Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 290559 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 159 AM EDT FRI MAY 29 2015 .SYNOPSIS... SUMMER-LIKE CONDITIONS WITH ABOVE NORMAL TEMPERATURES WILL COME TO AN END BY THE END OF THE MONTH AS A COLD FRONT MOVES ACROSS CENTRAL PENNSYLVANIA THIS WEEKEND. THE FRONTAL PASSAGE WILL LIKELY BE ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. THE FRONT IS EXPECTED TO STALL NEAR THE MASON DIXON LINE WHICH SHOULD FAVOR A COOLER WEATHER PATTERN TO START THE MONTH OF JUNE. && .NEAR TERM /UNTIL 7 AM THIS MORNING/... ALL RADAR RETURNS STAYING SOUTH OF THE MD BORDER. LOWER SUSQ SITES MAY SEE LIGHT FOG IN THE MORNING AS IT SHOULD BE MAINLY CLEAR - AT LEAST EARLY - WITH DEWPOINTS A BIT HIGHER THAN ELSEWHERE IN THE CWA. SFC WINDS MAY START TO VEER AROUND TO THE SE-S BY THE END OF THE NIGHT AND BE AROUND 10 MPH OVER THE HIGH TERRAIN OF THE LAURELS. WILL GO WITH NIL POPS. INTERESTING CREEPING LOWER-VFR CLOUDS JUST INTO SRN SOMERSET CO NOW. WILL INCREASE CLOUD/SKY COVER FOR OVERNIGHT USING CONCEPT OF UPSLOPE SE WINDS COMING FROM AREA WHICH HAD SOME SHOWERS EARLIER TODAY AND NAM RH PROFILE AS A GUIDE. MOST OF THE MOISTURE IS WELL-ALOFT THOUGH. WHILE THE MESO MDLS CONTINUE TO GENERATE SOME CONVECTION IN THE FAR SE...HAVE TO DISCOUNT IT BASED ON THE OVER- DONE COVERAGE FCSTS THEY HAD IN FOR THIS AFTN/EVENING OVER PA AND NO SFC INSTABILITY. S/B A COMFORTABLE NIGHT FOR ALMOST ALL THE AREA. && .SHORT TERM /7 AM THIS MORNING THROUGH 6 PM SATURDAY/... THE AFOREMENTIONED RETURN SOUTHERLY FLOW WILL DRAW THE HUMID/UNSTABLE AIR MASS BACK INTO THE AREA FRIDAY...SUPPORTING SCATTERED DIURNAL PM CONVECTION. LIGHT WINDS BENEATH UPPER LVL RIDGE SHOULD RESULT IN NORTHWARD-DRIFTING PULSE TYPE TSRA WITH LITTLE THREAT OF SVR WX. MDL SOUNDINGS SUPPORT MAX TEMPS IN THE L80S MOST PLACES...WITH THE GREATEST DEPARTURES FROM AVG ACROSS WARREN CO DUE TO DOWNSLOPING SSE FLOW. BEST CHC OF CONVECTION WILL BE TO THE WEST CLOSER TO THE RING OF FIRE...AND OVER ELEVATED HEAT SOURCES FRI AFTN. HIGHS WILL RANGE THROUGH THE LOWER TO MIDDLE 80S FROM NORTH TO SOUTH. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE AT THE SFC AND ALOFT WILL ALLOW FOR SUBSIDENCE ONCE DAYTIME HEATING DIMINISHES FRIDAY EVENING. THERE IS A SLIGHT CHANCE FOR TOPOGRAPHIC FORCING TO ALLOW FOR A SLIGHT CHANCE OF PRECIPITATION FRIDAY NIGHT INTO SATURDAY THROUGH THE CENTRAL AND NORTHWESTERN MOUNTAINS. THE REST OF FRI NIGHT SHOULD BE FAIR AND SUMMERLIKE WITH HIGH DWPTS ALLOWING TEMPS TO FALL ONLY INTO THE 60S. MED RANGE GUIDANCE SIGNALS A CONTINUATION OF SUMMERLIKE