495
FXUS61 KCTP 020553
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
153 AM EDT WED APR 2 2025
SYNOPSIS
LOW PRESSURE WILL TRACK WEST OF PENNSYLVANIA THROUGH THE GREAT
LAKES WEDNESDAY NIGHT INTO THURSDAY. THE TRAILING COLD FRONT
WILL PUSH THROUGH CENTRAL PENNSYLVANIA LATE THURSDAY, THEN STALL
OUT OUT OF JUST SOUTH OF THE REGION LATE THIS WEEK. A WAVE ON
THE STALLED FRONT IS LIKELY TO LIFT UP THE OHIO VALLEY AND
ACROSS PENNSYLVANIA NEXT WEEKEND.
NEAR TERM /THROUGH TODAY/
FAIR AND CHILLY CONDITIONS PREVAILING OVERNIGHT. VARIABLE MID
LEVEL CLOUDS INCREASING FROM THE OHIO VALLEY EARLY THIS MORNING
WON'T HAVE A BIG IMPACT ON MIN TEMPS. GOOD DECOUPLING FROM
EARLIER CLEAR SKIES COMBINED WITH LIGHT WIND AND DRY AIR WILL
STILL ALLOW MINS TO DROP BELOW NBM GUIDANCE, ESPECIALLY FAR EAST
WHERE SKIES REMAIN CLEAR AND INVERSION IS STRONGEST. EXPECT
DAYBREAK READINGS TO RANGE FROM THE MID 20S IN THE VALLEYS OF
NORTH- CENTRAL PA, TO THE MID 30S IN THE MORE URBANIZED SPOTS OF
THE LOWER SUSQ VALLEY.
ISENTROPIC LIFT AT THE NOSE OF A STRONG SOUTHERLY LOW LEVEL JET
LIFTING INTO THE GRT LKS WILL LIKELY PRODUCE A ROUND OF SHOWERS
ACROSS MUCH OF CENTRAL PA WED AFTERNOON/EARLY EVENING. THE
STRONGEST FORCING AND HIGHEST POPS OF AROUND 90 PCT ARE ACROSS
THE NW MTNS, WHILE THE LOWER SUSQ VALLEY STANDS THE LEAST CHANCE
OF MEASURABLE RAIN. LATEST CAMS INDICATE THE MOST LIKELY
TIMEFRAME FOR SHOWERS WILL RANGE FROM MID AFTERNOON OVER THE NW
MTNS, TO EARLY EVENING OVER THE EASTERN EDGE OF THE FORECAST
AREA. MOSTLY CLOUDY SKIES AND A SOUTHEAST FLOW OFF OF THE CHILLY
ATLANTIC OCEAN SHOULD RESULT IN MAX TEMPS WED A BIT BELOW
NORMAL FOR EARLY APRIL.
SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/
THE SHOWERS SHOULD LIFT NORTH OF THE PA/NY BORDER BY LATE WED
EVENING WITH THE RETREATING 8H BAROCLINIC ZONE. FOCUS THEN
SHIFTS TO AN UPSTREAM COLD FRONT AND ASSOCIATED LINE OF
CONVECTION, WHICH SHOULD PUSH INTO AT LEAST THE NORTHWEST PART
OF THE FORECAST AREA BY DAWN THURSDAY. CURRENT PROGS INDICATE
MINIMAL SURFACE BASED INSTABILITY, BUT 70KT WINDS AT 850MB
SUPPORTS A MRGL RISK OF DAMAGING WIND GUSTS TOWARD DAWN OVER
THE ALLEGHENY PLATEAU.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
SHOWERY AND MILD WEATHER IS EXPECTED THURSDAY, AS THE AREA
BRIEFLY BREAKS INTO THE WARM SECTOR AHEAD OF AN APPROACHING COLD
FRONT. 18Z EPS PLUMES SUGGEST THE BEST CHANCE OF PM SEVERE
WEATHER WILL BE ACROSS THE LOWER SUSQ VALLEY, WHERE MODERATE
INSTABILITY (CAPE NEAR 1000J/KG) IS PROGGED IN CONJUNCTION WITH
DEEP LAYER SHEAR OF AROUND 40KTS.
THE COLD FRONT IS THEN PROGGED TO STALL OUT JUST SOUTH OF PA
THURSDAY NIGHT. A WAVE ON THIS BOUNDARY LOOKS INCREASINGLY
LIKELY TO RESULT IN A PERIOD OF RAIN THURSDAY NIGHT INTO EARLY
FRIDAY, ESPECIALLY ACROSS NORTHERN PA.
