Strong afternoon heating of a moist air mass along and south of a retreating stationary front triggered isolated strong to severe thunderstorms across northern Pennsylvania. The thunderstorm environment was conducive for supercell structures, but no tornadoes were reported.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CTP wrote it up.
Strong afternoon heating of a moist air mass along and south of a retreating stationary front triggered isolated strong to severe thunderstorms across northern Pennsylvania. The thunderstorm environment was conducive for supercell structures, but no tornadoes were reported. The combination of moderate instability and marginal lapse rates resulted in occasional large hail ranging in size from nickel to golf ball.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS State College, PA wrote its last area forecast discussion before the first event at Apr 25, 11:25 AM EST, 3 hours 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 1225 PM EDT MON APR 25 2011 .SYNOPSIS... A NEARLY STATIONARY FRONT DRAPED ACROSS THE STATE WILL GRADUALLY LIFT NORTHWARD BY TUESDAY. A VERY MILD BUT UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH MOST OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... STATIONARY FRONT BISECTING PA FROM WEST TO EAST TODAY SLOWLY DRIFTING NOTHWARD. FORECAST CONTINUES ON TRACK FOR TODAY. CURRENT LULL IN THE SHOWER ACTIVITY ACROSS CENTRAL PA THIS NOONTIME...BUT DO EXPECT SHOWERS TO REFORM BY MID AFTERNOON...MOST NUMEROUS IN THE NORTHERN HALF OF CWA. ENOUGH CAPE TO GENERATE SOME SCT TSTORMS AS WELL WHICH COULD PRODUCE SOME GUSTY WINDS...BUT LAPSE RATES ARE MARGINAL. SPC DOES HAVE THE AREA IN A SLIGHT RISK FOR LATER TODAY. TEMPS WILL TOP OUT IN THE LOWER 80S ACROSS THE SOUTH WITH DEWPOINTS AROUND 60F. ON THE OTHER SIDE OF THE FRONTAL BOUNDARY...HIGHS ALONG THE NORTHERN TIER WILL ONLY REACH THE 60S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... THE FRONT WILL BE LIFTING NORTH OVERNIGHT WHICH SHOULD SHIFT THE FOCUS FOR THE BEST CHANCES OF RAIN NORTHWARD AS WELL. IT WILL BE A PRETTY MILD NIGHT IN MOST AREAS WITH IT EVEN BEGINNING TO FEEL A BIT MUGGY AS DEWPOINTS CREEP UP INTO THE 50S AND 60S. TUESDAY WILL BE WARM AND SOMEWHAT HUMID WITH SIMILAR INSTABILITY COOKING UP IN THE WARM SECTOR WITH DAYTIME HEATING. AS THE UPPER RIDGE BUILDS TWD THE NERN US AND CAN MARITIMES...OUR FLOW WILL TURN MORE SOUTHWESTERLY KEEPING ANOMALOUS WARMTH AND MOISTURE/PWATS ESTABLISHED OVER THE REGION. NAM/GFS MAKE A MESS OF THE MAINLY LIGHT CONVECTIVE QPF THAT THEY WANT TO PRETTY MUCH KEEP SCATTERED OVER THE REGION ALL DAY. THE CANADIAN AND ECMWF ARE MORE CONSERVATIVE EARLY IN THE DAY...WHICH LOOKS REASONABLE...BEFORE BUYING INTO SOMETHING THAT LOOKS MORE LIKE WHAT THE SREF DOES WITH THE BEST CHANCES OF PRECIP DEVELOPING IN THE AFTERNOON...MAINLY OVER THE WESTERN HALF OR SO OF THE FCST AREA. WITH GUIDANCE BEING PRETTY MUCH ALL OVER THE MAP...THAT PART OF THE FORECAST IS A LOW CONFIDENCE ONE. