDNESDAYS HIGHS WILL BE BACK UP INTO THE MID 50S AND 60S FOR THE PLAINS AND IN THE 40S FOR THE MOUNTAINS WITH CLEAR SKIES. WINDS WILL BE A BIT GUSTY COMING OUT OF THE MOUNTAINS AND FOOTHILLS INTO THE WESTERN URBAN CORRIDOR TUESDAY MORNING...THEN SHOULD SETTLE DOWN OVER THE LOWER FOOTHILLS AND PLAINS THROUGH WEDNESDAY. THE HIGHER MOUNTAINS WILL CONTINUE TO HAVE BREEZY CONDITIONS. A VERY WEAK SHORTWAVE TROUGH WILL MOVE EAST OVER THE STATE THURSDAY. MODELS HAVE TRENDED DOWN WITH THE STRENGTH OF THIS FEATURE OVER THE LAST SEVERAL RUNS...ENOUGH THAT I LOWERED POPS TO JUST A FEW AREAS OF A SLIGHT CHANCE IN THE NORTHERN MOUNTAINS. THESE POPS MAY BE ABLE TO BE COMPLETELY TAKEN OUT DEPENDING ON THE NEXT RUN OR TWO. THE SHORTWAVE IS EXPECTED TO SEND A WEAK COOL FRONT OVER NORTHEASTERN COLORADO HOWEVER...WITH THE ONLY EFFECT BEING TO COOL TEMPERATURES A COUPLE DEGREES AT MOST. FRIDAY AND SATURDAY WILL FEATURE A LOW AMPLITUDE RIDGE WITH A POSSIBLE WEAK SHORTWAVE TO BRING A SLIGHT CHANCE OF SNOW TO THE NORTHERN MOUNTAINS WITH DRY AND WARM CONDITIONS REMAINING OVER THE LOWER ELEVATIONS. ON SUNDAY...MODELS ARE SHOWING A DEEPER TROUGH MOVING IN OVER THE WEST COAST. DO NOT HAVE CONFIDENCE IN THIS FEATURE THAT FAR OUT...WILL CONTINUE THE DRY AND WARM FORECAST. AVIATION...LOW CLOUDS HAVE QUICKLY DEVELOPED FROM LMO...BJC TO DEN AND SPREADING EAST AND SOUTH AND SHOULD BE INTO APA AROUND 11Z. WILL LIKELY BE MORE PESSIMISTIC ABOUT THE CLEARING A FEW HOURS TODAY AND REFLECT THIS IN NEXT 12Z TAF ISSUANCE. THERE MAY BE A FEW FLURRIES THIS AM BUT THE MOIST AIRMASS IS SO SHALLOW DOUBT THERE WILL BE ANY ACCUMULATION. SURFACE WINDS WILL BE FROM THE NORTH AND NORTHEAST THIS AM THEN SHIFTING EAST AND SOUTHEAST THIS AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....KRIEDERMAN AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
327 AM MST MON NOV 26 2012 .SHORT TERM...THE UPPER LEVEL TROF WILL MOVE SKIRT ACROSS NORTHERN COLORADO TODAY BUT THE BRUNT OF THE PRECIP WILL BE FURTHER NORTH INTO WYOMING AND NEBRASKA. THE SURFACE COLD FRONT AS MOVED THROUGH MUCH OF THE NORTHEAST PLAINS AND THE STRATUS AND FOG DECK IS JUST BEGINNING TO SPREAD SOUTHWEST ACROSS THE FAR NORTHEAST PLAINS. ANOTHER PATCH OF STRATUS HAS JUST MATERIALIZED FROM BOULDER TO DENVER AND THIS WILL ALSO EXPAND OVER THE FRONT RANGE BEFORE DAYBREAK. OVERALL THIS MOISTURE IS VERY SHALLOW AND DON`T EXPECT MORE THAN JUST A FEW FLURRIES. WE CURRENTLY HAVE FREEZING DRIZZLE IN THE FORECAST BUT THINK THE MOIST IS LAYER IS EVEN TOO SHALLOW FOR THAT. MAY BE A BIT OPTIMISTIC ON THE DISSIPATION OF THE STRATUS TODAY AS LATEST RUC KEEPS CLOUDS IN THROUGH EARLY AFTERNOON. OVERALL...HAVE LOWER HIGH TEMPS ON THE PLAINS INTO THE 30S AND KEPT CLOUD COVER IN A BIT LONGER. BEST CHANCE OF LIGHT SNOW WILL TOWARDS THE WYOMING AND NEBRASKA BORDERS AND THAT IS WHERE THE HIGHEST POPS WILL BE. CLEARING SKIES BY TONIGHT BUT LOOKS LIKE THE WIND WILL INCREASE AGAIN OVER THE MOUNTAINS AND EAST SLOPES. POSSIBLY SOME HIGHER GUSTS UP TO 50 MPH LATE TONIGHT OVER WIND PRONE AND EXPOSED SLOPES. WILL KEEP WARMER OVERNIGHT LOWS NEAR THE HILLS WITH COLDER TEMPERATURES IN LOW LYING AREAS OF THE PLAINS. .LONG TERM...EXPECT AN EXTENDED PERIOD OF DRY AND WARMER THAN NORMAL TEMPERATURES THROUGH THE LONG TERM PERIOD AS LOW AMPLITUDE RIDGES AND ZONAL FLOW DOMINATE. THE HIGHER MOUNTAINS WILL GENERALLY BE BREEZY IN THIS PATTERN AS WELL. TUESDAYS AND WEDNESDAYS HIGHS WILL BE BACK UP INTO THE MID 50S AND 60S FOR THE PLAINS AND IN THE 40S FOR THE MOUNTAINS WITH CLEAR SKIES. WINDS WILL BE A BIT GUSTY COMING OUT OF THE MOUNTAINS AND FOOTHILLS INTO THE WESTERN URBAN CORRIDOR TUESDAY MORNING...THEN SHOULD SETTLE DOWN OVER THE LOWER FOOTHILLS AND PLAINS THROUGH WEDNESDAY. THE HIGHER MOUNTAINS WILL CONTINUE TO HAVE BREEZY CONDITIONS. A VERY WEAK SHORTWAVE TROUGH WILL MOVE EAST OVER THE STATE THURSDAY. MODELS HAVE TRENDED DOWN WITH THE STRENGTH OF THIS FEATURE OVER THE LAST SEVERAL RUNS...ENOUGH THAT I LOWERED POPS TO JUST A FEW AREAS OF A SLIGHT CHANCE IN THE NORTHERN MOUNTAINS. THESE POPS MAY BE ABLE TO BE COMPLETELY TAKEN OUT DEPENDING ON THE NEXT RUN OR TWO. THE SHORTWAVE IS EXPECTED TO SEND A WEAK COOL FRONT OVER NORTHEASTERN COLORADO HOWEVER...WITH THE ONLY EFFECT BEING TO COOL TEMPERATURES A COUPLE DEGREES AT MOST. FRIDAY AND SATURDAY WILL FEATURE A LOW AMPLITUDE RIDGE WITH A POSSIBLE WEAK SHORTWAVE TO BRING A SLIGHT CHANCE OF SNOW TO THE NORTHERN MOUNTAINS WITH DRY AND WARM CONDITIONS REMAINING OVER THE LOWER ELEVATIONS. ON SUNDAY...MODELS ARE SHOWING A DEEPER TROUGH MOVING IN OVER THE WEST COAST. DO NOT HAVE CONFIDENCE IN THIS FEATURE THAT FAR OUT...WILL CONTINUE THE DRY AND WARM FORECAST. && .AVIATION...LOW CLOUDS HAVE QUICKLY DEVELOPED FROM LMO...BJC TO DEN AND SPREADING EAST AND SOUTH AND SHOULD BE INTO APA AROUND 11Z. WILL LIKELY BE MORE PESSIMISTIC ABOUT THE CLEARING A FEW HOURS TODAY AND REFLECT THIS IN NEXT 12Z TAF ISSUANCE. THERE MAY BE A FEW FLURRIES THIS AM BUT THE MOIST AIRMASS IS SO SHALLOW DOUBT THERE WILL BE ANY ACCUMULATION. SURFACE WINDS WILL BE FROM THE NORTH AND NORTHEAST THIS AM THEN SHIFTING EAST AND SOUTHEAST THIS AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....KRIEDERMAN AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
326 AM MST MON NOV 26 2012 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 326 AM MST MON NOV 26 2012 HIGH CLOUDINESS ACROSS SE UT/SW CO EARLY THIS MORNING AND ASSOCIATED WITH THE REMAINS OF A SHEARED SHORTWAVE WILL CONTINUE TO THIN AND SHOULD BE SOUTH OF OUR AREA BY ABOUT SUNRISE. SATELLITE REVEALED LOW CLOUDS CREEPING SOUTHWARD THROUGH SOUTH-CENTRAL WY IN COLD ADVECTION AND WEAK UPSLOPE. THE NAM12...AND RUC13 TO SOME EXTENT... SHOW THIS COLD ADVECTION PUSHING INTO EXTREME NW CO BEFORE FADING AFTER MID-MORNING AS A SHORTWAVE CURRENTLY NEAR YELLOWSTONE MOVES ACROSS NE WY AND INTO THE PLAINS BY AFTERNOON. LOW CLOUDS HAVE RETURNED TO MT WERNER /K3MW/ ABOVE STEAMBOAT AS OF 10Z...THOUGH ANY PRECIP OVER THE ELKHEADS/PARK RANGES FROM THESE CLOUDS EARLY THIS MORNING WILL BE NEGLIGIBLE. HAVE ADDED SOME CLOUDINESS TO THE SKY GRIDS FOR THE NRN CO MTNS TO ACCOUNT FOR THIS...AND TO A LESSER EXTENT ALONG THE NORTH SLOPE OF THE ERN UINTA MTNS AS THE SHALLOW NORTHERLY FLOW ARRIVES. HOWEVER...WITH DRYING WESTERLY FLOW ALOFT AT 700 MB IN THE MODELS...DO NOT EXPECT THESE CLOUDS TO LAST MUCH PAST MID-MORNING. SUNNY SKIES ARE EXPECTED ACROSS THE ENTIRE FORECAST AREA THIS AFTERNOON. TEMPS WILL BE A BIT COOLER THAN YESTERDAY ESPECIALLY ACROSS THE NORTH. AN UPPER RIDGE PUMPING UP ALONG THE WEST THIS MORNING PUSHES INLAND TONIGHT AND REACHES UT/WRN CO ON TUE FOR SUNNY AND STABLE CONDITIONS TOMORROW AS TEMPS BEGIN TO REBOUND. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 326 AM MST MON NOV 26 2012 WARM RIDGE OVER THE INTERMOUNTAIN WEST DOMINATES TUESDAY NIGHT AND WEDNESDAY...BUT BEGINS TO TAKE PUNCHES AS EARLY AS WEDNESDAY NIGHT. DEEP POLAR VORTEX WILL BE COVERING A SOLID CHUNCK OF THE ERN PACIFIC WITH POTENT SHORT WAVES SLAMMING INTO THE WEST COAST...THIS DOES NOT DO TOO MUCH FOR THE CENTRAL ROCKIES AS SHORT WAVE ENERGY WILL BE ROTATING TOWARD THE NRN ROCKIES. BUT EACH PASSING SHORT WAVE WILL BE FLATTENING THE LONG WAVE RIDGE. THE FIRST SHORT WAVE (OR VORTICITY LOBE ROTATING AROUND POLAR VORTEX) CROSSES THE FORECAST AREA WEDNESDAY NIGHT. DYNAMICAL FORCING IS OVER THE NRN ROCKIES...BUT THERE IS SOME MOISTURE ADVECTION AND POTENTIAL VORTICITY THAT QUICKLY SWEEPS ACROSS WRN COLORADO. THE SREF AND NAM12 SHOWS SPOTTY LIGHT QPF OVER THE MOUNTAIN TOPS...BUT GFS AND ECMWF KEEP THINGS DRY. ALTHOUGH CONFIDENCE IS LOW...WILL HEDGE OUR BETS AND EXPECT SOME FLURRIES OVER THE HIGH COUNTRY WITH THIS PASSING SHORT WAVE. THE NEXT CHANCE FOR ANY MOUNTAIN SNOW WILL BE FRIDAY NIGHT...AT LEAST THE ECMWF SHOWS BETTER STRUCTURE WITH PROGRESSIVE SHORT WAVE WITH THE TAIL END BRUSHING THE NRN MOUNTAINS. THE GFS SHOWS THE MOISTURE PLUME AIMED AT THE NRN ROCKIES AND NW WYOMING...MISSING WRN COLORADO COMPLETELY. BOTH SOLUTIONS ARE PLAUSIBLE AND THE CONSENSUS MODEL BLEND ADVERTISES LOW POPS...A REASONABLE COMPROMISE FOR RIGHT NOW. SATURDAY AND SUNDAY...SUBSTANTIAL MOISTURE WITH THE PACIFIC WAVE TRAIN POINTED AT THE NRN INTERMOUNTAIN REGION. THE NRN PART OF THE FORECAST AREA IS ON THE EXTREME SRN FRINGE OF THIS ACTIVITY AND MOST LIKELY THERE IS NOT SUFFICIENT DYNAMICAL FORCING FOR MUCH IF ANY PCPN. BUT EXPECT A FEW CLOUDS ACROSS THE NORTH...AND GRADIENT FLOW WILL BE STRONG ENOUGH FOR SOME AFTERNOON BREEZES ACROSS THE NORTH. THE SYNOPTIC PATTERN SCREAMS MILD WEATHER THIS WEEKEND...SO MUCH SO THAT THE GFSX MOS GUIDANCE SHOW NEAR RECORD HIGH TEMPERATURES ON SUNDAY. HOW WARM?...HOW ABOUT LOWER 50S ACROSS THE UPPER YAMPA AND UPPER GUNNISON RIVER VALLEYS OR LOWER 60S IN THE DESERT VALLEYS OF SERN UTAH. WHEN DOES DECEMBER ARRIVE? && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 326 AM MST MON NOV 26 2012 LOCAL CIGS BKN010 OVER KSBS WITH MOUNTAIN TOPS PARTIALLY OBSCURED UNTIL 16Z...OTHERWISE VFR DOMINATES FOR EASTERN UTAH AND WESTERN COLORADO. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JAD LONG TERM...PF AVIATION...PF
AREA FORECAST DISCUSSION
NWS NEW YORK NY
100 AM EST MON NOV 26 2012 .SYNOPSIS... HIGH PRESSURE PASSES TO THE SOUTH THROUGH MONDAY...WHILE DEEPENING LOW PRESSURE LIFTS NORTH ACROSS THE CANADIAN MARITIMES. ANOTHER WEAKER LOW WILL PASS WELL SOUTH OF THE AREA TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CLOUDS HAVE BUILT BACK IN FROM THE NORTHWEST OVER THE LAST FEW HOURS...IN TURN SIGNIFICANTLY SLOWING RADIATIONAL COOLING ACROSS A LARGE PORTION OF THE AREA. THEREFORE...HAVE SLOWED THE RATE OF COOLING OVERNIGHT AND BUMPED UP THE LOWS A FEW DEGREES. MAINLY JUST THE INTERIOR SECTIONS SHOULD SEE TEMPS DIP INTO THE 20S. THE 03Z RAP HAS A FAIRLY GOOD HANDLE ON THE CLOUD COVER AND KEEPS IT IN PLACE UNTIL AROUND 09Z OR SO. BASED ON CURRENT TRENDS...THIS SEEMS PLAUSIBLE...SO HAVE ADJUSTED THE SKY FORECAST TO REFLECT THIS THINKING. REST OF FORECAST IS ON TRACK. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... A NEARLY ZONAL FLOW WILL SEND A DIGGING SHORT WAVE FROM THE NORTHERN PLAINS SOUTHEAST INTO THE MID SECTION OF THE COUNTRY BY MON NIGHT. MODELS HAVE TRENDED WEAKER AND FLATTER WITH THIS WAVE AS IT WILL AID THE DEVELOPMENT OF SURFACE LOW OVER THE TN VLY. THIS LOW WILL THEN TRACK NE TO OFF THE MID ATLANTIC COAST ON TUE. PRIOR TO THAT TIME...A DRY WESTERLY FLOW ON MON WILL ALLOW FOR PLENTY OF SUN WITH HIGHS REBOUNDING INTO THE UPPER 40S...STILL A FEW DEGREES BELOW NORMAL. CLOUDS WILL THEN BE ON THE INCREASE MON NIGHT IN ASSOC WITH THE AFOREMENTIONED LOW. THERE IS A SLIGHT CHC OF SNOW...POSSIBLY MIXED AT THE COAST DEVELOPING NEAR DAYBREAK. ANY PCPN WILL BE LIGHT WITH LITTLE OR NO ACCUMULATION. LOWS WILL RANGE FROM THE MID 20S WELL NORTH AND WEST...TO THE LOWER 30S COAST...AND MID 30S NYC METRO. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... OPERATIONAL MODELS AND GEFS ARE COMING INTO BETTER AGREEMENT ABOUT THE COASTAL LOW DEVELOPMENT AT THE BEGINNING OF THE LONG TERM PERIOD. A FIRST NORTHERN SHORTWAVE DIGS INTO THE MIDWEST MONDAY NIGHT AND BECOMES THE FOCUS FOR THE LOW DEVELOPMENT. AS IT TRACKS EAST...A WEAK SURFACE WAVE DEVELOPS NEAR THE DELMARVA REGION AND PRECIP EXPANDS NORTHWARD. THIS WAVE TRACKS EAST AND A SECOND NORTHERN SHORTWAVE THEN DIGS INTO THE TENNESSEE VALLEY...HELPING TO STRENGTHEN THE LOW PRESSURE EAST OF THE 40/70 LAT/LON BENCHMARK. WITH THESE TWO STREAMS NOT PHASING SOON ENOUGH...IT ALLOWS THE LOW TO STRENGTHEN FARTHER OFFSHORE TUESDAY NIGHT. EVEN WITH THE MODELS IN DECENT AGREEMENT...THERE ARE STILL VARIATIONS IN THE EXACT LOCATION OF THE LOW AND HOW CLOSE IT TRACKS TO THE COAST. THIS WILL EFFECT THE BOUNDARY LAYER TEMPERATURES...HOW MUCH PRECIP ACTUALLY MAKES IT OVER LAND AND THE TYPE OF PRECIP THAT FALLS. THE GFS HAS CONSISTENTLY BEEN A COOLER SOLUTION WITH THE ECMWF NOW FOLLOWING SUIT. THE NAM HAS A BOUNDARY LAYER A FEW DEGREES WARMER THAN THE OTHER MODELS...LEAVING A MOSTLY RAIN SOLUTION FOR THE COASTS/LONG ISLAND. THE KEY HERE IS THE BOUNDARY LAYER TEMPERATURES BECAUSE MUCH OF THE COLUMN IS COLD ENOUGH TO SUPPORT SNOW. AS FOR TYPE AND AMOUNTS OF PRECIP...GFS/GEFS/NAM/CMC HAVE BEEN SHOWING A CONSISTENTLY DRIER SOLUTION. ECMWF 00Z IS ONE OF THE WETTER AND SLOWER SOLUTIONS WITH THE 12Z COMING IN JUST SLIGHTLY DRIER THAN THE 00Z. THEREFORE...HAVE DROPPED QPF AMOUNTS OVERALL FOR THE SYSTEM AND KEPT MOST QPF ON TUESDAY WITH DRY WEATHER ON WEDNESDAY AS THE SYSTEM IS MOVING QUICKLY. HIGHER QPF AMOUNTS ARE EXPECTED ALONG LONG ISLAND/NYC/SOUTHERN CT AS THE LOW STRENGTHENS OFFSHORE. FOR THE LOWER HUDSON VALLEY/INTERIOR CT AND INTERIOR PORTIONS OF NE NJ...ALL SNOW IS EXPECTED BUT WITH THE LOW QPF VALUES...LIKELY WILL ONLY SEE 1-2 INCHES OF SNOW. HIGHER ELEVATIONS HAVE A CHANCE OF EXPERIENCING SLIGHTLY HIGHER AMOUNTS. FOR LONG ISLAND/NYC/COASTAL CT...TEMPERATURES ARE GOING TO BE RIGHT ON THE BORDER OF A RAIN/SNOW MIX OR RAIN EVENT. LOOKS TO START OUT AS A MIX...TRANSITION TO RAIN DURING THE DAY TUESDAY AND END TUESDAY NIGHT AS A RAIN/SNOW MIX AGAIN. IF A HEAVIER BAND OF PRECIP SETS UP OVER THOSE AREAS...COULD SEE A BRIEF PERIOD OF SNOWFALL BUT WILL NOT ACCUMULATE TO ANY MORE THAN A HALF AN INCH IF THAT OCCURS. THERE IS STILL UNCERTAINTY IN THE TEMPERATURES BECAUSE OF THE TRACK OF THE LOW AND SUBSEQUENT FORECASTS MAY MAKE CHANGES ACCORDINGLY. BEHIND THE COASTAL STORM...WINDS PICK UP WEDNESDAY AND THURSDAY AS THE LOW DEEPENS WELL OFFSHORE AND THE GRADIENT TIGHTENS BETWEEN IT AND THE HIGH PRESSURE BUILDING IN FROM THE WEST. THIS LARGE AREA OF HIGH PRESSURE COVERING MUCH OF THE EAST COAST WILL BUILD IN AT THE SURFACE AND MOSTLY ZONAL FLOW ALOFT RETURNS AS THE REMAINING UPPER LOW IN CANADA MOVES AWAY. HIGH TEMPERATURES DURING THE WEEK WILL REMAIN BELOW NORMAL WITH A BIT OF A WARM UP EXPECTED FOR THE WEEKEND AHEAD OF AN APPROACHING FRONTAL SYSTEM. LOWS FOR THE WEEK WILL REMAIN AT OR BELOW FREEZING FOR MOST OF THE AREA WITH LOWS WARMING UP INTO THE WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... DEEP LOW PRESSURE OVER EASTERN CANADA WILL MOVE SLOWLY NORTH THROUGH THIS AFTERNOON...WHILE HIGH PRESSURE BUILDS TO THE SOUTH. ANOTHER HIGH WILL BUILD IN FROM THE WEST LATE IN THE PERIOD AS A WAVE OF LOW PRESSURE APPROACHES FROM THE SW. VFR. BKN-OVC060 VFR CIGS LIKELY TO HANG ON UNTIL AT LEAST 10Z. WESTERLY FLOW WILL CONTINUE WITH WINDS 260-290 TRUE...BACKING TO 280-300 TRUE BY 15Z AND INCREASING TO 10-12 KT WITH GUSTS JUST SHY OF 20 KT. AFTER 21Z MON WINDS SHOULD DIMINISH AGAIN BELOW 10 KT... AND THEN BECOME LIGHT AND VARIABLE MON NIGHT. .OUTLOOK FOR 06Z TUE THROUGH FRI... .LATE MON NIGHT...VFR. .TUE...IFR CONDS POSSIBLE IN PRECIPITATION. KSWF/KHPN SHOULD REMAIN ALL SNOW WITH SOME LIGHT ACCUMULATION ON RUNWAYS...WHILE OTHER TERMINALS COULD SEE MORNING SNOW CHANGING TO AN AFTERNOON SNOW/RAIN MIX...THEN CHANGING BACK TO SNOW AT NIGHT...WITH LITTLE TO NO ACCUMULATION ON RUNWAYS. .WED...POSSIBLE MVFR CIGS IN THE MORNING. NW FLOW G20KT. .THU...VFR. WNW FLOW G20KT. .FRI...VFR. && .MARINE... WINDS AND SEAS WERE A BIT LOW ON THE OCEAN WATERS...SO MINOR ADJUSTMENTS UPWARD MADE EARLY THIS MORNING. SCA CONDITIONS CONTINUE ON THE OCEAN AND EASTERN WATERS THROUGH TONIGHT. SCA FOR SEAS MAY NEED TO BE EXTENDED ON THE EASTERN OCEAN WATERS FOR A LITTLE WHILE MON MORNING...BUT WILL WATCH TRENDS THE NEXT FEW HOURS AND ADDRESS THIS IN THE EARLY MORNING FORECAST PACKAGE. WINDS AND WAVES WILL REMAIN BELOW SCA CRITERIA AS HIGH PRESSURE IS OVERHEAD THROUGH TUESDAY AFTERNOON. AS THE LOW PRESSURE OFFSHORE ON TUESDAY DEEPENS...THE PRESSURE GRADIENT WILL TIGHTEN AND WINDS AND WAVES WILL PICK BACK UP. WINDS SHOULD BE ABOVE SCA CRITERIA BY TUESDAY NIGHT/WEDNESDAY MORNING AND WILL LIKELY CONTINUE THROUGH FRIDAY MORNING. WITH THE CONTINUED WINDS...WAVES WILL ALSO INCREASE AND COULD BE ABOVE 5FT BY THURSDAY MORNING. DUE TO THE UNCERTAINTY STILL WITH THE EXACT TRACK AND STRENGTH OF THE LOW... THE TIMING OF THE STRONGEST WINDS/HIGHEST WAVES MAY VARY SLIGHTLY && .HYDROLOGY... LOW PRESSURE AFFECTING THE REGION TUE INTO EARLY WED COULD BRING UP TO 1/4 INCH LIQUID QPF...WITH THE HIGHEST AMOUNTS ALONG THE COAST. SOME OF THIS MAY BE IN THE FORM OF SNOW WITH AMOUNTS UP TO AN INCH. && .TIDES/COASTAL FLOODING... A FULL MOON IS EXPECTED ON WED. BASED ON THE TRENDS OF TIMING... TRACK AND INTENSITY OF LOW PRESSURE EXPECTED TO AFFECT THE AREA TUE INTO EARLY WED...THE PROBABILITY FOR MINOR COASTAL FLOODING REMAINS LOW FOR VULNERABLE LOW-LYING LOCATIONS. && .EQUIPMENT... KOKX WSR-88D IS OUT OF SERVICE DUE TO A MAJOR NON STORM RELATED MECHANICAL FAILURE. OSF RADAR OPERATIONS CENTER TECHS HAVE ARRIVED TO BEGIN WORK...AND THE RADAR IS EXPECTED TO RETURN TO SERVICE BY THE FIRST WEEK OF DECEMBER. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ330-340-350-353-355. && $$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
815 PM EST TUE NOV 27 2012 .DISCUSSION... LATEST RAP ANALYSIS SHOWS THE APPROACHING H100-H70 FRONTAL TROF PUSHING INTO THE BIG BEND/ERN GOMEX REGION...PLACING CENTRAL FL UNDER ITS ASCENDING SIDE. ALOFT...A 110KT JET THRU THE H30-H20 LYR OVER THE PANHANDLE IS GENERATING WEAK TO MODERATE UPR LVL DIVERGENCE ALONG THE E FL COAST. WEAK ISENTROPIC LIFT ACRS THE ERN PENINSULA OCCURRING AS WELL. EVENING SOUNDINGS SHOW PWAT VALUES INCREASING FROM 1.0" AT KTBW TO 1.3" AT KJAX/KMFL...MOST OF IT BLO A SUBSIDENCE INVERSION IN THE H70-H60 LYR. THE COMBINATION OF WEAK LIFT AND LOW LVL MOISTURE HAS BEEN JUST ENOUGH TO SQUEEZE ISOLD/SCT SHRAS OUT OF THE AIRMASS S OF ORLANDO AND CAPE CANAVERAL. RADAR TREND SINCE SUNSET HAS SHOWN THESE SHRAS MOVING STEADILY EASTWARD...ESPECIALLY DOWNWIND OF LAKE OKEECHOBEE... BUT LITTLE IN THE WAY OF PRECIP OVER THE WRN PENINSULA THANKS TO A STREAM OF DRY H100-H70 AIR. CLOSER TO THE FRONT...PRECIP IS LIMITED TO THE PANHANDLE AND SHOWING NO SIGNS OF PUSHING INTO THE CENTRAL PENINSULA. GIVEN THE CURRENT SITUATION...HAVE UPDATED THE FCST TO INCLUDE CHC/SLGT CHC POPS FROM OSCEOLA/S BREVARD SWD THRU MIDNIGHT... MINOR ADJUSTMENTS TO SKY COVER AS WELL. REMAINDER OF THE FCST LOOKS GOOD. && .AVIATION... PREVAILING VFR IN MID/HIGH CLOUDS...BRIEF MVFR CIGS/VSBYS S OF KISM-KTIX THRU 28/05Z IN SCT SHRAS. && .MARINE... NO HIGHLIGHTS...NO SIG CHANGES. SFC/BNDRY LYR WNDS TO VEER TO W-NW OVERNIGHT AS A FRNTL BNDRY OVER THE PANHANDLE PUSHES THRU CNTRL FL...SPEEDS INCREASING TO 10-15KTS AREAWIDE BY DAYBREAK. FLOW WILL CONTINUE TO VEER DURING THE DAY ON WEDNESDAY...BCMG MORE N-NE BY AFTN...SPEEDS REACHING 15-20KTS. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...GLITTO
AREA FORECAST DISCUSSION...CORRECTION
NWS NORTHERN INDIANA
950 AM EST MON NOV 26 2012 .SHORT TERM... NO SENSIBLE WX CONCERNS THIS PD. WK SW OVR MT WILL AMPLIFY SEWD THIS PD AND EFFECTIVELY SHUNT SRN STREAM IMPULSE DOWN ALG THE GULF COAST AS COLD SFC RIDGE EXPANDS SEWD THROUGH THE OH VALLEY. AS A RESULT SECONDARY LL CAA SURGE TAKES PLACE TDA AND BROADER SCALE FLW VEERS MORE NRLY AND IN LIGHT OF CURRENT EXTENSIVE MID CLD SHIELD AND INCOMING SC DECK SEEPING SWD OUT OF WI/MI XPC A LIMITED DIURNAL. HWVR CLDS XPCD TO ERODE OUT OVERNIGHT AWAY FM LK MI AND W/SFC RIDGE BLDG IN PREFER COLDEST TEMP BLENDS W/SIMILAR XPCN FOR TUE. && .LONG TERM...WEDNESDAY THROUGH SUNDAY MAIN FOCUS THIS PERIOD REMAINS ON WARMING TREND AND LOW CHANCES FOR LIGHT RAIN SHOWERS FRIDAY INTO THE WEEKEND... AN UPPER TROUGH WILL DROP SOUTHEAST THROUGH THE NORTHERN GREAT LAKES TUESDAY NIGHT FORCING A WEAK COLD FRONT THROUGH THE LOCAL AREA EARLY WEDNESDAY MORNING. BRIEF VEERING OF LOW LEVEL WINDS TO WNW AND LAKE-8H TEMP DIFFERENTIALS IN THE 13-15C RANGE WILL LIKELY SUPPORT A DEVELOPING SCATTERED/BROKEN STRATOCU DECK NORTH OF HWY 30 ON WEDNESDAY. DRY PROFILE AND MARGINAL OVER LAKE INSTABILITY SHOULD MITIGATE SNOW POTENTIAL TO NOTHING MORE THAN A FEW FLURRIES ALONG AND NORTH OF I-80 IN INDIANA/MICHIGAN. THE LONGWAVE PATTERN WILL BECOME MORE ZONAL LATE THIS WEEK INTO NEXT WEEKEND. A SERIES OF LOW AMPLITUDE SHORTWAVE TROUGHS EMANATING OUT OF A LARGE CLOSED LOW OFF THE WEST COAST WILL PROPAGATE EAST THROUGH THE NORTHERN TIER OF THE US DAYS 5-7. EACH SYSTEM COULD BRING SOME LIGHT RAIN SHOWER ACTIVITY TO THE REGION...BEST CHANCES (15-30%) ACROSS THE NORTHERN HALF OF THE FA FRIDAY/FRIDAY NIGHT AND AGAIN SATURDAY NIGHT/SUNDAY MORNING PER LATEST MODEL ITERATIONS. AT THE SFC...GUIDANCE CONTINUES TO HINT AT A WEAK FRONTAL BOUNDARY DEVELOPING IN WEST TO EAST FASHION OVER OR JUST NORTH OF THE FA FRIDAY...LIFTING WELL NORTH OF THE LOCAL AREA OVER THE WEEKEND. THIS WILL ALLOW MUCH WARMER AIR TO ADVECT IN WITH HIGHS LIKELY REACHING THE UPPER 40S TO MID 50S BY SATURDAY. ECMWF/GFS ALSO CONTINUE TO BE VERY MOIST IN THE 925-850 MB LAYER WITHIN INCREASING SSW FLOW... WHICH SUPPORTS GOING MOSTLY CLOUDY TO CLOUDY SKY FCST ALONG WITH DECREASE IN DIURNAL TEMP RANGES. && .AVIATION... VFR CONDS TO START W/GRADUAL MOISTENING XPCD AT KSBN INTO THIS AFTN IN CONJUNCTION W/LL CAA SURGE AND VEERING LL FLW YIELDING AN INCREASING LK MSTR FLUX. 06Z TIMING OF MVFR CIG DVLPMNT MAY BE A BIT TOO OPTIMISTIC AS 07Z RUC OUTPUT INDICATES DVLPMNT AS EARLY AS 21Z. OTHERWISE LWR BOUND VFR RANGE SC CLD DVLPMNT TIMING AT KFWA ON TARGET. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...T
AREA FORECAST DISCUSSION...CORRECTION
NWS NORTHERN INDIANA
343 AM EST MON NOV 26 2012 .SHORT TERM... NO SENSIBLE WX CONCERNS THIS PD. WK SW OVR MT WILL AMPLIFY SEWD THIS PD AND EFFECTIVELY SHUNT SRN STREAM IMPULSE DOWN ALG THE GULF COAST AS COLD SFC RIDGE EXPANDS SEWD THROUGH THE OH VALLEY. AS A RESULT SECONDARY LL CAA SURGE TAKES PLACE TDA AND BROADER SCALE FLW VEERS MORE NRLY AND IN LIGHT OF CURRENT EXTENSIVE MID CLD SHIELD AND INCOMING SC DECK SEEPING SWD OUT OF WI/MI XPC A LIMITED DIURNAL. HWVR CLDS XPCD TO ERODE OUT OVERNIGHT AWAY FM LK MI AND W/SFC RIDGE BLDG IN PREFER COLDEST TEMP BLENDS W/SIMILAR XPCN FOR TUE. BENIGN WX THIS PD AS SFC RIDGE BLDS SEWD OUT OF SRN CANADA IN BEHIND WK SW DEAMPLIFYING EWD THROUGH THE NRN LAKES TDA. AND OTHER THAN CURRENT PATCH OF MID CLDS THAT EXTENDS WWD INTO ERN IA...XPC CLRG THIS AFTN IN ASSOCN/W LG SCALE DRY SLOT PROGRESSING SEWD OUT OF MN. MODEST WAA PUSH AHD OF THIS SYS WILL MAKE FOR QUITE A BIT WARMER TEMPS COMPARED TO YDA W/GENERAL LOW 40S XPCD. && .LONG TERM...WEDNESDAY THROUGH SUNDAY MAIN FOCUS THIS PERIOD REMAINS ON WARMING TREND AND LOW CHANCES FOR LIGHT RAIN SHOWERS FRIDAY INTO THE WEEKEND... AN UPPER TROUGH WILL DROP SOUTHEAST THROUGH THE NORTHERN GREAT LAKES TUESDAY NIGHT FORCING A WEAK COLD FRONT THROUGH THE LOCAL AREA EARLY WEDNESDAY MORNING. BRIEF VEERING OF LOW LEVEL WINDS TO WNW AND LAKE-8H TEMP DIFFERENTIALS IN THE 13-15C RANGE WILL LIKELY SUPPORT A DEVELOPING SCATTERED/BROKEN STRATOCU DECK NORTH OF HWY 30 ON WEDNESDAY. DRY PROFILE AND MARGINAL OVER LAKE INSTABILITY SHOULD MITIGATE SNOW POTENTIAL TO NOTHING MORE THAN A FEW FLURRIES ALONG AND NORTH OF I-80 IN INDIANA/MICHIGAN. THE LONGWAVE PATTERN WILL BECOME MORE ZONAL LATE THIS WEEK INTO NEXT WEEKEND. A SERIES OF LOW AMPLITUDE SHORTWAVE TROUGHS EMANATING OUT OF A LARGE CLOSED LOW OFF THE WEST COAST WILL PROPAGATE EAST THROUGH THE NORTHERN TIER OF THE US DAYS 5-7. EACH SYSTEM COULD BRING SOME LIGHT RAIN SHOWER ACTIVITY TO THE REGION...BEST CHANCES (15-30%) ACROSS THE NORTHERN HALF OF THE FA FRIDAY/FRIDAY NIGHT AND AGAIN SATURDAY NIGHT/SUNDAY MORNING PER LATEST MODEL ITERATIONS. AT THE SFC...GUIDANCE CONTINUES TO HINT AT A WEAK FRONTAL BOUNDARY DEVELOPING IN WEST TO EAST FASHION OVER OR JUST NORTH OF THE FA FRIDAY...LIFTING WELL NORTH OF THE LOCAL AREA OVER THE WEEKEND. THIS WILL ALLOW MUCH WARMER AIR TO ADVECT IN WITH HIGHS LIKELY REACHING THE UPPER 40S TO MID 50S BY SATURDAY. ECMWF/GFS ALSO CONTINUE TO BE VERY MOIST IN THE 925-850 MB LAYER WITHIN INCREASING SSW FLOW... WHICH SUPPORTS GOING MOSTLY CLOUDY TO CLOUDY SKY FCST ALONG WITH DECREASE IN DIURNAL TEMP RANGES. && .AVIATION... VFR CONDS TO START W/GRADUAL MOISTENING XPCD AT KSBN INTO THIS AFTN IN CONJUNCTION W/LL CAA SURGE AND VEERING LL FLW YIELDING AN INCREASING LK MSTR FLUX. 06Z TIMING OF MVFR CIG DVLPMNT MAY BE A BIT TOO OPTIMISTIC AS 07Z RUC OUTPUT INDICATES DVLPMNT AS EARLY AS 21Z. OTHERWISE LWR BOUND VFR RANGE SC CLD DVLPMNT TIMING AT KFWA ON TARGET. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...T
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
940 PM EST TUE NOV 27 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH WEDNESDAY/... AN INTERESTING DICHOTOMY EXISTS AMONGST DYNAMICAL GUIDANCE THIS EVENING WITH THE RAP SUGGESTING LOW CLOUDS LINGERING FAR LONGER THAN THE USUAL NAM/GFS WOULD INDICATE. THE MAIN CULPRIT BEHIND THE RAP HOLDING ONTO CLOUDS LONGER IS A RATHER STUBBORN INVERSION ON THE MODEL AROUND 3 KFT OR SO THAT DOES SEEM TO BE VERIFYING AT THE MOMENT FAIRLY WELL. THIS IS VERIFIED VIA THE INFRARED FOG PRODUCT (11-3.9 MICRON) AS THE BACK EDGE OF THE LOW CLOUDS ARE EVER-SO- SLOWLY EEKING EAST TOWARD ZANESVILLE AND NEW PHILADELPHIA...WHICH MEANS ITS MADE LESS THAN A COUNTY OF PROGRESS IN THE LAST THREE HOURS. ADJUSTMENTS TO THE GRIDS WERE MADE TO MAKE THIS EASTWARD PROGRESS EXTREMELY SLOW OVERNIGHT...LEAVING MOST OF THE FORECAST AREA MOSTLY CLOUDY THROUGH THE NIGHT. WITH EXPECTATIONS OF MORE STRATOCUMULUS LINGERING OVERNIGHT...LOWS WERE GENERALLY ADJUSTED NOMINALLY UPWARD...EXCEPT ACROSS THE ZANESVILLE/COSHOCTON AREAS. FRIES && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... H8 FLOW IS EXPECTED TO BECOME ANTICYCLONIC WEDNESDAY EVENING... LIMITING ANY LAKE EFFECT POTENTIAL TO JUST AN ISOLATED SNOW SHOWER OR TWO ACROSS THE NORTH. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /SATURDAY THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A STRATOCUMULUS DECK WILL PREVAIL ACROSS ALL OF THE TERMINALS EXCEPT KZZV OVERNIGHT AS LOW-LEVEL MOISTURE BECOMES TRAPPED UNDER AN INVERSION. CEILINGS WILL PREVAIL MOSTLY AT 2500-3000FT OVERNIGHT WITH THE CLOCK DECK BEGINNING TO ERODE FROM THE WEST AROUND DAWN. CONFIDENCE IN HOW LONG CEILINGS WILL PREVAIL OVERNIGHT IS LOW AS LAMP/HRRR/NARRE-TL GUIDANCE INDICATE CEILINGS ERODING FROM THE WEST AND BREAKING ACROSS THE TERMINALS BY 06Z. THE TAFS...HOWEVER...INDICATE MVFR PREVAILING UNTIL AROUND 12Z WITH THE SUPPORT OF RECENT SATELLITE TRENDS AND MODEL SOUNDINGS. SUBSIDENCE FROM HIGH PRESSURE BUILDING IN FROM THE SOUTHWEST WILL ALLOW CEILINGS TO BREAK BY MID-MORNING WEDNESDAY WITH VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME NEAR CALM OVERNIGHT. WINDS WILL BECOME MORE WESTERLY ON WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING. .OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
653 PM EST TUE NOV 27 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH WEDNESDAY/... AN INTERESTING DICHOTOMY EXISTS AMONGST DYNAMICAL GUIDANCE THIS EVENING WITH THE RAP SUGGESTING LOW CLOUDS LINGERING FAR LONGER THAN THE USUAL NAM/GFS WOULD INDICATE. THE MAIN CULPRIT BEHIND THE RAP HOLDING ONTO CLOUDS LONGER IS A RATHER STUBBORN INVERSION ON THE MODEL AROUND 3 KFT OR SO THAT DOES SEEM TO BE VERIFYING AT THE MOMENT FAIRLY WELL. THIS IS VERIFIED VIA THE INFRARED FOG PRODUCT (11-3.9 MICRON) AS THE BACK EDGE OF THE LOW CLOUDS ARE EVER-SO- SLOWLY EEKING EAST TOWARD ZANESVILLE AND NEW PHILADELPHIA AT THIS HOUR. ADJUSTMENTS TO THE GRIDS WERE MADE TO MAKE THIS EASTWARD PROGRESS EXTREMELY SLOW OVERNIGHT...LEAVING MOST OF THE FORECAST AREA MOSTLY CLOUDY THROUGH THE NIGHT. WITH EXPECTATIONS OF MORE STRATOCUMULUS LINGERING OVERNIGHT...LOWS WERE GENERALLY ADJUSTED NOMINALLY UPWARD...EXPECT ACROSS THE ZANESVILLE/COSHOCTON AREAS. FRIES && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... H8 FLOW IS EXPECTED TO BECOME ANTICYCLONIC WEDNESDAY EVENING... LIMITING ANY LAKE EFFECT POTENTIAL TO JUST AN ISOLATED SNOW SHOWER OR TWO ACROSS THE NORTH. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /SATURDAY THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... A STRATOCUMULUS DECK WILL PREVAIL ACROSS ALL OF THE TERMINALS EXCEPT KZZV OVERNIGHT AS LOW-LEVEL MOISTURE BECOMES TRAPPED UNDER AN INVERSION. CEILINGS WILL PREVAIL MOSTLY AT 2500-3000FT OVERNIGHT WITH THE CLOCK DECK BEGINNING TO ERODE FROM THE WEST AROUND DAWN. CONFIDENCE IN HOW LONG CEILINGS WILL PREVAIL OVERNIGHT IS LOW AS LAMP/HRRR/NARRE-TL GUIDANCE INDICATE CEILINGS ERODING FROM THE WEST AND BREAKING ACROSS THE TERMINALS BY 06Z. THE TAFS...HOWEVER...INDICATE MVFR PREVAILING UNTIL AROUND 12Z WITH THE SUPPORT OF RECENT SATELLITE TRENDS AND MODEL SOUNDINGS. SUBSIDENCE FROM HIGH PRESSURE BUILDING IN FROM THE SOUTHWEST WILL ALLOW CEILINGS TO BREAK BY MID-MORNING WEDNESDAY WITH VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME NEAR CALM OVERNIGHT. WINDS WILL BECOME MORE WESTERLY ON WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING. .OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
416 PM EST MON NOV 26 2012 .SYNOPSIS... A WEAK SURFACE LOW WILL MOVE FROM THE GULF STATES INTO THE MID- ATLANTIC TONIGHT INTO TUESDAY...WITH ACCUMULATING SNOW PRIMARILY SOUTHEAST OF PITTSBURGH FOR THE COMMUTE TUESDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST WILL THEN ALLOW FOR A MOSTLY DRY REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A ZONAL FLOW. AN ELONGATED VORT LOBE IS SLIDING ACROSS THE GREAT LAKES. AT THE SURFACE...LOCALLY THE REGION IS UNDER A BROAD AREA OF HIGH PRESSURE BETWEEN HIGHS CENTERED ACROSS THE NORTHERN PLAINS AND THE SOUTHEAST. UPSTREAM...A 1010MB LOW IS DEVELOPING ACROSS ARKANSAS. A FRONTAL BOUNDARY EXTENDS NORTHEAST OF THIS FEATURE INTO KY/TN. TONIGHT INTO TUESDAY...THE SURFACE LOW ACROSS ARKANSAS WILL TRACK ACROSS THE GULF STATES INTO THE SOUTHERN APPALACHIANS BY 12Z TUESDAY AND QUICKLY LIFT INTO THE MID-ATLANTIC BY TUESDAY EVENING. 700MB OMEGA SUPPORTS FORCING MOVING INTO NORTH-CENTRAL WV AND THE SOUTHEAST RIDGES BY 06Z WITH THE WEAK INVERTED TROUGH ASSOCIATED WITH THE LOW AND OVERRUNNING AHEAD OF THE LOW. FORCING APPEARS SUFFICIENT FOR AROUND 0.25-0.35 QPF SOUTHEAST OF PITTSBURGH WITH THIS SYSTEM BETWEEN AROUND 03Z AND 15Z TUESDAY. MODEL THICKNESSES AND SOUNDINGS SUPPORT THAT THERMAL PROFILE WILL BE COLD ENOUGH FOR PRECIP TO BE MOSTLY SNOW WITH THIS SYSTEM. 1000-850MB 1300M LINE PUSHING INTO SOUTHWEST PA AND 1000-500MB 5400M LINE ALONG THE MASON- DIXON LINE MAY ALLOW FOR SOME RAIN TO MIX IN ACROSS NORTH-CENTRAL WV INITIALLY. DYNAMIC COOLING SHOULD ALLOW PRECIP TO TURN TO ALL SNOW THERE FAIRLY QUICKLY. BELIEVE SLIGHT ELEVATION ENHANCEMENT ALONG WITH 10:1-12:1 SNOW-TO-LIQUID RATIOS WILL CONTRIBUTE TO MAKE THIS AN ADVISORY SNOWFALL EVENT FOR THE RIDGES. IN ADDITION...THE TIMING OF THIS EVENT...AROUND THE MORNING COMMUTE...WILL INCREASE THE IMPACTS OF THIS SNOWFALL. FOR SNOW AMOUNTS...FORECAST IS ON THE HIGH END OF GUIDANCE...TAKING INTO ACCOUNT THE BETTER RESOLUTION OF THE 12KM NAM AND HOW ITS HANDLING OF ENHANCED PRECIP ACROSS THE RIDGES. WITH THAT IN MIND ALONG WITH THE 12Z GFS COMING IN WITH MARGINAL ADVISORY CRITERIA...ANTICIPATE 2 TO 5 INCHES ACROSS PRESTON...TUCKER...AND GARRETT COUNTIES WITH THE HIGHEST AMOUNTS ALONG THE HIGHEST RIDGES. THUS...A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THESE LOCATIONS. GENERALLY 1 TO 2 INCHES OF SNOW IS FORECAST FOR A TIER OF COUNTIES TO THE WEST...WHICH WOULD BE A SUFFICIENT AMOUNT OF SNOW TO ALSO IMPACT THE MORNING COMMUTE...ALBEIT WITH SUB-ADVISORY LEVELS. AN SPS HAS BEEN ISSUED FOR THOSE COUNTIES. THERE IS STILL SOME UNCERTAINTY IN TO HOW FAR NORTHWEST LIGHT SNOW ACCUMULATION WILL EXTEND...AS GFS BRING 1-2 INCHES TO THE PITTSBURGH METRO. WEAK SHORT WAVE MOVING ACROSS THE OHIO VALLEY MAY ALSO INFLUENCE LIGHT ACCUMULATIONS. AT THIS TIME...ACROSS THE PITTSBURGH METRO AND TO THE NORTH AND WEST...LESS THAN AN INCH IS FORECAST. WILL NEED TO MONITOR FOR POTENTIAL MORNING COMMUTE IMPACTS THERE. PRECIP WITH THIS SYSTEM LOOKS TO SHIFT EAST OF THE AREA BY 18Z TUESDAY WITH A DRY REMAINDER OF THE DAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST. FOR TEMPS...LAMP GUIDANCE SEEMS REASONABLE SOUTHEAST OF PITTSBURGH WITH LOWS IN THE UPPER 20S TO LOWER 30S. FURTHER NORTH...WENT A FEW DEGREES BELOW GUIDANCE FOR LOWS IN THE MID 20S. CLOUD COVERAGE WILL CONTRIBUTE TO LIMIT TEMPS FOR HIGHS ON TUESDAY...GENERALLY IN THE MID TO UPPER 30S ACROSS THE AREA. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... THERE IS STRONG GFS/ECWMF/NAM AGREEMENT THAT A SURFACE HIGH WILL DOMINATE THE UPPER OHIO VALLEY THROUGH THIS PERIOD WITH A WEAK MID-LEVEL TROUGH PASSING NORTH OF THE AREA ON WEDNESDAY. THUS...THE FORECAST IS DRY THROUGH THE MAJORITY OF THIS PERIOD. THE ONE EXCEPTION IS ACROSS AREAS ALONG AND NORTH OF I-80 ON WEDNESDAY WITH THE TROUGH. THICKNESSES ARE LOW ENOUGH FOR SNOW SHOWERS AS PRECIP MAY CLIP THE NORTHERN FRINGE OF THE FORECAST AREA WITH THIS SYSTEM. WITH THIS IN MIND...WENT WITH SCHC POPS ALONG AND NORTH OF I-80 AND CHC POPS IN FOREST COUNTY ON WEDNESDAY. 850MB TEMPS INCREASE FROM AROUND -6C ON WEDNESDAY TO 0C ON THURSDAY AND THUS HIGHS WILL BE PROGRESSIVELY WARMER WITH PLENTY OF SUN THROUGH THE MID-WEEK. STILL...HIGHS WILL BE AROUND 5 DEGREES BELOW SEASONAL NORMS. LOWS TUESDAY NIGHT ARE COOLEST WEST OF I-77, CLOSER TO THE CENTER OF THE HIGH AND ALSO ALONG THE EASTERN RIDGES. THERE TEMPS MAY COOL INTO THE UPPER TEENS WITH LOW TO MID 20S ELSEWHERE. AS THE HIGH SHIFTS EASTWARD...THE COOLEST TEMPS WILL BE ACROSS THE SOUTHEASTERN RIDGES ON WEDNESDAY NIGHT WITH TEMPS AROUND 10 DEGREES BELOW NORMAL ACROSS THE AREA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... UNFORTUNATELY...LONG TERM FORECAST IS LACKING CONSISTENCY BETWEEN 12Z MODELS...SO CONFIDENCE IS BELOW AVERAGE. THE PERIOD BEGINS WITH HIGH PRESSURE CENTERED OFF THE NORTH CAROLINA COAST. FROM THERE...MODELS DIVERGE. DEPENDING ON THE MODEL CHOICE...THERE COULD BE A POSSIBILITY OF PRECIPITATION ANY TIME FROM FRIDAY AFTERNOON THROUGH MONDAY. AS A RESULT...GENERALLY WENT WITH AT LEAST SLIGHT CHANCE POPS THROUGH THE PERIOD...BUMPING UP POPS TO CHANCE SATURDAY NIGHT THROUGH SUNDAY NIGHT. THAT PORTION OF THE FORECAST IS ESSENTIALLY PERSISTENCE FROM THE INHERITED FORECAST. HOWEVER...MODELS ARE IN AGREEMENT ABOUT A WARMING TREND. WHILE FRIDAY WILL BE A COUPLE DEGREES BELOW NORMAL...EXPECT NEAR NORMAL TEMPERATURES ON SATURDAY...AND ABOVE NORMAL TEMPERATURES FOR SUNDAY AND MONDAY. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... HIGH PRESSURE WILL BRING VFR CONDITIONS THROUGH THIS EVENING. AN AREA OF LOW PRESSURE WILL MOVE NE FROM THE TN/MS VALLEY RGN INTO VIRGINIA TONIGHT INTO TUESDAY MORNING. THIS SHOULD BRING MVFR VISIBILITIES AND CEILINGS TO MOST OF THE TERMINALS AS LIGHT SNOW MOVES INTO THE REGION. MGW MAY SEE SOME IFR TOWARD DAYBREAK TUESDAY...HOWEVER ENOUGH UNCERTAINTY TO KEEP IT LOW END MVFR FOR NOW. .OUTLOOK.../TUESDAY THROUGH SATURDAY/... THE LOW WILL MOVE OUT OF THE REGION BY TUESDAY AFTERNOON...FOLLOWED BY HIGH PRESSURE AND VFR CONDITIONS THROUGH FRIDAY. NON VFR POSSIBLE SATURDAY AS A WARM FRONT MOVES NWD ACROSS THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR WVZ023-041. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM SHORT TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