LATEST EPS/GEFS SUGGESTS A BRIEF PERIOD OF COOL AND DRIER
WEATHER IS LIKELY FRIDAY/FRIDAY NIGHT ASSOCIATED WITH A SURFACE
HIGH PASSING NORTH OF PA. HOWEVER, MEDIUM RANGE GUIDANCE
INDICATES ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE STALLED
FRONT WILL RESULT IN A RAINY WEEKEND. LATEST ENSEMBLE MEAN QPF
BETWEEN THU NIGHT AND SUN PM RANGES FROM 1 TO 2.5 INCHES OVER
CENTRAL PA, WITH THE HIGHEST TOTALS FOCUSED OVER THE NW MTNS
AND THE LEAST ACROSS THE LOWER SUSQ VALLEY. THE SOUTHEASTERN
PART OF CENTRAL PA HAS BEEN UNDER MODERATE TO SEVERE DROUGHT
CONDITIONS FOR QUITE SOME TIME, SO ANY RAIN OVER THAT PART OF
THE STATE WOULD BE BENEFICIAL.
THERE IS BROAD CONSENSUS AMONG MEDIUM RANGE GUIDANCE THAT UPPER
TROUGHING BUILDS OVER THE REGION EARLY NEXT WEEK, ACCOMPANIED BY
BELOW NORMAL TEMPERATURES AND SCATTERED RAIN/SNOW SHOWERS OVER
THE ALLEGHENY PLATEAU. BELOW AVERAGE TEMPS ARE FAVORED FOR MUCH
OF NEXT WEEK, WHICH COULD RAISE SOME FROST/FREEZE CONCERNS AS
THE SPRING GROWING SEASON GETS UNDERWAY.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
VFR CONDITIONS CONTINUE THROUGH THE REST OF THE NIGHT AND MUCH
OF THE DAY ON WEDNESDAY AS HIGH CLOUDS STREAM IN AHEAD OF AN
APPROACHING WARM FRONT. WINDS WILL REMAIN LIGHT INTO THE FIRST
HALF OF THE MORNING BEFORE GUSTS OF 20 TO 30 KNOTS BECOME
LIKELY. A BAND OF SHOWERS IS EXPECTED TO DEVELOP DURING THE
AFTERNOON/EVENING, WITH BFD MOST LIKELY TO SEE RAIN. ALL OTHER
SITES HAVE AROUND A 30% CHANCE OR LESS OF SEEING MEASURABLE
RAINFALL. ANY AIRFIELDS THAT DO SEE SHOWERS MAY HAVE BRIEF
PERIODS OF MVFR CIGS/VSBY. A FEW RUMBLES OF THUNDER WILL ALSO BE
POSSIBLE OVER NORTHWEST PA WITH WEAK INSTABILITY SHOWN IN MOST
MODELS.
AS SHOWERS MOVE OUT OF THE REGION, MOST GUIDANCE INDICATES THAT
SOUTH-SOUTHEASTERLY FLOW WILL LEAD TO INCREASING LOW-LEVEL
MOISTURE OVER MUCH OF CENTRAL PA. THIS WILL CAUSE MVFR CEILINGS
TO DEVELOP ALMOST EVERYWHERE WEDNESDAY NIGHT, WITH THE POTENTIAL
EXCEPTION OF JST. RAP MODEL SOUNDINGS SUGGEST THAT THE LOW
CLOUDS WOULD MAKE IT THERE, BUT THE GLAMP AND HREF SHOW A LESS
THAN 40% CHANCE OF MVFR CEILINGS DEVELOPING.
THE OTHER CONCERN INTO WEDNESDAY NIGHT WILL BE LLWS AS A 45 TO
55 KNOT LOW-LEVEL JET MOVES IN AND SURFACE WIND GUSTS DECREASE.
BFD WILL BE THE FIRST AIRFIELD TO SEE WIND SHEAR DEVELOP AND THE
THREAT WILL SPREAD SOUTHEASTWARD THROUGH THE LATE EVENING. THE
POTENTIAL FOR LLWS WILL REACH MDT AND LNS IN THE 06-08Z
TIMEFRAME.
OUTLOOK...
THU...MVFR POSS IN WIDESPREAD RAIN SHOWERS. TSRA POSS, MAINLY S.
CFROPA AFTN/EVE.
FRI...MVFR CIGS AND VISBY EXPECTED, MAINLY S.
SAT...WIDESPREAD SHOWERS; IMPACTS LIKELY.
SUN...WIDESPREAD SHOWERS; IMPACTS LIKELY.
CLIMATE
CLOSING OUT VERY MILD MARCH 2025. BELOW ARE THE RANKINGS AND
DEPARTURES FROM THE HISTORICAL AVERAGE THROUGH 3/30:
SITE AVG. MARCH TEMP RANK
HARRISBURG 46.5F (+4.9F) 12TH WARMEST
WILLIAMSPORT 44.8F (+6.2F) 9TH WARMEST
ALTOONA 44.4F (+5.9F) 7TH WARMEST
BRADFORD 40.2F (+7.3F) T3RD WARMEST
STATE COLLEGE COOP SITE STCP1 RECORDED THE 10TH WARMEST MARCH ON
RECORD WITH AN AVERAGE MONTHLY TEMPERATURE OF 43.3F.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...DEVOIR/FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...BAUCO
CLIMATE...STEINBUGL
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