A fast-moving squall line moved quickly east across northern Pennsylvania from the late evening hours through just after midnight on 25 May 2011. The line of severe thunderstorms produced isolated wind damage as it raced through the northern mountains.
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.
A fast-moving squall line moved quickly east across northern Pennsylvania from the late evening hours through just after midnight on 25 May 2011. The line of severe thunderstorms produced isolated wind damage as it raced through the northern mountains.
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 May 25, 7:07 PM EST, 1 hour 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 807 PM EDT WED MAY 25 2011 .SYNOPSIS... A WEAKENING UPPER-LEVEL TROUGH WILL AFFECT OUR REGION THURSDAY WITH AN INCREASED CHANCE OF THUNDERSTORMS. THE FLOW ABOUT THE MASSIVE RIDGE OVER THE WESTERN ATLANTIC WILL KEEP THE CHANCE OF THUNDER IN THE FORECAST INTO SATURDAY. THE RIDGE RETROGRADES OVER THE EASTERN UNITED STATES AND A MASSIVE UPPER HIGH MOVES OVER THE REGION. A 5940M HIGH DEVELOPS LATER IN THE WEEKEND. THE FIRST HEAT EPISODE OF THE SUMMER COULD BEGIN LATER THIS MEMORIAL WEEKEND AND INTO NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... SHALLOW AND RELATIVELY HIGH-BASED...FAIR WEATHER CU HAVE DISSIPATED...LEAVING GENERALLY CLEAR SKIES ACROSS PRACTICALLY THE ENTIRE CWA EARLY THIS EVENING. LINE OF STRONG TO SEVERE TSRA HAS BOWED OUT/ACCELERATED ACROSS FAR NERN OHIO DURING THE PAST HOUR...AND WILL TRACK EAST AT 30-35 MPH REACHING EXTREME WESTERN WARREN COUNTY RIGHT AROUND 02Z. INCREASING 925-850 MB THETA-E ADVECTION AHEAD OF THIS LINE SHOULD MAINTAIN ITS INTENSITY THROUGH ABOUT 03Z BEFORE THE TSRA GRADUALLY WEAKEN IN THE COOLER/MORE STABLE BOUNDARY LAYER NEAR AND TO THE EAST OF KBFD AND KDUJ. INCREASED CHCS FOR CONVECTION RIGHT UP TO AROUND 100 PERCENT IN THE 03-06Z TIME-FRAME ACROSS THE NW ZONES...THEN MAINTAINED THE PREVIOUS SHIFT'S THINKING OF MAINLY SCTD SHOWERS/TSRA THROUGH THE LATE NIGHT HOURS. SPC'S LATEST TORNADO WATCH 372 VALID UNTIL 01Z HAS BEEN EXTENDED EAST TO INCLUDE EXTREME NWRN PENN - ERIE AND CRAWFORD COUNTIES. A FEW STRONG TO SEVERE TSRA EMBEDDED IN THIS LINE COULD BLEED OVER THE WATCH AREA AND INTO WARREN/MCKEAN COUNTIES BETWEEN 02-03Z. SKIES SHOULD STAY CLEAR EARLY TONIGHT ACROSS THE SE HALF OF THE CWA...FOLLOWED BY INCREASING CLOUDS WITH A CHANCE FOR A FEW SHOWERS/TSRA MAINLY TO THE NORTH OF A LINE FROM KJST...TO KAOO AND KSEG. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... THE PLUME OF DEEPER MOISTURE MOVES OVER OUR REGION TOMORROW. WE ARE FORECAST TO HAVE STRONG SOUTH-SOUTHWEST WINDS AND CAPE IN THE 1200 TO 1800 JKG-1 RANGE. THERE SHOULD BE SOME THUNDERSTORMS DEVELOPING ON THURSDAY. GUIDANCE AND ENSEMBLES IMPLY GOOD CHANCE OF SHOWERS AND THUNDERSTORMS THURSDAY MOVING WEST TO EAST BY MID AFTERNOON INTO THE EVENING HOURS. THE SREF POPS ARE NOT VERY HIGH AND ROLLED BACK POPS A BIT IN EASTERN AREAS. STILL...IT SHOULD BE A FAIRLY WARM AND HUMID DAY WITH BETTER SOUTHERLY FLOW. WILL HAVE TO MONITOR EVOLUTION AND POTENTIAL FOR SEVERE WEATHER ON THURSDAY AFTERNOON. SPC HAS MOST OF CENTRAL AND WESTERN PA IN SLIGHT RISK ON THURSDAY. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... BY SATURDAY DEEPEST TROF BACK TOWARDS THE PAC NW WITH LONG SW FETCH ALL THE WAY TOWARDS GREAT LAKES WITH SE RIDGING. THIS WILL KEEP THE AREA IN A MILD TEMPERATURE PATTERN AND ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. BIG CHANGES BEGIN ON SUNDAY AS PAC NW TROUGH MOVES E AND DEEPENS OVER ROCKIES AND A STRONG RIDGE DEVELOPS OVER THE OHIO VALLEY. THIS WILL BRING A SEVERAL DAY BREAK IN THE PRECIPITATION AND A REAL TASTE OF SUMMER TIME TEMPERATURES NEXT WEEK. SOME INDICATION THAT RIDGE WILL RETROGRADE MIDDLE OF NEXT WEEK /TO THE MORE CLIMO FAVORED SW/ AS A COOLER AND DRIER NW FLOW SETTLES IN. IN ANY CASE A WELCOME DRYING TREND IS ON THE HORIZON. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... VFR CONDITIONS PREVAIL ACROSS CWA EARLY THIS EVENING. MAIN CONCERN FOR EARLY PORTION OF TAF PERIOD IS APPROACHING LINE OF STRONG TO SEVERE TSRA ACROSS FAR NERN OHIO. THESE WILL MAINTAIN THEIR STRENGTH FOR A COUPLE MORE HOURS AS THEY TRACK EAST AT 30-35 MPH...BUT SHOULD BE GRADUALLY WEAKENING AS THEY APPROACH KBFD/KDUJ BETWEEN 02Z-04Z. OTHERWISE...EXPECT SOME AREAS OF MVFR HAZE AND GROUND FOG TO DEVELOP /WITH A FEW PLACES DIPPING TO IFR FOR A SHORT TIME/ OVERNIGHT. THESE WILL BURN OFF SHORTLY AFTER SUNRISE THURSDAY. THUNDERSTORM RISK INCREASES FOR THURSDAY AFTERNOON...WITH SCATTERED CONVECTION DEVELOPING. BUT MAINLY VFR FLYING RULES DURING THE DAY...OUTSIDE OF ANY THUNDERSTORMS. OUTLOOK... THUR...LOW CIGS PSBL CNTRL/EAST EARLY IN FOG/HAZE. SCT TSRA AFT 19Z. FRI-SAT...AM FOG AREAS MVFR/IFR. ISOLD AFTERNOON TSRA. SUN-MON...NO SIG WX. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && SYNOPSIS...GRUMM/LAMBERT NEAR TERM...LAMBERT SHORT TERM...GRUMM LONG TERM...GARTNER AVIATION...GRUMM/RXR
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 858 PM EDT WED MAY 25 2011 PAZ004-005-010-261200- WARREN-MCKEAN-ELK- 858 PM EDT WED MAY 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EARLY TONIGHT AS A LINE OF STORMS RACES EAST FROM ERIE AND CRAWFORD COUNTIES. A GRADUAL DECREASE IN STORM SEVERITY CAN BE EXPECTED AS THEY MOVE EAST OF A LINE FROM BRADFORD TO KANE AFTER 11 PM. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ON THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND AGAIN THURSDAY AFTERNOON. PAZ006-011-012-017-018-024-025-033-034-261200- POTTER-CAMERON-NORTHERN CLINTON-CLEARFIELD-NORTHERN CENTRE-CAMBRIA- BLAIR-SOMERSET-BEDFORD- 858 PM EDT WED MAY 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW...AS A LINE OF STRONG TO SEVERE THUNDERSTORMS ACROSS FAR NORTHWESTERN PENNSYLVANIA MOVES SOUTHEAST AND WEAKENS OVERNIGHT. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS ON THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THURSDAY AFTERNOON. PAZ019-026>028-035>037-041-042-045-046-049>053-056>059-063>066- 261200- SOUTHERN CENTRE-HUNTINGDON-MIFFLIN-JUNIATA-FULTON-FRANKLIN-TIOGA- NORTHERN LYCOMING-SULLIVAN-SOUTHERN CLINTON-SOUTHERN LYCOMING-UNION- SNYDER-MONTOUR-NORTHUMBERLAND-COLUMBIA-PERRY-DAUPHIN-SCHUYLKILL- LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER- 858 PM EDT WED MAY 25 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THIS IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ON THURSDAY AND FRIDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THURSDAY AFTERNOON AND AGAIN ON FRIDAY. LAMBERT
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
810 PM EDT WED MAY 25 2011
PAZ004-260200-
WARREN PA-
810 PM EDT WED MAY 25 2011
...A LINE OF STRONG TO POSSIBLY SEVERE THUNDERSTORMS NEAR THE
PENNSYLVANIA...OHIO STATE LINE WILL AFFECT WESTERN WARREN COUNTY
BETWEEN 920 PM AND 10 PM EDT...
AT 801 PM EDT...A LINE OF STRONG THUNDERSTORMS WAS LOCATED ACROSS
EXTREME NORTHEASTERN OHIO...JUST TO THE WEST OF CONNEAUT AND ANDOVER
OHIO. THE LINE OF THUNDERSTORMS WAS MOVING RAPIDLY TO THE EAST AT 45
MPH.
WIND GUSTS BETWEEN 50 AND 55 MPH...AND PEA TO PENNY SIZE HAIL ARE
POSSIBLE WITH THESE STORMS. THESE STORMS WILL BE NEAR SPRING CREEK
AROUND 930 PM...SUGAR GROVE AROUND 945 PM AND RUSSELL AROUND 1000 PM.
THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 6...ROUTE 62.
LAT...LON 4200 7905 4196 7906 4176 7932 4162 7946
4162 7961 4163 7962 4197 7962 4200 7961
FORECASTER: LAMBERTThe Buffalo radar (KBUF), 135 km away, was scanning. The volume nearest the first event began at 01:46 UTC.
6 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds estimated near 60 mph knocked down numerous trees in Spring Creek.
Thunderstorm winds estimated near 60 mph knocked down numerous trees and utility wires in and around the Bradford area.
Thunderstorm winds estimated near 70 mph knocked down hundreds of trees along Kansas Branch Road from the New York border south to near Duke Center. A few homes also sustained minor roof damage.
Thunderstorm winds estimated near 60 mph knocked down numerous trees and utility wires along PA 872 near Austin.
Thunderstorm winds estimated near 60 mph knocked down trees along PA 46 just west of Emporium.
Thunderstorm winds estimated near 60 mph knocked down trees along Hyner Mountain Road between PA 120 and PA 46.
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, May 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: 296739, 296734, 296735, 296737, 296736, 296738.