105 PM EST MON NOV 26 2012 .SYNOPSIS... A BROAD AREA OF HIGH PRESSURE WILL ALLOW FOR A DRY START TO THE WEEK. A WEAK SURFACE LOW WILL MOVE FROM GULF STATES INTO THE MID-ATLANTIC TONIGHT INTO TUESDAY...WITH SOME ACCUMULATING SNOW SOUTHEAST OF PITTSBURGH FOR THE COMMUTE TUESDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST WILL THEN ALLOW FOR A MOSTLY DRY REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AN UPDATE HAS BEEN ISSUED FOR THE NEW ISSUANCE OF A WINTER WEATHER ADVISORY FOR THE RIDGES OF WV/MD. OTHERWISE...PREVIOUS DISCUSSION REMAINS THE SAME. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A ZONAL FLOW. A WEAK ELONGATED VORT LOBE IS SLIDING ACROSS THE SOUTHERN GREAT LAKES. WITH THE WEAK NATURE OF THIS FEATURE...THERE ARE ONLY MID DECK CLOUDS IN ITS ASSOCIATION. AT THE SURFACE...LOCALLY THE REGION IS UNDER A BROAD AREA OF HIGH PRESSURE BETWEEN HIGHS CENTERED ACROSS THE NORTHERN PLAINS AND THE SOUTHEAST. UPSTREAM...A 1010MB LOW IS DEVELOPING ACROSS TEXAS. A FRONTAL BOUNDARY EXTENDS NORTHEAST OF THIS FEATURE INTO KY/TN. WEAK HIGH PRESSURE WILL REMAIN IN CONTROL TODAY WITH CLOUD COVERAGE LIMITED TO SOME MID DECK AS THE AFOREMENTIONED H5 VORT SLIDES NORTHEAST OF THE AREA. FOR TEMPS...RECENT TRENDS...ABUNDANT SUNSHINE THIS MORNING...ALONG WITH LAMP GUIDANCE HAVE LED TO TEMPS BEING ADJUSTED UP A DEGREE ACROSS THE AREA AND 2-3 DEGREES SOUTH OF I-70. HIGHS TODAY WILL RANGE FROM THE UPPER 30S NORTH OF I-80 TO THE UPPER 40S ACROSS THE LOWLANDS SOUTH OF I-70. TONIGHT INTO TUESDAY...THE SURFACE LOW ACROSS TEXAS WILL TRACK ACROSS THE GULF STATES INTO THE SOUTHERN APPALACHIANS BY 12Z TUESDAY AND QUICKLY LIFT INTO THE MID-ATLANTIC BY 18Z. 700MB OMEGA SUPPORTS FORCING MOVING INTO NORTH-CENTRAL WV AND THE SOUTHEAST RIDGES BY 06Z WITH THE WEAK INVERTED TROUGH ASSOCIATED WITH THE LOW AND OVERRUNNING AHEAD OF THE LOW. FORCING APPEARS SUFFICIENT FOR AROUND 0.25-0.35 QPF SOUTHEAST OF PITTSBURGH WITH THIS SYSTEM BETWEEN AROUND 03Z AND 15Z TUESDAY. MODEL THICKNESSES AND SOUNDINGS SUPPORT THAT THERMAL PROFILE WILL BE COLD ENOUGH FOR PRECIP TO BE ALL SNOW WITH THIS SYSTEM. WITH THIS IN MIND...BELIEVE SLIGHT ELEVATION ENHANCEMENT ALONG WITH 10:1-12:1 SNOW-TO-LIQUID RATIOS WILL CONTRIBUTE TO MAKE THIS AN ADVISORY SNOWFALL EVENT. IN ADDITION...THE TIMING OF THIS EVENT...AROUND THE MORNING COMMUTE...WILL INCREASE THE IMPACTS OF THIS SNOWFALL. FOR SNOW AMOUNTS...FORECAST IS ON THE HIGH END OF GUIDANCE...TAKING INTO ACCOUNT THE BETTER RESOLUTION OF THE 12KM NAM AND HOW ITS RESOLVING ENHANCED PRECIP ACROSS THE RIDGES. WITH THAT IN MIND ALONG WITH THE 12Z GFS COMING IN WITH MARGINAL ADVISORY CRITERIA...ANTICIPATE 2 TO 5 INCHES ACROSS PRESTON...TUCKER...AND GARRETT COUNTIES WITH THE HIGHEST AMOUNTS ALONG THE HIGHEST RIDGES. THUS...A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THESE LOCATIONS. GENERALLY 1 TO 2 INCHES OF SNOW IS FORECAST FOR A TIER OF COUNTIES TO THE WEST...WHICH WOULD BE A SUFFICIENT AMOUNT OF SNOW TO ALSO IMPACT THE MORNING COMMUTE...ALBEIT WITH SUB-ADVISORY LEVELS. OTHERWISE...ACROSS THE PITTSBURGH METRO AND TO THE NORTH AND WEST...EXPECT LITTLE OR NO ACCUMULATION. PRECIP WITH THIS SYSTEM LOOKS TO SHIFT EAST OF THE AREA BY 18Z TUESDAY WITH A DRY REMAINDER OF THE DAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST. FOR TEMPS...LAMP GUIDANCE SEEMS REASONABLE SOUTHEAST OF PITTSBURGH WITH LOWS IN THE UPPER 20S TO LOWER 30S. FURTHER NORTH...WENT A FEW DEGREES BELOW GUIDANCE FOR LOWS IN THE MID 20S. CLOUD COVERAGE WILL CONTRIBUTE TO LIMIT TEMPS FOR HIGHS ON TUESDAY...GENERALLY IN THE MID TO UPPER 30S ACROSS THE AREA. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY WITH A DRY AND COLD TUESDAY NIGHT EXPECTED. A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS ONTARIO AND THE EASTERN GREAT LAKES ON WEDNESDAY. SYNOPTIC MOISTURE WILL MAKE ITS WAY INTO THE NORTHERN COUNTIES...BUT THIS MAY ONLY PROVIDE CLOUDS AND NO PRECIPITATION. IT REMAINS TO BE SEEN WHETHER WINDS WILL ALIGN TO PROVIDE LAKE MOISTURE BEFORE THE SHORTWAVE PUSHES EAST OF THE REGION. WILL PROBABLY JUST KEEP SLIGHT CHANCE POPS FOR NOW. NOT MUCH IMPROVEMENT WITH TEMPERATURES WEDNESDAY WITH TEMPS ABOUT 5-10 DEGREES BELOW NORMAL THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... A LARGE SURFACE HIGH WILL BRING CHILLY CONDITIONS MID WEEK. THEN BY LATE WEEK THERE WILL BE A RETURN OF SOUTHERLY SURFACE WINDS ON THE BACKSIDE OF HIGH PRESSURE WILL TAKE TEMPERATURES BACK TO NORMAL. HIGHS WILL PUSH BACK UP INTO THE UPPER 40S AND LOWER 50S TOWARD THE END OF THE PERIOD. DRY CONDITIONS THROUGH SATURDAY NIGHT..THEN A CHANCE OF SHOWERS AHEAD OF NEXT SYSTEM ON SUNDAY IN WEST. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... HIGH PRESSURE WILL BRING VFR CONDITIONS THROUGH THIS EVENING. AN AREA OF LOW PRESSURE WILL MOVE NE FROM THE TN/MS VALLEY RGN INTO VIRGINIA TONIGHT INTO TUESDAY MORNING. THIS SHOULD BRING MVFR VISIBILITIES AND CEILINGS TO MOST OF THE TERMINALS AS LIGHT SNOW MOVES INTO THE REGION. MGW MAY SEE SOME IFR TOWARD DAYBREAK TUESDAY...HOWEVER ENOUGH UNCERTAINTY TO KEEP IT LOW END MVFR FOR NOW. .OUTLOOK.../TUESDAY THROUGH SATURDAY/... THE LOW WILL MOVE OUT OF THE REGION BY TUESDAY AFTERNOON...FOLLOWED BY HIGH PRESSURE AND VFR CONDITIONS THROUGH FRIDAY. NON VFR POSSIBLE SATURDAY AS A WARM FRONT MOVES NWD ACROSS THE REGION. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1204 PM EST MON NOV 26 2012 .SYNOPSIS... A BROAD AREA OF HIGH PRESSURE WILL ALLOW FOR A DRY START TO THE WEEK. A WEAK SURFACE LOW WILL MOVE FROM GULF STATES INTO THE MID-ATLANTIC TONIGHT INTO TUESDAY...WITH SOME ACCUMULATING SNOW SOUTHEAST OF PITTSBURGH FOR THE COMMUTE TUESDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST WILL THEN ALLOW FOR A MOSTLY DRY REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AN UPDATE HAS BEEN ISSUED FOR THE NEW ISSUANCE OF A WINTER WEATHER ADVISORY FOR THE RIDGES OF WV/MD. OTHERWISE...PREVIOUS DISCUSSION REMAINS THE SAME. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A ZONAL FLOW. A WEAK ELONGATED VORT LOBE IS SLIDING ACROSS THE SOUTHERN GREAT LAKES. WITH THE WEAK NATURE OF THIS FEATURE...THERE ARE ONLY MID DECK CLOUDS IN ITS ASSOCIATION. AT THE SURFACE...LOCALLY THE REGION IS UNDER A BROAD AREA OF HIGH PRESSURE BETWEEN HIGHS CENTERED ACROSS THE NORTHERN PLAINS AND THE SOUTHEAST. UPSTREAM...A 1010MB LOW IS DEVELOPING ACROSS TEXAS. A FRONTAL BOUNDARY EXTENDS NORTHEAST OF THIS FEATURE INTO KY/TN. WEAK HIGH PRESSURE WILL REMAIN IN CONTROL TODAY WITH CLOUD COVERAGE LIMITED TO SOME MID DECK AS THE AFOREMENTIONED H5 VORT SLIDES NORTHEAST OF THE AREA. FOR TEMPS...RECENT TRENDS...ABUNDANT SUNSHINE THIS MORNING...ALONG WITH LAMP GUIDANCE HAVE LED TO TEMPS BEING ADJUSTED UP A DEGREE ACROSS THE AREA AND 2-3 DEGREES SOUTH OF I-70. HIGHS TODAY WILL RANGE FROM THE UPPER 30S NORTH OF I-80 TO THE UPPER 40S ACROSS THE LOWLANDS SOUTH OF I-70. TONIGHT INTO TUESDAY...THE SURFACE LOW ACROSS TEXAS WILL TRACK ACROSS THE GULF STATES INTO THE SOUTHERN APPALACHIANS BY 12Z TUESDAY AND QUICKLY LIFT INTO THE MID-ATLANTIC BY 18Z. 700MB OMEGA SUPPORTS FORCING MOVING INTO NORTH-CENTRAL WV AND THE SOUTHEAST RIDGES BY 06Z WITH THE WEAK INVERTED TROUGH ASSOCIATED WITH THE LOW AND OVERRUNNING AHEAD OF THE LOW. FORCING APPEARS SUFFICIENT FOR AROUND 0.25-0.35 QPF SOUTHEAST OF PITTSBURGH WITH THIS SYSTEM BETWEEN AROUND 03Z AND 15Z TUESDAY. MODEL THICKNESSES AND SOUNDINGS SUPPORT THAT THERMAL PROFILE WILL BE COLD ENOUGH FOR PRECIP TO BE ALL SNOW WITH THIS SYSTEM. WITH THIS IN MIND...BELIEVE SLIGHT ELEVATION ENHANCEMENT ALONG WITH 10:1-12:1 SNOW-TO-LIQUID RATIOS WILL CONTRIBUTE TO MAKE THIS AN ADVISORY SNOWFALL EVENT. IN ADDITION...THE TIMING OF THIS EVENT...AROUND THE MORNING COMMUTE...WILL INCREASE THE IMPACTS OF THIS SNOWFALL. FOR SNOW AMOUNTS...FORECAST IS ON THE HIGH END OF GUIDANCE...TAKING INTO ACCOUNT THE BETTER RESOLUTION OF THE 12KM NAM AND HOW ITS RESOLVING ENHANCED PRECIP ACROSS THE RIDGES. WITH THAT IN MIND ALONG WITH THE 12Z GFS COMING IN WITH MARGINAL ADVISORY CRITERIA...ANTICIPATE 2 TO 5 INCHES ACROSS PRESTON...TUCKER...AND GARRETT COUNTIES WITH THE HIGHEST AMOUNTS ALONG THE HIGHEST RIDGES. THUS...A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THESE LOCATIONS. GENERALLY 1 TO 2 INCHES OF SNOW IS FORECAST FOR A TIER OF COUNTIES TO THE WEST...WHICH WOULD BE A SUFFICIENT AMOUNT OF SNOW TO ALSO IMPACT THE MORNING COMMUTE...ALBEIT WITH SUB-ADVISORY LEVELS. OTHERWISE...ACROSS THE PITTSBURGH METRO AND TO THE NORTH AND WEST...EXPECT LITTLE OR NO ACCUMULATION. PRECIP WITH THIS SYSTEM LOOKS TO SHIFT EAST OF THE AREA BY 18Z TUESDAY WITH A DRY REMAINDER OF THE DAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST. FOR TEMPS...LAMP GUIDANCE SEEMS REASONABLE SOUTHEAST OF PITTSBURGH WITH LOWS IN THE UPPER 20S TO LOWER 30S. FURTHER NORTH...WENT A FEW DEGREES BELOW GUIDANCE FOR LOWS IN THE MID 20S. CLOUD COVERAGE WILL CONTRIBUTE TO LIMIT TEMPS FOR HIGHS ON TUESDAY...GENERALLY IN THE MID TO UPPER 30S ACROSS THE AREA. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY WITH A DRY AND COLD TUESDAY NIGHT EXPECTED. A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS ONTARIO AND THE EASTERN GREAT LAKES ON WEDNESDAY. SYNOPTIC MOISTURE WILL MAKE ITS WAY INTO THE NORTHERN COUNTIES...BUT THIS MAY ONLY PROVIDE CLOUDS AND NO PRECIPITATION. IT REMAINS TO BE SEEN WHETHER WINDS WILL ALIGN TO PROVIDE LAKE MOISTURE BEFORE THE SHORTWAVE PUSHES EAST OF THE REGION. WILL PROBABLY JUST KEEP SLIGHT CHANCE POPS FOR NOW. NOT MUCH IMPROVEMENT WITH TEMPERATURES WEDNESDAY WITH TEMPS ABOUT 5-10 DEGREES BELOW NORMAL THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A LARGE SURFACE HIGH WILL BRING CHILLY CONDITIONS MID WEEK. THEN BY LATE WEEK THERE WILL BE A RETURN OF SOUTHERLY SURFACE WINDS ON THE BACKSIDE OF HIGH PRESSURE WILL TAKE TEMPERATURES BACK TO NORMAL. HIGHS WILL PUSH BACK UP INTO THE UPPER 40S AND LOWER 50S TOWARD THE END OF THE PERIOD. DRY CONDITIONS THROUGH SATURDAY NIGHT..THEN A CHANCE OF SHOWERS AHEAD OF NEXT SYSTEM ON SUNDAY IN WEST. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THIS EVENING...WITH THE POSSIBILITY OF MVFR RESTRICTIONS DEVELOPING SOUTH OF PITTSBURGH LATE TONIGHT AS LIGHT SNOW MOVES INTO THE AREA. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... SNOW SHOWERS WILL PASS THROUGH THE REGION IN THE SOUTH AND EAST EARLY TUESDAY MORNING THROUGH LATE AFTERNOON. EXPECT IFR TO MVFR CONDITIONS IN SOUTHERN AND EASTERN TERMINALS DURING THIS TIME WHILE THE REMAINING TERMINALS SHOULD REMAIN VFR. VFR CONDITIONS WILL RETURN FOR THE REST OF THE WEEK ONCE LOW PRESSURE SYSTEM MOVES EASTWARD. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR MDZ001. OH...NONE. PA...NONE. WV...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 1 PM EST TUESDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1048 AM EST MON NOV 26 2012 .SYNOPSIS... A BROAD AREA OF HIGH PRESSURE WILL ALLOW FOR A DRY START TO THE WEEK. A WEAK SURFACE LOW WILL MOVE FROM GULF STATES INTO THE MID-ATLANTIC TONIGHT INTO TUESDAY...WITH SOME ACCUMULATING SNOW SOUTHEAST OF PITTSBURGH FOR THE COMMUTE TUESDAY MORNING. HIGH PRESSURE BUILDING IN FROM THE WEST WILL THEN ALLOW FOR A MOSTLY DRY REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... 15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO INCREASE POPS AND SNOW ACCUMULATION AMOUNTS FOR THE RIDGES OF WV/MD. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A ZONAL FLOW. A WEAK ELONGATED VORT LOBE IS SLIDING ACROSS THE SOUTHERN GREAT LAKES. WITH THE WEAK NATURE OF THIS FEATURE...THERE ARE ONLY MID DECK CLOUDS IN ITS ASSOCIATION. AT THE SURFACE...LOCALLY THE REGION IS UNDER A BROAD AREA OF HIGH PRESSURE BETWEEN HIGHS CENTERED ACROSS THE NORTHERN PLAINS AND THE SOUTHEAST. UPSTREAM...A 1010MB LOW IS DEVELOPING ACROSS TEXAS. A FRONTAL BOUNDARY EXTENDS NORTHEAST OF THIS FEATURE INTO KY/TN. WEAK HIGH PRESSURE WILL REMAIN IN CONTROL TODAY WITH CLOUD COVERAGE LIMITED TO SOME MID DECK AS THE AFOREMENTIONED H5 VORT SLIDES NORTHEAST OF THE AREA. FOR TEMPS...RECENT TRENDS...ABUNDANT SUNSHINE THIS MORNING...ALONG WITH LAMP GUIDANCE HAVE LED TO TEMPS BEING ADJUSTED UP A DEGREE ACROSS THE AREA AND 2-3 DEGREES SOUTH OF I-70. HIGHS TODAY WILL RANGE FROM THE UPPER 30S NORTH OF I-80 TO THE UPPER 40S ACROSS THE LOWLANDS SOUTH OF I-70. TONIGHT INTO TUESDAY...THE SURFACE LOW ACROSS TEXAS WILL TRACK ACROSS THE GULF STATES INTO THE SOUTHERN APPALACHIANS BY 12Z TUESDAY AND QUICKLY LIFT INTO THE MID-ATLANTIC BY 18Z. 700MB OMEGA SUPPORTS FORCING MOVING INTO NORTH-CENTRAL WV AND THE SOUTHEAST RIDGES BY 06Z WITH THE WEAK INVERTED TROUGH ASSOCIATED WITH THE LOW AND OVERRUNNING AHEAD OF THE LOW. FORCING APPEARS SUFFICIENT FOR AROUND 0.25-0.35 QPF SOUTHEAST OF PITTSBURGH WITH THIS SYSTEM BETWEEN AROUND 03Z AND 15Z TUESDAY. MODEL THICKNESSES AND SOUNDINGS SUPPORT THAT THERMAL PROFILE WILL BE COLD ENOUGH FOR PRECIP TO BE ALL SNOW WITH THIS SYSTEM. WITH THIS IN MIND...BELIEVE SLIGHT ELEVATION ENHANCEMENT ALONG WITH 10:1-12:1 SNOW-TO-LIQUID RATIOS WILL CONTRIBUTE TO MAKE THIS AN ADVISORY SNOWFALL EVENT. IN ADDITION...THE TIMING OF THIS EVENT...AROUND THE MORNING COMMUTE...WILL INCREASE THE IMPACTS OF THIS SNOWFALL. FOR SNOW AMOUNTS...FORECAST IS ON THE HIGH END OF GUIDANCE...TAKING INTO ACCOUNT THE BETTER RESOLUTION OF THE 12KM NAM AND HOW ITS RESOLVING ENHANCED PRECIP ACROSS THE RIDGES. WITH THAT IN MIND...ANTICIPATE 2 TO 5 INCHES ACROSS PRESTON...TUCKER...AND GARRETT COUNTIES WITH THE HIGHEST AMOUNTS ALONG THE HIGHEST RIDGES. GENERALLY 1 TO 2 INCHES OF SNOW IS FORECAST FOR A TIER OF COUNTIES TO THE WEST...WHICH WOULD BE A SUFFICIENT AMOUNT OF SNOW TO ALSO IMPACT THE MORNING COMMUTE...ALBEIT WITH SUB-ADVISORY LEVELS. OTHERWISE...ACROSS THE PITTSBURGH METRO AND TO THE NORTH AND WEST...EXPECT LITTLE OR NO ACCUMULATION. PRECIP WITH THIS SYSTEM LOOKS TO SHIFT EAST OF THE AREA BY 18Z TUESDAY WITH A DRY REMAINDER OF THE DAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST. FOR TEMPS...LAMP GUIDANCE SEEMS REASONABLE SOUTHEAST OF PITTSBURGH WITH LOWS IN THE UPPER 20S TO LOWER 30S. FURTHER NORTH...WENT A FEW DEGREES BELOW GUIDANCE FOR LOWS IN THE MID 20S. CLOUD COVERAGE WILL CONTRIBUTE TO LIMIT TEMPS FOR HIGHS ON TUESDAY...GENERALLY IN THE MID TO UPPER 30S ACROSS THE AREA. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL BUILD INTO THE UPPER OHIO VALLEY WITH A DRY AND COLD TUESDAY NIGHT EXPECTED. A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS ONTARIO AND THE EASTERN GREAT LAKES ON WEDNESDAY. SYNOPTIC MOISTURE WILL MAKE ITS WAY INTO THE NORTHERN COUNTIES...BUT THIS MAY ONLY PROVIDE CLOUDS AND NO PRECIPITATION. IT REMAINS TO BE SEEN WHETHER WINDS WILL ALIGN TO PROVIDE LAKE MOISTURE BEFORE THE SHORTWAVE PUSHES EAST OF THE REGION. WILL PROBABLY JUST KEEP SLIGHT CHANCE POPS FOR NOW. NOT MUCH IMPROVEMENT WITH TEMPERATURES WEDNESDAY WITH TEMPS ABOUT 5-10 DEGREES BELOW NORMAL THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A LARGE SURFACE HIGH WILL BRING CHILLY CONDITIONS MID WEEK. THEN BY LATE WEEK THERE WILL BE A RETURN OF SOUTHERLY SURFACE WINDS ON THE BACKSIDE OF HIGH PRESSURE WILL TAKE TEMPERATURES BACK TO NORMAL. HIGHS WILL PUSH BACK UP INTO THE UPPER 40S AND LOWER 50S TOWARD THE END OF THE PERIOD. DRY CONDITIONS THROUGH SATURDAY NIGHT..THEN A CHANCE OF SHOWERS AHEAD OF NEXT SYSTEM ON SUNDAY IN WEST. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL KEEP VFR CONDITIONS THROUGH THIS EVENING...WITH THE POSSIBILITY OF MVFR RESTRICTIONS DEVELOPING SOUTH OF PITTSBURGH LATE TONIGHT AS LIGHT SNOW MOVES INTO THE AREA. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... SNOW SHOWERS WILL PASS THROUGH THE REGION IN THE SOUTH AND EAST EARLY TUESDAY MORNING THROUGH LATE AFTERNOON. EXPECT IFR TO MVFR CONDITIONS IN SOUTHERN AND EASTERN TERMINALS DURING THIS TIME WHILE THE REMAINING TERMINALS SHOULD REMAIN VFR. VFR CONDITIONS WILL RETURN FOR THE REST OF THE WEEK ONCE LOW PRESSURE SYSTEM MOVES EASTWARD. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...WOODRUM NEAR TERM...WOODRUM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EST MON NOV 26 2012 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 421 PM EST MON NOV 26 2012 MAIN ITEM OF CONCERN FOR THE START OF THE SHORT TERM WILL BE THE ONGOING LES...MAINLY OVER THE EASTERN CWA. HIGH PRESSURE RIDGE MOVING OVER THE CWA FROM HIGH OVER THE LOWER GREAT LAKES AND AHEAD OF A LOW APPROACHING FROM NEAR LAKE WINNIPEG WILL ALLOW THE WINDS TO BACK TO THE WEST THIS EVENING AND THEN WEST-SOUTHWEST DURING THE OVERNIGHT HOURS. THIS...COMBINED WITH LOWERING INVERSION HEIGHTS THIS EVENING WILL CONTINUE TO DIMINISH LES INTENSITY THROUGH THE EVENING OVER THE WEST. THINK THE AREA THAT WILL HANG ONTO IT THE LONGEST WILL BE OVER NORTHERN HOUGHTON COUNTY...UNDER INCREASED CONVERGENCE WITH THE BACKING WINDS. AS THE WINDS CONTINUE TO BACK TO THE SOUTH WEST...HIGH RES MODELS INDICATING A STRONGER BAND OF LAKE EFFECT SNOW BECOMING PARALLEL TO OR RIGHT OVER THE WESTERN KEWEENAW SHORELINE FROM THE UPPER ENTRANCE TO EAGLE HARBOR. WITH THE LOWER INVERSION AND DRIER AIR ALOFT INITIALLY...DON/T THINK THE INTENSITY WILL BE TOO STRONG...BUT COULD SEE A BRIEF INCREASE LATE TONIGHT AS DEEPER MOISTURE ARRIVES AHEAD OF THE APPROACHING LOW/FRONT. IF THE SOUTHWEST FLOW WASN/T PRODUCING AS MUCH WAA...H850 TEMPS RISING TO -9C BY 12Z TUESDAY AND LOWERING LOW LEVEL LAPSE RATES...WOULD BE CONCERNED ABOUT HIGHER SNOW AMOUNTS. LAKE EFFECT SNOW PARAMETER ALSO SHOWING THIS QUICK UPTICK IN ACTIVITY LATE TONIGHT AND THEN QUICKLY DIMINISHING TOWARDS DAYBREAK WITH THE WAA. AS FOR THE EAST...EXPECT NORTHWEST WIND LES...AIDED BY THE CONVERGENCE OVER THE EASTERN LAKE FROM A SURFACE TROUGH...TO CONTINUE OVER THE NEXT SEVERAL HOURS IN THE MUNISING TO GRAND MARAIS AREA. MODELS SEEM TO BE STRUGGLING WITH THE STRENGTH OF THE TROUGH...BUT THE RAP HAS HAD A DECENT HANDLE ON IT THROUGH THE DAY...DUE TO BETTER INITIALIZATION OF LOW LEVEL WINDS...AND WILL FOLLOW THAT FOR THE NEAR TERM. RADAR ESTIMATES OF 1-2 IN/HR SNOW IN THAT AREA OVER THE LAST COUPLE OF HOURS AND WILL KEEP THE LES WARNING GOING THROUGH 03Z TONIGHT. AFTER 03Z...H950-900 WINDS BACK TO THE WEST-NORTHWEST AND START PUSH THE STRONGER BAND OFF TO THE EAST. THIS SHOULD ACCELERATE THROUGH THE OVERNIGHT HOURS...AS WINDS BECOME WESTERLY AND THEN WEST-SOUTHWEST LATE. STILL EXPECT THERE TO BE SOME HEAVIER SNOW IN THIS BAND...BUT THE TRANSIENT NATURE WILL KEEP ACCUMULATIONS LIMITED AFTER 03Z. COULD NEED A BRIEF ADVISORY ON THE BACK SIDE OF THE WARNING FOR ALGER AND NORTHERN SCHOOLCRAFT...BUT WITH IT QUICKLY WINDING DOWN AND SPS THIS EVENING SHOULD COVER IT. WITH THE SNOW AMOUNTS SHOWN ON RADAR...HAVE BUMPED UP SNOW AMOUNTS THROUGH 3Z...WITH 5-7IN BETWEEN MUNISING AND SHINGLETON. WEAK LOW PRESSURE SYSTEM CURRENTLY TO THE WEST OF LAKE WINNIPEG AND ASSOCIATED COLD FRONT WILL SWEEP ACROSS WESTERN LAKE SUPERIOR LATE TUESDAY MORNING THROUGH TUESDAY EVENING. WITH THE SOUTHWEST FLOW IN PLACE ON TUESDAY MORNING...EXPECT THE MAIN SNOW TO BE OCCURRING OVER WESTERN/NORTHERN LAKE SUPERIOR AND POTENTIALLY RIGHT ALONG THE NORTHWEST SHORELINE OF KEWEENAW COUNTY. LOW-MID CLOUDS SHOULD BE PUSHING INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY MORNING...SO EXPECT MUCH OF THE AREA TO BE CLOUDY...ALTHOUGH THERE COULD BE SOME BREAKS OVER THE EAST DEPENDING ON HOW THICK THE 6-10KFT DECK IS. WITH DECENT H850 WAA MOVING THROUGH COULD ALSO SEE SOME ISOLATED/SCATTERED SNOW SHOWERS MOVING OVER THE WESTERN LAKE AND FAR WESTERN UPPER MI DURING THE MORNING. THEN...WITH THE ARRIVAL OF THE WEAK SHORTWAVE...ASSOCIATED HEIGHT FALLS...AND H850-500 Q-VECTOR CONV AND WAA OVER THE WESTERN HALF OF THE CWA IN THE AFTERNOON...THINK THERE WILL BE ENOUGH TO PRODUCE SCATTERED SNOW SHOWERS OVER THE WESTERN/CENTRAL CWA DURING THE AFTERNOON. THE STRONGEST SNOW SHOWERS WILL LIKELY BE OVER THE KEWEENAW PENINSULA...WHERE WINDS WILL VEER DURING THE AFTERNOON AND PUSH ANY LES BAND OVER THE WESTERN LAKE ONSHORE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 421 PM EST MON NOV 26 2012 TUESDAY NIGHT...THE MODELS WERE IN REASONABLE AGREEMENT WITH THE CLIPPER SHORTWAVE TROUGH INTO WRN UPPER MI AT 00Z/WED. AS THE SHRTWV AND ASSOCIATED COLD FRONT MOVES THROUGH...WINDS WILL VEER FROM SW TO NW. WITH FAVORABLE 850-700 MB MOISTURE...850 MB TEMPS AROUND -11C...AND LOW LEVEL CONVERGENCE NEAR THE FRONT ..EXPECT A PERIOD OF MODERATE TO HEAVY LAKE EFFECT SNOW TO MOVE THROUGH THE WEST IN THE EVENING AND THEN FOCUS MAINLY OVER THE NE CWA LATE WED NIGHT. SNOWFALL AMOUNTS MAY APPROACH ADVY CRITERIA OF AROUND 4 INCHES...IN HIGHER TERRAIN OVER THE WEST SOUTH OF HOUGHTON AND OVER EASTERN ALGER INTO NRN LUCE COUNTIES. WEDNESDAY...THE LES SHOULD DIMINISH FROM WEST TO EAST AS A SFC RIDGE BUILDS INTO THE AREA WITH BACKING WINDS AND DROPPING INVERSION HEIGHTS. THE BEST CHANCE FOR SIGNIFICANT ACCUMULATIONS WILL REMAIN OVER THE FAR NE CWA IN THE MORNING (NE LUCE COUNTY) WHERE THE HIGHER RES MODELS INDICATE POTENTIAL FOR GREATEST LOW LEVEL CONV WITH 300-310 FLOW. WED NIGHT INTO THU...AS A SHRTWV MOVES THROUGH NRN ONTARIO AND HIGH PRES BUILDS FROM NRN ALBERTA AND SASK INTO NRN ONTARIO...ANOTHER WEAK COLD FRONT WILL DROP THROUGH THE NRN GREAT LAKES. BEHIND THE FRONT...WINDS ARE EXPECTED TO VEER TO THE NORTHEAST. WITH ONLY SHALLOW COLD AIR MASS AND DRY ACYC FLOW INTO THE AREA...ONLY SLIGHT CHANCE POPS WERE INCLUDED FOR -SHSN LATE WED NIGHT INTO THU MORNING OVER MAINLY N CNTRL UPPER MI. FRIDAY THROUGH MONDAY...THE MODELS WERE IN GENERAL AGREEMENT WITH A TRANSITION TO A MORE ZONAL PATTERN BRINGING MILD PACIFIC AIR INTO THE REGION. AS WAA AND MOISTURE ADVECTION INCREASES FRIDAY...ENOUGH COLD AIR IS EXPECTED TO LINGER SO THAT MAINLY -SN WOULD BE EXPECTED WITH ANY LIGHT PCPN. THE ECMWF WAS STRONGER/SLOWER WITH A SHORTWAVE RESULTING IN A MORE PRONOUNCED WARM/MOIST SURGE SATURDAY COMPARED TO THE GFS/GEM. FOLLOWING THE RAIN CHANCES SAT...MOIST/MILD AIR IS EXPECTED TO LINGER INTO EARLY NEXT WEEK WHEN ADDITIONAL RAIN CHANCES ARE POSSIBLE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1246 PM EST MON NOV 26 2012 EXPECT NORTHWEST WIND LAKE EFFECT TO GRADUALLY SHIFT THIS AFTERNOON AND TONIGHT AS THE WINDS BACK TO THE WEST THIS EVENING AND THEN SOUTHWEST OVERNIGHT AS A SURFACE RIDGE MOVES THROUGH. THIS SHOULD LEAD TO CONDITIONS QUICKLY IMPROVING TO VFR AT KIWD THIS AFTN. WITH THE WIND BEING FAVORABLE AT KCMX THROUGH MUCH OF THE PERIOD...HAVE LEFT MVFR VISIBILITY/CEILINGS THROUGH THE PERIOD...ALTHOUGH CONDITIONS COULD BRIEFLY BE HIGHER/LOWER AS THE LES BANDS MOVE THROUGH. WILL CONTINUE MENTION OF IFR VISIBILITIES LATE THIS EVENING AND THROUGH HALF OF THE OVERNIGHT AS WINDS TURN TO THE SOUTHWEST AND THERE IS AN AREA OF INCREASED CONVERGENCE MOVING THROUGH. AN APPROACHING LOW PRESSURE SYSTEM AND WEAK FRONT WILL APPROACH WESTERN LAKE SUPERIOR TONIGHT AND TUESDAY MORNING...LEADING TO INCREASING MID CLOUDS AND LIKELY PUSH THE SNOW SHOWERS SOUTHEAST TOWARDS KCMX TOWARDS LATE MORNING. KSAW WILL BE IN AN UNFAVORABLE WIND DIRECTION AND EXPECT THEM TO BE AT VFR THROUGH THE PERIOD. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 421 PM EST MON NOV 26 2012 WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO GALES ARE EXPECTED. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ006- 085. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ002-003-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLB AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1247 PM EST MON NOV 26 2012 .UPDATE... ISSUED AT 1007 AM EST MON NOV 26 2012 MAIN QUESTION FOR THE MORNING UPDATE IS THE HANDLING OF THE LAKE EFFECT SNOW ADVISORY FOR MARQUETTE COUNTY. STRONGER BAND THAT WAS SETUP OVER BIG BAY THIS MORNING HAS DISSIPATED AS LOW LEVEL WINDS HAVE SHIFTED MORE OUT OF THE WEST AND AT TIMES SOUTHWEST. THIS HAS WEAKENED THE ENTIRE BAND...EVEN TOWARDS MUNISING WHERE VISIBILITIES WERE LESS THAN A HALF MILE BASED OFF WEBCAMS. WITH THIS BAND DIMINISHING...ATTENTION TURNS TO STRONGER BAND LOCATED ALONG THE SURFACE TROUGH OVER EASTERN LAKE SUPERIOR...MAINLY FROM THE TIP OF THE KEWEENAW TO WHITEFISH POINT. WINDS HAVE SHIFTED TO THE NORTH BEHIND THIS TROUGH AND HAVE BEEN AIDING A SOUTHWARD PUSH OVER THE LAST COUPLE OF HOURS. QUESTION WITH THIS BAND IS WHERE IT WILL BECOME FOCUSED LATER THIS AFTERNOON AND INTO TONIGHT. LATEST RUC RUN AND 00Z NCEP WRF-ARW/NMM FOCUSES IT OVER ALGER AND NORTHERN SCHOOLCRAFT...WHILE OUR LOCAL 12Z WRF...12Z NAM...AND 06Z NCEP WRF-ARW/NMM HOLDS IT OVER LUCE COUNTY WITH A WEAKER NORTHERLY PUSH OVER EASTERN LAKE SUPERIOR. BOTH CASES LIMIT THE WESTWARD EXTENT DUE TO THE LOWERING INVERSIONS AND DRIER AIR FROM A SURFACE RIDGE MOVING OVER WESTERN UPPER MICHIGAN THIS AFTERNOON. SINCE THERE IS ALREADY AN ADVISORY OUT FOR LUCE...WILL KEEP IT AS IS AT THIS POINT...BUT WILL MONITOR FOR POTENTIAL UPGRADE TO WARNING IF BAND HOLDS UP IN LUCE COUNTY. AS FOR MARQUETTE...THINKING OF DROPPING THE ADVISORY SINCE THE MAIN BAND THAT IT WAS ISSUED FOR HAS DISSIPATED. THERE IS SOME CONCERN FOR N-S BANDS DEVELOPING NEAR THE TIP OF THE KEWEENAW...BUT THE GENERAL MORE NORTHWESTERLY FLOW AHEAD OF THE TROUGH SHOULD PUSH IT EAST OF BIG BAY AND MUCH OF MARQUETTE COUNTY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 431 AM EST MON NOV 26 2012 WNW FLOW ALOFT SEEN ON WV LOOP AND 00Z RAOBS. ONE SHORTWAVE WORKED THROUGH THE AREA SUNDAY EVENING AND ANOTHER WEAKER WAVE IS POISED TO MOVE ACROSS LATE THIS MORNING/EARLY AFTN. BASED ON RADAR AND SFC OBS APPEARS THAT OUTSIDE OF STRONGEST CONVERGENCE ZONE OVER EASTERN LK SUPERIOR CLOSER TO SFC LOW/TROUGH...AIRMASS IS ONLY CONDITIONALLY UNSTABLE FOR STRONG LK EFFECT SNOW /LES/ DESPITE AMPLE OVER-WATER INSTABILITY /SFC-H85 DELTA T/S OVER 20C AND LAKE EQUILIBRIUM LEVELS OVR 7KFT/. IN THE NEXT FEW HOURS...H85 COLD FRONT OVER NORTHWEST LK SUPERIOR WILL MAKE ITS WAY ACROSS WESTERN LK SUPERIOR. EXPECT CYCLONIC WNW-NW FLOW TO AFFECT WESTERN LK SUPERIOR AND INTO WESTERN CWA RESULTING IN THE WEAKLY ORGANIZED LK EFFECT WHICH IS PRESENT TO SPIKE IN INTENSITY. ALREADY SEEING SIGNS OF THIS AT KIWD WITH VSBY BRIEFLY DOWN TO 1 1/4SM AND MODERATE SNOW NOTED PER WEBCAM FROM IRONWOOD. PERIOD FOR PICKUP IN SNOW LOOKS TO LAST THROUGH THE MORNING BEFORE INVERSIONS FALL BLO 5KFT AND DRY AIR IN BLYR /SFC DWPNTS BLO 10F UPSTREAM/ COMBINE TO DECREASE SNOW INTENSITY. SNOW AMOUNTS FOR THE MORNING OF 3-5 INCHES SEEM LIKELY IN ADVY AREA. GIVEN POTENTIAL OF HEAVIER SNOW BANDS LINGERING THROUGH MIDDAY...DELAYED EXPIRATION OF ADVY TIL 18Z. OVER THE EASTERN CWA...CURRENT LES TRENDS AND VERY CONSISTENT OUTPUT FROM HIGHER RESOLUTION GUIDANCE LAST DAY OR TWO SUPPORT EXPANSION OF HEAVY LES FROM MUNISING TO GRAND MARAIS TO PINE STUMP JUNCTION THROUGH THE DAY. ARRIVAL OF H85 TROUGH SHOULD RESULT IN SFC TROUGH OVER EASTERN LK SUPERIOR SINKING TOWARD THE SHORELINE THIS MORNING. NET RESULT IS STRONG AREA OF SFC CONVERGENCE SETTING UP/PERSISTING OVER SOUTHEAST LK SUPERIOR INTO ALGER/NORTHERN SCHOOLCRAFT COUNTIES THROUGH THE AFTN. UNLIKE THE WESTERN CWA...CONDITIONS OVER EASTERN LK SUPERIOR WILL NOT BE NEAR AS HOSTILE TO LES THIS AFTN AS INVERSION/LAKE EQL REMAINS TOWARD 8KFT/10KFT THROUGH MUCH OF THE DAY...PLACING BULK OF LES CONVECTIVE LAYER WITHIN DGZ/HIGHER SNOW RATIOS. CONVERGENCE ALREADY STRONGER IN THIS AREA CURRENTLY SO NO REASON TO BELIEVE LES WILL NOT INTENSIFY TODAY. CURRENT LES WARNING LOOKS ON TRACK. EXPECT TOTAL DAYTIME SNOWFALL UP TO 8 INCHES...CENTERED ON MUNISING AND MELSTRAND. ALREADY SEEING CONVERGENCE BAND OF ENHANCE SNOW SETUP IN THESE AREAS CURRENTLY. DID THINK ABOUT GOING WITH WARNING FOR LUCE AS WELL...BUT SINCE MAJORITY OF SNOW EARLY THIS MORNING HAS STAYED MAINLY OFFSHORE...EXPECTED SNOW TOTALS THROUGH THE DAY SUPPORT KEEPING THE ADVY. UPGRADE COULD BE POSSIBLE DEPENDING ON LES TRENDS THIS MORNING. FARTHER SOUTH...THOUGHT ABOUT AN ADVY FOR THE DAY OVER SOUTHERN SCHOOLCRAFT COUNTY. SOME HIGHER RESOULTION MODELS...ESPECIALLY LOCAL WRF AND NCEP WRF-ARW INDICATE DOMINANT BAND AROUND MUNISING MAY MAKE IT INTO GOOD PART OF SOUTHERN SCHOOLCRAFT. AT THIS POINT...LOW-LEVEL CONVERGENCE IS EXPECTED TO BE SHARP BUT PRETTY FOCUSED INTO MAINLY ALGER COUNTY...SO DECIDED AGAINST ADVY. AWAY FROM LES TODAY...COLD AIR ADVECTION THROUGH DAY SHOULD LEAD TO PRETTY STEADY TEMPS OVER CWA...ESPECIALLY GIVEN FAIRLY RESILIENT CLOUD COVER. FAR WEST PROBABLY STAYS LOCKED INTO THE TEENS WITH READINGS FALLING THIS AFTN SLIGHTLY. TEMPS IN THE LOW-MID 20S COVER IT ELSEWHERE. NO BIG CHANGE TO PREVIOUS THINKING FOR LES TRENDS TONIGHT. HIGH PRESSURE NEARING FROM THE PLAINS RESULTS IN SFC-H85 WINDS TO STEADILY BACK WNW IN THE EVENING AND MORE TO THE WSW OVERNIGHT. HEADLINES CONTINUE OVER NORTHEAST CWA THROUGH EVENING...WITH A FEW MORE INCHES OF SNOW LIKELY. AWAY FROM LES...BACKING WINDS SHOULD ALLOW SKIES TO CLEAR IN THE EVENING WITH POSSIBLY THE COLDEST NIGHT OF THE LATE FALL ON TAP. EXPECT TEMPS TO DROP QUICKLY INTO THE LOWER TEENS AND SINGLE DIGITS OVERNIGHT. ANOTHER CLIPPER SYSTEM NEARING IN WNW FLOW SPREADS A MID CLOUD DECK ACROSS MUCH OF CWA AFTER MIDNIGHT. TEMPS LIKELY WILL BECOME STEADY BY THAT TIME SO TEMPS TONIGHT WILL NOT END UP AS COLD AS THEY WOULD BE OTHERWISE WITH SIMILAR SETUP TO START THE NIGHT. STILL...MAY SEE MIDDLE SINGLE DIGITS IN THE COLDER SPOTS OF THE INTERIOR CENTRAL IF SKIES STAY CLEAR LONGER. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 431 AM EST MON NOV 26 2012 A SHORTWAVE TROUGH/SFC TROUGH AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE CWA FROM LATE TUE AFTERNOON INTO WED NIGHT...WITH DRY SFC RIDGING MOVING INTO THE WRN CWA BY 18Z WED. LOW LEVEL FLOW WILL INITIALLY BE FROM THE WSW WITH 850MB TEMPS OF -8C TO -14C FROM W TO E RESPECTIVELY. LES SHOULD BE SITTING PRIMARILY OVER THE WRN LAKE AND NRN KEWEENAW PENINSULA...WITH SOME LES OCCASIONALLY DRIFTING OVER OTHER LAND AREAS OR WRN UPPER MI. LOW LEVEL WINDS TURN MORE WLY BY 00Z WED THEN NW BY 06Z WED AS 850MB TEMPS DROP TO AROUND -15C. BL MOISTURE DECREASES PRETTY QUICKLY FROM W TO E LATE WED NIGHT INTO WED AS THE RIDGE MOVES IN...DIMINISHING /OR AT LEAST SIGNIFICANTLY WEAKENING/ LES. THE ONE PLACE WHERE LES MAY HANG ON ALL DAY WED IS OVER THE FAR NE U.P. SINCE ANOTHER SHORTWAVE MOVES INTO NE LAKE SUPERIOR LATE WED INTO WED NIGHT. LOOKS LIKE ALL BUT THE SOUTH CENTRAL CWA WILL SEE SNOW FROM THE SHORTWAVE/LES...WITH THE TYPICAL NW WIND SNOWBELTS SEEING THE MOST SNOW. AT THIS POINT...THE HIGHER TERRAIN OF THE NW CWA LOOKS TO SEE 3-5 INCHES OF SNOW...AND THE ERN CWA 2-4 INCHES. NW LOW LEVEL WINDS WILL VEER AROUND TO THE SE BY FRI NIGHT AS A SFC HIGH PASSES JUST NE OF THE CWA...BUT CONDITIONS WILL NOT BE FAVORABLE FOR ANY SIGNIFICANT LES WITH THE MORE N/NE WINDS DURING THE TRANSITION TO SE WINDS. GENERAL TREND TOWARD WARMER TEMPS LOOKS IN ORDER FOR FRI INTO THE WEEKEND. MODELS GENERALLY AGREE THAT LOW PRESSURE AT THE SFC WILL DOMINATE THE NE CONUS INTO THE PLAINS STATES...AND A SHORTWAVE/WAA REGIME THAT WOULD BRING SNOW TO THE AREA FRI. CONFIDENCE DECREASES SIGNIFICANTLY SAT AND SUN AS MODEL AGREEMENT DECREASES AND MODEL RUN TO RUN CONTINUITY IS POOR. USED A CONSENSUS OF GUIDANCE FOR MUCH OF THIS PERIOD GIVEN THE DECREASED CONFIDENCE IN ANY ONE MODEL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1246 PM EST MON NOV 26 2012 EXPECT NORTHWEST WIND LAKE EFFECT TO GRADUALLY SHIFT THIS AFTERNOON AND TONIGHT AS THE WINDS BACK TO THE WEST THIS EVENING AND THEN SOUTHWEST OVERNIGHT AS A SURFACE RIDGE MOVES THROUGH. THIS SHOULD LEAD TO CONDITIONS QUICKLY IMPROVING TO VFR AT KIWD THIS AFTN. WITH THE WIND BEING FAVORABLE AT KCMX THROUGH MUCH OF THE PERIOD...HAVE LEFT MVFR VISIBILITY/CEILINGS THROUGH THE PERIOD...ALTHOUGH CONDITIONS COULD BRIEFLY BE HIGHER/LOWER AS THE LES BANDS MOVE THROUGH. WILL CONTINUE MENTION OF IFR VISIBILITIES LATE THIS EVENING AND THROUGH HALF OF THE OVERNIGHT AS WINDS TURN TO THE SOUTHWEST AND THERE IS AN AREA OF INCREASED CONVERGENCE MOVING THROUGH. AN APPROACHING LOW PRESSURE SYSTEM AND WEAK FRONT WILL APPROACH WESTERN LAKE SUPERIOR TONIGHT AND TUESDAY MORNING...LEADING TO INCREASING MID CLOUDS AND LIKELY PUSH THE SNOW SHOWERS SOUTHEAST TOWARDS KCMX TOWARDS LATE MORNING. KSAW WILL BE IN AN UNFAVORABLE WIND DIRECTION AND EXPECT THEM TO BE AT VFR THROUGH THE PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 431 AM EST MON NOV 26 2012 WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO GALES ARE EXPECTED. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ006- 085. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST /4 PM CST/ THIS AFTERNOON FOR MIZ002-003-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLA LONG TERM...TITUS AVIATION...SRF MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1008 AM EST MON NOV 26 2012 .UPDATE... ISSUED AT 1007 AM EST MON NOV 26 2012 MAIN QUESTION FOR THE MORNING UPDATE IS THE HANDLING OF THE LAKE EFFECT SNOW ADVISORY FOR MARQUETTE COUNTY. STRONGER BAND THAT WAS SETUP OVER BIG BAY THIS MORNING HAS DISSIPATED AS LOW LEVEL WINDS HAVE SHIFTED MORE OUT OF THE WEST AND AT TIMES SOUTHWEST. THIS HAS WEAKENED THE ENTIRE BAND...EVEN TOWARDS MUNISING WHERE VISIBILITIES WERE LESS THAN A HALF MILE BASED OFF WEBCAMS. WITH THIS BAND DIMINISHING...ATTENTION TURNS TO STRONGER BAND LOCATED ALONG THE SURFACE TROUGH OVER EASTERN LAKE SUPERIOR...MAINLY FROM THE TIP OF THE KEWEENAW TO WHITEFISH POINT. WINDS HAVE SHIFTED TO THE NORTH BEHIND THIS TROUGH AND HAVE BEEN AIDING A SOUTHWARD PUSH OVER THE LAST COUPLE OF HOURS. QUESTION WITH THIS BAND IS WHERE IT WILL BECOME FOCUSED LATER THIS AFTERNOON AND INTO TONIGHT. LATEST RUC RUN AND 00Z NCEP WRF-ARW/NMM FOCUSES IT OVER ALGER AND NORTHERN SCHOOLCRAFT...WHILE OUR LOCAL 12Z WRF...12Z NAM...AND 06Z NCEP WRF-ARW/NMM HOLDS IT OVER LUCE COUNTY WITH A WEAKER NORTHERLY PUSH OVER EASTERN LAKE SUPERIOR. BOTH CASES LIMIT THE WESTWARD EXTENT DUE TO THE LOWERING INVERSIONS AND DRIER AIR FROM A SURFACE RIDGE MOVING OVER WESTERN UPPER MICHIGAN THIS AFTERNOON. SINCE THERE IS ALREADY AN ADVISORY OUT FOR LUCE...WILL KEEP IT AS IS AT THIS POINT...BUT WILL MONITOR FOR POTENTIAL UPGRADE TO WARNING IF BAND HOLDS UP IN LUCE COUNTY. AS FOR MARQUETTE...THINKING OF DROPPING THE ADVISORY SINCE THE MAIN BAND THAT IT WAS ISSUED FOR HAS DISSIPATED. THERE IS SOME CONCERN FOR N-S BANDS DEVELOPING NEAR THE TIP OF THE KEWEENAW...BUT THE GENERAL MORE NORTHWESTERLY FLOW AHEAD OF THE TROUGH SHOULD PUSH IT EAST OF BIG BAY AND MUCH OF MARQUETTE COUNTY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 431 AM EST MON NOV 26 2012 WNW FLOW ALOFT SEEN ON WV LOOP AND 00Z RAOBS. ONE SHORTWAVE WORKED THROUGH THE AREA SUNDAY EVENING AND ANOTHER WEAKER WAVE IS POISED TO MOVE ACROSS LATE THIS MORNING/EARLY AFTN. BASED ON RADAR AND SFC OBS APPEARS THAT OUTSIDE OF STRONGEST CONVERGENCE ZONE OVER EASTERN LK SUPERIOR CLOSER TO SFC LOW/TROUGH...AIRMASS IS ONLY CONDITIONALLY UNSTABLE FOR STRONG LK EFFECT SNOW /LES/ DESPITE AMPLE OVER-WATER INSTABILITY /SFC-H85 DELTA T/S OVER 20C AND LAKE EQUILIBRIUM LEVELS OVR 7KFT/. IN THE NEXT FEW HOURS...H85 COLD FRONT OVER NORTHWEST LK SUPERIOR WILL MAKE ITS WAY ACROSS WESTERN LK SUPERIOR. EXPECT CYCLONIC WNW-NW FLOW TO AFFECT WESTERN LK SUPERIOR AND INTO WESTERN CWA RESULTING IN THE WEAKLY ORGANIZED LK EFFECT WHICH IS PRESENT TO SPIKE IN INTENSITY. ALREADY SEEING SIGNS OF THIS AT KIWD WITH VSBY BRIEFLY DOWN TO 1 1/4SM AND MODERATE SNOW NOTED PER WEBCAM FROM IRONWOOD. PERIOD FOR PICKUP IN SNOW LOOKS TO LAST THROUGH THE MORNING BEFORE INVERSIONS FALL BLO 5KFT AND DRY AIR IN BLYR /SFC DWPNTS BLO 10F UPSTREAM/ COMBINE TO DECREASE SNOW INTENSITY. SNOW AMOUNTS FOR THE MORNING OF 3-5 INCHES SEEM LIKELY IN ADVY AREA. GIVEN POTENTIAL OF HEAVIER SNOW BANDS LINGERING THROUGH MIDDAY...DELAYED EXPIRATION OF ADVY TIL 18Z. OVER THE EASTERN CWA...CURRENT LES TRENDS AND VERY CONSISTENT OUTPUT FROM HIGHER RESOLUTION GUIDANCE LAST DAY OR TWO SUPPORT EXPANSION OF HEAVY LES FROM MUNISING TO GRAND MARAIS TO PINE STUMP JUNCTION THROUGH THE DAY. ARRIVAL OF H85 TROUGH SHOULD RESULT IN SFC TROUGH OVER EASTERN LK SUPERIOR SINKING TOWARD THE SHORELINE THIS MORNING. NET RESULT IS STRONG AREA OF SFC CONVERGENCE SETTING UP/PERSISTING OVER SOUTHEAST LK SUPERIOR INTO ALGER/NORTHERN SCHOOLCRAFT COUNTIES THROUGH THE AFTN. UNLIKE THE WESTERN CWA...CONDITIONS OVER EASTERN LK SUPERIOR WILL NOT BE NEAR AS HOSTILE TO LES THIS AFTN AS INVERSION/LAKE EQL REMAINS TOWARD 8KFT/10KFT THROUGH MUCH OF THE DAY...PLACING BULK OF LES CONVECTIVE LAYER WITHIN DGZ/HIGHER SNOW RATIOS. CONVERGENCE ALREADY STRONGER IN THIS AREA CURRENTLY SO NO REASON TO BELIEVE LES WILL NOT INTENSIFY TODAY. CURRENT LES WARNING LOOKS ON TRACK. EXPECT TOTAL DAYTIME SNOWFALL UP TO 8 INCHES...CENTERED ON MUNISING AND MELSTRAND. ALREADY SEEING CONVERGENCE BAND OF ENHANCE SNOW SETUP IN THESE AREAS CURRENTLY. DID THINK ABOUT GOING WITH WARNING FOR LUCE AS WELL...BUT SINCE MAJORITY OF SNOW EARLY THIS MORNING HAS STAYED MAINLY OFFSHORE...EXPECTED SNOW TOTALS THROUGH THE DAY SUPPORT KEEPING THE ADVY. UPGRADE COULD BE POSSIBLE DEPENDING ON LES TRENDS THIS MORNING. FARTHER SOUTH...THOUGHT ABOUT AN ADVY FOR THE DAY OVER SOUTHERN SCHOOLCRAFT COUNTY. SOME HIGHER RESOULTION MODELS...ESPECIALLY LOCAL WRF AND NCEP WRF-ARW INDICATE DOMINANT BAND AROUND MUNISING MAY MAKE IT INTO GOOD PART OF SOUTHERN SCHOOLCRAFT. AT THIS POINT...LOW-LEVEL CONVERGENCE IS EXPECTED TO BE SHARP BUT PRETTY FOCUSED INTO MAINLY ALGER COUNTY...SO DECIDED AGAINST ADVY. AWAY FROM LES TODAY...COLD AIR ADVECTION THROUGH DAY SHOULD LEAD TO PRETTY STEADY TEMPS OVER CWA...ESPECIALLY GIVEN FAIRLY RESILIENT CLOUD COVER. FAR WEST PROBABLY STAYS LOCKED INTO THE TEENS WITH READINGS FALLING THIS AFTN SLIGHTLY. TEMPS IN THE LOW-MID 20S COVER IT ELSEWHERE. NO BIG CHANGE TO PREVIOUS THINKING FOR LES TRENDS TONIGHT. HIGH PRESSURE NEARING FROM THE PLAINS RESULTS IN SFC-H85 WINDS TO STEADILY BACK WNW IN THE EVENING AND MORE TO THE WSW OVERNIGHT. HEADLINES CONTINUE OVER NORTHEAST CWA THROUGH EVENING...WITH A FEW MORE INCHES OF SNOW LIKELY. AWAY FROM LES...BACKING WINDS SHOULD ALLOW SKIES TO CLEAR IN THE EVENING WITH POSSIBLY THE COLDEST NIGHT OF THE LATE FALL ON TAP. EXPECT TEMPS TO DROP QUICKLY INTO THE LOWER TEENS AND SINGLE DIGITS OVERNIGHT. ANOTHER CLIPPER SYSTEM NEARING IN WNW FLOW SPREADS A MID CLOUD DECK ACROSS MUCH OF CWA AFTER MIDNIGHT. TEMPS LIKELY WILL BECOME STEADY BY THAT TIME SO TEMPS TONIGHT WILL NOT END UP AS COLD AS THEY WOULD BE OTHERWISE WITH SIMILAR SETUP TO START THE NIGHT. STILL...MAY SEE MIDDLE SINGLE DIGITS IN THE COLDER SPOTS OF THE INTERIOR CENTRAL IF SKIES STAY CLEAR LONGER. