Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280733 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 233 AM EST FRI NOV 28 2014 .SYNOPSIS... A WEAK UPPER AIR DISTURBANCE WILL KEEP CLOUDS AND THE CHANCE OF A FEW LIGHT SNOW SHOWERS IN THE FORECAST TONIGHT AND FRIDAY. TEMPERATURES WILL BEGIN TO MODERATE THIS WEEKEND AS HIGH PRESSURE MOVES OFF THE SE COAST. THE NEXT DISTURBANCE WILL BRING LIGHT RAIN SHOWERS EARLY NEXT WEEK BEFORE A QUICK SHOT OF COOLER AIR FOR MIDWEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... DID UP POPS AND SNOW AMTS SOME FOR MCKEAN...CAMBRIA...AND SOMERSET COUNTIES. HAD CHC POPS...WENT UP TO LIKELY IN SOME SPOTS...WITH A FEW INCHES. FIRST CONCERN IS CLUSTERS OF SNOW SHOWERS...WHICH ARE LARGELY CONVECTIVE...GIVEN COLD AIR ALOFT. NO REAL FOCUS...MORE CONCERN ABOUT RATE OF FALL...THAN AMTS...SEE HWO. SECOND CONCERN IS LAKE RESPONSE. AS WIND FIELDS BECOME MORE W TO NW...INPUT FROM THE UPPER LAKES MAY BE MORE OF A FACTOR LATE TONIGHT. STARTING TO SEE RADAR RETURNS AT RATHER FAR DISTANCE FOR SNOW...JUST SW OF BUF. AT THIS POINT STILL DO NOT EXPECT SIGNIFICANT SNOW ACCUMS WITH BOTH THESE...BUT THERE COULD BE ENOUGH TO COAT ROADS AND CAUSE SOME SLICK SPOTS...SO HAVE UPDATED PHLHWOCTP TO GIVE THE PUBLIC/CUSTOMERS A HEADS UP. WILL CONTINUE TO MONITOR THE SITUATION AND UPDATE AS NEEDED. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... 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 /SATURDAY NIGHT THROUGH THURSDAY/... BROAD ZONAL FLOW DEVELOPS DURING THE WEEKEND. THIS WILL PROMPT A WARM-UP AS LOW LEVEL FLOW VEERS TO THE SW AS HIGH PRESSURE SLIPS OFF FURTHER TO OUR SOUTHEAST. AFTER A CHILLY NIGHT FRI NIGHT WITH LOWS INVOF 20F...THE AIRMASS WILL BEGIN MODERATING ON SATURDAY...WITH READINGS REACHING THE MID 40S TO MID 50S BY SUNDAY. MAY SEE SCT LIGHT SHSN ACROSS NW MTNS IN WEAK NW/W FLOW. MODELS SEEM TO BE BACK IN BETTER AGREEMENT ON APPROACH OF A FRONT FOR MONDAY...THOUGH GFS/GEFS CONTINUE TO BE 6 TO MAYBE 12 HRS FASTER WITH FROPA. AHEAD OF THAT...ONE AREA OF POSSIBLE CONCERN COULD BE THE EXPECTED DEVELOPMENT OF SOME LIGHT WARM ADVECTION PRECIP SATURDAY NIGHT INTO SUNDAY MORNING MAINLY ACROSS WESTERN SECTIONS. 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. POST FRONT WILL BRING COOLER TEMPS BACK IN FOR MIDWEEK AS LARGE SURFACE HIGH SLIDES ACROSS S CANADA...BUT NOTABLE MODEL DIFFS BEGIN TO DEVELOP AROUND THEN WITH ECMWF MUCH FLATTER THAN GFS. EC SOLUTION BRINGS HIGH PRESSURE OVER THE REGION BY LATE WEEK WITH SLOWLY MODERATING TEMPS...WHILE THE GFS/GEFS SPINS UP A SURFACE LOW OVER THE MIDWEST WHICH WOULD PUSH EVEN WARMER TEMPS OUR WAY. FOR NOW...TEMPERED WARMUP A BIT AS MUCH UNCERTAINTY IN LATER TIME PERIODS. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... THE MAIN AVIATION CONCERN THIS PERIOD WILL BE THE LIKELIHOOD OF LOW CIGS/SHSN AT KJST BTWN 06Z-09Z...CAUSED BY THE PASSAGE OF AN UPPER LVL TROUGH. CIGS AT KJST HAVE BEEN RUNNING ARND 800 FT EARLY THIS AM...AND RADAR TRENDS SUGGESTS A HEAVIER SHSN WILL LIKELY DROP THE VIS BLW 1SM BTWN 08Z-09Z...WITH A BRIEF DIP BLW 3SM LIKELY AT KAOO BTWN 08Z-09Z. ELSEWHERE...LAKE EFFECT SNOW SHOWERS SHOULD PRODUCE PRIMARILY MVFR CONDS AT KBFD EARLY THIS AM...WHILE DOWNSLOPING FLOW SHOULD RESULT IN A HIGH CONFIDENCE OF VFR CONDS AT KMDT/KLNS. A RIDGE OF HIGH PRES BUILDING IN FROM THE OHIO VALLEY SHOULD CAUSE ANY LINGERING -SHSN OVR THE W MTNS TO DISSIPATE BY LATE AM...WITH WIDESPREAD VFR CONDS LIKELY BY THIS AFTN. A WARM FRONT LIFTING INTO THE REGION COULD PRODUCE A PERIOD OF LGT SNOW/REDUCED VSBYS LATE TONIGHT OR EARLY SAT AM. OUTLOOK... SAT...AM LGT SNOW/REDUCED VSBYS POSS...MAINLY NORTH. LOW CIGS AT KBFD POSS SAT NIGHT. SUN...AM LOW CIGS/DZ POSS KBFD. MON...LOW CIGS/SHRA POSS...MAINLY W MTNS. TUE...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/GARTNER NEAR TERM...GARTNER/MARTIN SHORT TERM...LA CORTE LONG TERM...RXR AVIATION...FITZGERALD

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