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE ALMOST PERPETUAL MENTION OF SHOWERS/STORMS WILL CONTINUE AT LEAST INTO THURSDAY WHEN THE GUIDANCE IS PRETTY GOOD AGREEMENT THAT A COLD FRONT WILL SWEEP THROUGH WITH COOLER-DRIER AIR FOR LATER IN THE WEEK INTO THE WEEKEND. TIMING DIFFERENCES FOR FRONTAL PLACEMENT FOR THURSDAY MORNING ARE RATHER SMALL GIVEN THE TIME RANGE AND ALL THE MODELS CONSIDERED. THE 00Z NAM IS SLOWEST SHOWING THE FRONT JUST ENTERING MY WESTERN ZONES AT 12Z...WITH THE OTHER MODELS BEING FASTER AND MUCH FURTHER EAST AT THE SAME TIME. 03Z SREF IS CLOSER TO THESE OTHER MODELS MAKING FOR A FASTER/EARLIER FROPA WHICH SHOULD MINIMIZE THE SEVERE THREAT BEING THAT IT SHUD BE COMING THROUGH AT OUR NORMALLY MOST STABLE TIME OF DAY. BEHIND FRONT...SOME COLDER AIR ALOFT WILL SLIDE IN ON FRI...BRINGING PLENTY OF CLOUDS AND SCT LIGHT SHOWERS...MAINLY OVER THE HIGH WESTERN TERRAIN AREAS. SATURDAY LOOKS FAIR AND MILD AS A SFC HIGH IS FCST TO MOVE THROUGH...WITH THE NEXT CHC OF RAIN ARRIVING SUNDAY WITH A NEW COLD FRONT. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... AS EXPECTED...JUST A FEW SHOWERS AND ISOLATED THUNDER ON EASTER SUNDAY. TEMPS WERE COOL ACROSS THE FAR NORTH...TO WARM ACROSS THE SE. FOR TODAY...NOT A LOT OF CHANGE. FRONT FROM SW PA TO NE PA WILL SLOWLY EDGE BACK TO THE NORTH. SOME SHOWERS WITH IT...PERHAPS A RUMBLE OF THUNDER. ALSO SOME PATCHY DENSE FOG EARLY THIS MORNING... AS SOME SPOTS HAVE CLEARED OUT...AND WINDS NOT AS STRONG AS YESTERDAY. AS THE WARM FRONT SLOWLY LIFTS NORTHWARD LATER TODAY...MUCH OF THE REMAINDER OF THE DAY WILL FEATURE JUST A FEW SHOWERS...ALONG WITH A CHANCE OF A THUNDERSTORM...WITH MAINLY VFR CONDITIONS. A SIGNIFICANT LOW IS EXPECTED TO DEVELOP ON THE FRONT ON WED... AS THE FIRST SYSTEM LIFTS NORTHWARD ACROSS THE CENTRAL LAKES. THE MAIN ISSUE WILL BE WIDESPREAD SHOWERS AND THUNDERSTORMS FOR WED INTO EARLY THU. WHAT COULD EDGE INTO WESTERN AREAS AS A WIDESPREAD STRONG TO SEVERE THUNDERSTORM EVENT LATER ON WED...COULD BECOME MORE OF A LLWS AND HEAVY RAIN ISSUE BY WED NIGHT...EARLY THU. SHOWERS COULD LINGER INTO FRIDAY...AS A COLD TROUGH ALOFT MOVES ACROSS PA. OUTLOOK... TUE...TSRA POSSIBLE...MAINLY W MTNS LATE. WED...WIDESPREAD SHOWERS AND THUNDERSTORMS. THU...MORE SHOWERS AND THUNDERSTORMS WITH THE COLD FRONT. GUSTY WINDS AS WELL. FRI...GUSTY WINDS...ALSO SHOWERS...ESPECIALLY ACROSS THE WEST. && .CLIMATE... HARRISBURG RAINFALL TO DATE IS 7.45". THIS MAKES IT THE SECOND WETTEST APRIL ON RECORD...SECOND ONLY TO 1983 WHEN 7.96" OF RAIN FELL. WITH SEVERAL DAYS YET TO GO IN THE MONTH...WE STILL HAVE SEVERAL CHANCES AT ADDITIONAL PRECIPITATION AND A POSSIBLE SHOT AT THE RECORD. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...MARTIN CLIMATE...