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 431 AM EST MON NOV 26 2012 A SHORTWAVE TROUGH/SFC TROUGH AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE CWA FROM LATE TUE AFTERNOON INTO WED NIGHT...WITH DRY SFC RIDGING MOVING INTO THE WRN CWA BY 18Z WED. LOW LEVEL FLOW WILL INITIALLY BE FROM THE WSW WITH 850MB TEMPS OF -8C TO -14C FROM W TO E RESPECTIVELY. LES SHOULD BE SITTING PRIMARILY OVER THE WRN LAKE AND NRN KEWEENAW PENINSULA...WITH SOME LES OCCASIONALLY DRIFTING OVER OTHER LAND AREAS OR WRN UPPER MI. LOW LEVEL WINDS TURN MORE WLY BY 00Z WED THEN NW BY 06Z WED AS 850MB TEMPS DROP TO AROUND -15C. BL MOISTURE DECREASES PRETTY QUICKLY FROM W TO E LATE WED NIGHT INTO WED AS THE RIDGE MOVES IN...DIMINISHING /OR AT LEAST SIGNIFICANTLY WEAKENING/ LES. THE ONE PLACE WHERE LES MAY HANG ON ALL DAY WED IS OVER THE FAR NE U.P. SINCE ANOTHER SHORTWAVE MOVES INTO NE LAKE SUPERIOR LATE WED INTO WED NIGHT. LOOKS LIKE ALL BUT THE SOUTH CENTRAL CWA WILL SEE SNOW FROM THE SHORTWAVE/LES...WITH THE TYPICAL NW WIND SNOWBELTS SEEING THE MOST SNOW. AT THIS POINT...THE HIGHER TERRAIN OF THE NW CWA LOOKS TO SEE 3-5 INCHES OF SNOW...AND THE ERN CWA 2-4 INCHES. NW LOW LEVEL WINDS WILL VEER AROUND TO THE SE BY FRI NIGHT AS A SFC HIGH PASSES JUST NE OF THE CWA...BUT CONDITIONS WILL NOT BE FAVORABLE FOR ANY SIGNIFICANT LES WITH THE MORE N/NE WINDS DURING THE TRANSITION TO SE WINDS. GENERAL TREND TOWARD WARMER TEMPS LOOKS IN ORDER FOR FRI INTO THE WEEKEND. MODELS GENERALLY AGREE THAT LOW PRESSURE AT THE SFC WILL DOMINATE THE NE CONUS INTO THE PLAINS STATES...AND A SHORTWAVE/WAA REGIME THAT WOULD BRING SNOW TO THE AREA FRI. CONFIDENCE DECREASES SIGNIFICANTLY SAT AND SUN AS MODEL AGREEMENT DECREASES AND MODEL RUN TO RUN CONTINUITY IS POOR. USED A CONSENSUS OF GUIDANCE FOR MUCH OF THIS PERIOD GIVEN THE DECREASED CONFIDENCE IN ANY ONE MODEL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 643 AM EST MON NOV 26 2012 COLDER AIR MOVING INTO THE UPPER LAKES WILL CONTINUE TO GENERATE LAKE EFFECT -SHSN THRU TODAY...MAINLY AT KIWD AND KCMX DUE TO WNW/NW FLOW. AT KCMX...IFR TO MVFR CONDITIONS SHOULD PREVAIL TODAY. BACKING WINDS THIS EVENING AND THE RESULTING CONVERGENCE ZONE MAY BRING A PERIOD OF HEAVIER SNOW/IFR CONDITIONS THIS EVENING. AT KIWD... ENHANCED LOW-LEVEL CONVERGENCE SHOULD LEAD TO OCNL HEAVIER SNOW/IFR CONDITIONS THIS MORNING. OTHERWISE...MVFR CONDITIONS SHOULD GENERALLY PREVAIL. AS WINDS BACK THIS EVENING...CONDITIONS WILL IMPROVE TO VFR AS LAKE EFFECT SHSN END. AT KSAW...DOWNSLOPE NATURE OF WNW WINDS SHOULD LEAD TO GENERALLY VFR CONDITIONS WITH FLURRIES/-SHSN AT TIMES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 431 AM EST MON NOV 26 2012 WITH GENERALLY WEAK CLIPPER SYSTEMS BEING THE MAIN WIND PRODUCERS OVER THE NEXT FEW DAYS...WINDS OF 20 TO 30 KTS WILL BE COMMON BUT NO GALES ARE EXPECTED. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ006- 085. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ005. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR MIZ002-003-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...JLA LONG TERM...TITUS AVIATION...ROLFSON/JLA MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST MON NOV 26 2012 .UPDATE... ISSUED AT 1010 PM EST SUN NOV 25 2012 OVERALL...GOING FCST APPEARS TO BE IN GOOD SHAPE. UPSTREAM 00Z KINL SOUNDING SHOWED MOIST LOW LEVELS UP TO AROUND 800MB...BUT WITH SHARP INVERSION AT 850MB. 850MB TEMP WAS -20C WHICH WILL MEAN THAT AS THE NIGHT WEARS ON...THE DGZ WILL INTERSECT A GOOD PORTION OF THE CONVECTIVE LAYER...LEADING TO HIGHER SNOW-TO-WATER RATIOS. THERE ARE A COUPLE OF FCST CONCERNS. FIRST...CONVERGENCE OVER WRN LAKE SUPERIOR HAS LED TO MORE PERSISTENT LES OVER NE ONTONAGON COUNTY ACROSS CNTRL/SRN HOUGHTON COUNTY INTO BARAGA COUNTY. OPTED TO INCLUDE SRN HOUGHTON COUNTY IN LES ADVY WITH FOCUS ALONG M-38. CONSIDERED ADDING BARAGA COUNTY...BUT SO FAR...WHILE LES HAS BEEN MORE PERSISTENT...REFLECTIVITIES AREN`T EXCEEDING 28DBZ...AND THE POCKETS OF HEAVIER SNOW HAVE BEEN TRANSIENT. RAISED 12HR SNOW ACCUMULATIONS TO 2-4 INCHES (UNDER ADVY CRITERIA FOR LES). FARTHER S...NOT MUCH HAS BEEN GOING ON ACROSS THE REST OF ONTONAGON/GOGEBIC COUNTIES. WITH WINDS VEERING A LITTLE MORE TO THE NW OVER WRN LAKE SUPERIOR...LES SHOULD PICK UP IN THIS AREA DURING THE NIGHT. LAND BREEZE COMPONENT TO WIND SHOULD LEAD TO ENHANCED CONVERGENCE/MORE DOMINANT LES INTO THE AREA BTWN KIWD AND THE PORCUPINE MTNS LATER IN THE NIGHT. AS HAS BEEN THE CASE THIS EVENING...THE HEAVIEST SNOW WILL CONTINUE TO BE FOCUSED OVER THE NE FCST AREA WHERE LAKE INDUCED TROFFING AND LONGER FETCH WILL LEAD TO HEAVIER SNOW. BUMPED UP SNOW ACCUMULATIONS BY A COUPLE OF INCHES OVER LUCE COUNTY GIVEN THE PERSISTENCE OF HEAVIER LES THIS EVENING. COULD BE CLOSE TO WARNING AMOUNTS OVER NRN PORTIONS OF THE COUNTY. STILL EXPECT HEAVIEST LES TO ORGANIZE LATE TONIGHT THRU MON AFTN AS SHARPENING SFC TROF DRIFTS S OVER ERN LAKE SUPERIOR. HIGH RES GUIDANCE STILL POINTS TOWARD ROUGHLY THE E HALF OF ALGER COUNTY INTO NRN SCHOOLCRAFT FOR GREATEST SNOW TOTALS AS SFC TROF WILL TEND TO HANG UP IN THAT AREA MON. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 428 PM EST SUN NOV 25 2012 WV IMAGERY AND RUC ANALYSIS INDICATED WNW MID/UPPER LEVEL FLOW THROUGH THE NRN CONUS. A SHORTWAVE TROUGH EXTENDED FROM NRN ONTARIO (NEAR CYGQ) INTO NRN WI. A WEAKER UPSTREAM SHRTWV WAS LOCATED OVER SW MANITOBA. AT THE SFC...LOW PRES WAS LOCATED JUST NORTHEAST OF LAKE SUPERIOR RESULTING IN WNW LOW LEVEL WINDS. CYCLONIC FLOW AND ABUNDANT 850-700 MB MOISTURE IN THE WAKE OF THE LOW ALONG WITH 850 MB TEMPS IN THE -11C TO -14C RANGE SUPPORTED AN INCREASE IN LES BAND INTENSITY. THE STRONGEST BANDS WERE LOCATED NEAR HOUGHTON AND INTO THE ERN CWA JUST TO THE EAST OF MUNISING. MAIN FCST CONCERNS ARE LES TRENDS. EXPECT LES TO CONTINUE FOR LOCATIONS FAVORED BY A 290-310 FLOW...INCLUDING MOST OF THE WRN CWA AND LOCATIONS FROM MUNISING EASTWARD. THE HIGH RES MODELS IN AGREEMENT SHOWING A GRADUAL VEERING TREND THIS EVENING WHICH SHOULD HELP TO KEEP THE BANDS FOR IMPACTING NARROW AREAS FOR AN EXTENDED PERIOD OF TIME. THIS SHOULD ALSO RESULT IN DECREASING LES INTENSITY INTO THE KEWEENAW WITH A LES FAVORABLE NW FETCH. THE HIGH RES MODELS WERE ALSO CONSISTENT IN SHOWING A MORE PRONOUNCED LOW LEVEL CONV ZONE AIDED BY LAKE INDUCED TROUGHING OVER ERN LAKE SUPERIOR. THIS SHOULD PROVIDE THE FOCUS FOR THE HEAVIES LES LATE TONIGHT INTO MONDAY AFTERNOON FOR EASTER ALGER AND NORTHWEST SCHOOLCRAFT COUNTIES. INVERSION HEIGHTS IN THE 5K TO 7K FOOT RANGE...GREATEST EAST...ALONG WITH A DEEP PORTION OF THE CONVECTIVE CLOUDS IN THE DENDRITIC GROWTH ZONE SHOULD KEEP SNOW/WATER RATIOS IN THE HIGHER SIDE...AT OR ABOVE 20/1. OVERALL SNOWFALL AMOUNTS IN THE 6 TO 12 INCH RANGE STILL LOOK POSSIBLE FOR SOME LOCATIONS IN ALGER/NSCHOOLCRAFT ZONES WHILE 3 TO 7 INCH AMOUNTS ARE MORE LIKELY OVER THE WEST...GREATEST IN THE HIGHER TERRAIN BTWN HOUGHTON AND BERGLAND. WITH INVERSION HEIGHTS BEGIN LOWERING FROM WEST TO EAST MONDAY PREVIOUS FCST TIMING WHICH ENDS THE LES ADVY OVER THE WEST AT 10 AM LOOKS ON TRACK. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 428 PM EST SUN NOV 25 2012 MON NGT...AS A HI PRES RDG AXIS EXTENDING NEWD FM THE ACYC CENTER IN THE CENTRAL PLAINS APRCHS...THE LLVL FLOW WL SHIFT STEADILY TO A MORE WSW DIRECTION. WITH THIS BACKING FLOW...SOME HEAVIER SHSN MIGHT IMPACT THE KEWEENAW FOR A TIME...BUT LIMITED RESIDENCE TIME WITH STEADILY SHIFTING WINDS AS WELL AS LOWERING INVRN BASE/WARMING H85 TEMPS SHOULD LIMIT OVERALL ACCUMS. OVER THE E...LLVL CNVGC/LES INTENSITY MIGHT SHARPEN FOR A TIME WITH BACKING LARGER SCALE FLOW/LAND BREEZE ENHANCED BY NOCTURNAL COOLING OVER THE CENTRAL CWA...BUT LES BANDS SHOULD SHIFT OFFSHORE BY 12Z TUE. ALTHOUGH SOME HEAVIER LES MAY LINGER NEAR THE SHORE FM GRAND MARAIS TO WHITEFISH POINT LONGER THAN THE 03Z EXPIRATION TIME OF THE GOING LES WARNING FOR ALGER COUNTY...DID NOT MAKE ANY CHANGES TO THE WARNING NOW TO AVOID POTENTIAL VERIFICATION PENALTY. ALTHOUGH THE BACKING FLOW WL ADVECT MORE UNMODIFIED COLD AIR INTO THE CWA...INCRSG WAD CLD IN ADVANCE OF NEXT CLIPPER DISTURBANCE DIGGING SEWD TOWARD THE UPR LKS WL TEND TO LIMIT THE DIURNAL TEMP FALL SOMEWHAT. TUE...COLD FNT ASSOCIATED WITH THIS INCOMING CLIPPER SHRTWV/SFC LO MOVING THRU NW ONTARIO IS PROGGED TO REACH THE WRN CWA BY 00Z WED. PCPN IN ADVANCE OF THIS FNT WL BE LIMITED BY LLVL DRY AIR/ABSENCE OF SGNFT MSTR INFLOW...BUT SUSPECT A PERIOD OF HEAVIER SHSN MIGHT IMPACT THE W LATER IN THE DAY WITH SOME ENHANCEMENT OFF LK SUP IN LLVL W FLOW WITH H85 TEMPS ARND -10C UNDER DPVA/DEEP LYR QVECTOR CNVGC. NO MORE THAN CHC POPS WL BE APPROPRIATE OVER THE REST OF THE CWA EXCEPT FOR THE E...WHERE SOME MOISTENING OF THE LLVLS IN SW FLOW OFF LK MI WITH SUFFICIENTLY COLD AIR TO GENERATE LES MIGHT RESULT IN SOME SHSN. GOING FCST DRY WX FOR THE FAR SCENTRAL SEEMS ON TRACK. TUE NGT/WED...THE COLD FNT IS FCST TO SWING THRU THE UPR LKS AND USHER IN A VERY CHILLY AIRMASS WITH H85 TEMPS AS LO AS -16C BY 12Z WED. DESPITE THIS INCOMING CHILL...LES IN THE WAKE OF THE FROPA WL BE STUNTED SOMEWHAT BY FAIRLY QUICK TRANSITION TO GENERAL ACYC FLOW UNDER SHARP NVA/DEEP LYR QVECTOR DVGC/SUBSIDENCE THAT IS FCST TO LOWER INVRN BASE OVER THE W TO BTWN 3-4K FT AGL BY 12Z WED. DESPITE THESE NEGATIVES...OPTED TO GO WITH LIKELY POPS IN THE FAVORED NW WIND SN BELTS...ESPECIALLY OVER THE E WITH LONGER FETCH AND SOME LK NIPIGON PRE MOISTENING...GIVEN SUFFICIENT COLD AIR INFLUX/LK-H85 DELTA T APRCHG 20C. ON WED...THE LES IN THE NW WIND SN BELTS WL DIMINISH WITH ARRIVAL OF SFC RDG AXIS/LOWERING INVRN BASE TO 2-3K FT AGL/BACKING LLVL WINDS TOWARD THE W-SW. EXTENDED...LONGER RANGE MODELS REMAIN VERY CONSISTENT SHOWING A MAJOR PATTERN CHG LATER THIS COMING WEEK THAT WL FEATURE A ZONAL FLOW OF UNSEASONABLY WARM PACIFIC AIR NEXT WEEKEND AS TROF IN ERN CANADA LIFTS TO THE NE. ON THU...COLD CNDN HI PRES OVER ONTARIO UNDER WNW FLOW ALF WL STILL BE DOMINATING THE UPR LKS...BUT STRENGTHENING ISENTROPIC ASCENT ASSOCIATED WITH OVERRUNNING OF THE RETREATING ARCTIC AIRMASS WL RESULT IN INCRSG CLDS TO THE NE OF WARM FGEN IN THE NRN PLAINS TO LOWER LKS. AFTER THU...SOME VARIANCE CREEPS INTO THE MODEL BLEND. RECENT ECMWF RUNS HAVE BEEN VERY CONSISTENT INDICATING SOME -SN MAY DVLP ON THU NGT AND FRI AS THE WARM FNT MOVES TO THE N. THE ECMWF INDICATES PCPN MAY EVEN TRANSITION TO SOME -FZDZ AS DEEPER MSTR SHIFTS TO THE N AS LINGERING NEAR SFC COLD AIR BECOMES SHALLOWER WITH LOWERING WARM FRONTAL INVRN HGT. ON THE OTHER HAND...THE MAJORITY OF RECENT GFS RUNS SHOW THE WARM FNT REMAINING FARTHER S AS A WAVE OF LO PRES ASSOCIATED WITH A STRONGER SHRTWV RIPPLING THRU THE UPR MIDWEST RUNS W-E ALONG THIS BNDRY. GIVEN THE LARGER SCALE TRENDS TOWARD RISING HGTS IN THE GRT LKS AND CONSISTENCY OF THE ECMWF...WHICH IS ALSO PREFERRED BY NCEP...TENDED TO USE THE ECMWF AS A GUIDE FOR PTYPE DURING THIS TIME. BULK OF MODELS SHOW ANOTHER SHRTWV WL APRCH ON SAT. IF THE ECMWF IS CORRECT...PCPN SHOULD BE MAINLY RA. ONLY MARITIME POLAR AIR WL FOLLOW THIS DISTURBANCE FOR SUN UNDER THE ZONAL FLOW ALF...SO ANY LES ON SUN SHOULD BE MINIMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1225 AM EST MON NOV 26 2012 COLDER AIR MOVING INTO THE UPPER LAKES WILL CONTINUE TO GENERATE LAKE EFFECT -SHSN THRU TODAY...MAINLY AT KIWD AND KCMX DUE TO WNW/NW FLOW. AT KCMX...MVFR CONDITIONS SHOULD GENERALLY PREVAIL. BACKING WINDS THIS EVENING AND THE RESULTING CONVERGENCE ZONE MAY BRING A PERIOD OF HEAVIER SNOW/IFR CONDITIONS THIS EVENING. AT KIWD... ENHANCED LOW-LEVEL CONVERGENCE SHOULD LEAD TO OCNL HEAVIER SNOW/IFR CONDITIONS OVERNIGHT. OTHERWISE...MVFR CONDITIONS SHOULD GENERALLY PREVAIL. AS WINDS BACK THIS EVENING...CONDITIONS WILL IMPROVE TO VFR AS LAKE EFFECT SHSN END. AT KSAW...DOWNSLOPE NATURE OF WNW WINDS SHOULD LEAD TO GENERALLY VFR CONDITIONS WITH FLURRIES/-SHSN AT TIMES. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 428 PM EST SUN NOV 25 2012 EXPECT NW WINDS TO 30 KTS TONIGHT AS LOW PRESSURE JUST NORTHEAST OF LAKE SUPERIOR MOVES QUICKLY OFF TO THE EAST. THERE MAY ALSO BE A FEW GALE GUSTS TO 35 KTS TONIGHT OVER NORTHERN AND EASTERN PORTIONS OF LK SUPERIOR. WINDS WILL DIMINISH TO 15 TO 25 KT MONDAY AS HIGH PRESSURE BUILDS INTO THE UPPER MS VALLEY AND THE WESTERN GREAT LAKES. AS HI PRES RIDGE MOVES THRU THE UPPER GREAT LAKES ON MON NIGHT... EXPECT DIMINISHING WINDS BACKING TO THE SW. THIS SW WIND WILL INCREASE UP TO 25 TO 30 KTS ON TUE AHEAD OF AN APPROACHING COLD FRONT. FOLLOWING THE FRONTAL PASSAGE ON LATE TUE/TUE NIGHT...PLAN ON A WIND SHIFT TO THE NW UP TO 30 KTS AS MUCH COLDER AIR MOVES OVER LAKE SUPERIOR AND ENHANCES MIXING OF THE STRONGER WINDS TO THE SURFACE. THE APPROACH OF ANOTHER HI PRES WILL BRING DIMINISHING WINDS FOR WED. WITH RELATIVELY WEAK PRES GRADIENT IN PLACE THEN FOR THU/FRI...WINDS SHOULD BE UNDER 25 KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 10 PM EST THIS EVENING FOR MIZ006- 085. LAKE EFFECT SNOW ADVISORY UNTIL 5 AM EST TUESDAY FOR MIZ007. LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR MIZ002-003-009-084. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...ROLFSON SHORT TERM...JLB LONG TERM...KC AVIATION...ROLFSON MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
139 PM CST MON NOV 26 2012 .UPDATE...LOWERED TEMPERATURES FOR TODAY AS COLD AIR ADVECTION AND SOME SNOW COVER SEEMS TO BE KEEPING TEMPERATURES DOWN MORE...DESPITE SOME SUN BREAKING OUT FROM THE NORTHWEST. ADJUSTED SOME LINGERING SNOW POSSIBILITIES CONFINED TO SOUTHEASTERN PARTS OF THE CWA THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 1143 AM CST MON NOV 26 2012/ AVIATION...18Z KGRI TAF. CIGS AND VIS WILL IMPROVE THIS AFTERNOON AS WIND SPEEDS DIMINISH WITH SURFACE HIGH PRESSURE BUILDING IN. CEILINGS WILL ALSO SCATTER BY LATE AFTERNOON. WIND SPEED COULD BEGIN PICKING BACK UP FOR THE LAST HOUR OR TWO OF THE FORECAST DURING THE LATE MORNING ON TUESDAY AS THE PRESSURE GRADIENT INCREASES WITH AN APPROACHING COLD FRONT. PREV DISCUSSION... /ISSUED 416 AM CST MON NOV 26 2012/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT MAIN THEME: WINTER MAKES A BRIEF APPEARANCE TODAY WITH SOME MINOR ACCUMULATION N OF I-80...THEN A RAPID RECOVERY IN TEMPS TOMORROW AND CONTINUED WARMING THRU MID-WEEK. UPPER-LEVELS: LONGWAVE TROF CONTS TO ORGANIZE OVER THE E PACIFIC... DOWNSTREAM OF THE BERING SEA BLOCKING HIGH. A RIDGE WAS BUILDING ALONG THE W COAST. AS MULTIPLE SHORTWAVE TROFS ORBIT AROUND THE DEVELOPING CUT-OFF LOW /WITHIN THE LONGWAVE TROF/ THE RIDGE WILL GRADUALLY HEAD E TO THE FRONT RANGE OF THE ROCKIES BY WED NGT. BOTTOM LINE...NW FLOW THRU TUE NGT THEN BACKING TO W FLOW WED. AT 09Z A VORT MAX/SHORTWAVE TROF WAS OVER MT/WY AND DROPPING SE. IN ADVANCE OF THIS VORT MAX A BATCH -SN WAS OCCURRING WITHIN A PULSE OF QG FORCING/RRQ OF A 120 KT JET ON THE TROPOPAUSE. THE VORT MAX WILL CONT SE INTO NEB THIS MRNG. SURFACE: COLD/STRONG ARCTIC HIGH PRES WAS OVER ND WITH NE LOW-LEVEL FLOW PROVIDING AN UPSLOPE COMPONENT. THIS HIGH WILL EXPAND AND SINK SWD OVER THE CNTRL PLAINS BY THIS EVNG...THEN INTO THE LOWER MS VALLEY TUE AND THE TN VALLEY WED. 00Z RAOBS SHOW LOTS OF DRY AIR TO OVERCOME. SOME OF THE LIFT WILL GO TOWARD SATURATION WHICH COULD DELAY THE START TIME. USED RAP/NAM 925-850 MB RH OF 90% TO GUIDE OUR POPS AS THAT ISOHUME LINED UP FAIRLY WELL WITH OBSERVED -SN. AFTER A FEW FLURRIES AROUND 06Z...STEADY -SN BEGAN AT ORD AT 08Z. EXPECTATION IS THAT BATCH OF -SN WILL DROP S AND AFFECT MOST OF THE FCST AREA...THOUGH NRN KS COULD ONLY SEE FLURRIES...IF THAT. THIS SWD TREND IS SEEN VIA 00Z/06Z NAM LOW-LEVEL RH. LIFT: THE "BEST" LIFT /QG FORCING COUPLED WITH WEAK FGEN AND MODEST MID-LEVEL INSTABILITY/ OCCURS UNTIL 18Z WHEN TROF PASSES AND SUBSIDENCE TAKES OVER. OVERALL MAGNITUDE OF LIFT IS UNIMPRESSIVE AND IS MOSTLY BELOW THE DENDRITIC GROWTH ZONE /DGZ/. THIS WILL RESULT IN MOSTLY SMALLER RIMED FLAKES. SO EXPECT LOWER SNOW-LIQUID RATIOS. SNOWFALL: AS WE SEE IT NOW A HALF INCH OR LESS ALONG AND N OF I-80 WITH AROUND 1 INCH OVER PARTS OF VALLEY/SHERMAN COUNTIES AND GREELEY/HOWARD COUNTIES COULD END UP CLOSE. JUST A DUSTING FROM HWY 6 UP TO I-80. WHERE CAN THIS ACCUM FCST BREAK DOWN? VALLEY/GREELEY COUNTIES. THE 4KM NMM SNOW ALGORITHM OUTPUTS UP TO 3.5 INCHES. BELIEVE THIS IS A LOW PROBABILITY...BUT SOMETHING TO MONITOR AS WE ARE WATCHING THE THE 30 DBZ SNOWBAND DROPPING SLOWLY DUE S ON LXN RADAR /FROM CNTRL CHERRY COUNTY E TO AINSWORTH AND ONEIL/. ANW VSBY HAS AVERAGED 2 SM AND HAS BEEN AS LOW AS 1 1/2 SM. LESSER QUALITY OF DENDRITES/SMALLER FLAKE SIZES WILL PROBABLY KEEP ACCUMS BELOW ADVISORY LEVEL /3 INCHES/. IF THIS BAND HOLDS TOGETHER...WE COULD SEE 1" IN DAWSON/ BUFFALO COUNTIES. THE COBB ALGORITHM OFFERS 1.4 AT ORD FROM THE 08Z RAP AND 2.4 FROM THE 00Z NAM. HOWEVER...GIVEN ITS SNOW:LIQUID RATIOS LOOK INFLATED GIVEN WEAK VERTICAL MOTION. UNCERTAINTIES: HOW FAR S WITH THE SNOW FALL? WE COULD BE A LITTLE TOO FAR S WITH POPS FOR MEASURABLE LIQUID EQUIV. RAP/NAM SOUNDINGS HAVE A REMNANT DRY LAYER BELOW 4K FT UNTIL 16Z AT HSI. ALSO UNSURE HOW QUICKLY TO DECREASE CLOUD COVER BY 21Z. WE SEE THE CLEAR SKIES OVER NRN SD ON SATELLITE. AFTER 18Z...PCPN INTENSITY WILL DROP OFF SIGNIFICANTLY AND BY 21Z SKIES SHOULD START SEE CLEARING. MODEL DWPTS LOOK TOO LOW ONCE SNOW BEGINS. SO INCREASED DWPTS WHERE WE EXPECT SNOW TO BE FALLING TO CLOSE DWPT DEPRESSIONS. TEMPS PROBABLY GO NOWHERE OVER NEB THRU MIDDAY. AS CLOUDS START TO THIN FROM THE N IN THE AFTN...THEN WE SHOULD SEE SOME RISE. OVER NRN KS THINNER CLOUDS IN THE MRNG WILL ALLOW FOR SOME RISE WHICH PROBABLY STALLS MIDDAY IN THICKENING CLOUDS. TNGT: M/CLEAR. HIGH PRES DRIFTS S OF THE FCST AREA. WINDS TURN LIGHT OR CALM IN THE EVNG THEN DEVELOP FROM THE SW. TEMPS ARE BIAS CORRECTED BLEND OF 2M TEMPS AND THE PREVIOUS GID FCST IN AN ATTEMPT TO CAPTURE BIG RADIATORS /ODX AND LXN/. EXPECT TEENS MOST LOCATIONS EXCEPT FROM HDE-HSI-GRI WHICH WILL REMAIN IN THE LOW 20S. WITH FRESH SNOWCOVER AND WINDS EXPECTED TO GO CALM AT ORD...WOULDN`T BE SURPRISED TO SEE TEMPS END UP IN THE SINGLE DIGITS THERE! TUE: SUNNY AND BREEZY AS TEMPS RETURN TO NORMAL /43-55F/. SW WINDS GUST 20-30 MPH. TUE NGT: M/CLEAR WITH LIGHT/CALM WINDS. ANOTHER COLD NGT WITH AREAS IN VICINITY OF LEXINGTON/ORD IN THE TEENS AGAIN. USED BIAS CORRECTED GUIDANCE TO HELP WITH THESE USUAL COLD SPOTS AND THEIR ASSOCIATED TEMP CURVES...ESPECIALLY IN RAPID DROP-OFF IN THE EVNG. WED: SUNNY. A LITTLE WARMER AND LESS WIND. 46-59F WHICH IS ABOUT 5F ABOVE NORMAL. WED NGT: M/CLEAR WITH A LIGHT SW WIND. 21-32F. ORD PROBABLY GOES CALM FOR A TIME A DECOUPLES AGAIN. LONG TERM...THURSDAY THROUGH SUNDAY...AN UNSEASONABLY WARM AND DRY STRETCH OF WEATHER APPEARS TO BE ON TAP FOR THE LOCAL AREA AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE FLATTENS OUT OVER THE PLAINS AND A FAIRLY ZONAL TO SOUTHWESTERLY FLOW ESTABLISHES ITSELF ALOFT...WITH NO NOTABLE DISTURBANCES CAUGHT IN THIS FLOW TO SPEAK OF. THE 12Z RUN OF THE EC DID HINT AT A WEAK DISTURBANCE POTENTIALLY CROSSING THE LOCAL AREA DURING THE FRIDAY NIGHT/SATURDAY MORNING TIME PERIOD...BUT THE 00Z RUN NOW INDICATES A MORE DIFFUSE UPPER LEVEL DISTURBANCE...AND THE GFS STEERS THIS SAME UPPER LEVEL ENERGY WELL TO OUR NORTH. AS A RESULT...MAINTAINED DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES POTENTIALLY CLIMBING INTO THE UPPER 50S AND LOWER 60S FRIDAY THROUGH SUNDAY...WITH LOW TEMPERATURES EXPECTED TO REMAIN ABOVE FREEZING OVER THE SAME TIME PERIOD. NORMAL HIGH TEMPERATURES OVER THIS TIME FRAME GENERALLY RUN IN THE LOWER 40S AND NORMAL LOW TEMPERATURES RUN IN THE LOWER 20S. LOOKING BEYOND THE CURRENT EXTENT OF THE FORECAST...NO HINTS AT AN END TO THIS WARM A DRY PERIOD IN MODEL DATA THROUGH AT LEAST THE MIDDLE OF FOLLOWING WEEK AT THIS TIME. CLIMATE...WITH THE END OF THE YEAR NOW IN SIGHT...IF ANOTHER 2.16 INCHES OF LIQUID PRECIPITATION DOES NOT ACCUMULATE AT THE CENTRAL NEBRASKA REGIONAL AIRPORT IN GRAND ISLAND...2012 STANDS TO BE THE DRIEST FULL YEAR ON RECORD SINCE 1896...WHEN THE FIRST FULL YEAR OF RECORD KEEPING BEGAN IN THE GRAND ISLAND AREA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE/AVIATION...HEINLEIN SHORT TERM...HALBLAUB LONG TERM...ROSSI
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1209 PM CST MON NOV 26 2012 .UPDATE... THE AREA OF SNOW HAS PROGRESSED EAST OF THE LOCAL AREA...WITH ONLY SOME FLURRIES ONGOING AT 18Z ACROSS PARTS OF LINCOLN AND CUSTER COUNTIES. THEREFORE HAVE ALLOWED THE WINTER WEATHER ADVISORY TO EXPIRE. DID REMOVE CHANCES FOR ACCUMULATING SNOW THIS AFTERNOON AS WELL. OTHERWISE...REMAINDER OF FORECAST IS ON TRACK AS CLOUDS SLOWLY BREAK UP AND MOVE OUT OF THE AREA AND TEMPERATURES SEE VERY LITTLE WARMING THROUGH THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 1147 AM CST MON NOV 26 2012/ AVIATION.../FOR THE 26.18Z TAF ISSUANCE/ IMPROVING SKY CONDITIONS ARE EXPECTED OVER THE NEXT 6 HOURS FOR ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. AT 17Z...HIGH PRESSURE WAS CENTERED OVER SOUTH CENTRAL SOUTH DAKOTA...WITH A DISSIPATING DECK OF STRATUS JUST ON ITS WESTWARD EDGE. THIS WAS IMPACTING KVTN AND KANW...DOWN TOWARDS KBBW. EXPECT THIS TO TO CONTINUE TO DIMINISH IN THE NEXT SEVERAL HOURS...SO DO IMPROVE THE KVTN FORECAST TO VFR BY 20Z. FURTHER SOUTH...SNOW HAS ENDED...BUT LOWER /MVFR/ CEILINGS REMAINED. THIS CLOUD COVER IS EXPECTED TO BECOME MORE COMPACT AND LIFT AS THE AFTERNOON PROGRESSES. HERE TOO...EXPECT VFR CONDITIONS BY MID AFTERNOON. FOR TONIGHT AS THE HIGH DRIFTS EAST...SOUTHWEST FLOW WILL SET UP...WITH WINDS BLOWING UP TO 10 MPH INTO THE MORNING HOURS ON TUESDAY. ONLY SOME ADDITIONAL HIGH CLOUDS /AOA 20K FEET/ ARE EXPECTED INTO TUESDAY. PREV DISCUSSION... /ISSUED 732 AM CST MON NOV 26 2012/ UPDATE... THE FRONTOGENETICALLY FORCED BAND OF LIGHT TO MODERATES CONTINUES TO MOVE SOUTH THIS MORNING PROMPTING THE ADDITION OF ANOTHER TIER OF COUNTIES TO THE WINTER WEATHER ADVISORY. NONE OF THE MODELS SEEM TO HAVE A GOOD HANDLE ON THE SOUTHWARD PROGRESSION OF THE SNOW BAND. GIVEN THE TIME OF DAY AND NEBRASKA DEPARTMENT OF ROADS REPORTS IT LOOKS LIKE THE SNOW BAND COULD PRODUCE HAZARDOUS TRAVEL FOR A FEW HOURS THIS MORNING ALONG HIGHWAY 92 AND ACROSS AT LEAST THE NORTHERN HALF OF CUSTER COUNTY. WHAT REMAINS TO BE DETERMINED IS THE IMPACT ON INTERSTATE 80. ONE POSITIVE WOULD BE THE EFFECT OF DAYLIGHT AND THE PREVIOUS DAYS HIGH TEMPERATURES IN THE 50S. THIS COULD CERTAINLY MINIMIZE THE TRAVEL HAZARD. PREV DISCUSSION... /ISSUED 437 AM CST MON NOV 26 2012/ UPDATE... REPORTS FROM FROM THE NEBRASKA DEPARTMENT OF ROADS AND RADAR SUGGEST SNOW WILL CONTINUE TO ACCUMULATE ON ROADWAYS THROUGH AT LEAST SUNRISE. ADDITIONAL COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY. TEMPERATURES CONTINUE TO FALL INTO THE LOWER 20S ACROSS NRN NEBRASKA SUGGESTING A HIGH PROBABILITY OF ICING ON ROADWAYS WITH ROAD SFCS LIKELY CROSSING THE FREEZING MARK. THE FRONTOGENETICALLY FORCED SNOW BAND ACROSS THE SANDHILLS IS SHOWING SIGNS OF TIGHTENING UP AS VERY COLD 700MB AIR DRIVES SOUTH AND COLLIDES WITH WARM MID LEVEL TO THE SOUTH NEAR KLBF. PREV DISCUSSION... /ISSUED 351 AM CST MON NOV 26 2012/ DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...TAYLOR AVIATION...BROOKS UPDATES...CDC/BROOKS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1147 AM CST MON NOV 26 2012 .AVIATION.../FOR THE 26.18Z TAF ISSUANCE/ IMPROVING SKY CONDITIONS ARE EXPECTED OVER THE NEXT 6 HOURS FOR ALL OF WESTERN AND NORTH CENTRAL NEBRASKA. AT 17Z...HIGH PRESSURE WAS CENTERED OVER SOUTH CENTRAL SOUTH DAKOTA...WITH A DISSIPATING DECK OF STRATUS JUST ON ITS WESTWARD EDGE. THIS WAS IMPACTING KVTN AND KANW...DOWN TOWARDS KBBW. EXPECT THIS TO TO CONTINUE TO DIMINISH IN THE NEXT SEVERAL HOURS...SO DO IMPROVE THE KVTN FORECAST TO VFR BY 20Z. FURTHER SOUTH...SNOW HAS ENDED...BUT LOWER /MVFR/ CEILINGS REMAINED. THIS CLOUD COVER IS EXPECTED TO BECOME MORE COMPACT AND LIFT AS THE AFTERNOON PROGRESSES. HERE TOO...EXPECT VFR CONDITIONS BY MID AFTERNOON. FOR TONIGHT AS THE HIGH DRIFTS EAST...SOUTHWEST FLOW WILL SET UP...WITH WINDS BLOWING UP TO 10 MPH INTO THE MORNING HOURS ON TUESDAY. ONLY SOME ADDITIONAL HIGH CLOUDS /AOA 20K FEET/ ARE EXPECTED INTO TUESDAY. && .PREV DISCUSSION... /ISSUED 732 AM CST MON NOV 26 2012/ UPDATE... THE FRONTOGENETICALLY FORCED BAND OF LIGHT TO MODERATES CONTINUES TO MOVE SOUTH THIS MORNING PROMPTING THE ADDITION OF ANOTHER TIER OF COUNTIES TO THE WINTER WEATHER ADVISORY. NONE OF THE MODELS SEEM TO HAVE A GOOD HANDLE ON THE SOUTHWARD PROGRESSION OF THE SNOW BAND. GIVEN THE TIME OF DAY AND NEBRASKA DEPARTMENT OF ROADS REPORTS IT LOOKS LIKE THE SNOW BAND COULD PRODUCE HAZARDOUS TRAVEL FOR A FEW HOURS THIS MORNING ALONG HIGHWAY 92 AND ACROSS AT LEAST THE NORTHERN HALF OF CUSTER COUNTY. WHAT REMAINS TO BE DETERMINED IS THE IMPACT ON INTERSTATE 80. ONE POSITIVE WOULD BE THE EFFECT OF DAYLIGHT AND THE PREVIOUS DAYS HIGH TEMPERATURES IN THE 50S. THIS COULD CERTAINLY MINIMIZE THE TRAVEL HAZARD. PREV DISCUSSION... /ISSUED 437 AM CST MON NOV 26 2012/ UPDATE... REPORTS FROM FROM THE NEBRASKA DEPARTMENT OF ROADS AND RADAR SUGGEST SNOW WILL CONTINUE TO ACCUMULATE ON ROADWAYS THROUGH AT LEAST SUNRISE. ADDITIONAL COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY. TEMPERATURES CONTINUE TO FALL INTO THE LOWER 20S ACROSS NRN NEBRASKA SUGGESTING A HIGH PROBABILITY OF ICING ON ROADWAYS WITH ROAD SFCS LIKELY CROSSING THE FREEZING MARK. THE FRONTOGENETICALLY FORCED SNOW BAND ACROSS THE SANDHILLS IS SHOWING SIGNS OF TIGHTENING UP AS VERY COLD 700MB AIR DRIVES SOUTH AND COLLIDES WITH WARM MID LEVEL TO THE SOUTH NEAR KLBF. PREV DISCUSSION... /ISSUED 351 AM CST MON NOV 26 2012/ DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NEZ004>006-008>010-023>028-035>038-094. && $$ SHORT TERM/EXTENDED...TAYLOR UPDATES...CDC AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1143 AM CST MON NOV 26 2012 .AVIATION...18Z KGRI TAF. CIGS AND VIS WILL IMPROVE THIS AFTERNOON AS WIND SPEEDS DIMINISH WITH SURFACE HIGH PRESSURE BUILDING IN. CEILINGS WILL ALSO SCATTER BY LATE AFTERNOON. WIND SPEED COULD BEGIN PICKING BACK UP FOR THE LAST HOUR OR TWO OF THE FORECAST DURING THE LATE MORNING ON TUESDAY AS THE PRESSURE GRADIENT INCREASES WITH AN APPROACHING COLD FRONT. && PREV DISCUSSION... /ISSUED 416 AM CST MON NOV 26 2012/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT MAIN THEME: WINTER MAKES A BRIEF APPEARANCE TODAY WITH SOME MINOR ACCUMULATION N OF I-80...THEN A RAPID RECOVERY IN TEMPS TOMORROW AND CONTINUED WARMING THRU MID-WEEK. UPPER-LEVELS: LONGWAVE TROF CONTS TO ORGANIZE OVER THE E PACIFIC... DOWNSTREAM OF THE BERING SEA BLOCKING HIGH. A RIDGE WAS BUILDING ALONG THE W COAST. AS MULTIPLE SHORTWAVE TROFS ORBIT AROUND THE DEVELOPING CUT-OFF LOW /WITHIN THE LONGWAVE TROF/ THE RIDGE WILL GRADUALLY HEAD E TO THE FRONT RANGE OF THE ROCKIES BY WED NGT. BOTTOM LINE...NW FLOW THRU TUE NGT THEN BACKING TO W FLOW WED. AT 09Z A VORT MAX/SHORTWAVE TROF WAS OVER MT/WY AND DROPPING SE. IN ADVANCE OF THIS VORT MAX A BATCH -SN WAS OCCURRING WITHIN A PULSE OF QG FORCING/RRQ OF A 120 KT JET ON THE TROPOPAUSE. THE VORT MAX WILL CONT SE INTO NEB THIS MRNG. SURFACE: COLD/STRONG ARCTIC HIGH PRES WAS OVER ND WITH NE LOW-LEVEL FLOW PROVIDING AN UPSLOPE COMPONENT. THIS HIGH WILL EXPAND AND SINK SWD OVER THE CNTRL PLAINS BY THIS EVNG...THEN INTO THE LOWER MS VALLEY TUE AND THE TN VALLEY WED. 00Z RAOBS SHOW LOTS OF DRY AIR TO OVERCOME. SOME OF THE LIFT WILL GO TOWARD SATURATION WHICH COULD DELAY THE START TIME. USED RAP/NAM 925-850 MB RH OF 90% TO GUIDE OUR POPS AS THAT ISOHUME LINED UP FAIRLY WELL WITH OBSERVED -SN. AFTER A FEW FLURRIES AROUND 06Z...STEADY -SN BEGAN AT ORD AT 08Z. EXPECTATION IS THAT BATCH OF -SN WILL DROP S AND AFFECT MOST OF THE FCST AREA...THOUGH NRN KS COULD ONLY SEE FLURRIES...IF THAT. THIS SWD TREND IS SEEN VIA 00Z/06Z NAM LOW-LEVEL RH. LIFT: THE "BEST" LIFT /QG FORCING COUPLED WITH WEAK FGEN AND MODEST MID-LEVEL INSTABILITY/ OCCURS UNTIL 18Z WHEN TROF PASSES AND SUBSIDENCE TAKES OVER. OVERALL MAGNITUDE OF LIFT IS UNIMPRESSIVE AND IS MOSTLY BELOW THE DENDRITIC GROWTH ZONE /DGZ/. THIS WILL RESULT IN MOSTLY SMALLER RIMED FLAKES. SO EXPECT LOWER SNOW-LIQUID RATIOS. SNOWFALL: AS WE SEE IT NOW A HALF INCH OR LESS ALONG AND N OF I-80 WITH AROUND 1 INCH OVER PARTS OF VALLEY/SHERMAN COUNTIES AND GREELEY/HOWARD COUNTIES COULD END UP CLOSE. JUST A DUSTING FROM HWY 6 UP TO I-80. WHERE CAN THIS ACCUM FCST BREAK DOWN? VALLEY/GREELEY COUNTIES. THE 4KM NMM SNOW ALGORITHM OUTPUTS UP TO 3.5 INCHES. BELIEVE THIS IS A LOW PROBABILITY...BUT SOMETHING TO MONITOR AS WE ARE WATCHING THE THE 30 DBZ SNOWBAND DROPPING SLOWLY DUE S ON LXN RADAR /FROM CNTRL CHERRY COUNTY E TO AINSWORTH AND ONEIL/. ANW VSBY HAS AVERAGED 2 SM AND HAS BEEN AS LOW AS 1 1/2 SM. LESSER QUALITY OF DENDRITES/SMALLER FLAKE SIZES WILL PROBABLY KEEP ACCUMS BELOW ADVISORY LEVEL /3 INCHES/. IF THIS BAND HOLDS TOGETHER...WE COULD SEE 1" IN DAWSON/ BUFFALO COUNTIES. THE COBB ALGORITHM OFFERS 1.4 AT ORD FROM THE 08Z RAP AND 2.4 FROM THE 00Z NAM. HOWEVER...GIVEN ITS SNOW:LIQUID RATIOS LOOK INFLATED GIVEN WEAK VERTICAL MOTION. UNCERTAINTIES: HOW FAR S WITH THE SNOW FALL? WE COULD BE A LITTLE TOO FAR S WITH POPS FOR MEASURABLE LIQUID EQUIV. RAP/NAM SOUNDINGS HAVE A REMNANT DRY LAYER BELOW 4K FT UNTIL 16Z AT HSI. ALSO UNSURE HOW QUICKLY TO DECREASE CLOUD COVER BY 21Z. WE SEE THE CLEAR SKIES OVER NRN SD ON SATELLITE. AFTER 18Z...PCPN INTENSITY WILL DROP OFF SIGNIFICANTLY AND BY 21Z SKIES SHOULD START SEE CLEARING. MODEL DWPTS LOOK TOO LOW ONCE SNOW BEGINS. SO INCREASED DWPTS WHERE WE EXPECT SNOW TO BE FALLING TO CLOSE DWPT DEPRESSIONS. TEMPS PROBABLY GO NOWHERE OVER NEB THRU MIDDAY. AS CLOUDS START TO THIN FROM THE N IN THE AFTN...THEN WE SHOULD SEE SOME RISE. OVER NRN KS THINNER CLOUDS IN THE MRNG WILL ALLOW FOR SOME RISE WHICH PROBABLY STALLS MIDDAY IN THICKENING CLOUDS. TNGT: M/CLEAR. HIGH PRES DRIFTS S OF THE FCST AREA. WINDS TURN LIGHT OR CALM IN THE EVNG THEN DEVELOP FROM THE SW. TEMPS ARE BIAS CORRECTED BLEND OF 2M TEMPS AND THE PREVIOUS GID FCST IN AN ATTEMPT TO CAPTURE BIG RADIATORS /ODX AND LXN/. EXPECT TEENS MOST LOCATIONS EXCEPT FROM HDE-HSI-GRI WHICH WILL REMAIN IN THE LOW 20S. WITH FRESH SNOWCOVER AND WINDS EXPECTED TO GO CALM AT ORD...WOULDN`T BE SURPRISED TO SEE TEMPS END UP IN THE SINGLE DIGITS THERE! TUE: SUNNY AND BREEZY AS TEMPS RETURN TO NORMAL /43-55F/. SW WINDS GUST 20-30 MPH. TUE NGT: M/CLEAR WITH LIGHT/CALM WINDS. ANOTHER COLD NGT WITH AREAS IN VICINITY OF LEXINGTON/ORD IN THE TEENS AGAIN. USED BIAS CORRECTED GUIDANCE TO HELP WITH THESE USUAL COLD SPOTS AND THEIR ASSOCIATED TEMP CURVES...ESPECIALLY IN RAPID DROP-OFF IN THE EVNG. WED: SUNNY. A LITTLE WARMER AND LESS WIND. 46-59F WHICH IS ABOUT 5F ABOVE NORMAL. WED NGT: M/CLEAR WITH A LIGHT SW WIND. 21-32F. ORD PROBABLY GOES CALM FOR A TIME A DECOUPLES AGAIN. LONG TERM...THURSDAY THROUGH SUNDAY...AN UNSEASONABLY WARM AND DRY STRETCH OF WEATHER APPEARS TO BE ON TAP FOR THE LOCAL AREA AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE FLATTENS OUT OVER THE PLAINS AND A FAIRLY ZONAL TO SOUTHWESTERLY FLOW ESTABLISHES ITSELF ALOFT...WITH NO NOTABLE DISTURBANCES CAUGHT IN THIS FLOW TO SPEAK OF. THE 12Z RUN OF THE EC DID HINT AT A WEAK DISTURBANCE POTENTIALLY CROSSING THE LOCAL AREA DURING THE FRIDAY NIGHT/SATURDAY MORNING TIME PERIOD...BUT THE 00Z RUN NOW INDICATES A MORE DIFFUSE UPPER LEVEL DISTURBANCE...AND THE GFS STEERS THIS SAME UPPER LEVEL ENERGY WELL TO OUR NORTH. AS A RESULT...MAINTAINED DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES POTENTIALLY CLIMBING INTO THE UPPER 50S AND LOWER 60S FRIDAY THROUGH SUNDAY...WITH LOW TEMPERATURES EXPECTED TO REMAIN ABOVE FREEZING OVER THE SAME TIME PERIOD. NORMAL HIGH TEMPERATURES OVER THIS TIME FRAME GENERALLY RUN IN THE LOWER 40S AND NORMAL LOW TEMPERATURES RUN IN THE LOWER 20S. LOOKING BEYOND THE CURRENT EXTENT OF THE FORECAST...NO HINTS AT AN END TO THIS WARM A DRY PERIOD IN MODEL DATA THROUGH AT LEAST THE MIDDLE OF FOLLOWING WEEK AT THIS TIME. CLIMATE...WITH THE END OF THE YEAR NOW IN SIGHT...IF ANOTHER 2.16 INCHES OF LIQUID PRECIPITATION DOES NOT ACCUMULATE AT THE CENTRAL NEBRASKA REGIONAL AIRPORT IN GRAND ISLAND...2012 STANDS TO BE THE DRIEST FULL YEAR ON RECORD SINCE 1896...WHEN THE FIRST FULL YEAR OF RECORD KEEPING BEGAN IN THE GRAND ISLAND AREA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ AVIATION...HEINLEIN SHORT TERM...HALBLAUB LONG TERM...ROSSI
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
732 AM CST MON NOV 26 2012 .UPDATE... THE FRONTOGENETICALLY FORCED BAND OF LIGHT TO MODERATES CONTINUES TO MOVE SOUTH THIS MORNING PROMPTING THE ADDITION OF ANOTHER TIER OF COUNTIES TO THE WINTER WEATHER ADVISORY. NONE OF THE MODELS SEEM TO HAVE A GOOD HANDLE ON THE SOUTHWARD PROGRESSION OF THE SNOW BAND. GIVEN THE TIME OF DAY AND NEBRASKA DEPARTMENT OF ROADS REPORTS IT LOOKS LIKE THE SNOW BAND COULD PRODUCE HAZARDOUS TRAVEL FOR A FEW HOURS THIS MORNING ALONG HIGHWAY 92 AND ACROSS AT LEAST THE NORTHERN HALF OF CUSTER COUNTY. WHAT REMAINS TO BE DETERMINED IS THE IMPACT ON INTERSTATE 80. ONE POSITIVE WOULD BE THE EFFECT OF DAYLIGHT AND THE PREVIOUS DAYS HIGH TEMPERATURES IN THE 50S. THIS COULD CERTAINLY MINIMIZE THE TRAVEL HAZARD. && .PREV DISCUSSION... /ISSUED 529 AM CST MON NOV 26 2012/ UPDATE... AVIATION... IFR IS EXPECTED THROUGH ROUGHLY 16-18Z THIS AM AS THE SNOW AND LOW CIGS GRADUALLY WEAKEN. NOTE THE SNOW ARRIVAL AT KLBF IS BASED ON THE CURRENT RADAR TRENDS WHICH COULD CHANGE AT ANY TIME AS AN UPPER LEVEL KICKER ACROSS NERN WYOMING THIS MORNING APPROACHES WHICH WOULD CAUSE THE SNOW BAND TO FALL APART. ALSO THE SNOW ENDING TIME AT KVTN IS ESSENTIALLY A MODEL GUESS AS THE RADAR IS OVERSHOOTING THE SNOW AT THAT LOCATION SUGGESTING THE SNOW WILL END AT ANY TIME. VFR COULD BE WIDESPREAD BY 18Z AND CONTINUE OVERNIGHT AS HIGH PRESSURE BUILDS INTO THE REGION. PREV DISCUSSION... /ISSUED 437 AM CST MON NOV 26 2012/ UPDATE... REPORTS FROM FROM THE NEBRASKA DEPARTMENT OF ROADS AND RADAR SUGGEST SNOW WILL CONTINUE TO ACCUMULATE ON ROADWAYS THROUGH AT LEAST SUNRISE. ADDITIONAL COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY. TEMPERATURES CONTINUE TO FALL INTO THE LOWER 20S ACROSS NRN NEBRASKA SUGGESTING A HIGH PROBABILITY OF ICING ON ROADWAYS WITH ROAD SFCS LIKELY CROSSING THE FREEZING MARK. THE FRONTOGENETICALLY FORCED SNOW BAND ACROSS THE SANDHILLS IS SHOWING SIGNS OF TIGHTENING UP AS VERY COLD 700MB AIR DRIVES SOUTH AND COLLIDES WITH WARM MID LEVEL TO THE SOUTH NEAR KLBF. PREV DISCUSSION... /ISSUED 351 AM CST MON NOV 26 2012/ DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. AVIATION...EXPECTING MAINLY MVFR CONDITIONS WITH 5SM -SN AT KVTN THROUGH 12Z.VFR CONDITIONS SHOULD PREVAIL BY 15Z. SNOWFALL AREA TO DEVELOP SOUTH OVERNIGHT INTO MONDAY MORNING AS A SHORTWAVE TROUGH MOVES ACROSS EASTERN WYOMING INTO THE NEBRASKA PANHANDLE. CURRENT VFR CONDITIONS AT KLBF SHOULD TRANSITION TO MVFR CEILINGS BETWEEN 09Z-12Z WITH P6SM -SN WITH TEMPO OF 2SM -SN AFTER 12Z. MVFR CONDITIONS COULD PERSIST INTO THE AFTERNOON IF SYSTEM SLOWS OR IS MORE EXPANSIVE THAN INDICATED BY MODELS. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NEZ004>006-008>010-023>028-035>038-094. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
