Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 271039 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 539 AM EST THU NOV 27 2014 .SYNOPSIS... HAPPY THANKSGIVING FROM THE NATIONAL WEATHER SERVICE IN STATE COLLEGE. A WEAK UPPER AIR DISTURBANCE WILL KEEP CLOUDS AND THE CHANCE OF A FEW LIGHT SNOW SHOWERS IN THE FORECAST TODAY AND FRIDAY. TEMPERATURES WILL BEGIN TO MODERATE THIS WEEKEND AS HIGH PRESSURE MOVES OFF THE SE COAST. && .NEAR TERM /THROUGH TONIGHT/... AS THE STORM PULLS AWAY OFF THE NEW ENGLAND COAST...WE WILL BE LEFT TO DEAL WITH THE UPPER TROF THAT IS LAGGING BACK THROUGH THE GR LAKES. THIS WILL KEEP PLENTY OF CLOUD COVER AND SCATTERED LIGHT SNOW SHOWERS IN THE FORECAST. WITH GENERALLY WEAK NORTHWESTERLY FLOW...THE PRECIP SHOULD FAVOR THE USUAL WESTERN AND NORTHERN HIGH TERRAIN...TENDING TO DRY OUT AS ACTIVITY DOWNSLOPES INTO CENTRAL AND SOUTHERN AREAS. HIGHS TODAY WILL RANGE FROM THE UPPER 20S OVER THE NORTH TO MID 30S OVER THE SOUTH...WHICH WILL AVERAGE AROUND 10 DEG BELOW NORMAL. BIGGEST QUESTION FOR LATER TODAY INTO THE OVERNIGHT WILL BE WHETHER A PERIOD OF MORE ORGANIZED LAKE EFFECT CAN GATHER ITSELF OVER NWRN AREAS. DEEP LAYER FLOW DOES LOOK FAVORABLE FOR A TIME TONIGHT...BUT RELATIVELY SHORT OVER-LAKE TRAJECTORIES SHOULD LIMIT SNOWFALL TO MAINLY SUB ADVISORY LEVELS. I USED A MOS BLEND FOR THE OVERNIGHT LOWS IN THE 20S. THESE WILL BE SEVERAL DEG BELOW NORMAL. && .SHORT TERM /FRIDAY/... INVERSION HEIGHTS ARE EXPECTED TO LOWER FRIDAY WHICH SHOULD PUT A DAMPER ON ANY OF THE BEST DEVELOPED LAKE EFFECT BANDS...BUT CLOUDS AND PERHAPS A FEW SNOW SHOWERS WILL REMAIN POSSIBLE OVER THE NORMAL WESTERN AND NORTHERN LOCATIONS. THE BEST CHANCES WILL BE IN THE MORNING...WITH BRIGHTENING SKIES LIKELY IN THE AFTERNOON. HIGHS WILL BE A FEW DEG COOLER THAN TODAY AS THE CORE OF THE POST FRONTAL COLD AIR SETTLES OVERHEAD. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... ANOMALOUSLY LOW HEIGHTS OVER THE EASTERN US EARLY IN THE PERIOD WILL FLATTEN OUT INTO A BROAD ZONAL FLOW DURING THE WEEKEND. THIS WILL PROMPT A WARM-UP AS THE CYCLONE TRACK SHIFTS TO OUR NORTH AND HIGH PRESSURE MOVES OFF TO OUR SOUTHEAST. THE COLD POST FRONTAL AIRMASS WILL BEGIN MODERATING BY SATURDAY...WITH READINGS REACHING THE MILD RANGE BY SUNDAY. MODELS WHICH WERE IN DECENT AGREEMENT ON THE APPROACH OF A FRONT FOR MONDAY...NOW HAVE DIFFERENCES IN DROPPING A WEAK COLD FRONT THROUGH THE AREA EARLY NEXT WEEK. THE GFS/GEFS ARE FASTER AND HAVE HIGH PRESSURE BUILDING IN FOR