Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/24/12


AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
652 PM EST FRI NOV 23 2012 .UPDATE... CLEAR SKIES PREVAIL THIS EVENING ACROSS THE REGION...WITH A DRY COLD FRONT APPROACHING FROM CENTRAL GA. ABOUT A 100 MILE STRETCH OF MID DECK CLOUDS ARE ASSOCIATED WITH THE FRONT. THESE CLOUDS WILL ENTER INTERIOR SECTIONS OF SE GA BY LATE THIS EVENING...MOVING SOUTH INTO NE FL OVERNIGHT. ALTHOUGH THE FRONT WILL MOVE INTO A DRIER AIRMASS STILL THINK SOME CLOUDS WILL REMAIN...THUS HAVE INCREASED SKY COVER ACROSS SE GA INTO NE FL...WITH PARTLY TO MOSTLY CLOUDY SKIES LATER TONIGHT. THESE CLOUDS WILL LIKELY PUT A CAP ON THE TEMPERATURE FALL WITH LOWS ONLY FALLING INTO THE MID/UPPER 40S FOR MOST OF NE FL WITH A LITTLE COOLER READINGS FOR SE GA AS THE CLOUDS WILL EXIT BY LATER IN THE OVERNIGHT. && .AVIATION... A DRY COLD FRONT TRAILED BY CEILINGS OF 3-6 KFT WAS PROGRESSING SOUTHWARD OVER N GA THIS EVENING. THE RAP SHORT TERM GUIDANCE AND MOS STATISTICS SUGGESTED THAT THIS BAND OF STRATUS WOULD COMPLETELY EVAPORATE BEFORE REACHING THE ALTAMAHA RIVER BASIN...BUT BASED ON EVENING SATELLITE TRENDS THERE WAS LITTLE SIGN OF THIS LOW LEVEL MOISTURE THINNING SIGNIFICANTLY. FOR THE 00Z TAF PACKAGE INTRODUCED A BROKEN 3KFT AT SSI BETWEEN 04-08Z BASED ON THE DECKS RECENT SPEED OF ADVANCEMENT SOUTHWARD. ALSO INTRODUCED BROKEN CEILINGS OF 5 KFT AROUND 07Z AT JAX...CRG AND VQQ. IF THE STRATUS CONTINUES TO SHOW SIGNS OF HOLDING TOGETHER FOR THE NEXT SEVERAL HOURS AFTER SUNSET...WILL AMENDED THE NE FL TAFS TO INCLUDED TEMPO MVFR CIGS EARLY SAT MORNING. VFR CONDITIONS WILL DEVELOP FROM NW TO SE SAT MORNING AS MUCH DRIER AND COLDER POST-FRONTAL AIR MIXES DOWN WITH WNW WINDS 10-15 KT AND GUSTS 15-20 KT POSSIBLE. && .MARINE... SCA SEAS CONTINUE AT BUOY 41012...THUS WILL CONTINUE SCA FOR SEAS OFFSHORE THROUGH EARLY SUNDAY MORNING...AS EASTERLY SWELLS ARE EXPECTED TO PERSIST. GENTLE TO MODERATE NORTHWEST WINDS THIS EVENING WILL BECOME WEST TO NORTHWESTERLY AND INCREASE TO 15 TO 20 KNOTS OVERNIGHT AS A DRY COLD FRONT MOVES THROUGH. HIGH PRESSURE WILL THEN BUILD INTO OUR REGION SATURDAY THROUGH SUNDAY NIGHT. EXPECT WINDS TO VEER TO SOUTHERLY BY MONDAY NIGHT AND TUESDAY AS THE NEXT COLD FRONT APPROACHES. RIP CURRENTS: HIGH RISK THROUGH TONIGHT AT THE NORTHEAST FL BEACHES WITH MODERATE RISK FOR SE GA BEACHES. A MODERATE TO HIGH RISK OF RIP CURRENTS IS ANTICIPATED ON SATURDAY FOR NORTHEAST FLORIDA AS EASTERLY SWELLS WILL BE SLOW TO SUBSIDE. && .FIRE WEATHER... NORTHWESTERLY WINDS WILL INCREASE TO 10-15 MPH BY LATE SATURDAY MORNING IN THE WAKE OF A DRY COLD FRONTAL PASSAGE. WILL CONTINUE THE FIRE WEATHER WATCH FOR NE FL SATURDAY FOR HIGH DISPERSION VALUES AND CRITICALLY LOW RH. ALTHOUGH WINDS WILL DECREASE AS HIGH PRESSURE BUILDS INTO OUR AREA ON SUNDAY...LONG DURATIONS OF CRITICALLY LOW RELATIVE HUMIDITY VALUES ALONG WITH ERC VALUES CLIMBING TO NEAR 35 UNITS MAY BRING RED FLAG CONDITIONS TO INTERIOR LOCATIONS OF NORTHEAST FLORIDA DURING THE AFTERNOON HOURS. RELATIVE HUMIDITY VALUES SHOULD THEN SLOWLY RECOVER BY MONDAY AFTERNOON AS HIGH PRESSURE SHIFTS EAST OF THE REGION AHEAD OF AN APPROACHING COLD FRONT. && .PRELIMINARY POINT TEMPS/POPS... AMG 41 61 29 64 / 0 0 0 0 SSI 50 63 40 64 / 0 0 0 0 JAX 47 65 32 65 / 0 0 0 0 SGJ 50 66 38 62 / 0 0 0 0 GNV 45 66 31 66 / 0 0 0 0 OCF 45 68 32 68 / 0 0 0 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL-GILCHRIST- HAMILTON-MARION-NASSAU-PUTNAM-SUWANNEE-UNION. HIGH RIP CURRENT RISK UNTIL 5 AM EST SATURDAY FOR DUVAL-FLAGLER- NASSAU-ST JOHNS. FIRE WEATHER WATCH FROM SATURDAY MORNING THROUGH SATURDAY AFTERNOON FOR ALACHUA-BAKER-BRADFORD-CLAY-COLUMBIA-DUVAL- FLAGLER-GILCHRIST-HAMILTON-MARION-NASSAU-PUTNAM-ST JOHNS- SUWANNEE-UNION. GA...FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING FOR APPLING-ATKINSON-BACON-BRANTLEY-CHARLTON-CLINCH-COFFEE- ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-WARE- WAYNE. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EST SUNDAY FOR ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE. && $$ ALLEN/ENYEDI/LETRO
AREA FORECAST DISCUSSION
NWS DES MOINES IA
328 AM CST THU NOV 22 2012 .SHORT TERM /TODAY/... MAIN CONCERN TODAY WILL BE THE WIND FOLLOWING THE FRONT BETWEEN MID TO LATE AFTERNOON HOURS ACROSS THE NORTH. GUIDANCE AND BUFR SOUNDINGS STILL SUGGEST SUSTAINED WINDS NEAR 30 MPH IN THE ADVISORY AREA WITH GUSTS TO NEAR 40 TO 45 MPH BY MID AFTERNOON. THE PEAK CONDITIONS ARE ONLY EXPECTED TO LAST ABOUT 2 TO 3 HOURS BETWEEN 2 AND 5 PM AND AS SUN SETS...EXPECT THAT WIND GUSTS WILL DROP OFF RATHER QUICKLY. ANOTHER WARM DAY IS EXPECTED FOR THANKSGIVING WITH SOUTH WINDS AHEAD OF THE ADVANCING COLD FRONT. HIGHS WILL REACH THE 60S OVER MUCH OF THE SOUTHEAST WHILE THE NORTHWEST WILL BEGIN TO SEE HIGHS RETREATING INTO THE 50S FOR THE DAY. BY 12Z FRONT WILL REACH FAR NW CORNER WITH FRONT NEARLY BISECTING THE REGION BY 18Z. FRONT WILL BE THROUGH THE REGION BY LATE AFTERNOON WITH FALLING TEMPERATURES BEHIND THE SYSTEM. MOISTURE IS STILL LACKING WITH THE SYSTEM AND WILL CONTINUE ONLY SLIGHT CHANCES FOR RAIN IN THE FAR SOUTHEAST FOR EARLY AFTERNOON HOURS. REMAINDER OF THE AREA WILL BE RAIN FREE. .LONG TERM /TONIGHT THROUGH WEDNESDAY/... MAIN FORECAST CONCERN FOR BEGINNING OF EXTENDED WILL BE WINDS TONIGHT AND TEMPERATURES. FRONT WILL CONTINUE TO PUSH ACROSS THE FAR SE OF CWA OVERNIGHT TONIGHT...WITH MUCH COLDER TEMPERATURES AND STRONG WINDS BEHIND THE FRONT. HAVE KEPT WINDS UP OVERNIGHT WITH STRONG PUSH OF SUBSIDENCE BEHIND FRONT AND CAA. WITH STRONG WINDS WILL KEEP WIND ADVISORY THROUGH THE OVERNIGHT HOURS ACROSS THE NORTH. AS LOW PULLS EASTWARD...WINDS WILL RELAX A BIT FOR FRIDAY AFTERNOON...BUT COLD CANADIAN AIR WILL CONTINUE TO STREAM OVER REGION...WITH HIGHS SLIGHTLY BELOW NORMAL. BROAD UPPER LEVEL RIDGE WILL REMAIN OVER PLAINS FOR THE WEEKEND...WITH SURFACE HIGH PRESSURE PUSHING SE. HAVE DROPPED TEMPERATURES A FEW DEGREES FRIDAY NIGHT AS CONDITIONS LOOK RIGHT FOR A GOOD RADIATIONAL COOLING NIGHT WITH LIGHT WINDS AND CLEAR SKIES AND CENTER OF HIGH PASSING WEST OF CWA. WAA WILL THEN SET IN FOR SATURDAY AND SUNDAY AND SOUTHERLY FLOW WILL RETURN WITH TEMPERATURES WARMING SLIGHTLY FOR THE END OF THE WEEKEND AHEAD OF ANOTHER FRONTAL BOUNDARY. ANOTHER WEEK FRONTAL BOUNDARY WILL PUSH SOUTH ACROSS IOWA FOR LATE SUNDAY...WITH LIMITED MOISTURE...HAVE OPTED TO KEEP CONDITIONS DRY FOR SUNDAY AND SUNDAY NIGHT...THOUGH CANNOT RULE OUT LIGHT RAIN...DO NOT HAVE ENOUGH CONFIDENCE TO INCLUDE MENTION ATTM. SYSTEM BECOME MUDDLED WITH LITTLE MODEL AGREEMENT. ECMWF CONTINUES TO PUSH FRONT SOUTH...WITH GEM AND GFS PULLING AN AREA OF LOW PRESSURE NE ACROSS THE AREA. HAVE CONTINUED TO TREND TOWARD THE WETTER GEM/GFS SOLUTION WITH ECMWF/S DRY SOLUTION STILL AN OUTLIER. SYSTEM WILL QUICKLY PULL EASTWARD WITH PRECIP CHANCES ENDING BY TUESDAY NIGHT. WITH COOLER TEMPERATURES BEHIND FRONT COULD SEE RAIN/SNOW MIX CHANGING OVER TO SNOW MONDAY NIGHT INTO TUESDAY. HOWEVER ACCUMULATIONS LOOK TO BE MINIMAL ATTM. AS UPPER LEVEL NORTHWEST FLOW RETURNS FOR REMAINDER OF THE PERIOD...ANOTHER FAST MOVING SYSTEM IS EXPECTED TO PUSH ACROSS IOWA FOR LATE IN THE PERIOD. HOWEVER...HAVE OPTED TO KEEP CONDITIONS DRY FOR NOW GIVEN DIFFICULTY IN TIMING SUCH QUICK SYSTEM SO FAR OUT. && .AVIATION...22/06Z PRIMARY CONCERN REMAINS WINDS THROUGH THE PERIOD. SFC WINDS WILL REMAIN STEADY FROM THE SOUTH TONIGHT...BUT EXPECT LLWS TO PERSIST AT KDSM/KALO/KOTM WITH LATEST RAP STILL SHOWING 500M AGL WINDS /1600 FT/ AROUND 50KTS. HAVE REMOVED LLWS AT KFOD/KMCW HOWEVER WHERE WINDS ARE ALREADY GUSTING INTO THE 20S. LLWS SHOULD END BY MORNING WITH COLD FRONT REACHING NWRN IA BY 12Z. WINDS WILL THEN BECOME GUSTY BEHIND MIDDAY AND AFTERNOON COLD FRONTAL PASSAGE...GENERALLY 25-30KTS BUT A FEW PERIODS OF HIGHER GUSTS ARE ALSO POSSIBLE. GUSTY WINDS WILL CONTINUE BEYOND THE VALID PERIOD AND MAY EVEN BE STRONGER THU NIGHT INTO EARLY FRI. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM NOON TODAY TO 6 AM CST FRIDAY FOR CALHOUN- CERRO GORDO-EMMET-HANCOCK-HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS- SAC-WEBSTER-WINNEBAGO-WORTH-WRIGHT. && $$ SHORT TERM...REV LONG TERM...AWB AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1127 PM CST WED NOV 21 2012 .SHORT TERM /TONIGHT/... FAIRLY TIGHT PRESSURE GRADIENT WILL CONTINUE TO PROVIDE GUSTY SOUTH WINDS THROUGH THE OVERNIGHT HOURS AS A SURFACE LOW AND COLD FRONT APPROACH THE STATE. THE SURFACE LOW LOOKS TO BE CENTERED OVER NORTHERN MN BY AROUND 12Z AND COLD FRONT WILL BE CLOSE TO WESTERN IOWA. WENT AT OR SLIGHTLY ABOVE GUIDANCE FOR OVERNIGHT LOWS TONIGHT...NAM BEING THE COLDEST COMPARED TO THE ECMWF/GFS. .LONG TERM /THURSDAY THROUGH WEDNESDAY/... THURSDAY WILL BEGIN QUITE MILD WHICH WILL CONTINUE THROUGH NOON. A SHORT WAVE LIFTING THROUGH THE WEAKENING SOUTHWEST FLOW COULD BRING A FEW CLOUDS AND LIGHTS SHOWERS TO THE SOUTHEAST WHICH COULD TEMPER TEMPERATURES A BIT. A COLD FRONT WILL ENTER THE NORTHWEST AREA BY LATE MORNING THEN MOVE ACROSS THE REMAINDER OF CENTRAL IOWA THE REMAINDER OF THE DAY. TEMPERATURES WILL BE STEADY OR SLIGHTLY RISING WITH THE INITIAL FROPA DUE TO INCREASED MIXING BEFORE FALLING. THE MIXING WILL ALSO INCREASE THE WINDS THROUGH THE AFTERNOON. THE COLD ADVECTION WILL PROMOTE EFFICIENT MOMENTUM TRANSFER OF MIXED LAYER WINDS TO THE SURFACE. THIS WILL PUSH WINDS TO WIND ADVISORY CRITERIA OVER NORTHERN IOWA BY MID THURSDAY AFTERNOON. THE WINDS WILL DIMINISH A BIT INTO THE EVENING BEFORE ANOTHER SURGE OF COLD ADVECTION DROPS SOUTH OUT OF MINNESOTA LATE EVENING AND THROUGH THE REMAINDER OF THE NIGHT. THIS SURGE OF COLD ADVECTION WILL INCREASE LOW LEVEL MIXING ONCE AGAIN THOUGH MIXED LAYER WINDS WILL BE HIGHER THAN THE AFTERNOON. SHOULD REACH WIND ADVISORY CRITERIA AGAIN ESPECIALLY OVER NORTHERN IOWA. HAVE ISSUED A WIND ADVISORY FOR PORTIONS OF THE NORTH FOR THURSDAY AFTERNOON AND NIGHT TO COVER THESE EVENTS WHICH WILL IMPACT HOLIDAY TRAVEL. FRIDAY WILL BE A COLD AND BLUSTERY DAY WITH BREEZY NORTHWEST WINDS AND TEMPERATURES IN THE 30S. HIGH PRESSURE WILL SETTLE IN FRIDAY NIGHT WITH TEMPERATURES FALLING INTO THE TEENS MOST AREAS. SOUTHERLY WINDS WILL DEVELOP ON SATURDAY HOWEVER A STEEP LOW LEVEL INVERSION AND MID LEVEL THETA-E ADVECTION INDUCED CLOUDS WILL LIMIT MODERATION POTENTIAL. SUNDAY WILL BE WARMER AND CLOSER TO CLIMATOLOGY. A SHORT WAVE DROPPING THROUGH THE NORTHWEST FLOW EARLY NEXT WEEK WILL DRIVE A LONG WAVE TROUGH INTO THE REGION ALONG WITH ANOTHER COLD FRONT PUSHING TEMPERATURES BACK INTO THE 30S. THE PRIMARY PRECIPITATION EVENT AND LOW PRESSURE SYSTEM SHOULD TRACK SOUTHEAST OF IOWA AND INTO THE OHIO VALLEY. LIGHT RAIN OR SNOW IS POSSIBLE BUT LITTLE TO NO ACCUMULATION OF THE WHITE STUFF IS EXPECTED. && .AVIATION...22/06Z PRIMARY CONCERN REMAINS WINDS THROUGH THE PERIOD. SFC WINDS WILL REMAIN STEADY FROM THE SOUTH TONIGHT...BUT EXPECT LLWS TO PERSIST AT KDSM/KALO/KOTM WITH LATEST RAP STILL SHOWING 500M AGL WINDS /1600 FT/ AROUND 50KTS. HAVE REMOVED LLWS AT KFOD/KMCW HOWEVER WHERE WINDS ARE ALREADY GUSTING INTO THE 20S. LLWS SHOULD END BY MORNING WITH COLD FRONT REACHING NWRN IA BY 12Z. WINDS WILL THEN BECOME GUSTY BEHIND MIDDAY AND AFTERNOON COLD FRONTAL PASSAGE...GENERALLY 25-30KTS BUT A FEW PERIODS OF HIGHER GUSTS ARE ALSO POSSIBLE. GUSTY WINDS WILL CONTINUE BEYOND THE VALID PERIOD AND MAY EVEN BE STRONGER THU NIGHT INTO EARLY FRI. && .DMX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY THURSDAY AFTERNOON THROUGH THURSDAY NIGHT EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-SAC-CALHOUN-WEBSTER && $$ SHORT TERM...PODRAZIK LONG TERM...DONAVON AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
950 AM MST THU NOV 22 2012 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 226 AM MST THU NOV 22 2012 MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST. AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET... CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH OTHER AND REALITY. TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND UNITED STATES BORDER. SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z. SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3 HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY CRITERIA WITH THE NORTH THE CLOSEST. HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT. MADE ONLY SLIGHT ADJUSTMENTS. GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE SLOWER. SO WARMED UP THE MINS. FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES COULD FALL RAPIDLY BEFORE THIS GETS GOING. SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP MAXES SOME AT THIS TIME. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1142 PM MST WED NOV 21 2012 SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY TUESDAY WITH NO PRECIPITATION CHANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 948 AM MST THU NOV 22 2012 VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS AT KGLD AND KMCK. GUSTY NORTH WIND WILL GRADUALLY DECREASE BY SUNSET AND OVERNIGHT INTO FRIDAY MORNING AS HIGH PRESSURE BUILDS INTO THE REGION BEHIND THE COLD FRONT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...024 AVIATION...032
AREA FORECAST DISCUSSION
NWS GOODLAND KS
418 AM MST THU NOV 22 2012 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 226 AM MST THU NOV 22 2012 MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST. AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET... CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH OTHER AND REALITY. TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND UNITED STATES BORDER. SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z. SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3 HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY CRITERIA WITH THE NORTH THE CLOSEST. HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT. MADE ONLY SLIGHT ADJUSTMENTS. GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE SLOWER. SO WARMED UP THE MINS. FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES COULD FALL RAPIDLY BEFORE THIS GETS GOING. SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP MAXES SOME AT THIS TIME. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1142 PM MST WED NOV 21 2012 SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY TUESDAY WITH NO PRECIPITATION CHANCES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 415 AM MST THU NOV 22 2012 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COLD FRONT WILL MOVE THROUGH THE AREA THIS MORNING. AS IT DOES SO...WINDS WILL INCREASE THROUGH THE MORNING AND BECOME GUSTY. SOME BLOWING DUST COULD OCCUR BUT DO NOT EXPECT TO BE WIDESPREAD ENOUGH OR TO CREATE SUB VFR CONDITIONS AT THIS TIME. WINDS ARE NOT EXPECTED TO DECREASE UNTIL LATE IN THE AFTERNOON AND THEN REMAIN LIGHT THROUGH THE REST OF THE NIGHT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...024 AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 AM MST THU NOV 22 2012 .SHORT TERM...(TODAY THROUGH SATURDAY NIGHT) ISSUED AT 226 AM MST THU NOV 22 2012 MAIN FORECAST ISSUE WILL BE THE WINDS TODAY WITH MINOR CONCERNS OF HOW MUCH IT COOLS OFF THROUGH TOMORROW AND HOW MUCH THE WARM UP IS ON SATURDAY. SATELLITE SHOWING AN AMPLIFIED PATTERN OVER THE PACIFIC WITH A LESS AMPLIFIED MORE PROGRESSIVE FLOW FROM NORTH AMERICA INTO THE ATLANTIC. COLD FRONT IS APPROACHING THE AREA FROM THE NORTHWEST. AT JET LEVEL...THE ECMWF WAS DOING A LITTLE BETTER THAN THE UKMET... CANADIAN...AND NAM ON THE JET SEGMENT ASSOCIATED WITH THE NORTHERN STREAM SYSTEM. THE GFS FOLLOWED BY THE SREF WAS TOO STRONG WITH THE JET BEHIND THE INCOMING TROUGH. AT MID LEVELS THE MODELS INITIALIZED FINE WITH NO BIG PROBLEMS. THE RUC AND NAM WERE DOING BEST ON THE WIND/PRESSURE FIELD. LOW LEVEL THERMAL GUIDANCE WAS CLOSE TO EACH OTHER AND REALITY. TODAY/TONIGHT...SATELLITE AND UPPER AIR IS SHOWING A VERY DRY AND SUBSIDENT AIR MASS BEHIND THE SYSTEM MOVING ALONG THE CANADIAN AND UNITED STATES BORDER. SURFACE TO 850 MB WINDS ARE HIGHEST AT 12Z AND THEN DECREASE BY 18Z. SOME PLACES COULD REACH 35 KNOT GUSTS. HIGHEST OBSERVED 3 HOUR PRESSURE RISES HAVE OCCURRED MUCH FURTHER NORTH AND ARE NOT ANYTHING OUT OF THE ORDINARY AT THIS TIME. FORECAST PRESSURE GRADIENT AND 3 HOUR PRESSURE RISES ARE HIGHEST EARLY ON AND DECREASE BY 18Z. IN FACT BOTH WOULD INDICATE A QUICK BURST OF THE STRONGEST WINDS RIGHT AFTER THE FROPA AND SUPPORT WINDY CONDITIONS BUT NOT QUITE AT ADVISORY CRITERIA. STRONGEST SUBSIDENCE LOOKS TO BE NEAR THE NORTHERN PORTION OF OUR AREA. THAT AND OTHER GUIDANCE WOULD SUPPORT THE HIGHEST WINDS TO BE IN THE NORTHERN PORTION OF THE AREA AND MAYBE SOME OF THE SOUTHWEST. SO HAVE CONTINUE TO HAVE WINDS JUST UNDER ADVISORY CRITERIA WITH THE NORTH THE CLOSEST. HIGH LEVEL CLOUDS WILL BE THICKEST EARLY DUE TO THE RIGHT REAR QUADRANT OF THE MID AND UPPER JET BEING CLOSE. OVERNIGHT TEMPERATURES HAVE BEEN ALL OVER THE PLACE AS THE PREFRONTAL TROUGH WORKS ITS WAY ACROSS. FRONT LOOKS TO PUSH THROUGH THE AREA EARLY TODAY. NWP IS WARMER THAN IT WAS YESTERDAY AND IN CLOSE AGREEMENT. MADE ONLY SLIGHT ADJUSTMENTS. GUIDANCE THIS MORNING KEEPS THE WINDS STRONGER FOR TONIGHT THAN THE IT DID YESTERDAY DUE TO THE SURFACE RIDGE MOVING IN A LITTLE SLOWER. SO WARMED UP THE MINS. FRIDAY/FRIDAY NIGHT...SHOULD SEE PLENTY OF SUN WITH AREA COMING UNDER THE CONTROL OF RIDGING/SUBSIDENCE/DRYING. SURFACE HIGH MOVES ACROSS DURING THE DAY AND IS NOT TOO FAR EAST OF THE AREA BY LATE IN THE AFTERNOON. NEW GUIDANCE IS CLOSE TO EACH OTHER AND NOT TOO DIFFERENT FROM ONGOING FORECAST SO MADE LITTLE IF ANY CHANGES. WIND FIELD STARTS OUT LIGHT BEFORE WAA AND DOWNSLOPE STARTS. TEMPERATURES COULD FALL RAPIDLY BEFORE THIS GETS GOING. SATURDAY/SATURDAY NIGHT...AGAIN LOOKS LIKE A LOT OF SUN THROUGH THE DAY. WINDS STAY LIGHT THROUGH THE DAY BUT MOSTLY FROM A DOWNSLOPE DIRECTION. NEWER GUIDANCE IS PRETTY CLOSE TO EACH OTHER AND WARMER THAN CURRENT FORECAST. CONSIDERING THE DEEP/INCREASING WESTERLY FLOW ALOFT THIS DOES MAKE SENSE. DRY AIR MASS AND DRY GROUND SHOULD ALLOW A QUICK RESPONSE TO THE EVEN LIGHT DOWNSLOPE WIND. HOWEVER MAY HAVE SOME WAVE CLOUDS DEVELOP EVEN THOUGH MODELS SAY NO. WILL WARM UP MAXES SOME AT THIS TIME. .LONG TERM...(SUNDAY THROUGH WEDNESDAY) ISSUED AT 1142 PM MST WED NOV 21 2012 SHORTWAVE TROUGH WILL MOVE FROM THE NORTHERN ROCKIES TO THE CENTRAL PLAINS SUNDAY NIGHT AND MONDAY. MODEL SOLUTIONS CONTINUE TO RETREAT FROM PRECIPITATION CHANCES...AND ITS LOOKING LIKE LITTLE TO NONE IN THE LOCAL AREA. COLDER AIR WILL MOVE IN BEHIND THE COLD FRONT SUNDAY NIGHT BUT COOL DOWN WILL BE SHORT LIVED. UPPER RIDGE WILL QUICKLY REBUILD OVER THE GREAT BASIN EARLY IN THE WEEK THEN ROCKIES BY MID WEEK. TEMPERATURES WILL RETURN TO ABOVE NORMAL BY TUESDAY WITH NO PRECIPITATION CHANCES. && .AVIATION...FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1026 PM MST WED NOV 21 2012 VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS. THE ONLY CLOUD COVER WILL BE SOME CIRRUS MOVING THROUGH THIS MORNING FROM THE WEST. OF BIGGER CONCERN FOR AVIATION WILL BE THE WINDS THIS AFTERNOON. A COLD FRONT AND LEE TROUGH WILL PUSH THROUGH DURING THE FORECAST PERIOD. A TIGHT PRESSURE GRADIENT AND STRONGER WINDS ALOFT WILL ALLOW FOR GUSTY NORTH WINDS AT THE SURFACE. WINDS WILL GRADUALLY PICK UP IN THE MORNING HOURS AND WINDS FOR THE AFTERNOON HOURS LOOK TO BE SUSTAINED AT AROUND 25 KTS WITH GUSTS TO 35 SUGGESTED BY GUIDANCE. WINDS WILL WEAKEN BY THIS EVENING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...024 AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1100 PM CST WED NOV 21 2012 ...UPDATE TO AVIATION FOR 06Z TAFS... .SYNOPSIS... ISSUED AT 1023 PM CST WED NOV 21 2012 THE 22.00Z 250 HPA MAP SHOWED A 100 KT NORTHWESTERLY JET ACROSS THE PACIFIC NORTHWEST ON THE UPSTREAM SIDE OF A LONGWAVE TROF LOCATED ACROSS THE NORTHERN ROCKIES. ANOTHER JET STREAK OF AROUND 110 KT WAS FOUND ON THE BASE OF A VERY AMPLIFIED TROF LOCATED ACROSS FLORIDA AND THE SW ATLANTIC BASIN. A VERY SUBTLE WIND MAX AROUND 50 KT WAS ALSO OBSERVED AT KDDC (DODGE CITY, KS). AT 500 HPA, VERY COLD MID LEVEL TEMPS OF -30 DEG C TO -35 DEG C WERE OBSERVED ACROSS THE PACIFIC NORTHWEST. CLOSER TO HOME, SOME MID LEVEL MOISTURE WAS NOTED ACROSS WEST TEXAS AHEAD OF A WEAK PRESSURE PERTURBATION. DRY AIR ADVECTION WAS NOTED ACROSS THE DEEP SOUTH IN THE WAKE OF THE AFOREMENTIONED UL DISTURBANCE. AT 700 HPA, TEMPS WERE WARM ACROSS THE CENTRAL PLAINS FOR NOVEMBER STANDARDS WITH MANY LOCATIONS REPORTING IN THE 5 DEG C TO 8 DEG C RANGE. THE ATMOSPHERE WAS FAIRLY DRY IN THIS AREA AS WELL. 850 HPA TEMPS ACROSS THE PLAINS WERE WARM WITH A DRY/ADIABATICALLY MIXED PROFILE ACROSS KANSAS. TEMPS AROUND 15 DEG C TO 17 DEG C WERE COMMON FROM WEST TEXAS TO MINNESOTA. AT THE SFC, TWO FRONTAL SYSTEMS WERE NOTED ACROSS THE NORTHERN PRAIRIES. A LEE TROUGH WAS ALSO NOTED ACROSS EASTERN COLORADO. A RIDGE AXIS OF HIGH PRESSURE EXTENDED FROM THE NORTHERN GULF NE TO NEW ENGLAND. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 343 PM CST WED NOV 21 2012 FOR THE TIME PERIOD TONIGHT AND TOMORROW, THE GREATEST CHALLENGE IN THE FORECAST WILL BE LOWS TONIGHT AND HOW MUCH CLOUD COVER AND WIND WILL INFLUENCE OVERNIGHT TEMPERATURES. THE PREVIOUS FORECAST ALREADY HAD A FAIRLY TIGHT GRADIENT IN LOW TEMPERATURES TONIGHT (FROM 33F ACROSS FAR WEST CENTRAL KANSAS TO AROUND 51F ACROSS FAR SOUTH CENTRAL KANSAS). THESE LOOK GOOD FOR THE MOST PART, BUT THE LATEST RAP AND NAM12 MODELS SUGGEST TEMPERATURES WILL NOT GET MUCH BELOW 60F SOUTHEAST OF A GREAT BEND TO ASHLAND LINE, AND GIVEN THE SEMI OPAQUE SKY COVER FROM 300-500MB CLOUD (FROM THE SUBTROPICAL SHORTWAVE TROUGH) AND THE SOUTHWEST WINDS CONTINUING 12 TO 16 KNOTS IN THESE AREAS, REALLY CANNOT ARGUE AGAINST THESE WARM TEMPERATURES TONIGHT. AS A RESULT, I HAVE BUMPED UP MIN TEMPS ABOUT 2 TO 4 DEGREES AND MOVED THE GRADIENT WESTWARD ABOUT 30 MILES OR SO (EFFECTIVELY WARMING UP DODGE CITY LOW QUITE A BIT). THE FORECAST FOR THANKSGIVING DAY WILL BE A LITTLE LESS COMPLICATED AS MID-HIGH LEVEL CLOUD COVER WILL BE MOVING EAST OF THE AREA WITH SURFACE WINDS BECOMING NORTHWESTERLY. WHILE COLD ADVECTION WILL EXIST BEHIND THE FRONT, THE AIRMASS WILL BE MODIFIED BY DOWNSLOPE AND INSOLATION WILL ALSO COUNTER THE COLD ADVECTION. HIGHS WILL STILL BE ABOVE AVERAGE FOR THE DATE WITH TEMPERATURES WARMING INTO THE 60S (LOWER 70S SOUTH CENTRAL KS). WITH THE INITIAL ISALLOBARIC WIND SURGE/PRESSURE RISE WITH THE PASSAGE OF THE FRONT, WIND SPEEDS WILL BE 22 TO 26 KNOTS MUCH LIKE TODAY, BUT THESE SPEEDS SHOULD ONLY OCCUR DURING ABOUT A 3 OR 4 HOUR PERIOD BEFORE WINDS GRADUALLY DECREASE BACK DOWN TO THE 18 TO 22 KT RANGE LATE IN THE DAY. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 248 PM CST WED NOV 21 2012 BY THE BEGINNING OF THE EXTENDED PERIOD ON THURSDAY NIGHT, A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING OUT OF THE NORTHERN PLAINS INTO THE MIDWESTERN STATES AND GREAT LAKES REGION. A COLD FRONT WILL BE LOCATED OVER SOUTHEAST KANSAS INTO WEST TEXAS. HIGH PRESSURE WILL BE BUILDING INTO WESTERN KANSAS BEHIND THE FRONT THURSDAY NIGHT THROUGH FRIDAY. THE 12Z MODEL TEMPERATURE FORECASTS ARE COMING IN COOLER THAN PREVIOUS RUNS WHICH SEEMS REASONABLE GIVEN THE ONGOING COLD AIR ADVECTION. INTO THIS WEEKEND, FLAT UPPER LEVEL RIDGING WILL SPREAD EAST ACROSS THE WESTERN AND CENTRAL PART OF THE COUNTRY. ANOTHER SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON SATURDAY BEHIND THE RIDGE AND THIS FEATURE WILL BE DIGGING SOME AS IT MOVES INTO THE CENTRAL HIGH PLAINS BY MONDAY NIGHT. THROUGH THIS WEEKEND THE DRY FORECAST WILL CONTINUE WITH TEMPERATURES WILL MODERATE BACK INTO THE 60S. LEE SIDE TROUGHING WILL DEVELOP ON SATURDAY. THIS WILL DEVELOP INTO A LOW PRESSURE AREA THAT MOVES INTO THE OKLAHOMA AND TEXAS PANHANDLES BY SUNDAY EVENING AS THE NEXT UPPER TROUGH APPROACHES. THIS WILL BRING A SWITCH IN THE SURFACE WINDS BACK AROUND TO THE EAST TO NORTHEAST ON SUNDAY. THIS WAVE WILL MOVE OUT ACROSS THE CENTRAL AND NORTHERN PLAINS MONDAY NIGHT. THERE DOES NOT APPEAR TO BE SUFFICIENT MOISTURE AVAILABLE FOR THIS SYSTEM TO WORK WITH. THE BEST CHANCES FOR MEASURABLE PRECIPITATION WILL BE ALONG THE EASTERN SLOPES OF THE ROCKIES AND OVER EASTERN KANSAS INTO THE MID MISSISSIPPI VALLEY. HIGH TEMPERATURES WILL DROP BACK INTO THE 40S ON MONDAY AND TUESDAY. THE REMAINDER OF THE EXTENDED PERIOD WILL SEE AN UPPER LEVEL RIDGE BUILDING OVER THE CENTRAL PART OF THE COUNTRY. THIS WILL RESULT IN TEMPERATURES MODERATING BACK INTO THE 60S LATER NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1100 PM CST WED NOV 21 2012 A COLD FRONT WILL TRAVERSE ACROSS THE REGION THIS MORNING. WINDS WILL INCREASE NORTHERLY 20-25 KT THROUGH LATE MORNING INTO THE EARLY AFTERNOON VIA MIXING/MOMENTUM TRANSFER DOWNWARD. WINDS WILL DECREASE 10-15 KT BY DUSK. OTHER THAN SOME MID TO HIGH LEVEL CLOUDS, CIGS WILL REMAIN VFR. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 66 24 53 / 0 0 0 0 GCK 41 64 22 53 / 0 0 0 0 EHA 41 65 23 53 / 0 0 0 0 LBL 47 67 24 55 / 0 0 0 0 HYS 42 63 21 51 / 0 0 0 0 P28 55 72 28 53 / 10 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...UMSCHEID LONG TERM...GERARD AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1023 PM CST WED NOV 21 2012 ...UPDATE TO SYNOPSIS... .SYNOPSIS... ISSUED AT 1023 PM CST WED NOV 21 2012 THE 22.00Z 250 HPA MAP SHOWED A 100 KT NORTHWESTERLY JET ACROSS THE PACIFIC NORTHWEST ON THE UPSTREAM SIDE OF A LONGWAVE TROF LOCATED ACROSS THE NORTHERN ROCKIES. ANOTHER JET STREAK OF AROUND 110 KT WAS FOUND ON THE BASE OF A VERY AMPLIFIED TROF LOCATED ACROSS FLORIDA AND THE SW ATLANTIC BASIN. A VERY SUBTLE WIND MAX AROUND 50 KT WAS ALSO OBSERVED AT KDDC (DODGE CITY, KS). AT 500 HPA, VERY COLD MID LEVEL TEMPS OF -30 DEG C TO -35 DEG C WERE OBSERVED ACROSS THE PACIFIC NORTHWEST. CLOSER TO HOME, SOME MID LEVEL MOISTURE WAS NOTED ACROSS WEST TEXAS AHEAD OF A WEAK PRESSURE PERTURBATION. DRY AIR ADVECTION WAS NOTED ACROSS THE DEEP SOUTH IN THE WAKE OF THE AFOREMENTIONED UL DISTURBANCE. AT 700 HPA, TEMPS WERE WARM ACROSS THE CENTRAL PLAINS FOR NOVEMBER STANDARDS WITH MANY LOCATIONS REPORTING IN THE 5 DEG C TO 8 DEG C RANGE. THE ATMOSPHERE WAS FAIRLY DRY IN THIS AREA AS WELL. 850 HPA TEMPS ACROSS THE PLAINS WERE WARM WITH A DRY/ADIABATICALLY MIXED PROFILE ACROSS KANSAS. TEMPS AROUND 15 DEG C TO 17 DEG C WERE COMMON FROM WEST TEXAS TO MINNESOTA. AT THE SFC, TWO FRONTAL SYSTEMS WERE NOTED ACROSS THE NORTHERN PRAIRIES. A LEE TROUGH WAS ALSO NOTED ACROSS EASTERN COLORADO. A RIDGE AXIS OF HIGH PRESSURE EXTENDED FROM THE NORTHERN GULF NE TO NEW ENGLAND. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 343 PM CST WED NOV 21 2012 FOR THE TIME PERIOD TONIGHT AND TOMORROW, THE GREATEST CHALLENGE IN THE FORECAST WILL BE LOWS TONIGHT AND HOW MUCH CLOUD COVER AND WIND WILL INFLUENCE OVERNIGHT TEMPERATURES. THE PREVIOUS FORECAST ALREADY HAD A FAIRLY TIGHT GRADIENT IN LOW TEMPERATURES TONIGHT (FROM 33F ACROSS FAR WEST CENTRAL KANSAS TO AROUND 51F ACROSS FAR SOUTH CENTRAL KANSAS). THESE LOOK GOOD FOR THE MOST PART, BUT THE LATEST RAP AND NAM12 MODELS SUGGEST TEMPERATURES WILL NOT GET MUCH BELOW 60F SOUTHEAST OF A GREAT BEND TO ASHLAND LINE, AND GIVEN THE SEMI OPAQUE SKY COVER FROM 300-500MB CLOUD (FROM THE SUBTROPICAL SHORTWAVE TROUGH) AND THE SOUTHWEST WINDS CONTINUING 12 TO 16 KNOTS IN THESE AREAS, REALLY CANNOT ARGUE AGAINST THESE WARM TEMPERATURES TONIGHT. AS A RESULT, I HAVE BUMPED UP MIN TEMPS ABOUT 2 TO 4 DEGREES AND MOVED THE GRADIENT WESTWARD ABOUT 30 MILES OR SO (EFFECTIVELY WARMING UP DODGE CITY LOW QUITE A BIT). THE FORECAST FOR THANKSGIVING DAY WILL BE A LITTLE LESS COMPLICATED AS MID-HIGH LEVEL CLOUD COVER WILL BE MOVING EAST OF THE AREA WITH SURFACE WINDS BECOMING NORTHWESTERLY. WHILE COLD ADVECTION WILL EXIST BEHIND THE FRONT, THE AIRMASS WILL BE MODIFIED BY DOWNSLOPE AND INSOLATION WILL ALSO COUNTER THE COLD ADVECTION. HIGHS WILL STILL BE ABOVE AVERAGE FOR THE DATE WITH TEMPERATURES WARMING INTO THE 60S (LOWER 70S SOUTH CENTRAL KS). WITH THE INITIAL ISALLOBARIC WIND SURGE/PRESSURE RISE WITH THE PASSAGE OF THE FRONT, WIND SPEEDS WILL BE 22 TO 26 KNOTS MUCH LIKE TODAY, BUT THESE SPEEDS SHOULD ONLY OCCUR DURING ABOUT A 3 OR 4 HOUR PERIOD BEFORE WINDS GRADUALLY DECREASE BACK DOWN TO THE 18 TO 22 KT RANGE LATE IN THE DAY. