719
FXUS61 KCTP 300055
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
855 PM EDT THU MAY 29 2025
SYNOPSIS
* VARIABLY CLOUDY SKIES AND WARMER THIS AFTERNOON WITH A FEW
RAIN SHOWERS THIS EVENING INTO TONIGHT, PARTICULARLY ACROSS
SOUTHEASTERN ZONES
* PERIODS OF RAIN AND A FEW THUNDERSTORMS EXPECTED FRIDAY
AFTERNOON THROUGH SATURDAY EVENING
* BREEZY AND COOLER START TO THE WEEKEND/LAST DAY OF MAY
FOLLOWED BY A DRYING TREND AND SUMMERTIME WARMUP INTO THE
MIDDLE OF NEXT WEEK
NEAR TERM /UNTIL 8 AM FRIDAY MORNING/
CLOUD COVER IS STEADILY BUILDING IN THIS EVENING WITH SOUTHERLY
FLOW BRINGING DEEPER MOISTURE INTO CPA FOR THE OVERNIGHT HOURS.
HIRES MODEL DATA SHOWS SOME LIGHT RAIN SHOWERS TRACKING FROM
WEST TO EAST ACROSS CPA FROM EARLY THIS EVENING THROUGH TONIGHT.
SPARSE COVERAGE TRANSLATES INTO MOST LOCATIONS STAYING DRY WITH
MAX POPS ALONG THE MD LINE ESPECIALLY NEAR AND TO THE EAST OF
I-81. TONIGHT WILL BE MOSTLY CLOUDY WITH LOW TEMPS ABOUT +5
DEGREES ABOVE CLIMO IN THE 50-60F RANGE. PATCHY FOG COULD
DEVELOP IN PLACES TONIGHT ACROSS THE LOWER SUSQUEHANNA VALLEY
WHERE MOISTURE REMAINS HIGH BEHIND TONIGHT'S SHOWERS. WINDS
SHOULD REMAIN CALM ENOUGH OVERNIGHT GIVEN THE WEAK PRESSURE
GRADIENT AT THE SURFACE FOR PATCHY FOG, EVEN WITH CLOUDS
OVERHEAD TO LESSEN THE RADIATIONAL COOLING.
SHORT TERM /8 AM FRIDAY MORNING THROUGH SUNDAY/
LATEST CAMS SHOW DISAGREEMENT IN THE PLACEMENT OF THE SURFACE
LOW AS IT TRACKS ACROSS THE SOUTHEAST FRIDAY EVENING. THE
NORTHERN SOLUTION WOULD SUPPORT A FRONTOGENETIC BAND BRINGING
HEAVIER RAINFALL TO THE LOWER SUSQ VALLEY, WHILE A MORE
SOUTHWARD SOLUTION WOULD KEEP THE HEAVIEST RAIN IN MARYLAND.
EVEN SMALL SHIFTS IN THE TRACK OF THE LOW COULD BE ENOUGH TO
HAVE SIGNIFICANT IMPACTS ON THE LOCATION OF HIGHEST RAINFALL
AMOUNTS. THERE IS HIGHEST CONFIDENCE IN 1" TO 1.25" OF RAIN IN
THE LOWER SUSQUEHANNA VALLEY, WHICH WOULD BE BELOW THE THRESHOLD
OF CONCERN. HOWEVER, IF THAT CORRIDOR OF HIGHEST QPF SHIFTS
NORTHWARD THEN ADDITIONAL CONSIDERATIONS MAY BE MADE TOWARDS A
POSSIBLE FLOOD WATCH FOR THE SOUTHEAST.
PREVIOUS DISCUSSION...
THE LAST 2 DAYS OF MAY 2025 LOOK TO BE UNSETTLED AS A DEEP
TROUGH CARVES OUT ACROSS THE MID ATLANTIC REGION AND EASTERN US.
LATEST MODEL DATA FAVORS SHOWERS AND POSSIBLY A FEW
THUNDERSTORMS DEVELOPING ACROSS MUCH OF CENTRAL PA FRI
AFTERNOON, WITH MORE STRATIFORM RAIN DEVELOPING FRIDAY EVENING
INTO FRIDAY NIGHT AS 500MB HEIGHT FALLS WILL SPAWN A SFC LOW TO
THE EAST OF THE BLUE RIDGE BY 00Z SATURDAY. AN APPROACHING COLD
FRONT ON SATURDAY, COINCIDING WITH REINFORCING SHORTWAVE ENERGY
AND COOLING TEMPS ALOFT, WILL FAVOR A CONTINUATION OF FREQUENT
SHOWER/ISOT ACTIVITY ON SATURDAY AND COULD EVEN BE ENOUGH TO
SUPPORT A MARGINAL WIND/HAIL THREAT ACROSS SOUTHEAST PA. TEMPS
ON SATURDAY WILL LIKELY BE STUCK IN THE 50S ACROSS THE LAURELS
AND NORTHERN MOUNTAINS. THE WARMEST SPOT WILL LIKELY BE ACROSS
THE LOWER SUSQ VALLEY WITH HIGHS IN THE MID 60S. RAINFALL AMTS
BETWEEN FRI AND SAT ARE EXPECTED TO RANGE FROM NEAR 0.25" IN THE
NORTHWEST MOUNTAINS TO 0.50-1.0" ALONG THE I-80 CORRIDOR AND
PUSHING 1.25" ACROSS THE LOWER SUSQ VALLEY. LOCALLY HEAVIER
AMOUNTS POSSIBLE.