MONDAY...WHILE THE ECMWF SLOWS ITS FRONTAL PASSAGE DOWN BY AT LEAST 12 HOURS. GIVEN THE FLAT FAST FLOW...SUCH DIFFERENCES ARE NOT UNEXPECTED. WHILE THE FRONT WILL REPRESENT THE BEST CHANCE FOR ORGANIZED PRECIP AND THE PASSAGE TIME IS UNCERTAIN...ZONAL FLOW WILL MAKE FOR A LACK OF MOISTURE KEEPING QPF BE ON THE LIGHT SIDE. ONE AREA OF POSSIBLE CONCERN COULD BE THE EXPECTED DEVELOPMENT OF SOME LIGHT WARM ADVECTION PRECIP SATURDAY NIGHT INTO SUNDAY MORNING. TEMPS ALOFT WARM RAPIDLY...AND I KEPT FORECAST SURFACE MINS MAINLY ABOVE FREEZING. BUT IF WE END UP A FEW DEG COOLER...WE COULD SEE A PERIOD OF SOME LIGHT ICING UNTIL TEMPERATURES CAN RECOVER SUNDAY. THE EXPECTED WARM UP OVER THE WEEKEND INTO EARLY NEXT WEEK SHOULD GO A LONG WAY TOWARD ERASING THE SNOW THAT BLANKETED THE REGION YESTERDAY. && .AVIATION /12Z THURSDAY THROUGH MONDAY/...
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WEAK RIDGING AT THE SFC AND ALOFT /IN THE WAKE OF YESTERDAY/S SNOWSTORM/ WILL BE OVER THE REGION INTO THIS AFTERNOON AS A WELL- DEFINED UPPER DISTURBANCE PASSES HARMLESSLY TO THE SOUTH OF PENN AIRFIELDS TODAY. VFR WILL CONTINUE ACROSS THE REGION NEAR AND SE OF A LINE FROM KAOO TO KUNV AND KIPT...WHILE MVFR WILL BE THE RULE ACROSS MUCH OF THE ALLEGHENY MTNS OF NRN AND WRN PENN. KJST SHOULD STAY VLIFR- LIFR THROUGH 12-14Z WITH SOME LIGHT FREEZING DRIZZLE POSSIBLE... BEFORE GRADUALLY IMPROVING TO UPPER END IFR OR MVFR AFTER 15Z TODAY. AFTERWARD...EXPECT PLENTY OF STRATO CU /TOPPED BY A LAYER OR TWO OF ALTOCU AND CIRRUS/ AND RELATIVELY LIGHT NW WINDS THROUGH 18-21Z TODAY WITH JUST SOME ISOLATED TO SCATTERED SNOW SHOWERS ACROSS THE NW MTNS AND LAUREL HIGHLANDS /FROM KBFD TO KJST/. SOME LAKE EFFECT -SHSN ARE FCST TO DEVELOP LATE THIS AFTERNOON THROUGH TONIGHT OVER THE WRN 1/3 WHERE REDUCED CONDS ARE LKLY TO PERSIST. COINCIDING WITH THE SNOW SHOWERS...WILL BE AN INCREASE IN THE NW WINDS AND ASSOCIATED GUSTS. LATE DAY/NIGHT-TIME WINDS SHOULD GUST IN EXCESS OF 20KTS ACROSS THE MTNS OF WRN PENN...WHILE GUSTS ELSEWHERE WILL LIKELY BE IN THE MID TO UPPER TEENS - MAINLY THIS AFTERNOON AND EVENING. OUTLOOK... TONIGHT...IFR/MVFR WITH OCNL -SHSN WRN 1/3. VFR TO MVFR CIGS CNTRL/EAST. FRI...AM MVFR/-SHSN NW...OTHERWISE BCMG VFR. SAT-SUN...MAINLY VFR. ISOLD -SHRA PSBL. MON...COLD FROPA. MAINLY VFR. SCT -SHRA PSBL.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...LA CORTE SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...LAMBERT

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