Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 010718 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 318 AM EDT SUN MAY 1 2016 .SYNOPSIS... A LARGE LOW PRESSURE AREA OVER THE CENTRAL U.S. WILL MOVE EAST OVER THE NEXT FEW DAYS. EXPECT A PROLONGED PERIOD OF UNSETTLED WEATHER THROUGH AT LEAST EARLY MONDAY WHEN THE LOW WILL REDEVELOP ALONG THE MID ATLANTIC COAST AND MOVE OFFSHORE. DAMP CONDITIONS WILL CONTINUE NEXT WEEK WITH SEVERAL CHANCES FOR RAIN. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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A LARGE SHIELD OF WARM ADVECTION GENERATED RAIN CONTINUES TO MARCH EAST ACROSS THE CWA. RELATIVELY SMALL AREAS OF MDT (TO BRIEFLY HEAVY RAIN) RAIN WERE NOTED WITH REFELCTTIVITIES IN THE 30-40 DBZ ON REGIONAL 88D MOSAIC LOOP. BY DAYBREAK...THE BULK OF THE STEADIEST/HEAVIEST RAIN WILL BE ACROSS THE SUSQ VALLEY AND POINTS EAST...WITH PERHAPS A SECONDARY BAND OF SHOWERS ACROSS THE NRN MTNS. ADDITIONAL RAINFALL OVER THE NEXT 6 HOURS WILL AVERAGE 3-4 TENTHS OF AN INCH BASED ON RADAR ESTIMATES AND A CONSENSUS MODEL BLEND. TEMPS WILL BE NEARLY STEADY BETWEEN 45-50F WITH A SE BREEZE OF 5-10 KTS.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM MONDAY/... THE WAVE GENERATING THE RAIN WILL BE GETTING TO THE EAST OF OUR LATITUDE LATER IN THE MORNING...BUT RAIN WILL CONTINUE FOR AT LEAST THE MORNING IN THE EASTERN HALF OF THE AREA. THE WARMER AIR WILL TRY TO WORK DOWN TO THE SFC DURING THE DAY/AFTN BUT RESIDUAL MOISTURE MAY KEEP LOTS OF LOW CLOUDS IN PLACE. RAINFALL BY NOON WILL BE INTO THE 0.5 TO 1 INCH RANGE. THE LOW WILL MOVE INTO OH AND NW PA TODAY...OCCLUDING IT/S COLD AND WARM FRONTS AS IT DOES SO. A SECOND WAVE OF DECENT LIFT WILL COINCIDE WITH THE TRIPLE POINT INCHING INTO CENTRAL PA SUNDAY EVENING. WE WILL LIKELY BE IN AN AREA OF NVA AND DRYING ALOFT. SO FOR A WHILE IN THE DAYTIME ON SUNDAY...WE SHOULD BE IN A LULL (ESPECIALLY ACROSS THE SOUTHERN TIER COUNTIES). HOWEVER...IF SOME BREAKS CAN DEVELOP AND SOME MEAGER FORCING PASSES OVERHEAD...WE MAY BE ABLE TO POP A FEW TALL SHRA/LOW-TOPPED TSRA. BUT THE HEIGHTS WILL NOT HAVE FALLEN MUCH BY THAT TIME...AND THE CLOUD COVER MAY BE STICKING TIGHT. THE WARM SECTOR DOES GET RATHER CLOSE...THOUGH. THE WARM FRONT WILL BE BARELY INTO OR WILL BE HALTING AT THE LAURELS/ALLEGHENIES. THUS...LLVL SHEAR COULD BE MAXIMIZED THERE. A FEW ROTATING STORMS ARE POSSIBLE WITH LOWERED BUT PROBABLY ELEVATED INSTABILITY IN THAT S/W REGION. DUE TO THE PRESENCE OF ELEVATED INSTABILITY AND POSSIBILITY OF MIXING ACROSS THE REST OF THE AREA...WILL KEEP CHC/SCT TS IN THE FCST FOR THE AFTN/EVENING. MAXES WILL BE VERY MUCH DEPENDENT UPON THE AMOUNT OF SUNSHINE WHICH CAN BREAK THROUGH. A WARM START TO THE DAY WILL HELP US BUT THE PERSISTENT CLOUDS - ESP IN THE E - WILL LIMIT THE RISE. WILL GO WITH MAXES ONLY 5-6F HIGHER THAN MORNING TEMPS IN THE EAST...BUT MORE LIKE 10 OR 12F RISE IN THE WEST. THE WARM AIR MAY PUSH INTO THE AREA A BIT MORE OVERNIGHT...SO TEMPS SHOULD NOT FALL PAST THE U40S AND M50S. && .LONG TERM /MONDAY THROUGH SATURDAY/... RAIN WILL COME TO AN END AROUND MIDDAY MONDAY AS MAIN WAVE LIFTS INTO NEW ENGLAND. 