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 248 PM CST WED NOV 21 2012 BY THE BEGINNING OF THE EXTENDED PERIOD ON THURSDAY NIGHT, A STRONG UPPER LEVEL SHORTWAVE TROUGH WILL BE MOVING OUT OF THE NORTHERN PLAINS INTO THE MIDWESTERN STATES AND GREAT LAKES REGION. A COLD FRONT WILL BE LOCATED OVER SOUTHEAST KANSAS INTO WEST TEXAS. HIGH PRESSURE WILL BE BUILDING INTO WESTERN KANSAS BEHIND THE FRONT THURSDAY NIGHT THROUGH FRIDAY. THE 12Z MODEL TEMPERATURE FORECASTS ARE COMING IN COOLER THAN PREVIOUS RUNS WHICH SEEMS REASONABLE GIVEN THE ONGOING COLD AIR ADVECTION. INTO THIS WEEKEND, FLAT UPPER LEVEL RIDGING WILL SPREAD EAST ACROSS THE WESTERN AND CENTRAL PART OF THE COUNTRY. ANOTHER SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST ON SATURDAY BEHIND THE RIDGE AND THIS FEATURE WILL BE DIGGING SOME AS IT MOVES INTO THE CENTRAL HIGH PLAINS BY MONDAY NIGHT. THROUGH THIS WEEKEND THE DRY FORECAST WILL CONTINUE WITH TEMPERATURES WILL MODERATE BACK INTO THE 60S. LEE SIDE TROUGHING WILL DEVELOP ON SATURDAY. THIS WILL DEVELOP INTO A LOW PRESSURE AREA THAT MOVES INTO THE OKLAHOMA AND TEXAS PANHANDLES BY SUNDAY EVENING AS THE NEXT UPPER TROUGH APPROACHES. THIS WILL BRING A SWITCH IN THE SURFACE WINDS BACK AROUND TO THE EAST TO NORTHEAST ON SUNDAY. THIS WAVE WILL MOVE OUT ACROSS THE CENTRAL AND NORTHERN PLAINS MONDAY NIGHT. THERE DOES NOT APPEAR TO BE SUFFICIENT MOISTURE AVAILABLE FOR THIS SYSTEM TO WORK WITH. THE BEST CHANCES FOR MEASURABLE PRECIPITATION WILL BE ALONG THE EASTERN SLOPES OF THE ROCKIES AND OVER EASTERN KANSAS INTO THE MID MISSISSIPPI VALLEY. HIGH TEMPERATURES WILL DROP BACK INTO THE 40S ON MONDAY AND TUESDAY. THE REMAINDER OF THE EXTENDED PERIOD WILL SEE AN UPPER LEVEL RIDGE BUILDING OVER THE CENTRAL PART OF THE COUNTRY. THIS WILL RESULT IN TEMPERATURES MODERATING BACK INTO THE 60S LATER NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 505 PM CST WED NOV 21 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH EARLY THURSDAY AFTERNOON. AS FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE IN EXTREME EASTERN COLORADO WILL BEGIN EDGING EAST INTO WESTERN KANSAS THIS EVENING. AS A RESULT, SOUTHERLY WINDS OF 15 TO 25KT EARLY THIS EVENING WILL BECOME MORE SOUTHWESTERLY WHILE DECREASING 5 TO 15KT OVERNIGHT. A COLD FRONT IS THEN EXPECTED TO PUSH SOUTHEAST ACROSS WESTERN KANSAS EARLY THURSDAY MORNING TURNING WINDS NORTHERLY 25 TO 35KT BY MID DAY THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 52 66 24 53 / 0 0 0 0 GCK 41 64 22 53 / 0 0 0 0 EHA 41 65 23 53 / 0 0 0 0 LBL 47 67 24 55 / 0 0 0 0 HYS 42 63 21 51 / 0 0 0 0 P28 55 72 28 53 / 10 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...UMSCHEID LONG TERM...GERARD AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1243 PM EST THU NOV 22 2012 .SYNOPSIS... ISSUED AT 341 AM EST THU NOV 22 2012 A WINDY AND WARM THANKSGIVING DAY IS ON TAP FOR LOWER MICHIGAN. TEMPERATURES WILL WARM INTO THE LOWER 60S AS GUSTY SOUTHERLY WINDS BRING THE WARM AIR UP INTO MICHIGAN. THE WARMER AIR WILL BE SHORT LIVED HOWEVER AS A STRONG COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT. RAIN SHOWERS AND EVEN A SLIGHT CHANCE OF A RUMBLE OF THUNDER WILL BE POSSIBLE. THE COLDER AIR WILL FILTER INTO THE AREA DURING THE DAY ON FRIDAY. TEMPERATURES WILL FALL THROUGH THE DAY INTO THE 30S. RAIN SHOWERS WILL CHANGE OVER TO SNOW SHOWERS. SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE FOR THE LAKESHORE COMMUNITIES. && .UPDATE... ISSUED AT 1122 AM EST THU NOV 22 2012 I DID SOME SIGNIFICANT GRID UPDATES LATE THIS MORNING. I UPDATED THE START OF THE GALE WARNING AND I INCREASED THE POP FOR BOTH TONIGHT AND FRIDAY. BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM. THE NAM12 IS NOW SHOWING DEEPER MOISTURE FOR BOTH THE PRECIPITATION EVENT TONIGHT AND THE LAKE ENHANCED SNOW FOR FRIDAY AFTERNOON INTO SATURDAY MORNING. FOR THE MOST PART MY POP GRID IS REALLY BASED ON THE LIFT IN THE SATURATED DGZ GRID FROM THE NAM12. THAT HAS TIME AND AGAIN SHOWN ME TO BE THE MOST RELIABLE TOOL FOR FORECASTING PRECIPITATION (RAIN/SNOW AND EVEN TIMING OF THUNDERSTORMS IF THAT IS APPROPRIATE). THE SOUTHERN STREAM MOISTURE (SEEN WELL ON THE WATER VAPOR LOOPS) IS STREAMING NORTHEAST AND WILL RUN INTO THE FRONTAL ZONE LIFT BY MID AFTERNOON. THIS SHOULD HAVE NO PROBLEM SPARKING SHOWERS AND ISOLATED THUNDERSTORMS AS THERE IS A 50 - 70 KNOT LOW LEVEL JET WITH PRECIPITABLE WATER VALUES OVER 300 PCT OF NORMAL JUST AHEAD OF THE FRONT. I SEE NO REASON WHY I SHOULD NOT GO CONDITIONAL GIVEN THE DEEP MOISTURE...STRONG LIFT AND STRONG FRONT WITH A GOOD SOUTHERN STREAM SHORTWAVE. AS FOR FRIDAY... THERE IS NOW BETTER LIFT IN THE DGZ ON THE NAM12 FOR THE LAKE EFFECT SNOW EVENT FRIDAY INTO FRIDAY NIGHT. I HAVE TO LOOK AT THIS MORE CLOSELY BY WE MAY HAVE TO INCREASE SNOWFALL AMOUNTS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 341 AM EST THU NOV 22 2012 MAIN CHALLENGES IN THE SHORT TERM PORTION OF THE FCST REVOLVE AROUND RAIN CHANCES TONIGHT...AND LAKE EFFECT TRENDS FRI THROUGH SAT. THE ONLY REAL CHANGE TO THE FCST WAS TO SLIP A SLIGHT CHC MENTION OF THUNDER IN THE FCST FOR LATE THIS AFTERNOON AND EVENING. MANY OBSERVATIONS THIS MORNING ARE TRYING TO DROP THE VISIBILITIES IN FOG. SITES ARE DOWN TO BETWEEN 1-4SM. THEY HAVE STABILIZED AS IT APPEARS THE WINDS ALOFT...AND RESIDUAL BREEZE AT THE SURFACE ARE KEEPING CONDITIONS FROM DROPPING TOO MUCH. WE DO NOT EXPECT TO HAVE TO ISSUE ANY FOG HEADLINES THIS MORNING. THE FIRST 2/3RDS OF THE DAY TODAY LOOKS QUITE NICE. WE SHOULD SEE A GOOD DEAL OF SUNSHINE INTO THE FIRST PORTION OF THE AFTERNOON WITH ONLY SOME HIGH CLOUDS MOVING THROUGH. IT WILL BE BREEZY WITH WIND GUSTS APPROACHING 30 MPH IF NOT ECLIPSING IT AT TIMES. WE WILL SEE THE MOISTURE TRANSPORT PICK UP SIGNIFICANTLY BETWEEN 18Z AND 00Z TONIGHT AS THE LOW LEVEL JET AXIS MOVES OVERHEAD. WE SHOULD SEE THE MOSTLY SUNNY SKIES TURN MOSTLY CLOUDY PRETTY QUICK LATER THIS AFTERNOON. DEEP ENOUGH MOISTURE IS FOUND ACROSS THE WRN COUNTIES WHERE ANY RAIN THAT FORMS COULD REACH THE GROUND BY 00Z. THE BEST THREAT OF RAIN WILL COME BETWEEN 00Z AND 09Z TONIGHT...AND ACROSS THE SE 2/3RDS OF THE CWFA. THIS IS WHERE THE DEEPEST MOISTURE COMES TOGETHER DUE TO THE WAY THE UPPER MOISTURE ADVECTS INTO THE AREA AHEAD OF THE WAVE. AS MENTIONED ABOVE...WE HAVE ADDED THUNDER TO THE FCST. MODELS ARE INDICATING A LITTLE MORE ELEVATED INSTABILITY PRESENT THAN 24 HOURS AGO. SEVERE THREAT SHOULD REMAIN RATHER LOW DUE TO THE GENERAL NATURE OF THE ELEVATED INSTABILITY. THE STRONG LOW LEVEL JET IS SOME CAUSE FOR CONCERN AS IT WOULDN/T TAKE MUCH TO MIX IT DOWN. HOWEVER...ONCE AGAIN THE ELEVATED NATURE OF THE INSTABILITY SHOULD LIMIT THE SEVERE POTENTIAL. WE WILL SEE THE DRY SLOT TRAVERSE THE AREA BETWEEN 09Z AND 15Z FRI. AFTER 15Z...WE SEE THE WRAP AROUND MOISTURE ROTATE BACK IN ACROSS THE AREA. H850 TEMPS DROP PRETTY QUICK AT THIS TIME TO EVENTUALLY AROUND -10C. WE EXPECT THAT THE WRAP AROUND MOISTURE WILL START OUT AS SOME RAIN AND/OR SNOW SHOWERS THAT WILL TRANSITION TO ALL SNOW SHOWERS PRETTY QUICKLY. A FEW SCATTERED SYNOPTIC SNOW SHOWERS WILL REMAIN POSSIBLE. THE FOCUS WILL TURN ON LAKE EFFECT BY LATE FRI AFTERNOON. DELTA T/S WILL BE APPROACHING 20C. WE WILL HAVE CYCLONIC FLOW ALOFT. MOISTURE WILL BE SOMEWHAT LIMITED...WITH INVERSION HEIGHTS AROUND 7-8K FT. THE BEST LIFT IS BELOW THE DGZ SO WE DO NOT EXPECT SIGNIFICANT SNOW RATES. THE FLOW WILL TRANSITION FROM WNW TO PURE NW BY 00Z SAT. THIS WILL LAST INTO THE FIRST HALF OF SAT. WE ARE EXPECTING THAT A COUPLE OF LOCATIONS MAY SEE AN INCH OR TWO FROM LATE FRI INTO MIDDAY SAT. THE UPPER LOW WILL LIFT OUT OF THE AREA SAT AFTERNOON. THE UPPER FLOW BECOMES ANTI-CYCLONIC BY 18Z...LIMITING THE MOISTURE DEPTH QUITE A BIT. WE SHOULD SEE SNOW SHOWERS DIMINISH BY SAT AFTERNOON...AND ANYTHING LEFT SPREADING INLAND ONCE AGAIN WITH THE WRLY WIND SETTING UP WITH THE SFC HIGH MOVING THOUGH. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 341 AM EST THU NOV 22 2012 MODEL DISCREPANCIES CONTINUE IN THE LONG TERM PERIOD...ESPECIALLY IN REGARD TO WHAT WOULD BE THE MOST SIGNIFICANT PRECIPITATION POTENTIAL DURING THE PERIOD...THE SYSTEM FOR NEXT TUESDAY. FIRST THOUGH A WEAK SYSTEM WILL PROGRESS EAST ACROSS THE NORTHERN GREAT LAKES SATURDAY NIGHT INTO SUNDAY. COULD BE A LITTLE LIGHT SNOW ACROSS CENTRAL LOWER...BUT NOT EXPECTING MUCH. FOCUS THEN SHIFTS TO A POTENTIAL SYSTEM FOR TUESDAY INTO TUESDAY NIGHT. THE GFS HAS A STRONGER MORE NORTHERN TRACK...WHILE THE ECMWF WOULD BE WELL SOUTH AND WEAKER. AT THIS POINT CONFIDENCE IS NOT HIGH IN WHICH SOLUTION IS MOST LIKELY TO VERIFY. GIVEN THE TYPICALLY BETTER TRACK RECORD OF THE ECMWF IN THE 4-7 DAY PERIOD WOULD LEAN TOWARD THE DRIER SOLUTION. THE GFS WOULD YIELD ACCUMULATING SNOW ACROSS THE FORECAST AREA. CHANCE POPS IN THE FORECAST AT THIS POINT. INTO WEDNESDAY THE ECMWF BRINGS A SHORTWAVE THROUGH ACCOMPANIED BY SOME LIGHT SNOW AND LAKE ENHANCEMENT. MODEL DISCREPANCIES CONTINUE INTO THIS TIME FRAME WITH THE GFS INDICATING DRY WX. SUFFICE IT TO SAY AN OVERALL LOW CONFIDENCE FORECAST IN THE LONG TERM. TEMPERATURES LOOK TO BE BELOW NORMAL THROUGH THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM EST THU NOV 22 2012 MAIN AVIATION CONCERN THROUGH THIS AFTERNOON WILL BE THE SOUTHERLY WINDS WHICH WILL GUST 20 TO 25 KTS. THESE ARE EXPECTED TO TAPER OFF SOMEWHAT BY NIGHTFALL. A STRONG COLD WILL BRING IN LOWER CEILINGS ALONG WITH RAIN SHOWERS AND EVEN MORE WIND LATE TONIGHT. DUE TO THE AMOUNT OF MIXING EXPECTED...MOST LOCATIONS WILL ONLY DIP DOWN TO MVFR WITH VERY PATCHY IFR NEAR AND JUST BEHIND THE FRONT. CAN NOT COMPLETELY RULE OUT A THUNDERSTORM WITH THE FRONT...BUT HAVE LEFT THAT OUT OF THE TAFS AS ANY THUNDER SHOULD REMAIN VERY ISOLATED. A DRY SLOT IS EXPECTED TO ROLL IN AROUND DAYBREAK. SO WE WILL LIKELY SEE A PERIOD OF HIGHER CEILINGS AND VSBYS WITH THIS. HOWEVER AS COLDER AIR EVADES THE REGION THROUGH THE MID FRI MORNING HOURS LAKE EFFECT CLOUDS AND SNOW SHOWERS CAN BE EXPECTED. WITH WNW FLOW EXPECT SOME AREAS OF IFR TO DEVELOP IN LOWERING VSBYS AFTER ABOUT 14-16Z FRI. && .MARINE... ISSUED AT 1122 AM EST THU NOV 22 2012 I BROUGHT FORWARD IN TIME THE START OF THE GALE WARING FROM 10 PM TO 4 PM. THIS IDEA IS BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM. && .HYDROLOGY... ISSUED AT 341 AM EST THU NOV 22 2012 WE CONTINUE TO EXPECT NO HYDROLOGY ISSUES THROUGH THIS FCST PERIOD. WE ARE EXPECTING A QUICK SHOT OF RAINFALL WITH THE FRONT VERY LATE TODAY AND MORE SO TONIGHT. RAINFALL AMOUNTS SHOULD RANGE FROM A TENTH OR TWO UP NORTH...UP TO AS MUCH AS HALF AN INCH. RIVER AND STREAM LEVELS CONTINUE TO FLOW BELOW AVERAGE. SOME LAKE EFFECT SNOW SHOWERS WILL BE AROUND FRIDAY...BUT THIS SHOULD NOT HAVE A LOT OF WATER CONTENT IN IT. MINIMAL RISES CAN BE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ844>849. GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST FRIDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...DUKE AVIATION...JK HYDROLOGY...NJJ MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1122 AM EST THU NOV 22 2012 .SYNOPSIS... ISSUED AT 341 AM EST THU NOV 22 2012 A WINDY AND WARM THANKSGIVING DAY IS ON TAP FOR LOWER MICHIGAN. TEMPERATURES WILL WARM INTO THE LOWER 60S AS GUSTY SOUTHERLY WINDS BRING THE WARM AIR UP INTO MICHIGAN. THE WARMER AIR WILL BE SHORT LIVED HOWEVER AS A STRONG COLD FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT. RAIN SHOWERS AND EVEN A SLIGHT CHANCE OF A RUMBLE OF THUNDER WILL BE POSSIBLE. THE COLDER AIR WILL FILTER INTO THE AREA DURING THE DAY ON FRIDAY. TEMPERATURES WILL FALL THROUGH THE DAY INTO THE 30S. RAIN SHOWERS WILL CHANGE OVER TO SNOW SHOWERS. SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE FOR THE LAKESHORE COMMUNITIES. && .UPDATE... ISSUED AT 1122 AM EST THU NOV 22 2012 I DID SOME SIGNIFICANT GRID UPDATES LATE THIS MORNING. I UPDATED THE START OF THE GALE WARNING AND I INCREASED THE POP FOR BOTH TONIGHT AND FRIDAY. BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM. THE NAM12 IS NOW SHOWING DEEPER MOISTURE FOR BOTH THE PRECIPITATION EVENT TONIGHT AND THE LAKE ENHANCED SNOW FOR FRIDAY AFTERNOON INTO SATURDAY MORNING. FOR THE MOST PART MY POP GRID IS REALLY BASED ON THE LIFT IN THE SATURATED DGZ GRID FROM THE NAM12. THAT HAS TIME AND AGAIN SHOWN ME TO BE THE MOST RELIABLE TOOL FOR FORECASTING PRECIPITATION (RAIN/SNOW AND EVEN TIMING OF THUNDERSTORMS IF THAT IS APPROPRIATE). THE SOUTHERN STREAM MOISTURE (SEEN WELL ON THE WATER VAPOR LOOPS) IS STREAMING NORTHEAST AND WILL RUN INTO THE FRONTAL ZONE LIFT BY MID AFTERNOON. THIS SHOULD HAVE NO PROBLEM SPARKING SHOWERS AND ISOLATED THUNDERSTORMS AS THERE IS A 50 - 70 KNOT LOW LEVEL JET WITH PRECIPITABLE WATER VALUES OVER 300 PCT OF NORMAL JUST AHEAD OF THE FRONT. I SEE NO REASON WHY I SHOULD NOT GO CONDITIONAL GIVEN THE DEEP MOISTURE...STRONG LIFT AND STRONG FRONT WITH A GOOD SOUTHERN STREAM SHORTWAVE. AS FOR FRIDAY... THERE IS NOW BETTER LIFT IN THE DGZ ON THE NAM12 FOR THE LAKE EFFECT SNOW EVENT FRIDAY INTO FRIDAY NIGHT. I HAVE TO LOOK AT THIS MORE CLOSELY BY WE MAY HAVE TO INCREASE SNOWFALL AMOUNTS. && .SHORT TERM...(TODAY THROUGH SATURDAY) ISSUED AT 341 AM EST THU NOV 22 2012 MAIN CHALLENGES IN THE SHORT TERM PORTION OF THE FCST REVOLVE AROUND RAIN CHANCES TONIGHT...AND LAKE EFFECT TRENDS FRI THROUGH SAT. THE ONLY REAL CHANGE TO THE FCST WAS TO SLIP A SLIGHT CHC MENTION OF THUNDER IN THE FCST FOR LATE THIS AFTERNOON AND EVENING. MANY OBSERVATIONS THIS MORNING ARE TRYING TO DROP THE VISIBILITIES IN FOG. SITES ARE DOWN TO BETWEEN 1-4SM. THEY HAVE STABILIZED AS IT APPEARS THE WINDS ALOFT...AND RESIDUAL BREEZE AT THE SURFACE ARE KEEPING CONDITIONS FROM DROPPING TOO MUCH. WE DO NOT EXPECT TO HAVE TO ISSUE ANY FOG HEADLINES THIS MORNING. THE FIRST 2/3RDS OF THE DAY TODAY LOOKS QUITE NICE. WE SHOULD SEE A GOOD DEAL OF SUNSHINE INTO THE FIRST PORTION OF THE AFTERNOON WITH ONLY SOME HIGH CLOUDS MOVING THROUGH. IT WILL BE BREEZY WITH WIND GUSTS APPROACHING 30 MPH IF NOT ECLIPSING IT AT TIMES. WE WILL SEE THE MOISTURE TRANSPORT PICK UP SIGNIFICANTLY BETWEEN 18Z AND 00Z TONIGHT AS THE LOW LEVEL JET AXIS MOVES OVERHEAD. WE SHOULD SEE THE MOSTLY SUNNY SKIES TURN MOSTLY CLOUDY PRETTY QUICK LATER THIS AFTERNOON. DEEP ENOUGH MOISTURE IS FOUND ACROSS THE WRN COUNTIES WHERE ANY RAIN THAT FORMS COULD REACH THE GROUND BY 00Z. THE BEST THREAT OF RAIN WILL COME BETWEEN 00Z AND 09Z TONIGHT...AND ACROSS THE SE 2/3RDS OF THE CWFA. THIS IS WHERE THE DEEPEST MOISTURE COMES TOGETHER DUE TO THE WAY THE UPPER MOISTURE ADVECTS INTO THE AREA AHEAD OF THE WAVE. AS MENTIONED ABOVE...WE HAVE ADDED THUNDER TO THE FCST. MODELS ARE INDICATING A LITTLE MORE ELEVATED INSTABILITY PRESENT THAN 24 HOURS AGO. SEVERE THREAT SHOULD REMAIN RATHER LOW DUE TO THE GENERAL NATURE OF THE ELEVATED INSTABILITY. THE STRONG LOW LEVEL JET IS SOME CAUSE FOR CONCERN AS IT WOULDN/T TAKE MUCH TO MIX IT DOWN. HOWEVER...ONCE AGAIN THE ELEVATED NATURE OF THE INSTABILITY SHOULD LIMIT THE SEVERE POTENTIAL. WE WILL SEE THE DRY SLOT TRAVERSE THE AREA BETWEEN 09Z AND 15Z FRI. AFTER 15Z...WE SEE THE WRAP AROUND MOISTURE ROTATE BACK IN ACROSS THE AREA. H850 TEMPS DROP PRETTY QUICK AT THIS TIME TO EVENTUALLY AROUND -10C. WE EXPECT THAT THE WRAP AROUND MOISTURE WILL START OUT AS SOME RAIN AND/OR SNOW SHOWERS THAT WILL TRANSITION TO ALL SNOW SHOWERS PRETTY QUICKLY. A FEW SCATTERED SYNOPTIC SNOW SHOWERS WILL REMAIN POSSIBLE. THE FOCUS WILL TURN ON LAKE EFFECT BY LATE FRI AFTERNOON. DELTA T/S WILL BE APPROACHING 20C. WE WILL HAVE CYCLONIC FLOW ALOFT. MOISTURE WILL BE SOMEWHAT LIMITED...WITH INVERSION HEIGHTS AROUND 7-8K FT. THE BEST LIFT IS BELOW THE DGZ SO WE DO NOT EXPECT SIGNIFICANT SNOW RATES. THE FLOW WILL TRANSITION FROM WNW TO PURE NW BY 00Z SAT. THIS WILL LAST INTO THE FIRST HALF OF SAT. WE ARE EXPECTING THAT A COUPLE OF LOCATIONS MAY SEE AN INCH OR TWO FROM LATE FRI INTO MIDDAY SAT. THE UPPER LOW WILL LIFT OUT OF THE AREA SAT AFTERNOON. THE UPPER FLOW BECOMES ANTI-CYCLONIC BY 18Z...LIMITING THE MOISTURE DEPTH QUITE A BIT. WE SHOULD SEE SNOW SHOWERS DIMINISH BY SAT AFTERNOON...AND ANYTHING LEFT SPREADING INLAND ONCE AGAIN WITH THE WRLY WIND SETTING UP WITH THE SFC HIGH MOVING THOUGH. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 341 AM EST THU NOV 22 2012 MODEL DISCREPANCIES CONTINUE IN THE LONG TERM PERIOD...ESPECIALLY IN REGARD TO WHAT WOULD BE THE MOST SIGNIFICANT PRECIPITATION POTENTIAL DURING THE PERIOD...THE SYSTEM FOR NEXT TUESDAY. FIRST THOUGH A WEAK SYSTEM WILL PROGRESS EAST ACROSS THE NORTHERN GREAT LAKES SATURDAY NIGHT INTO SUNDAY. COULD BE A LITTLE LIGHT SNOW ACROSS CENTRAL LOWER...BUT NOT EXPECTING MUCH. FOCUS THEN SHIFTS TO A POTENTIAL SYSTEM FOR TUESDAY INTO TUESDAY NIGHT. THE GFS HAS A STRONGER MORE NORTHERN TRACK...WHILE THE ECMWF WOULD BE WELL SOUTH AND WEAKER. AT THIS POINT CONFIDENCE IS NOT HIGH IN WHICH SOLUTION IS MOST LIKELY TO VERIFY. GIVEN THE TYPICALLY BETTER TRACK RECORD OF THE ECMWF IN THE 4-7 DAY PERIOD WOULD LEAN TOWARD THE DRIER SOLUTION. THE GFS WOULD YIELD ACCUMULATING SNOW ACROSS THE FORECAST AREA. CHANCE POPS IN THE FORECAST AT THIS POINT. INTO WEDNESDAY THE ECMWF BRINGS A SHORTWAVE THROUGH ACCOMPANIED BY SOME LIGHT SNOW AND LAKE ENHANCEMENT. MODEL DISCREPANCIES CONTINUE INTO THIS TIME FRAME WITH THE GFS INDICATING DRY WX. SUFFICE IT TO SAY AN OVERALL LOW CONFIDENCE FORECAST IN THE LONG TERM. TEMPERATURES LOOK TO BE BELOW NORMAL THROUGH THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 649 AM EST THU NOV 22 2012 FOG GENERALLY BETWEEN 1-4SM ACROSS THE AREA WILL LIFT FAIRLY QUICK AFTER SUNRISE. EXPECT ALL SITES TO BE VFR BY 15Z OR SO. SKIES WILL BE MAINLY CLEAR THROUGH MID AFTERNOON. THE WIND WILL BE THE MAIN WEATHER ISSUE TODAY WITH SOUTH-SOUTHWEST WINDS OF 13-25 KNOTS THROUGH THE COURSE OF THE DAY. RAIN SHOWERS WILL BREAK OUT ACROSS THE AREA BETWEEN 21Z AND 00Z...SPREADING EAST WITH TIME. A RUMBLE OF THUNDER CANNOT BE RULED OUT BETWEEN 22Z AND 05Z...BUT THE THREAT IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME. CEILINGS WILL BE VFR THIS EVENING BEFORE DROPPING TO MVFR AFTER 05Z. && .MARINE... ISSUED AT 1122 AM EST THU NOV 22 2012 I BROUGHT FORWARD IN TIME THE START OF THE GALE WARING FROM 10 PM TO 4 PM. THIS IDEA IS BASED ON THE LATEST DATA FROM BOTH THE NAM12 AND HRRR IT SEEMS TO ME THE WINDS WILL RAMP UP SOONER OVER LAKE MICHIGAN AND OUR NEAR SHORE WATERS. THE NAM12 SOUNDING AT MKG...BIV...LDM AND THE SOUTH BUOY SHOW 40 TO 45 KNOTS IN THE MIX LAYER BY 21Z. CLOUDS MAY BE AN ISSUE BUT AT 21Z I COULD SEE THERE NOT BEING A LOT OF CLOUDS YET. AS A RESULT I BROUGHT FORWARD IN TIME THE START OF THE GALE WARNING TO 4 PM FROM 10 PM. && .HYDROLOGY... ISSUED AT 341 AM EST THU NOV 22 2012 WE CONTINUE TO EXPECT NO HYDROLOGY ISSUES THROUGH THIS FCST PERIOD. WE ARE EXPECTING A QUICK SHOT OF RAINFALL WITH THE FRONT VERY LATE TODAY AND MORE SO TONIGHT. RAINFALL AMOUNTS SHOULD RANGE FROM A TENTH OR TWO UP NORTH...UP TO AS MUCH AS HALF AN INCH. RIVER AND STREAM LEVELS CONTINUE TO FLOW BELOW AVERAGE. SOME LAKE EFFECT SNOW SHOWERS WILL BE AROUND FRIDAY...BUT THIS SHOULD NOT HAVE A LOT OF WATER CONTENT IN IT. MINIMAL RISES CAN BE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LMZ844>849. GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST FRIDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...DUKE AVIATION...DUKE HYDROLOGY...NJJ MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
257 AM EST THU NOV 22 2012 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 437 PM EST WED NOV 21 2012 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR RDG EXTENDING NEWD FM THE SRN PLAINS INTO THE GRT LKS BTWN A TROF ALONG THE E COAST AND ANOTHER ALONG THE W COAST. THE AIRMASS ALOFT IS QUITE WARM AND DRY OVER THE UPR GRT LKS...BUT LO CLDS ENHANCED BY RADIATIONAL COOLING LAST NGT THAT FORMED UNDER SHARP LLVL INVRN SHOWN ON LOCAL 12Z RAOBS ARE PROVING TO BE QUITE RESILIENT OVER THE SCENTRAL AND ERN CWA WITH ADDED MOISTENING OFF LK MI IN SSW FLOW BTWN HI PRES IN THE MID ATLANTIC AND LOWER PRES IN THE PLAINS. THERE IS NO FOG/ST NOTED TO THE W...BUT PLENTY OF HI CLDS ARE STREAMING ENEWD FM THE PLAINS INTO THE UPR LKS IN THE WSW FLOW ALF. A POTENT SHRTWV IS COMING ASHORE IN THE PAC NW. LATE THIS AFTN...LO CLDS PRESENT EARLY THIS AFTN OVER THE SCENTRAL AND E WILL BREAK UP THRU THE AFTN IN THE PRESENCE OF SOME DIURNAL HEATING. THESE CLDS WL BE MOST RESILIENT OVER THE FAR E DOWNWIND OF LK MI AS STLT IMAGERY SHOWS ST DECK EXTENDING ALMOST THE ENTIRE LENGTH OF THE LK. TNGT...ALTHOUGH THE ST SHOULD BE GONE THIS EVNG EXCEPT OVER THE FAR E...SUSPECT THIS LO CLD WL FORM AGAIN TNGT WITH NOCTURNAL COOLING AND PERSISTENT SSW FLOW/LO INVRN SHOWN ON FCST SDNGS. CONFIDENCE IN THIS SCENARIO IS HIER SINCE THE 12Z NAM/LOCAL WRF-ARW SHOW HIER H95-9 SPECIFIC HUMIDITY ADVECTING INTO THE AREA OVERNGT IN THE STRENGTHENING LLVL SSW FLOW. H925 WINDS AS HI AS 30-40KTS BY LATE TNGT SHOULD LIMIT THE POTENTIAL FOR DENSER FOG...BUT STILL ADDED SOME PATCHY FOG OVER THE SCENTRAL AND E AWAY FM MORE PRONOUNCED DOWNSLOPE WARMING OVER THE NW AND NCENTRAL AS MODELS HINT AT A PERIOD OF LIGHTER WINDS THIS EVNG THAT MIGHT AUGMENT A PERIOD OF QUICK COOLING. MIN TEMPS WL REMAIN WELL ABV NORMAL WITH INCRSG WINDS/ QUITE A BIT OF HI CLD...ESPECIALLY IN THE DOWNSLOPE AREAS OVER THE W AND NCENTRAL NEAR LK SUP. THANKSGIVING DAY...WITH DIURNAL HEATING...EXPECT LO CLDS/FOG IN THE MRNG TO BREAK UP BY NOON. BUT WITH PERSISTENT SSW FLOW...THE ST WL MOST LIKELY LINGER LONGER INTO THE AFTN OVER THE E DOWNSTREAM OF LK MI. ATTENTION THEN TURNS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE PAC NW. MODELS SHOW THIS DISTURBANCE MOVING EWD TO OVER MN BY 00Z FRI. ALTHOUGH ASSOCIATED SFC LO PRES IS FCST TO MOVE INTO ONTARIO JUST N OF LK SUP WITH ATTENDANT COLD FNT PROGGED TO REACH CENTRAL UPR MI BY 00Z...DEEP LARGER SCALE FORCING IS FCST TO HANG TO THE W THRU THAT TIME. WITH LINGERING MID LVL DRY AIR...ANY ACCOMPANYING PCPN SHOULD PUSH NO FARTHER THAN WRN LK SUP UNTIL AFT 00Z. OTRW... LOOK FOR ANOTHER DAY OF WELL ABV NORMAL TEMPS UNDER H85 THERMAL RDG UP TO 11C RIGHT AHEAD OF THE FNT. BUT TEMPS OVER THE W SHOULD FALL IN THE AFTN FOLLOWING THE COLD FROPA WITH H85 TEMPS PROGGED TO TUMBLE TOWARD 0C AT IWD BY 00Z FRI. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 437 PM EST WED NOV 21 2012 MODEL HAVE COME INTO MUCH BETTER OVERALL AGREEMENT RELATING TO THE SYSTEM THAT WILL BRING SNOW TO MUCH OF THE AREA THU NIGHT INTO SAT...WITH MAINLY SMALLER SCALE/TIMING DIFFERENCES THAT ARE NOT OUT OF THE NORM FOR THE TIME FRAME OF THE EVENT. A GENERAL MODEL CONSENSUS WAS USED...WITH MOST FORECAST ALIGNMENT WITH THE 12Z/21 NAM/GFS AND TO A SOMEWHAT LESSER DEGREE THE 00Z/21 ECMWF FOCUSED MAJORITY OF ATTENTION ON THE SYSTEM THU NIGHT INTO SAT GIVEN HIGHER IMPACTS FROM POST THANKSGIVING TRAVEL/ACTIVITIES. AT 00Z FRI...MODELS SHOW THE 500MB SHORTWAVE IN THE BEGINNING STAGES OF BEING CLOSED OFF OVER NW MN WITH A 1000MB SFC LOW OVER CENTRAL LAKE SUPERIOR...AND A SFC COLD FRONT FROM THE HURON MOUNTAINS TO IRON OR DICKINSON COUNTY. 850MB TEMPS WILL BE JUST FALLING BELOW 0C OVER FAR WRN UPPER MI...BUT WILL STILL BY AROUND 6C OVER THE ERN CWA. THE MID LEVEL LOW WILL CONTINUE TO STRENGTHEN AS IT MOVES TO THE CENTRAL CWA BY 12Z FRI /AVG LOCATION AMONG PREFERRED MODELS...THERE WERE MINOR TIMING DIFFERENCES/...WITH HEIGHT FALLS OF 7-10DAM FROM 12 HOURS PREVIOUS. BY 12Z FRI THE BULK OF THE SFC LOW WILL HAVE SHIFTED NE INTO ONTARIO...BUT PREFER THE NAM/GEM/ECMWF SOLUTIONS THAT PIN A 998MB SFC LOW OVER NE LAKE SUPERIOR AS OFTEN HAPPENS DUE TO THE WARM LAKE TEMPS. 850MB TEMPS FALL TO -10C TO -12C OVER WRN LAKE SUPERIOR BY 12Z FRI...AND WILL WELL BELOW 0C OVER THE REST OF THE CWA. THE COMBINATION OF THE DEEPENING SFC LOW...COLD AIR OVER THE WARM LAKE AND SHARP PRESSURE GRADIENT LEAD TO STRONG WINDS. THE STRONGEST WINDS LOOK TO BE OVER THE KEWEENAW AND NEAR LAKE SUPERIOR E OF THE HURON MOUNTAINS...ESPECIALLY ALONG THE SHORELINES OF ALGER AND LUCE COUNTIES. IN THESE AREAS...MODELS SHOW 925MB WINDS IN EXCESS OF 40KTS...SO GUSTS AS HIGH AS 40KTS SEEM APPROPRIATE FOR THE FORECAST IN THESE MORE EXPOSED LOCATIONS FROM THE NW WINDS LATE THU NIGHT AND THROUGH MUCH OF FRI. A SHORT SWATH OF DRY LOW AND MID LEVEL AIR ROTATES THROUGH THE WRN CWA LATE FRI MORNING...WHICH WILL DIMINISH SNOWFALL TO SOME EXTENT. MODELS THEN INDICATE ANOTHER SHORTWAVE PUSHING THROUGH SOMETIME SAT EVENING AS 850MB TEMPS FALL TO -14C OVER MUCH OF LAKE SUPERIOR...WHICH WILL ACT TO ENHANCE SNOWFALL RATES. AFTER THIS SHORTWAVE...SNOWFALL SHOULD GENERALLY SLOWLY DIMINISH IN INTENSITY/COVERAGE UNTIL SFC AND UPPER RIDGING MOVES IN FROM THE W SAT...REACHING IWD BY 18Z SAT AND THE FAR ERN CWA AROUND 00Z SUN. GIVEN HOW QUICKLY TEMPS GET COLD AS THE UPPER LOW IS MOVING OVER...SNOW TO LIQUID RATIOS WILL JUMP UP PRETTY QUICKLY TO AROUND 18 TO 1 RATIOS. THIS WILL INCREASE SNOWFALL ACCUMULATIONS AND WILL ALLOW THE SNOW TO BE BLOW AROUND MORE FROM GUSTY WINDS. EXPECT TWO MAIN BURSTS OF SNOW THAT SHOULD BE ESPECIALLY UNTACTFUL...ONE AS THE UPPER LOW PUSHES IN WITH LAKE ENHANCEMENT ADDING TO SNOW INTENSITY. THIS WILL HAPPEN THU NIGHT INTO EARLY FRI MORNING OVER THE WRN CWA...AND FRI MORNING TO AROUND NOON FRI OVER THE ERN CWA. THE SECOND BURST LOOKS TO BE WITH THE SECOND SHORTWAVE FRI EVENING TO EARLY SAT NIGHT WITH ENHANCEMENT OF THE LES. THE FIRST BURST OF SNOW LOOKS TO BE THE WORST GIVEN THE INCREASED FORCING FROM THE 500MB LOW...WHICH WILL ALSO BE AT THE WORST TIMES GIVEN MUCH INCREASED POST THANKSGIVING TRAVEL/ACTIVITY AS FAR A SOCIETAL IMPACTS GO. THIS IS COMPOUNDED BY THE FACT THAT NO SIGNIFICANT SNOWFALL HAS OCCURRED IN A WHILE...WHICH LOCAL STUDIES SUGGEST LEADS TO A LARGE INCREASE IN TRAFFIC ACCIDENTS ONCE SNOW DOES FALL. AS FAR AS SNOWFALL AMOUNTS GO...HAVE HIGHEST CONFIDENCE IN SNOWFALL AMOUNTS OF PORTIONS OF ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES WHERE MOISTURE WILL LINGER LONGER AND THE FETCH ACROSS LAKE SUPERIOR WILL BE BETTER AND NW WINDS WILL NOT CHANGE DIRECTIONS MUCH THROUGH THE EVENT. OVER THESE ERN AREAS...THE NAM SHOWS STORM TOTAL QPF /WHICH SHOULD BE ALMOST ALL SNOW/ OF JUST UNDER 0.80 INCHES...WHICH MAY BE A BIT ON THE HIGH SIDE BUT CAN NOT BE RULED OUT. OVERALL...THINK 6-10 INCHES /WITH SOME POTENTIAL FOR UP TO A FOOT/ TOTAL SNOWFALL SEEMS REASONABLE FOR THE ERN AREAS. LOWEST CONFIDENCE IS OVER THE NRN HURON MOUNTAINS IN NW MARQUETTE AND NE BARAGA COUNTIES...AS THIS AREA IS ALWAYS HARD TO FORECAST IN NW WINDS...BUT WOULD THINK 3-5 INCHES STORM TOTAL SNOW IS REASONABLE. THE HIGHER TERRAIN OF WRN UPPER MI FROM IWD TO CMX AND COPPER HARBOR SHOULD SEE 4-8 INCHES STORM TOTAL SNOW /HIGHEST OVER PORTION OF NRN HOUGHTON COUNTY AND WRN ONTONAGON/NRN GOGEBIC COUNTIES/...BUT WITH MORE UNCERTAINTY THAT THE ERN CWA AND MORE HIGHER POSSIBILITIES OF HIGHER OR LOWER AMOUNTS. NCENTRAL PARTS OF THE CWA /GENERALLY IN THE MARQUETTE-NEGAUNEE AREA/ LOOK TO SEE 1-3 INCHES OF SNOW THROUGH THE ENTIRE PERIOD. SCENTRAL PORTIONS OF THE CWA SHOULD SEE LITTLE TO NO SNOW. HEADLINES FOR THIS EVENT ARE SOMEWHAT TRICKY IN THAT TRADITIONAL SNOWFALL AMOUNT BASED CRITERIA WILL NEED TO BE RELAXED GIVEN A VARIETY OF PREVIOUSLY DISCUSSED SOCIETAL IMPACTS AND OTHER CONTRIBUTING FACTORS /SUCH AS GUSTY WINDS/. GIVEN HIGHER CONFIDENCE OVER THE ERN CWA /ALGER...LUCE AND NRN SCHOOLCRAFT COUNTIES/ DECIDED TO ISSUE A WINTER STORM WATCH FOR THESE AREAS. ELSEWHERE ALONG THE LAKE SUPERIOR SHORE...ISSUED AN SPS HIGHLIGHTING POOR TRAVEL CONDITIONS SINCE IT IS TOO FAR OUT FOR AN ADVISORY. NEXT SYSTEM OF INTEREST MOVES OVERHEAD ON SAT NIGHT INTO EARLY SUN AS A CLIPPER SYSTEM PUSHES THROUGH. BEST MOISTURE IS CO-LOCATED WITH UPPER SUPPORT IN LEFT EXIT REGION OF UPPER JET OVER NRN PORTIONS OF THE AREA. INCREASED CONSENSUS GUIDANCE TO MID RANGE CHANCE POPS. AT THIS TIME A COUPLE OF INCHES OF SNOW APPEARS POSSIBLE...MAINLY IN THE HIGHER TERRAIN OVER THE NRN CWA. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 257 AM EST THU NOV 22 2012 AT KSAW...IFR VIS THAT HAS DEVELOPED UNDER RADIATIONAL COOLING WILL LIKELY PERSIST THRU THE NIGHT. IFR CIGS MAY ALSO SET IN AT SOME POINT DURING THE NIGHT. VFR CONDITIONS SHOULD PREVAIL AT KIWD/KCMX OVERNIGHT AS DOWNSLOPE NATURE OF SSW FLOW SHOULD LIMIT THE POTENTIAL FOR LOW CLOUDS/FOG. LLWS IS EXPECTED AS SSW WINDS ABOVE RADIATION INVERSION HAVE INCREASED TO 30KT PER KMQT VAD WIND PROFILE. WINDS SHOULD CONTINUE TO INCREASE A LITTLE MORE DURING THE NIGHT. DAYTIME HEATING/MIXING SHOULD END LLWS/DISSIPATE ANY LOW CLOUDS/FOG BY LATE MORNING. ARRIVAL OF COLD FRONT LATE IN THE DAY WILL LIKELY BRING LOW MVFR CIGS TO KIWD/KCMX AFTER 20Z. RA/SN CHANGING TO SN WILL DEVELOP AT KIWD/KCMX IN THE EVENING AND SPREAD TO KSAW LATE EVENING. A PERIOD OF AT LEAST MDT SNOW/LIFR CONDITIONS IS ANTICIPATED AT KCMX MID TO LATE EVENING AS SECONDARY COLD FRONT BOOSTS LAKE ENHANCEMENT UNDER STRONG CAA. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 PM EST WED NOV 21 2012 EXPECT S WINDS UP TO 20 KTS THRU THIS EVENING TO INCREASE UP TO 25 KTS LATE TONIGHT AND THU UNDER TIGHTENING PRES GRADIENT AHEAD OF COLD FRONT ASSOCIATED WITH POWERFUL DISTURBANCE MOVING ACROSS THE NORTHERN CONUS. ONCE THE COLD FRONT MOVES WEST TO EAST THU AFTERNOON AND NIGHT...EXPECT A SHARP WIND SHIFT TO THE NW. AS THE PRES GRADIENT TIGHTENS CONSIDERABLY AND MUCH COLDER AIR MOVES OVER THE UPPER LAKES...EXPECT A HI END GALE EVENT EXCEPT OVER THE FAR W WITH THE COLDER AIR ENHANCING THE MIXING OF STRONGER WINDS ALOFT TO THE LAKE SURFACE. GIVEN THE CONSISTENT FORECAST TIMING AND STRENGTH OF THIS EVENT...OPTED TO UPGRADE GOING GALE WATCHES TO WARNINGS FOR THE LATE THU NIGHT INTO FRI NIGHT PERIOD. SOME STORM FORCE WIND GUSTS WILL ALSO BE POSSIBLE ON FRI...ESPECIALLY OVER THE E HALF OF THE LAKE. THE APPROACH OF A HI PRES RIDGE LATE FRI NIGHT WILL CAUSE THE GALES TO DIMINISH W-E THEN. ANOTHER LO PRES TROF WILL IMPACT THE UPPER GREAT LAKES OVER THE WEEKEND...BUT A WEAKER PRES GRADIENT WILL LIKELY HOLDS WINDS TO NO HIER THAN 25 KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE FRIDAY NIGHT FOR MIZ006-007-085. LAKE SUPERIOR... GALE WARNING FROM 1 AM FRIDAY TO 1 AM EST SATURDAY FOR LSZ264>267. GALE WARNING FROM 1 AM TO 7 PM EST FRIDAY FOR LSZ243>245-248>251- 263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...TITUS AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
