560
FXUS61 KCTP 280616
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
216 AM EDT TUE APR 28 2026
WHAT HAS CHANGED
* INCREASED WIND GUSTS IN THE FAR NORTH FOR LATER TONIGHT
KEY MESSAGES
1) PERIODS OF RAIN TUESDAY AND WEDNESDAY
2) PATTERN SHIFTS TO COLD LATER THIS WEEK WITH BELOW AVERAGE
TEMPERATURES INTO EARLY MAY
DISCUSSION
KEY MESSAGE 1: PERIODS OF RAIN TUESDAY AND WEDNESDAY
MINOR CHANGE TO ADD UP TO 10MPH ONTO THE WIND GUSTS FOR LATER
TONIGHT AS THE 50KT LLJET DIPS VERY CLOSE TO THE SFC (AROUND
1KFT UP). THE LIGHT SHOWERS/EVAP COOLING ALOFT MOVING IN COULD
HELP TRANSPORT SOME PORTION OF THAT MOMENTUM DOWN TO THE SFC.
HOWEVER, WE DIDN'T GO TO 40KT WITH THEM, AS THE STABILITY SHOULD
BE ENOUGH TO MITIGATE/DIMINISH THE THREAT OF ANYTHING >40KT/WIND
ADVY. THIS IS A REGULAR TROUBLE TO HAVE IN THE FORECAST.
LOCATIONS ALONG THE ERIE LAKESHORE CAN TAP THAT HIGHER MOMENTUM
THANKS TO THE DOWNSLOPE TO HELP IT MIX DOWN. BUT, OUR PLACE ON
THE BROADER ALLEGHENY PLATEAU USUALLY MAKES IT MORE DIFFICULT
FOR THOSE FASTER S/SERLY WINDS ALOFT TO MIX DOWN.
PREVIOUS...
THE PREPONDERANCE OF MODEL DATA SUPPORTS TWO PERIODS OF WET
WEATHER TUESDAY AND WEDNESDAY. QPF AMOUNTS ARE MORE ROBUST ON
WEDNESDAY TIED TO STRONGER FRONTAL WAVE WITH 48-HR TOTALS IN
THE 0.75-1.50" RANGE ENDING 12Z THURSDAY. THIS RAIN WILL
CONTINUE TO ADD TO SURPLUSES OVER THE NW HALF OF THE AREA WHILE
HELPING TO REDUCE RAINFALL DEFICITS IN THE SOUTHERN 1/3 OF CPA
WHERE D1-D2 DROUGHT AREAS HAVE BEEN PERSISTENT. HOWEVER LIKE
WE'VE SEEN TIME AND TIME AGAIN SO FAR THIS YEAR, THE HIGHEST
TOTALS ARE EXPECTED IN THE NORTHWEST.
SPC D3 MRGL RISK VALID WEDNESDAY CLIPS THE LAURELS AS A 1003 MB
SFC LOW SWINGS THROUGH THE AREA. GUIDANCE SEEMS TO SUGGEST ONLY
LIMITED AMOUNTS OF INSTABILITY, CONFINED TO SW PA. NBM HAS
70-80% CHC OF AT LEAST 200 J/KG SBCAPE IN SW PA BUT ONLY A 30%
CHC OF 750+ J/KG. STORM MOTIONS WOULD BE TO THE NORTHEAST, SO
STORMS WOULD BE MOVING INTO A LESS FAVORABLE ENVIRONMENT AS THEY
MOVE INTO PA. LARGE SCALE FORCING WILL BE FAVORABLE FOR ASCENT
FOR 6-12 HOURS ACROSS ALL OF CENTRAL PA AS WE'LL BE BENEATH THE
LEFT EXIT REGION OF AN UPPER JET MAX.
--------------------------------------------------------------
KEY MESSAGE 2: PATTERN SHIFTS TO COLD LATER THIS WEEK WITH
BELOW AVERAGE TEMPERATURES INTO EARLY MAY
LATEST GUIDANCE HAS A GOOD HANDLE ON THE MID-LARGER SCALE
PATTERN EVOLUTION FROM LATE WEEK INTO THE WEEKEND (END OF APRIL
INTO EARLY MAY) SHOWING A BROAD UPPER TROUGH/LOW OVER THE GREAT
LAKES INTO THE NORTHEAST. THIS UNSEASONABLY COOL CYCLONIC FLOW
PATTERN WILL DELIVER BELOW NORMAL TEMPS (5-15 DEGREES) AND MAINTAIN
DAILY SHOWER CHANCES WITH BREEZY CONDITIONS (WIND GUSTS 25-35
MPH) THURSDAY THROUGH SUNDAY. ODDS FAVOR ADVECTIVE FREEZE OVER
FROST RISK WITH WIND AND CLOUD COVER PLAYING A KEY FACTOR.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS CONTINUE THROUGH THE MID MORNING HOURS TODAY ACROSS
THE WESTERN MTNS OF PA, UNTIL THE EARLY AFTERNOON HOURS
THROUGHOUT THE CENTRAL MOUNTAINS AND LIKELY THROUGH THE MID
AFTERNOON HOURS OVER THE LOWER SUSQ VALLEY.
IN THE MEANTIME, CENTRAL AND WESTERN PA AIRFIELDS WILL FEEL THE
IMPACT OF A SOUTHERLY LOW-LEVEL JET LEADING TO LOW-LEVEL WIND
SHEAR. THE LONGEST PERIODS OF LLWS WILL BE AT KBFD, KJST, KAOO
AND KUNV - THROUGH 18-20Z TODAY. PEAK SOUTHERLY WINDS AROUND THE
2000 FT AGL LEVEL WILL BE BETWEEN 45-50 KT AT KBFD DURING THE
MID TO LATE MORNING, AND IN THE LOW 40 KT RANGE FROM KJST TO
KAOO AND KUNV WITH VALUES BETWEEN 35-40 KTS OVER THE SUSQ
VALLEY.
CIGS DROP TO IFR BY 20-21Z OVER THE AIRFIELDS OF KJST AND KBFD
AND AROUND DUSK (01Z WED) AT KUNV. THE AIRFIELDS OF KAOO, KIPT,
KMDT AND KLNS SHOULD ONLY DROP TO MVFR - CIG-WISE.
THE PROBABILITY FOR SHOWERS TODAY WILL VARY FROM 60-75 PERCENT
OVER THE CENTRAL AND WESTERN MTNS TO 40-55 PERCENT OVER THE
LOWER AND MID SUSQ VALLEY RESPECTIVELY.
OUTLOOK...
WED...MVFR/IFR FAVORED DUE TO LOW CLOUD CEILINGS & RAIN
OVERSPREADING THE REGION.
THU...VFR/MVFR OVERNIGHT AS RAIN ENDS WEST TO EAST, BECOMING
VFR IN THE AFTERNOON.
FRI-SAT...MAINLY VFR WITH BRIEF RESTRICTIONS POSSIBLE IN
SHOWERS.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...DANGELO/COLBERT
KEY MESSAGES...DANGELO/COLBERT
DISCUSSION...DANGELO/COLBERT
AVIATION...LAMBERT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page