Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 202347 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 747 PM EDT MON OCT 20 2014 .SYNOPSIS... LOW PRESSURE MOVING ACROSS THE LOWER GREAT LAKES TONIGHT WILL FILL IN AS IT MOVES OVER THE STATE THEN RE-FORM JUST OFF THE COAST ON TUESDAY. THE LOW PRESSURE WILL LINGER OFF THE MID ATLANTIC COAST AND KEEP IT DAMP AND SHOWERY INTO WEDNESDAY. CONDITIONS WILL SLOWLY IMPROVE DURING THE LATTER PART OF THE WEEK...AS THE STORM SLOWLY MOVES AWAY FROM THE AREA. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... SFC LOW OVER LAKE HURON AND EVEN SOME THUNDER BACK UNDER THE UPPER TROUGH/LOW AND ALONG THE FRONT INTO NWRN OH AT 18Z. LOCALLY...STILL LOTS OF VIRGA ON THE RADAR BUT SO FAR NO OBS HAVE HELD ANY PRECIP. THE MOISTURE WILL CONTINUE TO GET DEEPER THIS EVENING AND SHOWERS SHOULD START BY 00Z IN THE FAR NW WITH A FEW SPRINKLES POSSIBLE IN THE SE AND A DRY SLOT IN BETWEEN PER THE LATEST RAP/NAM. SFC LOW FILLS/BROADENS AND THE COLD FRONT WASHES OUT BY 06Z AND BY 12Z...THE DOLDRUMS WILL BE OVER CENTRAL PA. WILL KEEP POPS GENERALLY LOW UNTIL AFTER MIDNIGHT OVER THE AREA...BUT IT WILL AT LEAST SPRINKLE OR DRIZZLE OVERNIGHT IN MOST PLACES NW OF STATE COLLEGE. WILL CONTINUE ON WITH CURRENT CATG POPS IN THE NWRN HALF AND CHCS IN THE SE HALF. TEMPS SHOULD STAY VERY MILD FOR THIS TIME OF YEAR UNDER THE CLOUDS AND INITIALLY SRLY WIND. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... THE LOWERED PRESSURES WILL SLIDE EASTWARD ON TUESDAY AND BY TUES NIGHT A DEEPER LOW WILL FORM NEAR ATLANTIC CITY. WILL NOT GAMBLE AND WILL GO WITH THE VERY HIGH PROBABILITY FORECAST WHICH BY NO CHANCE IS ALSO CONTINUITY. COOL BUT WET NRLY/WRLY FLOW AROUND THE LOW WILL CREATE VERY CLOUDY AND DAMP WX OVER THE SHORT RANGE PERIOD. THE UPPER LOW WILL BE OVERHEAD TUESDAY NIGHT AND THE FALLING HEIGHTS AND COOLER AIR ALOFT DURING THE DAY TUESDAY COULD ALLOW FOR SOME INSTABILITY TO DEVELOP WITH THE SMALLEST OF BREAKS IN THE CLOUDS. WILL LEAVE THUNDER OUT FOR NOW...AND PLAY THE COOL AND STABLE CARD. DIURNAL RANGE TUES WILL BE JUST 8-12F IN MOST PLACES...AND KEEP MAXES BELOW NORMALS. 8H TEMPS GENERALLY STAY ABOVE ZERO. BUT LATE TUES NIGHT/WED AM MAY BE COLD ENOUGH OVER THE LAURELS TO HAVE SOME SNOW MIX IN WITH ANY RAIN SHOWERS ON THE HIGHEST ELEVS. HAVE CHOSEN TO LEAVE OUT MENTIONS OF ANY MIX AT THIS POINT. THE CORE OF THE COLD AIR COULD GO TO OUR SOUTH WITH HELP FROM THE CIRCULATION OF THE UPPER LOW...WHICH KEEPS THAT MARITIME AIR WRAPPING IN TO THE AREA. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AN UNUSUALLY HIGH DEGREE OF MODEL/ENSEMBLE AGREEMENT IS LEADING TO A HIGH CONFIDENCE FORECAST FOR MUCH OF THE LONG TERM PERIOD. THE OVERWHELMINGLY DOMINANT MAIN FEATURE TO AFFECT THE LOCAL AREA DURING THIS PERIOD WILL BE A CUT-OFF...SLOW-MOVING UPPER LOW...PROGGED TO GRADUALLY DEEPEN AS IT DRIFTS OVERHEAD AND REACHES THE EAST COAST /TO AROUND 550DM/ THEN PICK UP SOME SPEED AS IT LIFTS TO THE NORTHEAST THROUGH THE FIRST HALF OF THE LONG TERM