558 AM CST MON NOV 26 2012 .AVIATION...12Z KGRI TAF...AN APPROACHING DISTURBANCE WILL BRING MVFR CIGS AND VSBYS TO THE TERMINAL DURING THE MORNING HOURS TODAY...WITH CIGS EXPECTED TO EVENTUALLY LIFT...AND VFR CONDS TO RETURN...BY EARLY EVENING. AS OF 11Z...HAVE SEEN SOME IFR CIGS DEVELOP AT ORD...ASSOCIATED WITH AN APPROACHING UPPER LEVEL DISTURBANCE. EXPECT CIGS TO ALSO LOWER AT GRI AS THIS SYSTEM SAGS A BIT FURTHER SOUTH OVER THE NEXT FEW HOURS...WITH THE ATMOSPHERE SATURATING AND SOME -SN DEVELOPING. EXPECT ANY PRECIP THAT DOES DEVELOP...AS WELL AS THE LOWER CIGS...TO DIMINISH BY 18Z...WITH IMPROVING CONDITIONS BY AFTERNOON/EVENING...WITH LITTLE IF ANY SNOWFALL ACCUMULATION AT THE TERMINAL ITSELF. WINDS WILL GENERALLY BE OUT OF THE NORTH AT 10-12KTS THROUGH THE AFTERNOON HOURS...BECOMING LIGHT AND VARIABLE AFTER SUNSET AS AN AREA OF SURFACE HIGH PRESSURE BUILDS IN ACROSS THE REGION. && .PREV DISCUSSION... /ISSUED 416 AM CST MON NOV 26 2012/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT MAIN THEME: WINTER MAKES A BRIEF APPEARANCE TODAY WITH SOME MINOR ACCUMULATION N OF I-80...THEN A RAPID RECOVERY IN TEMPS TOMORROW AND CONTINUED WARMING THRU MID-WEEK. UPPER-LEVELS: LONGWAVE TROF CONTS TO ORGANIZE OVER THE E PACIFIC... DOWNSTREAM OF THE BERING SEA BLOCKING HIGH. A RIDGE WAS BUILDING ALONG THE W COAST. AS MULTIPLE SHORTWAVE TROFS ORBIT AROUND THE DEVELOPING CUT-OFF LOW /WITHIN THE LONGWAVE TROF/ THE RIDGE WILL GRADUALLY HEAD E TO THE FRONT RANGE OF THE ROCKIES BY WED NGT. BOTTOM LINE...NW FLOW THRU TUE NGT THEN BACKING TO W FLOW WED. AT 09Z A VORT MAX/SHORTWAVE TROF WAS OVER MT/WY AND DROPPING SE. IN ADVANCE OF THIS VORT MAX A BATCH -SN WAS OCCURRING WITHIN A PULSE OF QG FORCING/RRQ OF A 120 KT JET ON THE TROPOPAUSE. THE VORT MAX WILL CONT SE INTO NEB THIS MRNG. SURFACE: COLD/STRONG ARCTIC HIGH PRES WAS OVER ND WITH NE LOW-LEVEL FLOW PROVIDING AN UPSLOPE COMPONENT. THIS HIGH WILL EXPAND AND SINK SWD OVER THE CNTRL PLAINS BY THIS EVNG...THEN INTO THE LOWER MS VALLEY TUE AND THE TN VALLEY WED. 00Z RAOBS SHOW LOTS OF DRY AIR TO OVERCOME. SOME OF THE LIFT WILL GO TOWARD SATURATION WHICH COULD DELAY THE START TIME. USED RAP/NAM 925-850 MB RH OF 90% TO GUIDE OUR POPS AS THAT ISOHUME LINED UP FAIRLY WELL WITH OBSERVED -SN. AFTER A FEW FLURRIES AROUND 06Z...STEADY -SN BEGAN AT ORD AT 08Z. EXPECTATION IS THAT BATCH OF -SN WILL DROP S AND AFFECT MOST OF THE FCST AREA...THOUGH NRN KS COULD ONLY SEE FLURRIES...IF THAT. THIS SWD TREND IS SEEN VIA 00Z/06Z NAM LOW-LEVEL RH. LIFT: THE "BEST" LIFT /QG FORCING COUPLED WITH WEAK FGEN AND MODEST MID-LEVEL INSTABILITY/ OCCURS UNTIL 18Z WHEN TROF PASSES AND SUBSIDENCE TAKES OVER. OVERALL MAGNITUDE OF LIFT IS UNIMPRESSIVE AND IS MOSTLY BELOW THE DENDRITIC GROWTH ZONE /DGZ/. THIS WILL RESULT IN MOSTLY SMALLER RIMED FLAKES. SO EXPECT LOWER SNOW-LIQUID RATIOS. SNOWFALL: AS WE SEE IT NOW A HALF INCH OR LESS ALONG AND N OF I-80 WITH AROUND 1 INCH OVER PARTS OF VALLEY/SHERMAN COUNTIES AND GREELEY/HOWARD COUNTIES COULD END UP CLOSE. JUST A DUSTING FROM HWY 6 UP TO I-80. WHERE CAN THIS ACCUM FCST BREAK DOWN? VALLEY/GREELEY COUNTIES. THE 4KM NMM SNOW ALGORITHM OUTPUTS UP TO 3.5 INCHES. BELIEVE THIS IS A LOW PROBABILITY...BUT SOMETHING TO MONITOR AS WE ARE WATCHING THE THE 30 DBZ SNOWBAND DROPPING SLOWLY DUE S ON LXN RADAR /FROM CNTRL CHERRY COUNTY E TO AINSWORTH AND ONEIL/. ANW VSBY HAS AVERAGED 2 SM AND HAS BEEN AS LOW AS 1 1/2 SM. LESSER QUALITY OF DENDRITES/SMALLER FLAKE SIZES WILL PROBABLY KEEP ACCUMS BELOW ADVISORY LEVEL /3 INCHES/. IF THIS BAND HOLDS TOGETHER...WE COULD SEE 1" IN DAWSON/ BUFFALO COUNTIES. THE COBB ALGORITHM OFFERS 1.4 AT ORD FROM THE 08Z RAP AND 2.4 FROM THE 00Z NAM. HOWEVER...GIVEN ITS SNOW:LIQUID RATIOS LOOK INFLATED GIVEN WEAK VERTICAL MOTION. UNCERTAINTIES: HOW FAR S WITH THE SNOW FALL? WE COULD BE A LITTLE TOO FAR S WITH POPS FOR MEASURABLE LIQUID EQUIV. RAP/NAM SOUNDINGS HAVE A REMNANT DRY LAYER BELOW 4K FT UNTIL 16Z AT HSI. ALSO UNSURE HOW QUICKLY TO DECREASE CLOUD COVER BY 21Z. WE SEE THE CLEAR SKIES OVER NRN SD ON SATELLITE. AFTER 18Z...PCPN INTENSITY WILL DROP OFF SIGNIFICANTLY AND BY 21Z SKIES SHOULD START SEE CLEARING. MODEL DWPTS LOOK TOO LOW ONCE SNOW BEGINS. SO INCREASED DWPTS WHERE WE EXPECT SNOW TO BE FALLING TO CLOSE DWPT DEPRESSIONS. TEMPS PROBABLY GO NOWHERE OVER NEB THRU MIDDAY. AS CLOUDS START TO THIN FROM THE N IN THE AFTN...THEN WE SHOULD SEE SOME RISE. OVER NRN KS THINNER CLOUDS IN THE MRNG WILL ALLOW FOR SOME RISE WHICH PROBABLY STALLS MIDDAY IN THICKENING CLOUDS. TNGT: M/CLEAR. HIGH PRES DRIFTS S OF THE FCST AREA. WINDS TURN LIGHT OR CALM IN THE EVNG THEN DEVELOP FROM THE SW. TEMPS ARE BIAS CORRECTED BLEND OF 2M TEMPS AND THE PREVIOUS GID FCST IN AN ATTEMPT TO CAPTURE BIG RADIATORS /ODX AND LXN/. EXPECT TEENS MOST LOCATIONS EXCEPT FROM HDE-HSI-GRI WHICH WILL REMAIN IN THE LOW 20S. WITH FRESH SNOWCOVER AND WINDS EXPECTED TO GO CALM AT ORD...WOULDN`T BE SURPRISED TO SEE TEMPS END UP IN THE SINGLE DIGITS THERE! TUE: SUNNY AND BREEZY AS TEMPS RETURN TO NORMAL /43-55F/. SW WINDS GUST 20-30 MPH. TUE NGT: M/CLEAR WITH LIGHT/CALM WINDS. ANOTHER COLD NGT WITH AREAS IN VICINITY OF LEXINGTON/ORD IN THE TEENS AGAIN. USED BIAS CORRECTED GUIDANCE TO HELP WITH THESE USUAL COLD SPOTS AND THEIR ASSOCIATED TEMP CURVES...ESPECIALLY IN RAPID DROP-OFF IN THE EVNG. WED: SUNNY. A LITTLE WARMER AND LESS WIND. 46-59F WHICH IS ABOUT 5F ABOVE NORMAL. WED NGT: M/CLEAR WITH A LIGHT SW WIND. 21-32F. ORD PROBABLY GOES CALM FOR A TIME A DECOUPLES AGAIN. LONG TERM...THURSDAY THROUGH SUNDAY...AN UNSEASONABLY WARM AND DRY STRETCH OF WEATHER APPEARS TO BE ON TAP FOR THE LOCAL AREA AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE FLATTENS OUT OVER THE PLAINS AND A FAIRLY ZONAL TO SOUTHWESTERLY FLOW ESTABLISHES ITSELF ALOFT...WITH NO NOTABLE DISTURBANCES CAUGHT IN THIS FLOW TO SPEAK OF. THE 12Z RUN OF THE EC DID HINT AT A WEAK DISTURBANCE POTENTIALLY CROSSING THE LOCAL AREA DURING THE FRIDAY NIGHT/SATURDAY MORNING TIME PERIOD...BUT THE 00Z RUN NOW INDICATES A MORE DIFFUSE UPPER LEVEL DISTURBANCE...AND THE GFS STEERS THIS SAME UPPER LEVEL ENERGY WELL TO OUR NORTH. AS A RESULT...MAINTAINED DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES POTENTIALLY CLIMBING INTO THE UPPER 50S AND LOWER 60S FRIDAY THROUGH SUNDAY...WITH LOW TEMPERATURES EXPECTED TO REMAIN ABOVE FREEZING OVER THE SAME TIME PERIOD. NORMAL HIGH TEMPERATURES OVER THIS TIME FRAME GENERALLY RUN IN THE LOWER 40S AND NORMAL LOW TEMPERATURES RUN IN THE LOWER 20S. LOOKING BEYOND THE CURRENT EXTENT OF THE FORECAST...NO HINTS AT AN END TO THIS WARM A DRY PERIOD IN MODEL DATA THROUGH AT LEAST THE MIDDLE OF FOLLOWING WEEK AT THIS TIME. CLIMATE...WITH THE END OF THE YEAR NOW IN SIGHT...IF ANOTHER 2.16 INCHES OF LIQUID PRECIPITATION DOES NOT ACCUMULATE AT THE CENTRAL NEBRASKA REGIONAL AIRPORT IN GRAND ISLAND...2012 STANDS TO BE THE DRIEST FULL YEAR ON RECORD SINCE 1896...WHEN THE FIRST FULL YEAR OF RECORD KEEPING BEGAN IN THE GRAND ISLAND AREA. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HALBLAUB LONG TERM/AVIATION...ROSSI
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
529 AM CST MON NOV 26 2012 .UPDATE... .AVIATION... IFR IS EXPECTED THROUGH ROUGHLY 16-18Z THIS AM AS THE SNOW AND LOW CIGS GRADUALLY WEAKEN. NOTE THE SNOW ARRIVAL AT KLBF IS BASED ON THE CURRENT RADAR TRENDS WHICH COULD CHANGE AT ANY TIME AS AN UPPER LEVEL KICKER ACROSS NERN WYOMING THIS MORNING APPROACHES WHICH WOULD CAUSE THE SNOW BAND TO FALL APART. ALSO THE SNOW ENDING TIME AT KVTN IS ESSENTIALLY A MODEL GUESS AS THE RADAR IS OVERSHOOTING THE SNOW AT THAT LOCATION SUGGESTING THE SNOW WILL END AT ANY TIME. VFR COULD BE WIDESPREAD BY 18Z AND CONTINUE OVERNIGHT AS HIGH PRESSURE BUILDS INTO THE REGION. && .PREV DISCUSSION... /ISSUED 437 AM CST MON NOV 26 2012/ UPDATE... REPORTS FROM FROM THE NEBRASKA DEPARTMENT OF ROADS AND RADAR SUGGEST SNOW WILL CONTINUE TO ACCUMULATE ON ROADWAYS THROUGH AT LEAST SUNRISE. ADDITIONAL COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY. TEMPERATURES CONTINUE TO FALL INTO THE LOWER 20S ACROSS NRN NEBRASKA SUGGESTING A HIGH PROBABILITY OF ICING ON ROADWAYS WITH ROAD SFCS LIKELY CROSSING THE FREEZING MARK. THE FRONTOGENETICALLY FORCED SNOW BAND ACROSS THE SANDHILLS IS SHOWING SIGNS OF TIGHTENING UP AS VERY COLD 700MB AIR DRIVES SOUTH AND COLLIDES WITH WARM MID LEVEL TO THE SOUTH NEAR KLBF. PREV DISCUSSION... /ISSUED 351 AM CST MON NOV 26 2012/ DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. AVIATION...EXPECTING MAINLY MVFR CONDITIONS WITH 5SM -SN AT KVTN THROUGH 12Z.VFR CONDITIONS SHOULD PREVAIL BY 15Z. SNOWFALL AREA TO DEVELOP SOUTH OVERNIGHT INTO MONDAY MORNING AS A SHORTWAVE TROUGH MOVES ACROSS EASTERN WYOMING INTO THE NEBRASKA PANHANDLE. CURRENT VFR CONDITIONS AT KLBF SHOULD TRANSITION TO MVFR CEILINGS BETWEEN 09Z-12Z WITH P6SM -SN WITH TEMPO OF 2SM -SN AFTER 12Z. MVFR CONDITIONS COULD PERSIST INTO THE AFTERNOON IF SYSTEM SLOWS OR IS MORE EXPANSIVE THAN INDICATED BY MODELS. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NEZ004>006-008>010-023>028-094. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
437 AM CST MON NOV 26 2012 .UPDATE... REPORTS FROM FROM THE NEBRASKA DEPARTMENT OF ROADS AND RADAR SUGGEST SNOW WILL CONTINUE TO ACCUMULATE ON ROADWAYS THROUGH AT LEAST SUNRISE. ADDITIONAL COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY. TEMPERATURES CONTINUE TO FALL INTO THE LOWER 20S ACROSS NRN NEBRASKA SUGGESTING A HIGH PROBABILITY OF ICING ON ROADWAYS WITH ROAD SFCS LIKELY CROSSING THE FREEZING MARK. THE FRONTOGENETICALLY FORCED SNOW BAND ACROSS THE SANDHILLS IS SHOWING SIGNS OF TIGHTENING UP AS VERY COLD 700MB AIR DRIVES SOUTH AND COLLIDES WITH WARM MID LEVEL TO THE SOUTH NEAR KLBF. && .PREV DISCUSSION... /ISSUED 351 AM CST MON NOV 26 2012/ DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. AVIATION...EXPECTING MAINLY MVFR CONDITIONS WITH 5SM -SN AT KVTN THROUGH 12Z.VFR CONDITIONS SHOULD PREVAIL BY 15Z. SNOWFALL AREA TO DEVELOP SOUTH OVERNIGHT INTO MONDAY MORNING AS A SHORTWAVE TROUGH MOVES ACROSS EASTERN WYOMING INTO THE NEBRASKA PANHANDLE. CURRENT VFR CONDITIONS AT KLBF SHOULD TRANSITION TO MVFR CEILINGS BETWEEN 09Z-12Z WITH P6SM -SN WITH TEMPO OF 2SM -SN AFTER 12Z. MVFR CONDITIONS COULD PERSIST INTO THE AFTERNOON IF SYSTEM SLOWS OR IS MORE EXPANSIVE THAN INDICATED BY MODELS. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NEZ004>006-008>010-023>028-094. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
416 AM CST MON NOV 26 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT MAIN THEME: WINTER MAKES A BRIEF APPEARANCE TODAY WITH SOME MINOR ACCUMULATION N OF I-80...THEN A RAPID RECOVERY IN TEMPS TOMORROW AND CONTINUED WARMING THRU MID-WEEK. UPPER-LEVELS: LONGWAVE TROF CONTS TO ORGANIZE OVER THE E PACIFIC... DOWNSTREAM OF THE BERING SEA BLOCKING HIGH. A RIDGE WAS BUILDING ALONG THE W COAST. AS MULTIPLE SHORTWAVE TROFS ORBIT AROUND THE DEVELOPING CUT-OFF LOW /WITHIN THE LONGWAVE TROF/ THE RIDGE WILL GRADUALLY HEAD E TO THE FRONT RANGE OF THE ROCKIES BY WED NGT. BOTTOM LINE...NW FLOW THRU TUE NGT THEN BACKING TO W FLOW WED. AT 09Z A VORT MAX/SHORTWAVE TROF WAS OVER MT/WY AND DROPPING SE. IN ADVANCE OF THIS VORT MAX A BATCH -SN WAS OCCURRING WITHIN A PULSE OF QG FORCING/RRQ OF A 120 KT JET ON THE TROPOPAUSE. THE VORT MAX WILL CONT SE INTO NEB THIS MRNG. SURFACE: COLD/STRONG ARCTIC HIGH PRES WAS OVER ND WITH NE LOW-LEVEL FLOW PROVIDING AN UPSLOPE COMPONENT. THIS HIGH WILL EXPAND AND SINK SWD OVER THE CNTRL PLAINS BY THIS EVNG...THEN INTO THE LOWER MS VALLEY TUE AND THE TN VALLEY WED. 00Z RAOBS SHOW LOTS OF DRY AIR TO OVERCOME. SOME OF THE LIFT WILL GO TOWARD SATURATION WHICH COULD DELAY THE START TIME. USED RAP/NAM 925-850 MB RH OF 90% TO GUIDE OUR POPS AS THAT ISOHUME LINED UP FAIRLY WELL WITH OBSERVED -SN. AFTER A FEW FLURRIES AROUND 06Z...STEADY -SN BEGAN AT ORD AT 08Z. EXPECTATION IS THAT BATCH OF -SN WILL DROP S AND AFFECT MOST OF THE FCST AREA...THOUGH NRN KS COULD ONLY SEE FLURRIES...IF THAT. THIS SWD TREND IS SEEN VIA 00Z/06Z NAM LOW-LEVEL RH. LIFT: THE "BEST" LIFT /QG FORCING COUPLED WITH WEAK FGEN AND MODEST MID-LEVEL INSTABILITY/ OCCURS UNTIL 18Z WHEN TROF PASSES AND SUBSIDENCE TAKES OVER. OVERALL MAGNITUDE OF LIFT IS UNIMPRESSIVE AND IS MOSTLY BELOW THE DENDRITIC GROWTH ZONE /DGZ/. THIS WILL RESULT IN MOSTLY SMALLER RIMED FLAKES. SO EXPECT LOWER SNOW-LIQUID RATIOS. SNOWFALL: AS WE SEE IT NOW A HALF INCH OR LESS ALONG AND N OF I-80 WITH AROUND 1 INCH OVER PARTS OF VALLEY/SHERMAN COUNTIES AND GREELEY/HOWARD COUNTIES COULD END UP CLOSE. JUST A DUSTING FROM HWY 6 UP TO I-80. WHERE CAN THIS ACCUM FCST BREAK DOWN? VALLEY/GREELEY COUNTIES. THE 4KM NMM SNOW ALGORITHM OUTPUTS UP TO 3.5 INCHES. BELIEVE THIS IS A LOW PROBABILITY...BUT SOMETHING TO MONITOR AS WE ARE WATCHING THE THE 30 DBZ SNOWBAND DROPPING SLOWLY DUE S ON LXN RADAR /FROM CNTRL CHERRY COUNTY E TO AINSWORTH AND ONEIL/. ANW VSBY HAS AVERAGED 2 SM AND HAS BEEN AS LOW AS 1 1/2 SM. LESSER QUALITY OF DENDRITES/SMALLER FLAKE SIZES WILL PROBABLY KEEP ACCUMS BELOW ADVISORY LEVEL /3 INCHES/. IF THIS BAND HOLDS TOGETHER...WE COULD SEE 1" IN DAWSON/ BUFFALO COUNTIES. THE COBB ALGORITHM OFFERS 1.4 AT ORD FROM THE 08Z RAP AND 2.4 FROM THE 00Z NAM. HOWEVER...GIVEN ITS SNOW:LIQUID RATIOS LOOK INFLATED GIVEN WEAK VERTICAL MOTION. UNCERTAINTIES: HOW FAR S WITH THE SNOW FALL? WE COULD BE A LITTLE TOO FAR S WITH POPS FOR MEASURABLE LIQUID EQUIV. RAP/NAM SOUNDINGS HAVE A REMNANT DRY LAYER BELOW 4K FT UNTIL 16Z AT HSI. ALSO UNSURE HOW QUICKLY TO DECREASE CLOUD COVER BY 21Z. WE SEE THE CLEAR SKIES OVER NRN SD ON SATELLITE. AFTER 18Z...PCPN INTENSITY WILL DROP OFF SIGNIFICANTLY AND BY 21Z SKIES SHOULD START SEE CLEARING. MODEL DWPTS LOOK TOO LOW ONCE SNOW BEGINS. SO INCREASED DWPTS WHERE WE EXPECT SNOW TO BE FALLING TO CLOSE DWPT DEPRESSIONS. TEMPS PROBABLY GO NOWHERE OVER NEB THRU MIDDAY. AS CLOUDS START TO THIN FROM THE N IN THE AFTN...THEN WE SHOULD SEE SOME RISE. OVER NRN KS THINNER CLOUDS IN THE MRNG WILL ALLOW FOR SOME RISE WHICH PROBABLY STALLS MIDDAY IN THICKENING CLOUDS. TNGT: M/CLEAR. HIGH PRES DRIFTS S OF THE FCST AREA. WINDS TURN LIGHT OR CALM IN THE EVNG THEN DEVELOP FROM THE SW. TEMPS ARE BIAS CORRECTED BLEND OF 2M TEMPS AND THE PREVIOUS GID FCST IN AN ATTEMPT TO CAPTURE BIG RADIATORS /ODX AND LXN/. EXPECT TEENS MOST LOCATIONS EXCEPT FROM HDE-HSI-GRI WHICH WILL REMAIN IN THE LOW 20S. WITH FRESH SNOWCOVER AND WINDS EXPECTED TO GO CALM AT ORD...WOULDN`T BE SURPRISED TO SEE TEMPS END UP IN THE SINGLE DIGITS THERE! TUE: SUNNY AND BREEZY AS TEMPS RETURN TO NORMAL /43-55F/. SW WINDS GUST 20-30 MPH. TUE NGT: M/CLEAR WITH LIGHT/CALM WINDS. ANOTHER COLD NGT WITH AREAS IN VICINITY OF LEXINGTON/ORD IN THE TEENS AGAIN. USED BIAS CORRECTED GUIDANCE TO HELP WITH THESE USUAL COLD SPOTS AND THEIR ASSOCIATED TEMP CURVES...ESPECIALLY IN RAPID DROP-OFF IN THE EVNG. WED: SUNNY. A LITTLE WARMER AND LESS WIND. 46-59F WHICH IS ABOUT 5F ABOVE NORMAL. WED NGT: M/CLEAR WITH A LIGHT SW WIND. 21-32F. ORD PROBABLY GOES CALM FOR A TIME A DECOUPLES AGAIN. .LONG TERM...THURSDAY THROUGH SUNDAY...AN UNSEASONABLY WARM AND DRY STRETCH OF WEATHER APPEARS TO BE ON TAP FOR THE LOCAL AREA AS AN UPPER LEVEL RIDGE OF HIGH PRESSURE FLATTENS OUT OVER THE PLAINS AND A FAIRLY ZONAL TO SOUTHWESTERLY FLOW ESTABLISHES ITSELF ALOFT...WITH NO NOTABLE DISTURBANCES CAUGHT IN THIS FLOW TO SPEAK OF. THE 12Z RUN OF THE EC DID HINT AT A WEAK DISTURBANCE POTENTIALLY CROSSING THE LOCAL AREA DURING THE FRIDAY NIGHT/SATURDAY MORNING TIME PERIOD...BUT THE 00Z RUN NOW INDICATES A MORE DIFFUSE UPPER LEVEL DISTURBANCE...AND THE GFS STEERS THIS SAME UPPER LEVEL ENERGY WELL TO OUR NORTH. AS A RESULT...MAINTAINED DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES POTENTIALLY CLIMBING INTO THE UPPER 50S AND LOWER 60S FRIDAY THROUGH SUNDAY...WITH LOW TEMPERATURES EXPECTED TO REMAIN ABOVE FREEZING OVER THE SAME TIME PERIOD. NORMAL HIGH TEMPERATURES OVER THIS TIME FRAME GENERALLY RUN IN THE LOWER 40S AND NORMAL LOW TEMPERATURES RUN IN THE LOWER 20S. LOOKING BEYOND THE CURRENT EXTENT OF THE FORECAST...NO HINTS AT AN END TO THIS WARM A DRY PERIOD IN MODEL DATA THROUGH AT LEAST THE MIDDLE OF FOLLOWING WEEK AT THIS TIME. .CLIMATE...WITH THE END OF THE YEAR NOW IN SIGHT...IF ANOTHER 2.16 INCHES OF LIQUID PRECIPITATION DOES NOT ACCUMULATE AT THE CENTRAL NEBRASKA REGIONAL AIRPORT IN GRAND ISLAND...2012 STANDS TO BE THE DRIEST FULL YEAR ON RECORD SINCE 1896...WHEN THE FIRST FULL YEAR OF RECORD KEEPING BEGAN IN THE GRAND ISLAND AREA. && .PREV DISCUSSION... /ISSUED 1052 PM CST SUN NOV 25 2012/ AVIATION...06Z TAF. CLOUDS WILL CONTINUE TO THICKEN AND LOWER DURING THE OVERNIGHT HOURS AS AN UPPER LEVEL DISTURBANCE AND FRONTAL BOUNDARY CROSS THE CENTRAL PLAINS. IN INCREASING DYNAMICS TOWARD MORNING...SOME LIGHT SNOW IS POSSIBLE FOR A FEW HOURS AT KGRI BUT WITH LITTLE IF ANY ACCUMULATION EXPECTED. CLOUDS ARE MAINLY FORECAST TO DROP TO THE MVFR CATEGORY BUT CANNOT COMPLETELY RULE OUT A BRIEF PERIOD OF IFR CIGS. THE SYSTEM WILL PASS AROUND MID DAY WITH CLOUDS SCATTERING IN THE AFTN. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...HALBLAUB LONG TERM...ROSSI CLIMATE...ROSSI AVIATION...FAY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
351 AM CST MON NOV 26 2012 .DISCUSSION...WATCHING RADAR TRENDS VERY CLOSELY EARLY THIS MORNING. RAPID UPDATE MODEL /RAP/ SUGGESTS A TIGHTENING BAND OF FRONTOGENESIS THIS MORNING FROM NEAR ALLIANCE SOUTHEAST THROUGH NORTH PLATTE. THIS APPEARS TO BE OCCURRING...BUT MORE ACROSS NORTH CENTRAL NEBRASKA...WHERE A TIGHTENING BAND OF SNOW IS EVIDENT ON RADAR...WHICH IS SLOWLY DROPPING SOUTH. THIS IS LIKELY IN RESPONSE TO A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM UPSTREAM OVER WYOMING. THE RAP MODEL SUGGESTS A COUPLE OF INCHES MAY ACCUMULATE THIS MORNING...AND A CROSS SECTION OF THE RAP SUGGESTS STRONG LIFT AND SOME INSTABILITY WITHIN THE BAND OF FRONTOGENESIS...SO WILL MONITOR THIS VERY CAREFULLY FOR ANY DEVELOPMENT OF BANDED SNOW WHICH COULD OCCUR FOR A TIME. OTHERWISE A WINTER WEATHER ADVISORY WAS ISSUED LAST NIGHT FOR NORTH CENTRAL NEBRASKA...WHERE LIGHT TO MODERATE SNOW FELL ALL DAY SUNDAY. FOUR INCHES OF SNOW HAD ACCUMULATED AT VALENTINE AS OF MIDNIGHT...AND ANOTHER INCH WAS STILL EXPECTED TO FALL. TRAVEL HAD SLOWED CONSIDERABLE ON THE MAIN HIGHWAYS...AND WANTED TO GET THE WORD OUT THAT TRAVEL MAY BE RATHER DIFFICULT DURING THE MORNING HOURS. SNOWFALL AMOUNTS RANGED FROM 2 TO 5 INCHES ACROSS NORTH CENTRAL AND NORTHWEST NEBRASKA. FORTUNATELY WIND WAS LIGHT...SO BLOWING AND DRIFTING WAS NOT A PROBLEM. ANY SNOW WHICH DEVELOPS THIS MORNING ASSOCIATED WITH THE WEAK DISTURBANCE MOVING ACROSS SHOULD END EARLY THIS AFTERNOON. MODELS SUGGEST THAT CLOUD COVER MAY LINGER WELL INTO THE AFTERNOON...AND HAVE SLOWED DOWN THE CLEARING OF SKIES SOME. A WARM UP IS STILL EXPECTED TUESDAY AND BEYOND AS BRIEF RIDGING ALOFT TUESDAY AND WEDNESDAY TRANSITIONS TO NEAR ZONAL FLOW THURSDAY INTO THE UPCOMING WEEKEND. AFTER THE SNOW TODAY...THE REST OF THE WEEK LOOKS DRY. ANY ARCTIC AIR WILL REMAIN BOTTLED UP TO OUR NORTH. HIGHS WILL GENERALLY RANGE FROM THE 40S NORTHERN NEBRASKA...TO THE 50S SOUTHERN NEBRASKA TUESDAY THROUGH THURSDAY. 50S THEN EXPECTED ALL AREAS FRIDAY INTO THE WEEKEND...WITH A FEW 60 DEGREE READINGS POSSIBLE ACROSS WESTERN AND SOUTHWEST NEBRASKA. && .AVIATION...EXPECTING MAINLY MVFR CONDITIONS WITH 5SM -SN AT KVTN THROUGH 12Z.VFR CONDITIONS SHOULD PREVAIL BY 15Z. SNOWFALL AREA TO DEVELOP SOUTH OVERNIGHT INTO MONDAY MORNING AS A SHORTWAVE TROUGH MOVES ACROSS EASTERN WYOMING INTO THE NEBRASKA PANHANDLE. CURRENT VFR CONDITIONS AT KLBF SHOULD TRANSITION TO MVFR CEILINGS BETWEEN 09Z-12Z WITH P6SM -SN WITH TEMPO OF 2SM -SN AFTER 12Z. MVFR CONDITIONS COULD PERSIST INTO THE AFTERNOON IF SYSTEM SLOWS OR IS MORE EXPANSIVE THAN INDICATED BY MODELS. && .LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR NEZ004>006-008-009-094. && $$ DISCUSSION...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
300 PM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12 NOON UPDATE... THE LES BAND IS BEHAVING WELL EARLY THIS AFTN...WITH THE ANTICIPATED NWD SHIFT JUST ABT TO GET UNDERWAY...AS JUDGED FROM UPSTREAM RADAR/SAT/VWP TRENDS. WE EXPECT A FRACTURED LOOKING BAND TO CROSS THE THRUWAY CORRIDOR THROUGH ABT 18Z...THEN REACH THE SRN TUG HILL RGN AGN BY MID TO LATE AFTN. BASED ON MARGINAL SFC TEMPS AND WANING OVERALL INTENSITY...ANY ADDTNL ACCUMS LOOK MINOR FOR THE REST OF THE DAYLIGHT HRS (MAINLY UNDER AN INCH). JUST MINOR TWEAKS MADE TO SKY/TEMP/DEW PT GRIDS EARLY THIS AFTN...OTHWS THINGS IN GOOD SHAPE ATTM. PREV DISC... 9 AM UPDATE... MAIN FOCUS IS ON LES BAND LATE THIS MRNG. IN GENERAL...THE BAND HAS EXHIBITED A SLOW SWD DRIFT THE PAST FEW HRS...AND ITS APPEARANCE HAS BECOME A BIT MORE RAGGED SINCE ABT 13Z. WE EXPECT BOTH OF THESE TRENDS TO HOLD THROUGH MIDDAY/EARLY AFTN...AS THE LOW-LVL FLOW SLOWLY VEERS...AND INCREASING TERRESTRIAL INSTAB DETRACTS FROM BAND ORGANIZATION. WHERE THE BAND IS MOST PERSISTENT THROUGH 16-17Z...WE`RE INDICATING LOCALIZED 1-1.5" AMTS. BASED ON RECENT REPORTS AND WEB CAM SHOTS FROM IN AND ARND KSYR...BRIEF SHSN/+SHSN ARE ONLY BEING EXPERIENCED RIGHT UNDERNEATH THE MIDDLE OF THE BAND...WITH INTENSITY QUICKLY TAPERING OFF OUTSIDE OF THE BAND CENTERLINE. THIS AFTN...THERE IS GOOD AGREEMENT AMONGST OUR NEAR-TERM HI RES MODELS (4-12 KM NAM...HRRR...AND OUR LOCAL WRF) THAT THE BAND (ALBEIT IN A "BROKEN UP" STATE) WILL BEGIN TO DRIFT BACK NWD...LIKELY REACHING NRN ONEIDA BY 18-21Z. AS A RESULT...WE HAVE A SMATTERING OF ADDTNL ACCUMS THIS AFTN IN FAR NRN ONONDAGA...NRN MADISON...AND ONEIDA (MOSTLY LESS THAN AN INCH). OUTSIDE OF LES IMPACTED AREAS...JUST A FEW FLRYS...AT WORST...ARE ANTICIPATED THROUGH THE DAY. GENERALLY CLEAR SKIES ACRS NE PA ATTM...SHOULD BECOME PARTLY SUNNY BY EARLY AFTN...WITH SOME MOISTURE STILL TRAPPED UNDERNEATH A SUBSIDENCE INVERSION (SHOWN ON KBUF...KALY...AND KPIT 12Z SNDGS). NEAR-TERM TEMP/DEW PT GRIDS WERE TWEAKED JUST A LTL...WITH OUR AFTN MAX TEMP FCST LOOKING SOLD ATTM. EARLIER DISC... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFORE THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... 230 PM UPDATE... WHILE THE SPECIFICS ARE STILL UP IN THE AIR WITH REGARDS TO PRECIP TIMING AND EVEN SOME PTYPE ISSUES IN THE LONG TERM...THE MAIN THEME IS A ZONAL FLOW AND MUCH MILDER AIR THIS WEEKEND INTO EARLY NEXT WEEK. WE EXPECT MAINLY DRY WEATHER THROUGH THE END OF THE WEEK AND IT WILL REMAIN WELL BELOW NORMAL WITH HIGHS NEAR FREEZING AGAIN FRIDAY. MAJOR TIMING DIFFERENCES BEGIN TO SHOW UP FRIDAY NIGHT INTO SATURDAY. THE GFS IS IN ONE CAMP WITH A FASTER WARM-UP...AND UNSETTLED WEATHER AS EARLY AS FRIDAY NIGHT/SATURDAY. THE EURO AND CANADIAN ARE IN ANOTHER CAMP WITH A MUCH SLOWER WARM-UP...AND DRY WEATHER UNTIL THE 2ND HALF OF THE WEEKEND. FAVOR THE 2ND SOLUTION AS THE MODELS HAVE HAD TROUBLE RECENTLY TRYING TO DISLODGE THE COLD AIR TOO FAST AND THIS IS ALSO MORE IN LINE WITH OUR PREVIOUS FORECAST. WITH THAT SAID WILL KEEP THE FIRST HALF OF THE WEEKEND DRY WITH TEMPS CLOSER TO NORMAL VALUES FOR EARLY DECEMBER OR INTO THE LOWER 40S. THE BULK OF THE PRECIP ARRIVES ON SUNDAY IN THE FORM OF PLAIN RAIN AS 850 TEMPS SURGE ABOVE 0C. WE WILL HAVE TO WATCH EARLY SUNDAY MORNING CAREFULLY BECAUSE SURFACE TEMPS MAY BE COLD ENOUGH FOR SOME PTYPE ISSUES IF THE PRECIP ARRIVES EARLY ENOUGH ESPECIALLY EAST OF 81. AS A TROF DIGS INTO THE WESTERN US...HEIGHTS WILL CONTINUE TO BUILD EARLY NEXT WEEK. WITH 850S APPROACHING THE UPPER SINGLE DIGITS...TEMPS LOOK TO REMAIN WELL ABOVE NORMAL THROUGH EARLY IN THE WEEK. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... 1 PM UPDATE...A BAND OF LAKE EFFECT SNOW IMPACTING KSYR NOW...WILL GRADUALLY LIFT NORTH BY 20Z AS WINDS BEGIN TO BACK TOWARD THE WEST. MVFR VSBYS POSSIBLE HERE THROUGH 20Z UNTIL THE BAND LIFTS NORTH OF THE TERMINAL. AT KRME...BRIEF IFR VSYBS POSSIBLE THROUGH 20Z AS THE BAND MOVES THROUGH. ELSEWHERE GENERALLY VFR CONDITIONS ARE EXPECTED THIS AFTERNOON AS CLOUDS INCREASE THANKS TO LAKE CLOUDS MOVING IN OFF LAKE ERIE. HIGHEST IMPACT WILL BE AT THE NY TERMINALS WHERE CIGS WILL BE IN THE 4KFT TO 5KFT RANGE...EXCEPT AT KITH/KBGM WHERE ELEVATION MAY BE ENOUGH TO GIVE US BORDERLINE MVFR CIGS THROUGH EARLY EVENING. LATE TONIGHT AFTER A BRIEF BREAK WITH VFR...MVFR CIGS RETURN TO ALL TERMINALS BETWEEN 06Z AND 12Z. ACROSS THE SOUTHERN TERMINALS FROM KELM THROUGH KBGM/KAVP MVFR TO IFR VSBYS LIKELY IN LIGHT SNOW. BEST CHANCE AT IFR WILL BE AT KAVP..WHERE VSBYS UNDER A MILE ARE POSSIBLE NEAR DAYBREAK. CONDITIONS IMPROVE TO MVFR BY MID MORNING AS DRIER AIR WORKS IN FROM THE WEST. OUTLOOK... WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI/SAT...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP/MLJ SHORT TERM...DJP LONG TERM...HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
112 PM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12 NOON UPDATE... THE LES BAND IS BEHAVING WELL EARLY THIS AFTN...WITH THE ANTICIPATED NWD SHIFT JUST ABT TO GET UNDERWAY...AS JUDGED FROM UPSTREAM RADAR/SAT/VWP TRENDS. WE EXPECT A FRACTURED LOOKING BAND TO CROSS THE THRUWAY CORRIDOR THROUGH ABT 18Z...THEN REACH THE SRN TUG HILL RGN AGN BY MID TO LATE AFTN. BASED ON MARGINAL SFC TEMPS AND WANING OVERALL INTENSITY...ANY ADDTNL ACCUMS LOOK MINOR FOR THE REST OF THE DAYLIGHT HRS (MAINLY UNDER AN INCH). JUST MINOR TWEAKS MADE TO SKY/TEMP/DEW PT GRIDS EARLY THIS AFTN...OTHWS THINGS IN GOOD SHAPE ATTM. PREV DISC... 9 AM UPDATE... MAIN FOCUS IS ON LES BAND LATE THIS MRNG. IN GENERAL...THE BAND HAS EXHIBITED A SLOW SWD DRIFT THE PAST FEW HRS...AND ITS APPEARANCE HAS BECOME A BIT MORE RAGGED SINCE ABT 13Z. WE EXPECT BOTH OF THESE TRENDS TO HOLD THROUGH MIDDAY/EARLY AFTN...AS THE LOW-LVL FLOW SLOWLY VEERS...AND INCREASING TERRESTRIAL INSTAB DETRACTS FROM BAND ORGANIZATION. WHERE THE BAND IS MOST PERSISTENT THROUGH 16-17Z...WE`RE INDICATING LOCALIZED 1-1.5" AMTS. BASED ON RECENT REPORTS AND WEB CAM SHOTS FROM IN AND ARND KSYR...BRIEF SHSN/+SHSN ARE ONLY BEING EXPERIENCED RIGHT UNDERNEATH THE MIDDLE OF THE BAND...WITH INTENSITY QUICKLY TAPERING OFF OUTSIDE OF THE BAND CENTERLINE. THIS AFTN...THERE IS GOOD AGREEMENT AMONGST OUR NEAR-TERM HI RES MODELS (4-12 KM NAM...HRRR...AND OUR LOCAL WRF) THAT THE BAND (ALBEIT IN A "BROKEN UP" STATE) WILL BEGIN TO DRIFT BACK NWD...LIKELY REACHING NRN ONEIDA BY 18-21Z. AS A RESULT...WE HAVE A SMATTERING OF ADDTNL ACCUMS THIS AFTN IN FAR NRN ONONDAGA...NRN MADISON...AND ONEIDA (MOSTLY LESS THAN AN INCH). OUTSIDE OF LES IMPACTED AREAS...JUST A FEW FLRYS...AT WORST...ARE ANTICIPATED THROUGH THE DAY. GENERALLY CLEAR SKIES ACRS NE PA ATTM...SHOULD BECOME PARTLY SUNNY BY EARLY AFTN...WITH SOME MOISTURE STILL TRAPPED UNDERNEATH A SUBSIDENCE INVERSION (SHOWN ON KBUF...KALY...AND KPIT 12Z SNDGS). NEAR-TERM TEMP/DEW PT GRIDS WERE TWEAKED JUST A LTL...WITH OUR AFTN MAX TEMP FCST LOOKING SOLD ATTM. EARLIER DISC... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFORE THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MADE SOME SLIGHT ADJUSTMENTS BASED ON LATEST INFORMATION...THOUGH MODEL DIFFERENCES STILL EXIST FRIDAY ONWARD. DEGREE OF AMPLIFICATION OF FLOW IN QUESTION...BUT EITHER WAY HEIGHTS/THICKNESSES WILL RISE THIS THE WEEKEND WHICH SHOULD LEAD TO AREA WIDE 40S BY SUNDAY...WITH NIGHTS STAYING ABOVE FREEZING FOR MOST IF NOT ALL OF AREA SATURDAY NIGHT ONWARD. IF PRECIPITATION RUNS WELL OUT AHEAD DURING TRANSITION PERIOD SATURDAY SUCH AS DEPICTED IN GFS...SOME QUESTION AS TO WHICH TYPE IT WOULD BE /LIGHT WINTRY MIX NOT OUT OF QUESTION/...BUT AT THIS POINT AS PER ECMWF WE DO NOT HAVE CHANCE POPS IN REGION UNTIL SAT NIGHT-SUNDAY DURING WHICH P-TYPE WOULD BE ALMOST EXCLUSIVELY RAIN. PREVIOUS DISCUSSION... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... 1 PM UPDATE...A BAND OF LAKE EFFECT SNOW IMPACTING KSYR NOW...WILL GRADUALLY LIFT NORTH BY 20Z AS WINDS BEGIN TO BACK TOWARD THE WEST. MVFR VSBYS POSSIBLE HERE THROUGH 20Z UNTIL THE BAND LIFTS NORTH OF THE TERMINAL. AT KRME...BRIEF IFR VSYBS POSSIBLE THROUGH 20Z AS THE BAND MOVES THROUGH. ELSEWHERE GENERALLY VFR CONDITIONS ARE EXPECTED THIS AFTERNOON AS CLOUDS INCREASE THANKS TO LAKE CLOUDS MOVING IN OFF LAKE ERIE. HIGHEST IMPACT WILL BE AT THE NY TERMINALS WHERE CIGS WILL BE IN THE 4KFT TO 5KFT RANGE...EXCEPT AT KITH/KBGM WHERE ELEVATION MAY BE ENOUGH TO GIVE US BORDERLINE MVFR CIGS THROUGH EARLY EVENING. LATE TONIGHT AFTER A BRIEF BREAK WITH VFR...MVFR CIGS RETURN TO ALL TERMINALS BETWEEN 06Z AND 12Z. ACROSS THE SOUTHERN TERMINALS FROM KELM THROUGH KBGM/KAVP MVFR TO IFR VSBYS LIKELY IN LIGHT SNOW. BEST CHANCE AT IFR WILL BE AT KAVP..WHERE VSBYS UNDER A MILE ARE POSSIBLE NEAR DAYBREAK. CONDITIONS IMPROVE TO MVFR BY MID MORNING AS DRIER AIR WORKS IN FROM THE WEST. OUTLOOK... WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI/SAT...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP/MLJ SHORT TERM...DJP LONG TERM...MDP/MSE AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1207 PM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 12 NOON UPDATE... THE LES BAND IS BEHAVING WELL EARLY THIS AFTN...WITH THE ANTICIPATED NWD SHIFT JUST ABT TO GET UNDERWAY...AS JUDGED FROM UPSTREAM RADAR/SAT/VWP TRENDS. WE EXPECT A FRACTURED LOOKING BAND TO CROSS THE THRUWAY CORRIDOR THROUGH ABT 18Z...THEN REACH THE SRN TUG HILL RGN AGN BY MID TO LATE AFTN. BASED ON MARGINAL SFC TEMPS AND WANING OVERALL INTENSITY...ANY ADDTNL ACCUMS LOOK MINOR FOR THE REST OF THE DAYLIGHT HRS (MAINLY UNDER AN INCH). JUST MINOR TWEAKS MADE TO SKY/TEMP/DEW PT GRIDS EARLY THIS AFTN...OTHWS THINGS IN GOOD SHAPE ATTM. PREV DISC... 9 AM UPDATE... MAIN FOCUS IS ON LES BAND LATE THIS MRNG. IN GENERAL...THE BAND HAS EXHIBITED A SLOW SWD DRIFT THE PAST FEW HRS...AND ITS APPEARANCE HAS BECOME A BIT MORE RAGGED SINCE ABT 13Z. WE EXPECT BOTH OF THESE TRENDS TO HOLD THROUGH MIDDAY/EARLY AFTN...AS THE LOW-LVL FLOW SLOWLY VEERS...AND INCREASING TERRESTRIAL INSTAB DETRACTS FROM BAND ORGANIZATION. WHERE THE BAND IS MOST PERSISTENT THROUGH 16-17Z...WE`RE INDICATING LOCALIZED 1-1.5" AMTS. BASED ON RECENT REPORTS AND WEB CAM SHOTS FROM IN AND ARND KSYR...BRIEF SHSN/+SHSN ARE ONLY BEING EXPERIENCED RIGHT UNDERNEATH THE MIDDLE OF THE BAND...WITH INTENSITY QUICKLY TAPERING OFF OUTSIDE OF THE BAND CENTERLINE. THIS AFTN...THERE IS GOOD AGREEMENT AMONGST OUR NEAR-TERM HI RES MODELS (4-12 KM NAM...HRRR...AND OUR LOCAL WRF) THAT THE BAND (ALBEIT IN A "BROKEN UP" STATE) WILL BEGIN TO DRIFT BACK NWD...LIKELY REACHING NRN ONEIDA BY 18-21Z. AS A RESULT...WE HAVE A SMATTERING OF ADDTNL ACCUMS THIS AFTN IN FAR NRN ONONDAGA...NRN MADISON...AND ONEIDA (MOSTLY LESS THAN AN INCH). OUTSIDE OF LES IMPACTED AREAS...JUST A FEW FLRYS...AT WORST...ARE ANTICIPATED THROUGH THE DAY. GENERALLY CLEAR SKIES ACRS NE PA ATTM...SHOULD BECOME PARTLY SUNNY BY EARLY AFTN...WITH SOME MOISTURE STILL TRAPPED UNDERNEATH A SUBSIDENCE INVERSION (SHOWN ON KBUF...KALY...AND KPIT 12Z SNDGS). NEAR-TERM TEMP/DEW PT GRIDS WERE TWEAKED JUST A LTL...WITH OUR AFTN MAX TEMP FCST LOOKING SOLD ATTM. EARLIER DISC... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFORE THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MADE SOME SLIGHT ADJUSTMENTS BASED ON LATEST INFORMATION...THOUGH MODEL DIFFERENCES STILL EXIST FRIDAY ONWARD. DEGREE OF AMPLIFICATION OF FLOW IN QUESTION...BUT EITHER WAY HEIGHTS/THICKNESSES WILL RISE THIS THE WEEKEND WHICH SHOULD LEAD TO AREA WIDE 40S BY SUNDAY...WITH NIGHTS STAYING ABOVE FREEZING FOR MOST IF NOT ALL OF AREA SATURDAY NIGHT ONWARD. IF PRECIPITATION RUNS WELL OUT AHEAD DURING TRANSITION PERIOD SATURDAY SUCH AS DEPICTED IN GFS...SOME QUESTION AS TO WHICH TYPE IT WOULD BE /LIGHT WINTRY MIX NOT OUT OF QUESTION/...BUT AT THIS POINT AS PER ECMWF WE DO NOT HAVE CHANCE POPS IN REGION UNTIL SAT NIGHT-SUNDAY DURING WHICH P-TYPE WOULD BE ALMOST EXCLUSIVELY RAIN. PREVIOUS DISCUSSION... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... 12Z UPDATE... LAKE EFFECT SNOW BAND OFF OF LAKE ONTARIO IS MAIN FEATURE OF INTEREST. WINDS ARE BEGINNING TO VEER W TO EVEN WNW WITH PASSAGE OF A WAVE. THIS HAS SENT LAKE EFFECT BAND SOUTHWARD TO NY THRUWAY CORRIDOR...INCLUDING KRME AND KSYR. IFR CONDITIONS SHOULD BE DONE FOR KRME BY 12Z /THOUGH MVFR -SHSN STILL POSSIBLE/...BUT KSYR WILL BE IN-AND-OUT OF IT MUCH OF THIS MORNING. AS BAND LIFTS BACK NORTHWARD WITH BACKING OF WINDS THIS EVENING...IFR -SHSN AGAIN POSSIBLE FOR A TIME AT KRME. FOR REMAINDER OF CENTRAL NY TERMINALS...GREAT LAKES MOISTURE WILL MAINTAIN MVFR OR LOW END VFR CIGS. KAVP MEANWHILE WILL REMAIN VFR TODAY THROUGH EVENING. A WEAK SYSTEM WILL CLIP THE AREA DURING PREDAWN HOURS TUESDAY...LOWERING CIGS TO MVFR FOR A FEW TERMINALS 09Z-12Z...ESPECIALLY KAVP/KBGM WHERE -SN WILL ALSO DEGRADE VIS. IFR NOT OUT OF THE QUESTION. OUTLOOK... TUE...VFR-MVFR WITH CHC IFR TUE MORNING AS SYSTEM SKIMS THE AREA...ESPECIALLY AVP AND BGM. WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP/MLJ SHORT TERM...DJP LONG TERM...MDP/MSE AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
908 AM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 9 AM UPDATE... MAIN FOCUS IS ON LES BAND LATE THIS MRNG. IN GENERAL...THE BAND HAS EXHIBITED A SLOW SWD DRIFT THE PAST FEW HRS...AND ITS APPEARANCE HAS BECOME A BIT MORE RAGGED SINCE ABT 13Z. WE EXPECT BOTH OF THESE TRENDS TO HOLD THROUGH MIDDAY/EARLY AFTN...AS THE LOW-LVL FLOW SLOWLY VEERS...AND INCREASING TERRESTRIAL INSTAB DETRACTS FROM BAND ORGANIZATION. WHERE THE BAND IS MOST PERSISTENT THROUGH 16-17Z...WE`RE INDICATING LOCALIZED 1-1.5" AMTS. BASED ON RECENT REPORTS AND WEB CAM SHOTS FROM IN AND ARND KSYR...BRIEF SHSN/+SHSN ARE ONLY BEING EXPERIENCED RIGHT UNDERNEATH THE MIDDLE OF THE BAND...WITH INTENSITY QUICKLY TAPERING OFF OUTSIDE OF THE BAND CENTERLINE. THIS AFTN...THERE IS GOOD AGREEMENT AMONGST OUR NEAR-TERM HI RES MODELS (4-12 KM NAM...HRRR...AND OUR LOCAL WRF) THAT THE BAND (ALBEIT IN A "BROKEN UP" STATE) WILL BEGIN TO DRIFT BACK NWD...LIKELY REACHING NRN ONEIDA BY 18-21Z. AS A RESULT...WE HAVE A SMATTERING OF ADDTNL ACCUMS THIS AFTN IN FAR NRN ONONDAGA...NRN MADISON...AND ONEIDA (MOSTLY LESS THAN AN INCH). OUTSIDE OF LES IMPACTED AREAS...JUST A FEW FLRYS...AT WORST...ARE ANTICIPATED THROUGH THE DAY. GENERALLY CLEAR SKIES ACRS NE PA ATTM...SHOULD BECOME PARTLY SUNNY BY EARLY AFTN...WITH SOME MOISTURE STILL TRAPPED UNDERNEATH A SUBSIDENCE INVERSION (SHOWN ON KBUF...KALY...AND KPIT 12Z SNDGS). NEAR-TERM TEMP/DEW PT GRIDS WERE TWEAKED JUST A LTL...WITH OUR AFTN MAX TEMP FCST LOOKING SOLD ATTM. PREV DISC... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFORE THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. 3 AM UPDATE... LATEST RAPID REFRESH MODEL DEPICTS THE LAKE SNOW BAND MOVING BACK INTO ONEIDA COUNTY OVER THE NEXT FEW HOURS, AND RADAR CONFIRMS THIS TREND. A FRONTAL SYSTEM / TROF WILL CROSS THE REGION, CAUSING WINDS TO VEER AND THE LAKE BAND TO SHIFT SOUTHWARD THROUGH SUNRISE. SNOWFALL RATES OF AROUND AN INCH PER HOUR CAN BE EXPECTED WITHIN THE BAND. DRIER AIR AND INCREASING SHEAR BEHIND THE FRONT WILL UNDERMINE THE LAKE BAND BY EARLY AFTERNOON, AND CAUSE THE ACTIVITY TO WEAKEN. LIGHT LAKE SNOWS WILL LIKELY CONTINUE THROUGH LATE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MADE SOME SLIGHT ADJUSTMENTS BASED ON LATEST INFORMATION...THOUGH MODEL DIFFERENCES STILL EXIST FRIDAY ONWARD. DEGREE OF AMPLIFICATION OF FLOW IN QUESTION...BUT EITHER WAY HEIGHTS/THICKNESSES WILL RISE THIS THE WEEKEND WHICH SHOULD LEAD TO AREA WIDE 40S BY SUNDAY...WITH NIGHTS STAYING ABOVE FREEZING FOR MOST IF NOT ALL OF AREA SATURDAY NIGHT ONWARD. IF PRECIPITATION RUNS WELL OUT AHEAD DURING TRANSITION PERIOD SATURDAY SUCH AS DEPICTED IN GFS...SOME QUESTION AS TO WHICH TYPE IT WOULD BE /LIGHT WINTRY MIX NOT OUT OF QUESTION/...BUT AT THIS POINT AS PER ECMWF WE DO NOT HAVE CHANCE POPS IN REGION UNTIL SAT NIGHT-SUNDAY DURING WHICH P-TYPE WOULD BE ALMOST EXCLUSIVELY RAIN. PREVIOUS DISCUSSION... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... 12Z UPDATE... LAKE EFFECT SNOW BAND OFF OF LAKE ONTARIO IS MAIN FEATURE OF INTEREST. WINDS ARE BEGINNING TO VEER W TO EVEN WNW WITH PASSAGE OF A WAVE. THIS HAS SENT LAKE EFFECT BAND SOUTHWARD TO NY THRUWAY CORRIDOR...INCLUDING KRME AND KSYR. IFR CONDITIONS SHOULD BE DONE FOR KRME BY 12Z /THOUGH MVFR -SHSN STILL POSSIBLE/...BUT KSYR WILL BE IN-AND-OUT OF IT MUCH OF THIS MORNING. AS BAND LIFTS BACK NORTHWARD WITH BACKING OF WINDS THIS EVENING...IFR -SHSN AGAIN POSSIBLE FOR A TIME AT KRME. FOR REMAINDER OF CENTRAL NY TERMINALS...GREAT LAKES MOISTURE WILL MAINTAIN MVFR OR LOW END VFR CIGS. KAVP MEANWHILE WILL REMAIN VFR TODAY THROUGH EVENING. A WEAK SYSTEM WILL CLIP THE AREA DURING PREDAWN HOURS TUESDAY...LOWERING CIGS TO MVFR FOR A FEW TERMINALS 09Z-12Z...ESPECIALLY KAVP/KBGM WHERE -SN WILL ALSO DEGRADE VIS. IFR NOT OUT OF THE QUESTION. OUTLOOK... TUE...VFR-MVFR WITH CHC IFR TUE MORNING AS SYSTEM SKIMS THE AREA...ESPECIALLY AVP AND BGM. WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP/MLJ SHORT TERM...DJP LONG TERM...MDP/MSE AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