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
AREA FORECAST DISCUSSION
NWS BILLINGS MT
922 AM MST THU NOV 22 2012 .SHORT TERM...VALID FOR TDY AND FRI... CANADIAN COLD FRONT AND ASSOCIATED PRESSURE RISES SURGING MUCH FURTHER WEST THAN PREVIOUSLY THOUGHT. COLD AIR HAS PUSHED THROUGH JUDITH GAP WHERE TEMP MADE AN 11 DEGREE DROP FROM 31F TO 20F LAST HOUR. STRONG COLD ADVECTION FURTHER EAST IS NOT QUITE TO MILES CITY AND BAKER BUT WILL BE BEFORE MIDDAY. WITH TEMPS LARGELY IN THE TEENS UPSTREAM...EXPECT A FAIRLY DRAMATIC TEMPERATURE DROP ESPECIALLY IN OUR EAST. PER LOCATION OF UPSTREAM PRESSURE RISES...THINK THIS FROPA WILL HAVE SOME IMPACT AT BILLINGS AS WELL. FOR BILLINGS...EXPECT A SHIFT TO NORTH THEN EVENTUALLY NORTHEAST WINDS THIS AFTERNOON...AND AN ASSOCIATED TEMPERATURE DROP TO MAYBE THE LOW 30S/UPPER 20S AFTER A MIDDAY HIGH IN THE LOW 40S. AS FOR PCPN...TROWAL WRAPPING SOUTHWARD THROUGH NORTHERN MT WILL BRING SOME LIGHT SNOW SHOWERS TO OUR EASTERN PARTS...WITH STRONGEST ASCENT PER THE RAP EXPECTED TO BE FROM ABOUT 18-23Z. GIVEN MOISTENING OF DENDRITIC LAYER WHICH WILL FALL TO THE SFC...COULD BE A DUSTING IN PLACES MAINLY EAST OF HYSHAM AND LAME DEER. AREAS FROM FORSYTH TO BAKER HAVE ALSO EXPERIENCED SOME STRATUS THIS MORNING PER ADVECTION FROM THE NW. WEB CAMS HAVE SHOWN SOME VSBY REDUCTIONS OVER THE HILLS OUT THAT WAY. NW WINDS WILL BE QUITE GUSTY THIS AFTERNOON ESPECIALLY ACROSS OUR EAST...WITH CORE OF STRONGEST BOUNDARY LAYER WINDS PUSHING INTO THE DAKOTAS. LOOKS LIKE WIDESPREAD 35-45 MPH GUSTS EAST OF BILLINGS. CURRENT FORECAST HAS COVERED WELL. ANY -SHSN ACTIVITY SHOULD BE OVER BY LATE AFTERNOON...LEADING TO A DRY NIGHT TONIGHT WITH MUCH COLDER TEMPS/LIGHTER WINDS AS SFC RIDGE BUILDS IN. WILL HAVE TO SEE HOW FAR WEST COLD ADVECTION PUSHES DURING THE DAY AS THIS WILL IMPACT LOWS TONIGHT AND LOCATION OF LEE SIDE TROF WHEN IT DEVELOPS. JKL .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... EXTENDED MODELS IN OVERALL AGREEMENT WITH LARGE-SCALE FEATURES BUT DIFFER IN SOME PARTICULAR DETAILS. A STRONG COLD FRONT WILL SWEEP ACROSS THE FORECAST AREA LATE SATURDAY AFTERNOON INTO SATURDAY EVENING. AHEAD OF THE FRONT...EXPECT GUSTY SOUTHWEST TO WEST WINDS ALONG WITH DOWNSLOPE WARMING...ALTHOUGH TEMPERATURES WILL NOT WARM TOO MUCH. HIGH TEMPERATURES WILL BE TRICKY DEPENDING ON TIMING OF THE FRONT BUT MOST PLACES SHOULD RISE INTO THE UPPER 30S TO LOWER 40S. THE FRONT WILL BRING RAIN AND SNOW SHOWERS WITH THE PRECIP CHANGING TO ALL SNOW BY LATE SATURDAY NIGHT. AN EASTERLY UPSLOPE FLOW AND FRONTOGENESIS BAND DEVELOP LATE SATURDAY NIGHT THROUGH SUNDAY ACROSS MOST OF THE FORECAST AREA BUT ESPECIALLY ALONG THE EASTERN SLOPES OF THE BEARTOOTH/ABSAROKA MOUNTAINS TO THE BIG HORNS. THE AREA SHOULD SEE WIDESPREAD SNOW LATE SATURDAY NIGHT THROUGH THE ENTIRE DAY SUNDAY BEFORE TAPERING OFF BY MONDAY MORNING. AT THIS TIME...ADVISORY TYPE ACCUMULATIONS LOOK LIKELY FOR MANY LOCATIONS. TEMPERATURES ARE NOT VERY COLD WITH THIS SYSTEM RESULTING IN SNOW RATIOS AROUND 10:1 FOR MOST OF THE EVENT WITH SOME HIGHER RATIOS SUNDAY NIGHT. THE SYSTEM LOOKS TO BE DIFFERENT FROM WHAT OUR AREA USUALLY SEES WITH A COLD FRONT AND SNOW IN THAT TEMPERATURES ARE NOT EXPECTED TO GET VERY COLD LIKE USUALLY IS THE CASE WITH A FRONT DROPPING OUT OF CANADA THIS TIME OF YEAR. TEMPERATURES MONDAY ARE STILL EXPECTED TO REBOUND INTO THE UPPER 20S TO LOWER 30S AFTER MORNING LOWS IN THE TEENS. UNSETTLED NORTHWEST FLOW ALOFT LOOKS TO BE OVER THE FORECAST AREA TUESDAY INTO WEDNESDAY WITH A POSSIBLE RIDGE AND WARMER TEMPERATURES BUT LATE NEXT WEEK. HOOLEY && .AVIATION... REINFORCING COLD FRONT LOCATED FROM LEWISTOWN TO SOUTH OF MILES CITY AND BAKER WILL CONTINUE TO SLIDE SOUTH TODAY. FRONT WILL LIKELY BACK TO A POSITION JUST EAST OF LIVINGSTON AND ALONG THE BEARTOOTH FRONT BEFORE BECOMING STATIONARY THIS EVENING. LOW LEVEL MOISTURE WILL BRING WIDESPREAD MVFR TO OCCASIONAL IFR CEILINGS BEHIND THIS FRONT...ALONG WITH SCATTERED SNOW SHOWERS EAST OF A ROUNDUP TO HARDIN LINE. TO THE WEST OF THE FRONT WEST TO NORTHWEST WINDS WILL BE GUST TO AROUND 30 KTS AT TIMES...WHILE A NORTH TO NORTHEAST WIND WILL FILL IN BEHIND THE FRONT. FOR KMLS TAF LOCATION...IFR VISIBILITY FOG HAS DEVELOPED BEHIND THE RECENT COLD FRONTAL PASSAGE. EXPECT THIS FOG TO LIFT AS SCATTERED SNOW SHOWERS MOVE INTO THE AREA BY MID DAY. HOWEVER AN MVFR TO IFR STRATUS CEILING WILL PERSIST...LIKELY THROUGH LATE TONIGHT. FOR KBIL TAF LOCATION...COLD FRONT WAS 50NM TO THE NORTH OF THE AIRPORT AT 16Z. WEST WINDS GUSTING TO 30 KTS WILL PERSIST UNTIL FRONTAL PASSAGE...AROUND 19Z. ONCE THE FRONT MOVES THROUGH EXPECT WINDS TO TURN NORTHEASTERLY AND MVFR CEILING TO DEVELOP. MVFR CEILINGS WILL PERSIST THROUGH LATE TONIGHT. CHAMBERS && .PRELIMINARY POINT TEMP/POPS... TDY FRI SAT SUN MON TUE WED ------------------------------------------------------- BIL 041 022/051 037/051 031/034 020/031 016/035 021/040 0/N 00/B 04/W 67/S 73/J 12/J 32/W LVM 038 022/050 038/046 028/033 018/031 014/033 022/039 0/N 00/N 06/W 78/S 74/J 12/J 32/W HDN 043 017/051 030/052 030/036 020/032 014/035 020/041 1/N 00/B 04/W 67/S 73/J 11/B 22/W MLS 032 011/040 028/049 028/030 017/028 014/031 020/036 3/J 00/B 02/W 46/S 42/J 11/B 21/B 4BQ 038 011/044 029/052 029/035 018/029 014/033 020/039 3/J 00/U 02/W 67/S 63/J 11/B 21/B BHK 032 007/036 026/047 025/027 015/026 013/029 018/036 3/J 00/U 00/B 36/S 41/E 11/B 11/B SHR 038 015/049 028/052 027/033 018/029 011/032 018/041 2/J 00/U 03/W 67/S 73/J 11/B 22/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
238 PM CST THU NOV 22 2012 .DISCUSSION... THE ARCTIC FRONT APPEARS TO BE ENTERING NWRN SD THIS AFTN. THE LATEST NAM AND RAP SOLNS SHOW THIS FRONT DROPPING THRU NCNTL NEB THIS EVENING WITH WINDS ALOFT INCREASING TO 65KT AT 700MB...50KT AT 850MB AND 25 TO 30KT AT 500M AGL. SO SFC WINDS COULD RUN 25 TO 30 MPH ALONG THE FRONT AND POTENTIAL GUSTS TO 45 MPH. THUS THE WIND ADVISORY WILL BE EXTENDED ACROSS PARTS OF NCNTL NEB TONIGHT IN ANTICIPATION OF THIS FRONTAL PASSAGE. ARCTIC HIGH PRESSURE SLIDES THROUGH THE MISSOURI BASIN FRIDAY AND INTO THE MID SOUTH BY SATURDAY MORNING. WITH THE ARCTIC HIGH BUILDING THROUGH THE MISSOURI BASIN...THE COLD CORE NEVER REACHES FAR WESTERN NEB SO A QUICK TEMPERATURE REBOUND CAN OCCUR SATURDAY AS NEW LOW PRESSURE TRACKS THROUGH SRN SASKATCHEWAN AND MANITOBA TURNING TO THE WEST ACROSS THE FCST AREA. THIS LOW THEN DROPS ANOTHER ARCTIC FRONT INTO SOUTH DAKOTA SUNDAY WITH NW FLOW ALOFT MAINTAINING A BAROCLINIC ZONE AND WEAK MID LEVEL FRONTOGENESIS DEVELOPING. THE SFC FRONT IS FCST TO DROP THROUGH NRN NEB SUNDAY AFTERNOON AND THE MODELS SUGGEST SUFFICIENT LOW LEVEL MOISTURE FOR A CHANCE OF LIGHT RAIN OR SNOW SUNDAY AFTERNOON CHANGING TO SNOW SUNDAY NIGHT AND ENDING MONDAY MORNING. LIGHT ACCUMULATIONS WOULD DEVELOP GIVEN THE FLEETING NATURE OF THE MID LEVEL FRONT...THE OPEN WAVE AT 700MB SHOWN BY ALL MODELS AND 250 MB JET MAX MOVING THROUGH SRN NEB. WEAK ARCTIC HIGH PRESSURE MOVES QUICKLY THROUGH THE FCST AREA TUESDAY FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM TRACKING ALONG THE CANADIAN BORDER WEDNESDAY. THIS SYSTEM WILL PULL ANOTHER FAST MOVING ARCTIC HIGH PRESSURE SYSTEM INTO THE FCST AREA FOR NEXT THURSDAY. SAVE FOR ISOLATED FLURRIES WITH THE ARCTIC FRONT TONIGHT AND LIGHT SNOW POSSIBLE LATE SUNDAY AND MONDAY MORNING...THE FORECAST IS DRY. TEMPERATURES RANGE FROM 30S AND 40S NORTHEAST TO 40S AND 50S SOUTHWEST. && .AVIATION... WINDS WILL CONTINUE TO BE THE PRIMARY AVIATION CONCERN THROUGH FRIDAY. STRONG NORTHWEST TO NORTHERLY WINDS WILL CONTINUE THROUGH THEN AFTERNOON AS A TIGHT PRESSURE GRADIENT AND GOOD MIXING OCCURS ACROSS THE AREA. WINDS WILL DIMINISH FOR A PERIOD THIS EVENING... THEN EXPECT ANOTHER INCREASE IN WINDS LATER IN THE EVENING AND INTO THE OVERNIGHT PERIODS /ROUGHLY 03Z TO 08Z/ AS A FRONT MOVES THROUGH THE REGION FROM NORTH TO SOUTH. THE STRONGEST WINDS ARE EXPECTED OVER NORTH CENTRAL NEBRASKA...INCLUDING THE KVTN TAF SITE. WINDS IN THESE AREAS COULD AGAIN GUST UP TO 45 MPH. WINDS WILL DIMINISH BY MORNING WITH BENIGN AVIATION WEATHER CONDITIONS FOR FRIDAY. && .FIRE WEATHER... OBSERVATIONS ACROSS WESTERN NEBRASKA HAVE GOTTEN NEAR RED FLAG CRITERIA THIS AFTERNOON AS WINDS GUSTED BETWEEN 35 AND 45 MPH...WHILE DEW POINTS DROPPING INTO THE SINGLE DIGITS AND LOW TEENS LOWERED RELATIVE HUMIDITY INTO THE UPPER TEENS AND LOW 20S. HOWEVER...COLDER AIR WAS IN PLACE...WITH TEMPERATURES ONLY IN THE MID AND UPPER 40S. ALTHOUGH CONDITIONS ARE CLOSE...AND MAY EVEN HIT CRITERIA IN LOCALIZED SPOTS FOR A FEW HOURS...THESE LOWER TEMPERATURES WILL KEEP FROM ISSUING A SHORT FUSED RED FLAG WARNING FOR THE REMAINDER OF THE AFTERNOON. THAT BEING SAID...WITH THE STRONG WINDS...ANY FIRES WILL STILL HAVE THE POTENTIAL TO SPREAD RAPIDLY THIS AFTERNOON. BEYOND TODAY...SATURDAY COULD SEE ELEVATED FIRE WEATHER CONDITIONS WITH RELATIVE HUMIDITY DROPPING INTO THE UPPER TEENS AND 20S...HOWEVER WINDS ARE ONLY FORECAST AT 15 TO 20 MPH AT THE PEAK. OTHERWISE THE REMAINDER OF THE NEXT 7 DAYS SHOULD BE QUIET FOR FIRE CONCERNS. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 6 PM CST /5 PM MST/ THIS EVENING FOR NEZ004-022>024-035>037-056>059-069>071-094. WIND ADVISORY UNTIL 4 AM CST FRIDAY FOR NEZ005>010-025>029-038. && $$ SHORT TERM/EXTENDED...CDC AVIATION...BROOKS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
433 AM EST THU NOV 22 2012 .SYNOPSIS... HIGH PRESSURE WILL BRING ANOTHER MILD AND SUNNY DAY TO CENTRAL NEW YORK AND NORTHEAST PENNSYLVANIA. A COLD FRONT WILL PASS THE REGION LATE FRIDAY AFTERNOON AND EVENING WITH SHOWERS. COLD AIR BEHIND THIS FRONT WILL ALLOW LAKE EFFECT SNOWS TO DEVELOP OVER PORTIONS OF CENTRAL NEW YORK LATE FRIDAY NIGHT...WHICH WILL PERSIST INTO SATURDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... SFC HI PRES RDG XTNDG FROM NEW ENGLAND INTO THE MID ATLC STATES WILL BRING ANOTHER VERY NICE DAY TO THE FCST AREA...WITH MOSTLY SUNNY SKIES AND TEMPS WELL ABV NORMAL. GIVEN FCST 925 TEMPS OF +8 IT LOOKS LIKE WE`LL SEE MAXES FLIRTING WITH 60 IF NOT THE LOWER 60S ACRS THE CNTRL SRN TIER AND FINGER LAKES...M/U 50S ELSEWHERE. FAIR WX CONTNIUE TNGT WITH SRLY FLOW INCRSNG. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... WE`LL SEE SOME SUNSHINE AHEAD OF THE FNT ON FRI AND IT APPEARS WE`LL HAVE MAXES WELL INTO THE 50S ONCE AGAIN. CDFNT WILL PASS LATE FRI AFTN/FRI EVNG WITH A BAND OF -SHRA. COLDER AIR WORKS IN BEHIND THE FNT FRI NGT INTO SAT. ATTM IT APPEARS THAT FLOW WILL REMAIN WSW TIL ARND 06Z WITH FLOW BCMG MORE NWLY BY 12Z SAT. THE NW FLOW PERSISTS INTO SAT NGT. CYCLONIC FLOW ALOFT...GOOD LOW LVL INSTAB...DENDRITIC SNOW GROWTH AND FAIRLY HI INVERSION LVL SHOWN IN IN THE PROFILES...WITH SOME HINT OF PSBL HURON BAY CONNECTION TO ONTARIO ACTIVITY ON SAT. HOWEVER...SOME SUGGESTION THAT THE SYNOPTIC AIR MASS MAY BE ON THE DRY SIDE (EURO SHOWS TD`S DROPPING INTO THE L/M TEENS DURING THIS TIME FRAME). IN ANY EVENT...POTNL APPEARS TO BE THERE FOR ACCUMULATIONS....PRBLY IN THE ADVISORY RNG...SPCLY ACRS THE FAVORED TRRN IN 300-320 FLOW SAT INTO SAT NGT. WILL CONTINUE TO MENTION IN THE HWO. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... 345 AM UPDATE... FORECAST ONLY ADJUSTED SLIGHTLY AS NEEDED FOR COLLABORATION PURPOSES AND TO ACCOUNT FOR LATEST MODEL TRENDS. THE GENERAL IDEA REMAINS THE SAME. 850MB RIDGE NEVER REALLY REACHES THE AREA...IT ACTUALLY FLATTENS TO OBLIVION IN RESPONSE TO PASSING WAVE ON SUNDAY. WAVE EVENTUALLY YIELDS WARM AIR ADVECTION ALOFT...BUT 850MB TEMPERATURES REMAIN COLD ENOUGH FOR AT LEAST A MARGINAL CONTINUED LAKE RESPONSE. WARM FRONT MAY STRUGGLE TO FILL THE DRY LAYER BETWEEN HIGH LEVEL MOISTURE ASSOCIATED WITH WARM FRONT ALOFT...AND LAKE MOISTURE IN THE LOWER LEVELS. REGARDLESS THOUGH...LAKE MOISTURE BY ITSELF MAY BE ENOUGH FOR AT LEAST SCATTERED SNOW SHOWERS TO CONTINUE INTO A WAYS INTO SUNDAY FOR CENTRAL NY WHILE SHIFTING NORTHWARD /BACKING WIND/. MODELS CONTINUE THEIR CONFUSION FOR HOW TO HANDLE LOW PRESSURE SYSTEM MON NIGHT THROUGH TUE NIGHT PERIOD. ECMWF KEEPS US COLDER YET IS SO FAR SOUTH WITH TRACK OF LOW /WHICH IS ALSO WEAKER/...THAT DEPICTED PRECIPITATION SHIELD DOES NOT EVEN MAKE IT INTO OUR AREA DUE TO STRENGTH OF SURFACE HIGH OVER EASTERN CANADA. MEANWHILE GFS IS BETTER PHASED AND AMPLIFIED...AND THUS DEVELOPS STRONGER SURFACE LOW THAT TRACKS UP OHIO VALLEY AND THROUGH THE REGION. SOME WARMER AIR GETS INVOLVED IN THE GFS SOLUTION...WHICH MAKES PRECIPITATION TYPE COMPLICATED YET EVENTUALLY TRANSITIONING TO ALL SNOW SHOWERS IN THE WAKE OF THE POTENTIAL SYSTEM. WITH MUCH UNCERTAINTY...KEEPING POPS ONLY IN CHANCE RANGE SEEMS BEST AT THIS TIME. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... 06Z UPDATE... VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR. OUTLOOK... FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE. FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN. SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS. SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN. MON...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ LONG TERM...MDP/PVN AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
410 AM EST THU NOV 22 2012 .SYNOPSIS... WARM ABOVE AVERAGE TEMPERATURES WILL PREVAIL ACROSS THE REGION ON THANKSGIVING DAY WITH MANY LOCATIONS EASILY WARMING INTO THE MIDDLE TO UPPER 50S FOR DAYTIME HIGHS. ABOVE NORMAL TEMPERATURES WILL QUICKLY COME TO AN END BY FRIDAY AS A STRONG COLD FRONT SWINGS THROUGH THE REGION. COLD AIR WILL RAPIDLY OVERSPREAD THE REGION FRIDAY NIGHT AND SATURDAY WITH REDEVELOPING LAKE EFFECT SNOWS EXPECTED OVER THE UPCOMING WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030 PM UPDATE...CURRENT FORECAST REMAINS IN GOOD SHAPE, JUST LOWERED OVERNIGHT LOWS BY 2-4 DEGREES AS WEAK BOUNDARY LAYER FLOW WILL PERSIST UNTIL DAYBREAK EVEN ALONG THE LAKE PLAIN. WITH DEW POINTS CONTINUING TO FALL IN TANDEM WITH SFC TEMPS, DENSE FOG FORMATION IS NOT EXPECTED. 530 PM UPDATE...CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS TO FALL QUICKLY LATE THIS AFTERNOON. AT PENN YAN AND ELMIRA TEMPS FELL 10 AND 13 DEGREES RESPECTIVELY DURING THE PAST HOUR. ADJUSTED TEMP GRIDS TO REFLECT THIS OTHERWISE FORECAST IN GOOD SHAPE WITH NO OTHER CHANGES. PREVIOUS DISC... VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE REGION THIS AFTERNOON AS SFC RIDGING ASSOCIATED WITH CANADIAN MARITIMES HIGH PRESSURE CONTINUES TO EXTEND SOUTHWEST OVER OUR AREA. WITH ABUNDANT SUNSHINE PREVAILING OVERHEAD...TEMPS HAVE WARMED INTO THE LOWER 50S ACROSS MUCH OF THE AREA WHICH IS ANYWHERE BETWEEN 5-10 DEGREES ABOVE NORMAL. WITH A DRY AIRMASS IN PLACE...TEMPS WILL FALL OFF QUICKLY THIS EVENING WITH OVERNIGHT LOWS EXPECTED TO REACH THE LOWER TO MIDDLE 30S. THE ONLY CONCERN WITH THE GOING FCST OVERNIGHT WILL BE POSSIBLE FOG FORMATION TOWARDS MORNING. UPSTREAM OBSERVATIONS THIS MORNING SHOWED AN EXPANSIVE AREA OF FOG ACROSS THE UPPER MIDWEST WHERE VISIBILITIES WERE NEAR ZERO ACROSS THE GREATER CHICAGO AREA FOR HRS. THIS MOIST LOW-LEVEL AIRMASS WILL ADVANCE EAST OVERNIGHT WHERE IT WILL ENCOUNTER MORE AND MORE DRY AIR WITH FURTHER EASTWARD PROGRESS. FOR NOW...STATISTICAL GUIDANCE MAKING NO SUGGESTION OF ANY FOG FORMATION ACROSS OUR AREA HOWEVER EVENING SHIFT WILL HAVE TO MONITOR TRENDS ACCORDINGLY. UNSEASONABLY WARM TEMPS TO CONTINUE RIGHT THROUGH THANKSGIVING DAY WHERE 925-MB THERMAL RIDGING CHARACTERIZED BY TEMPS APPROACHING 9C WILL SUPPORT AFTERNOON HIGH TEMPS REACHING THE MIDDLE TO UPPER 50S ACROSS MANY AREAS. THAT SAID...HAVE ELECTED TO INCREASE TEMPS A FEW DEGREES WITH UPPER 50S NOW BEING FORECAST ACROSS THE LAKE PLAIN WHERE DOWNSLOPE COMPRESSIONAL WARMING MAY ALLOW TEMPS TO APPROACH 60. FROM A CLIMATOLOGICAL STANDPOINT...IF SYR WERE TO HIT 60 ON THANKSGIVING DAY...IT WILL BE THE FIRST TIME SINCE 2004 WHEN THE MERCURY CLIMBED TO A BALMY 63 DEGREES. DRY CONDITIONS TO CONTINUE RIGHT THROUGH THANKSGIVING NIGHT WITH OVERNIGHT LOWS EXPECTED TO FALL INTO THE MIDDLE TO UPPER 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... BIG CHANGES ON THE WAY BEGINNING FRI AS A WELL ADVERTISED COLD FRONT SWINGS THROUGH THE AREA. PRECIP ALONG AND AHEAD OF THE FRONT WILL BEGIN WORKING THROUGH THE WESTERN ZONES DURING THE LATE MORNING BEFORE CLEARING THE ENTIRE CWA BY EARLY EVENING. WITH THE FRONT MOVING THROUGH RAPIDLY...EXPECT PRECIP TOTALS TO GENERALLY RANGE BELOW TWO TENTHS OF AN INCH. FOR AREAS MAINLY ALONG AND WEST OF I-81...TEMPS WILL FALL RAPIDLY THROUGH THE MID/LATE AFTERNOON AS STRONG COLD AIR ADVECTION OVERSPREADS THE REGION IN THE FRONT/S WAKE. BIG STORY HOWEVER WILL BE THE RAPID COOL DOWN EXPECTED FOLLOWING FROPA AND THE REDEVELOPMENT OF LAKE EFFECT SNOW BEGINNING EARLY SAT MORNING. INITIAL WIND DIRECTION FOLLOWING FROPA WILL FOLLOW A WESTERLY TRAJECTORY WHICH WILL FAVOR THE SOUTHERN TUG HILL THROUGH ROUGHLY 12Z ON SAT. FOLLOWING THIS...BOTH NAM AND GFS FCST MODELS SHOW A SFC TROUGH DROPPING SOUTH IN CYCLONIC FLOW WHICH WILL ALLOW WINDS TO SHIFT AROUND TO THE NORTHWEST THROUGH THE MORNING. AS THIS OCCURS...850-MB TEMPS WILL CONTINUE TO COOL WITH VALUES REACHING NEAR -13C BY 00Z SUN. INSPECTION OF SEVERAL GFS AND NAM BUFKIT SOUNDINGS REVEALS AN INCREASINGLY FAVORABLE ENVIRONMENT FOR LAKE EFFECT SNOWS THROUGH THE DAY ON SAT WITH GOOD SATURATION THROUGH THE FAVORABLE DENDRITIC SNOW GROWTH REGION. THAT SAID...HAVE DRAWN HIGHEST POPS FROM SOUTHERN ONEIDA COUNTY WEST THROUGH THE CENTRAL FINGER LAKES TO INCLUDE THE ITHACA AND SYRACUSE METRO AREAS. FROM THIS VANTAGE POINT...SEVERAL INCHES OF FRESH LAKE EFFECT SNOWFALL WILL BE POSSIBLE AS TEMPS STRUGGLE TO REACH THE MID 30S FOR DAYTIME HIGHS. FOR NOW...IT LOOKS LIKE LAKE SNOWS WILL CONTINUE RIGHT THROUGH SAT NGT WHICH WILL OBVIOUSLY JUST ADD TO SNOW TOTALS. WOULD NOT BE SURPRISED IF ADVISORIES EVENTUALLY GET POSTED HOWEVER ITS MUCH TO EARLY FOR THIS NOW. IN ANY EVENT...WILL HIGHLIGHT SNOW ACCUMULATION POTENTIAL IN THE HWO TO INCREASE AWARENESS FOR HOLIDAY WEEKEND TRAVELERS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 345 AM UPDATE... FORECAST ONLY ADJUSTED SLIGHTLY AS NEEDED FOR COLLABORATION PURPOSES AND TO ACCOUNT FOR LATEST MODEL TRENDS. THE GENERAL IDEA REMAINS THE SAME. 850MB RIDGE NEVER REALLY REACHES THE AREA...IT ACTUALLY FLATTENS TO OBLIVION IN RESPONSE TO PASSING WAVE ON SUNDAY. WAVE EVENTUALLY YIELDS WARM AIR ADVECTION ALOFT...BUT 850MB TEMPERATURES REMAIN COLD ENOUGH FOR AT LEAST A MARGINAL CONTINUED LAKE RESPONSE. WARM FRONT MAY STRUGGLE TO FILL THE DRY LAYER BETWEEN HIGH LEVEL MOISTURE ASSOCIATED WITH WARM FRONT ALOFT...AND LAKE MOISTURE IN THE LOWER LEVELS. REGARDLESS THOUGH...LAKE MOISTURE BY ITSELF MAY BE ENOUGH FOR AT LEAST SCATTERED SNOW SHOWERS TO CONTINUE INTO A WAYS INTO SUNDAY FOR CENTRAL NY WHILE SHIFTING NORTHWARD /BACKING WIND/. MODELS CONTINUE THEIR CONFUSION FOR HOW TO HANDLE LOW PRESSURE SYSTEM MON NIGHT THROUGH TUE NIGHT PERIOD. ECMWF KEEPS US COLDER YET IS SO FAR SOUTH WITH TRACK OF LOW /WHICH IS ALSO WEAKER/...THAT DEPICTED PRECIPITATION SHIELD DOES NOT EVEN MAKE IT INTO OUR AREA DUE TO STRENGTH OF SURFACE HIGH OVER EASTERN CANADA. MEANWHILE GFS IS BETTER PHASED AND AMPLIFIED...AND THUS DEVELOPS STRONGER SURFACE LOW THAT TRACKS UP OHIO VALLEY AND THROUGH THE REGION. SOME WARMER AIR GETS INVOLVED IN THE GFS SOLUTION...WHICH MAKES PRECIPITATION TYPE COMPLICATED YET EVENTUALLY TRANSITIONING TO ALL SNOW SHOWERS IN THE WAKE OF THE POTENTIAL SYSTEM. WITH MUCH UNCERTAINTY...KEEPING POPS ONLY IN CHANCE RANGE SEEMS BEST AT THIS TIME. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... 06Z UPDATE... VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR. OUTLOOK... FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE. FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN. SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS. SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN. MON...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG NEAR TERM...CMG/RRM SHORT TERM...CMG LONG TERM...MDP AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 AM EST THU NOV 22 2012 .SYNOPSIS... WARM ABOVE AVERAGE TEMPERATURES WILL PREVAIL ACROSS THE REGION ON THANKSGIVING DAY WITH MANY LOCATIONS EASILY WARMING INTO THE MIDDLE TO UPPER 50S FOR DAYTIME HIGHS. ABOVE NORMAL TEMPERATURES WILL QUICKLY COME TO AN END BY FRIDAY AS A STRONG COLD FRONT SWINGS THROUGH THE REGION. COLD AIR WILL RAPIDLY OVERSPREAD THE REGION FRIDAY NIGHT AND SATURDAY WITH REDEVELOPING LAKE EFFECT SNOWS EXPECTED OVER THE UPCOMING WEEKEND. && .NEAR TERM /THROUGH TODAY/... 1030 PM UPDATE...CURRENT FORECAST REMAINS IN GOOD SHAPE, JUST LOWERED OVERNIGHT LOWS BY 2-4 DEGREES AS WEAK BOUNDARY LAYER FLOW WILL PERSIST UNTIL DAYBREAK EVEN ALONG THE LAKE PLAIN. WITH DEW POINTS CONTINUING TO FALL IN TANDEM WITH SFC TEMPS, DENSE FOG FORMATION IS NOT EXPECTED. 530 PM UPDATE...CLEAR SKIES AND LIGHT WINDS HAVE ALLOWED TEMPS TO FALL QUICKLY LATE THIS AFTERNOON. AT PENN YAN AND ELMIRA TEMPS FELL 10 AND 13 DEGREES RESPECTIVELY DURING THE PAST HOUR. ADJUSTED TEMP GRIDS TO REFLECT THIS OTHERWISE FORECAST IN GOOD SHAPE WITH NO OTHER CHANGES. PREVIOUS DISC... VISIBLE SATELLITE IMAGERY SHOWING MOSTLY CLEAR SKIES ACROSS THE REGION THIS AFTERNOON AS SFC RIDGING ASSOCIATED WITH CANADIAN MARITIMES HIGH PRESSURE CONTINUES TO EXTEND SOUTHWEST OVER OUR AREA. WITH ABUNDANT SUNSHINE PREVAILING OVERHEAD...TEMPS HAVE WARMED INTO THE LOWER 50S ACROSS MUCH OF THE AREA WHICH IS ANYWHERE BETWEEN 5-10 DEGREES ABOVE NORMAL. WITH A DRY AIRMASS IN PLACE...TEMPS WILL FALL OFF QUICKLY THIS EVENING WITH OVERNIGHT LOWS EXPECTED TO REACH THE LOWER TO MIDDLE 30S. THE ONLY CONCERN WITH THE GOING FCST OVERNIGHT WILL BE POSSIBLE FOG FORMATION TOWARDS MORNING. UPSTREAM OBSERVATIONS THIS MORNING SHOWED AN EXPANSIVE AREA OF FOG ACROSS THE UPPER MIDWEST WHERE VISIBILITIES WERE NEAR ZERO ACROSS THE GREATER CHICAGO AREA FOR HRS. THIS MOIST LOW-LEVEL AIRMASS WILL ADVANCE EAST OVERNIGHT WHERE IT WILL ENCOUNTER MORE AND MORE DRY AIR WITH FURTHER EASTWARD PROGRESS. FOR NOW...STATISTICAL GUIDANCE MAKING NO SUGGESTION OF ANY FOG FORMATION ACROSS OUR AREA HOWEVER EVENING SHIFT WILL HAVE TO MONITOR TRENDS ACCORDINGLY. UNSEASONABLY WARM TEMPS TO CONTINUE RIGHT THROUGH THANKSGIVING DAY WHERE 925-MB THERMAL RIDGING CHARACTERIZED BY TEMPS APPROACHING 9C WILL SUPPORT AFTERNOON HIGH TEMPS REACHING THE MIDDLE TO UPPER 50S ACROSS MANY AREAS. THAT SAID...HAVE ELECTED TO INCREASE TEMPS A FEW DEGREES WITH UPPER 50S NOW BEING FORECAST ACROSS THE LAKE PLAIN WHERE DOWNSLOPE COMPRESSIONAL WARMING MAY ALLOW TEMPS TO APPROACH 60. FROM A CLIMATOLOGICAL STANDPOINT...IF SYR WERE TO HIT 60 ON THANKSGIVING DAY...IT WILL BE THE FIRST TIME SINCE 2004 WHEN THE MERCURY CLIMBED TO A BALMY 63 DEGREES. DRY CONDITIONS TO CONTINUE RIGHT THROUGH THANKSGIVING NIGHT WITH OVERNIGHT LOWS EXPECTED TO FALL INTO THE MIDDLE TO UPPER 30S. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... BIG CHANGES ON THE WAY BEGINNING FRI AS A WELL ADVERTISED COLD FRONT SWINGS THROUGH THE AREA. PRECIP ALONG AND AHEAD OF THE FRONT WILL BEGIN WORKING THROUGH THE WESTERN ZONES DURING THE LATE MORNING BEFORE CLEARING THE ENTIRE CWA BY EARLY EVENING. WITH THE FRONT MOVING THROUGH RAPIDLY...EXPECT PRECIP TOTALS TO GENERALLY RANGE BELOW TWO TENTHS OF AN INCH. FOR AREAS MAINLY ALONG AND WEST OF I-81...TEMPS WILL FALL RAPIDLY THROUGH THE MID/LATE AFTERNOON AS STRONG COLD AIR ADVECTION OVERSPREADS THE REGION IN THE FRONT/S WAKE. BIG STORY HOWEVER WILL BE THE RAPID COOL DOWN EXPECTED FOLLOWING FROPA AND THE REDEVELOPMENT OF LAKE EFFECT SNOW BEGINNING EARLY SAT MORNING. INITIAL WIND DIRECTION FOLLOWING FROPA WILL FOLLOW A WESTERLY TRAJECTORY WHICH WILL FAVOR THE SOUTHERN TUG HILL THROUGH ROUGHLY 12Z ON SAT. FOLLOWING THIS...BOTH NAM AND GFS FCST MODELS SHOW A SFC TROUGH DROPPING SOUTH IN CYCLONIC FLOW WHICH WILL ALLOW WINDS TO SHIFT AROUND TO THE NORTHWEST THROUGH THE MORNING. AS THIS OCCURS...850-MB TEMPS WILL CONTINUE TO COOL WITH VALUES REACHING NEAR -13C BY 00Z SUN. INSPECTION OF SEVERAL GFS AND NAM BUFKIT SOUNDINGS REVEALS AN INCREASINGLY FAVORABLE ENVIRONMENT FOR LAKE EFFECT SNOWS THROUGH THE DAY ON SAT WITH GOOD SATURATION THROUGH THE FAVORABLE DENDRITIC SNOW GROWTH REGION. THAT SAID...HAVE DRAWN HIGHEST POPS FROM SOUTHERN ONEIDA COUNTY WEST THROUGH THE CENTRAL FINGER LAKES TO INCLUDE THE ITHACA AND SYRACUSE METRO AREAS. FROM THIS VANTAGE POINT...SEVERAL INCHES OF FRESH LAKE EFFECT SNOWFALL WILL BE POSSIBLE AS TEMPS STRUGGLE TO REACH THE MID 30S FOR DAYTIME HIGHS. FOR NOW...IT LOOKS LIKE LAKE SNOWS WILL CONTINUE RIGHT THROUGH SAT NGT WHICH WILL OBVIOUSLY JUST ADD TO SNOW TOTALS. WOULD NOT BE SURPRISED IF ADVISORIES EVENTUALLY GET POSTED HOWEVER ITS MUCH TO EARLY FOR THIS NOW. IN ANY EVENT...WILL HIGHLIGHT SNOW ACCUMULATION POTENTIAL IN THE HWO TO INCREASE AWARENESS FOR HOLIDAY WEEKEND TRAVELERS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 130 PM UPDATE...CLD AIR SETS IN BHND FRONTAL PASSAGE LATE IN THE WEEK, CONTINUING THRU THE WEEKEND. H8 TEMPS DROP DOWN TO BTWN -10C TO -12C LVG MODERATE LK INSTABILITY IN ITS WAKE. FLOW ALIGNS FM 310-320 DEGREES WITH FINGER LKS AREA UNDER THE GUN FOR CONTD LK EFFECT SNOW THRU SUN AFTN. APPEARS AS THO WINDS SHIFT ARND TO THE SOUTHWEST, MVG SNOW SHOWERS NORTH OF THE CWA SUN NGT. MED RANGE MODELS AGREE ON S/WV DROPPING INTO THE INTERMOUNTAIN STATES EARLY NEXT WEEK. THIS WL INDUCE SFC LOW DVLPMNT BY 00Z TUE IN VICINITY OF MID-MS VLY. 00Z EURO IS QUICKER TO MV THIS SFC LOW NORTH TWD THE AREA BY ABOUT 12 HRS. EURO BRINGS IT UP TO THE WEST OF OUR AREA WITH RAIN OR SNOW EXPECTED DRG THE DAY ON TUESDAY. 12Z GFS SUPPRESSES THE LOW FURTHER TO THE SOUTH, THOUGH H8 TEMPS RISE ABV 0C ACRS PORTIONS OF OUR AREA. THUS HV GONE WITH CHC POPS THRU 12Z WED WITH A MIX OF RAIN OR SNOW, TOO EARLY TO SAY AT THIS POINT. TEMPS WL BE MORE TYPICAL OF VALUES EXPECTED FOR LATE NOVEMBER. HIGHS IN THE U30S AND LOWS IN THE MID-20S. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... 06Z UPDATE... VFR FOR ENTIRE TAF PERIOD...EXCEPT FOR QUESTION OF EARLY MORNING VALLEY FOG DEVELOPMENT IN KELM...AND SOME MVFR VIS FOR KITH. GREAT RADIATIONAL COOLING SET UP AND SHARP INVERSION...SUPPORTIVE OF KELM VALLEY FOG...IS COMPETING WITH VERY ATMOSPHERE /AFTER YET ANOTHER DAYTIME OF NO PRECIP AND LOW HUMIDITY LEVELS/. RAP MODEL SOUNDING OVERALL SEEMS TILTED IN FAVOR OF THE DRY AIR MASS...WITH THE MORE DEGRADED CONDITIONS STAYING TO OUR NORTH AND WEST /AS IS ALREADY OCCURRING FOR MANY TERMINALS ON THE ONTARIO PENINSULA/...WHERE HIGHER DEWPOINTS WERE ABLE TO ADVECT IN EARLIER. I HAVE TO RESPECT THE STILL FAIR SET UP FOR KELM...AND INCLUDED TEMPO IFR 11Z-13Z...BUT OTHERWISE HELD THE LINE AT MVFR VIS EARLY THIS MORNING. LIGHT EASTERLY FLOW WILL ALSO YIELD SOME MVFR VIS FOR A TIME EARLY THIS MORNING. FOR KRME...WILL HAVE TO WATCH FOR POSSIBLE MVFR LIGHT FOG BUT NOT IN TAF BECAUSE MOST LIKELY SCENARIO IS VFR. EXTENDED OUTLOOK... FRI...MVFR POSSIBLE ALONG AND BEHIND SHOWERY COLD FRONT AFTN/EVE. FRI NGT...MVFR CIGS. LATE IFR VIS POSS KSYR-KRME FROM LAKE -SHSN. SAT...MVRF/BRIEF IFR FROM LAKE -SHSN...MAINLY CNY TERMINALS. SUN...RESTRICTIONS PSBL IN SCT SHRA/SHSN. MON...MAINLY VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...CMG NEAR TERM...CMG/RRM SHORT TERM...CMG LONG TERM...PVN AVIATION...MDP