PERIOD. THE POSITION OF THE STORM WILL KEEP LOTS OF MARITIME AIR FLOWING IN FROM THE NORTH/EAST AND KEEP POPS PRETTY HIGH ON WED...BUT SOME IMPROVEMENT IS POSSIBLE ON THURSDAY. THE HIGHEST POPS WILL GENERALLY BE IN THE NRN HALF - ESP THE NE. BUT THE MOISTURE WILL WRAP AROUND THE STORM COMPLETELY AT TIMES. THUS...A MOIST UPSLOPE FLOW IN THE WRN MTNS WILL KEEP PLENTY OF CLOUDS IN PLACE WITH SHOWER CHCS HIGH THERE AS WELL DURING MID-WEEK. AS A SURFACE LOW DEVELOPS UNDER THE UPPER SYSTEM OFF THE NJ/NY COAST...NORTHERLY LOW LEVEL FLOW WILL INCREASE AND BRING A PERIOD OF BREEZY CONDITIONS WED INTO THU...AND POSS EVEN INTO FRI. EVENTUALLY...SFC HIGH PRESSURE AND CONCURRENT UPPER RIDGING SHOULD LEAD TO A DRY WEEKEND WITH WESTERLY FLOW AND MILDER TEMPERATURES ON SAT. THERE COULD BE A WEAK AND DRY FRONT DROP ACROSS THE GREAT LAKES AND MID-ATLANTIC ON SUNDAY...WHICH MAY PRODUCE WIDELY SCT SHOWERS...BUT IT IS NOT WORTH A POP AT THIS POINT. TEMPS MAY THEN DIP A FEW DEGS FROM SAT-SUN. OTHERWISE... GENERALLY ZONAL FLOW LOOKS TO BE THE RULE AT THE LONGEST OF RANGES IN THE LOCAL FORECAST WITH CHANCE FOR JUST WEAK WAVES TO IMPACT CENTRAL PA. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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LOW PRESSURE APPROACHING FROM THE GRT LKS WILL BRING DETERIORATING FLYING CONDS TO CENTRAL PA TONIGHT IN THE FORM OF LOWERING CIGS AND SHOWERS. AS OF 23Z...WIDESPREAD VFR CONDS REPORTED. HOWEVER...A PERIOD OF STEADY RAIN IS LIKELY TO MOVE INTO THE NW MTNS THIS EVENING AND SCT SHOWERS ARE LIKELY ELSEWHERE OVERNIGHT. MAIN CONCERN OVERNIGHT WILL BE DEVELOPING LOW CIGS AT KBFD. MDLS SUGGEST AN INCREASINGLY MOIST SOUTHERLY FLOW ASCENDING THE NW MTNS WILL CAUSE CIGS TO FALL INTO THE IFR RANGE AT KBFD LATE TONIGHT. ELSEWHERE...NO WORSE THAN MVFR CONDS EXPECTED OVERNIGHT. AS COLD FRONT PUSHES THRU TUE AM...WIND WILL SHIFT FROM SOUTHERLY TO NWRLY. THE RESULTING UPSLOPE FLOW OVR THE LAUREL HIGHLANDS WILL PLACE KJST AT RISK FOR IFR CIGS BTWN 11Z-15Z. EXPECT RISING CIGS EVERYWHERE BY AFTN...AS MODEST DIURNAL WARMING OCCURS WITHIN THE SFC TO 1KM LAYER. BY AFTN...MDL SOUNDINGS AND MOS GUIDANCE SUPPORT MVFR CIGS AT KBFD/KJST...WITH PREDOMINATELY VFR CONDS FURTHER EAST. HOWEVER...COOL TEMPS ALOFT WILL CREATE AN UNSTABLE ENVIRONMENT THAT WILL LEAD TO NUMEROUS PM SHRA AND EVEN A POSS TSRA. ANY OF THESE SHRA/TSRA COULD PRODUCE A BRIEF DIP TO IFR VSBY. SCT SHOWERS OF DIMINISHING INTENSITY WILL CONTINUE TO AFFECT THE REGION TUE NIGHT...AS SLOW MOVING LOW PRES SYSTEM MOVES THRU THE AREA. HOWEVER...BIGGEST AVIATION CONCERN WILL BE THE POTENTIAL OF LOW CIGS REDEVELOPING TUE NIGHT AT KBFD/KJST...THE RESULT OF RADIATIONAL COOLING OF THE SFC-1KM LAYER AND UPSLOPE FLOW. DOWNSLOPING NW FLOW SHOULD YIELD MUCH MORE FAVORABLE CONDS FURTHER EAST. OUTLOOK... WED-FRI...LOW CIGS POSS W MTNS...MAINLY AT NIGHT/EARLY AM. SAT...NO SIG WX EXPECTED.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...RXR AVIATION...FITZGERALD

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