48-HOUR FORECAST RAINFALL TOTALS ENDING 00Z TUESDAY ARE AROUND 1.00 NORTH TO 1.25 INCHES SOUTH...WITH HIGHER AMOUNTS OVER THE WESTERN ALLEGHENIES AND SOUTHERN TIER COUNTIES WHERE MARGINAL INSTABILITY MAY ALLOW FOR CONVECTIVE ENHANCEMENT. THE FCST RAINFALL SHOULD HELP THE AREA RECOVER FROM /60-90+ DAY/ DEFICITS GENERALLY ON THE ORDER OF -2.00 TO -4.00 INCHES. THE LATEST DROUGHT MONITOR NOW HAS OVER HALF OF PENNSYLVANIA IN ABNORMALLY DRY /D0/ CONDITIONS WITH A SMALL AREA OF MODERATE DROUGHT /D1/ CONDITIONS FOCUSED OVER BEDFORD COUNTY. A PERIOD OF IMPROVING/DRY WEATHER IS LIKELY FROM MONDAY AFTERNOON THROUGH TUESDAY BEFORE THE PATTERN TURNS QUITE UNSETTLED INTO THE MIDDLE AND SECOND HALF OF NEXT WEEK. THE GLOBAL ENSEMBLE MEANS ALL SHOW AN AMPLIFIED/ANOMALOUS MEAN UPPER TROUGH DEVELOPING AND SETTLING IN OVER THE ERN CONUS...WITH THE ECMWF A BIT DEEPER AND HOLDING ENERGY A BIT FURTHER WEST WHILE THE GFS POSITIONS A BIT MORE TO THE EAST. INTERESTINGLY...THE 12Z RUNS BOTH HAVE A 544DM 500MB LOW OVER E PA NOW AT 00Z SUN...SO MAYBE A GLIMPSE OF INCREASING CERTAINTY WORKING INTO THE SOLUTIONS. AT THE SURFACE...ECMWF AGAIN MORE AGGRESSIVE WITH AREA OF LOW PRESSURE OVER MID ATLANTIC BACKING INTO PA ON THU WHILE GFS BRINGS A WEAKER LOW ALONG SAME PATH FRI INTO SAT /EC ALSO SHOWS THIS AS AS SECOND WAVE/. SO THOUGH PATTERN LOOKS QUITE UNSETTLED... CONFIDENCE/PREDICTABILITY IN THE RAINFALL TIMING AND COVERAGE PATTERN REMAINS ON THE LOWER SIDE. DID FOCUS HIGHEST POPS ON THE THU-FRI PERIOD WITH THE UPPER CLOSED LOW AND SURFACE LOW STACKING...WHICH WILL ALSO BE POTENTIAL FOR HEAVIEST RAIN THIS PERIOD. OTHERWISE IT LOOKS LIKE A CLOUDY AND WET WEEK WITH PERIODS OF GENERALLY LIGHT PRECIPITATION AND RELATIVELY COOL TEMPERATURES VS. SEASONAL CLIMATOLOGY. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/...
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LOW PRESSURE APPROACHING THE OHIO VALLEY OVERNIGHT HAS CAUSED WIDESPREAD RAIN SHOWERS ACROSS THE REGION AND WILL AFFECT ALL TAF SITES. MVFR TO IFR CONDITIONS EXPECTED AT ALL TAF SITES...WITH THEWORST PERIOD BEING 09Z TO 13Z. A WARM FRONT EXTENDING IN FROM THE MAIN LOW WILL TRY TO LIFT INTO THE CENTRAL MTNS...BUT WILL LIKELY STALL OVER SWRN/WRN PA. HOWEVER...SOME CLEARING IN THE DAYTIME COULD PRODUCE SCT SHRA/TSRA ACROSS ALL OF THE AREA. THE MAIN THREAT AREA FOR TSRA IS VCTY JST/AOO. A SECOND WIDE AREA OF RAIN/LOW CIGS/VIS WILL PUSH ACROSS AS THE MAIN SFC LOW PUSHES THROUGH SUN NIGHT/EARLY MONDAY MORNING. DRIER AIR WILL WORK IN FOR A VERY BRIEF TIME ON MONDAY. A WAVE RIDING THROUGH THE DEEP SOUTH AND MID-ATLANTIC STATES ON TUESDAY WILL PROBABLY SPREAD MORE RAIN INTO THE SE HALF OF THE AREA MON NIGHT/TUES. OUTLOOK... MON PM-TUE...RA POSS SE. TUE PM...NO SIG WX. WED...SHRA POSS. THU...IFR POSS IN RA/FG.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...DANGELO LONG TERM...RXR AVIATION...CERU/GARTNER

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