Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 270222 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1022 PM EDT TUE MAY 26 2015 .SYNOPSIS... HIGH PRESSURE AT THE SFC AND ALOFT WILL REMAIN ANCHORED JUST OFF THE EAST COAST THROUGH THE END OF THIS WEEK. A COLD FRONT WILL LIKELY PUSH ACROSS THE REGION SATURDAY NIGHT...THEN STALL JUST SOUTH OF THE STATE EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 1015 PM UPDATE... MESOSCALE CONVECTIVE COMPLEX IS MOVING INTO FAR EASTERN OHIO...BUT WEAKENING AS IT DOES SO. MOST OF THE VERY SPARSE CONVECTION THAT DID FORM THIS EVENING DIES VERY QUICKLY OVER CENTRAL PA. THE WARMER TEMPS ALOFT CLOSER TO THE UPPER RIDGE AND THE LOSS OF DAYTIME HEATING WILL MOST LIKELY WEAKEN THIS STUFF EVEN FURTHER. SOME/SLIGHT DEVELOPMENT IS SEEN AT THIS TIME ON THE SRN FLANK. IF THIS DIMINISHES AS WELL...LITTLE TO NO PRECIP WILL GET INTO THE CWA...OR CERTAINLY CROSS RTE 219 BEFORE DAYBREAK. WILL PAINT LOW POPS IN FOR THE WEST AND NIL FOR THE EAST. WHILE A VERY ISOLATED SHOWER MAY POP OVER THE CENTRAL MTNS OR SUSQ VALLEY...IT IS NOT WORTH POPS AT THIS POINT. A MUGGY AND WARM NIGHT IS IN STORE AND SOME FOG IS POSSIBLE IN THE MORNING. PREV... DEEP SOUTH-SOUTHWESTERLY FLOW ON THE WESTERN PERIPHERY OF THE DOMINANT COAST RIDGE WILL CONTINUE TO TRANSPORT GULF OF MEX MOISTURE NORTHWARD INTO CENTRAL PA. WATER VAPOR LOOP AND RAP 300-400 MB WIND PROGS INDICATE THAT A WELL-DEFINED...ALBEIT COMPACT SHORT WAVE WILL BE MOVING NE ACROSS LAKE ERIE LATE THIS AFTERNOON...WHILE AN ASSOCIATED 45-50 KT JETLET CROSSES NRN AND WRN PENN. ENHANCED MESOSCALE LIFT FROM THIS FEATURE WILL TEAM UP WITH THE GROWING CAPE VALUES /LOCALLY AS HIGH AS 1000-1500 J/KG/ ACROSS THE ALLEGHENY PLATEAU TO PRODUCE INCREASINGLY NUMEROUS SHOWERS...AND A FEW TSRA LATE THIS AFTERNOON AND EARLY THIS EVENING. BLEND OF THE LATEST NAM/SREF AND HRRR CONTINUE TO FAVOR THE NRN MTNS...AND PORTIONS OF THE LAUREL HIGHLANDS FOR THE GREATEST CHC OF SHOWERS/SCTD TSRA. FOR AREAS SOUTH AND EAST OF KCBE TO KSEG AND KAVP LINE...THE PERIOD THROUGH 21Z SHOULD REMAIN DRY. HOWEVER...DIFFERENTIAL HEATING AT THE SE EDGE OF THE MID LEVEL CLOUD SHIELD...AND A RIBBON OF HIGHEST 850 MB THETA-E AIR ADVECTING EAST INTO THE MIDDLE SUSQ VALLEY SHOULD HELP TO FOCUS AND ENHANCE ANOTHER AREA OF SHOWERS THERE LATE TODAY. SPC PAINTS THEIR MARGINAL RISK OF SVR TSRA ACRS ROUGHLY THE WRN HALF OF PENN THIS AFTERNOON AND EVENING. BASIN AVG RAINFALL WILL BE GENERALLY AROUND 0.10 OF AN INCH IN MOST PLACES THROUGH MIDNIGHT...WITH SOME SPOTTY 0.25-0.50 INCH AMOUNTS IN TSRA. TEMPS ARE NEARING THEIR HIGHS FOR THE DAY RANGING FROM THE MID- UPR 70S OVR THE ALLEGHENY PLATEAU...TO THE M80S ACROSS THE LOWER SUSQ VALLEY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... A POTENT SHORTWAVE LIFTING THRU THE GRT LKS WILL INTRODUCE