647 AM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFORE THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. 3 AM UPDATE... LATEST RAPID REFRESH MODEL DEPICTS THE LAKE SNOW BAND MOVING BACK INTO ONEIDA COUNTY OVER THE NEXT FEW HOURS, AND RADAR CONFIRMS THIS TREND. A FRONTAL SYSTEM / TROF WILL CROSS THE REGION, CAUSING WINDS TO VEER AND THE LAKE BAND TO SHIFT SOUTHWARD THROUGH SUNRISE. SNOWFALL RATES OF AROUND AN INCH PER HOUR CAN BE EXPECTED WITHIN THE BAND. DRIER AIR AND INCREASING SHEAR BEHIND THE FRONT WILL UNDERMINE THE LAKE BAND BY EARLY AFTERNOON, AND CAUSE THE ACTIVITY TO WEAKEN. LIGHT LAKE SNOWS WILL LIKELY CONTINUE THROUGH LATE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MADE SOME SLIGHT ADJUSTMENTS BASED ON LATEST INFORMATION...THOUGH MODEL DIFFERENCES STILL EXIST FRIDAY ONWARD. DEGREE OF AMPLIFICATION OF FLOW IN QUESTION...BUT EITHER WAY HEIGHTS/THICKNESSES WILL RISE THIS THE WEEKEND WHICH SHOULD LEAD TO AREAWIDE 40S BY SUNDAY...WITH NIGHTS STAYING ABOVE FREEZING FOR MOST IF NOT ALL OF AREA SATURDAY NIGHT ONWARD. IF PRECIPITATION RUNS WELL OUT AHEAD DURING TRANSITION PERIOD SATURDAY SUCH AS DEPICTED IN GFS...SOME QUESTION AS TO WHICH TYPE IT WOULD BE /LIGHT WINTRY MIX NOT OUT OF QUESTION/...BUT AT THIS POINT AS PER ECMWF WE DO NOT HAVE CHANCE POPS IN REGION UNTIL SAT NIGHT-SUNDAY DURING WHICH P-TYPE WOULD BE ALMOST EXCLUSIVELY RAIN. PREVIOUS DISCUSSION... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... 12Z UPDATE... LAKE EFFECT SNOW BAND OFF OF LAKE ONTARIO IS MAIN FEATURE OF INTEREST. WINDS ARE BEGINNING TO VEER W TO EVEN WNW WITH PASSAGE OF A WAVE. THIS HAS SENT LAKE EFFECT BAND SOUTHWARD TO NY THRUWAY CORRIDOR...INCLUDING KRME AND KSYR. IFR CONDITIONS SHOULD BE DONE FOR KRME BY 12Z /THOUGH MVFR -SHSN STILL POSSIBLE/...BUT KSYR WILL BE IN-AND-OUT OF IT MUCH OF THIS MORNING. AS BAND LIFTS BACK NORTHWARD WITH BACKING OF WINDS THIS EVENING...IFR -SHSN AGAIN POSSIBLE FOR A TIME AT KRME. FOR REMAINDER OF CENTRAL NY TERMINALS...GREAT LAKES MOISTURE WILL MAINTAIN MVFR OR LOW END VFR CIGS. KAVP MEANWHILE WILL REMAIN VFR TODAY THROUGH EVENING. A WEAK SYSTEM WILL CLIP THE AREA DURING PREDAWN HOURS TUESDAY...LOWERING CIGS TO MVFR FOR A FEW TERMINALS 09Z-12Z...ESPECIALLY KAVP/KBGM WHERE -SN WILL ALSO DEGRADE VIS. IFR NOT OUT OF THE QUESTION. OUTLOOK... TUE...VFR-MVFR WITH CHC IFR TUE MORNING AS SYSTEM SKIMS THE AREA...ESPECIALLY AVP AND BGM. WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP SHORT TERM...DJP LONG TERM...MDP/MSE AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
632 AM EST MON NOV 26 2012 .SYNOPSIS... LAKE SNOWS WILL CONTINUE ACROSS NORTHERN NY TODAY, BEFORE TAPERING OFF LATER THIS EVENING. A LOW PRESSURE SYSTEM WILL RIDE UP THE MID ATLANTIC EARLY TUESDAY MORNING. THIS STORM WILL BRING A QUICK 1 TO 2 INCHES OF SNOW ACCUMULATION TO PENNSYLVANIA, MAINLY ALONG AND SOUTH OF INTERSTATE 84. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LAKE SNOW BAND HAS PUSHED SOUTH QUICKER THAN MODELS FIRST FORECAST. BUFKIT RAP PROFILE SUGGESTS THE BAND WILL BE ALIGNED ACROSS NORTHERN ONONDAGA AND NORTHERN MADISON COUNTIES THROUGH THE NEXT SEVERAL HOURS. THEREFOR THE LES WARNING FOR N ONEIDA HAS BEEN DROPPED, AND WE HAVE INCREASED SNOWFALL TOTALS FOR NORTHERN ONONDAGA-MADISON TO 1-2 INCHES OF NEW SNOW BY EARLY AFTERNOON. 3 AM UPDATE... LATEST RAPID REFRESH MODEL DEPICTS THE LAKE SNOW BAND MOVING BACK INTO ONEIDA COUNTY OVER THE NEXT FEW HOURS, AND RADAR CONFIRMS THIS TREND. A FRONTAL SYSTEM / TROF WILL CROSS THE REGION, CAUSING WINDS TO VEER AND THE LAKE BAND TO SHIFT SOUTHWARD THROUGH SUNRISE. SNOWFALL RATES OF AROUND AN INCH PER HOUR CAN BE EXPECTED WITHIN THE BAND. DRIER AIR AND INCREASING SHEAR BEHIND THE FRONT WILL UNDERMINE THE LAKE BAND BY EARLY AFTERNOON, AND CAUSE THE ACTIVITY TO WEAKEN. LIGHT LAKE SNOWS WILL LIKELY CONTINUE THROUGH LATE AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... OPEN WAVE IN UL PATTERN WILL AID A RATHER DIFFUSE LOW PRESSURE STORM SYSTEM SLIDING UP THE MID ATLANTIC REGION TUESDAY MORNING. EURO/NAM/GFS IN PRETTY GOOD AGREEMENT, THOUGH NAM APPEARS TOO AGGRESSIVE IN NORTHWARD EXTENT OF PRECIP SHIELD. THE SCENARIO LOOKS TO BE A QUICK HITTER, WITH PORTIONS OF NE PA (MAINLY ALONG AND SOUTH OF I-84) PICKING UP AN INCH OR AN INCH AND A HALF OF SNOW TUESDAY MORNING. THE SYSTEM SLIDES EASTWARD WITH MUCH DRIER AIR BRINGING AN END TO THE SNOW SHOWERS BY NOON...IF NOT SOONER. STICKING TO A TIGHT GRADIENT FOR THE PRECIPITATION PATTERN, WITH ONLY CHC POPS ALONG THE SOUTHERN TIER OF NY. SOME WEAK LAKE ACTIVITY IS ANTICIPATED OVER THE NORTHERN FA TUESDAY AND TUESDAY EVENING, AFTER WINDS SHIFT TO THE WEST-NORTHWEST. HIGH PRESSURE WILL CONTROL THE WEATHER WEDNESDAY, WITH A CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS OVER THE NORTHERN 2/3 OF THE FA. && .LONG TERM /THURSDAY THROUGH SUNDAY/... MADE SOME SLIGHT ADJUSTMENTS BASED ON LATEST INFORMATION...THOUGH MODEL DIFFERENCES STILL EXIST FRIDAY ONWARD. DEGREE OF AMPLIFICATION OF FLOW IN QUESTION...BUT EITHER WAY HEIGHTS/THICKNESSES WILL RISE THIS THE WEEKEND WHICH SHOULD LEAD TO AREAWIDE 40S BY SUNDAY...WITH NIGHTS STAYING ABOVE FREEZING FOR MOST IF NOT ALL OF AREA SATURDAY NIGHT ONWARD. IF PRECIPITATION RUNS WELL OUT AHEAD DURING TRANSITION PERIOD SATURDAY SUCH AS DEPICTED IN GFS...SOME QUESTION AS TO WHICH TYPE IT WOULD BE /LIGHT WINTRY MIX NOT OUT OF QUESTION/...BUT AT THIS POINT AS PER ECMWF WE DO NOT HAVE CHANCE POPS IN REGION UNTIL SAT NIGHT-SUNDAY DURING WHICH P-TYPE WOULD BE ALMOST EXCLUSIVELY RAIN. PREVIOUS DISCUSSION... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... 06Z UPDATE... LAKE EFFECT SNOW BAND OFF OF LAKE ONTARIO IS MAIN FEATURE OF INTEREST. WINDS THAT BACKED TO WSW AHEAD OF INCOMING WAVE IN THE EVENING...WILL BEGIN TO VEER TO W TO EVEN WNW WITHIN A FEW HOURS AS WAVE PASSES. THIS WILL SEND LAKE ONTARIO BAND ACROSS NY THRUWAY CORRIDOR INCLUDING KRME AND KSYR...DEGRADING CONDITIONS INTO IFR AT TIMES THROUGH ABOUT 15Z-18Z...BEFORE BAND BREAKS UP TO MORE CELLULAR IN NATURE. FOR REMAINDER OF CENTRAL NY TERMINALS...GREAT LAKES MOISTURE WILL MAINTAIN MVFR OR LOW END VFR CIGS AND OCCASIONAL FLURRIES BUT WITHOUT SIGNIFICANT VIS DEGRADATION. KAVP MEANWHILE WILL REMAIN VFR. MOST TERMINALS BY LATE IN THE DAY LOSE MVFR CIG...HOWEVER...CIGS WILL START LOWERING AGAIN TOWARDS 06Z AS NEXT SYSTEM APPROACHES FROM THE SOUTHWEST. OUTLOOK... TUE...VFR-MVFR WITH CHC IFR AS STORM SYSTEM SLIDES JUST TO THE SOUTH...ESPECIALLY AVP AND BGM. WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP NEAR TERM...DJP SHORT TERM...DJP LONG TERM...MDP/MSE AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1253 AM EST MON NOV 26 2012 .SYNOPSIS... LAKE EFFECT SNOWS WILL IMPACT THE TUG HILL PLATEAU REGION TONIGHT...AND THEN DROP BACK SOUTH TO COVER MORE OF CENTRAL NEW YORK WITH SNOW SHOWERS FOR THE FIRST HALF OF MONDAY. SNOW SHOWERS DIMINISH FOR A TIME MONDAY AFTERNOON...BEFORE A FAST MOVING LOW PRESSURE SYSTEM BRINGS A PERIOD OF LIGHT SNOW AND FLURRIES TO NORTHERN PENNSYLVANIA AND SOUTHERN NEW YORK LATE MONDAY NIGHT AND EARLY TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MIDWEEK. && .NEAR TERM /THROUGH TODAY/... 1030 PM UPDATE... LAKE BAND CONTINUING TO MOVE NORTH THIS HR AS EVIDENCED ON LATEST RADAR TRENDS. FURTHER SOUTH...GENERAL LIGHT SYNOPTIC SNOW CONTINUING TO ALSO FALL ACROSS PORTIONS OF THE FINGER LAKES AND SUSQUEHANNA VALLEY REGIONS OF CENTRAL NEW YORK. SYNOPTIC ACTIVITY IS BEING FORCED BY THE COMBINATION OF A WEAK SHEARED OUT SHORTWAVE TRAVELING OVER THE REGION AND INCREASING WARM AIR ADVECTION IN ADVANCE OF A WEAK SFC LOW TRAVELING THROUGH SOUTHERN CANADA. THAT SAID...SYNOPTIC ACTIVITY WILL COME TO AN END IN THE NEXT FEW HRS WITH ALL ATTENTION REMAINING ON LAKE EFFECT ACTIVITY EAST OF LAKE ONTARIO. 18Z LOCALLY RUN WRF AND LATEST RAPID REFRESH (FORMALLY THE RUC) ACCURATELY SHOWING THE NORTHWARD MOVEMENT OF THE BAND OVER THE PAST FEW HRS. THIS IS OCCURRING AS THE LOW-LEVEL FLOW BACKS IN ADVANCE OF THE AFOREMENTIONED SFC LOW TRAVELING TO OUR NORTH. UPSTREAM OBSERVATIONS ACROSS SOUTHERN ONTARIO AND EASTERN MI SHOWING A GRADUAL WIND SHIFT TO THE WNW BEHIND THE LOW. GIVEN THIS SCENARIO...WE EXPECT THE LAKE BAND TO GRADUALLY BEGIN SHIFTING SOUTH AFTER 09Z AS WINDS VEER BEHIND THE FEATURE. ONCE THIS OCCURS...LAKE BAND CHARACTERIZED BY HOURLY SNOWFALL RATES OF OVER 1"/HR WILL MOVE BACK INTO NORTHERN ONEIDA COUNTY WHERE ADDITIONAL SNOWFALL MAY PUSH STORM TOTALS OVER THE 10-12" MARK. SNOWS WILL CONTINUE THROUGH A GOOD PORTION OF THE MORNING HRS ACROSS CENTRAL AND NORTHERN ONEIDA COUNTY BEFORE DRIER AIR MOVES INTO THE REGION TOWARDS MIDDAY...ULTIMATELY DECREASING LAKE EFFECT INTENSITY AND ORGANIZATION. REMAINDER OF THE FCST AREA OUTSIDE OF LAKE ACTIVITY SHOULD SEE MAINLY DRY CONDITIONS THROUGH THE DAY ON MONDAY WITH HIGH TEMPS TOPPING OUT IN THE MIDDLE TO UPPER 30S. 745 PM UPDATE... SINGLE LAKE EFFECT BAND EAST OF LAKE ONTARIO ONGOING THIS HR WITH RADAR INDICATIONS SUGGESTING BAND IS BEGINNING LIFT NORTH AS EXPECTED. NORTHWARD SHIFT IS THE RESULT OF BACKING LOW-LEVEL FLOW IN ADVANCE OF A WEAK AREA OF LOW PRESSURE NOW MOVING THROUGH SOUTHERN ONTARIO. WITH TIME OVERNIGHT...MAIN BAND IS AGAIN EXPECTED TO BEGIN DRIFTING SOUTH AS WINDS BEGIN VEERING BEHIND DEPARTING SFC WAVE. LATEST MODEL TRENDS FROM BOTH THE LOCALLY RUN WRF AND RR SHOW SOUTHWARD MIGRATION AFTER 06Z FAIRLY WELL AS FLOW AGAIN AGAIN BECOMES WEST-NORTHWESTERLY. NO RECENT SNOWFALL REPORTS HOWEVER REPORTS EARLIER THIS EVENING INDICATED THAT SNOWFALL TOTALS WERE RAPIDLY APPROACHING 6". AS THE BAND DRIFTS SOUTH INTO THE REGION AGAIN AFTER MIDNIGHT...HOURLY SNOWFALL RATES OF 2-3"/HR WILL BE POSSIBLE UNDER THE MOST INTENSE PART OF THE BAND...BRINGING STORM TOTAL SNOWFALLS IN THE 10-15" RANGE BEFORE ALL IS SAID AND DONE EARLY MON AFTERNOON. WILL CONTINUE TO ADJUST SNOWFALL FCST AS NEW MODEL GUIDANCE COMES IN. ELSEWHERE...REGIONAL RADARS DEPICTING -SN ACROSS MUCH OF CENTRAL NY AS ASSOCIATED UPPER SHORTWAVE MOVES OVER THE REGION. LITTLE TO NO SNOW ACCUMULATIONS ARE EXPECTED WITH THIS ACTIVITY HOWEVER AS ALL ACCUMULATIONS WILL BE CONFINED TO THE SINGLE LAKE BAND EAST OF LAKE ONTARIO. 445 PM UPDATE... HAVE RECEIVED A FEW REPORTS OF OVER SIX INCHES OF SNOW ACROSS NORTHERN PORTIONS OF ONEIDA COUNTY. LATEST RADAR TRENDS SHOW A WELL DEVELOPED LAKE BAND EXTENDING INLAND FROM LAKE ONTARIO...WITH LITTLE INDICATION SNOWS WILL STOP ANYTIME SOON. BAND WILL LIKELY LIFT NORTH OF THE AREA FOR A TIME LATER THIS EVENING BEFORE SHIFTING SOUTH ACROSS NORTHERN ONEIDA COUNTY ONCE AGAIN AS WINDS AGAIN BECOME WESTERLY AFTER MIDNIGHT. THAT SAID...HAVE DECIDED TO UPGRADE THE ADVISORY TO A WARNING AS ADDITIONAL ROUNDS OF SNOW COMBINED WITH SNOW THAT IS OCCURRING NOW WILL LIKELY PUSH ACCUMULATIONS ABOVE WARNING CRITERIA. NEW WSW ALREADY POSTED. WILL CONTINUE TO MONITOR. PREVIOUS NEAR TERM DISCUSSION... MADE SEVERAL CHANGES TO THE FCST FOR TODAY THROUGH TONIGHT. NAMELY HAD TO ADJUST POPS HIGHER AS UPPER WAVE CAME IN FROM THE WEST FOR A HIGH OCCURRENCE/LOW QPF EVENT WITH GENERALLY LIGHT SNOW/FLURRIES ACROSS THE REGION. WITHIN THE GENERAL LIGHT SNOW AREA REMAINS THE EMBEDDED LAKE BANDS...AND THE ONEIDA CENTRIC BAND WAS BECOMING RE- ESTABLISHED ON A 280 FLOW PATTERN THIS AFTERNOON. SOME REPORTS OF 2-3 INCHES HAVE BEEN RECEIVED FROM ROME NORTHWARD SINCE THIS MORNING. BAND SHOULD BE ABLE TO PRODUCE ANOTHER FEW INCHES THIS AFTERNOON AND EARLY EVENING BEFORE PULLING JUST NORTH OF THE COUNTY LATER IN THE EVENING. FOLLOWED OUR LOCAL WRF MODEL IN REGARDS TO TIMING AND PLACEMENT OF LIFT/MOISTURE AND QPF FIELDS...ALTHOUGH NAM12 AND RAP MODEL BUFKIT FIELDS ARE COMPARABLE. THE BAND THEN LOOKS TO COME BACK IN JUST PRIOR TO DAYBREAK MONDAY WITH ANOTHER FEW INCHES POSSIBLE. SHEAR ALONG WITH WEAKENING FLOW AND DIURNAL DISRUPTION OF THE LAKE INSTABILITY PROCESSES ALLOW FOR WEAKENING MONDAY AFTERNOON WITH NOMINAL ACCUMS. SEE LITTLE VARIATION IN TEMPERATURES WITH LOWS IN THE UPR 20S TONIGHT AND HIGHS MONDAY GENERALLY MID 30S. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... NEXT ITEM TO FOCUS ON WILL BE APPROACHING OPEN WAVE AND WEAK LOW PRESSURE ON MONDAY NIGHT AND EARLY TUESDAY. THIS LOOKS TO BE A RATHER MINIMAL EVENT WITH SNOW BREAKING OUT OVER THE LOWER OH/TN VALLEY REGION DUE TO ISENTROPIC LIFT AHEAD OF THE UPPER WAVE WHICH THEN LIFTS NORTH INTO MAINLY THE SOUTHERN HALF OF NY AND NEPA. GFS/NAM IN REASONABLE AGREEMENT THAT WE NEED TO SPEED UP TIMING BY A GOOD 6 HOURS AS WAA PRECIP DOES TEND TO DEVELOP QUICKER AND THESE TRENDS SUPPORT THAT. WILL BRING IN LIGHT SNOW BETWEEN 06Z-12Z TUESDAY...WITH A QUICK HITTING EVENT THAT APPEARS TO BE OUT OF THE PICTURE BY EARLY AFTERNOON. THIS...ALONG WITH MARGINAL TEMPERATURES AND MINIMAL LIFT SHOULD BE A LIGHT EVENT WITH NOMINAL ACCUMULATIONS RANGING FROM A DUSTING TO AN INCH...POSSIBLY 2 INCHES IN THE MOUNTAINS OF NEPA. THE NORTHERN EXTENT LOOKS TO BE AROUND THE SOUTHERN TIER OF NY...WITH POSSIBLY A FEW FLURRIES UP NORTH. HIGH PRESSURE THEN BUILDS IN FROM THE SOUTHWEST...BUT BROAD CYCLONIC FLOW ALOFT AND INCREASING LOW LEVEL MOISTURE ON NWLY LOWER ATMOSPHERE FLOW SHOULD SPELL A BROAD AREA OF FLURRIES DEVELOPING BY WEDNESDAY AFTERNOON. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... GFS/ECMWF IN GOOD AGREEMENT THROUGH THURSDAY... THEN SOME DIFFERENCES DEVELOP WITH THE NEXT SYSTEM APPROACHING THE AREA FROM THE MIDWEST. WEDNESDAY NIGHT THROUGH THURSDAY WILL BE COLD WITH SCATTERED SNOW SHOWERS NEAR LAKE ONTARIO... OTHERWISE DRY. THE GFS BRINGS PRECIPITATION ASSOCIATED WITH THE NEXT SYSTEM FRIDAY NIGHT AND SATURDAY... WHILE THE ECMWF IS MUCH SLOWER AND MORE AMPLIFIED WITH THIS SYSTEM... NOT BRINGING ANY PRECIPITATION INTO THE AREA UNTIL AROUND SUNDAY. AT THIS POINT HAVE GONE WITH THE HPC SCENARIO WHICH FAVORS THE SLOWER ECMWF. BASED ON THIS HAVE KEPT PRECIPITATION OUT OF THE FORECAST THROUGH SATURDAY. TEMPERATURES THURSDAY THROUGH SATURDAY WILL BE NEAR TO SLIGHTLY BELOW NORMAL... WITH HIGHS MAINLY IN THE 30S AND LOWS IN THE 20S. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... 06Z UPDATE... LAKE EFFECT SNOW BAND OFF OF LAKE ONTARIO IS MAIN FEATURE OF INTEREST. WINDS THAT BACKED TO WSW AHEAD OF INCOMING WAVE IN THE EVENING...WILL BEGIN TO VEER TO W TO EVEN WNW WITHIN A FEW HOURS AS WAVE PASSES. THIS WILL SEND LAKE ONTARIO BAND ACROSS NY THRUWAY CORRIDOR INCLUDING KRME AND KSYR...DEGRADING CONDITIONS INTO IFR AT TIMES THROUGH ABOUT 15Z-18Z...BEFORE BAND BREAKS UP TO MORE CELLULAR IN NATURE. FOR REMAINDER OF CENTRAL NY TERMINALS...GREAT LAKES MOISTURE WILL MAINTAIN MVFR OR LOW END VFR CIGS AND OCCASIONAL FLURRIES BUT WITHOUT SIGNIFICANT VIS DEGRADATION. KAVP MEANWHILE WILL REMAIN VFR. MOST TERMINALS BY LATE IN THE DAY LOSE MVFR CIG...HOWEVER...CIGS WILL START LOWERING AGAIN TOWARDS 06Z AS NEXT SYSTEM APPROACHES FROM THE SOUTHWEST. OUTLOOK... TUE...VFR-MVFR WITH CHC IFR AS STORM SYSTEM SLIDES JUST TO THE SOUTH...ESPECIALLY AVP AND BGM. WED...VFR-MVFR WITH CHC IFR IN LAKE SNOW SHOWERS...MAINLY KSYR- KRME. THU/FRI...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR NYZ009. && $$ SYNOPSIS...JAB NEAR TERM...CMG/JAB SHORT TERM...JAB LONG TERM...MSE AVIATION...MDP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
911 PM CST TUE NOV 27 2012 .DISCUSSION... CLOUD AND THE RESULTING TEMPS CONTINUE TO BE A HEADACHE TONIGHT. SAT LOOPS SHOW HOLES IN THE STRATUS THAT MOVED INTO THE NORTHERN CWA HAVE BEGUN TO FILL IN...BUT MORE CLEAR SPOTS ARE DEVELOPING NEAR THE CANADIAN BORDER. TEMPS IN THAT AREA ARE ALREADY IN THE SINGLE DIGITS AND THINK THERE SHOULD BE ENOUGH CLEAR SKIES CONTINUING TO SEE TEMPS DROP BELOW ZERO BY MORNING. FURTHER SOUTH...THE HRRR AND RAP SHOW THAT MUCH OF THE CLOUD COVER CONTINUES TO STICK AROUND FROM THE DEVILS LAKE BASIN SOUTHEASTWARD INTO THE LAKE REGION OF MN. COMPARING SAT LOOP TO MODELS THEY MAY EVEN BE OVERDOING THE CLEARING IN OUR NORTH AND EAST. STILL...THINK THAT THAT REGION WILL HAVE THE BEST SHOT OF CLEARING OUT WHILE THE SOUTH AND WEST WILL STAY PRETTY CLOUDY. ADJUSTED CLOUD GRIDS ACCORDINGLY AND BUMPED UP TEMPS IN THE SOUTH AND WEST JUST A BIT. DID NOT GO TOO HIGH WITH OVERNIGHT LOWS AS ANY BREAK IN THE CLOUDS WILL ALLOW READINGS TO DROP LIKE A ROCK. && .AVIATION... SAT LOOP SHOWS SOME CLEARING JUST NORTH OF KDVL...KGFK...AND KTVF. HOWEVER...A LOT OF FILLING IN IS APPARENT. WILL KEEP AN EYE ON CLEARING TRENDS BUT AT LEAST KFAR MAY STAY MVFR THROUGH OUT THE NIGHT. SITES FURTHER NORTH COULD SEE SOME BREAKS WITH RECOVERY TO VFR AT LEAST FOR A SHORT TIME. THINK THAT STRATUS WILL GRADUALLY BREAK UP BY MID MORNING WITH HIGHER LEVEL CEILINGS MOVING IN AND VFR CONDITIONS. LIGHT AND VARIABLE WINDS WILL EVENTUALLY PICK UP OUT OF THE SOUTH BY 8 TO 10 KTS. && .PREV DISCUSSION... /ISSUED 246 PM CST TUE NOV 27 2012/ SHORT TERM... CHALLENGES FOR THE FORECAST INCLUDE CLOUD TRENDS AND THEIR EFFECT ON MIN TEMPS...ESPECIALLY TONIGHT... AND DEGREE OF WARMING BEFORE FROPA WEDNESDAY EVENING AND SUBSEQUENT TEMP REBOUND FRIDAY. MODELS IN GENERAL AGREEMENT AND USED A BLEND OVERALL FOR TEMPS LEANING TOWARD THE COLDER GEM ACROSS THE AREA WITH CLEARER SKIES THIS EVENING BEFORE BLENDING IN THE BETTER PERFORMING ECMWF GUIDANCE THEREAFTER. PERSISTENT STRATUS DECK THIS AFTERNOON PRODUCING FLURRIES/-SN ACROSS THE CWFA AS WELL AS UPSTREAM IN N ND AND SW MANITOBA SHOWS UP WELL WITH RESPECT TO LOW CONDENSATION PRESSURE DEFICITS AT 925MB IN THE 12Z NAM. ALSO LINING UP WELL NEAR THE MODEL CALCULATED LCL WHERE CONVECTIVE TEMPS ARE IN THE MID TEENS TODAY. EXPECTING THIS CLOUD DECK TO ERODE THIS EVENING AS DRIER AND COLDER AIR CONTINUE TO FILTER IN WITH BUILDING SFC HIGH PRESSURE. SOME STRATUS DECK CURRENTLY PRESENT UNDER THE SFC HIGH IN SASKATCHEWAN AND MANITOBA ALONG WITH MID CLOUD IS EXPECTED TO LIMIT IDEAL RADIATIONAL COOLING...CURRENT THINKING IS THAT IT WILL BE INTERMITTENT AT BEST OVERNIGHT. MODEL RHS FIELDS INDICATE THE MOST LIKELY PLACE FOR THE BEST COOLING TO BE IN THE N RRV AND NW MN WHERE SCT TO BKN CIGS ARE ALREADY BEING OBSERVED. THIS ALIGNS WITH THE COLDEST MORNING FORECASTED TEMPS... 0 TO 10 BELOW WITH SINGLE DIGITS ABOVE ELSEWHERE. FOR WEDNESDAY SFC HIGH QUICKLY MOVES SE WITH RETURN FLOW SETTING UP AND WAA. WITH 925MB TEMPS INCREASING TO 2C SOUTH TO -4 NORTH BY 00Z THURS SHOULD SEE HIGH TEMPS IN THE 20S TO 30S SOUTH. SHORT LIVED WARM UP THOUGH AS DRY FROPA MOVES ACROSS THE REGION WEDNESDAY EVENING. THURSDAY SHOULD BE ANOTHER COOL DAY AS SFC HIGH TRACKS ACROSS MANITOBA PROVIDING E TO NE WINDS AND WITH 925MB TEMPS IN THE -5 TO -15 DEGREE RANGE WITH HIGHS IN THE TEENS AND 20S. THURSDAY NIGHT RETURN FLOW ONCE AGAIN DEVELOPS WITH A CHC FOR SN AS WAA MOVES ACROSS THE NORTHERN VALLEY WITH DAYTIME HIGHS FRIDAY EXPECTED TO BE IN THE 20S NORTH AND 30S SOUTH...ESPECIALLY OVER THE SNOW FREE AREAS. LONG TERM (FRI NIGHT-TUE)... A SOMEWHAT MORE ZONAL SOUTHWEST FLOW TO START OUT WITH WHICH WILL PUSH A WEAK SFC LOW ACROSS THE AREA FRI NIGHT/SAT. MOST PCPN WITH THIS SYSTEM SHOULD BE ACROSS THE NORTH AND IT SHOULD STAY COLD ENOUGH FOR JUST LIGHT SNOW. SUNDAY STILL LOOKS PRETTY QUIET BUT THE MODELS ARE NOT IN GOOD AGREEMENT IN THEIR THERMAL FIELDS (12Z EC NOW COLDER). NEXT SYSTEM PUSHES OUT MONDAY INTO TUE WITH THE SAME TEMP DISCREPANCIES. 12Z GFS ALSO HAS A MUCH DEEPER/SLOWER SFC LOW THAN THE ECMWF WHICH WOULD BE A WINDIER SCENARIO WITH A BIT MORE LINGERING LIGHT SNOW. WITH THE THERMAL DIFFERENCES IN THE MODELS KEPT MORE OF A GENERIC LIGHT RAIN OR LIGHT SNOW MENTION FOR NOW. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
302 PM CST MON NOV 26 2012 .SHORT TERM... /TONIGHT THROUGH THURSDAY/ THE PRIMARY CHALLENGE FOR THE SHORT TERM PERIOD WILL BE A LIGHT SNOW EVENT EXPECTED TO IMPACT NORTHERN ZONES. THIS SYSTEM IS JUST BEGINNING TO EVOLVE...AND THE NAM/RUC SOLUTION HAVE HAD A DECENT HANDLE ON IT...THUS LEANING TWD A MODEL BLEND (OF THESE TWO) FOR THIS EVENT. WEAK SFC LOW OVER EAST CNTRL SASK WILL CONTINUE TO PUSH EAST...WITH SFC TROUGH MOVING THROUGH THE REGION OVERNIGHT. BEST UPPER LEVEL ENERGY WILL BE ACROSS SOUTHERN CANADA...AND ONLY LIGHT ACCUMULATIONS ARE EXPECTED...MAINLY OVER NORTH CENTRAL MINNESOTA. TONIGHT...SNOWFALL ACROSS THE NORTH IS EXPECTED TO COME IN TWO WAVES. WEAK VORT MAX WILL MOVE ACROSS THE NORTHERN VALLEY AND BRING A CHANCE OF SNOW TO MAINLY THE NORTHEASTERN ZONES. BOTH NAM AND RUC SHOWING THIS PRECIP TO BE RATHER LIGHT AND CLEARING EASTERN ZONES BY 03Z. EXPECT A BREAK IN PRECIP FROM ABOUT 04Z TO 08Z BEFORE SECOND BAND SETS UP...THEN EXPECT SCATTERED SNOW SHOWERS ACROSS THE NORTH. AS SFC TROUGH MOVES ACROSS THE AREA...WEAK SOUTHERN SFC LOW IS PROGGED TO GENERATE OVER CNTRL ND. 12Z NAM SHOWING A BAND OF H850-H700 LAYER FRONTOGENETIC FORCING SETTING UP ACROSS NORTHERN VALLEY AND NORTHWEST MINNESOTA. THIS BECOMES THE FOCUS FOR THE SECOND BAND OF PRECIP...WHICH HAS THE BETTER CHANCE FOR ANY ACCUMULATING SNOWFALL. PRECIP DOES MOVE OUT OF EASTERN ZONES EARLY TUE AFTN...THUS HAVE REMOVED AFTN POPS FOR TOMORROW. TUESDAY AND TUESDAY NIGHT...SOME LINGERING FLURRIES MAY CONTINUE OVER EASTERN ZONES THROUGH MID AFTERNOON...BUT HIGH PRESSURE WILL QUICKLY MOVE IN AND SHOULD MOSTLY CLEAR TO PARTLY CLOUD SKIES TOMORROW NIGHT. HIGH PRESSURE EXPECTED TO TRANSIT THE AREA OVERNIGHT...SETTING UP POTENTIAL FOR A VERY COLD WEDNESDAY MORNING. HAVE CONTINUED LEANING TOWARD THE GEM SOLUTION FOR OVERNIGHT LOWS...WHICH BRINGS OVERNIGHT LOWS OF -8 F TO -12 F ACROSS PARTS OF NORTHEASTERN ND. WEDNESDAY AND THURSDAY...DESPITE A COLD START TO THE DAY...PLENTIFUL SOLAR AND RETURN FLOW SETTING UP EARLY IN THE MORNING SHOULD ALLOW TEMPS TO REBOUND INTO THE 20S...POSSIBLY EVEN TAPPING INTO THE 30S IN FAR WESTERN ZONES. DRY SFC BOUNDARY WILL SHIFT WINDS TO THE NORTHEAST WED EVENING...AND NORTHEAST FLOW WILL KEEP DRY AIR OVER THE REGION THROUGH THE DAY THURSDAY WHILE DROPPING TEMPS BACK INTO THE TEENS FOR THE NORTHERN HALF OF THE CWA. .LONG TERM.../THURSDAY NIGHT THROUGH MONDAY/ 12Z MODELS ALL INDICATE ZONAL FLOW WITH A FEW CHANCES FOR PRECIPITATION. WILL STICK WITH THE ALLBLEND FOR POPS AS EACH MODEL IS A BIT DIFFERENT WITH TIMING AND STRENGTH OF INDIVIDUAL SHORTWAVES. THE POLAR JET RETREATS NORTH OF THE INTERNATIONAL BORDER BY MONDAY...WHICH SHOULD LEAD TO WARMER TEMPERATURES EACH DAY. && .AVIATION... MUCH OF THE PERIOD WILL BE VFR. THERE COULD BE BRIEF PERIODS OF MVFR CIGS CLOSER TO THE INTERNATIONAL BORDER ALONG WITH LIGHT SNOW SHOWERS. NOT SURE IF THESE LOWER CIGS WILL AFFECT KDVL-KTVF-KBJI...BUT WILL MONITOR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SPEICHER/TG
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1045 PM CST SUN NOV 25 2012 .DISCUSSION.../ISSUED AT 930 PM CST/ FORECAST FOR TONIGHT LOOKS IN PRETTY GOOD SHAPE. LOW LEVEL DRY AIR HAS KEPT THE LIGHT SNOW ASSOCIATED WITH THE MID LEVEL FRONT TO THE SOUTHWEST OF OUR CWA. THINK THIS WILL REMAIN THE CASE THROUGH THE NIGHT...WITH JUST SOME FLURRIES POSSIBLE ALONG AND SOUTH OF THE MISSOURI RIVER. LOW LEVEL FRONT AND PUSH OF COLDER AIR WILL MOVE ACROSS THE CWA TONIGHT FROM NORTH TO SOUTH. THINKING WE SEE ANOTHER BATCH OF STRATUS BEHIND THIS FRONT AT LEAST ACROSS THE NORTHEAST HALF OF THE CWA. THIS SHOULD KEEP TEMPERATURES FROM DROPPING AS MUCH AS THEY COULD...BUT STILL EXPECTING LOWS FROM THE LOWER TEENS NORTH TO LOWER 20S SOUTH. STRATUS MAY LINGER INTO MID MORNING...BEFORE GIVING WAY TO INCREASING SUN TOMORROW...AS MID AND HIGH CLOUDS ALSO EXIT THE REGION. /CHENARD .PREVIOUS DISCUSSION.../ISSUED AT 250 PM CST/ MAIN CHALLENGES TONIGHT LIE IN THE AMOUNT OF CLOUD COVER ACROSS THE AREA...WITH POTENTIAL IMPACTS ON OVERNIGHT LOWS...AND PRECIPITATION POTENTIAL IN OUR FAR SOUTHWEST. STRATUS WHICH RESIDED ACROSS THE AREA EARLIER IN THE DAY HAS NOW DISSIPATED OVER THE ENTIRE CWA. TEMPERATURES HAVE BEEN A BIT TRICKY WITH BREAKS IN THE CLOUDS ALLOWING FOR A RELATIVELY RAPID RISE IN TEMPERATURES IN CLEAR AREAS...THEN TEMPERED BACK OR FALLING SLIGHTLY WITH THE RETURN OF CLOUDS. CLOUDS ARE BEGINNING TO FILL BACK IN WITH TWO AREAS CONVERGING FROM THE NORTH AND SOUTH...MID CLOUDS ACROSS THE SOUTH AND LOWER CLOUDS DROPPING SOUTHWARD OUT OF NORTH DAKOTA AND NORTHERN SOUTH DAKOTA AT THIS TIME. MAY SEE A RETURN OF STRATUS...AT LEAST IN OUR EAST TONIGHT...WITH GFS/NAM/AND RAP INDICATING THE PREVIOUSLY MENTIONED STRATUS TO OUR NORTH ADVECTING SOUTHWARD ON A NORTH/NORTHWESTERLY LOW LEVEL FLOW. WHILE WE DID HAVE A COOLER DAY ACROSS THE AREA...EVEN COLDER AIR IS POISED TO DRAIN INTO THE REGION TONIGHT BEHIND A SHORTWAVE TRACKING THROUGH THE UPPER MIDWEST AND INTO THE GREAT LAKES REGION OVERNIGHT. WITH THIS...WE WILL SEE MUCH COLDER LOWS TONIGHT...MADE SOMEWHAT CHALLENGING BY WHEN/WHERE THERE IS CLOUD COVER TONIGHT. WITH WINDS REMAINING FAIRLY LIGHT OVERNIGHT...IF ANY CLEARING TAKES PLACE READINGS WILL DROP RATHER QUICKLY. AT THIS POINT...HAVE LOWS IN THE LOWER TEENS NORTH...WHERE COLD AIR ADVECTION WILL BE MOST REALIZED OVERNIGHT...TO THE LOWER 20S THROUGH OUR FAR SOUTH. AS FAR AS PRECIPITATION POTENTIAL...RADAR IMAGES HAVE SHOWN RETURNS THROUGH MUCH OF THE DAY FROM SOUTHWESTERN SOUTH DAKOTA INTO NORTHEASTERN NEBRASKA...INCLUDING OUR FAR SOUTHERN MISSOURI RIVER CORRIDOR ZONES...IN THE VICINITY OF A MIDLEVEL BOUNDARY...THOUGH WITH LOW LEVEL DRY AIR IN PLACE THE ONLY LOCALES REPORTING PRECIPITATION THUS FAR HAVE BEEN OVER SOUTHWESTERN SOUTH DAKOTA AND NORTH CENTRAL NEBRASKA. KEPT ONLY SMALL CHANCE POPS IN OUR SOUTHWESTERN AREAS AS A SHORTWAVE TRACKS OUT OF THE NORTHERN ROCKIES OVERNIGHT...THOUGH STILL APPEARS THAT THE MIDLEVEL BOUNDARY WILL BEGIN TO WEAKEN AND SAG SOUTHWARD LATE BEFORE THE BETTER UPPER LEVEL SUPPORT MOVES INTO THE REGION. THE COLDEST THERMAL PROFILES WILL BE DRAPED ACROSS OUR AREA ON MONDAY...ESPECIALLY IN OUR NORTHEAST...WITH HIGHS RANGING FROM THE LOWER 20S OVER THAT AREA TO THE LOWER 30S THROUGH THE MISSOURI RIVER CORRIDOR. ALL MODEL RH TIME SECTIONS SHOWING CLOUDS EVENTUALLY CLEARING OUT BY MONDAY AFTERNOON...SO SHOULD SEE MOSTLY SUNNY SKIES BY THAT TIME OVER AT LEAST THE NORTHERN TWO THIRDS OF OUR CWA. /JM SPLIT JET ACROSS THE US IS EXPECTED TO FOCUS MAINLY ON THE NORTHERN BRANCH THROUGHOUT THE WEEK AS THE SOUTHERN BRANCH WEAKENS. THROUGHOUT THE WEEK...THE NORTHERN BRANCH OF THE JET IS EXPECTED TO BUCKLE NORTH AS NORTHWEST FLOW TRANSITIONS TO ZONAL FLOW IN THE MID LEVELS OF THE ATMOSPHERE. THIS WOULD TYPICALLY RESULT IN A WARMING TREND...HOWEVER...CLOUD COVER WILL LIKELY HAVE THE MAIN EFFECT ON TEMPERATURES. A WEAK COLD FRONT WILL MOVE THROUGH THE AREA ON TUESDAY AFTERNOON. BOUNDARY IS MAINLY FOCUSED IN THE LOWER LEVELS WITH LITTLE IN THE WAY OF COLD AIR BEHIND THE FRONT. STILL APPEARS AS THOUGH SOME STRATUS MAY WORK INTO THE FORECAST AREA FROM THE NORTH TUESDAY NIGHT LIMITING RADIATIONAL IMPACT. WITH WEAK FLOW ACROSS THE AREA ON WEDNESDAY...WILL BE A STRUGGLE FOR AREAS IN THE EAST TO WARM IF STATUS IS ABLE TO PENETRATE INTO THE FORECAST AREA. FOR NOW...HAVE COOLED FORECAST HIGHS IN SOUTHWEST MINNESOTA...CLOSE TO 925 HPA ISOTHERMAL...THOUGH MAY HAVE TO EXPAND THE COOLING AS CONFIDENCE IN THE STRATUS INCREASES. WEDNESDAY NIGHT A WEAK BOUNDARY APPROACHES FROM THE WEST WITH NO UPPER LEVEL SUPPORT. MODELS HINT THAT THE BOUNDARY MAY STALL ACROSS WESTERN PORTIONS OF THE FORECAST AREA...LEAVING THE EAST IN MILD SOUTHERLY FLOW. THE EAST MAY STILL BE DEALING WITH STRATUS CONCERNS...SO HAVE SQUASHED DIURNAL RANGE A BIT THURSDAY INTO FRIDAY. OVERALL...HAVE A GRADUAL WARMING TREND AS 925 HPA TEMPS WARM FROM 5 TOWARDS 10 DEGREES C. MODELS SHOW ANOTHER COLD FRONT MOVING THROUGH THE AREA LATE ON SATURDAY...THOUGH THE STRENGTH OF THE FRONT IS UNDER DEBATE. RIGHT NOW...THE GFS IS MUCH WEAKER WITH THE FRONT THAN THE ECMWF. WHILE THE MID LEVEL PATTERN IS MORE ACTIVE...MOISTURE STILL APPEARS TO BE QUITE LIMITED SO KEPT DRY FORECAST THROUGH NEXT WEEKEND. STILL APPEARS AS THOUGH A MORE SIZABLE SYSTEM WILL WORK THROUGH THE NORTHERN PLAINS EARLY THE FOLLOWING WEEK...THOUGH MODELS HAVE BEEN TRENDING NORTH OF THE FORECAST AREA WITH THE MIDLEVEL WAVE. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ OCCASIONAL MVFR CEILINGS MAINLY NORTH OF A HON-FSD-SPW LINE THROUGH 12Z MONDAY. OTHERWISE VFR CONDITIONS THROUGH 06Z TUESDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
547 PM CST TUE NOV 27 2012 .SHORT TERM...THROUGH FRIDAY 200 PM CST TUE NOV 27 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THIS EVENING AS WELL AS THURSDAY NIGHT INTO FRIDAY. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING FROM THE BRITISH COLUMBIA COAST SOUTHWARD THROUGH THE WESTERN U.S....WHILE TROUGHING WAS PRESENT FROM SOUTHEAST CANADA INTO THE GREAT LAKES. IN THE NORTHWEST FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE TROUGH WAS NOTED OVER NORTHERN MINNESOTA. ISENTROPIC LIFT DEPICTED ON THE 285-295K SURFACES AHEAD OF THE SHORTWAVE HAS RESULTED IN SCATTERED-BROKEN ALTOSTRATUS ACROSS THE FORECAST AREA. FARTHER NORTH...SNOW HAS BEEN FALLING ACROSS NORTHERN MINNESOTA INTO NORTHERN WI WHERE THE DPVA AND ISENTROPIC LIFT FORCING IS STRONGEST...ALONG WITH BETTER LOW LEVEL SATURATION PER 12Z INL SOUNDING. A COLD FRONT REPRESENTING THE SHORTWAVE AT THE SURFACE EXTENDED FROM NORTHEAST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA. SOUTHWEST WINDS AHEAD OF THE FRONT HAS HELPED PULL WARMER AIR INTO THE REGION...NOTED BY 925MB TEMPS THAT HAVE CLIMBED AT MPX FROM -11C AT 00Z TO -4C AT 12Z PER SOUNDINGS. READINGS HAVE CLIMBED INTO THE LOW TO MID 30S IN MOST LOCATIONS. BEHIND THE FRONT ACROSS SOUTH DAKOTA...READINGS ARE NOT THAT MUCH COOLER. HOWEVER...ACROSS SOUTHERN MANITOBA WHERE HIGH PRESSURE SITS...READINGS ARE IN THE LOWER TEENS. 925MB TEMPS IN THIS AREA ARE -14 TO -18C PER RAP ANALYSIS. TONIGHT AND WEDNESDAY...THE UPPER LEVEL PATTERN IS FORECAST TO DEAMPLIFY SOME ACROSS THE CONUS...IN RESPONSE TO A PORTION OF EAST PACIFIC TROUGHING MOVING INTO THE WESTERN U.S.. BY 00Z THURSDAY... 500MB HEIGHTS WILL HAVE RISEN NEARLY 120 METERS OVER THE FORECAST AREA. SUBSIDENCE ASSOCIATED WITH THESE HEIGHT RISES SHOULD KEEP THE MAJORITY OF THE NEXT 24 HOURS QUIET. THE ONLY CONCERN IS WITH THE SHORTWAVE OVER NORTHERN MINNESOTA DROPPING SOUTHEAST THROUGH NORTHERN WISCONSIN THIS EVENING. THE 280-285K ISENTROPIC LIFT HELPING TO PRODUCE THE SNOW ACROSS NORTHERN MINNESOTA WILL ACCOMPANY THE SHORTWAVE SOUTHEASTWARD. RIGHT NOW IT APPEARS THE BULK OF THE SNOW SHOULD STAY NORTH OF THE FORECAST AREA...PER MODEL CONSENSUS AND SHORTWAVE TRACK...BUT AM CONCERNED AT LEAST SOME FLURRIES COULD OCCUR OVER TAYLOR/CLARK. HAVE ADDED THE FLURRIES INTO THE FORECAST. EVENING SHIFT WILL NEED TO WATCH THE SNOW PROGRESSION. OTHERWISE... THE COLD FRONT LOOKS TO MOVE THROUGH MUCH OF THE FORECAST AREA BY 09Z. 925MB TEMP PROGS SUGGEST A PORTION OF THAT COLDER AIR IN SOUTHERN MANITOBA WILL MAKE IT SOUTH INTO THE FORECAST AREA...WITH TEMPS AT 12Z WEDNESDAY RANGING FROM -2C OVER NORTHEAST IOWA TO -8 TO -10C IN TAYLOR COUNTY. AS SUCH...THE COLDEST READINGS TONIGHT ARE IN TAYLOR COUNTY. THE WINDS AND SOME STRATUS CLOUDS BEHIND THE FRONT SHOULD MITIGATE THE TEMPERATURE FALL SOMEWHAT...THOUGH. THE 925MB TEMPS HOLD FAIRLY STEADY THROUGH ABOUT 18Z...DUE TO HIGH PRESSURE SLIDING ACROSS... THEN BEGIN TO CLIMB. MIXING TO THE 925MB TEMPS RESULTS IN HIGHS IN THE UPPER 20S TO NEAR 40...COLDEST ACROSS TAYLOR AND CLARK COUNTIES. THIS MIXING SHOULD BE DOABLE DESPITE SOME INCREASE IN HIGH CLOUDS DEPICTED IN THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY...SOME MORE 500MB HEIGHT RISES ARE FORECAST OVER THE AREA...IN RESPONSE TO THE WESTERN U.S. RIDGE FLATTENING OUT AND BEING PUSHED EASTWARD BY THE PORTION OF THE EAST PACIFIC TROUGH HEADING INTO THE DAKOTAS BY 00Z FRIDAY. SUBSIDENCE AGAIN ASSOCIATED WITH THESE HEIGHT RISES SHOULD BE ENOUGH TO KEEP THE AREA DRY. THIS SUBSIDENCE DOES LOOK TO CLEAR THE CIRRUS OUT WEDNESDAY NIGHT. HOWEVER...AN INCREASE IN CIRRUS IS EXPECTED ACROSS MUCH OF THE AREA ON THURSDAY AS THAT SHORTWAVE TROUGH COMES INTO THE DAKOTAS. IN ADDITION...A MASS OF LOW CLOUDS IS PROGGED TO COME INTO NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY AFTERNOON. THESE ARE IN THE WAKE OF A COLD FRONTAL PASSAGE...FORECAST TO DROP SOUTH THROUGH THE AREA MOSTLY DURING THE MORNING. 925MB TEMPS CLIMB NICELY WEDNESDAY NIGHT AHEAD OF THAT FRONT DROPPING SOUTH...TOPPING OUT BETWEEN 2C AND -2C BY 12Z. THIS WARM ADVECTION COMBINED WITH A SOUTHERLY BREEZE SHOULD HELP KEEP TEMPERATURES UP. A BLEND OF GUIDANCE SEEMS REASONABLE FOR LOWS SUGGESTING MAINLY IN THE 20S. FOR THURSDAY...925MB TEMPS FALL TO 0 TO -4C AT 18Z THURSDAY...THOUGH THE WARMER NIGHT AND SOME FILTERED SUNSHINE WILL ALLOW TEMPERATURES TO BE ABOUT 5 DEGREES WARMER THAN WEDNESDAY. THURSDAY NIGHT AND FRIDAY...THE SHORTWAVE TROUGH ACROSS THE DAKOTAS MODELS FORECAST TO COME ACROSS THE AREA FRIDAY MORNING. MODELS VARY ON STRENGTH OF THE TROUGH...WITH THE 27.12Z GFS STRONGEST AND 27.12Z NAM WEAKEST. HOWEVER...THE STRENGTH OF THE SHORTWAVE APPEARS TO HAVE LITTLE SENSIBLE IMPACT ON THE WEATHER AS THE MID-LEVELS OF THE ATMOSPHERE ARE SUGGESTED TO BE QUITE DRY. IN FACT...MUCH OF THE ACTION LOOKS TO OCCUR BELOW 850MB. THE POST-FRONTAL LOW CLOUD MASS DROPPING SOUTH THURSDAY AFTERNOON MODELS ARE IN GOOD AGREEMENT IN HAVING IT ENCOMPASS LOCATIONS FROM I-90 NORTH BY 06Z FRIDAY. THE LOW CLOUD DECK MAY EVEN DRIFT FARTHER SOUTH BETWEEN 06-12Z TO ENCOMPASS MOST OF THE AREA. THE REASON THIS IS SO IMPORTANT IS THAT ISENTROPIC LIFT PLOTS SHOW WEAK LIFT ON THE 280-285K SURFACES THURSDAY NIGHT INTO FRIDAY MORNING. THE LIFT IN THE LOW CLOUD DECK COULD RESULT IN SOME LIGHT FREEZING DRIZZLE DEVELOPING. SINCE THIS HAS BEEN A CONSISTENT SIGNAL...HAVE INCLUDED THE MENTION OF IT IN THE FORECAST. GIVEN THE IMPACTS FROM JUST A TINY BIT OF FREEZING DRIZZLE...MAY NEED AN ADVISORY AT SOME POINT. ALSO ADDED A FOG MENTION AREA WIDE FOR 06-18Z FRIDAY GIVEN THE VERY LOW CEILINGS PROGGED. CLOUDS LOOK TOUGH TO CLEAR TOO FRIDAY AFTERNOON AS A GENERAL EAST-SOUTHEAST LOW LEVEL FLOW PERSISTS. THUS...ANTICIPATING MUCH OF THIS 24 HOUR PERIOD TO BE CLOUDY. THE CLOUDS WILL LIMIT THE DIURNAL FALL AND RISE...AND IT IS WORTH NOTING THAT 925MB TEMPS CHANGE VERY LITTLE THROUGH FRIDAY SUGGESTING LITTLE IN THE WAY OF ADVECTION. THUS... TEMPERATURES SHOULD NOT CHANGE A WHOLE LOT. ONLY HAVE ABOUT A 10 DEGREE CHANGE FROM NIGHT AND DAY IN THE FORECAST. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY 200 PM CST TUE NOV 27 2012 VERY GOOD MODEL AGREEMENT EXISTS AND REMAINS AMONGST THE 27.12Z ECMWF/GFS/UKMET/CANADIAN AND GFS ENSEMBLES THROUGH MUCH OF THE LONG TERM FORECAST...BOTH AT THE SURFACE AND ALOFT. THE UPPER LEVEL FLOW THROUGH THE SHORT TERM PERIOD THAT IS TRANSITIONING FROM NORTHWEST TO ZONAL BECOMES SOUTHWESTERLY FOR THE WEEKEND. THE FLOW THEN AMPLIFIES AS A PROGRESSIVE DEEP TROUGH MARCHES ACROSS THE WEST AND CENTRAL U.S. EARLY NEXT WEEK. MAIN PRECIPITATION TIMES OF NOTE ARE ON SATURDAY INTO SATURDAY EVENING...AS WELL AS MONDAY INTO MONDAY NIGHT. THE FIRST IS ASSOCIATED WITH A SHORTWAVE TROUGH COMING THROUGH THE SOUTHWESTERLY FLOW. A SURGE OF GULF OF MEXICO MOISTURE ACCOMPANIES THE TROUGH AS IT MOVES INTO THE AREA...ENOUGH TO LIKELY PRODUCE A LOW LEVEL STRATUS DECK AS WELL AS SOME LIGHT PRECIPITATION. RIGHT NOW MAYBE WE GET UP TO A TENTH OF AN INCH AT MOST. THE MONDAY INTO MONDAY NIGHT PERIOD IS MORE INTERESTING HAVING A DYNAMIC DEEP TROUGH COMING ACROSS. 850MB WINDS INCREASE TO 40-50 KT HELPING TO BRING 850MB DEWPOINTS UP TO 8C OR SO. ONE ISSUE IS THAT THE SATURATION AGAIN IS ALL IN THE LOW LEVELS...AND THE ATMOSPHERE IS CAPPED...THUS ANOTHER LIGHT RAIN/DRIZZLE EVENT WOULD OCCUR. OVERALL...THOUGH...CONFIDENCE IN EITHER EVENT PRODUCING WIDESPREAD QPF IS FAIRLY LOW AT THIS POINT SINCE THE DYNAMICAL FORCING IS ALL NORTH OF THE AREA. THUS...PRECIPITATION CHANCES ARE IN THE 20-40 RANGE. TEMPERATURES ARE MORE INTERESTING HERE IN THE LONG TERM PERIOD. 925MB TEMPS ARE FORECAST BETWEEN 3-7C ON SATURDAY...AS MUCH AS 6-10C ON SUNDAY PER 27.00Z/12Z ECMWF AND 10-14C BY LATE IN THE DAY MONDAY. THE INCOMING STRATUS DECK ON BOTH SATURDAY AND MONDAY WILL LIKELY HOLD BACK THE POTENTIAL FOR MIXING TO 925MB. HOWEVER...ADVECTION ALONE SHOULD BE ABLE TO PUSH READINGS INTO THE MID 40S TO LOW 50S ON SATURDAY AND INTO THE 50S EVERYWHERE ON MONDAY PER MODEL CONSENSUS. SHOULD ANY UNEXPECTED SUNSHINE OCCUR...HIGHS COULD EASILY BE HIGHER. MONDAYS FORECAST HIGHS ARE ONLY A FEW DEGREES BELOW RECORDS...59 AT ROCHESTER AND 61 AT LA CROSSE. SUNDAY HAS THE BEST OPPORTUNITY FOR SUNSHINE...AND IF THE ECMWF IS CORRECT...WE COULD EASILY CLIMB INTO THE 50S AND PERHAPS REACH 60 IN SOUTHERN AREAS. HAVE BUMPED UP HIGHS ABOVE THE CONSENSUS TO RANGE FROM THE MID 40S TO MID 50S. IT APPEARS RECORDS ON SUNDAY SHOULD BE SAFE WITH ROCHESTER AT 62 AND LA CROSSE AT 64. FOR TUESDAY...DECENT COOLING COMES IN THANKS TO THE UPPER TROUGH SLIDING INTO THE AREA. FOLLOWED THE CONSENSUS HIGHS IN THE 40S FOR NOW. && .AVIATION...TONIGHT AND WEDNESDAY 547 PM CST TUE NOV 27 2012 A COLD FRONT IS APPROACHING THE REGION FROM THE WEST WITH LOW TO MID LEVEL CLOUD COVER BROKEN TO OVERCAST BETWEEN 4-8KFT THROUGH THE UPPER MISSISSIPPI RIVER VALLEY REGION. A FEW FLURRIES HAVE BEEN OBSERVED ACROSS NORTH CENTRAL WISCONSIN...BUT WILL STAY NORTH OF THE TAF SITES. AFTER A CLEAR PERIOD WHEN THE COLD FRONT COMES THROUGH...THE QUESTION WILL BE WHETHER OR NOT A 1-2KFT STRATUS DECK MAKES IT DOWN INTO THE REGION OVERNIGHT. CURRENTLY...THE SOUTHERN EXTENT OF IT WAS ALONG THE NORTH/SOUTH DAKOTA BORDER RUNNING EAST ACROSS CENTRAL MINNESOTA...BUT HAS NOT MADE MUCH PROGRESS SOUTH OVER THE PAST HOUR OR SO. WILL CONTINUE TO MONITOR THIS CLOUD DECK THIS EVENING AND MAY HAVE TO AMEND THE CURRENT TAFS FROM SCT TO BKN/OVC IF IT APPEARS THAT THIS DECK WILL MAKE IT DOWN. CONFIDENCE WAS NOT HIGH ENOUGH TO MAKE THAT CHANGE RIGHT NOW HOWEVER WITH GUIDANCE SHOWING HINTS OF IT MAKING IT DOWN...BUT SCATTERING IT OUT AS DRIER AIR MOVES IN. WINDS WILL GO TO THE NORTHWEST AFTER THE FRONT PASSES AND THEN SHIFT TO THE WEST OVERNIGHT BEFORE GOING TO THE SOUTH TOMORROW AS A RIDGE AXIS MOVES THROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... 200 PM CST TUE NOV 27 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
