085
FXUS61 KCTP 311127
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
727 AM EDT SAT MAY 31 2025
SYNOPSIS
* SHOWERS AND THUNDERSTORMS ON SATURDAY AS A COLD FRONT MOVES
ACROSS THE REGION WITH SEVERE POTENTIAL ACROSS SOUTHEASTERN
PENNSYLVANIA.
* DRY CONDITIONS PREVAIL FOR THE FIRST HALF OF THE WEEK BEFORE
A RETURN TO SHOWERS AND THUNDERSTORMS MID-TO-LATE NEXT WEEK.
* TEMPERATURES WELL-BELOW AVERAGE TODAY TREND WARMER INTO NEXT
WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
SURFACE LOW-PRESSURE HAS MOVED NORTHEAST OF THE REGION WITH
MUCH OF THE PRECIPITATION PREVIOUSLY STATIONED OVER EASTERN
PENNSYLVANIA EAST OF THE FORECAST AREA. SURFACE COLD FRONT
BEGINS ENTERING W PA DURING THE EARLY MORNING HOURS, ALLOWING
FOR ANOTHER SHOWER- FILLED DAY ACROSS MUCH CENTRAL PENNSYLVANIA.
INSTABILITY EARLY ON IN THE DAY REMAINS EXTREMELY LIMITED, WITH
MINIMAL RECOVERY IN INSTABILITY. SOME INITIAL CLEARING ACROSS
SOUTH- CENTRAL/SOUTHEASTERN PENNSYLVANIA WILL ALLOW FOR A BRIEF
PERIOD OF DESTABILIZATION WITH RECENT HREF GUIDANCE OUTLINING
CAPE VALUES BETWEEN ~500-600 J/KG AND AMPLE LIFT AND MARGINAL
SHEAR. THE COMBINATION OF THESE FACTORS LEADS TO A MARGINAL RISK
FOR SEVERE THUNDERSTORMS MAINLY SOUTHEAST OF THE I-81 CORRIDOR
THIS EVENING.
GRADIENT WINDS IN THE WAKE OF THE SURFACE LOW-PRESSURE WILL
ALLOW FOR A BREEZY CONDITIONS THROUGHOUT THE DAY TODAY. SURFACE
COLD FRONT WILL BRING ABOUT LOCALIZED ENHANCEMENT OF GUSTY
WINDS THROUGHOUT THE LATE MORNING INTO THE EVENING HOURS.
SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/
DRIER AIR IN THE WAKE OF THE COLD FRONT WITH REINFORCING COLD
AIR UNDER NORTHWESTERLY FLOW WILL LEAD TO COOLER TEMPERATURES
SATURDAY NIGHT INTO SUNDAY MORNING, WITH TEMPERATURES WELL-BELOW
AVERAGE TO START OFF JUNE. COOLER TEMPERATURES ONCE AGAIN
PREVAIL SUNDAY NIGHT INTO MONDAY WITH A GRADUAL WARMING TREND
THROUGH TUESDAY, WITH TEMPERATURES REVERTING CLOSER TO
CLIMATOLOGICAL AVERAGES.
LINGERING SHOWERS AND THUNDERSTORMS IN THE BEGINNING PORTIONS OF
THE SHORT-TERM WILL GRADUALLY EXIT EAST OF THE AREA. DRY
CONDITIONS GRADUALLY PREVAIL BY MONDAY MORNING AND THROUGH THE
END OF THE SHORT-TERM WITH HIGH PRESSURE BUILDING INTO THE
REGION.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
DRY CONDITIONS ARE EXPECTED TO CONTINUE ON WEDNESDAY AS
GUIDANCE AGREES ON A BUBBLE OF HIGH PRESSURE FENDING OFF
MOISTURE. THE MAXES SHOULD GET INTO THE 80S FOR WEDNESDAY AND
THURSDAY. SOME URBAN LOCATIONS COULD TOUCH 90F WED AFTN. THE
NEXT COLD FRONT MAY BRING SOME SHOWERS AND PERHAPS A
THUNDERSTORM OR TWO TO THE AREA NEXT THURSDAY. THE UPPER FLOW
THEN STAYS OUT OF THE SW WITH A RIDGE OFF THE COAST. THAT WILL
ALLOW A MORE OR LESS CONTINUOUS FLOW OF MOISTURE INTO THE AREA
FOR THE WEEKEND. (READ: SHOWERS/TSTORMS)
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
LINGERING LIGHT RAIN ACROSS EASTERN PA WILL PULL AWAY FROM THE
AREA THIS MORNING. HOWEVER, ADDITIONAL SHOWERS ARE ALREADY
POPPING UP OVER WESTERN PA AND THESE WILL PROGRESS EASTWARD
ACROSS THE REGION TODAY.
A GUSTY W/NW WIND HAS DEVELOPED AND WILL PERSIST THROUGH THE DAY
AS WELL, OCCASIONALLY GUSTING 20-30 KTS.
SKIES WILL GRADUALLY CLEAR THIS EVENING INTO THE OVERNIGHT,
WITH PREDOMINANTLY VFR CONDS EXPECTED FOR SUNDAY.
OUTLOOK...
SUNDAY...MAINLY VFR WITH BREEZY NORTHWESTERLY WINDS.
MONDAY-WEDNESDAY...MAINLY VFR.
CLIMATE
MAY 2025 PRECIPITATION RANKINGS
SITE MAY 1-30, 2025 | WETTEST MAY ON RECORD
-----------------------------------------------------------
HARRISBURG 9.72" WETTEST | 9.71" IN 1989 (PREVIOUS)
WILLIAMSPORT 6.99" 5TH WETTEST | 9.91" IN 1919
ALTOONA 7.24" 3RD WETTEST | 7.31" IN 1960
STATE COLLEGE 6.47" 9TH WETTEST | 9.45" IN 1894 (~5/29)
RECORD PRECIPITATION WAS OBSERVED IN HARRISBURG ON MAY 30TH
WHEN 1.75 INCHES OF PRECIPITATION OCCURRED. THIS BROKE THE
PREVIOUS RECORD OF 1.39 INCHES SET BACK IN 1953. FOR REFERENCE,
A CONTINUOUS WEATHER RECORD HAS BEEN KEPT IN HARRISBURG SINCE
1888.
RECORD PRECIPITATION WAS ALSO OBSERVED AT JOHNSTOWN, WHERE 1.05
INCHES OF PRECIPITATION OCCURRED, BREAKING THE OLD RECORD OF
0.89 INCHES SET BACK IN 1975.
A SEASONABLY STRONG/DEEP AREA OF LOW PRESSURE (~990MB) IS
FORECAST TO MOVE ACROSS SOUTHEASTERN PENNSYLVANIA OVERNIGHT. THE
RECORD LOW PRESSURE FOR MAY AT HARRISBURG IS 983.4MB.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...NPB
NEAR TERM...NPB
SHORT TERM...NPB
LONG TERM...DANGELO/MARTIN
AVIATION...EVANEGO/TYBURSKI
CLIMATE...STEINBUGL/NPB
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