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1241 AM EST THU NOV 22 2012 .SYNOPSIS... HIGH PRESSURE WILL KEEP WARM AND DRY CONDITIONS ACROSS THE REGION THROUGH THANKSGIVING. A COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY MORNING. TEMPERATURES WILL FALL FRIDAY AFTERNOON AND BE WELL BELOW NORMAL OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... FOR THE EVENING UPDATE ADDED PATCHY TO AREAS OF FOG MAINLY FOR THE NORTHWESTERN PORTIONS OF THE FORECAST AREA AFTER MIDNIGHT TONIGHT. TEMP/DEWPOINT SPREADS ARE NARROWING RAPIDLY THIS EVENING ACROSS THESE AREAS WITH FOG ALREADY DEVELOPING JUST TO OUR NORTHWEST. THIS TREND HAS BEEN INDICATED WELL BY THE RAP SURFACE RH FIELDS THIS AFTERNOON AND THEREFORE IS BEING FOLLOWED FOR THE FOG FORECAST FOR TONIGHT. OTHERWISE MADE NO ADJUSTMENTS TO THE PREVIOUS FORECAST EXCEPT ADDING A FEW CIRRUS TO THE SKY GRIDS. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... SOUTHERLY WINDS WILL OCCUR BETWEEN RETREATING HIGH PRESSURE AND AN ADVANCING COLD FRONT THURSDAY AND THURSDAY EVENING. THIS WILL LEAD TO WELL ABOVE NORMAL TEMPERATURES ONCE AGAIN. HIGH CLOUDS WILL START STREAMING INTO THE REGION DURING THIS PERIOD. THE COLD FRONT WILL MOVE INTO WESTERN SECTIONS VERY LATE THURSDAY NIGHT AND CROSS THE REST OF THE FORECAST AREA FRIDAY MORNING. THERE WILL BE SHOWERS WITH THE COLD FRONT. BUT THERE IS SOME UNCERTAINTY ABOUT COVERAGE OF MEASURABLE RAIN. SO HAVE GONE HIGH CHANCE AND LOW LIKELY FOR THE REGION LATE THURSDAY NIGHT AND FRIDAY MORNING. SHOWERS WILL CLEAR OUT BY MIDDAY FRIDAY WITH CLOUDS DECREASING. TEMPERATURES SHOULD STAY RATHER WARM UNTIL FRONTAL PASSAGE EXCEPT FOR FAR EASTERN/SOUTHEASTERN COUNTIES WHERE READINGS MAY DROP OFF EARLY THURSDAY NIGHT. LOOKS LIKE A SITUATION WHERE THERE COULD BE 13Z LOWS AND 12Z HIGHS IN MANY LOCATIONS WITH READINGS FALLING THROUGH THE REST OF FRIDAY. WINDS WILL BE GUSTY BEHIND THE COLD FRONT WITH WIND CHILL VALUES DROPPING INTO THE UPPER 20S TO MID 30S BY LATE IN THE DAY. WINDS WILL DIMINISH SOMEWHAT FRIDAY NIGHT. ADDITIONAL CLOUD COVER MAY SPREAD INTO THE REGION WITH COLD AIR ADVECTION AND CYCLONIC FLOW OVER THE GREAT LAKES. FELT THAT GFS MOS LOWS LOOKED MORE REASONABLE IN THIS SCENARIO. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... COLD AIR MASS WILL BE IN PLACE ACROSS THE AREA ON SATURDAY WITH HIGH TEMPERATURES ONLY IN THE MIDDLE 30S. WITH WINDS OFF OF LAKE MICHIGAN ON SATURDAY SOME LIGHT LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE ACROSS NORTHERN PORTIONS OF THE FA. H8 WINDS WILL BECOME MORE WESTERLY SATURDAY EVENING AND PRECIPITATION CHANCES WILL COME TO AN END ACROSS THE FA. CLOUD COVER WILL DECREASE ACROSS THE AREA SATURDAY NIGHT ALLOWING TEMPERATURES TO DROP DOWN INTO THE LOW 20S ACROSS MOST LOCATIONS. WARMER AIR WILL GRADUALLY START TO WORK INTO THE AREA LATE DURING THE OVERNIGHT SATURDAY NIGHT AND THIS SHOULD HELP TO KEEP TEMPERATURES FROM FALLING INTO THE TEENS. TEMPERATURES CLIMB INTO THE 40S ON SUNDAY ACROSS THE AREA WITH SW FLOW HOWEVER THESE VALUES ARE STILL BELOW NORMAL FOR THIS TIME OF YEAR. THE MODELS START TO DIVERGE WITH THE STORM SYSTEM BEGINNING TO IMPACT THE AREA ON MONDAY. MODELS HAVE SHOWN QUITE A BIT OF RUN TO RUN INCONSISTENCY WITH THIS FEATURE. THE LATEST 12Z ECMWF HAS SHIFTED THE LOW QUITE A BIT FURTHER SOUTH FROM THE PREVIOUS MODEL SOLUTIONS AND HAVE DECIDED NOT TO JUMP ON THIS LATEST RUN JUST YET. INSTEAD...WENT WITH A 12Z GFS 00Z ECMWF BLEND. PRECIPITATION WILL BEGIN TO MOVE INTO THE AREA ON MONDAY WITH A GREATER COVERAGE IN PRECIPITATION EXPECTED MONDAY EVENING INTO TUESDAY. PRECIPITATION WILL GENERALLY BE IN THE FORM OF RAIN THROUGH THE DAYTIME HOURS ON TUESDAY EXCEPT FOR A LITTLE SNOW THAT MAY MIX IN AT TIMES ACROSS THE NORTH MONDAY INTO MONDAY NIGHT. WITH THE 12Z GFS 00Z ECMWF BLEND HAVE THE AREA OF LOW PRESSURE MOVING ALONG AND JUST NORTH OF THE INTERSTATE 71 CORRIDOR ON TUESDAY. COLDER AIR WILL QUICKLY WORK INTO THE AREA TUESDAY NIGHT AND ANY RESIDUAL PRECIPITATION WILL BEGIN TO CHANGE OVER TO SNOW ACROSS THE REGION. DRY CONDITIONS WILL RETURN TO THE AREA BY WEDNESDAY MORNING. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE CENTERED OVER THE REGION ATTM WILL SLIP EAST TODAY. LIGHT WINDS AND CLEAR SKIES WILL ALLOW SOME FOG FORMATION. KEPT FOG AT THE FOGGIER LOCATIONS...LUK AND ILN. ALLOWED LUK TO FALL TO IFR IN FOG...BUT KEPT ILN MVFR ATTM. H5 RIDGE ALSO OVER THE REGION WILL BREAK DOWN TODAY IN RESPONSE TO A S/W KICKING OUT OF THE PLAINS. HIGH LEVEL MOISTURE WILL BEGIN TO INCREASE DURING THE AFTN HOURS. AC DECK IS EXPECTED T0 WORK IN AFT 00Z. CDFNT SWINGING UP THE OH VALLEY WILL PUSH 4-5KFT CIGS INTO CVG AFT 06Z...WITH SCT SHRA AFT 10Z. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE FRIDAY. MVFR CEILINGS POSSIBLE SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS... NEAR TERM...LATTO SHORT TERM... LONG TERM...NOVAK AVIATION...SITES
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1045 PM CST WED NOV 21 2012 .DISCUSSION... STILL A LITTLE MIXY WITH SOUTHWESTERLY LOW LEVEL JET OVER EASTERN PART OF THE AREA. THIS HOLDING TEMPERATURES UP THIS EVENING...WITH READINGS STILL IN THE MID 50S TO LOWER 60S AS OF 03Z. MODELS DO NOT HAVE A GREAT GRASP ON THIS...WITH RAP THE CLOSEST THOUGH STILL A FEW DEGREES SHY AT 03Z. TREND IN THIS MODEL SEEMS REASONABLE THOUGH... WITH SLOW FALL AHEAD OF PRE-FRONTAL TROUGH...WHICH WILL TURN WINDS MORE WESTERLY AND SOMEWHAT LIGHTER OVERNIGHT. SHOULD SEE GREATER FALL AFTER THIS TROUGH PASSAGE...AND WITH COLD ADVECTION BEGINNING TO PUSH INTO WESTERN PARTS OF THE CWA PRIOR TO DAYBREAK...WILL LET GOING LOWS RIDE WITH MINIMAL CHANGES. UPDATED GRIDS/PFM HAVE BEEN SENT. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ MAINLY VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. SOUTHERLY WINDS OVERNIGHT WILL TRANSITION TO NORTHWESTERLY AND INCREASE EARLY ON THURSDAY...WITH GUSTS OF 30 TO 40 KTS LIKELY BY LATE MORNING AND AFTERNOON. REMOVED LLWS AT KSUX AS GUSTY SURFACE WINDS ARE CURRENTLY LIMITING SHEAR...HOWEVER IF SURFACE WINDS ARE ABLE TO DROP OFF OVER THE NEXT COUPLE HOURS LLWS MIGHT NEED TO BE REINTRODUCED...AS STILL SEEING CLOSE TO A 45 KT JET NEAR 1K FEET. SHOULD SEE SOME STRATUS FORM BEHIND THE FRONT TOMORROW AS WELL. CURRENTLY THINKING ANY MVFR CIGS STAY NORTH OF OUR CWA...ALTHOUGH WILL HAVE TO WATCH KHON AND TO A LESSER EXTENT KFSD...AS THEY COULD SEE A BRIEF PERIOD OF MVFR CIGS RIGHT BEHIND THE FRONT LATE TOMORROW MORNING INTO THE EARLY AFTERNOON HOURS...BEFORE DRYING AND CLEARING TAKES PLACE. WINDS WILL REMAIN GUSTY THROUGH THE EVENING HOURS...BUT SHOULD DROP A TAD. BUT AS A SECONDARY PUSH OF COLD AIR MOVES THROUGH...WE SHOULD SEE WINDS KICK UP A NOTCH WITH GUSTS BACK AROUND 35 KTS LATER IN THE EVENING INTO THE OVERNIGHT. /CHENARD && .PREV DISCUSSION.../ISSUED AT 241 PM CST/ BRISK SOUTH SOUTHWESTERLY FLOW WILL CONTINUE ACROSS MUCH OF THE AREA TONIGHT WITH THE APPROACH OF A SURFACE TROUGH FROM THE WEST. THIS WILL ALLOW FOR WINDS TO STAY UP OVERNIGHT...MORE SO IN THE EAST...AND IT WILL BE A MILD NIGHT WITH LOWS PRIMARILY IN THE 40S. THE SURFACE TROUGH/FRONTAL BOUNDARY WILL SWING THROUGH THE AREA ON THURSDAY...AND WITH STRONG COLD AIR ADVECTION/STEEP LOW LEVEL LAPSE RATES/WINDS GENERALLY 40 TO 45 KTS AT THE TOP OF THE MIXED LAYER/AND A TIGHTENING GRADIENT IT WILL BE A WINDY DAY...AND EXPANDED THE WIND ADVISORY OVER THE ENTIRE CWA. WHILE THE ADVISORY WILL BE MARGINAL IN SOME AREAS...AND STRONGEST WINDS MAY ONLY PERSIST FOR 2 OR 3 HOURS WITH THE FRONTAL PASSAGE...FOR THE SAKE OF SIMPLICITY AND COORDINATION WITH SURROUNDING OFFICES ELECTED TO INCLUDE THE ENTIRE AREA AS CRITERIA IS EXPECTED TO BE CLOSE ENOUGH. WHILE THE COLDEST AIR WILL NOT COME IN UNTIL THURSDAY NIGHT...WITH 925 MB TEMPERATURES PROGGED TO BE A GOOD 10 TO 15 DEGREES C COOLER ON THURSDAY AFTERNOON OVER TODAY...WILL HAVE HIGHS RANGING FROM THE UPPER 40S TO MID 50S ACROSS THE AREA...THOUGH IT WILL OBVIOUSLY FEEL COLDER WHEN THE WINDS ARE FACTORED IN. A STRONG SURGE OF COLD AIR WILL MOVE SOUTH ON THURSDAY NIGHT ALONG WITH GUSTY NORTHWEST WINDS. MODELS IN PRETTY GOOD AGREEMENT WITH THE AMOUNT OF COOLING...JUST SOME MINOR DIFFERENCES ON THE TIMING OF THE FRONT. THE NAM SEEMS TO HANDLE THESE LOW LEVEL FRONTAL FEATURES BEST THIS TIME OF YEAR SO USED THAT TO ACCOUNT FOR THE SOMEWHAT NON DIURNAL NATURE OF TEMPERATURES AS THEY DROP THROUGH THE EARLY MORNING OF FRIDAY BEFORE SLOWLY RISING THROUGH THE DAY. LOWS WILL BE MODERATED A BIT BY THE STRONG FLOW SO WENT CLOSEST TO THE CONSRAW OUTPUT WHICH HANDLES WINDY NIGHTS THE BEST...SO MAINLY LOWER TO MID 20S FOR LOWS. HIGH TEMPERATURES FRIDAY WILL NOT REBOUND MUCH AS COLD ADVECTION CONTINUES AND CLOUDS IN THE EAST ARE SLOW TO ERODE. MAINLY AIMING FOR 250 TO 30 IN THE EAST AND 30 TO 35 IN THE WEST. FRIDAY NIGHT INTO SATURDAY WILL SEE A FAST MOVING SURFACE HIGH PRESSURE MOVE THROUGH WITH BREEZY SOUTHERLY FLOW DEVELOPING ON SATURDAY. TWEAKED LOWS DOWN JUST A TOUCH IN THE EASTERN CWA AND LEFT THEM ABOUT AS IS IN THE WESTERN CWA. WITH THE RETURN FLOW SETTING UP IN THE FAR SOUTH AND WEST CWA ALSO HAVE GRADUALLY WARMING TEMPERATURES IN THOSE AREAS THROUGH SUNRISE. BY SATURDAY THIS STRONG SOUTHERLY FLOW WILL BE IN PLACE WITH A FAIRLY STRONG THERMAL GRADIENT DEVELOPING ACROSS THE CWA. EXPECTING TEMPERATURES TO STRUGGLE A BIT IN THE EAST WHERE SOUTHERLY WINDS WILL BE SLOW TO SET UP...SO ONLY MID 30S. IN THE SOUTHWEST CWA A SURGE OF WARMER AIR SHOULD ALLOW TEMPERATURES TO BUMP UP INTO THE LOWER 50S. IN THE LATTER PERIODS(SUN/WED)...A TROUGH OF LOW PRESSURE WILL DIG INTO THE CENTRAL ROCKIES SUNDAY AFTERNOON THEN SPREAD ACROSS THE CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. WHILE THERE WILL BE A SMALL CHANCE FOR LIGHT SNOW DURING THIS TIME...WITH SO MUCH NORTHWEST JET ENERGY UPSTREAM FEEL THAT THE WAVE MAY DIG A LITTLE FARTHER SOUTH THAN MODELS CURRENTLY PROJECT SO DO NOT PLAN ON INCREASING PROBABILITIES FOR MEASURABLE SNOWFALL. IF THE WAVE DOES DIVE A LITTLE FARTHER SOUTHWEST ON SUNDAY THE AMOUNT OF WARM AIR THAT MAKES IT THIS FAR NORTH WILL BE MINIMAL WITH A NORTH TO NORTHEAST WIND DEVELOPING THROUGH THE DAY. WILL CONTINUE TO KEEP HIGHS FAIRLY COOL BUT SEASONAL FROM THE UPPER 30S NORTH TO THE MID 40S SOUTH. AS THE WAVE PASSES ON SUNDAY NIGHT COLDER AIR WILL POUR INTO THE REGION SETTING UP A FAIRLY COLD MONDAY THROUGH THURSDAY TIME PERIOD. WILL CONTINUE TO LEAN TOWARDS THE MORE CONSISTENT ECMWF WHICH BUILDS THE HIGH PRESSURE SOUTH AND IS MORE STUBBORN ABOUT ALLOWING WARM AIR TO SURGE NORTHEAST AS A WEAK WAVE PASSES ON TUESDAY NIGHT INTO WEDNESDAY. /08 && .FIRE WEATHER.../ISSUED AT 333 PM CST/ THANKSGIVING DAY WILL SEE VERY STRONG NORTHWEST WINDS DEVELOP DURING THE DAY AND WITH VERY DRY CONDITIONS A VERY HIGH FIRE DANGER WILL BE IN PLACE. THE STRONGEST WINDS WILL BE IN CENTRAL SOUTH DAKOTA DOWN THE MISSOURI RIVER VALLEY THROUGH EARLY AFTERNOON...THEN TRANSITION INTO EASTERN SOUTH DAKOTA...SOUTHWEST MINNESOTA AND NORTHWEST IOWA FROM EARLY AFTERNOON INTO THE EVENING. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR IAZ001>003- 012>014-020>022-031-032. MN...WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR MNZ071-072-080- 081-089-090-097-098. NE...WIND ADVISORY FROM 9 AM TO 6 PM CST THURSDAY FOR NEZ013. WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR NEZ014. SD...WIND ADVISORY FROM 9 AM TO 6 PM CST THURSDAY FOR SDZ038-050-052- 053-057>060-063>066-068>070. WIND ADVISORY FROM NOON TO 6 PM CST THURSDAY FOR SDZ039-040- 054>056-061-062-067-071. && $$
AREA FORECAST DISCUSSION
NWS AMARILLO TX
1119 PM CST WED NOV 21 2012 .AVIATION... 06Z TAF CYCLE UPPER TROUGH TO PUSH THROUGH THE PANHANDLES BETWEEN 12Z AND 18Z THURSDAY WITH NORTHWESTERLY UPPER FLOW BEHIND THE DEPARTING UPPER TROUGH LATE THURSDAY AND THURSDAY NIGHT. VFR CONDITIONS WITH CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS TONIGHT...AND CLEAR TO SCATTERED HIGH LEVEL CLOUDS BY THURSDAY AFTERNOON AND THURSDAY NIGHT. LOW LEVEL SOUTHERLY JET OVER THE PANHANDLES TONIGHT WILL ALLOW FOR GUSTY SOUTHERLY WINDS 15 TO 25 KNOTS WITH OCCASIONAL HIGHER GUSTS...THEN COLD FRONT MOVES THROUGH THE GUYMON AND DALHART TAF SITES AROUND 13Z TO 15Z THURSDAY SHIFTING THE WINDS TO NORTHERLY 15 TO 25 KNOTS WITH HIGHER GUSTS. COLD FRONT MOVES THROUGH THE AMARILLO TAF SITE BETWEEN AROUND 16Z AND 18Z THURSDAY WITH WINDS BECOMING NORTHERLY 15 TO 25 KNOTS WITH HIGHER GUSTS. NORTHERLY WINDS GRADUALLY DIMINISH BETWEEN 21Z THURSDAY AND 02Z FRIDAY TO AROUND 10 TO 20 KNOTS UNTIL 06Z FRIDAY. SCHNEIDER && .PREV DISCUSSION... /ISSUED 959 PM CST WED NOV 21 2012/ UPDATE... QUICK UPDATE TO TWEAK OVERNIGHT WINDS...TEMPS...AND DEWPOINTS UPWARD BASED ON CURRENT TRENDS. KB PREV DISCUSSION... /ISSUED 518 PM CST WED NOV 21 2012/ AVIATION... 00Z TAF CYCLE UPPER TROUGH WILL MOVE ACROSS THE TEXAS AND OKLAHOMA PANHANDLES TONIGHT PRODUCING CONSIDERABLE MID AND HIGH LEVEL CLOUDINESS AND USHERING IN A COLD FRONT THANKSGIVING DAY MORNING. VFR CONDITIONS ARE EXPECTED ALONG WITH SOUTHERLY WINDS 15 TO 20 KNOTS WITH SOME HIGHER GUSTS POSSIBLE TONIGHT...THEN WINDS SHIFTING TO THE NORTHWEST AND NORTH 15 TO 25 KNOTS WITH HIGHER GUSTS AFTER 14Z TO 17Z THANKSGIVING DAY. WIND SPEEDS ARE EXPECTED TO GRADUALLY DIMINISH AFTER 20Z TO 22Z THANKSGIVING DAY TO AROUND 15 KNOTS. SCHNEIDER PREV DISCUSSION... /ISSUED 415 PM CST WED NOV 21 2012/ DISCUSSION... CONTINUED DRY CONDITIONS AND PERIODIC FRONTAL PASSAGES HIGHLIGHT THE FORECAST PERIOD. SOUTHWESTERLY WINDS AND CLOUD COVER HAVE INCREASED TODAY IN ADVANCE OF A SHORTWAVE TROUGH NOW EJECTING THROUGH THE AMBIENT SOUTHWESTERLY FLOW ALOFT. WHILE MOST OF THE FORCING/ASCENT AND MEANINGFUL RAIN CHANCES ASSOCIATED WITH THIS FEATURE WILL REMAIN WELL SOUTH OF THE AREA...SOME ENHANCED VORTICITY/DEEPENING OF THE TROUGH HAS EMERGED THIS AFTERNOON OVER CENTRAL NEW MEXICO. ISOLATED HIGH-BASED CONVECTION HAS DEVELOPED NEAR ROSWELL. ALL NWP SOLUTIONS MINIMIZE PROSPECTS FOR PRECIPITATION IN THE PANHANDLES AS THIS TRANSLATES OVER THE REGION TONIGHT. ONLY THE RAP DEPICTS THE SMALLEST HINT OF QPF OVER THE SOUTHWESTERN PANHANDLE. THUS WE HAVE MAINTAINED A DRY FORECAST WITH GRIDDED POPS AT/BELOW 10 PERCENT. A FRONT IS EXPECTED TO PUSH ACROSS THE PANHANDLES AFTER 12-15Z THURSDAY IN WAKE OF THE PASSING SHORTWAVE TROUGH AXIS. 3-HR PRESSURE RISES AROUND 4 MB OVER KANSAS WILL SUPPORT POST FRONTAL WINDS OF 15 TO 25 MPH...ESPECIALLY OVER THE OKLAHOMA PANHANDLE AND THE NORTHERN TEXAS PANHANDLE. ALL INDICATIONS OF SUFFICIENT LIFT/MOISTURE TO SUPPORT CONVECTION ALONG THE FRONT ARE DISPLACED WELL EAST AND SOUTH OF THE REGION. A 1035-1037 MB CONTINENTAL SURFACE HIGH WILL PUSH SOUTHWARD THROUGH THE PLAINS IN WAKE OF THE FRONT. THIS WILL RESULT IN NOTABLY COOLER TEMPERATURES /SOME 5 DEGREES BELOW SEASONAL AVERAGES/ BY FRIDAY. THE COOL SURFACE RIDGE WILL TRANSLATE SOUTHEAST TOWARD THE LOWER MISSISSIPPI VALLEY...LENDING TOWARD TEMPERATURE MODERATION OVER THE PANHANDLES THROUGH THE WEEKEND. THIS AS LOW AMPLITUDE RIDGING OVER THE WEST RESULTS IN MODEST NORTHWESTERLY FLOW OVER THE CENTRAL/SOUTHERN PLAINS AND LEE TROUGHING. ATTENTION THEN SHIFTS TOWARD A SHORTWAVE TROUGH AND ASSOCIATED FRONTAL PASSAGE EARLY NEXT WEEK. THE INITIAL FRONTAL PASSAGE WILL OCCUR DURING THE LATE SUNDAY/EARLY MONDAY TIMEFRAME...AND MAY RESULT IN PROBLEMATIC TEMPERATURE FORECASTS INITIALLY. THE FRONT WILL FINALLY PUSH SOLIDLY THROUGH BY LATE MONDAY AS THE APPROACHING SHORTWAVE TROUGH AMPLIFIES IN NORTHWESTERLY FLOW. SOME SOLUTIONS GENERATE LIGHT QPF IN PROXIMITY TO THE NORTHERN AND EASTERN PANHANDLES...BUT CONFIDENCE IN SUFFICIENT FORCING/MOISTURE IS NOT HIGH AND THE CURRENT DRY FORECAST CONTINUES TO APPEAR VALID. FIRE WEATHER... ONGOING ELEVATED FIRE WEATHER OVER THE WESTERN AND CENTRAL OKLAHOMA PANHANDLE AND NORTHWESTERN TEXAS PANHANDLE WILL DIMINISH BY EARLY EVENING. CONCERNS FOR ELEVATED CONDITIONS WILL AGAIN EXIST THURSDAY... AS POST FRONTAL WINDS INCREASE INTO THE 15 TO 20 MPH RANGE AND AFTERNOON HUMIDITY MINIMA DROP TOWARDS 15 PERCENT AGAIN OVER THE WESTERN OKLAHOMA PANHANDLE AND THE NORTHWESTERN TEXAS PANHANDLE. OTHERWISE...ELEVATED OR CRITICAL CONDITIONS ARE NOT ANTICIPATED THROUGH THE REMAINDER OF THE PERIOD. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 11/08
AREA FORECAST DISCUSSION
NWS LINCOLN IL
226 AM CST SAT NOV 24 2012 .DISCUSSION... ISSUED 225 AM CST SAT NOV 24 2012 LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS. THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A STORM SYSTEM PASSES TO OUR SOUTH. SHORT TERM...TODAY THROUGH MONDAY NIGHT... LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD. RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET. TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY SHOULD BE ABOUT 10-15 DEGREES WARMER. LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST. FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA. LONG TERM...TUESDAY THROUGH FRIDAY... MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY. GEELHART && .AVIATION... ISSUED 1149 PM CST FRI NOV 23 2012 MVFR CEILINGS CURRENTLY OVER NORTHERN ILLINOIS HAVE BEEN CREEPING SLOWLY SOUTHWARD THIS EVENING AND ARE NOW NEARING THE I-74 TERMINALS. CLOUDS ARE BEING PUSHED SOUTHWARD AS A RESULT OF N/NW FLOW ON THE BACK SIDE OF A DEPARTING UPPER LOW OVER QUEBEC. GIVEN N/NW FLOW NOTED ON AREA VAD WIND PROFILERS AND CURRENT SATELLITE TRENDS...HAVE ADDED A PERIOD OF LOW VFR CEILINGS OF 3500FT AT BOTH KBMI AND KCMI BETWEEN 06Z AND 11Z. CLOUDS WILL DROP S/SE...THEN GRADUALLY SHIFT EASTWARD EARLY SATURDAY MORNING AS UPPER LOW PULLS FURTHER AWAY. SKIES WILL THEN BE MOSTLY CLEAR ACROSS THE BOARD...UNTIL MID/HIGH CLOUDS INCREASE FROM THE WEST DURING THE AFTERNOON/EVENING. MODELS HAVE BEEN SUGGESTING A PERIOD OF WARM ADVECTION TYPE CLOUDS AOA 9000FT SPREADING INTO KPIA AND KSPI BY AROUND 18Z...THEN FURTHER EAST TO KCMI BY 21Z. WINDS WILL INITIALLY BE FROM THE NORTHWEST AT 5 TO 10KT TONIGHT INTO SATURDAY MORNING...THEN WILL BACK TO THE SOUTH BY EVENING. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
341 AM EST SAT NOV 24 2012 .SHORT TERM... FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT WILL BACK POPS OFF CONSIDERABLY. OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR TYPICAL LOCAL COLD SPOTS. UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED GREATER MIXING AND GAVE A +1 BUMP HIGHER. && .LONG TERM...MONDAY THROUGH FRIDAY MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM. ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE) SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH SHEARED WAVE(S). && .AVIATION... MVFR CONDS THIS MORNING WILL GRADUALLY IMPROVE INTO THIS AFTN W/CONTD LL DRY ENTRAINMENT. SIG SHSN AT KSBN LOOKING MORE AND MORE DOUBTFUL AND WILL MOST LIKELY BE DROPPED W/12Z ISSUANCE AS DRY AIR CLEARLY WINNING OUT SO FAR. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...T
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
902 PM CST FRI NOV 23 2012 .DISCUSSION... COORD WITH WFO BIS AND ADDED A LOW POP FOR -SN IN DVL BASIN AFTER MIDNIGHT. WARMA ADVECTION AND MID CLOUDS IN WRN ND CAUSING SOME BRIEF -SN PER RADAR AND THIS SHOULD MOVE INTO DVL BASIN AFTER MIDNIGHT. SOME OF THIS VERY LIGHT WARM ADV SNOW WILL MOVE INTO NORTHEAST ND AFTER 12Z PER FCST. 00Z NAM IS MORE BULLISH WITH LIGHT SNOW CHANCES IN THE AFTN FOR NRN VALLEY INTO NW MN AHD OF NEXT COLD FRONT. FOR THE IMMEDIATE FUTURE...TEMPS AND CLOUD COVER PLAYING A BIT OF HAVOC. LOWER STRATOCU REMAINS IN A MAND FROM PORTAGE MB THROUGH THE RED RIVER VALLEY INTO NW/WCNTRL MN. CLEARING WEST OF LANGDON TO MAYVILLE TO WAHPETON LINE HASNT MOVED AND THAT CLEAR AREA IS NOW SEEING HIGH CLOUDS MOVE IN AND SOME ALTOCU WILL MOVE IN TOWARD 06Z IN WARM ADV ZONE. TEMPS BOTTOMING OUT NOW AROUND -4 OR SO ROLLA AREA TO 3-5 DEGREES DOWN THROUGH DEVILS LAKE TO COOPERSTOWN TO WEST OF FARGO. THIS AREA WILL SEE TEMPS SLOWLY RISE OVERNIGHT AS CLOUDS MOVE IN. IN THE RED RIVER VALLEY LATEST RAP MODEL KEEPS CLOUDS IN AND RIGHT NOW DONT HAVE MUCH HOPE FOR CLEARING MUCH OF THE STRATOCU MVFR DECK FOR A WHILE. CLEAR WEDGE IN THE ROSEAU AREA MAY MAINTAIN ITSELF TONIGHT AND MIGHT EXPAND SOUTH A BIT AND WILL GO A BIT LOWER TEMPS THAT AREA WITH NR ZERO IN SOUTHEAST MANITOBA. && .PREV DISCUSSION... /ISSUED 628 PM CST FRI NOV 23 2012/ DISCUSSION... SENDING AN AN EARLY UPDATE AS TEMPS ARE FALLING QUTIE FAST IN CLEAR WEDGE IN WRN FCST AREA.... -4 TO -6 ALREADY IN THE ROLLA AREA AND ADJACENT MANITOBA WITH 5 DEGREES DOWN INTO VALLEY CITY- COOPERSTOWN REGIONS. ALSO DID UP SKY COVER AND HANG ON TO STRATOCU AND FLURRIES TIL AT LEAST 03Z IN THE RED RIVER VALLEY. SOME SLOW CLEARING IS ADVANCING EAST...BUT HARD TO TELL VIA SATELLITE WITH THESE TEMPS. PREV DISCUSSION... /ISSUED 254 PM CST FRI NOV 23 2012/ SHORT TERM... SNOW CHANCES SATURDAY AND TEMPERATURES THROUGHOUT THE PERIOD WILL BE THE PRIMARY FORECAST PROBLEMS FOR THE SHORT TERM. HIGH PRESSURE CONTINUES TO SLOWLY MOVE INTO THE CWA THIS AFTERNOON AND WILL BE CENTERED OVER THE RED RIVER VALLEY THIS EVENING. CLOUDS AND FLURRIES HAVE CONTINUED INTO THE AFTERNOON. THINK THAT FLURRIES SHOULD END AND CLOUDS BEGIN TO DECREASE AT LEAST OVER THE WESTERN AND CENTRAL AS WE LOSE DAYTIME HEATING. THERE SHOULD BE A SHORT PERIOD WITH PARTLY CLOUDY SKIES AND LIGHT WINDS PARTICULARLY OVER THE NORTHWESTERN CWA THIS EVENING. TEMPS IN THAT AREAS SHOULD DROP LIKE A ROCK DURING THE EVENING...PARTICULARLY AS TEMPS HAVE STAYED IN THE SINGLE DIGITS THIS AFTERNOON. HOWEVER...A SFC TROUGH SHOULD STRENGTHEN ALONG THE MT/ND BORDER AND BRING INCREASING CLOUDS AND SOUTHERLY WINDS. THINK THAT AT LEAST THE WESTERN COUNTIES SHOULD SEE INCREASING TEMPS AFTER MIDNIGHT TONIGHT. WENT NON-DIURNAL FOR HOURLIES OVERNIGHT. TOMORROW...A DECENT SHORTWAVE TROUGH WILL MOVE THROUGH MANITOBA INTO ONTARIO. THE SFC TROUGH AXIS MOVES INTO THE RED RIVER VALLEY DURING THE DAY. THERE SHOULD BE SOME DECENT WARM AIR ADVECTION AND ISENTROPIC LIFT ALONG WITH THE SFC TROUGH AXIS. MOST OF THE MODELS HAVE THE BEST QPF WITH THE MAIN UPPER LOW TO OUR NORTH...BUT MORE RUNS ARE BRINGING SOME LIGHT PRECIP INTO OUR NORTHERN COUNTIES...PARTICULARLY ON THE MINNESOTA SIDE. BUMPED UP POPS A BIT FOR SATURDAY AFTERNOON...PUTTING SOME SNOW ACCUMULATIONS OF UP TO AN INCH IN THE NORTHEASTERN COUNTIES. WITH WARM AIR ADVECTION FOR MUCH OF THE DAY TEMPS SHOULD RETURN BRIEFLY TO THE UPPER 20S TO LOW 30S EVEN WITH SOME CLOUD COVER. THE UPPER TROUGH WILL DIG INTO ONTARIO AND MOVE OFF TO THE EAST BY SUNDAY...WHICH WILL HELP BRING ANOTHER STRONG COLD FRONT INTO THE AREA. TIMING OF THE FRONT IS A BIT UNCERTAIN. THE GFS BRINGS IT DOWN INTO THE CWA THE FASTEST...WHILE THE NAM IS STILL IN THE FAR NORTHERN CWA AT 12Z AND THE ECMWF IS IN BETWEEN. THE GFS SEEMS TO BE AN OUTLIER SO AT THIS POINT THINK THE STRONG COLD AIR SURGE WITH 850MB TEMPS IN THE TEENS BELOW ZERO WILL COME THROUGH DURING THE DAY ON SUNDAY. WENT WITH FALLING TEMPS DURING SUNDAY AFTERNOON WITH STRONG COLD AIR ADVECTION. ONLY A FEW FLURRIES ARE EXPECTED WITH THE SYSTEM...BUT WILL HAVE TO WATCH IN CASE WIND GUSTS ALONG THE FRONT BLOW SOME SNOW AROUND. SUNDAY NIGHT SHOULD BE VERY COLD WITH TEMPS IN THE SINGLE DIGITS UNDER SFC HIGH PRESSURE. MONDAY SHOULD BE FAIRLY QUIET AS A SHORTWAVE TROUGH MISSES US JUST TO THE SOUTHWEST OF THE CWA. WITH A COLD START AND NOT MUCH MIXING EARLY IN THE DAY...HIGHS SHOULD REMAIN FAIRLY COLD IN THE TEENS TO LOW 20S...ALTHOUGH THE FAR WESTERN COUNTIES SHOULD START TO SEE SOME WARM AIR ADVECTION LATE IN THE DAY. LONG TERM...MONDAY NIGHT THROUGH FRIDAY MODELS ARE IN OVERALL DECENT AGREEMENT WITH MASS FIELDS, THOUGH DISTINCT TIMING DIFFERENCES DO EXIST. UPPER FLOW AT THE START OF THE FCST PD IS NW ACROSS THE UPPER MIDWEST...TURNING MORE ZONAL AFTER MIDWEEK AS RIDGING ALONG THE WEST COAST DAMPENS. AN UPPER S/WV IS EXPECTED TO DROP SEWD MON NIGHT BRINGING A LOW END CHC POPS TO THE FAR NORTHERN ZNS MON NIGHT INTO TUE. WITH THE UPPER FLOW TRANSITIONING TO A MORE ZONAL PATTERN....850 TEMPS MODERATE TO ABOVE ZERO BY MIDWEEK. EXPECT MAX TEMPS TO BE SLIGHTLY BELOW NORMAL THROUGH THU BEFORE CLIMBING ABOVE FREEZING ON FRI. WITH SFC HIGH PRESSURE AFTER TUE...KEPT THE FCST DRY THROUGH THE REST OF THE WEEK. AVIATION... MVFR CIGS THIS AFTN WILL GIVE WAY TO VFR CONDS BY 00Z ALL SITES EXCEPT FOR POSSIBLY KBJI. BRIEF PERIODS OF LIGHT SNOW SHOWERS HAVE OCCURRED FROM THE VALLEY EAST THIS AFTN...HOWEVER EXPECT THIS ACTIVITY TO DIMINISH DURING THE LATE AFTN. NW WINDS BETWEEN 10 AND 20 KTS WILL BECOME LIGHT AND VARIABLE AS HIGH PRESSURE CONT TO BUILD ITO THE AREA. WINDS WILL TURN MORE SOUTHERLY BETWEEN 06Z AND 12Z SAT. A SCTD MID DECK SHOULD MOVE INTO THE VALLEY BY 12Z SAT MORNING WHILE SLY WINDS INCREASE TO 10 TO 15 KTS BY THE END OF THE FCST PD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
829 PM CST FRI NOV 23 2012 .DISCUSSION...LATEST RADAR LOOP IS SHOWING A NICE BAND OF WARM ADVECTION CLOUDS AND POSSIBLY SOME LIGHT SNOW TRACKING FROM WESTERN INTO CENTRAL NORTH DAKOTA. GFS/NAM AND LATEST RAP ARE INDICATING SOME VERY LIGHT QPF ACROSS THE NORTH. NO GROUND TRUTH YET BUT LIGHTS IN WEATHER CAMERAS IN THE NORTHWEST LOOK A LITTLE FUZZY INDICATING THERE MAY BE SOME LIGHT SNOW REACHING THE GROUND AND CEILINGS HAVE LOWERED TO AROUND 5-7KFT IN THE NORTHWEST. WENT AHEAD AND ADDED A SLIGHT CHANCE OF LIGHT SNOW ACROSS THE NORTHWEST AND NORTH CENTRAL TONIGHT. SOME RETURNS EXTENDING INTO THE SOUTH CENTRAL BUT MORE DRY AIR HERE AND BETTER MID LEVEL FORCING REMAINS ACROSS THE NORTH. OTHERWISE NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH THE 00Z TAF PERIOD. INCREASING MID/UPPER LEVEL CLOUDS OVER NORTH DAKOTA AHEAD OF A WARM FRONT SET TO MOVE INTO THE REGION LATER TONIGHT. DID BRING A PERIOD OF LIGHT SNOW TO KMOT FROM 03-06 UTC WITH NO RESTRICTION TO VISIBILITY. WIND SHIFT FROM THE SOUTH TO THE WEST FOLLOWING A COLD FRONTAL PASSAGE LATE TOMORROW MORNING FOR ISN/DIK AND AFTERNOON FOR BIS/MOT/JMS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TWH/LTH