A BETTER CHC OF SHRA/TSRA ON WEDNESDAY. MDL TIMING OF THIS FEATURE SUGGESTS SHOWERS COULD ARRIVE EARLY IN THE DAY ACROSS THE W COUNTIES...WITH A GREATER RISK OF PM TSRA ACROSS EASTERN PA. GEFS MEAN CAPES PEAK ARND 1200 J/KG ACROSS THE SE COUNTIES WED AFTN. HOWEVER...MID LVL WINDS AND ASSOCIATED DEEP-LYR SHEAR ARE NOT PARTICULARLY STRONG IN THE LATEST MDL DATA...SO THE SVR WX THREAT JUST MRGL...AND THAT`S WHAT SPC COVERS PRACTICALLY ALL OF THE CWA WITH IN THEIR DAY 2 CONVECTIVE OUTLOOK. MCLDY SKIES WILL HOLD TEMPS DOWN A BIT...BUT CONSALL STILL SUGGESTS HIGH TEMPS BTWN THE M70S- L80S...SEVERAL DEG ABV NORMAL FOR LATE MAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UPPER LEVEL TROUGH WILL DEEPEN AS IT PROPAGATES EASTWARD. EXPECT COLD FRONT TO MOVE THROUGH PA...WEDNESDAY NIGHT INTO THURSDAY MORNING. THIS WILL BRING NORTHWESTERLY FLOW AND COOLER AND DRIER AIR. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL BUILD OVER THE REGION THROUGH FRIDAY...REDUCING ANY PRECIPITATION CHANCES THROUGH THE LATTER HALF OF THE WEEK AS THE BULK OF MED RANGE GUIDANCE IMPLIES DRIER WX AS LOWER PWAT AIR MASS WORKS INTO CENTRAL PA. A COLD FRONT WILL LIKELY BRING AN END TO THE SUMMER-LIKE WARMTH/HUMIDITY NEXT WEEKEND. A FAIR AMT OF AGREEMENT AMONG MED RANGE GUIDANCE FOR RAINY WX SATURDAY NIGHT INTO SUNDAY ALONG AN INCOMING FRONTAL BOUNDARY. SCATTERED SHOWERS COULD FOLLOW SUNDAY/MONDAY AS WAVE OF LOW PRES RIDES EASTWARD ALONG STALLED FRONTAL BNDRY SOUTH OF PA. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... A SUMMER-TIME PATTERN WILL PERSIST THROUGH THE WEEK. RADAR QUIET ACROSS CENTRAL PA THIS EVE...AND THAT SHOULD CONTINUE FOR MOST INTO THE OVERNIGHT HOURS. EARLIER RAINS AT KIPT HAVE PRODUCED SOME EARLY IFR FOG...BUT AS FLOW IN LOWER LEVELS INCREASES THIS SHOULD TAPER BACK TO MVFR. ELSEWHERE...VFR SHOULD CONTINUE FOR THE BULK OF THE TIME THROUGH THIS EVENING...BEFORE AFOREMENTIONED INCREASING LOWER LEVEL MOIST FLOW BRINGS POTENTIAL FOR A SEVERAL HOUR PERIOD OF MVFR FOG/CIGS TO DEVELOP TOWARD SUNRISE. SREF MODEL GUIDANCE SUGGESTS /AND EVEN NAM MOS HINTS/ THAT THE LOWER CIGS MAY LINGER INTO MID/LATE MORNING FROM KIPT- KMDT BEFORE A RETURN TO VFR. AT KBFD...THE ARRIVAL OF LOWER CIGS LATER TONIGHT WILL BE ACCOMPANIED BY MENTION OF SCT SHOWERS AS THE LOW LEVEL JET CORE SLIDES THROUGH. BETTER CHANCES FOR SHOWERS/POSS TSTMS ACROSS CWA BETWEEN 12-18Z IN WESTERN HALF...AND AFTER 16Z IN THE EAST. OUTLOOK... WED...PATCHY A.M. MVFR FOG/BR. SCT P.M. SHOWERS/TSTMS. THU-FRI...PATCHY A.M. MVFR FOG/BR. ISOLD P.M. TSTMS. SAT...PATCHY A.M. MVFR FOG/BR. SCT-NMRS P.M TSTMS W/COLD FROPA. SUN...MVFR CIGS POSS NW. OTHERWISE MAINLY VFR IN SCT SHOWERS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...FITZGERALD/CERU AVIATION...LAMBERT/RXR

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