Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 261143 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 743 AM EDT TUE APR 26 2016 .SYNOPSIS... LOW PRESSURE OVER SOUTHERN MICHIGAN WILL MOVE EAST AND TRACK OVER NRN PA/WRN NY STATE TODAY. THIS LOW WILL PUSH A COLD FRONT THROUGH THE AREA TODAY. A LARGE AREA OF HIGH PRESSURE OVER SOUTH CENTRAL CANADA WILL RIDGE SOUTHEAST ACROSS THE GREAT LAKES AND INTO PENNSYLVANIA WEDNESDAY INTO THURSDAY WITH FAIR AND COOLER CONDITIONS. ANOTHER AREA OF LOW PRESSURE TRACK SOUTH OF PENNSYLVANIA THURSDAY INTO FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SUBSTANTIALLY WEAKENED MCS HEADED ACROSS THE ALLEGHENY PLATEAU OF NRN AND WRN PENN AT 1030Z. THIS FEATURE WILL SPREAD SHOWERS AND A FEW BRIEF...LOW-TOPPED TSRA ACROSS THE CENTRAL MTNS AND SUSQ VALLEY DURING THE MID TO LATE MORNING HOURS TODAY. SFC COLD FRONT EXTENDING FROM LOW PRESSURE NEAR DETROIT WILL BE LAGGING THIS MCS BY SEVERAL HOURS. DEWPOINTS WILL RECOVER INTO THE MID AND UPPER 50S ACROSS SOUTHERN PENN THIS AFTERNOON...AND THEY WILL COMBINE WITH PARTLY SUNNY SKIES AND MDTLY STRONG DEEP LAYER WESTERLY SHEAR TO PRODUCE A RISK OF STRONG TO SEVERE TSRA DURING THE EARLY TO MID AFTERNOON HOURS OVER THE SERN HALF OF THE STATE. THE SFC FRONTAL WAVE TRACKS ALONG THE PA/NY BORDER THIS AFTERNOON...WITH ITS SOUTHWESTWARD TRAILING COLD FRONT SETTLING ACROSS THE COMMONWEALTH LATE THIS AFTERNOON AND THIS EVENING. A SECOND ROUND OF CONVECTION SHOULD REFIRE DURING THE LATE MORNING AND EARLY AFTERNOON HOURS ACROSS CENTRAL AND WESTERN PENN...THEN STEADILY EXPAND TO THE ESE ACROSS THE LOWER/MID SUSQ VALLEY AND SOUTHERN TIER OF PENN AS THE MILDER AND MORE UNSTABLE AIR PUSHES NORTHEAST OUT OF THE OHIO VALLEY. A 2-3 SIGMA 850MB WESTERLY JET WILL SLIDE ACROSS THE SOUTHERN HALF OF PENN THROUGH THE MIDDAY HOURS...AND WILL SUPPORT AN INITIALLY COMPACT AREA OF 3-4 SIGMA 850 MB MOISTURE FLUX. THIS AREA OF BETTER MOISTURE AND STRONGER FORCING WILL COVER ABOUT THE SE THIRD OF THE STATE AT 18Z. POCKETS OF MDTLY HIGH ML CAPES OF 1000-1500 J/KG WILL DEVELOP DURING THE LATE MORNING AND AFTERNOON HOURS ACROSS THE SOUTHERN THIRD OF THE STATE...WHILE MUCH MORE STABLE AIR ADVECTS INTO THE NRN MTNS. SPC`S DAY 1 MARGINAL RISK AREA COVERS THE SE HALF OF PENN...BUT UPGRADED FAR SERN PENN (INCLUDING YORK AND LANCASTER COUNTIES) TO A SLIGHT RISK WITH THE MAIN SEVERE WEATHER THREAT COMING IN THE FORM OF ISOLATED STRONG/DAMAGING WESTERLY WIND GUSTS ATTRIBUTED TO 30-50 KT WINDS IN THE 850-700 MB LAYER...AND AN INVERTED-V SOUNDING. MODELS SHOWING LOCAL PREFRONTAL 1000 J/KG CAPES ALONG THE MASON-DIXON LINE LATER THIS MORNING/AFTN. TOTAL FCST RAINFALL FROM ABOUT MIDNIGHT MONDAY NIGHT THROUGH 6 PM TODAY WAS PAINTED TO BE A BIT HIGHER THAN A GEFS/SREF BLEND ACROSS APPROX THE SOUTHERN HALF OF THE CWA...GIVEN THE 6 HOURLY TOTALS THAT OCCURRED WITH THE MCS NOW