Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 020640
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
240 AM EDT THU APR 2 2015

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE DELMARVA COAST EARLY TODAY...AND
MUCH WARMER AIR WILL MOVE INTO THE REGION AS A SOUTHWESTERLY FLOW
DEVELOPS AHEAD OF AN APPROACHING FRONTAL BOUNDARY. THIS FRONT
SHOULD STALL OUT ACROSS PENNSYLVANIA TOMORROW INTO SATURDAY...
ALLOWING A SIGNIFICANT WAVE OF LOW PRESSURE TO FORM AND RIDE
NORTHEAST ALONG IT...BRINGING RAIN THEN PERHAPS A CHANGEOVER TO
WET SNOW ACROSS CENTRAL AND NORTHWESTERN PENNSYLVANIA.

&&

.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE CENTERED JUST EAST OF NORFOLK VA AT 06Z WILL MOVE
OUT TO SEA THIS MORNING. MAINLY CLEAR SKIES WILL PREVAIL...WITH
JUST SOME AREAS OF GENERALLY THIN CIRRUS SPILLING SOUTHEAST FROM
THE GREAT LAKES REGION.

WINDS WILL STAY MAINLY LIGHT AND VARIABLE THIS MORNING.

LOW TEMPS WILL RANGE FROM THE 20S ACROSS THE NORTHERN MTNS WHERE
AREAS OF LIGHT SNOW COVER REMAIN /ESPECIALLY ON THE NORTH-FACING
SLOPES/...TO THE LOWER AND MID 30S ACROSS THE SOUTH.

MID AND HIGH CLOUDS GRADUALLY INCREASE/THICKEN-UP FROM THE WEST
THIS AFTERNOON AND EVENING. SOME SHOWERS WILL MOVE INTO THE
WESTERN MTNS AFTER 18Z...WITH AN OUTSIDE CHC FOR A TSRA SNEAKING
INTO THE FAR NW ZONES THIS EVENING /WITHIN AN AXIS OF HIGHER...1
TO 1.25 INCH PWAT AIR JUST AHEAD OF AN APPROACHING COLD FRONT.

PRIOR TO THAT...WE SHOULD SEE TEMPS REACH THE UPPER 50S TO MID
60S /NW TO SE ACROSS THE CWA/. SOUTH TO SOUTHWEST WINDS WILL
INCREASE THIS AFTERNOON...ESP ACROSS THE HIGHER TERRAIN OF WRN
PENN WHERE GUSTS INTO THE 25 TO 30KT RANGE ARE LIKELY.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
SFC COLD FRONT AND AXIS OF HIGH PWAT AIR SLIDES GRADUALLY EAST
ACROSS THE STATE TONIGHT. ISOLATED TO SCATTERED SHRA WILL OCCUR OUT
AHEAD OF THE FRONT...WITH MORE NUMEROUS SHOWERS OCCURRING
ALONG...AND JUST TO THE WEST OF THE BOUNDARY /WHICH PLACES THE
BULK OF THE PRECIP ACROSS THE NW HALF OF THE STATE THROUGH 12Z
FRIDAY.

IT APPEARS THAT THE FRONT WILL STALL OUT FROM THE SRN POCONOS OR
LEHIGH VALLEY DURING THE DAY FRIDAY...WITH SHOWERS OR A FEW
PERIODS OF STEADIER RAIN TEMPORARILY BECOMING CONFINED TO THE
SOUTHERN HALF OF PENN.