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1036 AM EST SAT NOV 24 2012 .SYNOPSIS... COOLER AND BLUSTERY CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. UNCERTAINTY REMAINS REGARDING THE TRACK AND INTENSITY OF A POTENTIAL STORM NEXT TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030 AM UPDATE... COLD FRONT WAS EXITING THE COASTAL WATERS. WEST TO NORTHWEST WINDS WERE GUSTING AS HIGH AS 30 KT AT BOS AND 28 KT AT CEF. AM EXPECTING WIND GUSTS TO REMAIN IN THE 20-25 KT RANGE THIS AFTERNOON WITH A FEW HIGHER GUSTS. SURFACE WINDS MAY INCREASE TOWARD EVENING IN WESTERN AREAS AS 850 MB WINDS STRENGTHEN. DRIER AIR HAS FILTERED IN WITH DEWPOINTS ALREADY IN THE UPPER TEENS AND LOWER 20S ACROSS THE REGION. AFTER INITIAL SUNSHINE...SOME CUMULUS CLOUDS HAD ALREADY FORMED IN SOUTHWEST NH AND WESTERN MA. THESE SHOULD SPREAD EAST ACROSS MUCH OF THE INTERIOR BUT MAY NOT REACH THE SOUTHERN COASTAL AREAS. NO CHANGES TO TEMPERATURES FROM PREVIOUS FORECAST...WITH HIGHS IN THE MID 40S AND HOLDING RELATIVELY STEADY OR SLOWLY FALLING INTO THE UPPER 30S. A PERSISTENT LAKE EFFECT SNOW SHOWER BAND WAS MOVING ACROSS NEW YORK AND IT WAS FLURRYING AT ALBANY AS OF 10 AM. THE RAP MODEL SHOWS FLURRIES MAKING IT INTO BERKSHIRE COUNTY AND SOUTHERN VT BUT NOT ANY FURTHER WITH THE DOWNSLOPE DRYING FLOW. WILL KEEP AN EYE ON THIS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... TONIGHT... THE CONTINUED STRONG COLD AIR ADVECTION THRU THE MAJORITY OF THE ATMOS COLUMN WILL KEEP LOW-LVLS WELL-MIXED TO H8. WIND GUSTS LIKELY TO CONTINUE AT 25 TO 30 MPH /GALES OVER THE WATERS/. H85 W/NW FLOW WILL BE SLIGHTLY STRONGER WITHIN THE TIGHTER PRES GRADIENT. LOOKING AT H85 TEMPS AROUND -10 TO -12C. WHILE LOOKING TO REMAIN MOSTLY CLEAR... WINDS WILL DIMINISH THE POTENTIAL FOR EFFECTIVE NOCTURNAL COOLING. STILL...ANTICIPATING LOWS DOWN INTO THE LOW 20S WITH UPR TEENS TO THE N/W INTERIOR NEW ENGLAND. SUNDAY... ANOTHER DAY OF CONTINUED BLUSTERY W/NW CONDITIONS WITH GUSTS 25 TO 30 MPH /POTENTIAL FOR CONTINUED GALES ACROSS THE WATERS/. VERY LITTLE CHANGE IN THE AIRMASS WITH H85 TEMPS AROUND -8 TO -10C...SO EXPECTING MAX TEMPS AROUND THE LOW 40S WITH PERHAPS INCREASING CLOUDS LATE WITH WEAK WAVE ENERGY TRANSLATING THRU THE LONGWAVE PATTERN /CLIPPER SYSTEM/. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... * COLDER...DRY WEATHER EXPECTED EARLY NEXT WEEK * A STORM IS LIKELY TO AFFECT THE AREA MID WEEK OVERVIEW AND MODEL PREFERENCES... 24/00Z MODEL GUIDANCE SUITE CONTINUES TO SHOW DECENT RUN-TO-RUN CONSISTENCY AND GOOD AGREEMENT BETWEEN EACH OTHER THROUGH THE MID TERM PERIOD. THEY HAVE ALSO BEGUN TO CONVERGE ON THE MID WEEK SYSTEM THAT HAS BEEN DISCUSSED OF LATE. THIS IS NOT TO SAY ITS A SLAM DUNK AT THIS POINT...BUT MODELS ARE NOW CLOSER TO ONE ANOTHER IN THE LOW TRACK THAN PREVIOUS RUNS. ESSENTIALLY...WITH THE ZONAL PROGRESSIVE FLOW ALOFT SUGGESTED IN ALL MODELS...THE GFS/ECMWF AND RESPECTIVE ENSEMBLE MEANS NOW SUPPORT CYCLOGENESIS OFFSHORE OF THE MID ATLANTIC STATES AND PUSHING THAT LOW FURTHER E THAN /ESPECIALLY THE GFS AND GEFS/ GUIDANCE WAS PREVIOUSLY. THEREFORE...THERE IS A BIT MORE SUPPORT FOR A COASTAL STORM RATHER THAN ONE THAT PUSHES INLAND. THIS ALSO FAVORS A COOLER SOLN AS WELL. THERE ARE STILL SIGNIFICANT TRACK DIFFERENCES THOUGH AS THE GFS AND GEFS MEAN BRINGS THE LOW IN CLOSE PROXIMITY TO THE 40/70 BENCHMARK WHILE ECMWF/ECENS ARE MUCH FURTHER OFFSHORE WITH LITTLE IMPACT ON SRN NEW ENGLAND. WILL BEGIN TO TREND GRIDS TOWARD THIS COASTAL/COOL SOLN BUT WITH AN EYE TOWARD UNCERTAINTY IN FINAL IMPACTS...WHICH WILL NEED TO BE MONITORED THROUGH THE WEEKEND AND EARLY NEXT WEEK. COOL HIGH PRES BOOKEND THIS STORM EARLY THIS COMING WEEK AND AGAIN LATE IN THE WEEK...AND GUIDANCE IS ACTUALLY IN GOOD AGREEMENT HERE SO CONFIDENCE IS HIGHER IN COOL/DRY CONDITIONS SURROUNDING THE STORM TEMPORALLY. DETAILS... SUN NIGHT INTO EARLY TUE... STRONG UPPER LVL ZONAL JET WITH COOL NW FLOW AT THE SFC SUPPORT TEMPS GENERALLY BELOW NORMAL AND OCCASIONALLY BLUSTERY CONDITIONS THROUGH THIS PERIOD. MON...A FAST MOVING SHORTWAVE MAY ENHANCE THE LOW LVL COLD ADVECTION AND USHER IN SOME LOW CLOUDS ASSOCIATED WITH STRATO-CU DEVELOPMENT DOWNSTREAM OF THE GREAT LAKES. AT THIS POINT...THE STRONG COLD ADVECTION SHOULD PREEMPT ANY PRECIP DEVELOPMENT WITH THIS WAVE...SO DRY CONDITIONS ARE LIKELY TO CONTINUE. TUE AFTERNOON INTO WED NIGHT... AS MENTIONED EARLIER CONFIDENCE IS /ALBEIT A LITTLE BIT/ HIGHER THAN PREVIOUS FORECASTS REGARDING THE TRACK OF A LOW PRES DURING THE MID WEEK TIMEFRAME. MOST GUIDANCE NOW SUPPORTS THE LOW TRACKS OFFSHORE...A SUGGESTION THE THE ECENS/OPERATIONAL ECMWF HAS SUPPORTED FOR SOME TIME NOW. THEREFORE...A COLDER SOLN IS POSSIBLE...BUT GIVEN THE TRACK COULD BE CLOSE TO THE BENCHMARK /THE GFS/CMC TRACK/ OR WELL OFFSHORE /THE ECMWF TRACK/ THE ACTUAL EFFECTS ON SRN NEW ENGLAND REMAIN A BIT OF A QUESTION MARK. AT THIS POINT THE MID LVL FLOW REGIMES ON BOTH OPERATIONAL MODELS DO SO SOME POSSIBLE DEFORMATION...SO FORCING FOR PRECIP IS POSSIBLE PARTICULARLY IN THE ERN HALF OF THE FA. AS MENTIONED EARLIER WILL TREND GRIDS TOWARD THIS MORE OFFSHORE SOLN WITH THIS UPDATE...BUT CARRY POPS ACROSS THE ENTIRE REGION AS THERE ARE STILL SOME FACTORS THAT WILL HAVE TO BE IRONED OUT IN THE NEXT FEW DAYS. WILL ALSO CONTINUE TO SHOW SOME SNOWFALL POSSIBLE PARTICULARLY W OF THE I-495 AND I-95 CORRIDOR ALTHOUGH AMOUNTS WILL BE STRONGLY CORRELATED TO THE FINAL TRACK...WHICH REMAINS IN QUESTION. THU INTO EARLY WEEKEND... WITH SOME ISSUES REGARDING THE TRACK OF THE SFC LOW AND ITS ASSOCIATED WAVE THERE ARE STILL A FEW QUESTIONS REGARDING ANY FAST MOVING SHORTWAVES DIVING OVER SRN NEW ENGLAND IN THE NW FLOW. SUSPECT THAT MUCH OF THIS PERIOD WILL BE DRY AS MOST GUIDANCE SUPPORTS HIGH PRES BUILDING IN ESPECIALLY FRI. WILL LEAN ON A DRY COOL FORECAST GIVEN THE NW FLOW ATTM. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS IN THE WAKE OF A COLD FRONT THIS AFTERNOON. BKN-OVC CUMULUS CLOUDS AT 4000-5000 FT IN WESTERN AND CENTRAL PORTIONS THROUGH THIS AFTERNOON. W-NW WINDS GUSTING TO 20-30 KT. AN ISOLATED FLURRY POSSIBLE IN THE NRN BERKSHIRES AND EXTREME SWRN NH. VFR TONIGHT. KBOS TAF...MODERATE TO HIGH CONFIDENCE. VFR. GUSTS TO 20-30 KT THIS AFTERNOON INTO TONIGHT. KBDL TAF...HIGH CONFIDENCE. VFR. W-NW WINDS WITH GUSTS AROUND 25 KT INTO THIS EVENING. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... SUNDAY NIGHT THROUGH MONDAY...HIGH CONFIDENCE. VFR. MAYBE SOME MVFR CIGS IN THE ERN SLOPES OF THE BERKSHIRES. TUESDAY AND WEDNESDAY...LOW CONFIDENCE. MVFR/IFR CONDITIONS POSSIBLE IN POTENTIAL RA/SN/FZRA/SNPL...DEPENDENT ON THE TRACK OF LOW PRES. && .MARINE... MODERATE TO HIGH CONFIDENCE INTO SUNDAY... GALE WARNINGS HOISTED IN EXPECTATION OF STRONG W/NWLY FLOW IN WAKE OF THE COLD FRNT DEVELOPING BY MIDDAY WITH GUSTS AT OR EXCEEDING 34 KTS. WILL KEEP SMALL CRAFT ADVISORIES POSTED FOR THE INNER HARBORS AND BAYS. DUE TO THE STRONG W/NW FLOW...SEAS WILL BUILD TO 8 TO 10 FEET ACROSS THE OUTER WATERS INTO THIS EVENING. WINDS ALOFT INCREASE THIS EVENING AND TONIGHT. WILL BE EVALUATING TO SEE WHETHER GALE WARNINGS NEED TO BE EXTENDED TO THE INNER HARBORS AND BAYS. OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY... MODERATE CONFIDENCE THROUGH THE PERIOD. SEAS... SEAS DROP BRIEFLY BELOW 5 FT ESPECIALLY NEAR SHORE WATERS MON. HOWEVER...SWELL WILL HAVE LITTLE TIME TO SUBSIDE BELOW 5 FT THROUGH THE PERIOD ON THE OUTER WATERS. SO EXPECT AFTER BRIEF PERIOD OF DIMINISHING SEAS INTO MON THAT SWELL WILL ONCE AGAIN BUILD IN ADVANCE OF LOW PRES TUE INTO WED. WITH SEAS OF 5-8 FT POSSIBLE ONCE AGAIN BY MID WEEK. WINDS... SUN NIGHT INTO MON WINDS OF 20-25 KT ARE LIKELY. WINDS DIMINISH OVER THE WATERS TUE AND TUE NIGHT. HOWEVER A COASTAL STORM MAY BRING ANOTHER CHANCE FOR GALE FORCE WINDS /AT LEAST SMALL CRAFT LEVEL/ BY WED. OVERALL...VERY NARROW WINDOW FOR CONDITIONS BELOW SMALL CRAFT THRESHOLDS MON NIGHT INTO EARLY TUE. OTHERWISE...WHETHER IT BE SEAS OR WINDS...SMALL CRAFT ADVISORIES ARE LIKELY THROUGH MUCH OF THE PERIOD. THERE IS ALSO THE POSSIBILITY OF SOME GALES BY WED DEPENDING ON THE TRACK OF LOW PRES. && .FIRE WEATHER... MUCH COOLER AND DRIER AIR THIS AFTERNOON WITH W/NW WINDS GUSTING UP TO 30 MPH. WHILE WE HAVE NOT SEEN A DECENT RAINFALL SINCE NOVEMBER 13TH...AND STRONG WINDS ARE FORECAST...RELATIVE HUMIDITIES ARE ANTICIPATED TO REMAIN AT OR ABOVE THE 30 PERCENT THRESHOLD. THEREFORE WEATHER CONDITIONS WILL REMAIN JUST AT OR ABOVE CRITERIA FOR ISSUING FIRE WEATHER HEADLINES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ232>235-237-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ230-231-236- 251. GALE WARNING UNTIL 1 PM EST SUNDAY FOR ANZ250-254-255. && $$ SYNOPSIS...DOODY/SIPPRELL NEAR TERM...FIELD SHORT TERM...SIPPRELL LONG TERM...DOODY AVIATION...FIELD/SIPPRELL/DOODY MARINE...FIELD/SIPPRELL/DOODY FIRE WEATHER...FIELD/SIPPRELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
947 AM CST SAT NOV 24 2012 .DISCUSSION... 930 AM CST HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES IN PLACES. THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO 850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/. WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS. THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST. SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS DOWN 1 TO 3 DEGREES IN PLACES. MTF //PREV DISCUSSION... 352 AM CST FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS SUNDAY RETURNING TO AROUND SEASONAL NORMS. AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY... TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN SETS UP ACROSS THE AREA THIS EVENING. WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE. SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S. A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR BEHIND IT WILL REMAIN TO OUR NORTH. MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE ANOTHER MODEL RUN BEFORE PULLING COMPLETELY. A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS. THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * CEILINGS IN THE 2500-3000 FT RANGE THROUGH ABOUT 18Z...THEN BECOMING SCATTERED. * WEST TO NORTHWEST WIND 10 KT OR LESS GRADUALLY BECOMING MORE SOUTHWEST TO WEST BY LATE AFTERNOON. PAW //DISCUSSION...UPDATED 16Z... CLOUD DECK HAS BEEN SLOW TO ERODE FROM THE WEST THIS MORNING SO HAVE SLOWED DOWN THE IMPROVEMENT BY A COUPLE HOURS. MAY HAVE TO SLOW IT EVEN FURTHER. PREVIOUS DISCUSSION FROM 12Z... LOW PRESSURE CONTINUES TO DEPART THE REGION WITH AN AREA OF HIGH PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT LAKES FROM THE CENTRAL PLAINS. BETWEEN THE TWO SYSTEMS A STRATUS LAYER HAS REMAINED ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS EARLY THIS MORNING...AND WILL PERSIST THRU 16Z. THEN DRY WILL CONTINUE TO ERODE THE OVC CIGS...THINNING THE STRATUS DECK TO A SCT DECK ARND MID-MORNING. IN ADDITION WINDS WILL TURN W/SW BY MIDDAY/EARLY AFTN. THIS WILL ALLOW ADDTL DRY AIR TO FILTER INTO THE REGION...LIFTING THE BORDERLINE MVFR OR LOW END VFR CIGS TO ALL VFR CONDS. WINDS WILL THEN SLOWLY TURN S BY THIS EVE...HOWEVER REMAIN AT OR LESS THAN 10 KT. AFT 06Z SUN...THE GRADIENT BEGINS TO RETURN AND GUIDANCE SUGGESTS THAT WINDS WILL BEGIN TO INCREASE TOWARDS DAYBREAK SUN FROM THE S TO AROUND 10 TO 15 KT. OTHERWISE VFR CONDS WILL PREVAIL WITH JUST SOME MID-DECK CLOUDS ARND 8KFT AGL SLIDING OVERHEAD. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN WIND TREND. * HIGH CONFIDENCE IN CEILING TREND...MEDIUM CONFIDENCE IN TIMING. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 258 AM CST OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH. THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER WEAK LOW PRESSURE AND FRONTAL BOUNDARY. CONFIDENCE...MEDIUM/LOW. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
931 AM CST SAT NOV 24 2012 .DISCUSSION... 930 AM CST HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES IN PLACES. THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO 850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/. WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS. THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST. SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS DOWN 1 TO 3 DEGREES IN PLACES. MTF && .PREV DISCUSSION... 352 AM CST FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS SUNDAY RETURNING TO AROUND SEASONAL NORMS. AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY... TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN SETS UP ACROSS THE AREA THIS EVENING. WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE. SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S. A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR BEHIND IT WILL REMAIN TO OUR NORTH. MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE ANOTHER MODEL RUN BEFORE PULLING COMPLETELY. A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS. THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * CEILINGS IN THE 2500-3000 FT RANGE THROUGH 16Z...THEN BECOMING SCATTERED. * NORTHWEST WINDS AROUND 10 KT BECOMING WEST BY MIDDAY AND SOUTHWEST BY LATE AFTERNOON. PAW //DISCUSSION...UPDATED 12Z... LOW PRESSURE CONTINUES TO DEPART THE REGION WITH AN AREA OF HIGH PRESSURE SLOWLY BUILDING INTO THE WESTERN GREAT LAKES FROM THE CENTRAL PLAINS. BETWEEN THE TWO SYSTEMS A STRATUS LAYER HAS REMAINED ACROSS NORTHERN IL/NORTHWEST IN AIRFIELDS EARLY THIS MORNING...AND WILL PERSIST THRU 16Z. THEN DRY WILL CONTINUE TO ERODE THE OVC CIGS...THINNING THE STRATUS DECK TO A SCT DECK ARND MID-MORNING. IN ADDITION WINDS WILL TURN W/SW BY MIDDAY/EARLY AFTN. THIS WILL ALLOW ADDTL DRY AIR TO FILTER INTO THE REGION...LIFTING THE BORDERLINE MVFR OR LOW END VFR CIGS TO ALL VFR CONDS. WINDS WILL THEN SLOWLY TURN S BY THIS EVE...HOWEVER REMAIN AT OR LESS THAN 10 KT. AFT 06Z SUN...THE GRADIENT BEGINS TO RETURN AND GUIDANCE SUGGESTS THAT WINDS WILL BEGIN TO INCREASE TOWARDS DAYBREAK SUN FROM THE S TO AROUND 10 TO 15 KT. OTHERWISE VFR CONDS WILL PREVAIL WITH JUST SOME MID-DECK CLOUDS ARND 8KFT AGL SLIDING OVERHEAD. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN WIND TREND. * HIGH CONFIDENCE IN CEILING TREND...MEDIUM CONFIDENCE IN TIMING. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 258 AM CST OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH. THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER WEAK LOW PRESSURE AND FRONTAL BOUNDARY. CONFIDENCE...MEDIUM/LOW. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
503 AM CST SAT NOV 24 2012 .DISCUSSION... ISSUED 225 AM CST SAT NOV 24 2012 LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS. THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A STORM SYSTEM PASSES TO OUR SOUTH. SHORT TERM...TODAY THROUGH MONDAY NIGHT... LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD. RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET. TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY SHOULD BE ABOUT 10-15 DEGREES WARMER. LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST. FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA. LONG TERM...TUESDAY THROUGH FRIDAY... MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY. GEELHART && .AVIATION... ISSUED 503 AM CST SAT NOV 24 2012 A LARGE AREA OF MVFR CLOUDS IS AFFECTING BMI AND CMI THIS MORNING. BASED ON SATELLITE TRENDS...APPEARS THIS CLOUD DECK WILL NOT GET ANY FURTHER WEST THIS MORNING...THOUGH IT IS COMING CLOSE TO DEC AND PIA. MODELS DO NOT HAVE A GOOD HANDLE ON THIS LOW LEVEL MOISTURE AT THIS TIME...SO WILL TRY TO FORECAST CLEARING AT BMI AND PIA BASED ON SHIFTING OF HIGH PRSS RIDGE...WHICH SHOULD BE SOMETIME LATER THIS MORNING. SPI/PIA/DEC WILL REMAIN CLEAR THIS MORNING. ALL SITES WILL ALSO SEE AN INCREASE...AND LOWERING...OF MID CLOUDS THIS AFTERNOON...IN RESPONSE TO THE WAA THAT BEGINS TO RETURN THIS AFTERNOON ONCE THE HIGH PRSS RIDGE MOVES EAST OF THE AREA. ONCE THIS MOVES THROUGH...THE HIGH CIRRUS CLOUDS SHOULD BE THE RULE FOR THE NIGHT. WINDS WILL BE LIGHT WEST-NORTHWESTERLY THIS MORNING AND THEN BECOME SOUTH-SOUTHWESTERLY THIS AFTERNOON AND THEN CONTINUE INTO THE NIGHT. WINDS SPEEDS WILL NOT INCREASE TO AFTER 06Z LATE TONIGHT. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1032 AM EST SAT NOV 24 2012 .UPDATE... LATEST RADAR AND SURFACE OBSERVATIONS SHOW LITTLE MORE THAN FLURRIES ACROSS THE AREA THIS MORNING THANKS TO IMPRESSIVE DRY AIR ENTRAINMENT. CEILINGS ARE HOVERING AROUND 2500 FT WITH VERY DRY AIR ABOVE 5-6 KFT...SEVERELY LIMITING SNOW POTENTIAL. UPDATED FORECAST TO REMOVE ALL POPS AND TO EXPAND FLURRIES IN THE NORTHEAST. THIS RELATIVELY THIN LAYER OF STRATOCU HAS BEEN SLOW TO ERODE TO OUR SOUTHWEST THOUGH AND MADE SOME ADJUSTMENTS TO SKY COVER AS WELL. EXPECT CLOUDS AND FLURRIES WILL CONTINUE UNTIL LATE THIS AFTERNOON WHEN THE FLOW BECOMES INCREASINGLY ANTICYCLONIC WITH BUILDING MIDLEVEL HEIGHTS AND LARGE SCALE SUBSIDENCE. ALSO SHAVED A DEGREE OR TWO OFF HIGH TEMPS OWING TO MORE PESSIMISTIC CLOUD FORECAST. && .PREV DISCUSSION... /ISSUED 341 AM EST SAT NOV 24 2012/ SHORT TERM... FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT WILL BACK POPS OFF CONSIDERABLY. OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR TYPICAL LOCAL COLD SPOTS. UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED GREATER MIXING AND GAVE A +1 BUMP HIGHER. LONG TERM...MONDAY THROUGH FRIDAY MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM. ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE) SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH SHEARED WAVE(S). AVIATION... MVFR CONDS THIS MORNING WILL GRADUALLY IMPROVE INTO THIS AFTN W/CONTD LL DRY ENTRAINMENT. SIG SHSN AT KSBN LOOKING MORE AND MORE DOUBTFUL AND WILL MOST LIKELY BE DROPPED W/12Z ISSUANCE AS DRY AIR CLEARLY WINNING OUT SO FAR. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...T UPDATE...AGD
AREA FORECAST DISCUSSION
NWS DULUTH MN
637 AM CST SAT NOV 24 2012 .AVIATION.../12Z TAF ISSUANCE/ COLD NWLY FLOW WILL RESULT IN OCCASIONAL -SHSN AND IFR/MVFR CIGS....MAINLY AROUND KBRD AND KHYR THIS MORNING. A RIDGE OF HIGH PRESSURE WILL ALLOW FOR A BRIEF PERIOD OF CLEARING AS IT TRANSLATES ACROSS THE REGION TODAY. HOWEVER...THE NEXT LOW PRESSURE SYSTEM WILL QUICKLY DROP OUT OF CANADA AND INTO NORTHWEST MINNESOTA THIS AFTERNOON. THE LOW WILL SPREAD SNOW SHOWERS WITH LOWERING CEILINGS/VSBYS ACROSS THE FORECAST AREA THROUGH THE LATE AFTERNOON AND OVERNIGHT HOURS. THE LOWEST CIGS AND GREATEST SNOWFALL ACCUMULATION WILL BE ACROSS THE BORDERLAND AND INTO THE ARROWHEAD REGION...INCLUDING THE KINL AND KHIB TERMINALS. && .PREV DISCUSSION... /ISSUED 402 AM CST SAT NOV 24 2012/ SHORT TERM...TODAY THROUGH SUNDAY. AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES. THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE CLEAR AREAS. A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1 TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN. COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS. DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE. LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND. MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR. THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER. LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS IN THE NRN ZONES TUESDAY. && .POINT TEMPS/POPS... DLH 24 16 25 9 / 50 70 10 0 INL 25 14 20 8 / 80 70 10 10 BRD 26 17 25 7 / 20 30 10 0 HYR 27 17 29 10 / 20 60 10 0 ASX 28 20 31 16 / 30 70 10 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...DAP LONG TERM....GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS DULUTH MN
402 AM CST SAT NOV 24 2012 .SHORT TERM...TODAY THROUGH SUNDAY. AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES. THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE CLEAR AREAS. A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1 TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN. COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS. DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND. MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR. THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER. LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS IN THE NRN ZONES TUESDAY. && .AVIATION.../06Z TAF ISSUANCE/ COLD NWLY FLOW ALOFT WILL ALLOW INTERMITTENT BKN IFR/MVFR CIGS AROUND BRD/HIB/DLH TONIGHT WITH PERIODS OF LIGHT SNOW POSSIBLE. HYR WILL REMAIN UNDER LOW-END MVFR CIGS TONIGHT WITH FLURRIES. INL SHOULD REMAIN SKC WITH MUCH DRIER AIR TO THE NORTH. HIGH PRESSURE WILL MOVE ACROSS THE REGION TONIGHT AND AID IN THE CLEARING SOMEWHAT...BUT BE QUICKLY OVERTAKEN BY THE NEXT LOW PRESSURE SYSTEM MOVING IN FROM THE WEST BY EARLY FRI AFTERNOON. WILL SEE -SN DEVELOP AND CIGS DROP BY 20Z FRIDAY AROUND BRD/INL...AND SHORTLY AFTER AT HIB AND DLH. BEST CHC OF ACCUMULATING SNOW WILL BE ACROSS THE NORTH...WITH REDUCED IFR VSBYS POSSIBLE AS WELL EARLY FRI EVENING. WINDS SHOULD REMAIN LESS THAN 15 KTS. && .POINT TEMPS/POPS... DLH 24 16 25 9 / 50 70 10 0 INL 25 14 20 8 / 80 70 10 10 BRD 26 17 25 7 / 20 30 10 0 HYR 27 17 29 10 / 20 60 10 0 ASX 28 20 31 16 / 30 70 10 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...DAP LONG TERM....GRANING AVIATION...TENTINGER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
700 AM EST SAT NOV 24 2012 .SYNOPSIS... STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/... LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE- LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT 1130Z. THERE IS A CONNECTION FROM LAKE HURON JUST SOUTH OF KBUF AND INTO KELM. A SECOND WIDE/BROAD AREA OF CONVERGENCE TO THE SOUTH OF THAT FROM KJHW INTO THE NRN MTS. THE BETTER-ALIGNED FLOW IN THE LOW LEVELS WILL TRY TO MAKE THE PRECIP MORE BANDED THROUGH THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND SOME MEAGER DAYTIME HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY. THUS...THE CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR MOST OF THE AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A HURON CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS OR EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE OFF THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU MOVE OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED. && .SHORT TERM /5 PM THIS AFTERNOON THROUGH MONDAY/... THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT. HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL. THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY. THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT. FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT TERM PERIOD. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR PRECIP OVER C PA. HAVE NUDGED THE FORECAST FOR MON NITE-TUES NITE TOWARD THE CONGEALING CONSENSUS. THIS WILL PRETTY MUCH KEEP THE FORECAST A 30-50 PCT CHANCE OF PRECIP IN THAT TIME FRAME AND MAKE IT MORE SNOW P-TYPE THAN RAIN...SINCE A GENERALLY COLD SOLUTION IS MORE LIKELY WITH THE SFC LOW TRACK/TROUGH TO THE S OF THE AREA. NO CHANGES TO FCST FROM WED ONWARD. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... GUSTY WEST TO NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE EFFECT CLOUDS /STRATOCU/ TO MOST AIRFIELDS...THOUGH CIGS AFTER SUNRISE SHOULD GENERALLY BE VFR EXCEPT AT BFD AND JST WHERE THEY WILL REMAIN MVFR FOR SEVERAL HOURS THIS MORNING. FLURRIES AND ISOLD SNOW SHOWERS WILL FLOW OFF THE LAKES AS WELL...BUT ANY HEAVY ENOUGH TO CAUSE VSBY REDUCTIONS BELOW VFR SHOULD BE CONFINED TO BFD AND JST. IMPROVING CONDITIONS ARE EXPECTED THIS AFTERNOON THROUGH SUNDAY AS WINDS SHIFT MORE TO THE WEST THIS AFTERNOON AND EVENING AND THEN TO THE SW ON SUNDAY. OUTLOOK... SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE. MON- WED...VFR TO MVFR. CHC OF PCPN TUE-WED. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...DANGELO/TYBURSKI AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
648 AM EST SAT NOV 24 2012 .SYNOPSIS... STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/... LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE- LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT 1130Z. THERE IS A CONNECTION FROM LAKE HURON JUST SOUTH OF KBUF AND INTO KELM. A SECOND WIDE/BROAD AREA OF CONVERGENCE TO THE SOUTH OF THAT FROM KJHW INTO THE NRN MTS. THE BETTER-ALIGNED FLOW IN THE LOW LEVELS WILL TRY TO MAKE THE PRECIP MORE BANDED THROUGH THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND SOME MEAGER DAYTIME HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY. THUS...THE CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR MOST OF THE AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A HURON CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS OR EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE OFF THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU MOVE OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED. && .SHORT TERM /5 PM THIS AFTERNOON THROUGH MONDAY/... THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT. HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL. THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY. THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT. FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT TERM PERIOD. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR PRECIP OVER C PA. HAVE NUDGED THE FORECAST FOR MON NITE-TUES NITE TOWARD THE CONGEALING CONSENSUS. THIS WILL PRETTY MUCH KEEP THE FORECAST A 30-50 PCT CHANCE OF PRECIP IN THAT TIME FRAME AND MAKE IT MORE SNOW P-TYPE THAN RAIN...SINCE A GENERALLY COLD SOLUTION IS MORE LIKELY WITH THE SFC LOW TRACK/TROUGH TO THE S OF THE AREA. NO CHANGES TO FCST FROM WED ONWARD. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... GUSTY NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE EFFECT CLOUDS /STRATOCU/ TO MOST AIRFIELDS...AND SCT SNOW SHOWERS MAINLY TO THE HIER ELEVATIONS SITES. VSBY/CIG REDUCTIONS LIKELY AT BFD AND JST. BFD AND JST WILL BOUNCE BACK AND FORTH BETWEEN VFR AND MVFR EARLY THIS MORNING AS ROUNDS OF MAINLY LIGHT SNOW SHOWERS MOVE ACROSS. LATEST RADAR AND 11-3.9 SATELLITE IMAGERY SHOW LATEST ROUND OF THICKER CLOUDS REACHING LOWER SUSQ VALLEY...MDT/LNS...ATTM WITH EVEN AN ISOLD FLURRY PSBL...BUT NO REDUCTIONS EXPECTED. UNV AND AOO WILL SEE A FEW SNOW SHOWERS AND BRIEF MVFR CIGS AT TIMES. IMPROVING CONDITIONS ARE EXPECTED FOR SUNDAY AS WINDS SHIFT MORE TO THE WEST AND SW. OUTLOOK... SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE. MON-WED...VFR TO MVFR. CHC OF PCPN TUE-WED. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...DANGELO/TYBURSKI AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