TRACKING ACROSS WESTERN LAKE ERIE AND FAR NWRN OHIO. COOL AIR REACHES THE NORTHWEST BY LATE THIS MORNING...WITH HIGHS THERE ONLY REACHING NEAR 60F. FARTHER SOUTH ANOTHER WARM DAY WILL BE SEEN WITH HIGHS IN THE MID TO UPPER 70S FOR ONE MORE DAY ACROSS SOUTH CENTRAL AND SOUTHEAST PA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... LATEST...07Z HRRR IMPLIES THAT THE SFC COLD FRONT WILL SLIDE SOUTH OF THE I-76/78 CORRIDOR BEFORE DUSK...WITH LINGERING SHOWERS AND TSRA NEAR THE MASON/DIXON LINE INTO THIS EVENING. A SEVERAL HOUR PERIOD OF BKN-OVC STRATUS AND STRATO CU SHOULD FOLLOW THE CFROPA THROUGH LATE THIS EVENING...BEFORE DRIER AIR PUSHES IN FROM THE NORTH/NORTHEAST AND HELPS TO ERODE THE LOW CLOUD DECK. LOW TEMPS TONIGHT WILL RANGE FROM THE FROSTY LOWER 30S ACROSS THE NORTHERN TIER COUNTIES...TO THE MID AND UPPER 40S IN THE SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... WED LOOKS DRY AND COOLER...AS A NE FLOW OF DRY AIR BUILDS SOUTHWARD FROM A LARGE HIGH OVER WESTERN HUDSON BAY. A SYSTEM TRACKING SOUTH OF THE AREA ON THU WILL BRING SOME RAIN...AND MORE NOTABLY COOLER TEMPERATURES TO THE AREA. A SECOND WEAK SYSTEM TRACKING SOUTH OF THE AREA OUT OF WV MAY BRING SOME SHOWERS STILL ON FRIDAY. LEFT POPS IN. STILL SOME HINTS OF A JET MAX DROPPING SE ON SAT...BUT REALLY NO MOISTURE TO WORK WITH. THUS STILL EXPECT THE DAY TO BE DRY. MID SHIFT HAD SOME SHOWERS IN FOR LATER ON SUNDAY. YESTERDAY THE EC WAS TOO FAST...STILL THAT WAY TODAY. LEFT POPS IN BUT DID LOWER SOME FOR SUNDAY AND SUNDAY NIGHT. FOR SUNDAY NIGHT..DID EDGE TEMPERATURES DOWN A LITTLE. LOOKS WET AND COOL FOR MONDAY. DID NOT GO QUITE AS HIGH AS THE SUPERBLEND WITH THE POPS. CLEARING OUT LATER MONDAY NIGHT. OVERALL A PATTERN THAT FAVORS WETTER AND COOLER WEATHER THAN WE HAVE HAD LATELY. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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FIRST WAVE SLIDING THROUGH BRINGING AN ERODING AREA OF SHOWERS /AND EARLIER ISO THUNDER TO FAR WESTERN SECTIONS/. CONDITIONS REMAINING GENERALLY VFR ACROSS CENTRAL PA THOUGH VSBYS HAVE SLIPPED TO MVFR FOR A SHORT TIME IN THE EAST. EXPECT A MINIMUM OF SHOWER ACTIVITY MID/LATE MORNING...BUT CONVECTION SHOULD STEADILY EXPAND OVER CENTRAL MTNS AND DROP ACROSS SOUTHERN SECTIONS IN THE AFTERNOON AS A COLD FRONT DROPS ACROSS THE STATE. CAPE INCREASES MIDDAY...WHICH WILL BRING SCT TSTMS AS WELL. PRECIP WILL END FROM NW TO SE...EXITING THE LOWER SUSQ SHORTLY AFTER 00Z WED. LOWERING CIGS WILL SAG IN FROM THE NORTH...IMPACTING MAINLY WESTERN HIGHER TERRAIN AND LIKELY EXPANDING INTO THE CENTRAL MTNS TONIGHT. OUTLOOK... WED...NO SIG WX EXPECTED. THU-FRI...MVFR WITH SHRA LIKELY. SAT...FAIR.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...LAMBERT SHORT TERM...LAMBERT LONG TERM...LAMBERT/MARTIN AVIATION...RXR

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