539 PM CST TUE NOV 27 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE DROPPING SOUTHEAST OVER WESTERN WISCONSIN EARLY THIS AFTERNOON...AND IS KICKING OFF SNOW SHOWERS OVER THE NW CORNER OF THE STATE. A FEW SNOW SHOWERS LOOK RATHER BEEFY ON RADAR...AND AN OBSERVATION AT HAYWARD DROPPED VSBYS DOWN TO A QUARTER MILE BRIEFLY. WILL BE ON THE LOOK OUT FOR A HISA EVENT THIS AFTERNOON. COLD FRONT IS TRAILING THE LEAD SHORTWAVE...AND IS POSITIONED FROM THE ARROWHEAD OF MINNESOTA TO NORTHERN SOUTH DAKOTA. A WIDESPREAD LOW STRATUS DECK EXISTS IMMEDIATELY BEHIND THIS FRONT...AND A FEW FLURRIES HAVE BEEN NOTED ON THE OBS THERE TOO. AS SHORTWAVE ACTIVITY AND THE COLD FRONT CROSS THE REGION TONIGHT...CLOUDS AND PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS. TONIGHT...WEAK SHORTWAVE ACTIVITY WILL SWING ACROSS THE REGION TONIGHT AND PUSH A COLD FRONT ACROSS THE AREA. THOUGH MOISTURE IS GENERALLY LACKING...MOISTURE IS GREATER TO THE NORTH. RADARS SUGGEST N-C WISCONSIN WILL SEE LIKELY SNOW SHOWERS THIS EVENING SO WILL RAISE POPS A BIT. NOT SURE HOW FAR SOUTH TO BRING A MENTION OF FLURRIES...BUT NORTH OF ROUTE 29 SEEMS LIKE A LOGICAL DIVIDER BASED ON RADAR TRENDS. BEHIND THE FRONT...A LOW STRATUS DECK HAS BEEN ADVANCING SOUTHEAST. MODELS SCOUR OUT THE LOW LEVEL MOISTURE TONIGHT AND SUGGEST THIS STRATUS DECK MAY ONLY REACH N-C WISCONSIN. GIVEN THE SOLID LOOK TO THE STRATUS AND THE COLD ADVECTION TO TAKE PLACE...THINK THIS IS TOO OPTIMISTIC AND WILL BRING THE STRATUS DECK INTO CENTRAL WISCONSIN AS WELL. BY THE TIME IT GETS THERE LATE TONIGHT...ENOUGH DRY AIR AND DOWNSLOPING SHOULD KEEP THE STRATUS FROM REACHING NE AND E-C WISCONSIN. NORTHWEST WINDS WILL KEEP SNOW SHOWERS AND FLURRIES GOING OVER VILAS COUNTY THROUGH THE NIGHT HOWEVER. A STRONGER PRESSURE GRADIENT SHOULD KEEP THE BL MIXED ENOUGH TO GO WITH WARMER TEMPS COMPARED TO LAST NIGHT. WILL GO WITH LOW TEENS NORTH TO NEAR 20 SE. WEDNESDAY...PRETTY QUIET AS HIGH PRESSURE RIDGE AXIS WORKS ACROSS THE STATE. BACKING LOW LEVEL WINDS WILL FORCE LAKE CLOUDS TO LIFT OFF TO THE NORTHEAST AND AWAY FROM N-C WISCONSIN DURING THE MORNING. IF LOW STRATUS DOES STICK AROUND INTO WEDNESDAY MORNING...THINK THE INCOMING RIDGE AXIS WILL CAUSE ANY CLOUDS TO BREAK UP EARLY IN THE PERIOD. MOST OF THE AREA SHOULD SEE MOSTLY SUNNY CONDITIONS FOR MUCH OF THE DAY. HIGHS RANGING FROM THE MID 20S NORTH TO LOWER 30S SOUTH. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. WINTER IS SLOW TO ARRIVE THIS YEAR AND THE MEDIUM RANGE MODELS SUGGEST THAT THE MILD WEATHER PATTERN WILL CONTINUE. DRY NORTHWEST FLOW IS EXPECTED THROUGH THURSDAY WITH TEMPERATURES RISING ABOVE NORMAL FOR THIS TIME OF THE YEAR. UPPER FLOW IS FORECAST TO BECOME ZONAL FRIDAY THROUGH SUNDAY WITH SOME OVERRUNNING LIGHT SNOW...DRIZZLE OR FREEZING DRIZZLE THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH THE FLOW. MOISTURE IS SHALLOW AND NOT VERY ABUNDANT SO DO NOT EXPECT MUCH. A MORE SIGNIFICANT SHORTWAVE IS EXPECTED SATURDAY AFTERNOON OR EVENING WHICH SHOULD HAVE A BIT MORE MOISTURE AS WELL. TEMPERATURES WILL BE WELL ABOVE FREEZING SO WHATEVER FALLS SHOULD BE RAIN. UPPER RIDGE REALLY BUILDS MONDAY AND SOUTHERLY LOW LEVEL FLOW INCREASES TOO. 925MB TEMPERATURES FORECAST TO RISE TO +10C MONDAY AFTERNOON AND EVENING WHICH COULD HELP DRIVE TEMPERATURES INTO THE 50S IF THERE IS ANY SUNSHINE AT ALL. A COLD FRONT WILL MOVE THROUGH MONDAY NIGHT AND BRING SLIGHTLY COOLER AIR FOR TUESDAY. && .AVIATION...SNOW SHOWERS SHOULD TAPER OFF ACROSS FAR NORTHERN WI EARLY THIS EVG...ALTHOUGH SCT LAKE EFFECT SNOW SHOWERS MAY LINGER PAST MIDNIGHT OVER VILAS COUNTY. ELSEWHERE...SCT FLURRIES WILL ACCOMPANY A COLD FRONT AS IT CROSSES THE AREA TONIGHT. SOME MVFR CIGS ARE EXPECTED OVER NORTH CENTRAL AND CENTRAL WI NEAR AND BEHIND THE COLD FRONT...ALTHOUGH CLEARING IS EXPECTED IN MOST AREAS TOWARD DAYBREAK. HIGH PRESSURE WILL BRING VFR CONDITIONS ON WEDNESDAY. KIECKBUSCH && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
224 PM CST MON NOV 26 2012 .SHORT TERM...TONIGHT AND TUESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A 1033MB HIGH PRESSURE SYSTEM MOVING SOUTHEAST OVER THE NORTH-CENTRAL GREAT PLAINS. NORTHWEST FLOW ALONG THE THE FRONT SIDE OF THE HIGH CONTINUES TO PRODUCE LAKE CLOUDS AND FLURRIES OVER N-C WISCONSIN EARLY THIS AFTERNOON...BUT THESE CLOUDS SHOULD START TO ERODE LATER IN THE DAY AS THE SURFACE HIGH BRINGS DRIER AIR INTO THE STATE. LOW LEVEL WARM ADVECTION IS OCCURRING UPSTREAM OVER NORTH DAKOTA AND SOUTHERN CANADA WHERE THERE ARE A FEW REPORTS OF SNOW SHOWERS AND FLURRIES. AS THIS WARM ADVECTION ARRIVES LATE TONIGHT INTO TUESDAY...CLOUDS AND SNOW CHANCES ARE THE MAIN FORECAST CONCERNS. TONIGHT...NORTHWEST FLOW TO PREVAIL TONIGHT ACROSS THE WESTERN GREAT LAKES. WEAK SHORTWAVE EMBEDDED WITHIN THE FLOW WILL PASS OVER NORTHERN ILLINOIS THIS EVENING WHILE HIGH PRESSURE PASSES ACROSS THE STATE OF WISCONSIN. AS LOW LEVEL WINDS BACK AROUND TO THE WEST...THEY WILL PUSH DRIER AIR ACROSS NORTHERN WISCONSIN AND LAKE EFFECT CLOUDS SHOULD EXIT TO THE NORTHEAST. SO SHOULD HAVE A MOSTLY CLEAR EVENING AND WINDS HAVE A CHANCE TO DECOUPLE...WHICH WOULD HELP TEMPS PLUMMET OVER N-C WISCONSIN ONCE SKIES CLEAR. TEMPS UPSTREAM IN MINNESOTA FELL NEAR ZERO...AND THINK POTENTIAL IS THERE FOR THAT TO OCCUR. WILL TREND TEMPS LOWER. AFTER MIDNIGHT...A WEAK SHORTWAVE WILL DROP SOUTHEAST ACROSS SOUTHERN CANADA AND WILL SEND SCT-BKN LOW AND MID CLOUDS ACROSS THE NORTHWEST PART OF THE STATE. FLURRIES NOTED OVER SOUTH-CENTRAL CANADA SHOULD STAY TO OUR NORTH. ONCE THE CLOUDS ARRIVE...TEMPS MAY REBOUND A BIT. LOWS IN THE MID SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR LAKE MICHIGAN. TUESDAY...THE SHORTWAVE ENERGY WILL DROP INTO THE WESTERN GREAT LAKES ON TUESDAY AND WILL PUSH A COLD FRONT INTO NORTHWEST WISCONSIN DURING THE AFTERNOON. LOW LEVEL WARM ADVECTION CLOUDS WILL LIKELY LIFT OUT TO THE NORTHEAST IN THE MORNING. PLENTY OF MID AND HIGH CLOUDS WILL BE AROUND TO MAKE THIS A PARTLY SUNNY TO MOSTLY CLOUDY DAY. AHEAD OF THE FRONT...LOW CLOUDS WILL BE ON THE INCREASE OVER N-C AND CENTRAL WISCONSIN IN THE AFTERNOON. PREVIOUS SHIFT ADDED A CHANCE OF SNOW SHOWERS...AND THIS LOOKS GOOD. HIGHS IN THE MIDDLE 20S NORTH TO THE LOWER 30S SOUTH. .LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY. LOOKS LIKE A FAIRLY QUITE PERIOD OF WEATHER WITH LITTLE OR NO SNOW AND TEMPERATURES WARMING ABOVE NORMAL. NORTHWEST UPPER FLOW WILL KEEP TEMPERATURES NEAR NORMAL WEDNESDAY BUT THEN UPPER FLOW WILL BACK AND BECOME ZONAL BY THE END OF THE WEEK. A COUPLE OF WEAK SHORTWAVES ARE EXPECTED TO MOVE THROUGH THE UPPER FLOW FRIDAY AND SATURDAY SETTING UP SOME LIGHT OVERRUNNING PRECIPITATION. IT MAY BE COLD ENOUGH FOR SOME SNOW FRIDAY BUT AFTER THAT IT LOOKS TOO WARM FOR ANYTHING BUT LIGHT RAIN. SOUTHERLY SURFACE FLOW WILL BRING UP WARM AND MOIST AIR OVER THE COLD GROUND AND MAY PRODUCE DENSE FOG AT SOME POINT LATE IN THE WEEK. && .AVIATION...MVFR CIGS TO IMPROVE TO VFR THIS AFTERNOON OVER NORTHERN WISCONSIN AS HIGH PRESSURE BUILDS INTO THE REGION. MOSTLY CLEAR SKIES THIS EVENING WILL GIVE WAY TO INCREASING CLOUDS AFTER MIDNIGHT. CIGS UPSTREAM OVER NORTH DAKOTA ARE MAINLY VFR THOUGH OBS ARE SHOWING LIGHT SNOW AND FLURRIES. WILL LET LATER SHIFTS ADD -SN TO THE FORECAST AS NEEDED. A BREAK IN THE CLOUDS IS POSSIBLE TUESDAY MORNING BEFORE CLOUDS INCREASE AGAIN DURING THE AFTERNOON. MEANWHILE...AN INCREASING PRESSURE GRADIENT WILL LEAD TO THE POSSIBILITY OF WIND SHEAR DEVELOPING TOMORROW MORNING OVER NORTHERN WISCONSIN. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/RDM
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
314 AM EST Wed Nov 28 2012 .NEAR TERM [Today and Tonight]... The immediate forecast challenge is related to fog. As expected, the lowest visibilities per observations have been over the east half of the area (SW GA and FL Big Bend). Although the southern half of the Dense Fog Advisory area has not yet seen many 1/4SM visibilities observed, we plan to leave the advisory in tact for now. The latest ensemble probabilities continue to favor a high likelihood for visibility at or below 1SM over the advisory area. A frontal inversion should keep the mixed layer relatively shallow today, which will keep temperatures cooler than the +10 to +11C 850mb temperatures would suggest. In shallow CAA regimes just after a cold front passage, the morning temperatures tend to be slower to increase than the typical diurnal curve. The temperature curve was nudged down in the morning to account for this. However, with breaks of sun likely to develop by afternoon we are still expecting highs to get into the 60s just about everywhere. For tonight, some MOS guidance is still indicating lows close to freezing in our SE Alabama zones. However, it would take a very strong inversion to produce lows of those values given the temperature profile in the 925-850mb layer. That is not expected to be the case, and so despite clear skies and lighter winds the lows should mainly stay in the 37-42 degree range. These types of lows would also prevent frost in most spots. && .SHORT TERM [Thursday Through Friday]... A lingering low-level ridge of high pressure along the Atlantic seaboard will keep east to northeast flow in place across much of the east coast. This pattern should prevent rapid modification of the cooler air mass that will be in place. However, highs should increase a couple degrees each day at the end of the work week with mostly sunny skies and a deeper mixed layer each afternoon. && .LONG TERM [Friday Night through next Wednesday]... Guidance is in good agreement that the flow across the CONUS will continue to be fast and primarily zonal through early next week. The primary jet and any associated disturbances are forecast to remain well north of the forecast area through next Tuesday, before digging southward by midweek and driving a cold front towards the Gulf Coast. Before this trough digs southward, expect an upper ridge to develop over the gulf and nose northeast across the area. The impact of this upper pattern will be for warmer than normal temperatures into early next week, with minimal rain chances. Expect highs in the mid 70s with lows generally in the lower 50s. Rain chances will be introduced for late Tuesday into Wednesday ahead of the approaching cold front. && .AVIATION [through 06z Thursday]... Low CIGS & fog currently dominate the region with IFR conditions ongoing at all terminals. Expect conditions to occasionally reach airport minimums until after sunrise. Thereafter, the overcast should gradually burn off, with VFR conditions anticipated by afternoon and continuing into Wednesday night. && .MARINE... With the 4am CWF issuance, we plan to maintain the SCEC headline across all but the far eastern nearshore zones (Apalachee Bay and along Taylor and Dixie Counties) through mid-morning. The latest buoy and tower observations continue to indicate winds around 15-16 knots over the bulk of the coastal waters, with a few gusts to around 20 knots. A 0315z ASCAT pass also showed a sizable swath of 15-20 knot winds, which matched well with RAP and local WRF (which were used as the basis for the updated wind forecast in the first 12 hours). Winds quickly veer to the east by tonight as high pressure settles into the Southeast, setting up the typical surges of easterly winds at night over the next few days. && .FIRE WEATHER... A slightly drier airmass will filter into the region today in the wake of a cold front. However, humidity values are not forecast to reach critical levels, and ERC values should remain below thresholds following Tuesdays rainfall. By Thursday into the weekend, easterly flow is forecast to bring in enough Atlantic moisture to keep RH values above critical levels. No Red Flag conditions are expected through the end of the work week. && .HYDROLOGY... Rainfall totals over the past 24 hours ranged from nil or trace amounts near the Suwannee River in the eastern Florida Big Bend, to around an inch in southeast Alabama. These rain amounts are not expected to cause any notable changes in the area rivers. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 67 39 70 45 74 / 0 0 0 10 10 Panama City 66 45 68 51 72 / 0 0 0 10 10 Dothan 64 38 67 45 71 / 0 0 0 10 10 Albany 63 37 68 43 72 / 0 0 0 10 10 Valdosta 66 41 70 47 73 / 0 0 0 10 10 Cross City 71 43 74 47 76 / 0 0 0 10 10 Apalachicola 66 47 67 53 71 / 0 0 0 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY until 8 AM EST this morning for Gadsden- Inland Franklin-Inland Jefferson-Inland Taylor-Inland Wakulla-Lafayette-Leon-Liberty-Madison. GA...DENSE FOG ADVISORY until 6 AM EST early this morning for Baker- Ben Hill-Berrien-Calhoun-Colquitt-Cook-Decatur-Dougherty- Early-Irwin-Lee-Miller-Mitchell-Seminole-Tift-Turner- Worth. DENSE FOG ADVISORY until 8 AM EST this morning for Brooks- Grady-Lanier-Lowndes-Thomas. AL...None. GM...None. && $$ NEAR AND SHORT TERM...Lamers LONG TERM...Camp AVIATION...Camp MARINE...Lamers FIRE WEATHER...Camp HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS JACKSON KY
233 AM EST WED NOV 28 2012 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 233 AM EST WED NOV 28 2012 EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY. THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY SKIES. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 203 AM EST WED NOV 28 2012 SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS. THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND. UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN ON TUE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1230 AM EST WED NOV 28 2012 LOW CLOUDS HAVE SHOWN LITTLE SIGNS OF ERODING OVERNIGHT AND WILL LIKELY PERSIST THROUGH AT LEAST DAYBREAK FOR THE TAF SITES. THIS CLOUD COVER HAS ALREADY PROVED TO BE STUBBORN AND DESPITE THE LACK OF MODEL SUPPORT...THE CLOUD COVER COULD PERSIST THROUGH THE MORNING BEFORE FINALLY STARTING TO ERODE LATER THIS AFTERNOON. HOWEVER...WITH NORTHWEST FLOW IN PLACE AND NO REAL SURGE OF DRIER AIR...WE MAY CONTEND WITH THE CLOUD COVER FOR A GOOD CHUNK OF THE DAY. NOT GOING TO CARRY CLOUDS THIS LONG THOUGH AS CONFIDENCE REMAINS VERY LOW. REGARDLESS...GOING TO PLAN FOR MORE LOW CLOUDS UNTIL WE SEE SOME EVIDENCE THEY ARE GOING TO GO AWAY WHICH MAY NOT BE UNTIL THIS TONIGHT WITH THE RIDGE AXIS FINALLY PUSHES TOWARDS THE AREA FROM THE WEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM....DUSTY AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 AM EST WED NOV 28 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST HRRR SHOWS THE STRATOCU DECK CONTINUING TO ERODE TO THE EAST. WOULD EXPECT PARTLY TO MOSTLY SUNNY SKIES THIS MORNING ACROSS MUCH OF THE REGION. HOWEVER...WITH COLD AIR ALOFT AND 85H WINDS BACKING TO THE NW...SCT-BKN CU SHOULD REDEVELOP THIS AFTERNOON. LATEST RAP FORECAST SOUNDINGS REINFORCE THE IDEA OF CLOUD DEVELOPMENT WITH DAYTIME HEATING. TEMPS WILL REMAIN BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT FLURRIES ACROSS THE NW. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... CONTINUED SUBSIDENCE FROM HIGH PRESSURE WILL ALLOW CEILINGS TO BREAK BY MID-MORNING WITH VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME NEAR CALM OVERNIGHT. WINDS WILL BECOME MORE WESTERLY ON WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING. .OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1232 AM EST WED NOV 28 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /THROUGH TODAY/... STRATOCU CONTINUES TO FILL INTO THE WEST...LIKELY AS A RESULT OF A WEAK SHORTWAVE TROUGH MOVING THROUGH. WOULD EXPECT THE WESTERN EDGE OF THE CLOUD DECK TO BEGIN TO DECAY AS DRIER AIR FURTHER WEST SLOWLY MOVES EASTWARD. LATEST RAP SOUNDINGS ARE SHOWING THE LOWER LEVELS DRYING OUT AS THE NIGHT PROGRESSES...WITH ZZV SOON AFTER ISSUANCE TIME...BUT PIT AND MGW NOT UNTIL AFTER DAWN. THIS APPEARS TO BE REASONABLE AS FAR AS TIMING GOES AND WILL STICK CLOSE TO THIS FOR THE FORECAST. TROUGH AXIS WILL SHIFT EASTWARD LATER THIS MORNING AND LL FLOW WILL BACK TO THE NW. THERE WILL ALSO BE ANOTHER SHOT OF CAA. THIS SHOULD PROVIDE ANOTHER INCREASE IN CLOUDS THIS AFTERNOON AND KEEP TEMPS BELOW NORMAL. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT FLURRIES ACROSS THE NW. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /05Z WEDNESDAY THROUGH SUNDAY/... A STRATOCUMULUS DECK WILL PREVAIL ACROSS ALL OF THE TERMINALS EXCEPT KZZV OVERNIGHT AS LOW-LEVEL MOISTURE BECOMES TRAPPED UNDER AN INVERSION. CEILINGS WILL PREVAIL MOSTLY AT 2500-3000FT OVERNIGHT WITH THE CLOCK DECK BEGINNING TO ERODE FROM THE WEST AROUND DAWN. CONFIDENCE IN HOW LONG CEILINGS WILL PREVAIL OVERNIGHT IS LOW AS LAMP/HRRR/NARRE-TL GUIDANCE INDICATE CEILINGS ERODING FROM THE WEST AND BREAKING ACROSS THE TERMINALS BY 06Z. THE TAFS...HOWEVER...INDICATE MVFR PREVAILING UNTIL AROUND 12Z WITH THE SUPPORT OF RECENT SATELLITE TRENDS AND MODEL SOUNDINGS. SUBSIDENCE FROM HIGH PRESSURE BUILDING IN FROM THE SOUTHWEST WILL ALLOW CEILINGS TO BREAK BY MID-MORNING WEDNESDAY WITH VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME NEAR CALM OVERNIGHT. WINDS WILL BECOME MORE WESTERLY ON WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING. .OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
315 AM EST WED NOV 28 2012 .SHORT TERM (TODAY AND TONIGHT)...TYPICAL SCENARIO FOR THE FORECAST AREA WITH A FRONTAL SYSTEM WELL SOUTHEAST OF THE REGION WITH NORTHERLY FLOW ALOFT AND LOW CLOUDS TRAPPED UNDER AN INVERSION AROUND 925 MB. APPEARS THE FORECAST HINGES ON THE THINNING CLOUD LAYER (ALREADY SEEING THE HIGH TERRAIN ALONG THE NORTH CAROLINA BORDER PEAKING THROUGH THE STRATUS). SEEMS LIKE THE RUC13 HAS THE BEST HANDLE ON THE SITUATION WITH LAYER HANGING IN THERE A WHILE LONGER THAN OTHER MODELS INDICATE...ALTHOUGH THE GFS ISN`T AS BAD AS THE WRF PROGNOSTICATION ABILITIES. IT`S ALWAYS INTERESTING BECAUSE WHEN THIS ASPECT IS INCORRECT...TEMPERATURES ARE WAY OFF. THE MODELS HAD WHAT LITTLE HEAT THE AREA PICKED UP ON TUESDAY HAPPILY RADIATING AWAY UNDER CLEARING OVERNIGHT SKIES. MODEL SUGGESTIONS INDICATE TEMPS SHOULD BE SEVERAL DEGREES COOLER TOWARD DAYBREAK ALONG WITH SOME SATURATED SURFACE CONDITIONS IN SPOTS. WENT AHEAD AND STAYED WITH A PESSIMISTIC CLEARING TREND CLOSE TO THE RUC13 IDEA WITH SOUTHEAST TENNESSEE AND SOUTHWEST NORTH CAROLINA CLEARING EARLY IN THE DAY WITH CLOUDS HANGING AROUND LONGER ACROSS SOUTHWEST VIRGINIA AND NORTHEAST TENNESSEE. BECAUSE TEMPERATURES LOOK LIKE THEY WILL START OUT WARMER THAN THEY WERE SUPPOSED TO...STAYED CLOSE TO THE MOS MAX TEMP BLEND. WOULD EXPECT HIGH PRESSURE AND DRIER AIR TO TAKE OVER FOR TONIGHT ALLOWING RADIATION AND LOW TEMPERATURES MAINLY IN THE 20S. .LONG TERM (THURSDAY THROUGH TUESDAY)...THURSDAY THROUGH SATURDAY WILL FEATURE A LOW LEVEL RIDGE OFF THE GA/SC COAST...WITH A NEARLY ZONAL FLOW ALOFT. THIS WILL KEEP THE AREA DRY AND MILD EACH DAY. A WEAK MIDLEVEL SHORTWAVE TROUGH PASSES TO OUR NORTH ON SUNDAY/SUNDAY NIGHT. SLIGHT CHANCE POPS IN NORTHERN SECTIONS LOOKS QUITE GENEROUS AS MOISTURE IS VERY LIMITED...BUT WILL BE KEPT IN THE FORECAST. THE MID-UPPER LEVEL FLOW AMPLIFIES ON MONDAY AS A DEEP TROUGH MOVES INTO THE PLAINS. WITH A DEEP SW FLOW...TEMPS WILL RISE WELL ABOVE NORMAL FOR MONDAY. MODELS ARE IN GOOD AGREEMENT WITH TIMING OF PRECIP WITH THE ASSOCIATED COLD FRONT...AND WILL ADD CHANCE POPS FOR TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 53 30 60 34 62 / 0 0 0 0 0 KNOXVILLE MCGHEE TYSON AIRPORT, TN 50 28 57 32 60 / 0 0 0 0 0 OAK RIDGE, TN 50 28 57 32 60 / 0 0 0 0 0 TRI CITIES AIRPORT, TN 47 23 55 28 59 / 0 0 0 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ 20/DGS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CST WED NOV 28 2012 .SHORT TERM...THROUGH FRIDAY NIGHT 329 AM CST WED NOV 28 2012 IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY. WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH 925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE RANGE SOUTHWEST OF I-94. PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE POTENTIAL. MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S. .LONG TERM...SATURDAY THROUGH TUESDAY 329 AM CST WED NOV 28 2012 28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI. HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO ONTARIO. && .AVIATION...THROUGH 06Z THURSDAY 1142 PM CST TUE NOV 27 2012 SKIES HAVE CLEARED OUT FOR THE TIME BEING...BUT IT APPEARS AS THOUGH A LOW LEVEL STRATUS DECK IS EXPECTED TO MOVE IN OVERNIGHT TOWARD DAY BREAK. THIS 1-2KFT BKN-OVC DECK CURRENTLY IS MAKING ITS WAY SOUTH ACROSS CENTRAL MINNESOTA AND NORTHWEST WISCONSIN WITH THE LEADING EDGE TIMED TO GET INTO KRST AROUND 10-11Z AND KLSE AROUND 13Z. SOME OF THE FORECAST GUIDANCE SUGGESTS THAT THERE MAY BE ENOUGH DRY AIR MOVING IN WITH A SURFACE RIDGE...BUT IT APPEARS THAT THIS SOLUTION MAY BE A BIT OPTIMISTIC. WITH THE CORE OF THE RIDGE NOT GETTING IN UNTIL MID DAY WEDNESDAY...HAVE OPTED TO GO WITH A MORE PESSIMISTIC MVFR CEILING FORECAST FOR 1-2KFT FOR WEDNESDAY MORNING. EXPECT THAT IT WILL BREAK UP BY LATE MORNING WITH VFR CONDITIONS PREVAILING BEYOND THAT. && .ARX WATCHES/WARNINGS/ADVISORIES... 329 AM CST WED NOV 28 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 PM CST TUE NOV 27 2012 .SHORT TERM...THROUGH FRIDAY 200 PM CST TUE NOV 27 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THIS EVENING AS WELL AS THURSDAY NIGHT INTO FRIDAY. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED RIDGING FROM THE BRITISH COLUMBIA COAST SOUTHWARD THROUGH THE WESTERN U.S....WHILE TROUGHING WAS PRESENT FROM SOUTHEAST CANADA INTO THE GREAT LAKES. IN THE NORTHWEST FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE TROUGH WAS NOTED OVER NORTHERN MINNESOTA. ISENTROPIC LIFT DEPICTED ON THE 285-295K SURFACES AHEAD OF THE SHORTWAVE HAS RESULTED IN SCATTERED-BROKEN ALTOSTRATUS ACROSS THE FORECAST AREA. FARTHER NORTH...SNOW HAS BEEN FALLING ACROSS NORTHERN MINNESOTA INTO NORTHERN WI WHERE THE DPVA AND ISENTROPIC LIFT FORCING IS STRONGEST...ALONG WITH BETTER LOW LEVEL SATURATION PER 12Z INL SOUNDING. A COLD FRONT REPRESENTING THE SHORTWAVE AT THE SURFACE EXTENDED FROM NORTHEAST MINNESOTA INTO SOUTHEAST SOUTH DAKOTA. SOUTHWEST WINDS AHEAD OF THE FRONT HAS HELPED PULL WARMER AIR INTO THE REGION...NOTED BY 925MB TEMPS THAT HAVE CLIMBED AT MPX FROM -11C AT 00Z TO -4C AT 12Z PER SOUNDINGS. READINGS HAVE CLIMBED INTO THE LOW TO MID 30S IN MOST LOCATIONS. BEHIND THE FRONT ACROSS SOUTH DAKOTA...READINGS ARE NOT THAT MUCH COOLER. HOWEVER...ACROSS SOUTHERN MANITOBA WHERE HIGH PRESSURE SITS...READINGS ARE IN THE LOWER TEENS. 925MB TEMPS IN THIS AREA ARE -14 TO -18C PER RAP ANALYSIS. TONIGHT AND WEDNESDAY...THE UPPER LEVEL PATTERN IS FORECAST TO DEAMPLIFY SOME ACROSS THE CONUS...IN RESPONSE TO A PORTION OF EAST PACIFIC TROUGHING MOVING INTO THE WESTERN U.S.. BY 00Z THURSDAY... 500MB HEIGHTS WILL HAVE RISEN NEARLY 120 METERS OVER THE FORECAST AREA. SUBSIDENCE ASSOCIATED WITH THESE HEIGHT RISES SHOULD KEEP THE MAJORITY OF THE NEXT 24 HOURS QUIET. THE ONLY CONCERN IS WITH THE SHORTWAVE OVER NORTHERN MINNESOTA DROPPING SOUTHEAST THROUGH NORTHERN WISCONSIN THIS EVENING. THE 280-285K ISENTROPIC LIFT HELPING TO PRODUCE THE SNOW ACROSS NORTHERN MINNESOTA WILL ACCOMPANY THE SHORTWAVE SOUTHEASTWARD. RIGHT NOW IT APPEARS THE BULK OF THE SNOW SHOULD STAY NORTH OF THE FORECAST AREA...PER MODEL CONSENSUS AND SHORTWAVE TRACK...BUT AM CONCERNED AT LEAST SOME FLURRIES COULD OCCUR OVER TAYLOR/CLARK. HAVE ADDED THE FLURRIES INTO THE FORECAST. EVENING SHIFT WILL NEED TO WATCH THE SNOW PROGRESSION. OTHERWISE... THE COLD FRONT LOOKS TO MOVE THROUGH MUCH OF THE FORECAST AREA BY 09Z. 925MB TEMP PROGS SUGGEST A PORTION OF THAT COLDER AIR IN SOUTHERN MANITOBA WILL MAKE IT SOUTH INTO THE FORECAST AREA...WITH TEMPS AT 12Z WEDNESDAY RANGING FROM -2C OVER NORTHEAST IOWA TO -8 TO -10C IN TAYLOR COUNTY. AS SUCH...THE COLDEST READINGS TONIGHT ARE IN TAYLOR COUNTY. THE WINDS AND SOME STRATUS CLOUDS BEHIND THE FRONT SHOULD MITIGATE THE TEMPERATURE FALL SOMEWHAT...THOUGH. THE 925MB TEMPS HOLD FAIRLY STEADY THROUGH ABOUT 18Z...DUE TO HIGH PRESSURE SLIDING ACROSS... THEN BEGIN TO CLIMB. MIXING TO THE 925MB TEMPS RESULTS IN HIGHS IN THE UPPER 20S TO NEAR 40...COLDEST ACROSS TAYLOR AND CLARK COUNTIES. THIS MIXING SHOULD BE DOABLE DESPITE SOME INCREASE IN HIGH CLOUDS DEPICTED IN THE AFTERNOON. WEDNESDAY NIGHT AND THURSDAY...SOME MORE 500MB HEIGHT RISES ARE FORECAST OVER THE AREA...IN RESPONSE TO THE WESTERN U.S. RIDGE FLATTENING OUT AND BEING PUSHED EASTWARD BY THE PORTION OF THE EAST PACIFIC TROUGH HEADING INTO THE DAKOTAS BY 00Z FRIDAY. SUBSIDENCE AGAIN ASSOCIATED WITH THESE HEIGHT RISES SHOULD BE ENOUGH TO KEEP THE AREA DRY. THIS SUBSIDENCE DOES LOOK TO CLEAR THE CIRRUS OUT WEDNESDAY NIGHT. HOWEVER...AN INCREASE IN CIRRUS IS EXPECTED ACROSS MUCH OF THE AREA ON THURSDAY AS THAT SHORTWAVE TROUGH COMES INTO THE DAKOTAS. IN ADDITION...A MASS OF LOW CLOUDS IS PROGGED TO COME INTO NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY AFTERNOON. THESE ARE IN THE WAKE OF A COLD FRONTAL PASSAGE...FORECAST TO DROP SOUTH THROUGH THE AREA MOSTLY DURING THE MORNING. 925MB TEMPS CLIMB NICELY WEDNESDAY NIGHT AHEAD OF THAT FRONT DROPPING SOUTH...TOPPING OUT BETWEEN 2C AND -2C BY 12Z. THIS WARM ADVECTION COMBINED WITH A SOUTHERLY BREEZE SHOULD HELP KEEP TEMPERATURES UP. A BLEND OF GUIDANCE SEEMS REASONABLE FOR LOWS SUGGESTING MAINLY IN THE 20S. FOR THURSDAY...925MB TEMPS FALL TO 0 TO -4C AT 18Z THURSDAY...THOUGH THE WARMER NIGHT AND SOME FILTERED SUNSHINE WILL ALLOW TEMPERATURES TO BE ABOUT 5 DEGREES WARMER THAN WEDNESDAY. THURSDAY NIGHT AND FRIDAY...THE SHORTWAVE TROUGH ACROSS THE DAKOTAS MODELS FORECAST TO COME ACROSS THE AREA FRIDAY MORNING. MODELS VARY ON STRENGTH OF THE TROUGH...WITH THE 27.12Z GFS STRONGEST AND 27.12Z NAM WEAKEST. HOWEVER...THE STRENGTH OF THE SHORTWAVE APPEARS TO HAVE LITTLE SENSIBLE IMPACT ON THE WEATHER AS THE MID-LEVELS OF THE ATMOSPHERE ARE SUGGESTED TO BE QUITE DRY. IN FACT...MUCH OF THE ACTION LOOKS TO OCCUR BELOW 850MB. THE POST-FRONTAL LOW CLOUD MASS DROPPING SOUTH THURSDAY AFTERNOON MODELS ARE IN GOOD AGREEMENT IN HAVING IT ENCOMPASS LOCATIONS FROM I-90 NORTH BY 06Z FRIDAY. THE LOW CLOUD DECK MAY EVEN DRIFT FARTHER SOUTH BETWEEN 06-12Z TO ENCOMPASS MOST OF THE AREA. THE REASON THIS IS SO IMPORTANT IS THAT ISENTROPIC LIFT PLOTS SHOW WEAK LIFT ON THE 280-285K SURFACES THURSDAY NIGHT INTO FRIDAY MORNING. THE LIFT IN THE LOW CLOUD DECK COULD RESULT IN SOME LIGHT FREEZING DRIZZLE DEVELOPING. SINCE THIS HAS BEEN A CONSISTENT SIGNAL...HAVE INCLUDED THE MENTION OF IT IN THE FORECAST. GIVEN THE IMPACTS FROM JUST A TINY BIT OF FREEZING DRIZZLE...MAY NEED AN ADVISORY AT SOME POINT. ALSO ADDED A FOG MENTION AREA WIDE FOR 06-18Z FRIDAY GIVEN THE VERY LOW CEILINGS PROGGED. CLOUDS LOOK TOUGH TO CLEAR TOO FRIDAY AFTERNOON AS A GENERAL EAST-SOUTHEAST LOW LEVEL FLOW PERSISTS. THUS...ANTICIPATING MUCH OF THIS 24 HOUR PERIOD TO BE CLOUDY. THE CLOUDS WILL LIMIT THE DIURNAL FALL AND RISE...AND IT IS WORTH NOTING THAT 925MB TEMPS CHANGE VERY LITTLE THROUGH FRIDAY SUGGESTING LITTLE IN THE WAY OF ADVECTION. THUS... TEMPERATURES SHOULD NOT CHANGE A WHOLE LOT. ONLY HAVE ABOUT A 10 DEGREE CHANGE FROM NIGHT AND DAY IN THE FORECAST. .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY 200 PM CST TUE NOV 27 2012 VERY GOOD MODEL AGREEMENT EXISTS AND REMAINS AMONGST THE 27.12Z ECMWF/GFS/UKMET/CANADIAN AND GFS ENSEMBLES THROUGH MUCH OF THE LONG TERM FORECAST...BOTH AT THE SURFACE AND ALOFT. THE UPPER LEVEL FLOW THROUGH THE SHORT TERM PERIOD THAT IS TRANSITIONING FROM NORTHWEST TO ZONAL BECOMES SOUTHWESTERLY FOR THE WEEKEND. THE FLOW THEN AMPLIFIES AS A PROGRESSIVE DEEP TROUGH MARCHES ACROSS THE WEST AND CENTRAL U.S. EARLY NEXT WEEK. MAIN PRECIPITATION TIMES OF NOTE ARE ON SATURDAY INTO SATURDAY EVENING...AS WELL AS MONDAY INTO MONDAY NIGHT. THE FIRST IS ASSOCIATED WITH A SHORTWAVE TROUGH COMING THROUGH THE SOUTHWESTERLY FLOW. A SURGE OF GULF OF MEXICO MOISTURE ACCOMPANIES THE TROUGH AS IT MOVES INTO THE AREA...ENOUGH TO LIKELY PRODUCE A LOW LEVEL STRATUS DECK AS WELL AS SOME LIGHT PRECIPITATION. RIGHT NOW MAYBE WE GET UP TO A TENTH OF AN INCH AT MOST. THE MONDAY INTO MONDAY NIGHT PERIOD IS MORE INTERESTING HAVING A DYNAMIC DEEP TROUGH COMING ACROSS. 850MB WINDS INCREASE TO 40-50 KT HELPING TO BRING 850MB DEWPOINTS UP TO 8C OR SO. ONE ISSUE IS THAT THE SATURATION AGAIN IS ALL IN THE LOW LEVELS...AND THE ATMOSPHERE IS CAPPED...THUS ANOTHER LIGHT RAIN/DRIZZLE EVENT WOULD OCCUR. OVERALL...THOUGH...CONFIDENCE IN EITHER EVENT PRODUCING WIDESPREAD QPF IS FAIRLY LOW AT THIS POINT SINCE THE DYNAMICAL FORCING IS ALL NORTH OF THE AREA. THUS...PRECIPITATION CHANCES ARE IN THE 20-40 RANGE. TEMPERATURES ARE MORE INTERESTING HERE IN THE LONG TERM PERIOD. 925MB TEMPS ARE FORECAST BETWEEN 3-7C ON SATURDAY...AS MUCH AS 6-10C ON SUNDAY PER 27.00Z/12Z ECMWF AND 10-14C BY LATE IN THE DAY MONDAY. THE INCOMING STRATUS DECK ON BOTH SATURDAY AND MONDAY WILL LIKELY HOLD BACK THE POTENTIAL FOR MIXING TO 925MB. HOWEVER...ADVECTION ALONE SHOULD BE ABLE TO PUSH READINGS INTO THE MID 40S TO LOW 50S ON SATURDAY AND INTO THE 50S EVERYWHERE ON MONDAY PER MODEL CONSENSUS. SHOULD ANY UNEXPECTED SUNSHINE OCCUR...HIGHS COULD EASILY BE HIGHER. MONDAYS FORECAST HIGHS ARE ONLY A FEW DEGREES BELOW RECORDS...59 AT ROCHESTER AND 61 AT LA CROSSE. SUNDAY HAS THE BEST OPPORTUNITY FOR SUNSHINE...AND IF THE ECMWF IS CORRECT...WE COULD EASILY CLIMB INTO THE 50S AND PERHAPS REACH 60 IN SOUTHERN AREAS. HAVE BUMPED UP HIGHS ABOVE THE CONSENSUS TO RANGE FROM THE MID 40S TO MID 50S. IT APPEARS RECORDS ON SUNDAY SHOULD BE SAFE WITH ROCHESTER AT 62 AND LA CROSSE AT 64. FOR TUESDAY...DECENT COOLING COMES IN THANKS TO THE UPPER TROUGH SLIDING INTO THE AREA. FOLLOWED THE CONSENSUS HIGHS IN THE 40S FOR NOW. && .AVIATION...THROUGH 06Z THURSDAY 1142 PM CST TUE NOV 27 2012 SKIES HAVE CLEARED OUT FOR THE TIME BEING...BUT IT APPEARS AS THOUGH A LOW LEVEL STRATUS DECK IS EXPECTED TO MOVE IN OVERNIGHT TOWARD DAY BREAK. THIS 1-2KFT BKN-OVC DECK CURRENTLY IS MAKING ITS WAY SOUTH ACROSS CENTRAL MINNESOTA AND NORTHWEST WISCONSIN WITH THE LEADING EDGE TIMED TO GET INTO KRST AROUND 10-11Z AND KLSE AROUND 13Z. SOME OF THE FORECAST GUIDANCE SUGGESTS THAT THERE MAY BE ENOUGH DRY AIR MOVING IN WITH A SURFACE RIDGE...BUT IT APPEARS THAT THIS SOLUTION MAY BE A BIT OPTIMISTIC. WITH THE CORE OF THE RIDGE NOT GETTING IN UNTIL MID DAY WEDNESDAY...HAVE OPTED TO GO WITH A MORE PESSIMISTIC MVFR CEILING FORECAST FOR 1-2KFT FOR WEDNESDAY MORNING. EXPECT THAT IT WILL BREAK UP BY LATE MORNING WITH VFR CONDITIONS PREVAILING BEYOND THAT. && .ARX WATCHES/WARNINGS/ADVISORIES... 200 PM CST TUE NOV 27 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1038 PM CST TUE NOV 27 2012 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE DROPPING SOUTHEAST OVER WESTERN WISCONSIN EARLY THIS AFTERNOON...AND IS KICKING OFF SNOW SHOWERS OVER THE NW CORNER OF THE STATE. A FEW SNOW SHOWERS LOOK RATHER BEEFY ON RADAR...AND AN OBSERVATION AT HAYWARD DROPPED VSBYS DOWN TO A QUARTER MILE BRIEFLY. WILL BE ON THE LOOK OUT FOR A HISA EVENT THIS AFTERNOON. COLD FRONT IS TRAILING THE LEAD SHORTWAVE...AND IS POSITIONED FROM THE ARROWHEAD OF MINNESOTA TO NORTHERN SOUTH DAKOTA. A WIDESPREAD LOW STRATUS DECK EXISTS IMMEDIATELY BEHIND THIS FRONT...AND A FEW FLURRIES HAVE BEEN NOTED ON THE OBS THERE TOO. AS SHORTWAVE ACTIVITY AND THE COLD FRONT CROSS THE REGION TONIGHT...CLOUDS AND PRECIP CHANCES ARE THE MAIN FORECAST CONCERNS. TONIGHT...WEAK SHORTWAVE ACTIVITY WILL SWING ACROSS THE REGION TONIGHT AND PUSH A COLD FRONT ACROSS THE AREA. THOUGH MOISTURE IS GENERALLY LACKING...MOISTURE IS GREATER TO THE NORTH. RADARS SUGGEST N-C WISCONSIN WILL SEE LIKELY SNOW SHOWERS THIS EVENING SO WILL RAISE POPS A BIT. NOT SURE HOW FAR SOUTH TO BRING A MENTION OF FLURRIES...BUT NORTH OF ROUTE 29 SEEMS LIKE A LOGICAL DIVIDER BASED ON RADAR TRENDS. BEHIND THE FRONT...A LOW STRATUS DECK HAS BEEN ADVANCING SOUTHEAST. MODELS SCOUR OUT THE LOW LEVEL MOISTURE TONIGHT AND SUGGEST THIS STRATUS DECK MAY ONLY REACH N-C WISCONSIN. GIVEN THE SOLID LOOK TO THE STRATUS AND THE COLD ADVECTION TO TAKE PLACE...THINK THIS IS TOO OPTIMISTIC AND WILL BRING THE STRATUS DECK INTO CENTRAL WISCONSIN AS WELL. BY THE TIME IT GETS THERE LATE TONIGHT...ENOUGH DRY AIR AND DOWNSLOPING SHOULD KEEP THE STRATUS FROM REACHING NE AND E-C WISCONSIN. NORTHWEST WINDS WILL KEEP SNOW SHOWERS AND FLURRIES GOING OVER VILAS COUNTY THROUGH THE NIGHT HOWEVER. A STRONGER PRESSURE GRADIENT SHOULD KEEP THE BL MIXED ENOUGH TO GO WITH WARMER TEMPS COMPARED TO LAST NIGHT. WILL GO WITH LOW TEENS NORTH TO NEAR 20 SE. WEDNESDAY...PRETTY QUIET AS HIGH PRESSURE RIDGE AXIS WORKS ACROSS THE STATE. BACKING LOW LEVEL WINDS WILL FORCE LAKE CLOUDS TO LIFT OFF TO THE NORTHEAST AND AWAY FROM N-C WISCONSIN DURING THE MORNING. IF LOW STRATUS DOES STICK AROUND INTO WEDNESDAY MORNING...THINK THE INCOMING RIDGE AXIS WILL CAUSE ANY CLOUDS TO BREAK UP EARLY IN THE PERIOD. MOST OF THE AREA SHOULD SEE MOSTLY SUNNY CONDITIONS FOR MUCH OF THE DAY. HIGHS RANGING FROM THE MID 20S NORTH TO LOWER 30S SOUTH. .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. WINTER IS SLOW TO ARRIVE THIS YEAR AND THE MEDIUM RANGE MODELS SUGGEST THAT THE MILD WEATHER PATTERN WILL CONTINUE. DRY NORTHWEST FLOW IS EXPECTED THROUGH THURSDAY WITH TEMPERATURES RISING ABOVE NORMAL FOR THIS TIME OF THE YEAR. UPPER FLOW IS FORECAST TO BECOME ZONAL FRIDAY THROUGH SUNDAY WITH SOME OVERRUNNING LIGHT SNOW...DRIZZLE OR FREEZING DRIZZLE THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH THE FLOW. MOISTURE IS SHALLOW AND NOT VERY ABUNDANT SO DO NOT EXPECT MUCH. A MORE SIGNIFICANT SHORTWAVE IS EXPECTED SATURDAY AFTERNOON OR EVENING WHICH SHOULD HAVE A BIT MORE MOISTURE AS WELL. TEMPERATURES WILL BE WELL ABOVE FREEZING SO WHATEVER FALLS SHOULD BE RAIN. UPPER RIDGE REALLY BUILDS MONDAY AND SOUTHERLY LOW LEVEL FLOW INCREASES TOO. 925MB TEMPERATURES FORECAST TO RISE TO +10C MONDAY AFTERNOON AND EVENING WHICH COULD HELP DRIVE TEMPERATURES INTO THE 50S IF THERE IS ANY SUNSHINE AT ALL. A COLD FRONT WILL MOVE THROUGH MONDAY NIGHT AND BRING SLIGHTLY COOLER AIR FOR TUESDAY. && .AVIATION...SCT LAKE-EFFECT SNOW SHOWERS OR FLURRIES WILL LINGER OVER FAR NORTH CENTRAL WI OVERNIGHT...THEN COME TO AN END BY WEDS MORNING. MVFR CIGS ARE EXPECTED OVER NORTH CENTRAL AND CENTRAL WI...ALTHOUGH CLEARING IS EXPECTED THERE TOWARD DAYBREAK. HIGH PRESSURE WILL BRING VFR CONDITIONS ON WEDNESDAY. SOME LLWS MAY DEVELOP AT RHI/AUW/CWA ON WEDS EVENING...AS SW WINDS INCREASE TO 35 KNOTS AT 1000-1500 FT AGL. KIECKBUSCH && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