502 AM EST SAT NOV 24 2012 .SYNOPSIS... STRONG NORTHWEST WINDS AND COLD AIR CROSSING THE GREAT LAKES WILL GENERATE LAKE EFFECT SNOW SHOWERS ACROSS THE WESTERN MOUNTAINS INTO TONIGHT. FAST WEST-NORTHWEST FLOW ALOFT WILL BRING A COUPLE OF WEAK LOW PRESSURE SYSTEMS ACROSS THE GREAT LAKES ON SUNDAY AND AGAIN MONDAY. A WEAK TROUGH OF LOW PRESSURE WILL FORM OVER THE LOWER MISSISSIPPI VALLEY ON MONDAY. AN AREA OF LOW PRESSURE COULD DEVELOP AND SLIDE PRECIPITATION INTO THE REGION FROM THE SOUTHWEST FOR MONDAY NIGHT INTO TUESDAY NIGHT. && .NEAR TERM /UNTIL 4 PM THIS AFTERNOON/... LAKE EFFECT SNOW ADVISORY CONTINUES FOR WARREN AND MCKEAN COUNTIES. A SLIGHT VEERING OF THE MEAN WIND HAS OCCURRED IN THE LOWER LAYERS THIS MORNING. THIS HAS CHANGED THE CHARACTER OF THE LAKE EFFECT SNOWS FROM THE EARLIER BROKEN CLUMP OF SHSN INTO MORE- LINEAR BANDS. HOWEVER...THERE IS LITTLE ORGANIZATION TO THEM AT 09Z. THERE IS THE BEGINNING OF A CONNECTION FROM LAKE HURON STARTING TO GO THROUGH KBUF WITH A SECOND WIDE/BROAD AREA OF CONVERGENCE TO THE SOUTH OF THAT INTO THE NRN MTS. THE BETTER- ALIGNED FLOW IN THE LOW LEVELS WILL HELP TO MAKE THE PRECIP MORE BANDED THROUGH THE DAY. BUT STRONG VERTICAL SPEED SHEAR AND MEAGER DAYTIME HEATING/MIXING WILL TRY TO COUNTERACT THAT TENDENCY. THUS...THE CONVECTION WILL BE MORE CELLULAR THAN TRUE BANDS FOR MOST OF THE AREA. THAT SAID...THE HIGH RES MODELS DO PLAY UP A HURON CONNECTION WHICH COULD STRING MOD SNOW INTO THE CENTRAL MTS OR EVEN THE POCONOS THIS AFTN. STILL...LITTLE ACCUMS ARE POSSIBLE OFF THE ALLEGHENY PLATEAU AS TEMPS RISE INTO THE U30S/L40S AS YOU MOVE OFF THE HIGHLANDS INTO THE SERN COS. THE SUBSIDENCE INVERSION REMAIN BELOW 7KFT AT KBFD ALL DAY PER THE RUC FCST SOUNDINGS. THE QPF REMAINS MEAGER WITH SREF AND DETERMINISTIC MODELS ALL MAKING BETWEEN A TENTH AND TWO TENTHS OF AN INCH OF LIQUID TODAY. SLR/S RUN GENERALLY 15:1 FOR THE DAY...BUT COULD BE 20:1 IN THE ADVY AREA AS THE TOP OF THE CLOUDS APPEAR TO STAY IN THE GOOD DENDRITIC GROWTH ZONE. THUS...WILL CONTINUE THE ADVY IN PLACE. HOWEVER...LOW LEVEL AIR IS VERY DRY AND CIGS HIGHER THAN WHAT WOULD NORMALLY BE EXPECTED FOR HEAVY SNOW. THIS AND THE TRANSIENT NATURE OF THE SHSN TODAY WILL LIMIT THE ACCUMS...AND NO EXPANSION OF THE ADVY IS NECESSARY. WINDS WILL MAKE IT FEEL VERY RAW...ESPECIALLY WITH RESPECT TO THE RECENT MILD WEATHER WE HAVE EXPERIENCED. && .SHORT TERM /4 PM THIS AFTERNOON THROUGH MONDAY/... THE NW FLOW CONTINUES INTO THE EVENING AND EARLY TONIGHT. HOWEVER...THE 8H TEMPS DO START TO TURN UPWARD AFTER MIDNIGHT. THE WINDS IN THE LOW LAYERS WILL BACK TO A MORE-SWRLY FLOW AS WELL. THIS SHOULD DWINDLE THE SHSN...BUT SOME MAY LINGER INTO SUNDAY. THE REAL ACCUMS SHOULD BE OVER BY MIDNIGHT. THE TOTALS BY THE END OF THE EVENT WILL STRUGGLE TO MEET ADVY NUMBERS EXCEPT IN THE FAR NWRN PART OF THE ADVY AREA...PLACES CLOSEST TO THE LAKE...DUE TO THE SHORT FETCH EXPECTED FOR MUCH OF THE EVENT. FLOW ALOFT REMAINS VERY FAST AND NWRLY ON SUNDAY. A CLIPPER-LIKE SHORTWAVE DROPS ACROSS THE LAKES ON SUNDAY AND WILL MAKE SOME SHSN IN THE NRN MTS AT THE NOSE OF SOME SLIGHT WAA. BUT THE GLANCING BLOW IS HARDLY WORTH ANY MORE OF A MENTION. A NEW SHOT OF COLD AIR MOVES DOWN FROM THE NW LATE MONDAY...BUT ANY MSTR ASSOCIATED WITH IT SHOULD GET DRIED UP...AND PROBABLY NOT ARRIVE AFTER THIS SHORT TERM PERIOD. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MODELS STILL HAVE SOME DIFFERENCES TO THE DEVELOPMENT OF A SYSTEM WHICH WILL LIKELY IMPACT THE REGION MON NITE INTO TUESDAY. WHILE THE 00Z ECMWF IS MORE GFS-LIKE NOW...THE OVERALL CONFIDENCE IN THE MED RANGE FORECAST HAS GROWN ONLY A SLIGHT BIT. A WEAK INVERTED TROUGH SHOULD DRAW MOISTURE NE FROM THE LOWER MS VALLEY MONDAY NIGHT AND DEEPEN A LITTLE LOW OVER THE SRN APP MTS MONDAY NIGHT/TUES. A GOOD DEAL OF QPF IS GENERATED TO THE NORTH OF THE TRACK OF THIS WEAK SFC LOW BACK INTO THE COLD AIR OVER PA. THE EC AND NAM SHOWS A WEAKER/FASTER LOW AND SHORTER TIME FRAME FOR PRECIP OVER C PA. WILL STICK WITH GOING FCST WITHOUT MUCH CHANGE IN FORECASTER CONFIDENCE. THIS WILL KEEP THE FORECAST A 30-50 PCT CHANCE OF PRECIP FROM MON NIGHT INTO TUESDAY NIGHT...AND CHC RA OR SN WORDING...BUT A GENERALLY COLD SOLUTION IS MORE LIKELY WITH THE SFC LOW TRACK/TROUGH TO THE S OF THE AREA. && .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/... GUSTY NORTHWEST WINDS WILL PERSIST TODAY...AND BRING LAKE EFFECT CLOUDS /STRATOCU/ TO MOST AIRFIELDS...AND SCT SNOW SHOWERS MAINLY TO THE HIER ELEVATIONS SITES. VSBY/CIG REDUCTIONS LIKELY AT BFD AND JST. BFD AND JST WILL BOUNCE BACK AND FORTH BETWEEN VFR AND MVFR EARLY THIS MORNING AS ROUNDS OF MAINLY LIGHT SNOW SHOWERS MOVE ACROSS. LATEST RADAR AND 11-3.9 SATELLITE IMAGERY SHOW LATEST ROUND OF THICKER CLOUDS REACHING LOWER SUSQ VALLEY...MDT/LNS...ATTM WITH EVEN AN ISOLD FLURRY PSBL...BUT NO REDUCTIONS EXPECTED. UNV AND AOO WILL SEE A FEW SNOW SHOWERS AND BRIEF MVFR CIGS AT TIMES. IMPROVING CONDITIONS ARE EXPECTED FOR SUNDAY AS WINDS SHIFT MORE TO THE WEST AND SW. OUTLOOK... SUN...SHSN/MVFR CIGS NW MTNS...VFR ELSEWHERE. MON-WED...VFR TO MVFR. CHC OF PCPN TUE-WED. && .CTP WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ004-005. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...DANGELO/TYBURSKI AVIATION...GARTNER/MARTIN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
436 PM EST SAT NOV 24 2012 .SYNOPSIS... COOL AND BLUSTERY CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. UNCERTAINTY REMAINS REGARDING THE TRACK AND INTENSITY OF A STORM TUESDAY AND WEDNESDAY. MUCH COLDER WEATHER IS EXPECTED BEHIND THE STORM LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 430 PM UPDATE... WINDS HAVE INCREASED LATE THIS AFTERNOON AS THE MIXING DEPTH GETS TO NEAR 850 MB. A GUST TO 44 KTS JUST OCCURRED AT WORCESTER AT 4 PM... WITH 32 KTS WAS REPORTED AT ORANGE MA AND 33 KTS AT PITTSFIELD AT 3 PM. THE NORTHWEST PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN UP THIS EVENING AND OVERNIGHT IN THE WAKE OF AN UPPER LEVEL TROUGH SWINGING ACROSS NORTHERN NEW ENGLAND. WINDS AT 3000-5000 FT OFF THE GROUND ARE FORECAST TO INCREASE TO 40-45 KNOTS OVERNIGHT. IT IS A TRICKY CALL FOR THE WINDS TONIGHT. BUFKIT SHOWS THAT DESPITE THE COLD AIR ADVECTION...THE WINDS DIMINISH TO 15 KT OVER MOST OF THE INTERIOR AS THE TEMPERATURE DROPS AND THE MIXING LEVEL IS NOT AS DEEP. A MAJOR EXCEPTION IS ALONG THE COAST...EVERYWHERE FROM CAPE ANN TO CAPE COD AND ON THE RI COAST...WHERE IT SHOULD REMAIN GUSTING TO 25 TO 30 KTS OVERNIGHT. FOR THE MOST PART...LAKE EFFECT SNOW SHOWERS HAVE BEEN CONFINED TO THE BERKSHIRES. HOWEVER...A LIGHT SPRINKLE WAS REPORTED AT 3 PM IN NASHUA NH... SO SOME OF THE PRECIPITATION IS HITTING THE GROUND. CANNOT RULE OUT A FLAKE OF SNOW MAINLY WEST OF THE CONNECTICUT RIVER THIS EVENING BUT ACTIVITY SHOULD DIMINISH WITH NIGHTFALL. THE RAP MODEL SHOWS NO PRECIPITATION AFTER 04Z. LOWS MAINLY IN THE UPPER TEENS TO MID 20S EXCEPT NEAR 30 ALONG THE IMMEDIATE SOUTH COAST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... SUNDAY... SHOULD BE RATHER SIMILAR TO TODAY. SUNSHINE SHOULD GIVE WAY TO A FAST MOVING BATCH OF MID LEVEL CLOUDINESS IN THE AFTERNOON LEADING TO PARTLY TO MOSTLY CLOUDY SKIES. USED A 50-50 BLEND OF GFS AND NAM FOR SKY GRIDS SINCE THEY DIFFERED ON THE TIMING OF THESE CLOUDS. IT WILL AGAIN BECOME WINDY WITH GUSTS TO 20 TO 30 KTS FROM MID MORNING THROUGH MID AFTERNOON AS THE MIXING INCREASES. WINDS SHOULD DIMINISH LATE IN THE AFTERNOON. HIGHS MAINLY IN THE 40S. SUNDAY NIGHT... BECOMING MOSTLY CLEAR WITH LIGHT WINDS AND LOWS 20-30. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... * COLDER...DRY WEATHER EXPECTED EARLY NEXT WEEK * A STORM IS LIKELY TO AFFECT THE AREA MID WEEK * COLDER WEATHER EXPECTED LATE NEXT WEEK 24/12Z MODELS ARE STARTING TO SHOW SOME CONSISTENCY THROUGHOUT THE LONG TERM PORTION OF THE FORECAST. THERE IS STILL PLENTY OF UNCERTAINTY REGARDING THE MID WEEK STORM...THOUGH THE 06Z GFS/00Z ECMWF/12Z GFS ALL HAVE SIMILAR SOLUTIONS WITH LOW PRESSURE MOVING OFF THE MID ATLANTIC COAST AND TRAVELING JUST SOUTH OF THE 40/70 BENCHMARK AND BRINGING SNOW TO MUCH OF THE AREA WITH A FOCUS ON THE SOUTHERN PORTIONS OF SOUTHERN NEW ENGLAND. HOWEVER...THE 12Z NAM /AN OUTLIER AT THIS POINT/ SIMPLY HAS HIGH PRESSURE OVER THE REGION AND NO INDICATION OF PRECIP AT ALL. WILL TREND TOWARD A ECMWF/GFS/HPC SOLUTION... HOWEVER...KEEPING IN MIND ALL THE FLIP FLOPPING AND UNCERTAINTY WILL ONLY TREND TOWARD IT. ASIDE FROM THE STORM...THE WEATHER IS FAIRLY QUIET BOTH EARLY AND LATE NEXT WEEK WITH NORTHWESTERLY FLOW BRINGING COLDER TEMPERATURES. MONDAY...STRONG NORTHWESTERLY FLOW WILL CONTINUE TO KEEP TEMPS SLIGHTLY BELOW NORMAL. HIGH PRESSURE BUILDS IN KEEPING MOSTLY CLEAR SKIES THROUGH THE DAY AND INTO THE EVENING. TUESDAY INTO WEDNESDAY...GIVEN THE NUMEROUS SOLUTIONS OVER THE LAST SEVERAL DAYS AM STILL HESITANT TO MAKE A RUN FOR A SINGLE SOLUTION. THAT SAID...THE ECMWF AND GFS HAVE STARTED TO FOCUS TOWARDS LOW PRESSURE ON A SOUTHERLY TRACK ALONG OR JUST SOUTH OF THE 40/70 BENCHMARK FOR WINTER STORMS. AT THIS POINT...THIS SOLUTION BRINGS HEAVY SNOW...LIKELY FOCUSED MORE ON THE SOUTHERN AREAS OF THE CWA MAINLY ON TUESDAY NIGHT INTO WEDNESDAY. THERE ARE STILL OTHER SOLUTIONS...THE NAM HAS HIGH PRESSURE OVER THE REGION TUESDAY. HOWEVER...AT THIS POINT...THE ECMWF/GFS SOLUTION APPEARS THE MOST LIKELY. WILL TREND TOWARD THIS SOLUTION...BUT CONFIDENCE IS STILL LOW. THURSDAY AND FRIDAY...DESPITE ALL THE DISCREPANCIES/UNCERTAINTY FOR EARLIER IN THE PERIOD...THESE TWO PERIODS HAVE FAIRLY GOOD AGREEMENT AMONGST THE MODELS. NORTHWESTERLY FLOW WITH THE COOLEST TEMPS OF THE SEASON THUS FAR MOVING IN ON STRONG COLD AIR ADVECTION. LOOKS LIKE A COLD AND BRISK END TO THE WEEK. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...MODERATE TO HIGH CONFIDENCE. VFR CONDITIONS THROUGH SUNDAY NIGHT. SCATTERED LIGHT SNOW SHOWERS SHOULD BE CONFINED TO BERKSHIRES THIS EVENING ALTHOUGH A FLAKE OR TWO CANNOT BE RULED OUT AS FAR EAST AS THE CONNECTICUT RIVER BEFORE 04Z. W-NW WINDS GUSTING TO 20-30 KTS MOST AREAS. WINDS MAY DIMINISH TO 15 KTS IN THE INTERIOR OVERNIGHT. WINDS DIMINISHING AGAIN IN THE LATE AFTERNOON SUNDAY EXCEPT ALONG THE COAST. KBOS TAF...MODERATE TO HIGH CONFIDENCE. VFR THROUGH SUNDAY NIGHT. W-NW WINDS WITH GUSTS TO 20-30 KT TONIGHT AND SUNDAY. KBDL TAF...HIGH CONFIDENCE. VFR THROUGH SUNDAY NIGHT. SLIGHT CHANCE OF A FLURRY THIS EVENING. W-NW WINDS WITH GUSTS 20-30 KT THIS EVENING AND AGAIN SUNDAY MID MORNING THROUGH MID AFTERNOON. OUTLOOK...MONDAY THROUGH THURSDAY... MONDAY...HIGH CONFIDENCE. VFR. TUESDAY THROUGH WEDNESDAY MORNING...LOW CONFIDENCE. MVFR/IFR CONDITIONS POSSIBLE IN POTENTIAL RA/SN/FZRA/SNPL. WEDNESDAY AFTERNOON THROUGH THURSDAY...MODERATE TO HIGH CONFIDENCE. VFR. && .MARINE... MODERATE CONFIDENCE INTO SUNDAY NIGHT... GALE WARNINGS CONTINUE FOR THE COASTAL WATERS INCLUDING NANTUCKET SOUND...EXCEPT FOR THE INNER HARBORS AND BAYS WHERE SMALL CRAFT ADVISORIES ARE POSTED. AS AN UPPER LEVEL SHORT WAVE TROUGH SWINGS THROUGH NORTHERN NEW ENGLAND OVERNIGHT...W TO NW WINDS WILL CONTINUE TO INCREASE OVER THE COASTAL WATERS...REACHING 35 KTS OVER THE GALE WARNING AREA AND CONTINUING INTO MUCH OF SUNDAY. THERE IS A CHANCE THAT A FEW GUSTS TO GALE FORCE COULD OCCUR CLOSER TO THE COAST IN THE SMALL CRAFT ADVISORY AREA...BUT FREQUENT GUSTS ARE NOT EXPECTED. ONE CONCERN IS A GUST TO 44 KTS AT WORCESTER AIRPORT RIGHT AT 4 PM... BUT WE ARE THINKING THAT THIS IS ELEVATIONAL AND STILL RELATED TO THE MAXIMUM MIXING OF THE AFTERNOON. WE WILL NEED TO WATCH THIS CLOSELY IN CASE GALES ARE NEEDED EVERYWHERE ALONG THE COAST OVERNIGHT. SEAS ARE FORECAST TO CONTINUE TO BUILD TO 8 TO 11 FEET ACROSS THE OUTER WATERS TONIGHT. WINDS SHOULD BEGIN TO DIMINISH TO BELOW GALE FORCE IN THE AFTERNOON BUT SMALL CRAFT ADVISORY LEVEL WIND GUSTS TO 25 KTS MAY CONTINUE OVER THE OUTER WATERS THROUGH SUNDAY NIGHT. SLOWLY SUBSIDING SEAS SUNDAY NIGHT. OUTLOOK...MONDAY THROUGH THURSDAY... MODERATE CONFIDENCE THROUGH THE PERIOD. SEAS WILL FALL BELOW 5 FEET LATE MONDAY AND REMAIN BELOW THROUGH LATE TUESDAY. THEN SEAS WILL BUILD AGAIN AS LOW PRESSURE APPROACHES THE WATERS LATE TUESDAY INTO WEDNESDAY AND REMAIN ABOVE 5 FEET THROUGH THE PERIOD. WINDS WILL REMAIN BELOW 25 KTS THROUGH TUESDAY. WINDS INCREASE TO 25 TO 30 KTS WEDNESDAY AND THURSDAY AS LOW PRESSURE MOVES ACROSS THE WATERS. LOW PROBABILITY OF GALES LATE WEDNESDAY INTO THURSDAY. && .FIRE WEATHER... NO HEADLINES ARE ANTICIPATED BUT FELT IT WAS WORTH MENTIONING THAT THE MINIMUM RELATIVE HUMIDITIES WILL BE DOWN AROUND 30 PERCENT SUNDAY AFTERNOON. WINDS WILL BE GUSTING TO 20 TO 30 MPH BUT WILL BE DIMINISHING IN THE MID TO LATE AFTERNOON AT THE TIME OF THE MINIMUM HUMIDITIES. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...GALE WARNING UNTIL 10 AM EST SUNDAY FOR ANZ232>235-237-256. SMALL CRAFT ADVISORY UNTIL 7 PM EST SUNDAY FOR ANZ230-231-236- 251. GALE WARNING UNTIL 1 PM EST SUNDAY FOR ANZ250-254-255. && $$ SYNOPSIS...RLG/GAF NEAR TERM...GAF SHORT TERM...GAF LONG TERM...RLG AVIATION...RLG/GAF MARINE...RLG/GAF FIRE WEATHER...GAF
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
407 PM CST SAT NOV 24 2012 .DISCUSSION... 234 PM CST THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START METEOROLOGICAL WINTER. THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE. MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE 20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN. TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S BY DAYBREAK ON SUNDAY. THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID- LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE. THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE 20S FOR LOWS. TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH. BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST. WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS TIME OF YEAR. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * NONE. BMD //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND MOVING TO THE EAST. THESE VFR-LEVEL CEILINGS WILL MOVE INTO ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES ACROSS THE AREA ON SUNDAY. PAW //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS. BMD //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT. THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY... WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE MIDWEST AND LAKES REGION MID WEEK. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
234 PM CST SAT NOV 24 2012 .DISCUSSION... 234 PM CST THE FORECAST CHALLENGES FOR TODAY ARE MAINLY TEMPERATURES AS READINGS LOOK TO WARM LATER THIS EVENING THROUGH THE DAY SUNDAY THEN A COOL DOWN INTO MONDAY...FOLLOWED BY A WARM-UP WITH WHAT LOOKS TO POTENTIALLY BE 50S TO END NOVEMBER AND START METEOROLOGICAL WINTER. THE STUBBORN CYCLONIC FLOW AND ITS PESKY STRATUS IS ON THE WAY OUT WITH A SURFACE RIDGE AXIS MOVING QUICKLY OVER THE AREA THIS EVE. MID-LEVEL WARM AIR ADVECTION CLOUDS ARE ALREADY SPREADING OVER THIS RIDGE ACROSS WESTERN IL AND SHOULD QUICKLY EXPAND EAST THROUGH THE EVE. BEFORE THE ARRIVAL OF THESE CLOUDS IN THE HOURS AFTER SUNSET...EASTERN AREAS SHOULD SEE TEMPERATURE DROPS THROUGH THE 20S GIVEN LIGHT WINDS. A GRADUAL CLIMB IN TEMPERATURES IS THEN EXPECTED AREA WIDE AS PRESSURE FALLS AND RETURN FLOW SPREAD IN. TEMPERATURES ARE LIKELY TO CLIMB BACK TO THE UPPER 20S TO MID 30S BY DAYBREAK ON SUNDAY. THE WARM AIR ADVECTION CLOUDS TONIGHT ARE ASSOCIATED WITH A STRONG UPPER LEVEL LOW MOVING EAST ACROSS NORTHERN SASKATCHEWAN AND MANITOBA...AND MORE SO WITH A RELATED PV ANOMALY AND SHORT WAVE EXTENDING SOUTHWARD. THIS WILL TRANSLATE INTO WI BY OVERNIGHT AND ALREADY TO THE EASTERN GREAT LAKES BY SUNDAY MORNING. SUPPORT FOR UPWARD MOTION DOES SPREAD THIS FAR SOUTH AS REFLECTED IN RAP AND NAM Q-VECTOR CONVERGENCE FIELDS. HOWEVER...SATURATION AND MID- LEVEL MOISTURE CONVERGENCE IS BETTER SITUATED TO THE NORTH. THIS DISJOINT WILL LIKELY KEEP PRECIPITATION TO THE NORTH...THOUGH FLURRIES COULD GET CLOSE TO THE WI/IL STATE LINE LATER THIS EVE. THE WARM SECTOR OF THIS CLIPPER-LIKE SYSTEM WILL CONTINUE OVER THE AREA INTO SUNDAY. THIS HAS OFFERED 40S TO THE WEST OF THE REGION IN NEBRASKA TODAY...AND ENVISION LOWER TO MID 40S DURING THE DAY SUNDAY HERE. AS THE COLD FRONT MOVES THROUGH...WINDS WILL TURN MORE NORTHWEST BY NIGHT AND TEMPERATURES WILL FALL BACK INTO THE 20S FOR LOWS. TRENDS CONTINUE TO SUPPORT THIS LOW-LEVEL COOL AIR AND RIDGING PUSH FROM THE NORTH TO EVOLVE THE PRIMARY BAROCLINIC ZONE TO THE SOUTH OF THE AREA ON MON NIGHT AND TUE...AND THUS KEEP THE PRIMARY FORCING FOR PRECIPITATION THERE AS WELL. AS THIS UNFOLDS THOUGH...THERE STILL IS A WINDOW FOR SMALL CHANCES OF LIGHT SNOW ACROSS THE SOUTHERN FORECAST AREA...MAINLY LATER MONDAY AFTERNOON AND NIGHT. THE SPREAD IN THE SREF AND GEFS MEMBERS IS NOW LOW OVER THE AREA...SO CONFIDENCE ON THIS IS FAIRLY HIGH. BEYOND THIS...TEMPERATURES WILL SLOWLY MODERATE THROUGH MID WEEK AS UPPER LEVEL RIDGING ACROSS THE WESTERN STATES EASES EAST. WITH A LARGE CLOSED LOW OFF THE WEST COAST FORECAST CONSISTENTLY BY GUIDANCE...THERE WILL BE LITTLE PROGRESSION OF MAJOR WEATHER SYSTEMS. A QUICK MOVING UPPER LEVEL JET MAX AND ASSOCIATED SHORT WAVE IS SEEN ON THU NIGHT/FRIDAY WITHIN THE SUITE OF LONG RANGE GUIDANCE. AGAIN THERE CONTINUES TO BE DECENT BUT SHORT-LIVED DYNAMICS FORECAST WITH THIS. HAVE INCREASED POPS SOME FROM A PROVIDED GUIDANCE BLEND. TEMPERATURE SPREAD BY DAYS 6 AND 7 IN THE FORECAST REALLY INCREASES IN GUIDANCE...SO CONFIDENCE DROPS...HOWEVER GUIDANCE IS FAVORING TEMPERATURES TO BE ABOVE NORMAL. ONE OF THE REASONS FOR SUCH SPREAD LOOKS TO BE CLOUD COVER...AS THE DETERMINISTIC GFS DRAGS UP QUITE A BIT OF LOW-LEVEL JUICE WITH THE THU NIGHT/FRI WAVE THAT MAY BE TOUGH TO SCOUR THIS TIME OF YEAR. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LIGHT SOUTHWEST TO WEST WIND. PAW //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES ACROSS THE AREA ON SUNDAY. PAW //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TREND. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT. THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY... WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE MIDWEST AND LAKES REGION MID WEEK. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
217 PM CST SAT NOV 24 2012 .DISCUSSION... 930 AM CST HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES IN PLACES. THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO 850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/. WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS. THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST. SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS DOWN 1 TO 3 DEGREES IN PLACES. MTF //PREV DISCUSSION... 352 AM CST FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS SUNDAY RETURNING TO AROUND SEASONAL NORMS. AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY... TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN SETS UP ACROSS THE AREA THIS EVENING. WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE. SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S. A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR BEHIND IT WILL REMAIN TO OUR NORTH. MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE ANOTHER MODEL RUN BEFORE PULLING COMPLETELY. A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS. THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LIGHT SOUTHWEST TO WEST WIND. PAW //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES ACROSS THE AREA ON SUNDAY. PAW //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TREND. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 217 PM...A RIDGE OF HIGH PRESSURE WILL PASS ACROSS LAKE MICHIGAN EARLY THIS EVENING AS LOW PRESSURE OVER SOUTHERN MANITOBA MOVES EAST ACROSS THE NORTHERN LAKES SUNDAY AND WEAKENS SUNDAY NIGHT. THE GRADIENT WILL TIGHTEN TONIGHT BETWEEN THE APPROACHING LOW AND THE WEAKENING RIDGE. WEST WINDS WILL SHIFT SOUTHWESTERLY THIS EVENING AND STEADILY INCREASE TO 15-25KTS BY LATE EVENING AND OVERNIGHT. SOME GUSTS TO 30 KTS ARE POSSIBLE ESPECIALLY OVER THE SOUTHERN PART OF THE LAKE WHERE THE GRADIENT WILL BE TIGHTEST. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE ACROSS THE LAKE SUNDAY AFTERNOON SHIFTING WINDS WESTERLY. AS ANOTHER AREA OF HIGH PRESSURE MOVES SOUTHEAST FROM THE NORTHERN PLAINS SUNDAY NIGHT TO THE SOUTHERN LAKES AND OHIO VALLEY MONDAY...THE GRADIENT WILL ONCE AGAIN TIGHTEN WITH NORTHWEST WINDS 20-25KTS EXPECTED. GRADIENT COULD BE STRONG ENOUGH FOR GUSTS TO 30KTS OVER NORTHERN LAKE MICHIGAN. AS THIS HIGH SETTLES SOUTH OF THE LAKE ON TUESDAY... WINDS WILL TURN SOUTHWESTERLY AND SHOULD RAPIDLY STRENGTHEN TUESDAY AFTERNOON AS ANOTHER LOW MOVES ACROSS ONTARIO AND THE NORTHERN LAKES WITH 30KTS AGAIN POSSIBLE OVER THE NORTHERN HALF OF THE LAKE. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE MIDWEST AND LAKES REGION MID WEEK. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
148 PM CST SAT NOV 24 2012 .DISCUSSION... 930 AM CST HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES IN PLACES. THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO 850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/. WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS. THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST. SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS DOWN 1 TO 3 DEGREES IN PLACES. MTF //PREV DISCUSSION... 352 AM CST FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS SUNDAY RETURNING TO AROUND SEASONAL NORMS. AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY... TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN SETS UP ACROSS THE AREA THIS EVENING. WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE. SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S. A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR BEHIND IT WILL REMAIN TO OUR NORTH. MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE ANOTHER MODEL RUN BEFORE PULLING COMPLETELY. A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS. THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LIGHT SOUTHWEST TO WEST WIND. PAW //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES ACROSS THE AREA ON SUNDAY. PAW //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN WIND TREND. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 258 AM CST OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH. THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER WEAK LOW PRESSURE AND FRONTAL BOUNDARY. CONFIDENCE...MEDIUM/LOW. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1157 AM CST SAT NOV 24 2012 .DISCUSSION... ISSUED 1030 AM CST SAT NOV 24 2012 UPDATED THE FORECAST TODAY FOR DECREASING LOW CLOUDS OVER EAST CENTRAL IL AND ALONG THE WABASH RIVER VALLEY IN SOUTHEAST IL TODAY. ALSO HAVE INCREASING MID/HIGHL CLOUDS OVER WESTERN AND CENTRAL IL DURING THIS AFTERNOON. SO VARIABLE CLOUD COVER ACROSS CENTRAL AND SE IL TODAY. ANOTHER CHILLY LATE FALL DAY WITH HIGHS IN THE MID TO UPPER 30S. BUT LIGHTER NW WINDS OF 5 TO 10 MPH TODAY AS HIGH PRESSURE RIDGE DRIFTS EAST FROM THE MS VALLEY ACROSS IL DURING THIS AFTERNOON. LOW STRATOCUMULUS CLOUD DECK WITH CEILING FROM 1500-2500 FT DRIFTED SOUTHWARD ACROSS EASTERN IL THIS MORNING AND CURRENTLY EXTEND ALONG AND EAST OF A LACON TO LINCOLN TO EFFINGHAM TO OLNEY LINE. THESE CLOUDS BLANKET MUCH OF IN/MI AND EASTERN WI TOO. MEANWHILE MID/HIGH CLOUDS ABOVE 8K FT WERE OVER MUCH OF IA/MO AND THE CENTRAL/NORTHERN PLAINS AND DRIFTING SE TOWARD WEST CENTRAL IL WITH CIRRUS CLOUDS 20-25K FT OVER MO AND SW IL. 10 AM TEMPS WERE IN THE MID TO UPPER 20S WITH OLNEY AND SPRINGFIELD UP TO 30F. DEWPOINTS WERE IN THE UPPER TEENS TO AROUND 20F. WNW WINDS LESS THAN 10 MPH PREVAILED THIS MORNING. 1031 MB HIGH PRESSURE OVER EAST TEXAS AND RIDGING ACROSS THE MS VALLEY WILL SETTLE ACROSS THE GULF COAST STATES BY 06Z/MIDNIGHT TONIGHT AND RIDGING NORTHWARD INTO THE TN/OH VALLEYS. RIDGE AXIS TO DRIFT EAST OF IL BY SUNSET WITH WNW WINDS UNDER 10 MPH TURNING SSW LATE TODAY AND EVENING. 850 MB TEMPS OF MINUS 4-6C AT 12Z MODIFY FROM SW TO NE DURING THE AFTERNOON REACHING MINUS 3C TO 1C BY SUNSET BUT LIMITED SURFACE WARM AIR ADVECTION PLUS SOME CLOUD COVER AND COLD START TO DAY WILL KEEP HIGHS IN THE MID TO UPPER 30S WITH MILDEST READINGS FROM SPRINGFIELD SW. 07 && .AVIATION... ISSUED 1155 AM CST SAT NOV 24 2012 MVFR BROKEN TO OVERCAST CEILINGS 1.5-2K FT FROM STRATOCUMULUS DECK OVER EASTERN IL AT CMI WILL SCATTERED OUT BY MID AFTERNOON AS DEC RECENTLY HAS SCATTERED OUT AND BMI WILL TOO IN THE NEXT HOUR. MEANWHILE BROKEN TO TO OVERCAST MID/HIGH CLOUDS ABOVE 8K FT OVER IA AND WEST CENTRAL IL WILL SPREAD INTO CENTRAL IL FROM WEST TO EAST DURING THE AFTERNOON AND REMAIN IN PLACE TONIGHT AND SUNDAY MORNING. AIRMASS QUITE DRY WITH DEWPOINTS IN THE UPPER TEENS TO AROUND 20F SO NO FOG EXPECTED NEXT 24 HOURS. THOUGH DEC HAD MVFR VSBYS 4-5 MILES WITH HAZE THIS MORNING BUT VSBY HAS RECENTLY ROSE TO 7 MILES. 1030 MB HIGH PRESSURE OVER EAST TX AND RIDGING ACROSS THE MS VALLEY WILL DRIFT EAST ACROSS THE SOUTHEAST STATES BY 18Z/NOON SUNDAY. WSW WINDS 5-9 KTS THIS AFTERNOON TO TURN SOUTH THIS EVENING AND THEN W/SW 9-13 KTS SUNDAY MORNING AS A WEAKENING FRONT MOVES INTO CENTRAL IL BY MIDDAY SUNDAY. 07 && .PREV DISCUSSION... ISSUED 225 AM CST SAT NOV 24 2012 LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS. THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A STORM SYSTEM PASSES TO OUR SOUTH. SHORT TERM...TODAY THROUGH MONDAY NIGHT... LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD. RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET. TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY SHOULD BE ABOUT 10-15 DEGREES WARMER. LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST. FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA. LONG TERM...TUESDAY THROUGH FRIDAY... MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1137 AM CST SAT NOV 24 2012 .DISCUSSION... 930 AM CST HAVE MADE SOME ADJUSTMENTS TO THE FORECAST TO HOLD ONTO CLOUDS LONGER...PARTICULARLY ACROSS NORTHEAST IL AND NORTHWEST IN...AND ACCORDINGLY HAVE LOWERED FORECAST HIGH TEMPS BY A COUPLE DEGREES IN PLACES. THE GOES WATER VAPOR LOOP THIS MORNING IS REFLECTING DRYING MOVING EASTWARD OVER THE AREA...AND REGIONAL SOUNDINGS REFLECTED THAT IN THE MID-LEVELS. HOWEVER...HEIGHT RISES AT 700 MB WERE NEUTRAL THIS MORNING INDICATING LIMITED OVERALL SUPPRESSION...AS WAS 700 TO 850 MB TEMPERATURE ADVECTION /DVN AND GRB EVEN COOLED AT 700 MB/. WITH PROFILERS ALSO INDICATING MORE OF A NORTHERLY FLOW IN THE LOW-LEVELS...GENERAL CYCLONIC FLOW APPEARS TO BE HANGING ON LONGER THAN INITIAL THOUGHT...ESPECIALLY ACROSS EASTERN AREAS. THIS REGIME WILL NOT AID THE CLOUDS IN CLEARING THROUGH EARLY AFTERNOON...EVEN WITH THE MOIST LAYER AT THE CLOUD HEIGHT REMAINING SHALLOW /1000 FT OR LESS/ ON AMDAR SOUNDINGS AND THE GRB RAOB THIS MORNING. ADAPTING AN AREA AMDAR SOUNDING IT WOULD SEEM THAT SURFACE TEMPS IN THE MID 30S WOULD BE NEEDED TO MIX OUT SOME OF THE CLOUD COVER...AND WITH NO WARMING HAPPENING UNDER THE HEART OF THE CLOUDS AND MUCH LOWER STARTING TEMPERATURES THIS MORNING AT THE PERIPHERY OF THE CLOUD SHIELD...DO NOT SEE THIS HAPPENING ANYTIME SOON. SO OUTSIDE OF A COUPLE HOLES FROM THE WEAK TO SUPPRESSION ALOFT...THE CLOUD SHIELD SHOULD ONLY OOZE ITS WAY EAST THROUGH EARLY AFTERNOON THEN INCREASE IN SPEED WITH THE WARM AIR ADVECTION PATTERN. EVEN AT 3 PM THOUGH...PARCEL TRAJECTORIES OVER EASTERN AREAS ARE FROM CLOUD COVERED SOUTH CENTRAL WI AT PRESENT. THE RAP 900 MB RH FORECAST SEEMS TO CAPTURE THE EVOLUTION WELL...AND IS IN GOOD AGREEMENT WITH THE NARRE-TL CLOUD FORECAST. SO HAVE COLLABORATED THESE IDEAS INTO THE CLOUD COVER FORECAST AND KEPT TEMPERATURES CLIMBING AT ABOUT 1 DEGREE PER TWO HOURS ACROSS THE EAST THROUGH EARLY AFTERNOON. OVERALL THIS TOOK HIGHS DOWN 1 TO 3 DEGREES IN PLACES. MTF //PREV DISCUSSION... 