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 254 PM EDT MON APR 25 2011 PAZ004>006-010>012-017>019-024>028-033-034-037-041-042-045-046- 049>053-261900- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-CLEARFIELD- NORTHERN CENTRE-SOUTHERN CENTRE-CAMBRIA-BLAIR-HUNTINGDON-MIFFLIN- JUNIATA-SOMERSET-BEDFORD-TIOGA-NORTHERN LYCOMING-SULLIVAN- SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION-SNYDER-MONTOUR- NORTHUMBERLAND-COLUMBIA- 254 PM EDT MON APR 25 2011 ...SEVERE THUNDERSTORM WATCH 202 IN EFFECT UNTIL 10 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE IS A SLIGHT RISK OF MORE STRONG TO SEVERE STORMS ON TUESDAY AND WEDNESDAY. THIS IS ESPECIALLY THE CASE FOR LATER WEDNESDAY...AS A STORM SYSTEM LIFTS NORTHWARD ACROSS THE OHIO VALLEY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL LIKELY BE NEEDED. PAZ035-036-056>059-063-261900- FULTON-FRANKLIN-PERRY-DAUPHIN-SCHUYLKILL-LEBANON-CUMBERLAND- 254 PM EDT MON APR 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO THE EVENING. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE IS A SLIGHT RISK OF MORE STRONG TO SEVERE STORMS ON TUESDAY AND WEDNESDAY. THIS IS ESPECIALLY THE CASE FOR LATER WEDNESDAY...AS A STORM SYSTEM LIFTS NORTHWARD ACROSS THE OHIO VALLEY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE BE NEEDED. PAZ064>066-261900- ADAMS-YORK-LANCASTER- 254 PM EDT MON APR 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. THERE IS A SLIGHT RISK OF MORE STRONG TO SEVERE STORMS ON TUESDAY AND WEDNESDAY. THIS IS ESPECIALLY THE CASE FOR LATER WEDNESDAY...AS A STORM SYSTEM LIFTS NORTHWARD ACROSS THE OHIO VALLEY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MS
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
245 PM EDT MON APR 25 2011
PAZ010-017-251945-
CLEARFIELD PA-ELK PA-
245 PM EDT MON APR 25 2011
...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN CLEARFIELD AND
SOUTHERN ELK COUNTIES...
AT 240 PM EDT...A STRONG THUNDERSTORM WAS NEAR HAWTHORN...MOVING
NORTHEAST AT 35 MPH.
WIND GUSTS TO 50 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.
THIS STORM WILL BE NEAR DUBOIS AROUND 320 PM...BROCKPORT
AROUND 330 PM...FORCE AROUND 340 PM AND MEDIX RUN AROUND 350 PM.
THIS WILL IMPACT I-80 BETWEEN MILE MARKERS 97 AND 110.
THIS WILL ALSO IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 119...ROUTE
219...ROUTE 322...STATE ROAD 120...STATE ROAD 153...STATE ROAD 255.
LAT...LON 4116 7829 4104 7880 4115 7880 4120 7878
4121 7876 4120 7872 4122 7872 4123 7874
4126 7874 4130 7884 4132 7886 4148 7853
FORECASTER: RXRThe State College radar (KCCX), 59 km away, was scanning. The volume nearest the first event began at 19:34 UTC.
6 hail. Local standard time, as filed.
Half-dollar to slightly less than golf-ball size hail (1.25-1.50 inch diameter) splattered like large, wet snow balls when they hit the ground.
Quarter size hail (1.00 inch) reported at Valley Farmer's Market on Bennetts Valley Highway in Weedville.
Golf ball (1.75 inch) hail reported at the Driftwood Post Office.
Spotter reported quarter size hail (1 inch diameter) driving west from Kane to Ludlow.
Nickel (0.88 inch) hail report from Roaring Branch in extreme northeast Lycoming County. This was a web report relayed through spotternetwork.org.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2011Every state in 2011This day in weather historyWarnings in Pennsylvania, April 2011
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 286281, 286282, 286283, 286284, 289712, 286285.