ISSUED BY NATIONAL WEATHER SERVICE UPTON NY 949 AM EST WED NOV 28 2012 .SYNOPSIS... DRIER AND UNSEASONABLY COLD WEATHER ARRIVES LATE TODAY AND LINGERS THROUGH FRIDAY. A WARM FRONT WILL BRING MUCH MILDER WEATHER FOR EARLY NEXT WEEK...WITH A CHANCE FOR SOME RAIN LATE SUNDAY INTO EARLY MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST ON TRACK THIS MORNING. MINOR TWEAKS TO BRING TEMPERATURES BACK IN LINE WITH OBSERVED TRENDS. 28/06Z GFS/NAM AND 28/10Z RAP ALL INDICATE POTENTIAL FOR OCEAN-EFFECT PRECIPITATION TO DEVELOP IN THE NORTHEAST FLOW ON THE BACKSIDE OF THE DEPARTING LOW PRESSURE. MADE MINOR TWEAKS TO POPS TO REFLECT THIS THOUGHT. PREVIOUS DISCUSSION... EXPECT LEFTOVER PRECIP ACROSS SE MA...CAPE COD AND THE ISLANDS TO PUSH OFFSHORE BY 13Z-14Z AS LOW PRES PUSHES OFFSHORE. MOST OF THE HIGH CLOUDS HAVE MOVED OFFSHORE AS SEEN ON IR SATELLITE. STILL SEE LOWER CLOUDS ACROSS MOST AREAS AT 09Z. SOME LEFTOVER SHOWERS MAY LINGER ALONG THE E COAST THROUGH MIDDAY...THOUGH SHOULD SHIFT OFFSHORE DURING THE AFTERNOON. CLOUDS WILL LIKELY LINGER ACROSS CENTRAL AND EASTERN AREAS THROUGH A GOOD PORTION OF THE DAY... WHILE THEY BREAK ACROSS THE WEST AS HIGH PRES RIDGE BEGINS TO BUILD ACROSS THE REGION. MAY SEE SOME GUSTY NW WINDS ACROSS THE E COAST THIS MORNING...THEN WILL DIMINISH. EXPECTING DAYTIME HIGHS MAINLY IN THE MID-UPPER 30S ACROSS S NH...RANGING TO THE MID 40S ALONG THE S COAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... TONIGHT... HIGH PRESSURE WILL BUILD ACROSS THEN TO THE S OF THE REGION DURING THE NIGHT. PRES GRADIENT WILL INCREASE AS SHOT OF COLDER AIR WILL WORK IN DURING THE NIGHT...SO WILL SEE SOME WIND GUSTS PICKING UP MAINLY AFTER MIDNIGHT ALONG THE IMMEDIATE E COAST AS WELL AS THE CAPE AND ISLANDS. EXPECT OVERNIGHT LOWS MAINLY IN THE 20S...EXCEPT THE LOWER-MID 30S ACROSS THE MID AND OUTER CAPE AND ISLANDS. THURSDAY... HIGH PRES SETTLES ACROSS THE MID ATLC STATES...WINDS WILL DIMINISH AS THEY BACK TO THE W AND SW DURING THE AFTERNOON. EXPECT DRY CONDITIONS WITH THE HIGH TO THE S. DAYTIME HIGHS WILL BE IN THE UPPER 30S TO MID 40S...WHICH WILL STILL BE UP TO 5 DEGREES BELOW SEASONAL NORMALS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * DRY AND UNSEASONABLY COLD THURSDAY AND FRIDAY * A FEW PASSING RAIN/SNOW SHOWERS POSSIBLE SATURDAY...BUT NOT A WASHOUT * MUCH MILDER EARLY NEXT WEEK WITH SOME RAIN SHOWERS POSSIBLE LATE SUNDAY/EARLY MON 28/00Z GUIDANCE CONTINUES TO BE IN VERY GOOD AGREEMENT OVER THIS PORTION OF THE FORECAST. JUST ABOUT ALL MODELS MAINTAIN A PROGRESSIVE MID-LEVEL FLOW PATTERN UNTIL THE MIDDLE OF NEXT WEEK. AS SUCH EXPECTING ONLY WEAK SYNOPTIC SYSTEMS TO IMPACT OUR REGION AT TIMES...MAINLY FRONTS AS THE PARENT LOW PRESSURES STAY WELL AWAY FROM OUR REGION. DETAILS... THURSDAY NIGHT AND FRIDAY...A FAIRLY STRONG COLD FRONT WILL MOVE THROUGH THE REGION...BUT IT APPEARS TOO DRY FOR ANY PRECIPITATION. THIS FRONT WILL RESULT IN THE COLDEST WEATHER SO FAR THIS SEASON. A STRONG HIGH PRESSURE OVER EASTERN CANADA WILL RESULT IN NORTHERLY SURFACE WINDS FRIDAY. THIS SHOULD RESULT IN POOR MIXING AND KEEP THE SHALLOW COLD AIR IN PLACE. SATURDAY...HIGH PRESSURE OVER QUEBEC WILL SLOWLY MOVE EAST INTO THE CANADIAN MARITIMES AS A WARM FRONT TRIES TO APPROACH THE REGION. THIS FRONT MAY BE ENOUGH TO TRIGGER A FEW RAIN/SNOW SHOWERS...BUT CERTAINLY NOT EXPECTING A WASHOUT OR A SIGNIFICANT PRECIPITATION EVENT WITH SUCH DRY LOW LEVELS. MAY HAVE TO WATCH FOR SOME SLICK SPOTS ON THE ROADS IF THERE ENDS UP BEING SOME LIGHT FROZEN PRECIPITATION...BUT THAT REMAINS UNCERTAIN AT THIS TIME. SUNDAY THROUGH TUESDAY...MUCH MILDER MID-LEVEL TEMPERATURES SHOULD ARRIVE BEHIND A WARM FRONT....RESULTING IN SIGNIFICANTLY MILDER TEMPERATURES EARLY NEXT WEEK. HIGHS SHOULD TOP OUT WELL INTO THE 40S IF NOT THE 50S OVER THIS TIME. A FRONT MAY BRING A ROUND OF RAIN SHOWERS TO THE REGION SOMETIME LATE SUNDAY INTO EARLY MONDAY...BUT THE REST OF THE TIME LOOKS DRY. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...MODERATE CONFIDENCE TODAY...HIGH CONFIDENCE TONIGHT AND THURSDAY. TODAY...MVFR CIGS MAY LINGER ACROSS CAPE COD AND THE ISLANDS THROUGH MIDDAY. MAY ALSO SEE AREAS OF IFR CONDITIONS TOWARD EAST COAST THIS MORNING IN OCEAN-EFFECT SHOWERS. MAY SEE N-NW GUSTS AROUND 20 KT ALONG E COAST DURING THE AFTERNOON. TONIGHT AND THURSDAY... MAINLY VFR CONDITIONS. W-NW WINDS GUSTING TO AROUND 25 KT ACROSS E COASTAL AREAS LATE TONIGHT AND EARLY THU...THEN BACKING TO W-SW AND DIMINISHING. KBOS TAF...HIGH CONFIDENCE IN TRENDS BUT MODERATE CONFIDENCE IN TIMING. KBDL TAF...MODERATE TO HIGH CONFIDENCE. EXPECT VFR CONDITIONS THROUGH THU WITH FEW-SCT MID AND HIGH CLOUDS. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. MAY SEE A PERIOD OF MVFR CONDITIONS SATURDAY AS A WARM FRONT WORKS TOWARD THE REGION WITH A FEW RAIN/SNOW SHOWERS. ANOTHER SHOT AT MVFR CONDITIONS WILL BE LATE SUNDAY/SUNDAY NIGHT WITH A ROUND OF RAIN SHOWERS AHEAD OF A COLD FRONT. && .MARINE... MODERATE TO HIGH CONFIDENCE. TODAY...EXPECT WINDS TO BACK TO N-NW DURING THE DAY AS HIGH PRES BUILDS OUT OF THE APPALACHIANS. WILL SEE SOME GUSTS UP TO 20-25 KT ACROSS THE EASTERN WATERS EARLY...THEN WILL DIMINISH. SEAS WILL REMAIN AOA 5 FT...SO HAVE KEPT SMALL CRAFT GOING. TONIGHT-THURSDAY...NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS THE WATERS LATE TONIGHT INTO THURSDAY MORNING. EXTENDED THE SMALL CRAFT THROUGH THURSDAY. WAVE MODELS INDICATING AN INCREASE IN SEAS...POSSIBLY UP TO 7-8 FT...ON THE OUTER WATERS WITH THE GUSTY WINDS WHICH MAY REACH 30 KT. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... MODERATE TO HIGH CONFIDENCE IN CONTINUED PERIODS OF 25 KNOT WIND GUSTS. FIRST IN A COLD AIR ADVECTION PATTERN FROM THE NORTH AND EAST THROUGH SATURDAY...THEN PERHAPS FROM THE SOUTHWEST BY SUNDAY BEHIND A WARM FRONT. SMALL CRAFT ADVISORY HEADLINES WILL LIKELY BE NEEDED THURSDAY NIGHT INTO FRIDAY...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ250- 254>256. SMALL CRAFT ADVISORY FROM 1 AM TO NOON EST THURSDAY FOR ANZ251. && $$ SYNOPSIS... NEAR TERM...99 SHORT TERM... LONG TERM... AVIATION... MARINE... EQUIPMENT...
AREA FORECAST DISCUSSION...UPDATED
NWS TAUNTON MA
744 AM EST WED NOV 28 2012 .SYNOPSIS... DRIER AND UNSEASONABLY COLD WEATHER ARRIVES LATE TODAY AND LINGERS THROUGH FRIDAY. A WARM FRONT WILL BRING MUCH MILDER WEATHER FOR EARLY NEXT WEEK...WITH A CHANCE FOR SOME RAIN LATE SUNDAY INTO EARLY MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 730 AM UPDATE... MINOR TWEAKS TO BRING TEMPERATURES BACK IN LINE WITH OBSERVED TRENDS. 28/06Z GFS/NAM AND 28/10Z RAP ALL INDICATE POTENTIAL FOR OCEAN-EFFECT PRECIPITATION TO DEVELOP IN THE NORTHEAST FLOW ON THE BACKSIDE OF THE DEPARTING LOW PRESSURE. MADE MINOR TWEAKS TO POPS TO REFLECT THIS THOUGHT. PREVIOUS DISCUSSION... EXPECT LEFTOVER PRECIP ACROSS SE MA...CAPE COD AND THE ISLANDS TO PUSH OFFSHORE BY 13Z-14Z AS LOW PRES PUSHES OFFSHORE. MOST OF THE HIGH CLOUDS HAVE MOVED OFFSHORE AS SEEN ON IR SATELLITE. STILL SEE LOWER CLOUDS ACROSS MOST AREAS AT 09Z. SOME LEFTOVER SHOWERS MAY LINGER ALONG THE E COAST THROUGH MIDDAY...THOUGH SHOULD SHIFT OFFSHORE DURING THE AFTERNOON. CLOUDS WILL LIKELY LINGER ACROSS CENTRAL AND EASTERN AREAS THROUGH A GOOD PORTION OF THE DAY... WHILE THEY BREAK ACROSS THE WEST AS HIGH PRES RIDGE BEGINS TO BUILD ACROSS THE REGION. MAY SEE SOME GUSTY NW WINDS ACROSS THE E COAST THIS MORNING...THEN WILL DIMINISH. EXPECTING DAYTIME HIGHS MAINLY IN THE MID-UPPER 30S ACROSS S NH...RANGING TO THE MID 40S ALONG THE S COAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... TONIGHT... HIGH PRESSURE WILL BUILD ACROSS THEN TO THE S OF THE REGION DURING THE NIGHT. PRES GRADIENT WILL INCREASE AS SHOT OF COLDER AIR WILL WORK IN DURING THE NIGHT...SO WILL SEE SOME WIND GUSTS PICKING UP MAINLY AFTER MIDNIGHT ALONG THE IMMEDIATE E COAST AS WELL AS THE CAPE AND ISLANDS. EXPECT OVERNIGHT LOWS MAINLY IN THE 20S...EXCEPT THE LOWER-MID 30S ACROSS THE MID AND OUTER CAPE AND ISLANDS. THURSDAY... HIGH PRES SETTLES ACROSS THE MID ATLC STATES...WINDS WILL DIMINISH AS THEY BACK TO THE W AND SW DURING THE AFTERNOON. EXPECT DRY CONDITIONS WITH THE HIGH TO THE S. DAYTIME HIGHS WILL BE IN THE UPPER 30S TO MID 40S...WHICH WILL STILL BE UP TO 5 DEGREES BELOW SEASONAL NORMALS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGHLIGHTS... * DRY AND UNSEASONABLY COLD THURSDAY AND FRIDAY * A FEW PASSING RAIN/SNOW SHOWERS POSSIBLE SATURDAY...BUT NOT A WASHOUT * MUCH MILDER EARLY NEXT WEEK WITH SOME RAIN SHOWERS POSSIBLE LATE SUNDAY/EARLY MON 28/00Z GUIDANCE CONTINUES TO BE IN VERY GOOD AGREEMENT OVER THIS PORTION OF THE FORECAST. JUST ABOUT ALL MODELS MAINTAIN A PROGRESSIVE MID-LEVEL FLOW PATTERN UNTIL THE MIDDLE OF NEXT WEEK. AS SUCH EXPECTING ONLY WEAK SYNOPTIC SYSTEMS TO IMPACT OUR REGION AT TIMES...MAINLY FRONTS AS THE PARENT LOW PRESSURES STAY WELL AWAY FROM OUR REGION. DETAILS... THURSDAY NIGHT AND FRIDAY...A FAIRLY STRONG COLD FRONT WILL MOVE THROUGH THE REGION...BUT IT APPEARS TOO DRY FOR ANY PRECIPITATION. THIS FRONT WILL RESULT IN THE COLDEST WEATHER SO FAR THIS SEASON. A STRONG HIGH PRESSURE OVER EASTERN CANADA WILL RESULT IN NORTHERLY SURFACE WINDS FRIDAY. THIS SHOULD RESULT IN POOR MIXING AND KEEP THE SHALLOW COLD AIR IN PLACE. SATURDAY...HIGH PRESSURE OVER QUEBEC WILL SLOWLY MOVE EAST INTO THE CANADIAN MARITIMES AS A WARM FRONT TRIES TO APPROACH THE REGION. THIS FRONT MAY BE ENOUGH TO TRIGGER A FEW RAIN/SNOW SHOWERS...BUT CERTAINLY NOT EXPECTING A WASHOUT OR A SIGNIFICANT PRECIPITATION EVENT WITH SUCH DRY LOW LEVELS. MAY HAVE TO WATCH FOR SOME SLICK SPOTS ON THE ROADS IF THERE ENDS UP BEING SOME LIGHT FROZEN PRECIPITATION...BUT THAT REMAINS UNCERTAIN AT THIS TIME. SUNDAY THROUGH TUESDAY...MUCH MILDER MID-LEVEL TEMPERATURES SHOULD ARRIVE BEHIND A WARM FRONT....RESULTING IN SIGNIFICANTLY MILDER TEMPERATURES EARLY NEXT WEEK. HIGHS SHOULD TOP OUT WELL INTO THE 40S IF NOT THE 50S OVER THIS TIME. A FRONT MAY BRING A ROUND OF RAIN SHOWERS TO THE REGION SOMETIME LATE SUNDAY INTO EARLY MONDAY...BUT THE REST OF THE TIME LOOKS DRY. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...MODERATE CONFIDENCE TODAY...HIGH CONFIDENCE TONIGHT AND THURSDAY. TODAY...MVFR CIGS MAY LINGER ACROSS CAPE COD AND THE ISLANDS THROUGH MIDDAY. MAY ALSO SEE AREAS OF IFR CONDITIONS TOWARD EAST COAST THIS MORNING IN OCEAN-EFFECT SHOWERS. MAY SEE N-NW GUSTS AROUND 20 KT ALONG E COAST DURING THE AFTERNOON. TONIGHT AND THURSDAY... MAINLY VFR CONDITIONS. W-NW WINDS GUSTING TO AROUND 25 KT ACROSS E COASTAL AREAS LATE TONIGHT AND EARLY THU...THEN BACKING TO W-SW AND DIMINISHING. KBOS TAF...HIGH CONFIDENCE IN TRENDS BUT MODERATE CONFIDENCE IN TIMING. KBDL TAF...MODERATE TO HIGH CONFIDENCE. VFR CIGS/MVFR VSBYS EARLY. EXPECT VSBYS TO IMPROVE TO VFR BY SUNRISE. EXPECT VFR CONDITIONS THROUGH THU WITH FEW-SCT MID AND HIGH CLOUDS. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. MAY SEE A PERIOD OF MVFR CONDITIONS SATURDAY AS A WARM FRONT WORKS TOWARD THE REGION WITH A FEW RAIN/SNOW SHOWERS. ANOTHER SHOT AT MVFR CONDITIONS WILL BE LATE SUNDAY/SUNDAY NIGHT WITH A ROUND OF RAIN SHOWERS AHEAD OF A COLD FRONT. && .MARINE... MODERATE TO HIGH CONFIDENCE. TODAY...EXPECT WINDS TO BACK TO N-NW DURING THE DAY AS HIGH PRES BUILDS OUT OF THE APPALACHIANS. WILL SEE SOME GUSTS UP TO 20-25 KT ACROSS THE EASTERN WATERS EARLY...THEN WILL DIMINISH. SEAS WILL REMAIN AOA 5 FT...SO HAVE KEPT SMALL CRAFT GOING. TONIGHT-THURSDAY...NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS THE WATERS LATE TONIGHT INTO THURSDAY MORNING. EXTENDED THE SMALL CRAFT THROUGH THURSDAY. WAVE MODELS INDICATING AN INCREASE IN SEAS...POSSIBLY UP TO 7-8 FT...ON THE OUTER WATERS WITH THE GUSTY WINDS WHICH MAY REACH 30 KT. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... MODERATE TO HIGH CONFIDENCE IN CONTINUED PERIODS OF 25 KNOT WIND GUSTS. FIRST IN A COLD AIR ADVECTION PATTERN FROM THE NORTH AND EAST THROUGH SATURDAY...THEN PERHAPS FROM THE SOUTHWEST BY SUNDAY BEHIND A WARM FRONT. SMALL CRAFT ADVISORY HEADLINES WILL LIKELY BE NEEDED THURSDAY NIGHT INTO FRIDAY...ESPECIALLY ACROSS THE OUTER COASTAL WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ250. SMALL CRAFT ADVISORY FROM 1 AM TO NOON EST THURSDAY FOR ANZ251. SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ254>256. && $$ SYNOPSIS...BELK/EVT NEAR TERM...BELK/EVT SHORT TERM...EVT LONG TERM...BELK AVIATION...BELK/EVT MARINE...BELK/EVT
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
625 AM EST Wed Nov 28 2012 .NEAR TERM [Today and Tonight]... Updated at: 515 am EST The Dense Fog Advisory that was previously in effect for portions of the area has been cancelled. Between 04z and 08z there were a fair number of observations in SW Georgia that had visibilities at 1/4SM or 1/2SM, but a recent increase in winds has caused visibility to improve areawide. Despite a small chance that a couple of the observations could see visibility dip briefly in patchy fog early this morning, the probability no longer seems high enough to warrant an advisory. A frontal inversion should keep the mixed layer relatively shallow today, which will keep temperatures cooler than the +10 to +11C 850mb temperatures would suggest. In shallow CAA regimes just after a cold front passage, the morning temperatures tend to be slower to increase than the typical diurnal curve. The temperature curve was nudged down in the morning to account for this. However, with breaks of sun likely to develop by afternoon we are still expecting highs to get into the 60s just about everywhere. For tonight, some MOS guidance is still indicating lows close to freezing in our SE Alabama zones. However, it would take a very strong inversion to produce lows of those values given the temperature profile in the 925-850mb layer. That is not expected to be the case, and so despite clear skies and lighter winds the lows should mainly stay in the 37-42 degree range. These types of lows would also prevent frost in most spots. && .SHORT TERM [Thursday Through Friday]... A lingering low-level ridge of high pressure along the Atlantic seaboard will keep east to northeast flow in place across much of the east coast. This pattern should prevent rapid modification of the cooler air mass that will be in place. However, highs should increase a couple degrees each day at the end of the work week with mostly sunny skies and a deeper mixed layer each afternoon. && .LONG TERM [Friday Night through next Wednesday]... Guidance is in good agreement that the flow across the CONUS will continue to be fast and primarily zonal through early next week. The primary jet and any associated disturbances are forecast to remain well north of the forecast area through next Tuesday, before digging southward by midweek and driving a cold front towards the Gulf Coast. Before this trough digs southward, expect an upper ridge to develop over the gulf and nose northeast across the area. The impact of this upper pattern will be for warmer than normal temperatures into early next week, with minimal rain chances. Expect highs in the mid 70s with lows generally in the lower 50s. Rain chances will be introduced for late Tuesday into Wednesday ahead of the approaching cold front. && .AVIATION [through 12z Thursday]... Low CIGS & fog currently dominate the region with IFR conditions ongoing at all terminals. Expect conditions to improve after sunrise, with the fog burning off before cigs lift. VFR conditions are anticipated by afternoon and will continue through tonight with light north to northeast winds. && .MARINE... With the 4am CWF issuance, we plan to maintain the SCEC headline across all but the far eastern nearshore zones (Apalachee Bay and along Taylor and Dixie Counties) through mid-morning. The latest buoy and tower observations continue to indicate winds around 15-16 knots over the bulk of the coastal waters, with a few gusts to around 20 knots. A 0315z ASCAT pass also showed a sizable swath of 15-20 knot winds, which matched well with RAP and local WRF (which were used as the basis for the updated wind forecast in the first 12 hours). Winds quickly veer to the east by tonight as high pressure settles into the Southeast, setting up the typical surges of easterly winds at night over the next few days. && .FIRE WEATHER... A slightly drier airmass will filter into the region today in the wake of a cold front. However, humidity values are not forecast to reach critical levels, and ERC values should remain below thresholds following Tuesdays rainfall. By Thursday into the weekend, easterly flow is forecast to bring in enough Atlantic moisture to keep RH values above critical levels. No Red Flag conditions are expected through the end of the work week. && .HYDROLOGY... Rainfall totals over the past 24 hours ranged from nil or trace amounts near the Suwannee River in the eastern Florida Big Bend, to around an inch in southeast Alabama. These rain amounts are not expected to cause any notable changes in the area rivers. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 67 39 70 45 74 / 0 0 0 10 10 Panama City 66 45 68 51 72 / 0 0 0 10 10 Dothan 64 38 67 45 71 / 0 0 0 10 10 Albany 63 37 68 43 72 / 0 0 0 10 10 Valdosta 66 41 70 47 73 / 0 0 0 10 10 Cross City 71 43 74 47 76 / 0 0 0 10 10 Apalachicola 66 47 67 53 71 / 0 0 0 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR AND SHORT TERM...Lamers LONG TERM...Camp AVIATION...Camp MARINE...Lamers FIRE WEATHER...Camp HYDROLOGY...Lamers
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
515 AM EST Wed Nov 28 2012 .NEAR TERM [Today and Tonight]... Updated at: 515 am EST The Dense Fog Advisory that was previously in effect for portions of the area has been cancelled. Between 04z and 08z there were a fair number of observations in SW Georgia that had visibilities at 1/4SM or 1/2SM, but a recent increase in winds has caused visibility to improve areawide. Despite a small chance that a couple of the observations could see visibility dip briefly in patchy fog early this morning, the probability no longer seems high enough to warrant an advisory. A frontal inversion should keep the mixed layer relatively shallow today, which will keep temperatures cooler than the +10 to +11C 850mb temperatures would suggest. In shallow CAA regimes just after a cold front passage, the morning temperatures tend to be slower to increase than the typical diurnal curve. The temperature curve was nudged down in the morning to account for this. However, with breaks of sun likely to develop by afternoon we are still expecting highs to get into the 60s just about everywhere. For tonight, some MOS guidance is still indicating lows close to freezing in our SE Alabama zones. However, it would take a very strong inversion to produce lows of those values given the temperature profile in the 925-850mb layer. That is not expected to be the case, and so despite clear skies and lighter winds the lows should mainly stay in the 37-42 degree range. These types of lows would also prevent frost in most spots. && .SHORT TERM [Thursday Through Friday]... A lingering low-level ridge of high pressure along the Atlantic seaboard will keep east to northeast flow in place across much of the east coast. This pattern should prevent rapid modification of the cooler air mass that will be in place. However, highs should increase a couple degrees each day at the end of the work week with mostly sunny skies and a deeper mixed layer each afternoon. && .LONG TERM [Friday Night through next Wednesday]... Guidance is in good agreement that the flow across the CONUS will continue to be fast and primarily zonal through early next week. The primary jet and any associated disturbances are forecast to remain well north of the forecast area through next Tuesday, before digging southward by midweek and driving a cold front towards the Gulf Coast. Before this trough digs southward, expect an upper ridge to develop over the gulf and nose northeast across the area. The impact of this upper pattern will be for warmer than normal temperatures into early next week, with minimal rain chances. Expect highs in the mid 70s with lows generally in the lower 50s. Rain chances will be introduced for late Tuesday into Wednesday ahead of the approaching cold front. && .AVIATION [through 06z Thursday]... Low CIGS & fog currently dominate the region with IFR conditions ongoing at all terminals. Expect conditions to occasionally reach airport minimums until after sunrise. Thereafter, the overcast should gradually burn off, with VFR conditions anticipated by afternoon and continuing into Wednesday night. && .MARINE... With the 4am CWF issuance, we plan to maintain the SCEC headline across all but the far eastern nearshore zones (Apalachee Bay and along Taylor and Dixie Counties) through mid-morning. The latest buoy and tower observations continue to indicate winds around 15-16 knots over the bulk of the coastal waters, with a few gusts to around 20 knots. A 0315z ASCAT pass also showed a sizable swath of 15-20 knot winds, which matched well with RAP and local WRF (which were used as the basis for the updated wind forecast in the first 12 hours). Winds quickly veer to the east by tonight as high pressure settles into the Southeast, setting up the typical surges of easterly winds at night over the next few days. && .FIRE WEATHER... A slightly drier airmass will filter into the region today in the wake of a cold front. However, humidity values are not forecast to reach critical levels, and ERC values should remain below thresholds following Tuesdays rainfall. By Thursday into the weekend, easterly flow is forecast to bring in enough Atlantic moisture to keep RH values above critical levels. No Red Flag conditions are expected through the end of the work week. && .HYDROLOGY... Rainfall totals over the past 24 hours ranged from nil or trace amounts near the Suwannee River in the eastern Florida Big Bend, to around an inch in southeast Alabama. These rain amounts are not expected to cause any notable changes in the area rivers. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 67 39 70 45 74 / 0 0 0 10 10 Panama City 66 45 68 51 72 / 0 0 0 10 10 Dothan 64 38 67 45 71 / 0 0 0 10 10 Albany 63 37 68 43 72 / 0 0 0 10 10 Valdosta 66 41 70 47 73 / 0 0 0 10 10 Cross City 71 43 74 47 76 / 0 0 0 10 10 Apalachicola 66 47 67 53 71 / 0 0 0 10 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR AND SHORT TERM...Lamers LONG TERM...Camp AVIATION...Camp MARINE...Lamers FIRE WEATHER...Camp HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS JACKSON KY
1029 AM EST WED NOV 28 2012 .UPDATE... ISSUED AT 1029 AM EST WED NOV 28 2012 MADE SOME MODIFICATIONS TO THE TEMPERATURE AND CLOUD COVER FORECAST FOR THE REST OF TODAY. THE LATEST SATELLITE IMAGERY CLEARLY SHOWS THAT CLOUD COVER HAS BEEN DISSIPATING MORE QUICKLY THIS MORNING THAN THE PREVIOUS FORECAST WAS INDICATING. THAT BEING SAID...SPED UP THE TIMING OF CLOUD DISSIPATION TODAY BY 3 OR 4 HOURS TO REFLECT THE LATEST TRENDS. WITH OUR WESTERN AND CENTRAL COUNTIES CLEARING OFF MORE QUICKLY...ALSO INCREASED TODAYS HIGH TEMPERATURES FOR MOST OF THE FORECAST AREA...TO ACCOUNT FOR THE GREATER THAN EXPECTED AMOUNT OF SUNSHINE. TODAYS HIGHS ARE NOW EXPECTED TO INCREASE INTO THE LOWER 40S ACROSS MOST OF THE AREA...WITH ONLY A FEW READINGS IN THE UPPER 30S EXPECTED IN THE HIGHER TERRAIN ALONG THE VIRGINIA BORDER. THE REST OF THE FORECAST WAS IN GOOD SHAPE. UPDATE ISSUED AT 629 AM EST WED NOV 28 2012 FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 233 AM EST WED NOV 28 2012 EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY. THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY SKIES. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 203 AM EST WED NOV 28 2012 SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS. THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND. UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN ON TUE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 629 AM EST WED NOV 28 2012 LOW CLOUDS ARE STARTING TO SHOW MORE HOLES EARLY THIS MORNING AND I WOULD EXPECT THE STRATUS TO ERODE DURING THE REMAINDER OF THE MORNING HOURS...GIVING WAY TO VFR CONDITIONS FOR THE AFTERNOON AND TONIGHT. VFR CONDITIONS SHOULD THEN CONTINUE FOR THE BALANCE OF THE WEEK. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...KAS LONG TERM....DUSTY AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
629 AM EST WED NOV 28 2012 .UPDATE... ISSUED AT 629 AM EST WED NOV 28 2012 FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 233 AM EST WED NOV 28 2012 EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY. THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY SKIES. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 203 AM EST WED NOV 28 2012 SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS. THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND. UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN ON TUE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 629 AM EST WED NOV 28 2012 LOW CLOUDS ARE STARTING TO SHOW MORE HOLES EARLY THIS MORNING AND I WOULD EXPECT THE STRATUS TO ERODE DURING THE REMAINDER OF THE MORNING HOURS...GIVING WAY TO VFR CONDITIONS FOR THE AFTERNOON AND TONIGHT. VFR CONDITIONS SHOULD THEN CONTINUE FOR THE BALANCE OF THE WEEK. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...KAS LONG TERM....DUSTY AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
823 AM EST WED NOV 28 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... PER RECENT SURFACE AND SATELLITE DATA...HAVE AGAIN ADJUSTED CLOUD COVERAGE...INDICATING A MOSTLY CLOUDY DAY ACROSS THE UPPER OHIO VALLEY. SREF AND RAP MODEL OUTPUT CONTINUE TO SHOW A SECONDARY COLD FRONT PASSING EASTWARD THROUGH THE GREAT LAKES TODAY. ASSOCIATED SHOWERS SHOULD PASS NORTH OF I-80 BUT REINFORCED SHALLOW COLD POOL INSTABILITY WILL MAINTAIN CLOUDS ACROSS THE UPPER OHIO VALLEY TODAY. MADE ONLY SMALL ADJUSTMENTS TO TEMPERATURE BASED ON RECENT SURFACE DATA AND GFS LAMP AND RAP MODEL OUTPUT...THAT CONTINUED TO SHOW HIGH TEMPERATURES THIS AFTERNOON ABOUT 5 DEGREES COLDER THAN NORMAL. DAYTIME VERTICAL MIXING WILL HELP SPEED UP WESTERLY WINDS THIS AFTERNOON WITH GUSTS OF 20 TO 25 MPH POSSIBLE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT FLURRIES ACROSS THE NW. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/... PER RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT RAP AND SREF MODEL OUTPUT...EXPECT COMBINATION OF VFR STRATOCUMULUS AND ALTOCUMULUS TO MAINTAIN BROKEN COVERAGE ACROSS THE UPPER OHIO VALLEY TODAY. ENSUING HIGH PRESSURE SUBSIDENCE WILL ENSURE NO MORE THAN CIRRUS CLOUDS TONIGHT INTO THURSDAY SO VFR WILL CONTINUE. WINDS WILL BECOME MORE WESTERLY TODAY...INCREASING TO 12 KTS BY MIDDAY. .OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
640 AM EST WED NOV 28 2012 .SYNOPSIS... MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED FOR MINOR ADJUSTMENTS FOR CLOUD COVER. LATEST HRRR SHOWS THE STRATOCU DECK CONTINUING TO ERODE FROM WEST TO THE EAST. WOULD EXPECT PARTLY SUNNY SKIES THIS MORNING ACROSS MUCH OF THE REGION. HOWEVER...WITH COLD AIR ALOFT AND 85H WINDS BACKING TO THE NW ...SCT-BKN CU SHOULD REDEVELOP THIS AFTERNOON. LATEST RAP FORECAST SOUNDINGS REINFORCE THE IDEA OF CLOUD DEVELOPMENT WITH DAYTIME HEATING. TEMPS WILL REMAIN BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT FLURRIES ACROSS THE NW. HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... CONTINUED SUBSIDENCE FROM HIGH PRESSURE WILL ALLOW MVFR CEILINGS TO BREAK THIS MORNING WITH VFR CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. WINDS WILL BECOME MORE WESTERLY TODAY...INCREASING TO 5 TO 10KTS BY LATE MORNING. .OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
613 AM CST WED NOV 28 2012 .UPDATE...FOR 12Z AVIATION DISCUSSION BELOW && .DISCUSSION.../ISSUED 328 AM CST WED NOV 28 2012/ MILD WEATHER WILL CONTINUE ACROSS THE REGION FOR THE REST OF THE WEEK. THE WARM WEATHER WILL END ON MONDAY AS THE UPPER MISSISSIPPI RIVER VALLEY WILL BE IN THE WARM SECTOR OF A DEVELOPING SURFACE LOW. THIS CYCLONE WILL DRIVE A COLD FRONT THROUGH THE REGION MONDAY NIGHT WHICH WILL BE ACCOMPANIED BY STRONG NORTHWEST WINDS AND POTENTIALLY SOME LIGHT SNOW. TODAY THROUGH FRIDAY...EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH 500MB HEIGHTS AND WINDS SHOWED NORTHWEST FLOW CENTERED ACROSS NORTH AMERICA...WITH AN UPPER LEVEL RIDGE DRAPED ALONG THE SPINE OF THE ROCKIES...AND AN IMPRESSIVE TRIO OF UPPER LEVEL LOWS IN THE GULF OF ALASKA. AT THE SURFACE A BROAD AREA OF HIGH PRESSURE SPREAD ACROSS THE NORTHERN PLAINS BENEATH THE UPPER LEVEL SUBSIDENCE ASSOCIATED ANTICYCLONIC FLOW OF THE AFOREMENTIONED UPSTREAM RIDGE. FURTHER WEST OFF THE CANADIAN COAST WERE TWO SUBSTANTIAL SURFACE LOWS WITH MSLP OF 985 AND 972 RESPECTIVELY. THESE SURFACE CYCLONES WERE A DIRECT RESULT OF UPPER LEVEL POSITIVE VORTICITY ADVECTION IN THE REGION OF LOW STATIC STABILITY CHARACTERIZED BY THE RELATIVELY WARM WATERS OF THE PACIFIC. GOING FORWARD...THE SOUTHERN MOST WAVE...WHICH IS LOCATED ROUGHLY 500MI OUT TO SEA FROM THE CALIFORNIA SHORELINE...WILL BECOME ORPHANED FROM THE POTENTIAL VORTICITY RESERVOIR TO THE NORTH...AND GRADUALLY WEAKEN AS IT CROSSES THE IDAHO ROCKIES AND REACHES THE MIDWEST THURSDAY AFTERNOON. ALTHOUGH THIS FEATURES IS RATHER BENIGN AT FIRST GLANCE...THERE IS STILL SOME UPPER LEVEL FORCING FOR ASCENT AS SEEN IN THE QVECT DIVERGENCE...DRIVEN MAINLY BY THE Q_S VECTORS ON THE DOWNSTREAM SIDE OF THE TROUGH AXIS...BUT ALSO WITH SOME CONTRIBUTION BY THE Q_N ACROSS THE TEMPERATURE GRADIENT. THIS UPWARD FORCING WILL BE ENOUGH TO INDUCE AN EAST SOUTHEASTERLY FLOW AT LOW LEVELS WHICH WILL BECOME SATURATED AND...ACCORDING TO THE FORECAST SOUNDINGS...LOOKS INCREASINGLY FAVORABLE FOR SOME FOG AND LIGHT FREEZING DRIZZLE LATE THURSDAY NIGHT INTO FRIDAY MORNING. THIS IS ALSO SUPPORTED BY LAST FEW RUNS OF THE SREF FREEZING RAIN PROBABILITIES. THE LIFT IS WEAK...AND THE SATURATION LAYER IS ONLY A FEW THOUSAND FEET THICK...SO NOT ANTICIPATING MUCH MORE THAN A FEW HUNDREDTHS OF TOTAL QPF...BUT ENOUGH TO SLICKEN UP THE UNTREATED PAVED SURFACES FOR THE FRIDAY MORNING COMMUTE. SATURDAY THROUGH WEDNESDAY...ONCE THIS WAVE MOVES EASTWARD THE UPPER LEVEL JET WILL BECOME MORE ZONAL WITH EMBEDDED SHORTWAVES EJECTING OFF FROM THE LOW IN THE GULF OF ALASKA AND PERIODICALLY TRAVERSING THE REGION LIKELY RESULTING IN NOTHING MORE THAN A FEW MID LEVEL CLOUDS. SATURDAY SHOWS A BETTER POTENTIAL FOR SOME MEASURABLE PRECIP...BUT THE THERMAL PROFILE SHOULD BE WARM ENOUGH THAT IT ALL WILL FALL AS LIQUID. LOOKING AHEAD...AFTER SEVERAL OSCILLATIONS...A STRIP OF PV WILL SWING ACROSS NEVADA ON SUNDAY AND DEVELOP A LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE ROCKIES. THE SOUTHERLY FLOW AHEAD OF THIS WAVE WILL BRING ANOTHER REINFORCEMENT OF WARM AIR WHICH WILL LAST THROUGH MONDAY. BY MONDAY NIGHT THE 28.00 ECMWF AND GFS VARY CONSIDERABLY ON THE TRACK OF THE SURFACE LOW. THE GFS TAKES IT INTO NORTHERN MINNESOTA...AND DRIVES A COLD FRONT THROUGH THE REGION. IT IS MUCH DEEPER LOW...AND THEREFORE THE COLD ADVECTION IS STRONGER WHICH IS WHY THE FORECAST SOUNDINGS SHOW LIGHT SNOW AND 30KT WINDS WITH THE POTENTIAL FOR 40KTS GUSTS ON TUESDAY. MEANWHILE THE ECMWF IS FURTHER NORTH WITH LESS SENSIBLE WEATHER ACROSS THE UPPER MIDWEST. && .AVIATION.../12Z TAF ISSUANCE/ FOREMOST AVIATION CONCERN THIS ISSUANCE IS THE TIMING OF THE IMPROVEMENT TO VFR CIGS FROM THE EXTENSIVE MVFR CONDITIONS CURRENTLY BEING OBSERVED. THE MAJORITY OF THE MODELS ARE HANDLING THE LLVL RH FIELDS QUITE POORLY...WITH THE EXCEPTION OF THE 28.06Z GFS AND 28.10Z RAP 925MB SOLUTIONS. HAVE FOLLOWED THE 925MB RH PROGS OF THE GFS/RAP FOR THE TIMING OF LOW CLOUD SCATTERING AND NORTHEAST SHIFT...WHICH WILL LIKELY NOT OCCUR UNTIL BETWEEN 17Z AND 20Z FOR MOST SITES. IT WILL HAPPEN A BIT EARLIER AT KRWF...WHICH IS SITTING ON THE SOUTHWEST PERIPHERY OF THE DECK. AFTER THE LOW CLOUDS DEPART...CIRRUS CLOUDS WILL OVERSPREAD THE AREA DURING THE REMAINDER OF TODAY AND TONIGHT. NORTHWEST WINDS WILL BACK TO THE SOUTHWEST THIS MORNING...AND THEN TO THE SOUTH BY THIS EVE. SPEEDS WILL INCREASE TO BETWEEN 7 AND 12KTS BY THIS AFTERNOON...AND THEN DECREASE TO AROUND 5 KTS THIS EVE. KMSP...AN OVERCAST CIG OF 1600 FT IS EXPECTED TO RISE TO 1800 FT BY 1630Z...BECOME BKN BY 18Z...AND THEN SCATTERED AROUND 19Z. AFTER THAT BKN-OVC CIRRUS CLOUDS WILL PREVAIL THROUGH TONIGHT. NORTHWEST WINDS WILL SHIFT TO 210 DEGREES AROUND OR SHORTLY AFTER 16Z...AND THEN BECOME SOUTHERLY DURING THE AFTERNOON. SPEEDS GENERALLY AT 4 TO 7 KTS THROUGH THE PERIOD. /OUTLOOK FOR KMSP/ THU...VFR IN THE MORNING. MVFR OR LOWER CIG AFTERNOON/OVERNIGHT. MVFR OR LOWER VIS WITH FOG/FZDZ OVERNIGHT. WINDS ENE 10 KTS. FRI...MVFR OR LOWER CIGS/VSBYS. FOG AND FZDZ POSSIBLE IN THE MORNING. WINDS E 10 KTS. SAT...MVFR OR LOWER CIGS/VSBYS POSSIBLE. CHC OF -RA/DZ. WINDS S 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JRB/LS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EST WED NOV 28 2012 .SYNOPSIS... COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY... THEN SHIFT OFFSHORE OVER THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 1020 AM WEDNESDAY... THROUGH TONIGHT: MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER. SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST... AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL... WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON. WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY OVERNIGHT LOWS OF 25 TO 30. THURSDAY AND THURSDAY NIGHT: DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER 30S ELSEWHERE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 230 AM WEDNESDAY... THE WEATHER IS EXPECTED TO REMAIN QUIET THROUGH THE SHORT TERM PERIOD AS IT CONTINUES TO BE DOMINATED BY HIGH PRESSURE. TEMPS WILL GRADUALLY MODERATE THROUGH SATURDAY AS THE CENTER OF THE SURFACE HIGH WILL BEGIN TO SLIP OFFSHORE ON FRIDAY (RESULTING IN SOUTHERLY FLOW RETURNING TO THE REGION) AND SHORTWAVE RIDGING BRIEFLY BUILDS OVER THE AREA (MOST PRONOUNCED ON SATURDAY). HIGHS ARE EXPECTED TO BE IN THE UPPER 50S TO LOW/MID 60S (WARMEST SATURDAY)...WITH OVERNIGHT LOWS GENERALLY IN THE MID 30S ON FRIDAY NIGHT BEFORE WARMING INTO THE LOWER 40S BY SATURDAY NIGHT. THERE COULD BE SOME INCREASING HIGH CLOUDS (ESPECIALLY ON SATURDAY) AHEAD OF SOME SHORT WAVE ENERGY APPROACHING FROM THE WEST. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 240 AM WEDNESDAY... MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC. TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... AS OF 1020 AM WEDNESDAY... VFR CONDITIONS WILL DOMINATE AS SURFACE HIGH PRESSURE SETTLES OVER THE AREA. SURFACE WINDS WILL VEER FROM NORTHERLY THIS MORNING TO NWLY THIS AFTERNOON...WITH WINDS BECOMING CALM TONIGHT. SEASONABLY MILD HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN THROUGH THE WEEKEND...WITH VFR CONDITIONS THROUGH SUNDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GIH NEAR TERM...DJF/CBL SHORT TERM...KRR LONG TERM...KRR AVIATION...DJF/CBL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
533 AM CST WED NOV 28 2012 .SHORT TERM...THROUGH FRIDAY NIGHT 329 AM CST WED NOV 28 2012 IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY. WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH 925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE RANGE SOUTHWEST OF I-94. PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE POTENTIAL. MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S. .LONG TERM...SATURDAY THROUGH TUESDAY 329 AM CST WED NOV 28 2012 28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI. HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO ONTARIO. && .AVIATION...TODAY AND TONIGHT 533 AM CST WED NOV 28 2012 A LARGE AREA OF STRATUS WAS LOCATED GENERALLY NORTH OF AN AUSTIN MINNESOTA TO NEILLSVILLE WISCONSIN LINE AT 11Z. SATELLITE TRENDS SHOW THE WESTERN AREAS OVER SOUTHEAST MINNESOTA MOVING SOUTHEAST. THE STRATUS HAS MOVED INTO KRST WITH IFR CEILINGS. EXPECT THESE CLOUDS TO SPREAD INTO KLSE AROUND 13Z WITH LOWER MVFR CEILINGS. 28.10Z RAP 0-0.5KM RELATIVE HUMIDITY PROG INDICATED SOUTHERN EDGE OF THE STRATUS TO MAKE IT NOT MUCH FURTHER SOUTH THAN THE INTERSTATE 90 CORRIDOR BEFORE BEGINNING TO LIFT NORTHWARD AND DISSIPATING MID TO LATE MORNING. ONCE THIS OCCURS...EXPECT VFR CONDITION FOR THE REMAINDER OF THE TAF PERIOD. && .ARX WATCHES/WARNINGS/ADVISORIES... 329 AM CST WED NOV 28 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