TYPICAL STRATOCU FIELD IS LIKELY TO COVER AREAS DOWNWIND OF
LAKE ERIE SATURDAY NIGHT INTO SUNDAY MORNING WITHIN THE BRISK NW
FLOW REGIME. APPARENT TEMPS EARLY SUNDAY MORNING ARE FORECAST
IN THE MID 30S/40S ACROSS MOST OF CPA - QUITE A CHILLY START TO
JUNE!
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
DECREASING WINDS AND CLEARING SKIES WILL RESULT IN ANOTHER
COLDER THAN NORMAL NIGHT SUNDAY NIGHT, WITH SOME POTENTIAL
FOR FROST. UNLIKE THIS PAST SUNDAY NIGHT, NOT SEEING MUCH
CHANCE FOR WINDS GOING CALM, SO MAYBE THIS FACTOR WILL HELP
OFFSET THE POTENTIAL FOR WIDESPREAD FROST ACROSS THE
NORTHWEST.
HIGH PRESSURE SFC AND ALOFT BUILDS ACROSS THE SOUTHEAST PART
OF THE COUNTRY EARLY NEXT WEEK, WILL RESULT IN TEMPERATURES
BEING MORE NORMAL FOR EARLY JUNE. TEMPERATURES COULD BE ABOVE
NORMAL AT TIMES IN THE NEXT WEEK OR TWO.
LOOKS LIKE MOST OF THE TIME SUNDAY INTO WEDNESDAY WILL BE DRY
NEXT WEEK. THE NEXT COLD FRONT MAY BRING SOME SHOWERS AND
PERHAPS A STORM TO THE AREA NEXT THURSDAY.
GETTING TO THAT TIME OF YEAR, WHERE COLD FRONTS COULD STALL
ACROSS THE SOUTHEAST PART OF THE KEYSTONE STATE, AS WESTERLIES
LIFT TO THE NORTH. THIS IS ESPECIALLY THE CASE IF AN UPPER LEVEL
LOW LINGERS TO OUR SOUTH.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR IS MAINLY BEING OBSERVED ACROSS MOST OF CENTRAL PA AS
HIGH CLOUDS CONTINUE TO BUILD IN ACROSS THE REGION AS MOISTURE
STREAMS IN FROM THE SOUTH.
DETERIORATING CONDITIONS ARE LIKELY AGAIN TONIGHT, ESPECIALLY AT
MDT AND LNS AS LOWER CIGS AND SOME FOG PUSHES IN FROM THE
SOUTH. THE CHANCE FOR IFR CONDITIONS LATE TONIGHT INTO EARLY FRI
MORNING IS ABOUT 50 PCT AT LNS AND 40 PCT AT MDT. SHOWERS ARE
ALSO LIKELY ACROSS THE SAME AREA. FARTHER NORTH/WEST, MOST
LOCATIONS ARE EXPECTED TO REMAIN VFR WITH THE EXCEPTION OF BFD,
WHERE MVFR CIGS ARE POSSIBLE (50 PCT CHC) MAINLY BETWEEN 06-14Z
FRI.
CONDITIONS WILL IMPROVE FROM LATE MORNING TO EARLY AFTERNOON ON
FRI, BEFORE DETERIORATING ONCE AGAIN LATER FRI AFTERNOON INTO
FRI NIGHT AS THE NEXT SYSTEM BRINGS PERIODS OF RAIN ACROSS THE
AREA, HEAVIEST IN THE SOUTHEAST.
OUTLOOK...
FRIDAY AND FRIDAY NIGHT...SOME AFTERNOON/EVENING RESTRICTIONS
IN SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS.
SATURDAY AND SATURDAY NIGHT...MAINLY MVFR. SCATTERED PM SHOWERS
AND PERHAPS A THUNDERSTORM OR TWO IN THE VICINITY OF LNS AND
MDT. GUSTY NORTHWEST WINDS.
SUNDAY...MAINLY VFR WITH GUSTY NORTHWEST WINDS.
MONDAY-TUESDAY...VFR.
CLIMATE
HARRISBURG TIED THE RECORD LOW-MAXIMUM TEMPERATURE OF 57 DEGREES
YESTERDAY 5/28. THE PREVIOUS RECORD LOW-MAX WAS SET IN 1996.
MAY 2025 PRECIPITATION RANKINGS
SITE MAY 2025 | WETTEST MAY ON RECORD
-----------------------------------------------------------
HARRISBURG 7.94" 4TH WETTEST | 9.71" IN 1989
WILLIAMSPORT 6.65" 8TH WETTEST | 9.91" IN 1919
ALTOONA 6.84" 4TH WETTEST | 7.31" IN 1960
STATE COLLEGE 6.47" 12TH WETTEST | 9.45" IN 1894
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...STEINBUGL/COLBERT
NEAR TERM...COLBERT/BOWEN
SHORT TERM...COLBERT/BOWEN
LONG TERM...MARTIN
AVIATION...COLBERT/BOWEN
CLIMATE...MARTIN/COLBERT
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