352 AM CST FOLLOWING AN ACTIVE HOLIDAY WEEK WITH DENSE FOG THANKSGIVING EVE MORNING FOLLOWED BY NEAR RECORD WARMTH ON THANKSGIVING DAY... AND THEN A JOLT BACK TO REALITY COURTESY OF A STRONG COLD FRONT ON BLACK FRIDAY... THE COMING WEEKEND WILL BE RELATIVELY QUIET WITH CHILLY DAYTIME HIGHS SATURDAY ONLY IN THE 30S... WITH MAX TEMPS SUNDAY RETURNING TO AROUND SEASONAL NORMS. AS DEEP SURFACE LOW PRESSURE OVER QUEBEC CONTINUES TO PUSH NE AWAY FROM THE GREAT LAKES... RIDGING WILL BUILD QUICKLY INTO NRN IL/NW IN THIS MORNING. THE STRENGTHENING ANTI-CYCLONIC FLOW COMBINED WITH INCREASED SUBSIDENCE THROUGH THE MID LEVELS SHOULD DRY OUT STUBBORN LINGERING SC FAIRLY QUICKLY FROM WEST TO EAST THROUGH THE MID MORNING HOURS. DESPITE SUNSHINE THROUGH THE REMAINDER OF THE DAY... TEMPS WILL ONLY RISE INTO THE MID 30S WITH COLD AIR AT 850 MB HANGING AROUND UNTIL THE BETTER WARM AID ADVECTION (WAA) PATTERN SETS UP ACROSS THE AREA THIS EVENING. WITH LOW LEVEL WAA COMBINED WITH RISING HEIGHTS ALOFT EXPECT MIN TEMPS TONIGHT TO BE REALIZED THIS EVENING WITH TEMPS THEN STEADYING OUT BY LATE EVENING AND PROBABLY EVEN RISING A FEW DEGREES DURING THE OVERNIGHT. EXPECT CLOUDS TO INCREASE AHEAD OF A FAIRLY POTENT SECONDARY SHORTWAVE TROUGH DROPPING INTO THE UPPER GREAT LAKES TONIGHT INTO EARLY SUNDAY. ANY FORCING OF CONSEQUENCE REMAINS NORTH OF THE LOCAL AREA HOWEVER AND HENCE EXPECT PRECIP TO DO LIKEWISE. SUNDAY SHAPING UP TO BE A FAIRLY TYPICAL LATE NOVEMBER DAY WITH CLOUDS GIVING WAY TO SOME SUN AND TEMPS TOPPING OUT IN THE MID 40S. A WEAK COLD FRONT ASSOCIATED WITH AFOREMENTIONED UPPER SHORTWAVE TROUGH WILL SWEEP ACROSS THE REGION DURING THE AFTERNOON BUT SHOULD RESULT IN LITTLE MORE THAN A WIND SHIFT AS COLDEST CORE OF AIR BEHIND IT WILL REMAIN TO OUR NORTH. MODELS CONTINUE TO TREND FARTHER SOUTH WITH LOW PRESSURE DEVELOPING OVER THE SOUTHERN PLANS ON MONDAY AND THEN TRACKING ACROSS THE LOWER MISSISSIPPI VALLEY MONDAY NIGHT AND ACROSS THE SOUTH ON TUES. WITH THIS TREND BECOMING MORE PRONOUNCED... WILL CONTINUE PREVIOUS FORECAST TREND OF LOWERING POPS ACROSS THE CWFA ANOTHER NOTCH FOR THE MON NIGHT-TUES TIME PERIOD. SHOULD THIS MORE SOUTHERN TRACK VERIFY... AT LEAST THE NORTHERN 2/3 OF THE CWFA IF NOT THE ENTIRE AREA WILL PROBABLY SEE NO PRECIP AT ALL... HOWEVER GIVEN SOME UNCERTAINTY REMAINING IN THE ENSEMBLE SPREAD... WOULD LIKE TO SEE ANOTHER MODEL RUN BEFORE PULLING COMPLETELY. A DRY NORTHWESTERLY FLOW ALOFT SETS UP FOR WED AND THURS WITH BROAD HIGH PRESSURE DOMINATING AT THE SURFACE AND SEASONAL TEMPS. THEN LEE SIDE CYCLOGENEIS DEVELOPS IN RESPONSE TO AN UPPER LEVEL TROUGH MOVING INTO THE CENTRAL PLAINS LATER ON THURSDAY AND MOVES INTO THE LOCAL AREA LATE THURSDAY NIGHT INTO FRIDAY. HAVE INTRODUCED LOW POPS WITH THIS FEATURE AS DYNAMICS INITIALLY APPEAR REASONABLY IMPRESSIVE HOWEVER AT DAYS 6-7 WOULD LIKE TO SEE GREATER MODEL CONSISTENCY BEFORE INTRODUCING MENTION OF ANYTHING MORE THAN A SLIGHT CHANCE OF PRECIP. THE AIR MASS IN PLACE AT THE TIME WILL BE SUFFICIENTLY COLD ENOUGH TO SUPPORT A MIX OF RAIN AND SNOW INITIALLY EARLY FRIDAY BEFORE INCREASING WAA WARMS THE COLUMN TO AT OR ABOVE THE FREEZING MARK. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LIGHT WEST WINDS BECOMING LIGHT SOUTHWEST BY LATE AFTERNOON. * CEILINGS AT 2500-3000 FT BECOMING SCATTERED CLOUDS BY 19Z. PAW //DISCUSSION...UPDATED 18Z... HIGH PRESSURE IS BUILDING INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA AT MIDDAY. THIS IS FINALLY ERODING THE CLOUD DECK THAT HAS PERSISTED THROUGH THE MORNING. HOWEVER THE CLEARING WILL BE SHORT LIVED AS MIDDLE AND HIGH LEVEL CLOUDS AHEAD OF AN APPROACHING UPPER LEVEL TROUGH ARE ALREADY INTO EASTERN IA AND MOVING TO THE EAST. THESE VFR-LEVEL WILL CEILINGS TO MOVE INTO ALL THE TERMINALS LATE THIS AFTERNOON INTO THE EVENING HOURS. THE TROUGH HAS LIMITED MOISTURE TO WORK WITH...SO NOT EXPECTING ANY PRECIPITATION WITH IT. THE BIGGEST IMPACT WILL BE TO SHIFT THE WINDS TO THE NORTHWEST AND SCATTER OUT THE CEILINGS AS IT MOVES ACROSS THE AREA ON SUNDAY. PAW //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN WIND TREND. * HIGH CONFIDENCE IN CEILING TREND AND TIMING. PAW //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...VFR. MONDAY...VFR. CHC OF LGT SN AND MVFR IN THE EVENING. TUESDAY...CHC OF MVFR EARLY...TRENDING VFR LATE. WEDNESDAY THROUGH THURSDAY...VFR. FRIDAY...VFR. SLIGHT CHC LGT RA/SN AND PATCHY MVFR. BEACHLER && .MARINE... 258 AM CST OCCASIONAL GALES CONTINUE ACROSS THE NORTHERN HALF OF LAKE MICHIGAN EARLY THIS MORNING...HOWEVER THE FREQUENCY CONTINUES TO DIMINISH. THUS IT APPEARS THE GALE WARNING WILL BE ALLOWED TO EXPIRE AT ISSUANCE OF THE NEW GLF. WILL MENTION AN OCCASIONAL GALE FORCE GUST TO 35 KT THROUGH DAYBREAK. THEN EXPECT WINDS TO STEADILY DIMINISH. HIGH PRESSURE WILL BEGIN TO BUILD IN FROM THE WEST...WHICH WILL ALLOW WINDS TO FURTHER DIMINISH AND BECOME WESTERLY THIS AFTERNOON. WILL CONTINUE TO FEATURE THE SMALL CRAFT ADVISORY THROUGH EARLY THIS AFTERNOON...POSSIBLY ENDING EARLIER FOR THE ILLINOIS NEARSHORE WATERS. WINDS WILL CONTINUE TO DIMINISH THROUGHOUT THE AFTERNOON AND EARLY EVENING...HOWEVER THE HIGH PRESSURE WILL QUICKLY DRIFT SOUTHEAST OF THE REGION. THIS WILL ALLOW ANOTHER TIGHT GRADIENT TO RETURN LATE TONIGHT WITH WINDS INCREASING FROM THE W/SW TO 15-25 KT. THIS WILL ALLOW WAVES ACROSS THE NORTHERN TIER OF LAKE MICHIGAN TO BUILD TONIGHT. THEN ANOTHER BOUNDARY WILL SLIDE ACROSS THE LAKE SUNDAY THAT WILL ONCE AGAIN ALLOW WINDS TO TURN NORTHWEST. WITH COLD AIR FLOWING OVER LAKE MICHIGAN...WAVES SHOULD EASILY BUILD LATER IN THE WEEKEND. THEN YET ANOTHER AREA OF HIGH PRESSURE APPEARS TO BUILD INTO THE REGION EARLY IN THE UPCOMING WEEK...WHICH SHOULD ALLOW WINDS TO DIMINISH MONDAY TO AROUND 10-20 KT BEFORE INCREASING AHEAD OF YET ANOTHER WEAK LOW PRESSURE AND FRONTAL BOUNDARY. CONFIDENCE...MEDIUM/LOW. BEACHLER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 PM SATURDAY. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1030 AM CST SAT NOV 24 2012 .DISCUSSION... ISSUED 1030 AM CST SAT NOV 24 2012 UPDATED THE FORECAST TODAY FOR DECREASING LOW CLOUDS OVER EAST CENTRAL IL AND ALONG THE WABASH RIVER VALLEY IN SOUTHEAST IL TODAY. ALSO HAVE INCREASING MID/HIGHL CLOUDS OVER WESTERN AND CENTRAL IL DURING THIS AFTERNOON. SO VARIABLE CLOUD COVER ACROSS CENTRAL AND SE IL TODAY. ANOTHER CHILLY LATE FALL DAY WITH HIGHS IN THE MID TO UPPER 30S. BUT LIGHTER NW WINDS OF 5 TO 10 MPH TODAY AS HIGH PRESSURE RIDGE DRIFTS EAST FROM THE MS VALLEY ACROSS IL DURING THIS AFTERNOON. LOW STRATOCUMULUS CLOUD DECK WITH CEILING FROM 1500-2500 FT DRIFTED SOUTHWARD ACROSS EASTERN IL THIS MORNING AND CURRENTLY EXTEND ALONG AND EAST OF A LACON TO LINCOLN TO EFFINGHAM TO OLNEY LINE. THESE CLOUDS BLANKET MUCH OF IN/MI AND EASTERN WI TOO. MEANWHILE MID/HIGH CLOUDS ABOVE 8K FT WERE OVER MUCH OF IA/MO AND THE CENTRAL/NORTHERN PLAINS AND DRIFTING SE TOWARD WEST CENTRAL IL WITH CIRRUS CLOUDS 20-25K FT OVER MO AND SW IL. 10 AM TEMPS WERE IN THE MID TO UPPER 20S WITH OLNEY AND SPRINGFIELD UP TO 30F. DEWPOINTS WERE IN THE UPPER TEENS TO AROUND 20F. WNW WINDS LESS THAN 10 MPH PREVAILED THIS MORNING. 1031 MB HIGH PRESSURE OVER EAST TEXAS AND RIDGING ACROSS THE MS VALLEY WILL SETTLE ACROSS THE GULF COAST STATES BY 06Z/MIDNIGHT TONIGHT AND RIDGING NORTHWARD INTO THE TN/OH VALLEYS. RIDGE AXIS TO DRIFT EAST OF IL BY SUNSET WITH WNW WINDS UNDER 10 MPH TURNING SSW LATE TODAY AND EVENING. 850 MB TEMPS OF MINUS 4-6C AT 12Z MODIFY FROM SW TO NE DURING THE AFTERNOON REACHING MINUS 3C TO 1C BY SUNSET BUT LIMITED SURFACE WARM AIR ADVECTION PLUS SOME CLOUD COVER AND COLD START TO DAY WILL KEEP HIGHS IN THE MID TO UPPER 30S WITH MILDEST READINGS FROM SPRINGFIELD SW. 07 && .AVIATION... ISSUED 503 AM CST SAT NOV 24 2012 A LARGE AREA OF MVFR CLOUDS IS AFFECTING BMI AND CMI THIS MORNING. BASED ON SATELLITE TRENDS...APPEARS THIS CLOUD DECK WILL NOT GET ANY FURTHER WEST THIS MORNING...THOUGH IT IS COMING CLOSE TO DEC AND PIA. MODELS DO NOT HAVE A GOOD HANDLE ON THIS LOW LEVEL MOISTURE AT THIS TIME...SO WILL TRY TO FORECAST CLEARING AT BMI AND PIA BASED ON SHIFTING OF HIGH PRSS RIDGE...WHICH SHOULD BE SOMETIME LATER THIS MORNING. SPI/PIA/DEC WILL REMAIN CLEAR THIS MORNING. ALL SITES WILL ALSO SEE AN INCREASE...AND LOWERING...OF MID CLOUDS THIS AFTERNOON...IN RESPONSE TO THE WAA THAT BEGINS TO RETURN THIS AFTERNOON ONCE THE HIGH PRSS RIDGE MOVES EAST OF THE AREA. ONCE THIS MOVES THROUGH...THE HIGH CIRRUS CLOUDS SHOULD BE THE RULE FOR THE NIGHT. WINDS WILL BE LIGHT WEST-NORTHWESTERLY THIS MORNING AND THEN BECOME SOUTH-SOUTHWESTERLY THIS AFTERNOON AND THEN CONTINUE INTO THE NIGHT. WINDS SPEEDS WILL NOT INCREASE TO AFTER 06Z LATE TONIGHT. AUTEN && .PREV DISCUSSION... ISSUED 225 AM CST SAT NOV 24 2012 LATEST SURFACE MAP SHOWING HIGH PRESSURE RIDGE EXTENDING FROM OKLAHOMA NORTHWARD INTO MINNESOTA. WIDESPREAD STRATOCUMULUS IN THE CYCLONIC FLOW OVER THE GREAT LAKES HAS PUSHED SOUTHWARD TO ABOUT A PONTIAC TO PARIS LINE AS OF 2 AM. LARGE SHIELD OF MID AND HIGH CLOUDS ALSO DROPPING SOUTHEAST FROM THE NORTHERN AND CENTRAL PLAINS. THE PRIMARY FORECAST CONCERN INVOLVES THE PRECIPITATION POTENTIAL MONDAY AND MONDAY NIGHT...INCLUDING ANY WINTER PRECIP TYPES...AS A STORM SYSTEM PASSES TO OUR SOUTH. SHORT TERM...TODAY THROUGH MONDAY NIGHT... LATEST RAP MODEL AND VAD WIND PROFILES AT 925 MB SUGGEST THE LOWER CLOUDS SHOULD NOT MAKE MUCH FURTHER WESTWARD PROGRESS...AND BEGIN TO PULL EASTWARD LATER THIS MORNING. HIGH CLOUDS STREAMING IN FROM THE NORTHWEST WILL YIELD PARTLY TO MOSTLY SUNNY CONDITIONS TODAY. TEMPERATURES EXPECTED TO REMAIN RATHER CHILLY TODAY WITH MID TO UPPER 30S COMMON...AS THE RIDGE AXIS MOVES OVERHEAD. RETURN FLOW EXPECTED TO BEGIN SETTING UP AROUND SUNSET. TEMPERATURES ACROSS THE WESTERN CWA EXPECTED TO LEVEL OFF BY MIDNIGHT...AND PERHAPS RISE A COUPLE DEGREES LATE. HIGHS ON SUNDAY SHOULD BE ABOUT 10-15 DEGREES WARMER. LARGE UPPER TROUGH OVER THE EASTERN CONUS TO BREAK DOWN THIS WEEKEND AS SOME AMPLIFICATION TAKES PLACE ALONG THE WEST COAST. FAST MOVING JET STREAK OF AROUND 75 KNOTS AT 500 MB WILL PUSH A BOUNDARY ACROSS THE CWA ON SUNDAY...BUT CLOUDS WILL BE THE MAIN EFFECT FROM IT. OF MORE CONCERN IS A STORM SYSTEM DEVELOPING ALONG THE TEXAS/OKLAHOMA BORDER LATE SUNDAY NIGHT AND MONDAY. WHILE THE EVENING MODELS ALL KEEP THE PARENT SURFACE LOW WELL TO OUR SOUTH...MOISTURE WILL BE DRAWN NORTH AS A SHORTWAVE IN THE NORTHERN JET STREAM MOVES INTO THE PLAINS. GFS/CANADIAN MODELS DRAW THE PRECIPITATION AS FAR NORTH AS ABOUT THE I-72 CORRIDOR BY MONDAY EVENING...WHILE THE NAM/ECMWF MODELS KEEP ALL THE PRECIP TO OUR SOUTH. THESE LATTER MODELS MAY BE A LITTLE ON THE FASTER SIDE...ESPECIALLY THE ECMWF...SO WILL LEAN MORE TOWARD THE SLOWER SOLUTIONS. AS SUCH...WILL HAVE THE HIGHEST POPS ACROSS THE SOUTHEAST CWA...ESPECIALLY MONDAY AFTERNOON AND NIGHT. FORECAST SOUNDINGS INDICATE A RAIN TO SNOW TRANSITION MONDAY EVENING ACROSS THE SOUTHEAST CWA AND LIGHT SNOW ELSEWHERE...BUT A PERSISTENT DRY NORTHEAST FLOW WILL KEEP PRECIP TOTALS DOWN. HAVE KEPT AREAS NORTHWEST OF THE ILLINOIS RIVER WITH MAINLY SLIGHT CHANCE POPS...WHERE HIGH PRESSURE WILL BUILD IN TO THE AREA. LONG TERM...TUESDAY THROUGH FRIDAY... MAINLY QUIET CONDITIONS EXPECTED DURING THIS TIME FRAME. UPPER RIDGING OVER THE WESTERN U.S. SHOULD TRANSITION TO MORE OF A ZONAL FLOW AS THE WEEK PROGRESSES...WITH MODERATING TEMPERATURES. LONGER RANGE MODELS PUSH A FAST MOVING SHORTWAVE THROUGH THE STATE LATE THURSDAY NIGHT OR EARLY FRIDAY. THE GFS IS THE WETTER OF THE MODELS WITH THIS FEATURE BUT MAINLY KEEPS THE PRECIPITATION JUST TO OUR NORTH...SO WILL KEEP THE EXTENDED FORECAST DRY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
545 PM EST SAT NOV 24 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 324 PM EST SAT NOV 24 2012 DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY. && .NEAR TERM /TONIGHT/... ISSUED AT 324 PM EST SAT NOV 24 2012 TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION. STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST. ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA. TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY... MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH. WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON MONDAY NIGHT. HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH... COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW TENTHS ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS EAST AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA FOR MIDWEEK. TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT... THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO OVERDO THE COLD AIR INTRUSION. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS. INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW. && .AVIATION /DISCUSSION FOR THE 25/0000Z TAF ISSUANCE/... ISSUED AT 545 PM EST SAT NOV 24 2012 STRATOCU DECK SHOULD BE NORTHEAST OF THE TAF SITES BY ISSUANCE TIME PER MODEL 925 MILLIBAR RH PROGS. MEANWHILE...THICK HIGH AND MID CLOUDS WILL ALSO BE MOVING IN FROM THE WEST AND COVER THE SKY THROUGH THE REMAINDER OF THE TAF PERIOD. SOUTH AND SOUTHWEST WINDS 5 KNOTS OR LESS WILL INCREASE TO NEAR 10 KNOTS TOWARD 12Z AND 15 KNOTS AFTER 15Z WITH GUSTS TO 20 KNOTS OR MORE. WINDS WILL THEN DIMINISH TO LESS THAN 10 KNOTS AND BECOME SOUTHWEST AND WEST AFTER 21Z BEHIND A DRY COLD FRONT. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....TDUD AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
330 PM EST SAT NOV 24 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 324 PM EST SAT NOV 24 2012 DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY. && .NEAR TERM /TONIGHT/... ISSUED AT 324 PM EST SAT NOV 24 2012 TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION. STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST. ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA. TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY... MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH. WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON MONDAY NIGHT. HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH... COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW TENTHS ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS EAST AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA FOR MIDWEEK. TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT... THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO OVERDO THE COLD AIR INTRUSION. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS. INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW. && .AVIATION /DISCUSSION FOR THE 24/2100Z TAF UPDATE/... ISSUED AT 330 PM EST SAT NOV 24 2012 PERSISTENT STRATOCU DECK IS KEEPING CEILINGS AT MVFR CATEGORY AT THE SITES AND SHOULD REMAIN THAT WAY THROUGH LATE AFTERNOON /23Z/ WHEN THE CLOUDS SHOULD SCATTER OUT AND RETURN TO VFR CONDITIONS. AS LOW LEVEL CLOUDS START TO SCATTER...HIGH CLOUDS WILL THEN START FILTERING INTO TAF SITES THIS EVENING AHEAD OF AN APPROACHING COLD FRONT. THIS WILL NOT IMPACT TAF SITES THOUGH...AND CONDITIONS WILL REMAIN AT VFR CATEGORY FOR THE REMAINDER OF TAF PERIOD. WINDS WILL BACK TO THE SOUTHWEST THIS EVENING AND BE SUSTAINED AT 3 TO 6 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....TDUD AVIATION...TDUD/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
324 PM EST SAT NOV 24 2012 .UPDATE... THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 324 PM EST SAT NOV 24 2012 DRY CONDITIONS WILL PERSIST INTO MONDAY AS HIGH PRESSURE PASSES TO THE SOUTH OF THE REGION. A SURFACE LOW WILL TRACK ALONG A REMNANT COLD FRONT THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. MOISTURE ASSOCIATED WITH THE LOW WILL LOFT INTO THE REGION...BRINGING CLOUDS AND LIGHT RAIN CHANGING TO SNOW. COLD DRY WEATHER WILL RETURN FOR MUCH OF THE REST OF THE WEEK AS BROAD HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY. && .NEAR TERM /TONIGHT/... ISSUED AT 324 PM EST SAT NOV 24 2012 TEMPS HAVE BEEN HELD DOWN SO FAR TODAY AS EXTENSIVE STRATOCU DECK REMAINS ACROSS MOST OF THE FORECAST AREA. AT 19Z...TEMPERATURES RANGED FROM THE UPPER 20S TO LOWER 30S ACROSS THE REGION. STRATOCU DECK IS THE INITIAL FOCUS OF THE FORECAST. VISIBLE SATELLITE SHOWING EROSION OF THE STRATOCU ACROSS THE WABASH VALLEY OVER THE LAST HOUR OR TWO AS LOW LEVEL FLOW BACKING IN RESPONSE TO THE ARRIVAL OF THE RIDGE AXIS. EXPECT LOW CLOUDS TO GRADUALLY THIN FROM THE WEST THROUGH THE REMAINDER OF THE AFTERNOON WITH SOME SUNSHINE ANTICIPATED WEST OF I-65 PRIOR TO SUNSET. FURTHER EAST...STRATOCU APPEARS MORE FIRMLY ENTRENCHED ON BACK SIDE OF DEEP UPPER TROUGH. HAVE TRENDED TOWARDS RAP 900-925MB RH PROGS WHICH KEEP CLOUDS INTO THE EVENING BEFORE THEY GIVE WAY FROM THE WEST. ANY CLEARING HOWEVER IS LIKELY TO BE TEMPORARY ACROSS THE FORECAST AREA AS MID AND HIGH LEVEL CLOUDS ARE ALREADY RAPIDLY EXPANDING EAST ACROSS THE MID MISSISSIPPI VALLEY AND WILL ENCOMPASS THE REGION OVERNIGHT. DEEP MOISTURE PRESENT ABOVE 600MB AFTER MIDNIGHT WITH ISENTROPIC LIFT NOTED AT 300K AND HIGHER ALL SUGGESTIVE OF FAIRLY DENSE CLOUD COVER LATE TONIGHT...ESPECIALLY OVER THE NORTHERN HALF OF THE FORECAST AREA. TEMPS...ENDED UP NEAR MAVMOS FOR LOWS OVERNIGHT AS COOLER THAN EXPECTED TEMPS TODAY COUNTERACT POTENTIAL FOR TEMPS TO STAY UP WITH CLOUDS TONIGHT. SHOULD END UP IN THE MID 20S MOST PLACES OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES AND TYPE WITH SURFACE WAVE TRACKING THROUGH THE TENNESSEE VALLEY MONDAY NIGHT. COLD FRONT WILL DROP SOUTH INTO THE REGION DURING THE DAY SUNDAY... MAINTAINING MID AND HIGH LEVEL CLOUDS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODEL SOUNDINGS CONTINUE TO SHOW AN AXIS OF DEEP MOISTURE ABOVE 10KFT AHEAD OF THE FRONT...GRADUALLY SHIFTING NORTH BY LATE AFTERNOON AND EVENING AS MOISTURE PROFILES DECREASE AND BOUNDARY LOSES ITS SURFACE CHARACTERISTICS AS IT SLIDES SOUTH. WHATS LEFT OF THE BOUNDARY WILL SHIFT SOUTH OF THE OHIO RIVER ON MONDAY AND BECOME NEARLY STATIONARY AS A SURFACE WAVE DEVELOPS OVER TEXAS AND TRACKS NORTHEAST ALONG IT. MODEL CONSENSUS OVER THE LAST COUPLE DAYS CONTINUE TO SHIFT THE TRACK OF THE LOW AND POSITION OF THE BOUNDARY STEADILY SOUTH INTO THE TENNESSEE VALLEY BY LATE MONDAY...LIKELY DUE AS MODELS CAPTURE THE STRENGTH OF THE APPROACHING HIGH OVER THE NORTHERN PLAINS TO A GREATER DEGREE. THE FURTHER SOUTH TRACK TO THIS SYSTEM IS PRESENTING SOME CHANGES NOT ONLY IN THE AMOUNT OF PRECIPITATION BUT ALSO IN POTENTIAL PRECIP TYPE AS COLDER AIR FILTERS INTO CENTRAL INDIANA MUCH QUICKER ON MONDAY NIGHT. HAVE LEANED TOWARDS THE CONSENSUS APPROACH BEING OFFERED BY THE ECMWF/OP GFS/SREF WHICH BRING THE MOISTURE PLUME NORTH INTO THE OHIO VALLEY LATE MONDAY AFTERNOON AHEAD OF THE UPPER LEVEL TROUGH AND NORTH OF THE SURFACE WAVE...SPREADING EAST ACROSS THE REGION MONDAY NIGHT. BEST ISENTROPIC LIFT NOW CONFINED TO MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA MONDAY NIGHT...AND EXPECT THE MOST WIDESPREAD PRECIPITATION WILL SET UP FROM FAR SOUTHERN COUNTIES SOUTH INTO KENTUCKY. FURTHER NORTH WHERE MOISTURE PROFILES ARE NOT AS IMPRESSIVE...EXPECT LIGHTER PRECIP TO THE TUNE OF LESS THAN A TENTH OF AN INCH. ANALYSIS OF MODEL SOUNDINGS AND LOW LEVEL THICKNESSES SUGGESTIVE OF MAINLY LIGHT SNOW ALONG AND NORTH OF I-70 MONDAY EVENING...WITH RAIN GRADUALLY MIXING WITH AND CHANGING OVER TO LIGHT SNOW FURTHER SOUTH AS THE NIGHT WEARS ON. SOME HINTS OF A BAND OF ENHANCED PRECIP SETTING UP NEAR OR JUST SOUTH OF THE FORECAST AREA LATE MONDAY NIGHT AND SHOULD THE COLDER AIR ARRIVE FAST ENOUGH... COULD SEE A QUICK BURST OF SNOW WITH A POSSIBLE ACCUM OF A FEW TENTHS ACROSS FAR SOUTHERN COUNTIES BEFORE THE BETTER LIFT SHIFTS EAST AROUND DAYBREAK TUESDAY. WITH THE CONSISTENT SHIFT SOUTH OF THE TRACK OF THE SURFACE LOW THE LAST FEW DAYS...CONFIDENCE IS LOW ON WHETHER THAT BAND OF ENHANCED PRECIP WILL SET UP OVER FAR SOUTHERN COUNTIES OR IF ITS CLOSER TO THE OHIO RIVER. ANY LINGERING PRECIP WILL END TUESDAY MORNING AS THE BROAD HIGH PRESSURE SHIFTS EAST INTO THE REGION. COLD DRY WEATHER WILL THEN RESUME FOR CENTRAL INDIANA FOR MIDWEEK. TEMPS...LEANED TOWARDS COOLER MAVMOS FOR SUNDAY WITH POTENTIAL FOR MORE CLOUDS ACROSS THE REGION. UNDERCUT MOS ON MONDAY WITH INCREASING CLOUDS AND NORTHERLY FLOW AND AGAIN TUESDAY WITH COLD ADVECTION IN WAKE OF THE STORM SYSTEM. NEAR MOS FOR LOWS TONIGHT... THEN WENT ABOVE GUIDANCE FOR MONDAY NIGHT WITH MOS APPEARING TO OVERDO THE COLD AIR INTRUSION. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... ISSUED AT 324 PM EST SAT NOV 24 2012 HIGH PRESSURE WILL BE IN CONTROL FOR THE MAJORITY OF THE EXTENDED PERIOD RESULTING IN A COOL/DRY AIRMASS OVER CENTRAL INDIANA. TEMPS WILL GRADUALLY WARM THROUGH THE COURSE OF THE PERIOD...AND INITIALIZATION HAS A GOOD HANDLE ON IT...SO NO DEVIATIONS. INITIALIZATION IS HINTING AT SOME PRECIP OVER THE NORTHERN PORTIONS OF THE FORECAST AREA AT THE END OF THE PERIOD AS AN UPPER LEVEL SHORTWAVE TRAVERSES CENTRAL INDIANA. THERE ARE A LOT OF DISCREPANCIES IN THE MODELS AT THIS TIME THOUGH...SO WILL NOT MAKE ANY CHANGES TO LATEST PRECIP INITIALIZATION. THE EURO AND GEM BARELY HINT AT THE SHORTWAVE ON THURSDAY NIGHT/FRIDAY MORNING...WHILE THE GFS SHOWS A SOMEWHAT DEVELOPED UPPER LEVEL LOW. && .AVIATION /DISCUSSION FOR THE 24/1800Z TAF ISSUANCE/... ISSUED AT 1230 PM EST SAT NOV 24 2012 PERSISTENT STRATOCU DECK IS KEEPING CEILINGS AT MVFR CATEGORY AT KBMG AND KHUF AND SHOULD REMAIN THAT WAY THROUGH LATE AFTERNOON. AFTER THAT...KBMG AND KHUF WILL RETURN TO VFR CONDITIONS. MEANWHILE...KIND AND KLAF HAVE ALREADY REACHED VFR CATEGORY BUT REMAIN OVERCAST. AS LOW LEVEL CLOUDS START TO SCATTER...HIGH CLOUDS WILL THEN START FILTERING INTO TAF SITES THIS EVENING AHEAD OF AN APPROACHING COLD FRONT. THIS WILL NOT IMPACT TAF SITES THOUGH...AND CONDITIONS WILL REMAIN AT VFR CATEGORY FOR THE REMAINDER OF TAF PERIOD. WINDS WILL BACK TO THE SOUTHWEST THIS EVENING AND BE SUSTAINED AT 3 TO 6 KTS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....TDUD AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1221 PM EST SAT NOV 24 2012 .AVIATION... CEILINGS WILL GRADUALLY IMPROVE THROUGH THE AFTERNOON AS DRIER AIR WORKS INTO THE REGION AND LOW LEVEL WINDS BACK TO A MORE SOUTHWESTERLY DIRECTION. THIS WILL TAKE SOME TIME THOUGH WITH PERSISTENT CYCLONIC FLOW OVER THE AREA. STRATOCU DECK WILL SCATTER COMPLETELY BY LATE THIS EVENING WITH VFR CONDITIONS CONTINUING THROUGH THE REST OF THE PERIOD. A PASSING SHORTWAVE TROUGH WILL BRING AN INCREASE IN MIDLEVEL CLOUDS ASSOCIATED WITH WAA ALOFT BUT CEILINGS WILL STAY WELL ABOVE 5 KFT. && .PREV DISCUSSION... /ISSUED 1032 AM EST SAT NOV 24 2012/ UPDATE... LATEST RADAR AND SURFACE OBSERVATIONS SHOW LITTLE MORE THAN FLURRIES ACROSS THE AREA THIS MORNING THANKS TO IMPRESSIVE DRY AIR ENTRAINMENT. CEILINGS ARE HOVERING AROUND 2500 FT WITH VERY DRY AIR ABOVE 5-6 KFT...SEVERELY LIMITING SNOW POTENTIAL. UPDATED FORECAST TO REMOVE ALL POPS AND TO EXPAND FLURRIES IN THE NORTHEAST. THIS RELATIVELY THIN LAYER OF STRATOCU HAS BEEN SLOW TO ERODE TO OUR SOUTHWEST THOUGH AND MADE SOME ADJUSTMENTS TO SKY COVER AS WELL. EXPECT CLOUDS AND FLURRIES WILL CONTINUE UNTIL LATE THIS AFTERNOON WHEN THE FLOW BECOMES INCREASINGLY ANTICYCLONIC WITH BUILDING MIDLEVEL HEIGHTS AND LARGE SCALE SUBSIDENCE. ALSO SHAVED A DEGREE OR TWO OFF HIGH TEMPS OWING TO MORE PESSIMISTIC CLOUD FORECAST. PREV DISCUSSION... /ISSUED 341 AM EST SAT NOV 24 2012/ SHORT TERM... FAILED LES RESPONSE ALG WRN PERIPHERY OF LK MI SO FAR OWING TO DEGREE OF DRY ENTRAINMENT ONGOING OUT OF WI. MOST FVRBL LK SP FETCH PRECONDITIONING 2 INTENSE BANDS ACRS NRN LWR STRETCHING SEWD INTO THE THUMB. SOME INDICATION IN RECENT RADAR IMAGERY OF WK BANDING DVLPG ALG A KMKG-KBIV LINE AND IF THAT INDEED DVLPS AS RUC SOLUTIONS SUGGEST THAT CONTD SHALLOW BNDRY LYR VEERING SHLD ALLOW THAT TO SAG SWD THROUGH MID MORNING. HWVR GIVEN THE DEARTH OF ADDNL MSTR ALOFT WILL BACK POPS OFF CONSIDERABLY. OTHERWISE CONTD QUITE COLD TDA W/LG AREA OF STRATO CU LOCKED IN BENEATH FAIRLY SHARP LL INVERSION. FLW BACKS LT AFTN WHICH WILL ERODE SWRN EDGE AND PROMOTE LIMITED INSOLATION BUT CONSIDERED TOO LATE TO APPRECIABLE PROMOTE MORE OF A DIURNAL RESPONSE. GREATER CLRG XPCD GOING INTO THIS EVENING AHD OF INCOMING HIGH CLD SHIELD ASSOCD/W FAST MOVING DISTURBANCE OVR SWRN CANADA. LOSS OF DEEPER SC UNDERNEATH ENVELOPING BUT THIN HIGH CLD SHIELD PERPLEXING GIVEN COLD MOS GUIDANCE IN LIGHT OF SWRLY RTN FLW DVLPG ON BACKSIDE OF DEPARTING RIDGE AXIS. THUS WILL ONLY MAKE SLIGHT ADJUSTMENTS FOR TYPICAL LOCAL COLD SPOTS. UPSTREAM SYS WILL DEAMPLIFY QUICKLY SEWD ON SUN. WAA AHD OF THIS FTR AND PARTIAL SUN WILL YIELD A BTR DIURNAL RESPONSE W/ANTICIPATED GREATER MIXING AND GAVE A +1 BUMP HIGHER. LONG TERM...MONDAY THROUGH FRIDAY MAIN FOCUS REMAINS ON DWINDLING CHANCES FOR SNOW WITH SYSTEM NOW PROGGED TO TRACK THROUGH THE TN/OH VALLEYS LATE MONDAY AFTERNOON THROUGH TUESDAY MORNING. 12/00Z GFS/GEFS/GEM ITERATIONS HAVE ALL TRENDED TOWARD THE LESS AMPLIFIED AND THEREFORE FARTHER SOUTH SOLUTION OF THE ECMWF WITH A SFC LOW TRACK FROM THE SOUTHERN PLAINS EAST THROUGH THE TN VALLEY. THIS SOUTHERLY TRACK WOULD RESULT IN DRY/COLD CONDITIONS LOCALLY WITH SFC HIGH PRESSURE BUILDING INTO THE SOUTHERN GREAT LAKES. HOWEVER...WOULD NOT BE SURPRISED TO SEE MODELS TREND BACK A LITTLE TO THE NORTH AND MORE AMPLIFIED WITH THIS POSITIVE PV ANOMALY AS IT DROPS SOUTHEAST INTO THE MIDWEST. INITIAL PROGRESSIVE POSITIVE TILT AND CONFLUENCE ACROSS THE LAKES WILL KEEP IT FROM MAKING IT TOO FAR NORTH BUT CANNOT RULE OUT NORTHERN FRINGE OF PCPN SHIELD CLIPPING OUR AREA. GUIDANCE OFTEN WEAKENS OR LOSES A STORM IN THE 4-5 DAY PERIOD ONLY TO LATCH BACK ONTO A STRONGER SOLUTION WITHIN 72 HOURS AS WAVE FINALLY REACHES OUR RADIOSONDE NETWORK. HAVE BEEN BURNT BY THIS SEVERAL TIMES SO OPTED TO RETAIN LOWER CHANCE POPS MAINLY MONDAY NIGHT...HIGHEST SOUTH. THIS WILL NEED TO BE MONITORED CLOSELY GIVEN PROSPECTS FOR A NARROW SWATH OF ACCUMULATING SNOW ON THE NORTHERN FLANK OF THIS SYSTEM. ATTENTION FOR THE MID TO LATE WEEK PERIOD WILL TURN TO TEMPERATURES AND CLOUD COVER. TOUGH FORECAST AS AREA LIKELY TO BE NEAR A FRONTAL BOUNDARY ON THE SOUTHWESTERN FRINGE OF A RETREATING POLAR JET...ESPECIALLY BY THURSDAY AND FRIDAY. A DEVELOPING NEGATIVE NAO/AO WILL HELP MAINTAIN NORTH ATLANTIC/EASTERN CANADA BLOCKING...WHILE -PNA AND NORTHEAST PACIFIC NEGATIVE HEIGHT ANOMALY ALLOW RIDGING/WARMTH TO OVERSPREAD THE PLAINS/MIDWEST. WE`LL BE IN BETWEEN MAKING IT A DIFFICULT FORECAST. GIVEN THE UNCERTAINTIES OPTED TO LOAD AND GO WITH THE 00Z ALLBLEND WHICH DOESN`T LOOK TOO BAD AT THIS POINT WITH TEMPS TRENDING UP TO NEAR NORMAL BY THURSDAY/FRIDAY. CLOUDS WITH ANY MOISTURE STARVED (LOW AMPLITUDE) SHORTWAVES IN WNW FLOW WILL ALSO IMPACT TEMPS...ESPECIALLY LATE THURSDAY INTO FRIDAY PER A ECMWF/GFS/GEFS COMPROMISE. GUIDANCE ALSO PRINTING OUT SOME LIGHT QPF WITH THIS WAVE BUT WILL HOLD OFF ADDING ANY POPS GIVEN TIMING DIFFERENCES AND LACK OF MOISTURE/FORCING WITH SHEARED WAVE(S). && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...T LONG TERM...STEINWEDEL AVIATION...AGD UPDATE...AGD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
