Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 280753 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 353 AM EDT THU APR 28 2016 .SYNOPSIS... CLOUDS WILL THICKEN-UP FROM THE WEST THIS MORNING. AN AREA OF LOW PRESSURE WILL RIPPLE ALONG A STATIONARY FRONT THAT WILL BE LOCATED JUST TO THE SOUTH OF PENNSYLVANIA. THIS WEATHER FEATURE WILL SPREAD RAIN OVER THE AREA TODAY...AND PERIODS OF LIGHT RAIN OR DRIZZLE WILL CONTINUE TONIGHT INTO FRIDAY. SATURDAY WILL WILL BE FAIR BUT ON THE COOL SIDE BEFORE MORE RAIN MOVES IN FOR SUNDAY. RAIN COULD LINGER INTO LATE MONDAY OR EARLY TUE. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... A SHIELD OF MID AND HIGH CLOUDS WILL ADVANCE NORTHEAST ACROSS THE REGION EARLY TODAY...BEFORE LOWERING AND THICKENING ENOUGH TO SUPPORT RAIN DEVELOPING /DURING THE MID TO LATE MORNING ACROSS THE SW HALF OF THE CWA...AND MAINLY THIS AFTERNOON ACROSS THE NE/. SOME PATCHY -DZ MAY DEVELOP EVEN EARLIER OVR THE HIGH TERRAIN OF THE SC MTNS...WHERE UPSLOPE FLOW RESULTING IN RAP SFC-850 RH VALUES CLOSE TO 100 PCT AFTER 06Z. THIN SPOTS IN THE CIRRUS SHIELD...ALONG WITH LGT WIND AND DRY AIR SHOULD ALLOW TEMPS TO FALL TO INTO THE 30S ACROSS THE NCENT MTNS...WHILE M/U40S WILL BE MOST LIKELY ACROSS THE SOUTHERN COUNTIES. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/... A WAVE OF LOW PRESSURE...OR POSSIBLY EVEN A SERIES OF RELATIVELY WEAK WAVES WILL HEAD ENE UP THE OHIO RIVER VALLEY TODAY...AND BRING AN AREA OF WARM ADVECTION WITH PERIODS OF COLD RAIN DEVELOPING TODAY. BLENDED/CONSENSUS SHORT RANGE AND HIGH RES MODEL GUIDANCE INDICATES THAT THE WARM FRONT WILL STAY JUST SOUTH OF PA...GIVEN THE PROJECTED LOW LEVEL LIFTED INDICES PROGGED OVER THE REGION...SO HIGHS WITH THE OFF AND ON RAIN SHOULD ONLY AVERAGE IN THE LOW 50S...WELL BLW AVG FOR LATE APRIL. BASED ON 18Z/00Z OPER AND LATEST ENSEMBLE GUIDANCE...WILL MAINTAIN HIGH 12 HOUR POP GRIDS - NEAR 100 PCT ACROSS THE AREA TODAY. AGAIN..MOST OF THE RAIN SHOULD FALL DURING THE LATE AM HOURS ACROSS THE SW COUNTIES...AND MAINLY DURING THE AFTN ACROSS THE NE COUNTIES. MDL BLENDED QPF INDICATING ARND A QUARTER INCH OF RAIN IS LIKELY BY THIS EVENING. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... STILL LOOKS LIKE A SECOND WEAK SYSTEM WILL TRACK JUST SOUTH OF THE AREA ON FRIDAY. THIS SYSTEM WILL LIKELY BRING A FEW MORE SHOWERS TO THE AREA...AS AN INVERTED TROUGH SETS UP. MOST OF SAT STILL APPEARS DRY AS THE RIDGE EXTENDING FROM THE CANADIAN HIGH REESTABLISHES ITSELF TEMPORARILY. OVERALL A PATTERN THAT FAVORS WETTER CONDITIONS AS WE MOVE TOWARD THE KICKOFF OF MAY. THE PERIOD FROM LATER SUNDAY INTO EARLY TUE WILL LIKELY RESULT IN AT LEAST SOME RAIN AS A FAIRLY WELL-ORGANIZED AREA OF LOW PRESSURE MOVES NE FROM THE OHIO RIVER VALLEY. OVERALL NOT LOOKING REAL COLD...AS MAYBE THE GUIDANCE HINTED AT THE OTHER DAY...BUT A WETTER PATTERN THAN WE HAVE SEEN LATELY. THE SYSTEM FOR MONDAY LOOKS SIMILAR TO THE THU-FRIDAY SYSTEM. DID NOT MAKE A LOT OF CHANGES...JUST MINOR. 06Z GFS WAS DRY COMPARED TO THE 00Z EC. MAIN THING I DID WAS TO GO MAINLY DRY LATER TUE...AND NOT REAL HIGH WITH POPS ON WED. SUPERBLEND TEMPS FOR WED LOOK GOOD. THE LEADING EDGE OF THE REAL COLD AIR WITH THE POLAR VORTEX NOT FAR AWAY...AS SECONDARY COLD FRONT WILL BE OVER CENTRAL ONTARIO ON WED. THE 12Z GFS MORE IN LINE WITH WITH KEEPING SOME RAIN ACROSS THE REGION FROM TIME TO TIME...AS I HAVE SEEN LATELY. INTERESTING TO NOTE...LAST MAY STARTED OFF WARM...NEW 12Z EC FOR DAY 10 LOOKING MORE LIKE WINTER THIS YR. && .AVIATION /07Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE WILL KEEP VFR CONDITIONS OVER THE NORTHERN AND MOST CENTRAL PA TERMINALS OVERNIGHT. HOWEVER CALMER WINDS AND LOW DEWPOINT DEPRESSIONS HAVE ALLOWED FOR LOW LEVEL STRATO CU TO FORM OVER THE SOUTHERN VALLEY TAF LOCATIONS...AOO...MDT AND LNS. EXPECT MVFR TO IFR CIGS AND VSBYS BETWEEN 07Z TO 12Z. THERE WILL BE A BRIEF BREAK IN LOW CLOUDS HOWEVER MORE UNSETTLED WEATHER WILL ARRIVE THURSDAY INTO FRIDAY AS AN AREA OF LOW PRESSURE MOVES OUT OF THE OHIO RIVER VALLEY SLIDING BY JUST TO THE SOUTH OF PENNSYLVANIA. THIS WILL BRING PERIODS OF RAIN AND MORE WIDESPREAD IFR/MVFR TOMORROW AFTERNOON AND EVENING. OUTLOOK... FRI...MVFR WITH OCCASIONAL RAIN. SAT...MAINLY VFR. SUN-MON...WIDESPREAD MVFR/IFR WITH OCCASIONAL RAIN. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LAMBERT NEAR TERM...FITZGERALD/LAMBERT SHORT TERM...FITZGERALD/LAMBERT LONG TERM...MARTIN AVIATION...LA CORTE/CERU

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