957 AM MST WED NOV 28 2012 .UPDATE...OVERALL...CURRENT FORECASTS SEEM ON TRACK. WAVE CLOUD CURRENTLY ACROSS MUCH OF FOOTHILLS AND URBAN CORRIDOR WHICH WRF SYNTHETIC SATELLITE IMAGERY SHOWS CONTINUING INTO THE EVENING. AS NOTED IN EARLIER DISCUSSION...THE AMOUNT OF CLOUD COULD LIMIT THE WARMUP DESPITE THE 2 DEGREE CELSIUS TEMPERATURE INCREASE AT 700 MB. MAY NEED TO SHAVE A FEW MORE DEGREES OF THE MAX TEMPS. WESTERLY FLOW ALOFT TO PREVAIL THROUGH TONIGHT...WITH WINDS A BIT GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. COULD SEE AN INCREASE THIS EVENING AS SURFACE TROUGH DEVELOPS OVER THE EASTERN PLAINS. && .AVIATION...WINDS STILL A BIT VARIABLE ACROSS AREA AIRPORTS WITH DECREASING SPEEDS. SOME HINTS OF WINDS TRYING TO GO LIGHT NORTHWEST...THOUGH SOUTHERLY DIRECTION SEEMS TO BE PREVAILING. LATEST RUC SHOWING THE DEVELOPMENT OF A WEAK ANTICYCLONE JUST NORTH OF DIA BY 18Z...WITH LIGHT NORTHEAST WINDS AT DIA AND APA AND WESTERLY AT BJC. STILL A BIT DIFFICULT TO DETERMINE IF THE SOUTHERLY GRADIENT WILL PERSIST OR ANTICYCLONE PREVAILS. FOR NOW WILL CONTINUE WITH THE CURRENT TAF TRENDS...BUT MAY NEED TO LOWER SPEEDS A BIT. && .FIRE WEATHER...FIRE DANGER WILL REMAIN ELEVATED TODAY...BUT NO FIRE WEATHER HILITES EXPECTED. GUSTY WINDS WILL AGAIN PREVAIL... MAINLY ACROSS MOUNTAINS AND NORTHERN FOOTHILLS. SHOULD BE LIGHTER THAN YESTERDAY. ALTHOUGH THE AIRMASS WILL REMAIN DRY...HUMIDITY WILL BE SLIGHTLY HIGHER THAN YESTERDAY`S READINGS. && .PREV DISCUSSION... /ISSUED 356 AM MST WED NOV 28 2012/ SHORT TERM...AN UPPER RIDGE AXIS CURRENTLY OVERHEAD WILL BE SLIGHTLY FLATTENED AND PUSHED EAST AS A VERY WEAK DISTURBANCE IN THE FLOW MOVES IN. HIGH LEVEL MOISTURE HAS REFORMED YESTERDAYS WAVE CLOUD OVER MOST OF THE FRONT RANGE AREA. LOOKING UPSTREAM AT WATER VAPOR...EXPECT THE WAVE CLOUD TO HANG ON THROUGH MOST OF THE DAY WITH INCREASING HIGH CLOUD COVER ELSEWHERE AS WELL. THIS WILL LIMIT THE HEATING WE SEE TODAY...THOUGH WITH 700 MB TEMPERATURES INCREASING BY ABOUT 2 DEGREES C...STILL EXPECT HIGHS IN THE UPPER 50S TO LOWER 60 FOR THE PLAINS AND IN THE 40S TO 50S IN THE HIGH COUNTRY. WILL HAVE TO KEEP AN EYE ON TEMPERATURES THROUGH THE DAY TO SEE IF THE CLOUDS DAMPEN THE HIGHS MORE THAN WHAT IS IN THERE. WINDS WILL REMAIN GUSTY IN THE MOUNTAINS AND HIGH FOOTHILLS...BUT EXPECTING LIGHTER SPEEDS COMPARED TO YESTERDAY. TONIGHT...A SURFACE TROUGH WILL BE DEEPENING OVER THE PLAINS TO INCREASE THE WEST WINDS COMING OUT OF THE MOUNTAINS AND FOOTHILLS. THIS ALONG WITH THE SLIGHT WARMING ALONG WILL MODERATE MINIMUM TEMPERATURES TONIGHT. LONG TERM...NOT MUCH HAS CHANGED WITH REGARD TO THE FORECAST THROUGH THIS WEEKEND. THE DEEP TROUGH IN THE EASTERN PACIFIC WILL KEEP FLAT RIDGING IN PLACE WITH GENERALLY MODERATE WEST/SOUTHWEST FLOW ALOFT ACROSS COLORADO THROUGH SUNDAY. THERE ARE STILL A COUPLE OF WEAK WAVES RIPPLING ACROSS THE STATE. THE FIRST WAVE SHOULD BRING LITTLE MORE THAN A FEW MID/HIGH CLOUDS LATE TONIGHT INTO EARLY THURSDAY. THEN ANOTHER LATE FRIDAY INTO FRIDAY NIGHT...WITH A BIT MORE MOISTURE ASSOCIATED WITH THIS ONE. AS A RESULT...HAVE ADDED JUST A SLIGHT CHANCE OF SNOW SHOWERS TO THE NORTHERN MOUNTAIN AREAS FRIDAY NIGHT. THE PASSAGE OF THIS WAVE WILL BRING ENHANCED SUBSIDENCE AND MIXING BY SATURDAY...SO INCREASED WINDS A FEW MPH FROM GOING FORECAST. SLIGHT COOLING ALOFT MAY BE OFFSET BY BETTER MIXING SO TEMPERATURES WILL LIKELY REMAIN ABOUT 15 DEGREES ABOVE NORMAL. SUNDAY IS STILL SHAPING UP TO BE THE WARMEST DAY WITH 700 MB TEMPERATURES ADVERTISED TO REACH THE 6-9C RANGE. DEPENDING ON AMOUNT OF SUNSHINE AND DOWNSLOPE...WE COULD STILL SEE HIGHS OF 70F OR MORE AND INCREASING FIRE DANGER WITH STRONGER SOUTH/ SOUTHWESTERLY FLOW DEVELOPING. BY SUNDAY NIGHT/MONDAY...A STRONGER PIECE OF ENERGY...BASICALLY LEFTOVERS OF THE EASTERN PACIFIC TROUGH...IS EXPECTED TO REACH COLORADO. Q-G VERTICAL MOTION AND MOISTURE SHOULD BE ENOUGH TO BRING AT LEAST SOME LIGHT SNOW SHOWERS TO THE MOUNTAINS. MEANWHILE...PLAINS WILL LIKELY REMAIN DRY WITH CONTINUED DOWNSLOPING FLOW. GUSTY WINDS ARE ALSO EXPECTED TO DEVELOP IN THE WAKE OF THE TROUGH PASSAGE SO BOOSTED WIND SPEEDS FOR MONDAY. TEMPERATURES WILL ALSO TURN COOLER BUT SHOULD STILL AVERAGE A FEW DEGREES ABOVE NORMAL BOTH MONDAY AND TUESDAY. AVIATION...DRAINAGE WINDS BEGINNING TO STRENGTHEN A BIT OVER KDEN AND KAPA. WINDS SHOULD DECREASE IN SPEED THROUGH THE MORNING HOURS AND BECOME LIGHT SOUTHEAST. WINDS TONIGHT WILL AGAIN BE AN ENHANCED DRAINAGE PATTERN AS A SURFACE TROUGH DEEPENS. VFR CONDITIONS THROUGH THURSDAY MORNING. FIRE WEATHER...GUSTY WINDS AND LOW HUMIDITIES ARE EXPECTED AGAIN TODAY...MAINLY OVER THE NORTHERN FOOTHILLS. HOWEVER THE WINDS WILL BE SLIGHTLY LIGHTER AND HUMIDITIES NOT AS LOW COMPARED TO YESTERDAY. FIRE DANGER WILL BE ELEVATED...BUT DO NOT EXPECT TO REACH CRITERIA VALUES FOR AN EXTENDED PERIOD SO ISSUED NO HIGHLIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....BARJENBRUCH AVIATION...D-L
AREA FORECAST DISCUSSION
NWS JACKSON KY
1248 PM EST WED NOV 28 2012 .UPDATE... ISSUED AT 1248 PM EST WED NOV 28 2012 MADE A FEW MORE TWEAKS TO THE FORECAST FOR THE REST OF TODAY. CLOUD COVER ACROSS EASTERN KENTUCKY HAS BEEN DISSIPATING ACROSS THE BOARD MUCH MORE QUICKLY THAN THE PREVIOUS FORECAST UPDATE INDICATED. IN FACT...SKIES ACROSS MOST OF THE AREA HAVE ALREADY BECOME MOSTLY CLEAR. TEMPERATURES ACROSS THE THE AREA HAVE RESPONDED IN KIND AND HAVE BEEN WARMING MORE QUICKLY...SO TODAYS HIGHS ACROSS EASTERN KENTUCKY HAVE BEEN INCREASED BY A FEW TO EVEN SEVERAL DEGREES...TO ACCOUNT FOR THE GREATER SUN EXPOSURE SO FAR TODAY. THE REST OF THE FORECAST WAS IN GOOD SHAPE. UPDATE ISSUED AT 1029 AM EST WED NOV 28 2012 MADE SOME MODIFICATIONS TO THE TEMPERATURE AND CLOUD COVER FORECAST FOR THE REST OF TODAY. THE LATEST SATELLITE IMAGERY CLEARLY SHOWS THAT CLOUD COVER HAS BEEN DISSIPATING MORE QUICKLY THIS MORNING THAN THE PREVIOUS FORECAST WAS INDICATING. THAT BEING SAID...SPED UP THE TIMING OF CLOUD DISSIPATION TODAY BY 3 OR 4 HOURS TO REFLECT THE LATEST TRENDS. WITH OUR WESTERN AND CENTRAL COUNTIES CLEARING OFF MORE QUICKLY...ALSO INCREASED TODAYS HIGH TEMPERATURES FOR MOST OF THE FORECAST AREA...TO ACCOUNT FOR THE GREATER THAN EXPECTED AMOUNT OF SUNSHINE. TODAYS HIGHS ARE NOW EXPECTED TO INCREASE INTO THE LOWER 40S ACROSS MOST OF THE AREA...WITH ONLY A FEW READINGS IN THE UPPER 30S EXPECTED IN THE HIGHER TERRAIN ALONG THE VIRGINIA BORDER. THE REST OF THE FORECAST WAS IN GOOD SHAPE. UPDATE ISSUED AT 629 AM EST WED NOV 28 2012 FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 233 AM EST WED NOV 28 2012 EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY. THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY SKIES. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 203 AM EST WED NOV 28 2012 SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS. THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND. UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN ON TUE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1248 PM EST WED NOV 28 2012 CLOUD COVER HAS BEEN DISSIPATING RATHER QUICKLY ACROSS EASTERN KENTUCKY TODAY...AND THIS TREND IS EXPECTED TO CONTINUE FOR THE REST OF THE DAY. THE TAF SITES WILL SEE VFR CONDITIONS THROUGH THE END OF THE TAF PERIOD. CLEAR SKIES AND LIGHT WINDS WILL BE ON TAP AT ALL THREE AIRPORTS THROUGH TOMORROW AFTERNOON. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...KAS LONG TERM....DUSTY AVIATION...AR
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1147 AM CST WED NOV 28 2012 .AVIATION...AFTER A DELAY THE LOW STRATUS DECK HAS BURNED OFF UNDER THE LOW ANGLE LATE NOVEMBER SUN. MORNING SOUNDING REVEALED A SHALLOW MOIST LAYER TOPPING AT 700 FEET. A BURNOFF TEMP OF 46 DEGREES VALIDATED AT LCH AND LFT. ARA WAS ANOTHER MATTER WITH THAT TEMP EXCEEDED YET IT TOOK EXTRAPOLATION OF THE CLEARING LINE TO TAKE THE HONORS AT 17Z. FIFTEEN MINUTES LATER THE LOW CLOUDS DID INDEED ERODE TO THE COAST. NOT EXPECTING A REPEAT TONIGHT AS THE RUC SHOWS CONTINUED NORTHEAST FLOW AND DRY AIR AS THE HIGH PRESSURE RIDGE DOMINATES ALTHOUGH HOW MUCH OF THE MOISTURE REMAINS IN THAT SHALLOW LAYER BELOW THE 925HPA LEVEL IS AN OPEN QUESTION. SWEENEY && .PREV DISCUSSION... /ISSUED 1023 AM CST WED NOV 28 2012/ DISCUSSION... AFTER MONITORING OBSERVATIONS OVER THE PAST HOUR AND REVIEWING ADDITIONAL MODEL DATA...IT APPEARS THE MARINE FOG IS LIKELY TO PERSIST LONGER THAT PREVIOUSLY INDICATED. OPTED TO ISSUE A MARINE DENSE FOG ADVISORY THROUGH MID AFTERNOON FOR THE COASTAL WATERS WITHIN 20 NM FROM CAMERON TO THE LOWER ATCHAFALAYA RIVER. THE OBSERVATION SITES REPORTING THE RESTRICTIONS ARE A BIT ELEVATED...SO THE VISIBILITY AT THE WATER SURFACE MAY NOT BE AS BAD AS THE OBS PORTRAY...BUT WOULD PREFER TO ERR ON THE SIDE OF CAUTION. THE INLAND FOG WORDING WAS ALSO TEMPERED DOWN TO PATCHY. 13 PREV DISCUSSION... /ISSUED 911 AM CST WED NOV 28 2012/ DISCUSSION... EARLY MORNING UPDATE ISSUED TO ADDRESS LOW STRATUS AND FOG OVER CENTRAL AND SOUTHERN LOUISIANA AND THE ADJACENT GULF WATERS. DETERMINISTIC MODEL DATA INDICATES THE INLAND STRATUS/FOG WILL ERODE PRIOR TO NOON AS THE AIRMASS UNDERNEATH THE FRONTAL INVERSION WARMS. LATEST OBS INDICATE VISIBILITY IS ALREADY STARTING TO IMPROVE HERE OVER THE COASTAL PARISHES. THE MARINE STRATUS IS LIKELY TO REMAIN UNTIL THE AFTERNOON...THOUGH I HAVE SHOWN THE VISIBILITY IMPROVING BEFORE THEN. WILL CONTINUE TO MONITOR OBS OVER THE NEXT COUPLE OF HOURS AND UPDATE AGAIN AS WARRANTED. 13 PREV DISCUSSION... /ISSUED 631 AM CST WED NOV 28 2012/ AVIATION... LOW CLOUDS AND FOG CONTINUE TO SPILL IN FROM THE NORTHEAST BEHIND THE FRONT. HAVE PUT CLOUDS IN ALL LA TAF SITES WHILE BPT SHOULD BE THE LEAST AFFECTED OF THE TAF LOCATIONS. VFR WEATHER EXPECTED AT ALL SITES BEFORE THE NOON HOUR. PREV DISCUSSION... /ISSUED 337 AM CST WED NOV 28 2012/ DISCUSSION... COOL SFC HIGH CONTINUES TO BUILD S ACROSS SE TX/LA THIS MORNING. CLOUDS WERE INITIALLY CLEARING FROM N TO S LAST EVENING. HOWEVER... VERY LOW CEILINGS AND LOWER VSBY CONTINUE TO BUILD W ACROSS C AND SC LA THIS MORNING. SINCE THIS IS A VERY THIN LOW LEVEL LAYER OF MOISTURE NEAR THE SFC...THESE LOWER CEILINGS ARE EXPECTED TO MIX OUT LATER THIS MORNING AFTER SUNRISE. EXPECTING A RATHER PLEASANT LATE FALL AFTERNOON WITH TEMPS IN THE LOWER TO MID 60S. THE SFC HIGH TO OUR NORTH WILL SLIP EAST TONIGHT...BUT ENOUGH RIDGING WILL HOLD TO PROVIDE ONE MORE COLD NIGHT...ESPECIALLY OVER C LA WHERE L&V WINDS WILL PREVAIL OVERNIGHT. CONTINUED ONGOING FORECAST OF LOWER 30S ACROSS THIS REGION...WITH THE POSSIBILITY OF A FEW LOCATIONS REACHING THE FREEZING MARK FOR AN HOUR NEAR SUNRISE. HIGHS THU SHOULD REACH THE MID/UPPER 60S. A WEAK UPPER LEVEL DISTURBANCE WILL INCREASE CLOUDS FROM THE W LATE THU INTO FRI...ALONG WITH A SLIGHT CHANCE OF SHRA ON FRI. NO FRONT ASSOCIATED WITH THIS SYSTEM...AS A SLOW MODERATION IN TEMPS WILL CONTINUE WITH POPS LESS THAN 20% EXPECTED. LOOKING INTO THE EXTENDED...THE NEXT COLD FRONT IS STILL EXPECTED TO MOVE THRU TUE/EARLY WED. THE ECMWF LOOKS A LITTLE BIT MOIST ON THIS LATEST RUN...A LITTLE MORE SO THAN THE GFS. BUMPED UP POPS FROM 20% TO 30% FOR THIS PERIOD...AND MAY HAVE TO BE RAISED SOME MORE IF THE ECMWF TRENDS CONTINUE. DML MARINE... NE WINDS TODAY WILL BECOME MORE E ON THU AS SURFACE HIGH PRESSURE ADVANCES EAST OF THE AREA. AN UPPER LEVEL DISTURBANCE EXPECTED TO MOVE ACROSS THE NORTHWEST GULF ON FRI COULD PRODUCE A FEW SHOWERS AND THUNDERSTORMS BEFORE EXITING EAST. DML && .PRELIMINARY POINT TEMPS/POPS... KLCH 64 40 67 51 71 / 0 0 10 10 20 KBPT 64 42 67 55 71 / 0 0 10 20 20 KAEX 62 33 67 44 70 / 0 0 10 10 20 KLFT 63 39 67 50 71 / 0 0 10 10 20 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM... VERMILION BAY. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1231 PM EST WED NOV 28 2012 .SYNOPSIS... A CLIPPER SYSTEM CROSSING THE GREAT LAKES COULD SPAWN A FEW FLURRIES NORTH OF I-80 THIS AFTERNOON. OTHERWISE...HIGH PRESSURE BUILDING NORTHWARD WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN UPPER LEVEL SHORTWAVE/CLIPPER SYSTEM WILL CONTINUE TO CROSS THE GREAT LAKES THIS AFTERNOON. WITH THE REINFORCEMENT OF COLD AIR EXPECT CLOUD COVER TO CONTINUE...ESPECIALLY OVER THE NORTHERN ZONES...FOR THE REMAINDER OF THE DAY. IN ADDITION...LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE DOWNWIND OF LAKE ERIE THIS AFTERNOON. A CONVERGENCE ZONE ALONG LAKE ERIE IS ALREADY SUGGESTED IN BOTH THE METARS AND CONVECTIVE CLOUD COVER OVER THE LAKE. HOWEVER...LOW LEVEL FLOW REMAINS SOUTHWESTERLY...KEEPING THE BETTER CHANCE FOR SNOW NORTH OF OUR ZONES UNTIL LATE THIS EVENING WHEN THE FLOW SHIFTS TO A MORE WEST/NORTHWEST COMPONENT. WITH THIS...WILL ONLY KEEP MOSTLY CLOUDY MENTION IN THE GRIDS FOR THE NORTHERN AND RIDGELINE COUNTIES THROUGH THE EVENING AND LEAVE ONLY A SLIGHT CHANCE OF FLURRIES IN THE EXTREME NORTHERN PORTION OF OUR CWA. ELSEWHERE...UPDATED CLOUD COVER TO DECREASE AMOUNTS THROUGH THE EVENING HOURS. WITH PLENTY OF VERTICAL MIXING AND SUNSHINE...TEMPERATURES COULD REACH A DEGREE OR TWO WARMER THAN PREVIOUSLY FORECAST. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... H8 FLOW WILL SHIFT TO THE NORTHWEST THIS EVENING AND REMAIN THERE FOR MOST OF THE NIGHT. BASED OFF OF THE MOST RECENT MODEL SOUNDINGS...THIS SHOULD KEEP SOME CLOUD COVER OVER AT LEAST POINTS NORTH OF PITTSBURGH FOR THE REMAINDER OF THE NIGHT. NAM SOUNDINGS ALSO SUGGEST ENOUGH MOISTURE IN THE DENDRITIC GROWTH ZONE FOR SNOW...ALBEIT VERY LIGHT FOR A PERIOD OVERNIGHT. DO NOT THINK IT WILL BE ENOUGH FOR ANY ACCUMULATION BUT DID KEEP SLIGHT CHANCE WORDING THROUGH MUCH OF THE NIGHT...AT LEAST UNTIL WEAK WARM ADVECTION/SUBSIDENCE TAKES OVER. FOR THE REMAINDER OF THE REGION...HIGH PRESSURE AND CLEARING SKIES SHOULD HAVE INFLUENCE ON BRINGING DOWN TEMPERATURES OVERNIGHT AND ACTUALLY WENT A DEGREE OR TWO COLDER THAN GUIDANCE AS THE BOUNDARY LAYER DECOUPLES. THURSDAY...HIGH PRESSURE WILL REMAIN THE DOMINANT PLAYER WITH WARM ADVECTION AND LOW LEVEL MIXING HELPING TO MODERATE TEMPERATURES CLOSER TO NORMAL. A WEAK BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... PER RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT RAP AND SREF MODEL OUTPUT...EXPECT COMBINATION OF VFR STRATOCUMULUS AND ALTOCUMULUS TO MAINTAIN BROKEN COVERAGE ACROSS THE UPPER OHIO VALLEY TODAY. ENSUING HIGH PRESSURE SUBSIDENCE WILL ENSURE NO MORE THAN CIRRUS CLOUDS TONIGHT INTO THURSDAY SO VFR WILL CONTINUE. WINDS WILL BECOME MORE WESTERLY TODAY...INCREASING TO 12 KTS BY MIDDAY. .OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY. THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
300 PM CST WED NOV 28 2012 .DISCUSSION... WITH AFTERNOON SUN AFTER DISSIPATION OF MORNING STRATUS TEMPS HAVE BEBOUNDED QUITE NICELY INTO THE MID 30S TO AROUND 40. HIGH PRESSURE BUILDING SE ACROSS THE CANADIAN PRAIRIES INTO N MN WILL BACKDOOR A COLD FRONT ACROSS THE AREA TONIGHT AND THURSDAY MORNING. THIS WILL BRING IN SLIGHTLY COOLER TEMPS TOMORROW ACROSS NORTHERN CWA...BUT SOUTHERN AREAS SHOULD STILL BE ABLE TO REACH AROUND 40. NOT EXPECTING ANY PCPN WITH THIS SYSTEM...BUT A FEW FLURRIES CUD BE SHAKEN OUT TO OUR NORTH. 500 MB HEIGHTS SHOWED NICE RISES LAST 24 HOURS AS TROF OVER E GREAT LAKES INTO E CANADA CONTINUES TO SLIDE EAST AND PATTERN BECOMES MORE ZONAL NEXT FEW DAYS CARRYING A FEW WEAK WAVES THRU OUR REGION. FIRST WAVE COMES THRU THE NORTHERN ROCKIES TONIGHT REACHING W MN BY 06Z FRIDAY...MOVING ACROSS OUR AREA DURING THE DAY ON FRIDAY. LOW LEVELS MOISTEN UP AHEAD OF THIS FEATURE WITH MODELS CONTINUING TO SPILT OUT LIGHT QPF. WILL CONTINUE WITH THE THEME OF PSBL FRZG DZL ACROSS AREA LATE THURSDAY NIGHT AND FRIDAY MRNG IN MOIST EASTERLY FLOW NORTH OF FRONT WHICH BY THEN WILL LIE ACROSS S IA. TEMPS ON FRIDAY WILL LIKELY BE DAMPERED BY STRATUS ACROSS AREA. SOUTHERLY FLOW INCREASES ON SATURDAY AHEAD OF NEXT WAVE BRINGING ANOTHER PUSH OF WARM AIR AND CHC -RA INTO AREA. EXPECT THAT PCPN WON`T BEGIN UNTIL AFTER SURFACE TEMPS WARM ABOVE FREEZING WITH BEST FORCING NOT DEVELOPING UNTIL LATE MORNING AND INTO THE EARLY EVENING WHEN UPPER TROF MOVES THRU. CLOUD COVER WILL AGAIN SUPPRESS MAX TEMPS WITH HIGHS REMAINING MAINLY IN THE 40S. A BIT OF A COOL PUSH BEHIND THE FRONT COMING THRU ON SATURDAY...BUT SHUD SEE SOME SUN ON SUNDAY AS NARROW RIDGE OF HIGH PRESSURE BUILDS INTO AREA. WITH SOME SUNSHINE...TEMPS SHUD WARM A FEW DEGREES SUNDAY OVER SATURDAY`S HIGHS. STRONG PACIFIC TROF PLOWS ACROSS THE DAKOTAS ON MONDAY WITH STRONG SOUTH FLOW INTO OUR REGION. A VERY MILD START TO THE DAY WITH MUCH OF THE AREA STARTING OUT THE DAY AOA 40 DEGREES. WITH SUN...COULD SEE SOME TEMPS NEAR 60 IN SC MN...BUT SOUTH WINDS BRING SLUG OF MOISTURE NORTH WHICH WILL MAKE FOR A CLOUDY DAY. WILL PLAY HIGHEST POPS WITH THIS SYSTEM IN EASTERN AREAS WHERE BEST MOISTURE TRANSPORT AND HENCE HIGHEST PWAT. COLD FRONT PLOWS INTO AREA DURING THE DAY MONDAY WHICH MAY BRING FALLING AFTERNOON TEMPS IN WESTERN AREAS. STRONG PUSH OF COLD AIR BEHIND THIS SYSTEM. GFS DRIVES COLD POCKET A BIT FARTHER S THAN ECMWF...BUT EITH SOLUTION WOULD BRING TEMPS TUESDAY/WEDNESDAY ABOUT 30 DEGREES COLDER THAN MONDAY. && .AVIATION.../18Z TAF ISSUANCE/ WITH RIDGE AXIS SHIFTING EAST THIS MORNING...SW RETURN FLOW HAS SET UP...WHICH HAS ALLOWED MORNING MVFR CIGS TO RETREAT NE WITH ONLY EAU HAVING TO DEAL WITH THEM THROUGH 19Z. THESE CIGS WILL CONTINUE NORTH UNTIL THEY RUN INTO A COLD FRONT THAT IS NOW SLIPPING THROUGH WRN NODAK AND SRN MANITOBA. THIS FRONT WILL WORK INTO THE MPX AREA LATE TONIGHT THROUGH THU MORNING...BRINGING WITH IT A GRADUAL WIND SHIFT OVER TO THE NE AND POSSIBLY ANOTHER BATCH OF IFR/MVFR CIGS. CONFIDENCE IN CIGS FOR LATE IN THE TAF PERIOD IS NOT INCREDIBLY HIGH. LOW LEVEL RH BEHIND THE COLD FRONT DOES INCREASE...WITH THE GFS/NAM CERTAINLY SHOWING THE POSSIBILITY OF LOW CIGS COMING INTO CENTRAL MN AROUND 10Z AND SAGGING DOWN TO ABOUT MSP/EAU A LITTLE AFTER 18Z. WHAT LED TO GOING WITH THE STRATUS THOUGH WAS THE SREF. PROB FOR CIGS LESS THAN 3K FT INCS TO OVER 80% WITH THE POST FRONTAL CLOUD BAND AND GIVEN THAT...DECIDED TO PUT THE CIGS IN. THIS MOISTURE IS AT 925 MB OR LOWER...SO IF WE DO SEE CIGS...THEY WOULD BE IN THE 005-015 RANGE. CONFIDENCE IN LOWER CIGS REALLY INCS AFTER 00Z FRI. KMSP...GOOD CONDITIONS EXPECTED THROUGH 18Z THU...BUT AFTER THAT...CONFIDENCE IN TAF DOES DECREASE. FOR NOW...INCLUDED SUB 017 CIGS THU AFTERNOON WITH A TIMING THAT WAS A COMPROMISE BETWEEN SREF /18Z/ AND NAM /00Z/. HRRR ALONG WITH THE RAP SHOW A NICE BAND OF LOWER CIGS DROPPING SOUTH WITH THE FRONT OVER NRN MN TONIGHT AND IF WE DO SEE THE CIGS...COULD CERTAINLY OCCUR PRIOR TO 20Z...BUT CONFIDENCE IN THE OCCURRENCE/TIMING OF THE CIGS SHOULD INCREASE TONIGHT WHEN WE GET A BETTER IDEA OF HOW THE POST FRONTAL STRATUS...IF IT IS THERE...WILL BEHAVE. /OUTLOOK FOR KMSP/ FRI...IFR/MVFR CIGS. MRNG BR/FZDZ POSSIBLE. WINDS ESE 10KTS. SAT...MVFR OR LOWER CIGS. CHANCE OF -RA. WINDS S 10 KTS. SUN...VFR. WIND S 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ BAP/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1231 PM CST WED NOV 28 2012 .UPDATE... 18Z AVIATION DISCUSSION ADDED BELOW. && .PREV DISCUSSION... /ISSUED 613 AM CST WED NOV 28 2012/ MILD WEATHER WILL CONTINUE ACROSS THE REGION FOR THE REST OF THE WEEK. THE WARM WEATHER WILL END ON MONDAY AS THE UPPER MISSISSIPPI RIVER VALLEY WILL BE IN THE WARM SECTOR OF A DEVELOPING SURFACE LOW. THIS CYCLONE WILL DRIVE A COLD FRONT THROUGH THE REGION MONDAY NIGHT WHICH WILL BE ACCOMPANIED BY STRONG NORTHWEST WINDS AND POTENTIALLY SOME LIGHT SNOW. TODAY THROUGH FRIDAY...EARLY MORNING WATER VAPOR IMAGERY TOGETHER WITH 500MB HEIGHTS AND WINDS SHOWED NORTHWEST FLOW CENTERED ACROSS NORTH AMERICA...WITH AN UPPER LEVEL RIDGE DRAPED ALONG THE SPINE OF THE ROCKIES...AND AN IMPRESSIVE TRIO OF UPPER LEVEL LOWS IN THE GULF OF ALASKA. AT THE SURFACE A BROAD AREA OF HIGH PRESSURE SPREAD ACROSS THE NORTHERN PLAINS BENEATH THE UPPER LEVEL SUBSIDENCE ASSOCIATED ANTICYCLONIC FLOW OF THE AFOREMENTIONED UPSTREAM RIDGE. FURTHER WEST OFF THE CANADIAN COAST WERE TWO SUBSTANTIAL SURFACE LOWS WITH MSLP OF 985 AND 972 RESPECTIVELY. THESE SURFACE CYCLONES WERE A DIRECT RESULT OF UPPER LEVEL POSITIVE VORTICITY ADVECTION IN THE REGION OF LOW STATIC STABILITY CHARACTERIZED BY THE RELATIVELY WARM WATERS OF THE PACIFIC. GOING FORWARD...THE SOUTHERN MOST WAVE...WHICH IS LOCATED ROUGHLY 500MI OUT TO SEA FROM THE CALIFORNIA SHORELINE...WILL BECOME ORPHANED FROM THE POTENTIAL VORTICITY RESERVOIR TO THE NORTH...AND GRADUALLY WEAKEN AS IT CROSSES THE IDAHO ROCKIES AND REACHES THE MIDWEST THURSDAY AFTERNOON. ALTHOUGH THIS FEATURES IS RATHER BENIGN AT FIRST GLANCE...THERE IS STILL SOME UPPER LEVEL FORCING FOR ASCENT AS SEEN IN THE QVECT DIVERGENCE...DRIVEN MAINLY BY THE Q_S VECTORS ON THE DOWNSTREAM SIDE OF THE TROUGH AXIS...BUT ALSO WITH SOME CONTRIBUTION BY THE Q_N ACROSS THE TEMPERATURE GRADIENT. THIS UPWARD FORCING WILL BE ENOUGH TO INDUCE AN EAST SOUTHEASTERLY FLOW AT LOW LEVELS WHICH WILL BECOME SATURATED AND...ACCORDING TO THE FORECAST SOUNDINGS...LOOKS INCREASINGLY FAVORABLE FOR SOME FOG AND LIGHT FREEZING DRIZZLE LATE THURSDAY NIGHT INTO FRIDAY MORNING. THIS IS ALSO SUPPORTED BY LAST FEW RUNS OF THE SREF FREEZING RAIN PROBABILITIES. THE LIFT IS WEAK...AND THE SATURATION LAYER IS ONLY A FEW THOUSAND FEET THICK...SO NOT ANTICIPATING MUCH MORE THAN A FEW HUNDREDTHS OF TOTAL QPF...BUT ENOUGH TO SLICKEN UP THE UNTREATED PAVED SURFACES FOR THE FRIDAY MORNING COMMUTE. SATURDAY THROUGH WEDNESDAY...ONCE THIS WAVE MOVES EASTWARD THE UPPER LEVEL JET WILL BECOME MORE ZONAL WITH EMBEDDED SHORTWAVES EJECTING OFF FROM THE LOW IN THE GULF OF ALASKA AND PERIODICALLY TRAVERSING THE REGION LIKELY RESULTING IN NOTHING MORE THAN A FEW MID LEVEL CLOUDS. SATURDAY SHOWS A BETTER POTENTIAL FOR SOME MEASURABLE PRECIP...BUT THE THERMAL PROFILE SHOULD BE WARM ENOUGH THAT IT ALL WILL FALL AS LIQUID. LOOKING AHEAD...AFTER SEVERAL OSCILLATIONS...A STRIP OF PV WILL SWING ACROSS NEVADA ON SUNDAY AND DEVELOP A LOW PRESSURE SYSTEM ON THE LEE SIDE OF THE ROCKIES. THE SOUTHERLY FLOW AHEAD OF THIS WAVE WILL BRING ANOTHER REINFORCEMENT OF WARM AIR WHICH WILL LAST THROUGH MONDAY. BY MONDAY NIGHT THE 28.00 ECMWF AND GFS VARY CONSIDERABLY ON THE TRACK OF THE SURFACE LOW. THE GFS TAKES IT INTO NORTHERN MINNESOTA...AND DRIVES A COLD FRONT THROUGH THE REGION. IT IS MUCH DEEPER LOW...AND THEREFORE THE COLD ADVECTION IS STRONGER WHICH IS WHY THE FORECAST SOUNDINGS SHOW LIGHT SNOW AND 30KT WINDS WITH THE POTENTIAL FOR 40KTS GUSTS ON TUESDAY. MEANWHILE THE ECMWF IS FURTHER NORTH WITH LESS SENSIBLE WEATHER ACROSS THE UPPER MIDWEST. && .AVIATION.../18Z TAF ISSUANCE/ WITH RIDGE AXIS SHIFTING EAST THIS MORNING...SW RETURN FLOW HAS SET UP...WHICH HAS ALLOWED MORNING MVFR CIGS TO RETREAT NE WITH ONLY EAU HAVING TO DEAL WITH THEM THROUGH 19Z. THESE CIGS WILL CONTINUE NORTH UNTIL THEY RUN INTO A COLD FRONT THAT IS NOW SLIPPING THROUGH WRN NODAK AND SRN MANITOBA. THIS FRONT WILL WORK INTO THE MPX AREA LATE TONIGHT THROUGH THU MORNING...BRINGING WITH IT A GRADUAL WIND SHIFT OVER TO THE NE AND POSSIBLY ANOTHER BATCH OF IFR/MVFR CIGS. CONFIDENCE IN CIGS FOR LATE IN THE TAF PERIOD IS NOT INCREDIBLY HIGH. LOW LEVEL RH BEHIND THE COLD FRONT DOES INCREASE...WITH THE GFS/NAM CERTAINLY SHOWING THE POSSIBILITY OF LOW CIGS COMING INTO CENTRAL MN AROUND 10Z AND SAGGING DOWN TO ABOUT MSP/EAU A LITTLE AFTER 18Z. WHAT LED TO GOING WITH THE STRATUS THOUGH WAS THE SREF. PROB FOR CIGS LESS THAN 3K FT INCS TO OVER 80% WITH THE POST FRONTAL CLOUD BAND AND GIVEN THAT...DECIDED TO PUT THE CIGS IN. THIS MOISTURE IS AT 925 MB OR LOWER...SO IF WE DO SEE CIGS...THEY WOULD BE IN THE 005-015 RANGE. CONFIDENCE IN LOWER CIGS REALLY INCS AFTER 00Z FRI. KMSP...GOOD CONDITIONS EXPECTED THROUGH 18Z THU...BUT AFTER THAT...CONFIDENCE IN TAF DOES DECREASE. FOR NOW...INCLUDED SUB 017 CIGS THU AFTERNOON WITH A TIMING THAT WAS A COMPROMISE BETWEEN SREF /18Z/ AND NAM /00Z/. HRRR ALONG WITH THE RAP SHOW A NICE BAND OF LOWER CIGS DROPPING SOUTH WITH THE FRONT OVER NRN MN TONIGHT AND IF WE DO SEE THE CIGS...COULD CERTAINLY OCCUR PRIOR TO 20Z...BUT CONFIDENCE IN THE OCCURRENCE/TIMING OF THE CIGS SHOULD INCREASE TONIGHT WHEN WE GET A BETTER IDEA OF HOW THE POST FRONTAL STRATUS...IF IT IS THERE...WILL BEHAVE. /OUTLOOK FOR KMSP/ FRI...IFR/MVFR CIGS. MRNG BR/FZDZ POSSIBLE. WINDS ESE 10KTS. SAT...MVFR OR LOWER CIGS. CHANCE OF -RA. WINDS S 10 KTS. SUN...VFR. WIND S 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JRB/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
929 AM MST WED NOV 28 2012 .SHORT TERM...VALID FOR TDY AND THU... UPDATE TO ZFP AND WRKAFP. HIGH CLOUD WAS OVER CENTRAL AND EASTERN PORTIONS OF THE REGION THIS MORNING BASED ON IR SATELLITE IMAGERY. MODELS WERE NOT HANDLING THIS CLOUD COVER WELL...AND BASED ON THE SATELLITE LOOP...THE CLOUDS OVER N WY DID NOT LOOK LIKE THEY WERE MOVING E MUCH AT ALL. AS A RESULT...HAVE LOWERED TEMPERATURES IN THE KSHR AREA. ALSO INCREASED MORNING SKY COVER CENTRAL AND E. OVER THE W...DOWNSLOPE FLOW HAD PUSHED TEMPERATURES INTO THE 40S. WITH LESS CLOUD COVER THERE...HAVE RAISED HIGHS INTO THE LOW TO MID 50S. WINDS AT KLVM AND THE STILLWATER MINE WERE GUSTY THIS MORNING...BUT BELOW ADVISORY CRITERIA. SURFACE MAP SUGGESTED PART OF THIS MAY BE GAP FLOW...BUT GRADIENT DID NOT HAVE AN IDEAL ORIENTATION. MIXING WAS LIKELY PLAYING A PART IN THE GUSTY WINDS AS WELL. HAVE INCREASED WIND SPEEDS THROUGH THE MORNING AND LEFT THE AFTERNOON ALONE AS RAP BUFKIT SHOWED SPEEDS ALOFT DECREASING THROUGH THE DAY. NEW WRF BROUGHT A SHORTWAVE AND FRONT THROUGH THE AREA ON THU WHICH WILL LIKELY BRING ISOLATED SHOWERS TO THE PLAINS. GOOD MOISTURE FETCH SETS UP INTO THE W ON FRI WHICH WILL BRING THE LIKELIHOOD OF PRECIPITATION TO THE SW MOUNTAINS. REST OF FORECAST WAS IN GOOD SHAPE. ARTHUR .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... EXTENDED MODELS CONTINUE TO REMAIN IN FAIRLY GOOD AGREEMENT THROUGH THE EXTENDED TIMEFRAME. INHERITED FORECAST REMAINS IN PRETTY GOOD SHAPE BUT DID MAKE A FEW ADJUSTMENTS WITH THIS FORECAST ISSUANCE. MILD AND WINDY PERIODS WILL PREVAIL FRIDAY INTO SUNDAY WITH MAINLY A FAST ZONAL FLOW ALOFT WITH A SERIES OF DISTURBANCES WITHIN THE FLOW MOVING ACROSS OUR FORECAST AREA. LEE- SIDE TROUGHING WILL DOMINATE FOR THE MOST PART RESULTING IN PERIODS OF WINDY CONDITIONS FOR THE LIVINGSTON AND ADJACENT FOOTHILLS LOCATIONS. THIS DOWNSLOPE FLOW ACROSS THE PLAINS WILL KEEP SHOWER CHANCES VERY LIMITED IF AT ALL WITH THE BEST CHANCES FOR PRECIP BEING SNOW SHOWERS FOR THE MOUNTAINS...ESPECIALLY THE WEST FACING SLOPES OF THE BEARTOOTH/ABSAROKA RANGES WHICH COULD SEE ABOUT 2-4 INCHES OF SNOW EVERY 12 HOURS OR SO FRIDAY AND SATURDAY. BY SUNDAY NIGHT INTO MONDAY...A STRONG DISTURBANCE AND TROUGH SWEEP ACROSS THE NORTHERN ROCKIES. MODELS BRING A STRONG SURFACE LOW ACROSS OUR FORECAST AREA ALLOWING FOR THE BULK OF PRECIP TO BE TO OUR NORTHWEST ACROSS NORTH CENTRAL MONTANA. AS THE LOW MOVES EAST IT WILL ALLOW FOR GUSTY WEST AND NORTHWEST WINDS FOR MOST OF THE PLAINS. GIVEN THIS DOWNSLOPE FLOW...WILL JUST KEEP A SLIGHT CHANCE FOR SHOWERS FOR MOST OF THE PLAINS. HOWEVER...DID RAISE POPS ACROSS OUR FAR NORTHWEST AND WEST ZONES AS THIS AREA IS CLOSE TO THE HEAVIER PRECIP. IF THE SURFACE LOW SHIFTS FURTHER NORTH OUR AREA WILL REMAIN MAINLY DRY BUT IF THE LOW SHIFTS FURTHER SOUTH A MORE SIGNIFICANT PRECIP EVENT WOULD BE LIKELY. TEMPERATURES WITH THIS SYSTEM ARE NOT THAT COLD AT ALL SO PRECIP WOULD BE A RAIN/SNOW MIX OR WET SNOW MOST LIKELY. WILL NEED TO MONITOR THIS OVER THE NEXT COUPLE OF DAYS. HOOLEY && .AVIATION... MID AND HIGH LEVEL CLOUDS WILL RESULT IN A PARTLY TO MOSTLY CLOUDY DAY ACROSS THE FORECAST AREA WITH VFR CONDITIONS PREVAILING. GUSTY SOUTHWEST WINDS WILL BE LIKELY FOR THE KLVM AREA AND THE BEARTOOTH/ABSAROKA FOOTHILLS THROUGHOUT THE DAY. HOOLEY/STC && .PRELIMINARY POINT TEMP/POPS... TDY THU FRI SAT SUN MON TUE ------------------------------------------------------- BIL 051 029/051 032/055 033/055 037/055 038/046 032/044 0/B 02/W 00/B 11/B 12/W 22/W 11/B LVM 054 031/051 040/052 037/055 038/055 037/042 028/040 0/N 22/W 12/W 22/W 23/W 43/W 21/B HDN 051 024/046 025/051 029/054 031/056 034/048 029/046 0/B 02/J 00/B 11/B 11/B 22/W 11/B MLS 042 017/041 025/050 029/052 031/053 034/043 026/040 0/B 02/J 00/B 11/B 11/B 22/W 11/B 4BQ 047 019/045 025/051 027/054 031/056 034/049 029/045 0/B 01/B 00/B 10/B 00/B 22/W 11/B BHK 046 015/036 023/046 029/048 031/052 032/041 024/035 0/B 01/B 00/B 10/B 00/B 12/W 11/B SHR 039 016/044 026/054 029/055 031/056 035/046 026/044 0/B 01/B 00/B 21/B 01/B 23/W 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
120 PM EST WED NOV 28 2012 .SYNOPSIS... COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY... THEN SHIFT OFFSHORE OVER THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 1020 AM WEDNESDAY... THROUGH TONIGHT: MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER. SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST... AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL... WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON. WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY OVERNIGHT LOWS OF 25 TO 30. THURSDAY AND THURSDAY NIGHT: DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER 30S ELSEWHERE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 120 PM WEDNESDAY... FOR FRIDAY/FRIDAY NIGHT: THE WEAKENING SURFACE HIGH SHIFTS NORTHEAST OFF THE NC COAST ON FRIDAY AND MERGES INTO A STRONG POLAR HIGH CENTERED OVER SRN QUEBEC... ALTHOUGH THE CORE OF THE COLDER AIR HOLDS WELL TO OUR NORTH OVER THE NORTHEAST STATES... AND THE CHARACTER OF THE AIR MASS OVER NC WILL CHANGE LITTLE. THE SURFACE RIDGE WILL CONTINUE TO EXTEND THROUGH CENTRAL NC... AND WHILE THE LOW LEVEL EASTERLY ONSHORE-DIRECTED FLOW WILL INCREASE OVER THE SOUTHEAST COAST... THE RIDGE ORIENTATION WILL HOLD MUCH OF THIS ATLANTIC INFLOW TO OUR SOUTH. HOWEVER... THE LIGHT WINDS AND GRADUAL INCREASE IN SURFACE DEW POINTS MAY BRING ABOUT PATCHY FOG/STRATUS LATE FRIDAY NIGHT MAINLY OVER THE SRN AND WRN CWA WHERE THE NAM/GFS/ECMWF DEPICT WEAK LOW LEVEL MOIST ISENTROPIC UPGLIDE. ALOFT... THE WEAK NEGATIVELY TILTED TROUGH LOCATED OVER NRN MEXICO THIS MORNING WILL MERGE WITH A FASTER WAVE TO THE NORTH MOVING ONTO THE WEST COAST... AND THE RESULTANT SHORTWAVE TROUGH WILL TRACK QUICKLY ACROSS THE OHIO VALLEY AND GREAT LAKES FRIDAY... MOVING OFF THE NORTHEAST COAST FRIDAY NIGHT. EXCEPT FOR THE NEAR-SURFACE LAYER... MOISTURE THROUGH THE COLUMN REMAINS QUITE LOW... ALTHOUGH FORECAST SOUNDINGS DO SUPPORT HIGH THIN CLOUDS LATE FRIDAY INTO FRIDAY NIGHT. OTHERWISE... EXPECT PLENTY OF SUNSHINE. EXPECT SLIGHTLY ABOVE NORMAL HIGHS NEAR 60 TO THE LOWER 60S. LOWS 34-38... A DEGREE OR SO UNDER STATISTICAL GUIDANCE. FOR SATURDAY/SATURDAY NIGHT: THE MID LEVEL SHORTWAVE IS EXPECTED TO MOVE EAST OFF THE NORTHEAST/MIDATLANTIC COAST IN THE MORNING... AND WILL BE FOLLOWED BY RISING HEIGHTS ALOFT OVER OUR AREA THROUGH SATURDAY NIGHT. THE SURFACE HIGH STARTS THE DAY CENTERED OVER MAINE AND MOVES EASTWARD TO OFF THE CANADIAN MARITIME COAST DURING THIS TIME... WHILE STILL EXTENDING THROUGH NC. EXPECT A STEADY MODIFICATION IN THE LOW LEVEL AIR MASS TO A MILDER AND MORE MOIST ENVIRONMENT AS SURFACE DEW POINTS CONTINUE TO RISE WITH THE LIGHT PERSISTENT EASTERLY FLOW. EXPECT SCATTERED TO BROKEN FLAT CUMULUS AS THE LOW LEVEL MOISTURE MIXES TO THE BASE OF THE SUBSIDENCE INVERSION ALOFT... BUT OTHERWISE SKIES SHOULD BE MOSTLY SUNNY. WE SHOULD SEE ANOTHER ROUND OF PATCHY FOG/STRATUS LATE SATURDAY NIGHT AREAWIDE WITH THE CONTINUED RISE IN LOW LEVEL MOISTURE... CAPPED BY NET WARMING IN THE 900-800 MB LAYER... WITH LITTLE TO NO SURFACE WIND. THE RISE IN LOW LEVEL THICKNESSES SUPPORTS HIGHS A BIT WARMER THAN FRIDAY... 61-66. MILD LOWS OF 39-45. -GIH && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 240 AM WEDNESDAY... MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC. TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 1155 AM WEDNESDAY... VFR CONDITIONS WILL PERSIST THROUGH THE 18Z VALID TAF PERIOD. WINDS AT THE SURFACE SHOULD BE LIGHT...AND EVEN THROUGH 2000FT WINDS SHOULD ONLY INCREASE TO AROUND 10KT. A VARIABLE WIND WAS FORECAST FROM TONIGHT THROUGH THURSDAY MORNING AS THE ACTUAL LOCATION OF THE CENTER OF THE HIGH WILL DETERMINE THE DIRECTION. IT IS LIKELY THAT TOWARD THE END OF THE 18Z VALID TAF PERIOD THE TRIAD SITES WILL BECOME PREDOMINANTLY SOUTHWEST...AND AT KFAY THERE COULD BE A TENDENCY FOR MOST HOURS TO SHOW SOME NORTHEAST WIND COMPONENT. SREF GUIDANCE SHOWS THAT THE CHANCES FOR MVFR CONDITIONS IN FOG ARE LOW. BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS SHOULD CONTINUE TO DOMINATE OVERALL. WINDS AT THE SURFACE AND ALOFT SHOULD BECOME BROADLY SOUTHWEST...GRADUALLY INCREASING MOISTURE OVER THE REGION. WITH THE INCREASE IN LOW-LEVEL MOISTURE...THERE WILL BE AN INCREASE IN PROBABILITIES FOR MAINLY MVFR FOG EARLY SUNDAY AND MONDAY MORNINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...DJF/CBL SHORT TERM...HARTFIELD LONG TERM...KRR AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1155 AM EST WED NOV 28 2012 .SYNOPSIS... COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY... THEN SHIFT OFFSHORE OVER THE WEEKEND. && .NEAR TERM /THROUGH THURSDAY NIGHT/... AS OF 1020 AM WEDNESDAY... THROUGH TONIGHT: MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER. SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST... AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL... WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON. WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY OVERNIGHT LOWS OF 25 TO 30. THURSDAY AND THURSDAY NIGHT: DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER 30S ELSEWHERE. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 230 AM WEDNESDAY... THE WEATHER IS EXPECTED TO REMAIN QUIET THROUGH THE SHORT TERM PERIOD AS IT CONTINUES TO BE DOMINATED BY HIGH PRESSURE. TEMPS WILL GRADUALLY MODERATE THROUGH SATURDAY AS THE CENTER OF THE SURFACE HIGH WILL BEGIN TO SLIP OFFSHORE ON FRIDAY (RESULTING IN SOUTHERLY FLOW RETURNING TO THE REGION) AND SHORTWAVE RIDGING BRIEFLY BUILDS OVER THE AREA (MOST PRONOUNCED ON SATURDAY). HIGHS ARE EXPECTED TO BE IN THE UPPER 50S TO LOW/MID 60S (WARMEST SATURDAY)...WITH OVERNIGHT LOWS GENERALLY IN THE MID 30S ON FRIDAY NIGHT BEFORE WARMING INTO THE LOWER 40S BY SATURDAY NIGHT. THERE COULD BE SOME INCREASING HIGH CLOUDS (ESPECIALLY ON SATURDAY) AHEAD OF SOME SHORT WAVE ENERGY APPROACHING FROM THE WEST. && .LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 240 AM WEDNESDAY... MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC. TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 1155 AM WEDNESDAY... VFR CONDITIONS WILL PERSIST THROUGH THE 18Z VALID TAF PERIOD. WINDS AT THE SURFACE SHOULD BE LIGHT...AND EVEN THROUGH 2000FT WINDS SHOULD ONLY INCREASE TO AROUND 10KT. A VARIABLE WIND WAS FORECAST FROM TONIGHT THROUGH THURSDAY MORNING AS THE ACTUAL LOCATION OF THE CENTER OF THE HIGH WILL DETERMINE THE DIRECTION. IT IS LIKELY THAT TOWARD THE END OF THE 18Z VALID TAF PERIOD THE TRIAD SITES WILL BECOME PREDOMINANTLY SOUTHWEST...AND AT KFAY THERE COULD BE A TENDENCY FOR MOST HOURS TO SHOW SOME NORTHEAST WIND COMPONENT. SREF GUIDANCE SHOWS THAT THE CHANCES FOR MVFR CONDITIONS IN FOG ARE LOW. BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS SHOULD CONTINUE TO DOMINATE OVERALL. WINDS AT THE SURFACE AND ALOFT SHOULD BECOME BROADLY SOUTHWEST...GRADUALLY INCREASING MOISTURE OVER THE REGION. WITH THE INCREASE IN LOW-LEVEL MOISTURE...THERE WILL BE AN INCREASE IN PROBABILITIES FOR MAINLY MVFR FOG EARLY SUNDAY AND MONDAY MORNINGS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GIH NEAR TERM...DJF/CBL SHORT TERM...KRR LONG TERM...KRR AVIATION...DJF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 AM CST WED NOV 28 2012 .SHORT TERM...THROUGH FRIDAY NIGHT 329 AM CST WED NOV 28 2012 IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY. WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH 925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE RANGE SOUTHWEST OF I-94. PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE POTENTIAL. MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S. .LONG TERM...SATURDAY THROUGH TUESDAY 329 AM CST WED NOV 28 2012 28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI. HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO ONTARIO. && .AVIATION...THROUGH 18Z THURSDAY 1142 AM CST WED NOV 28 2012 MORNING IFR CLOUDS ARE BEGINNING TO ERODE AS SURFACE WINDS TURN TO THE SOUTHWEST ALONG WITH 925 MB WARMING...HELPING TO MIX OUT THE SHALLOW CLOUD LAYER. THIS PROCESS WILL TAKE ANOTHER HOUR AT KLSE...AS A PATCH OF CLOUDS REMAINS NEAR THE TERMINAL. THE CLEARING WILL GIVE WAY TO VFR CONDITIONS FOR THE REMAINDER OF THE PERIOD...WITH THE PREDOMINANT FLOW OUT OF THE SOUTH/SOUTHWEST. SCATTERED TO BROKEN CIRRUS IS EXPECTED TO MOVE OVER THE REGION THIS AFTERNOON THROUGH THE OVERNIGHT...THEN EXIT EAST BY EARLY THURSDAY MORNING. SOME FORECAST MODELS SUGGEST AS THESE CLOUDS EXIT AND ALONG WITH LIGHT SURFACE WINDS...SOME PATCHY FOG IS POSSIBLE BEGINNING 10Z THROUGH 15Z. THIS CONCERN IS MORE FOR KRST...AND FOR NOW HAVE INCLUDED A MENTION OF LIGHT FOG/MIST BUT NO RESTRICTIONS. && .ARX WATCHES/WARNINGS/ADVISORIES... 329 AM CST WED NOV 28 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...ZT