RAIN SPREADS NE ACROSS THE ENTIRE REGION LATE FRIDAY/FRIDAY NIGHT
AS A SIGNIF WAVE OF LOW PRESSURE FORMS OVER THE LOWER OHIO RIVER
VALLEY AND DEEPENS TO SUB 1000 MB AS IT MOVES ACROSS CENTRAL OR
SRN PENN EARLY FRIDAY NIGHT. A MULTI- MODEL AND ENSEMBLE BLEND OF
QPF AMOUNTS WITH LOCAL BIAS CORRECTION RESULTS IN WIDESPREAD 0.50
TO 1 INCH AMOUNTS WITH THE POTENTIAL FOR 1-2 INCH TOTALS OVER THE
WRN 1/3 OF THE CWA. THESE AMOUNTS COULD PRODUCE SOME MINOR
FLOODING AND WPC HAS ISSUED A SLIGHT RISK FOR EXCESSIVE RAFL
TARGETING WRN/SWRN PA. AS THE LOW DEEPENS WHILE LIFTING TOWARDS
THE NORTHEAST FRIDAY NIGHT...A DEFORMATION ZONE IS FORECAST TO
BECOME ESTABLISHED OVER NW PA/WRN NY INTO INTERIOR NEW ENGLAND.

THE AIR SHOULD BECOME COLD ENOUGH TO SUPPORT A MIX WITH...OR
CHANGEOVER TO ALL SNOW ACROSS FAR NWRN PENN WITH A FEW TO SVRL
INCHES POSSIBLE OVERNIGHT FRIDAY NIGHT. WILL CONTINUE TO HIGHLIGHT
THE POTENTIAL IMPACT OF THIS LIGHT TO MDT WET SNOWFALL IN THE
HAZARDOUS WEATHER OUTLOOK /HWOCTP/.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LOW PRESSURE MOVES FROM THE SUSQ VALLEY OF PENN TO THE SRN NEW
ENGLAND COAST BETWEEN 03Z-12Z SAT. SHORTWAVE ENERGY PRESSING SEWD
FROM THE GREAT LKS TOWARD THE COAST PUSHES THE FRONT THROUGH OUR AREA
BY 12Z SATURDAY.

A PERIOD OF GUSTY NW WINDS ON THE BACKSIDE OF THE DEPARTING LOW
WILL LEAD TO AN UNSEASONABLY COLD AND BRISK START TO THE EASTER
WEEKEND WITH BELOW NORMAL TEMPERATURES...TRENDING WARMING INTO
THE MIDDLE OF NEXT WEEK. THE PATTERN SHOULD DRY OUT FOR THE MOST
PART WITH ANOTHER POTENTIAL WET PERIOD AROUND 7-8 APRIL.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
06Z TAFS SENT.

ADDED LLWS FOR EARLY TODAY...GIVEN FCST INCREASE IN WIND SPEEDS
AND THAT VAD WINDS ON THE RADAR ARE ALREADY IN THE 30 TO 40
KNOT RANGE.

WINDS WILL BE GUSTY LATER TODAY...AS FIRST WAVE OF SHOWERS
MOVE INTO RATHER DRY AIR.

EARLIER DISCUSSION BELOW.

HIGH PRESSURE BUILDING EAST INTO PA FROM THE OHIO VALLEY. SKIES
HAVE CLEARED AND THOUGH WINDS ARE LIGHT...IT SHOULD BE TO DRY FOR
ANY REDUCING FOG/MIST TO FORM. VFR CONDS EXPECTED OVERNIGHT AND
THROUGH THE FIRST HALF OF THURSDAY. HOWEVER THERE SHOULD BE LOWERING
CONDITIONS TO MVFR WITH SCATTERED RAIN SHOWERS...AS A COLD FRONT
MOVES EASTWARD. GUSTY SW WIND DEVELOPING AND POSSIBLE LLWS AT
MDT...LNS...BFD AND JST. THIS IS DUE TO A STRONG LOW LEVEL JET
THAT SHOULD BE STRONG ACROSS THE SOUTHEAST AND THROUGH THE WESTERN
HIGHER ELEVATION SITES.

OUTLOOK...

SAT...LOW PROB FOR RAIN SHOWERS /MIXED WITH SNOW SHOWERS NORTH/.
REDUCTIONS POSS MAINLY NORTHERN MTNS.

SUN...MAINLY VFR. FRONT WILL APPROACH FROM THE NORTH LATE IN THE
PERIOD.

MON..POSSIBLE AREA WIDE REDUCED CIGS AND VSBYS IN PCPN.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/STEINBUGL
AVIATION...CERU/MARTIN


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