WX INTO SATURDAY...WITH 12Z GEFS SHOWING ANOMALOUS 500MB HGTS AND SFC PRES OFF THE E COAST. HOWEVER AS SATURDAY CONTINUES THE HIGH WILL BE SHIFTED EASTWARD AND A LARGE UPPER LEVEL TROUGH WILL MOVE A FAIRLY STRONG BOUNDARY THROUGH CENTRAL PA. THE MODELS VARY IN THE TIMING BUT THERE WILL BE A BETTER CHC OF SHRA/TSRA BY MID TO LATE SATURDAY WITH APPROACH OF A COLD FRONT. THE LARGER MODEL TIMING DIFFS HAVE BEEN RESOLVED WITH MODEL CONSENSUS NOW PUSHING COLD FRONT THRU SUN MORNING. IN WAKE OF THE FRONT...A COUPLE DAYS OF CLOUDY...COOL AND SHOWERY WX APPEARS ON TAP FOR CENTRAL PA WITH FRONT STALLING OUT SOUTH OF PA AND A LIKELIHOOD OF OVERRUNNING RAIN/SHOWERS. ANOMALOUS EASTERLY FLOW/PWATS INDICATED IN 12Z GEFS OVER CENTRAL PA BTWN SFC HIGH OVR NEW ENG AND FRONT TO THE SOUTH. IN ADDITION TO THE MOISTURE...CENTRAL PA WILL REMAIN IN FAVORABLE JET ENTRANCE REGION SUN-MON..PROVIDING THE LG SCALE FORCING TO SUPPORT PERIODS OF RAIN SUN-MON..12Z GEFS MEAN QPF BTWN SUN-MON RANGES FROM 0.5 TO 1 INCHES. THE MODELS HAVE SHIFTED THE TIMING OF THE MOISTURE POOL SHIFTING IT SOUTH OF THE MASON DIXON. THIS HOWEVER COMES IN CONJUNCTION WITH AN INFLUX OF COLDER AIR AS A SFC HIGH BUILDS OVER EASTERN CANADA. HAVE CONTINUED TO LOWERED THE MAX TEMPS THROUGH THE FIRST HALF OF NEXT WEEK AND LOWERED POPS ACCORDINGLY. IMPROVING CONDS APPEAR LIKELY THROUGH MOST OF THE WORK WEEK AS UPPER RIDGE CONTINUES TO BUILD AND EXPAND NORTHWARD INTO PA. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... EXPECT JUST SOME SCT CIRRUS FOR THE REST OF THE OVERNIGHT AS A STALLED OUT FRONTAL BOUNDARY LINGERS JUST TO THE SOUTH OF THE MASON DIXON LINE AT 06Z...AND AN AREA OF BELOW NORMAL /SUB 0.50/ PWAT AIR AND SFC HIGH PRESSURE RESIDES OVER SOUTHERN NEW YORK STATE. ALTHOUGH VFR IS EXPECTED TO CONTINUE AT MOST AIRFIELDS FOR MUCH OF TODAY...KLNS COULD SEE SOME MVFR FOG THIS MORNING SINCE THE CLOSE PROXIMITY OF THE STALLED OUT SFC BOUNDARY COULD BEGIN TO DRIFT NORTH AND TRANSPORT SOME HIGHER DEWPOINT AIR INTO THE OTHERWISE CLEAR AND COOL AIRMASS WITH LIGHT WIND. SOME SHOWERS ARE POSSIBLE OVER THE FAR WESTERN AREAS LATER ON FRIDAY...AS MUCH HIGHER PWAT AIR OF AROUND 1.5 INCHES STREAMS NE FROM THE OHIO VALLEY. THEREFORE...HAVE VCSH MENTIONED FOR KBFD AND KJST AROUND AND AFTER 19Z. OUTLOOK... SAT...PATCHY MVFR FOG/CIGS EARLY. SCT-NMRS AFTERNOON TSTMS W/COLD FROPA. SUN-TUE...VFR/MVFR CONDS WITH SCT SHOWERS/TSTMS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO SHORT TERM...DEVOIR/FITZGERALD LONG TERM...FITZGERALD/CERU AVIATION...LAMBERT/MARTIN

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