548 PM EST SAT NOV 24 2012 .SYNOPSIS... SNOW CURRENTLY AFFECTING A LARGE PORTION OF THE FORECAST AREA WILL DIMINISH TONIGHT. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THE WEEK...WITH THE NEXT CHANCE FOR SNOW COMING MONDAY NIGHT INTO TUESDAY. && .NEAR TERM /THROUGH SUNDAY/... INVERSION HEIGHTS PER THE NAM AND RAP ARE ALREADY FALLING OFF THIS EVENING DOWNWIND OF LAKE ERIE. THEY STARTED OUT ABOVE 8 KFT EARLIER...AND SHOULD FALL TOWARD 5 KFT WITHIN THE NEXT FEW HOURS. WHILE INSTABILITY IS STILL RATHER IMPRESSIVE GIVEN LAKE TEMPERATURES AROUND +7 TO +8C AND MODEL 850 MB TEMPERATURES AROUND -11C...THE LENGTH OF FETCH OVER THE LAKE AS WELL AS UPSTREAM ANTECEDENT CONDITIONS REALLY ARE NOT. BOUNDARY LAYER DEWPOINTS NORTH OF LAKE HURON ARE RUNNING NEAR 10F...WHILE IS YIELDING DEWPOINT DEPRESSIONS OF 10-20F IN SOUTHERN ONTARIO. THIS IS JUST A BIT TOO DRY TO GET LAKE EFFECT HUMMING ALONG WITHOUT MULTI-LAKE FLOW CONDITIONS. AS IT STANDS...WE NEVER FULLY GOT A MULTI-LAKE CONNECTION BETWEEN LAKE HURON AND LAKE ERIE TO GET THE BANDING GOING OVER OUR AREA AS THE LOW LEVEL FLOW COMPONENT WAS A BIT TOO WESTERLY. AS A RESULT...WHILE WIDESPREAD SNOW SHOWERS DID STILL OCCUR...THE BANDING THAT FLOWED OVER MORE THAN ONE LAKE REMAINED MAINLY IN NORTHERN LOWER MICHIGAN (SUPERIOR/MICHIGAN) AND UPSTATE NEW YORK (HURON/ERIE). AS LOW LEVEL FLOW BACKS AGAIN TONIGHT IN RESPONSE TO ANOTHER SHORT WAVE DIVING SOUTHWARD...THIS SHOULD EVEN BRING THE SNOW SHOWERS AND FLURRIES WE HAVE AROUND THIS EVENING TO AN END. BECAUSE OF THE AFOREMENTIONED PROBLEMS FOR MODERATE SNOWFALL ACCUMULATIONS...THE LAKE EFFECT SNOW ADVISORY HAS BEEN DROPPED. ANY ENHANCED BANDS THAT MAY PERK UP THIS EVENING WILL BE HANDLED WITH SPECIAL WEATHER STATEMENTS...HOWEVER THE LIKELIHOOD OF STRONGER BANDS IS DECREASING BY THE HOUR ACROSS THE AREA. FRIES PREVIOUS DISCUSSION ABOUT TOMORROW FOLLOWS... A SHORTWAVE IS EXPECTED TO SPEED TO THE EAST TOMORROW...RACING FROM LOWER MICHIGAN IN THE MORNING TO NEW JERSEY IN THE EVENING. OVER THE LAST FEW DAYS...MODELS HAVE VERY GRADUALLY INTENSIFIED THE SHORTWAVE IN ADDITION TO BRINGING IT FARTHER TO THE SOUTH. APPEARS THAT ANY PRECIPITATION ASSOCIATED WITH THE SHORTWAVE WILL JUST GLANCE THE LOCAL FORECAST AREA...AND ALTHOUGH POPS COME A BIT FARTHER SOUTH THAN PREVIOUS FORECAST...HAVE NOT GONE MUCH FARTHER SOUTH THAN INTERSTATE 80. EXPECT SOME MINOR IMPROVEMENT IN HIGH TEMPERATURES COMPARED TO TODAY WITH SOUTHWESTERLY WINDS AT 10-15 MPH...BUT TEMPERATURES WILL STILL BE SEVERAL DEGREES BELOW NORMAL. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... WEAK HIGH PRESSURE WILL MOVE INTO THE SOUTHEASTERN UNITED STATES...ALLOWING FOR AT LEAST ONE DAY OF DRY WEATHER FOR ALL COUNTIES SUNDAY NIGHT INTO MONDAY. MODELS THEN FOLLOW THE HIGH PRESSURE WITH A CYCLONE...WITH MUCH OF THE PRECIPITATION FALLING TO THE NORTH OF THE SURFACE LOW. MODELS HAVE BEEN QUITE INCONSISTENT WITH THE STORM DURING THE LAST COUPLE OF DAYS...AND THEREFORE HAVE DECIDED NOT TO MAKE ANY MAJOR CHANGES TO THIS PORTION OF THE FORECAST. MADE SOME SLIGHT TWEAKS WITH TIMING OF SYSTEM...BUT OTHERWISE WILL KEEP GENERAL FORECAST OF CHANCE POPS...WITH SOME LIKELY POPS CREEPING INTO THE RIDGES. ANY PRECIPITATION IS EXPECTED TO START AS SNOW MONDAY NIGHT...WITH MOST PLACES CHANGING OVER TO RAIN ON TUESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A CHANCE OF A RAIN SNOW MIX OVER MOST OF THE REGION TUESDAY NIGHT INTO WEDNESDAY AS SURFACE LOW MOVES TOWARD THE UPPER OHIO VALLEY. THIS SYSTEM THEN MOVES EASTWARD BY WEDNESDAY WITH ANOTHER SHOT OF NORTHWEST FLOW AGAIN BRINGING THE CHANCE FOR A SHORT PERIOD OF LAKE EFFECT SNOW FLURRIES AND SHOWERS. THEN BY WEDNESDAY NIGHT DRY AND CONTINUED SEASONABLE THROUGH SATURDAY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... MVFR CONDS EXPECTED THRU EARLY TONIGHT...WITH LAKE EFFECT SNOW SHOWERS OCCURRING AT MOST TERMINALS EXCEPT ZZV. IMPROVEMENT TO VFR CONDITIONS OVERNIGHT. WINDS WILL TURN MORE WEST AS SURFACE RIDGE SHIFTS EAST OVERNIGHT. .OUTLOOK.../SUNDAY THROUGH THURSDAY/... A CLIPPER MOVING THROUGH THE REGION AHEAD OF NEXT SYSTEM WILL BRING CLOUDS FROM OVERRUNNING SUNDAY. CHANCE FOR MVFR/IFR WITH RAIN/SNOW LATE MONDAY INTO TUESDAY...LINGERING IN THE NORTHERN AREAS WEDNESDAY. CONDITIONS SHOULD DRY OUT BY THURSDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 PM EST SAT NOV 24 2012 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 350 PM EST SAT NOV 24 2012 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE GRT LKS BTWN TROF OVER ERN NAMERICA AND A RDG OVER THE ROCKIES. RIGHT NOW...THERE IS A SHRTWV RDG ALF DOMINATING THE UPR LKS...WITH SFC HI PRES RDG AXIS STRETCHING FM NOW ONTARIO S INTO THE UPPER MIDWEST. DESPITE THE APRCH OF THIS RDG AXIS AND LO INVRN BASE SHOWN ON THE 12Z INL/MPX RAOBS THAT HAS ALLOWED AT LEAST PARTIAL CLEARING OF LO CLDS OVER MN...THE SC OVER THE CWA HAS BEEN QUITE RESILIENT WITH H925-85 THERMAL TROF /H85 TEMPS IN THE -12C TO -15C RANGE/ UNDER HIER INVRNS H85-5 AS SHOWN ON THE 12Z GRB/APX RAOBS IN THE LLVL NW FLOW E OF THE INCOMING SFC HI PRES RDG. THESE LO CLDS ARE TENDING TO BREAK UP MORE AGGRESSIVELY OVER THE FAR SCENTRAL CWA WITH DOWNSLOPE NATURE OF THE LLVL FLOW. ALTHOUGH LOWERING SUBSIDENCE INVRN HAS TENDED TO CAUSE THE LES IN THE CHILLY NW FLOW TO DIMINISH WITH TIME...THE SHSN HAVE BEEN MOST PERSISTENT NEAR MUNISING WITH UPSTREAM MOISTENING OFF LK NIPIGON AND MORE LLVL CNVGC ENHANCING THE LES IN THAT AREA. LOOKING TO THE W...SKIES ARE PCLDY CLOSE TO THE SFC RDG AXIS...BUT THICKER CLDS ASSOCIATED WITH WAD IN THE SSW FLOW AHEAD OF ANOTHER SHRTWV NEAR LK WINNIPEG THAT HAS BEEN RIDING OVER THE ROCKIES RDG ARE MOVING STEADILY TO THE E INTO ERN MN THIS AFTN. SOME -SN HAS MOVED INTO NW MN THIS AFTN UNDER DEEP ISENTROPIC ASCENT/SOME UPR DVGC IN THE EXIT REGION OF 120KT H3 JET MAX SUPPORTING THE SHRTWV. MAIN FCST CONCERNS THRU SUN INCLUDE TIMING OF SN AND PCPN AMOUNTS TNGT IN ADVANCE OF CLIPPER TYPE SHRTWV NEAR LK WINNIPEG AND THEN TRANSITION TO LES ON SUN IN ITS WAKE. TNGT...AS SFC HI PRES RDG SHIFTS TO THE ERN GRT LKS...EXPECT SW FLOW/ISENTROPIC ASCENT BTWN DEPARTING RDG AND SHRTWV NEAR LK WINNIPEG TRACKING TO THE ESE ACRS ONTARIO TO DOMINATE. SINCE THE MAIN PV ANOMALY WL BE PASSING TO THE N...SHARPER ISENTROPIC ASCENT BEST SHOWN ON THE 280-290K SFCS /H8-65/ WL BE TRANSIENT AS WARM CONVEYOR BELT MSTR AXIS SWINGS THRU THE UPR LKS AHEAD OF DRY SLOTTING ON THE SRN FLANK OF PV ANOMALY TRACK. -SN SHOULD ARRIVE OVER THE W IN THE EVNG AND PUSH TO ERY AFTER 06Z...WHEN THE PCPN WL BEGIN TO DIMINISH W-E FOLLOWING THE SHIFT OF THE WARM CONVEYOR BELT RIBBON TO THE E. PCPN CHCS WL BE ENHANCED BY RIBBON OF H85-7 FGEN... SOME UPR DVGC IN LEFT EXIT REGION OF H3 JET MAX SUPPORTING THE ONTARIO SHRTWV...AND SOME DPVA ASSOCIATED WITH ANOTHER SHRTWV TRACKING THRU THE UPR MIDWEST ON THE SRN FLANK OF THE MAIN PV ANOMALY. GIVEN FCST H7 SPECIFIC HUMIDITY UP TO 2 G/KG AND A 3-6 HR PERIOD OF -SN WITH TRANSIENT WARM CONVEYOR BELT/DEEP ASCENT...LOOKS LIKE 1 TO 2 INCHES OF SN IS LIKELY WITH DECENT OMEGA IN THE DGZ. 12Z GUIDANCE SHOWS THE SHARPER ISENTROPIC ASCENT/FGEN IMPACTING THE WI BORDER AREA WITH HIER QPF/SN AMOUNTS ARND 2 INCHES MOST LIKELY THERE. SOME OF THE MODELS ALSO HINT THERE COULD BE SOME LK ENHANCEMENT OFF LK MI...BUT THE H925 WINDS LOOK TO BACK TO A MORE FAVORABLE SW DIRECTION ONLY BRIEFLY TO ALLOW FOR TOO MUCH ENHANCEMENT AT ISQ-ERY. WITH RELATIVELY QUICK ARRIVAL OF THICKER CLDS/WAD THIS EVNG...EXPECT NEAR STEADY TEMPS MUCH OF THE NGT AFTER EARLY MODEST DIURNAL TEMP FALL. SUN...LINGERING -SN OVER THE E WL END SOON AFTER 12Z FOLLOWING EXIT OF WARM CONVEYOR BELT MSTR RIBBON TO THE E AND ARRIVAL OF DRY SLOTTING. HOWEVER...12Z MODELS HAVE TENDED TO DIG THE PV ANOMALY MORE TO THE ESE OVER NE LK SUP DURING THE DAY. SO AS THE DAY GOES ON...A COLD CYC NW FLOW WL DVLP IN THE WAKE OF COLD FROPA AS ASSOCIATED SFC LO SHIFTS TO JUST E OF LK SUP BY 00Z MON. AT THE SAME TIME...AN AXIS OF SHARPER QVECTOR CNVGC/DPVA AND SOME DEEPER MSTR WL IMPACT MAINLY THE NE HALF OF THE FA CLOSER TO THE TRACK OF THE SHRTWV. WITH H85 TEMPS PROGGED TO FALL AS LO AS -15C OVER THE W HALF OF LK SUP IN THE AFTN...EXPECT MORE WDSPRD LES TO DEVELOP IN THAT AREA. ALSO BUMPED UP POPS OVER THE NE IN THE AFTN ESPECIALLY NEAR LK SUP GIVEN FAVORABLE ALIGNMENT OF ONSHORE WNW FLOW...DEEPER MSTR/ DPVA/QVECTOR CNVGC...AND COOLING. THE DAY SHOULD BE DRY OVER THE SCENTRAL WITH DOWNSLOPE FLOW IN THE ABSENCE OF ANY DYNAMIC SUPPORT/DEEP MSTR THERE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 350 PM EST SAT NOV 24 2012 THE MAIN FOCUS IN THE LONG TERM REVOLVES AROUND THE CHANCE FOR MODERATE LAKE EFFECT SNOW ACCUMULATION EAST NEAR LAKE SUPERIOR LATE SUNDAY NIGHT THROUGH MONDAY. EXACT LOCATIONS OF THIS POTENTIAL ARE STILL UNCERTAIN...THOUGH THE MAIN THREAT APPEARS TO BE IN ALGER COUNTY FROM MUNISING TO GRAND MARAIS AND SOUTH INTO NORTHERN SCHOOLCRAFT COUNTY. ANOTHER ROUND OF LIGHT SNOW VERY SIMILAR TO TONIGHTS SYSTEM WILL MOVE THROUGH THE AREA TUESDAY NIGHT. MILDER PATTERN CHANGES WILL THEN BE IN THE MAKING TOWARD THE END OF THE WEEK. SUNDAY NIGHT THROUGH MONDAY NIGHT...THE SHORTWAVE TROUGH ASSOCIATED WITH THE CLIPPER SYSTEM NOTED IN THE SHORT TERM WILL BE CROSSING NORTH-CENTRAL LAKE SUPERIOR AND WESTERN UPPER MI AT THE START OF THE PERIOD. THE ECMWF AND REGIONAL GEM HAVE BEEN QUICKER WITH THE SHORTWAVE WITH EACH PROGRESSIVE RUN...AND HAVE COME IN LINE WITH THE GFS AND NAM SOLUTIONS. TRENDS FROM BOTH THE GFS AND ECMWF ARE TO ADD SUBTLE AMPLIFICATION TO THE WNW FLOW IN THE MID-LEVELS OVER THE GREAT LAKES...WHILE THE REGIONAL GEM HAS TRENDED TO A LESS AMPLIFIED FLOW. PREFER THE IDEA PRESENTED BY THE GFS/ECMWF AS THE NICE SHOT OF CAA BEHIND THE LOW-LEVEL CLIPPER WILL LIKELY ADD SOME AMPLIFICATION TO THE MID-LEVEL TROUGHING. LINGERING LIGHT SNOW FROM THE CLIPPER WILL BE ENDING ACROSS THE EASTERN PORTION OF THE CWA AT 00Z MONDAY AS THE LOW DEPARTS INTO SE ONTARIO. CAA IMMEDIATELY BEHIND THE SYSTEM IS NOT ALL THAT IMPRESSIVE...WITH H8 TEMPS ONLY AROUND -10C OVER EASTERN LAKE SUPERIOR AT 06Z MONDAY. HOWEVER...H8 TEMPS BEGIN TO FALL FOR THE WESTERN HALF...REACHING -14C BY 06Z MONDAY. AT THE SAME TIME...A WEAK RIDGE BETWEEN THE DEPARTING TROUGH AND INCOMING AMPLIFYING TROUGH WILL BE PASSING OVERHEAD AND LIKELY DISRUPT THE LOW-LEVEL SURFACE FLOW. WHAT MAKES THIS CONCERNING IS THAT SFC TO H8 FLOW FROM THE NW WOULD PUT A DOMINANT LES BAND INTO FAR EASTERN ALGER COUNTY BEGINNING SUNDAY EVENING...WHILE A BACKING OF THE FLOW BEHIND THE SUBTLE RIDGE WOULD TEMPORARILY PUSH THE BAND ALONG THE SHORE. STILL BEING TWO DAYS OUT...THE CONNECTION BETWEEN THE MID-LEVEL FLOW AND SFC LES SET-UP IS SOMEWHAT UNCLEAR...BUT WOULD NOT BE SURPRISED IF THE BAND WOBBLES BETWEEN EASTERN ALGER COUNTY AND NORTHERN LUCE COUNTY ON EARLY MONDAY MORNING. THEN...THE SECONDARY TROUGH WILL AID LES INTENSITY ACROSS THE WHOLE NORTH SHORE OF UPPER MI LATER MONDAY MORNING INTO THE AFTERNOON. THIS WILL OCCUR AS THE BEST CAA AND COLDEST H8 TEMPS...AROUND -15 TO -16C...WILL BE MOVING OVER THE LAKE. ADDITIONALLY...LAKE-INDUCED EQUILIBRIUM VALUES BASED OFF OF A CONSERVATIVE LAKE WATER TEMPERATURE OF 5C WILL BE UPWARDS OF 7KFT ACROSS THE WEST AND 9KFT FOR THE EAST. FINALLY...THE DGZ WILL BE LOCATED IN THE HIGHEST 3KFT OF THE CONVECTIVE LAYER IN THE EAST...LEADING TO THE POTENTIAL FOR INCREASED AGGREGATION FROM DENDRITES AND THUS HIGHER SNOW RATIOS OF ABOUT 20 TO 1. THEREFORE...EXPECT THE HIGHEST LES INTENSITY MONDAY MORNING INTO EARLY AFTERNOON OVER THE EAST NEAR LAKE SUPERIOR. THE NAM...GEM...AND LOCAL WRF ALL HAVE A DOMINANT BAND WITH SIGNIFICANT LES FOR CENTRAL ALGER AND NORTHERN SCHOOLCRAFT COUNTY. A BLEND OF NAM AND LOCAL WRF QPF RESULTED IN ACCUMULATIONS OF 6-10 INCHES CENTERED OVER MELSTRAND. ONLY USED THIS BLEND TO SEE POTENTIAL AND WILL USE A MORE CONSERVATIVE APPROACH GIVEN THE UNCERTAINTY OF BAND PLACEMENT. NEEDLESS TO SAY...HEADLINES MAY BE NEEDED IF HI-RES MODELS REMAIN CONSISTENT WITH LES BAND PLACEMENT. DRY AIR ADVECTION FROM THE SOUTHWEST IN THE LOW LEVELS...AND H8 WAA OVERNIGHT MONDAY WILL BEGIN TO ERODE LES FROM WEST TO EAST ACROSS THE CWA. INVERSION HEIGHTS WILL ALSO CRASH FROM AROUND 9KFT 00Z TUESDAY TO <5KFT BY 09Z TUESDAY. MEANWHILE WINDS WILL BEGIN BACKING AND SHOULD PUSH REMAINING LES OFFSHORE...WITH LITTLE ACTIVITY REMAINING BY TUESDAY MORNING. TUESDAY THROUGH WEDNESDAY...ANOTHER SHORTWAVE TROUGH DIGGING ESE OUT OF CANADA WILL IMPACT THE CWA BY TUESDAY AFTERNOON AND BRING A ROUND OF LIGHT SNOW TO MAINLY THE NORTHERN CWA. THE BEST UPPER LEVEL PV ANOMALY AND MID-LEVEL Q-VECTOR DIVERGENCE ARE PROGGED TO MOVE THROUGH TUESDAY AFTERNOON AND EVENING. THE LEFT EXIT OF A 120KT NW TO SE ORIENTED UPPER JET WILL BE TRACKING ACROSS CENTRAL WI...SO BEST FEATURES DO NOT QUITE LINE UP. THE LOWEST LEVELS WILL BE DRY ENOUGH TO THE SOUTH TO PREVENT INITIAL PRECIP FROM REACHING THE GROUND. DID NOT MAKE MANY CHANGES TO THE PREVIOUS FORECAST OTHER THAN INCREASE POPS SLIGHTLY FOR THE ENTIRE CWA. THE TROUGH AXIS WILL THEN PASS THROUGH THE CWA BY 12Z WEDNESDAY AND USHER IN ANOTHER...YET SHORT-LIVED AND WEAKER...LES EVENT. INVERSION HEIGHTS COLLAPSE QUITE QUICKLY TO ABOUT 4KFT BY WEDNESDAY AFTERNOON...AND THE AIR BEHIND THIS SYSTEM IS CONSIDERABLY DRY THROUGHOUT THE COLUMN. THEREFORE...EXPECTATION IS THAT THERE WILL BE A QUICK LES EVENT WEDNESDAY MORNING INTO EARLY AFTERNOON FOR THE NW SNOWBELTS...MAINLY ACROSS THE KEWEENAW PENINSULA AND EAST OF MUNISING WHERE MOISTURE IS MORE ABUNDANT. WEDNESDAY NIGHT THROUGH SATURDAY...THE PATTERN TURNS QUIET FOR MUCH OF THE UPPER GREAT LAKES FOR THE SECOND HALF OF THE WEEK. OTHER THAN SOME LIGHT LES POSSIBLE EAST NEAR LAKE SUPERIOR ON THURSDAY NIGHT...NO REAL SIGNIFICANT PRECIP CHANCES PRESENT THEMSELVES AS THE MAIN ENERGY REMAINS SOUTH OF THE CWA WITH AN UPPER LEVEL DISTURBANCE MOVING ACROSS THE MID MISSISSIPPI VALLEY ON FRIDAY. THOUGH ON THE EDGE OF THE FORECAST PERIOD...A STRONG RIDGE WITHIN PACIFIC FLOW LOOKS TO BRING WELL-ABOVE AVERAGE TEMPS TO BEGIN DECEMBER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 350 PM EST SAT NOV 24 2012 EXPECT MVFR CIGS AT ALL 3 SITES TO GIVE WAY TO VFR CONDITIONS BY THIS EVNG WITH THE ARRIVAL OF A SFC HI PRES RDG AXIS. SOME -SN IN ADVANCE OF THE NEXT CLIPPER TYPE LO PRES SYSTEM WL THEN ARRIVE W-E LATER THIS EVNG...LIKELY DROPPING VSBYS TO IFR RANGE DURING THE EXPECTED 3-6HR PERIOD OF -SN. AFTER THE -SN ENDS W-E...EXPECT LINGERING MVFR CIGS WITH RESIDUAL LLVL MSTR. THE ARRIVAL OF COLDER AIR WL GENERATE MORE LK EFFECT -SHSN ON SUN MRNG...ESPECIALLY AT IWD AND ESPECIALLY CMX WHERE THE FCST W WIND WL UPSLOPE. ON THE OTHER HAND...CONDITIONS ARE LIKELY TO TREND TO VFR ON SUN AT SAW WITH DOWNSLOPE WIND COMPONENT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 350 PM EST SAT NOV 24 2012 EXPECT S-SW WINDS UP TO 20 KTS IN ADVANCE OF A CLIPPER SYSTEM TONIGHT TO VEER TO THE WNW ON SUN AS THE LO MOVES TO THE E OF LAKE SUP AND DRAGS A COLD FRONT ACROSS THE AREA. NORTHWEST WINDS OF 20 TO 30 KNOTS DUE TO HIGH PRESSURE QUICKLY IMPINGING ON A DEPARTING LOW OVER FAR EASTERN UPPER MICHIGAN WILL BE POSSIBLE SUNDAY NIGHT...WITH EVEN A FEW GALE FORCE GUSTS UP TO 35 KNOTS NOT OUT OF THE QUESTION. EXPECT THESE WINDS TO QUICKLY DECREASE ON MONDAY AS A HIGH PRESSURE RIDGE SETTLES OVER THE UPPER GREAT LAKES. SOUTHWEST WINDS OF 20 TO 25 KNOTS WILL THEN BE POSSIBLE...MAINLY FOR THE WEST HALF OF LAKE SUPERIOR ON TUESDAY AHEAD OF A COLD FRONT. ONCE THE FRONT PASSES TUESDAY AFTERNOON AND EVENING...WINDS WILL VEER TO THE W/NW AND INCREASE TO 20 TO 25 KNOTS FOR THE EAST HALF OF THE LAKE THROUGH WEDNESDAY. EXPECT WINDS TO REMAIN BELOW 20 KNOTS FOR THE REMAINDER OF THE PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KLUBER AVIATION...KC MARINE...KC/KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
309 PM CST SAT NOV 24 2012 .DISCUSSION... A SHORT WAVE AND CLIPPER LIKE LOW PRESSURE SYSTEM OVER EASTERN ND AT MID AFTERNOON WILL MOVE SOUTHEAST ACROSS THE MN/WI TONIGHT. THERE IS A DECENT PV ANOMALY AS WELL THAT WILL PASS BETWEEN THE TWIN CITIES AND DULUTH THIS EVENING. THIS SITUATION IS SOMEWHAT SIMILAR TO THAT OF THURSDAY EVENING...EXCEPT THE SYSTEM TONIGHT IS A LITTLE WEAKER AND THE ORIENTATION IS NW TO SE. PLENTY OF FORCING AND DEEP LAYER SATURATION IS SEEN BY THE VARIOUS MODEL SOLUTIONS PASSING ACROSS EAST CENTRAL MN AND WEST CENTRAL WI THIS EVENING. EVEN THE SOUTHERN EDGE OF THE THALER QG INSTANTANEOUS PRECIPITATION RATE NICKS THE TWIN CITIES THIS EVENING. HOWEVER...MUCH LIKE THURSDAYS SNOW EVENT...THE MODEL SOLUTIONS ARE VERY DRY FOR MUCH OF OUR CWA. THE EXCEPTION IS NEAR RUSK COUNTY WHERE A FEW HUNDREDTHS OF AN INCH ARE SEEN. THIS SEEMS UNREALISTIC WITH THE DEEP SATURATION SEEN COMBINED WITH THE OMEGA AND SNOW GROWTH ALMOST COLLOCATED. GRANTED IT ONLY LASTS FOR A FEW HOURS. RECENT RADAR TRENDS SHOWING SOME BANDING ACROSS EASTERN ND AND NW MN WITH MID LEVEL FRONTOGENESIS EVIDENT IN THE RAP JUST TO THE WEST. THEREFORE...USED LIKELY POPS THIS EVENING ALONG AND EAST OF A LINE FROM MILLE LACS TO EAU CLAIRE WITH AROUND AN INCH OF SNOW ACCUMULATION. CHANCE POPS FOR LITTLE FALLS..ST CLOUD...THE TWIN CITIES AND RED WING WITH ACCUMULATIONS LESS THAN AN INCH. KEPT CHANCE POPS IN PLACE OVER THE LADYSMITH AND AUGUSTA AREAS FOR THE OVERNIGHT HOURS. ANOTHER COLD DAY ON SUNDAY ALONG WITH BRISK NORTHWEST WINDS IN THE WAKE OF THE LOW AND COLD FRONT. HIGHS FROM THE LOWER 20S TO LOWER 30S FROM NORTH TO SOUTH. SKY COVER IS A LITTLE PROBLEMATIC ON SUNDAY. THE MORNING MAY BEGIN WITH SOME SUNSHINE BUT EXTENSIVE LOW CLOUDINESS MAY PUSH SOUTHWARD ACROSS THE FA DURING THE AFTERNOON AND NIGHT. CONFIDENCE IS NOT HIGH AND THIS COULD AFFECT THE OVERNIGHT LOW FOR SUNDAY NIGHT. AT THIS TIME...MONDAY SHOULD BE THE COLDEST DAY IN THE FORECAST PERIOD AS THE LOW LEVEL COLD TROUGH MOVES BY. HIGHS ARE ONLY FORECAST IN THE TEENS TO LOWER 20S. THE LONGER RANGE PORTION OF THE FORECAST THROUGH NEXT SATURDAY LOOKS DRY ALONG WITH A SLOW WARMING TREND. SOME PRECIPITATION IS LIKELY WELL NORTH OF OUR AREA ON TUESDAY AND PERHAPS AGAIN ON FRIDAY. BOTH THE EC AND GFS HAVE A LOW PRESSURE STORM SYSTEM DEVELOPING OVER THE CENTRAL AND NORTHERN PLAINS NEXT WEEKEND. THIS COULD BRING ANOTHER SURGE OF VERY MILD AIR INTO THE AREA FOR SUNDAY AND MONDAY. 850MB TEMPS ARE PROGGED INTO THE 8-12 DEG C RANGE. SOME EXTENDED GUIDANCE HIGHS ARE ALREADY NEAR 50 FOR THE TWIN CITIES NEXT SATURDAY. THE NORMAL HIGH IS 32. && .AVIATION... /18Z TAF ISSUANCE/ MAIN AVIATION CONCERN IS ONSET OF -SN THIS EVENING...AND HOW LOW THE VSBYS/CIGS COULD GET DEPENDING UPON THE STRENGTH OF THE SHRTWV MOVING ACROSS THE FA LATE THIS AFTN/EVENING. PREVIOUS TAFS HAD -SNSH FOR MOST AREAS EXCEPT RWF... WHICH SEEMS REASONABLE DUE TO UPSTREAM OBS AND THE STRENGTH OF THE SHRTWV. LATEST RAP HAS A FAIRLY STRONG WAA PATTERN DEVELOPING BY 21Z-00Z WHICH WOULD BE THE START OF SATURATION FROM THE TOP...DOWN. AFT 00Z...AS THE CONCENTRATION THE FAVORED DENDRITIC ZONE AND AMPLE LIFT DEVELOPS...COULD SEE VSBYS DROP TO 1-2SM IN THE NE FA IN SNOW. MAINLY AFFECTING RNH/EAU. ELSEWHERE...THE FAST NATURE OF THIS WAVE AND LIMITED TIME TO SATURATE THE LOWER LAYERS OF THE ATMOSPHERE...WILL ONLY HAVE -SN...WITH NO RESTRICTIONS TO VSBY. WINDS WILL START FROM THE SOUTH...BECOME MORE SW THIS EVENING...THEN SHIFT TO THE NW AND INCREASE OVERNIGHT...AND SUNDAY MORNING. A FEW GUSTS OVER 20 KTS ARE POSSIBLE BY 18Z. ANOTHER CONCERN IS WHETHER WE GET MVFR/IFR CIGS BEHIND THE FRONT LATE TONIGHT/SUNDAY MORNING. UPSTREAM OBS IN SOUTH CENTRAL CANADA HAVE BEEN IN THE IFR/MVFR RANGE THIS MORNING...AND THIS WOULD BE THE SOURCE REGION AS THIS AIR MASS MOVES SE OVERNIGHT. HAVE DECIDED TO ONLY INTRODUCE SCT012...BUT LATER SHIFTS WILL NEED TO UPDATE AS NECESSARY. KMSP... AS PREVIOUSLY STATED...FAST SHRTWV ACROSS SOUTH CENTRAL CANADA WILL PROVIDE INCREASING CLOUDINESS THIS AFTN/EVENING...WITH CLDS LOWERING TO LOW END VFR BY 00-03Z. HAVE KEPT VSBY UNRESTRICTED AS THE MAIN -SN SHOULD BE FURTHER TO THE E/NE OF MSP AIRFIELD...BUT LATER SHIFTS MAY CONSIDER LOWERING THESE VSBY TO MVFR IF THE SHRTWV IS STRONGER. WINDS WILL START FROM THE SSE...BECOME MORE SSW THIS EVENING...THEN SHIFT TO THE NW BY MORNING...WITH GUSTS LIKELY AFT 15-18Z. STILL NOT CONFIDENT ON MVFR CIGS BY SUNDAY AFTN...BUT SOMETHING TO CONSIDER DUE TO THE DEPTH OF THE MOISTURE BLW 3K IN THE LATEST MODEL RUN. /OUTLOOK FOR KMSP/ SUN/MON...MVFR CIGS POSSIBLE WITH -SNSH. WINDS WNW AT 10G20KTS. TUE...VFR. WINDS SSW AT 10 TO 15 KTS. WED...VFR. WINDS NE/E AT 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/JLT
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1138 AM CST SAT NOV 24 2012 .AVIATION.../18Z TAF ISSUANCE/ A RIDGE OF HIGH PRESSURE IS OFFERING A SHORT WINDOW OF VFR CONDITIONS ACROSS NE MINNESOTA AND NW WISCONSIN EARLY THIS AFTERNOON...EXCEPT AT KHYR WHERE THERE IS LINGERING MVFR CIGS. THE S WINDS WILL INCREASE THIS AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM. CLOUDS ARE EXPECTED TO INCREASE AND CIGS LOWER FROM WEST TO EAST THROUGH THIS AFTERNOON AND INTO THIS EVENING IN ADVANCE OF THE APPROACHING COLD FRONT ASSOCIATED WITH SYSTEM. THERE WILL BE PERIODS OF IFR/MVFR CONDITIONS THROUGH TONIGHT DUE TO CIGS AND REDUCED VIS FROM THE COMBINATION OF WIND AND -SN. THE WINDS WILL BECOME NW LATE THIS EVENING AND OVERNIGHT. THE -SN WILL DIMINISH OR MOVE OFF TO THE EAST LATE TONIGHT AND TOMORROW MORNING. THERE SHOULD BE LINGERING MVFR CIGS TOMORROW MORNING. && PREV DISCUSSION... /ISSUED 402 AM CST SAT NOV 24 2012/ SHORT TERM...TODAY THROUGH SUNDAY. AT 330 AM...A VARIETY OF CONDITIONS WERE FOUND ACROSS THE NORTHLAND. THERE WAS A LARGE AREA OF LOW CLOUDS ACROSS NW WI WITH SOME SNOW SHOWERS. A CHECK OF WEBCAMS IN THE HURLEY AREA INDICATED LITTLE SNOW ACTIVITY BUT LIKELY SOME SNOW SHOWERS OR FLURRIES. THERE WAS ANOTHER AREA OF LOW CLOUDS ACROSS WESTERN AREAS OF THE CWA WITH SOME SNOW SHOWERS AND FLURRIES AS WELL. CLEAR SKIES WERE FOUND IN A NW TO SE AREA IN BETWEEN. TEMPERATURES RANGED FROM THE TEENS IN CLOUDY AREAS TO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE CLEAR AREAS. A STRENGTHENING SHORTWAVE AND SURFACE LOW PRESSURE SYSTEM NOW MOVING INTO SASKATCHEWAN AND MONTANA WILL AFFECT THE WEATHER ACROSS THE REGION STARTING THIS AFTERNOON AND CONTINUING INTO SUNDAY. SKIES WILL BE PARTLY SUNNY FOR MOST AREAS THIS MORNING...BUT CLOUDS WILL QUICKLY INCREASE FROM THE WEST DURING THE DAY. A COMBINATION OF FAVORABLE JET DYNAMICS...Q-VECTOR CONVERGENCE AND FGEN WILL PRODUCE AN INCREASE IN SNOW STARTING THIS AFTERNOON AND CONTINUING INTO TONIGHT. THE HRRR AND 4KM WRF SEEM TO HAVE A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM. WILL INCREASE POPS CONSIDERABLY ACROSS THE BOARD...WITH CATEGORICAL POPS ACROSS THE NORTH AND LIKELY FOR MOST AREAS LATER TODAY AND THIS EVENING. CURRENT THINKING IS THAT THERE WILL BE WIDESPREAD 1 TO 3 INCH AMOUNTS...WITH 2 TO 4 INCHES ACROSS MUCH OF NORTHERN MN. COULD ALSO BE SOME HIGHER AMOUNTS ACROSS THE NORTH SHORE OF LAKE SUPERIOR...AS SOUTHWEST WINDS LEND SOME OROGRAPHIC LIFT ALONG THE NORTH SHORE. MAY NEED TO RAISE AMOUNTS THERE IN LATER FORECASTS. DRIER AIR WILL MOVE IN BEHIND THE SYSTEM TONIGHT AND INTO SUNDAY...WITH GUSTY WEST TO NORTHWEST WINDS BECOMING THE MAIN STORY FOR THE NORTHLAND ON SUNDAY. COULD STILL BE SOME LINGERING SNOW SHOWERS...ESPECIALLY ACROSS THE NORTH...AND LAKE EFFECT SNOW SHOWERS SHOULD DEVELOP FOR THE SOUTH SHORE. LONG TERM...SUNDAY NIGHT THROUGH SATURDAY. NW FLOW WILL BRING A CONTINUED CAA REGIME THROUGH THE WEEKEND. MODELS ARE IN GOOD AGREEMENT THAT H85 TEMPS FALL INTO THE NEGATIVE UPPER TEENS TO AROUND NEGATIVE 20 C EARLY MONDAY MORNING. HAVE LOWERED TEMPS SUNDAY NIGHT AND MONDAY TO ACCOUNT FOR THIS COLD AIR. THE NW TRAJECTORIES AND COLD H85 TEMPS WILL BRING AN OPPORTUNITY FOR LK EFFECT SNOW ALONG THE SOUTH SHORE OF LK SUPERIOR SUNDAY NIGHT INTO MONDAY WHERE LIGHT SNOW ACCUMULATION WILL BE POSSIBLE ALONG THE GOGEBIC RANGE. LATEST NAM BUFR SOUNDINGS SHOW THE STEEP LAPSE RATES ASSOCIATED WITH THE COLD AIR...AND A SHALLOW LAYER OF MOISTURE...REMAINS OVER THE ARROWHEAD ZONES THROUGH SUNDAY NIGHT WHERE FLURRIES OR VERY LIGHT SHSN MAY LINGER. LONG TERM MODELS CONTINUE TO SHOW ANOTHER SHORT WAVE DROPS OUT OF CANADA AND SWEEPS OVER THE NORTHLAND MID-WEEK. HAVE KEPT SMALL POPS IN THE NRN ZONES TUESDAY. && .POINT TEMPS/POPS... DLH 19 24 8 19 / 70 10 10 10 INL 15 19 6 17 / 70 10 10 10 BRD 19 25 6 17 / 30 10 10 0 HYR 20 28 10 20 / 60 10 10 0 ASX 22 30 15 22 / 70 10 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 AM CST SUNDAY FOR LSZ140. && $$ SHORT TERM...BERDES LONG TERM....GROCHOCINSKI AVIATION...GROCHOCINSKI
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1124 AM CST SAT NOV 24 2012 .DISCUSSION... OVERALL IT LOOKS TO BE A QUIET UPCOMING WEEK... ALTHOUGH THERE ARE A FEW ITEMS OF CONCERN. THE MAIN ISSUES PRESENT THEMSELVES OVER THE FIRST 36-48 HOURS OF THE FORECAST AS WE SEE ANOTHER CHANCE FOR SOME LIGHT SNOW ACROSS A PORTION OF THE AREA... FOLLOWED BY A REINFORCING BLAST OF COLD AIR. IN THE BIG PICTURE... THE RIDGE OUT WEST WILL REMAIN IN PLACE FOR THE EARLY PART OF THE WEEK AS UPPER ENERGY CURRENTLY CRESTING IT WORKS THROUGH OUR AREA AND HELPS MAINTAIN THE EASTERN TROUGH. HOWEVER... BY THE END OF THE WEEK THE ECMWF AND GFS BOTH SUGGEST THE PATTERN WILL BECOME MORE ZONAL AS A TROUGH STARTS TO SETUP OFF THE WEST COAST. INDICATIONS ARE THAT THIS WILL EVENTUALLY LEAD TO A DECENT RIDGE OVER THE CENTER/EASTERN PART OF THE COUNTRY TOWARD THE END OF NEXT WEEKEND INTO THE FOLLOWING WEEK... BUT FOR NOW WE NEED NOT WORRY ABOUT THAT AND WILL GENERALLY BE DEALING WITH BELOW NORMAL TEMPERATURES AND DRY WEATHER. INCREASING RETURN FLOW AND WARM ADVECTION TODAY WILL BRING INCREASING MID-HIGH CLOUDS THROUGH THE DAY. SHORTWAVE CURRENTLY WORKING THROUGH THE CANADIAN ROCKIES WILL DROP EAST-SOUTHEAST LATER TODAY AND THIS EVENING AND HELP DRIVE A SURFACE LOW BY TO OUR NORTH WHILE IT PUSHES A SURFACE TROUGH ACROSS OUR AREA. THE BEST UPPER LEVEL DIVERGENCE AND COMBINATION OF ISENTROPIC LIFT/SATURATION WILL STAY TO OUR NORTH... BUT WE SHOULD MANAGE TO SEE SOME SOUTHWARD EXTENSION OF PCPN ALONG/AHEAD OF THE TROUGH AXIS FROM LATE THIS AFTERNOON INTO TONIGHT. KEPT SOME CHANCE POPS GOING FOR THE NORTHERN PART OF THE CWFA... AND BRACKETED THEM WITH FLURRIES TO THE SOUTH. REMOVED THE MENTION OF FREEZING PCPN SINCE IT APPEARS THAT ANY ELEVATED WARM LAYER WILL STAY JUST SOUTH OF THE AREA OF PCPN. IF PCPN GETS FARTHER SOUTH THE FORECAST SOUNDINGS FROM THE NAM AND GFS WOULD SUGGEST THAT THE ELEVATED ABOVE 0C WARM LAYER SHOULD COOL TO THE WET BULB AND WOULD DROP BELOW FREEZING WITH ANY PCPN. OBVIOUSLY IF THE RETURN FLOW IS STRONG THAN EXPECTED AND THE WARM NOSE GETS FARTHER NORTH THEN THERE COULD BE AN ISSUE WITH SOME LIGHT FZRA OR SLEET ON THE SOUTHERN END OF THE PCPN AREA... BUT FOR NOW IT LOOKS LIKE WE SHOULD AVOID THAT SCENARIO. THE MAIN COLD FRONTAL BOUNDARY WILL DROP SOUTH THROUGH THE AREA SUNDAY AFTERNOON AND EVENING... WITH A BLAST OF COLD AIR ARRIVING FOR MONDAY. A FEW FLURRIES COULD BE SEEN IN THE WAKE OF THE FRONT... BUT FOR NOW IT LOOKS LIKE THOSE SHOULD STAY TO OUR NORTH/NORTHEAST AS ANTICYCLONIC BOUNDARY LAYER FLOW QUICKLY WORKS INTO OUR AREA. WINDS WILL STAY UP SOME THROUGH THE NIGHT SUNDAY NIGHT... WHICH WILL COMBINE WITH FALLING TEMPERATURES TO CREATE SOME BELOW ZERO WIND CHILLS ACROSS A GOOD PART OF THE AREA. MONDAY/S HIGHS WILL ONLY BE IN THE TEENS OVER THE NORTHWEST AND NORTH CENTRAL PORTION OF THE AREA... WITH MOST OTHER LOCATIONS BARELY ECLIPSING 20. IF CLOUD COVER STICKS AROUND MORE THAN EXPECTED THEN 20 COULD EVEN BE A STRETCH. THE REMAINDER OF THE WEEK WILL SEE PROGRESSIVELY WARMER TEMPERATURES... WITH READINGS NEAR OR PERHAPS A BIT ABOVE NORMAL BY THE END OF THE WEEK AS NORTHWEST UPPER FLOW BECOMES WESTERLY. THERE MAY EVENTUALLY BE A NEED TO INCLUDE SOME CHANCE OF PCPN FOR FRIDAY WITH BOTH THE ECMWF AND GFS SUGGESTING A SURFACE WAVE TO OUR SOUTH AND THE MAIN BAROCLINIC ZONE LOITERING NEARBY. HOWEVER... WITH VIRTUALLY NO RETURN FLOW INTO THE REGION THROUGH THE WEEK... IT IS TOO EARLY TO HAVE MUCH FAITH IN ANY PCPN BEING GENERATED AT THIS POINT. && .AVIATION.../18Z TAF ISSUANCE/ MAIN AVIATION CONCERN IS ONSET OF -SN THIS EVENING...AND HOW LOW THE VSBYS/CIGS COULD GET DEPENDING UPON THE STRENGTH OF THE SHRTWV MOVING ACROSS THE FA LATE THIS AFTN/EVENING. PREVIOUS TAFS HAD -SNSH FOR MOST AREAS EXCEPT RWF... WHICH SEEMS REASONABLE DUE TO UPSTREAM OBS AND THE STRENGTH OF THE SHRTWV. LATEST RAP HAS A FAIRLY STRONG WAA PATTERN DEVELOPING BY 21Z-00Z WHICH WOULD BE THE START OF SATURATION FROM THE TOP...DOWN. AFT 00Z...AS THE CONCENTRATION THE FAVORED DENDRITIC ZONE AND AMPLE LIFT DEVELOPS...COULD SEE VSBYS DROP TO 1-2SM IN THE NE FA IN SNOW. MAINLY AFFECTING RNH/EAU. ELSEWHERE...THE FAST NATURE OF THIS WAVE AND LIMITED TIME TO SATURATE THE LOWER LAYERS OF THE ATMOSPHERE...WILL ONLY HAVE -SN...WITH NO RESTRICTIONS TO VSBY. WINDS WILL START FROM THE SOUTH...BECOME MORE SW THIS EVENING...THEN SHIFT TO THE NW AND INCREASE OVERNIGHT...AND SUNDAY MORNING. A FEW GUSTS OVER 20 KTS ARE POSSIBLE BY 18Z. ANOTHER CONCERN IS WHETHER WE GET MVFR/IFR CIGS BEHIND THE FRONT LATE TONIGHT/SUNDAY MORNING. UPSTREAM OBS IN SOUTH CENTRAL CANADA HAVE BEEN IN THE IFR/MVFR RANGE THIS MORNING...AND THIS WOULD BE THE SOURCE REGION AS THIS AIR MASS MOVES SE OVERNIGHT. HAVE DECIDED TO ONLY INTRODUCE SCT012...BUT LATER SHIFTS WILL NEED TO UPDATE AS NECESSARY. KMSP... AS PREVIOUSLY STATED...FAST SHRTWV ACROSS SOUTH CENTRAL CANADA WILL PROVIDE INCREASING CLOUDINESS THIS AFTN/EVENING...WITH CLDS LOWERING TO LOW END VFR BY 00-03Z. HAVE KEPT VSBY UNRESTRICTED AS THE MAIN -SN SHOULD BE FURTHER TO THE E/NE OF MSP AIRFIELD...BUT LATER SHIFTS MAY CONSIDER LOWERING THESE VSBY TO MVFR IF THE SHRTWV IS STRONGER. WINDS WILL START FROM THE SSE...BECOME MORE SSW THIS EVENING...THEN SHIFT TO THE NW BY MORNING...WITH GUSTS LIKELY AFT 15-18Z. STILL NOT CONFIDENT ON MVFR CIGS BY SUNDAY AFTN...BUT SOMETHING TO CONSIDER DUE TO THE DEPTH OF THE MOISTURE BLW 3K IN THE LATEST MODEL RUN. /OUTLOOK FOR KMSP/ SUN/MON...MVFR CIGS POSSIBLE WITH -SNSH. WINDS WNW AT 10G20KTS. TUE...VFR. WINDS SSW AT 10 TO 15 KTS. WED...VFR. WINDS NE/E AT 5 TO 10 KTS. ..JLT.. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ TRH/JLT