A strong mid-level disturbance and associated wind flow combined with a moderately unstable air mass to produce numerous severe thunderstorms over north-central Pennsylvania during the early to late evening hours. The background convective environment was favorable for rotating thunderstorms or supercells, and an EF1 tornado was confirmed near Galeton in Potter County.
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 strong mid-level disturbance and associated wind flow combined with a moderately unstable air mass to produce numerous severe thunderstorms over north-central Pennsylvania during the early to late evening hours. The background convective environment was favorable for rotating thunderstorms or supercells, and an EF1 tornado was confirmed near Galeton in Potter County. There were also multiple reports of damaging winds.
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 Jul 24, 2:58 PM EST, 2 hours 12 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 358 PM EDT SAT JUL 24 2010 .SYNOPSIS... A WARM FRONT WILL REMAIN NEAR THE NEW YORK BORDER THROUGH THIS EVENING...THEN SHIFT SOUTHWARD AS A COLD FRONT ON SUNDAY. HIGH PRESSURE WILL BUILD INTO THE REGION EARLY NEXT WEEK...WITH SLIGHTLY COOLER AND DRIER CONDTIONS. TEMPERATURES WILL MODERATE ABOVE NORMAL AGAIN BY MID WEEK WITH A CHC OF SHOWERS. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... NOTHING MUCH NEW...MAIN THING IS SOUTHERN END OF THE BAND OF SHOWERS AND STORMS OVER OH HAVE DIED. REALLY CLEAR BEHIND THIS FEATURE. NASTY STORM NEAR ERIE. VERY WARM AIR AT 850 AND 700 HPA OVER SOUTHERN PA AND MD HAS KEPT IT MOSTLY SUNNY AND HOT. TEMPERATURES ARE NOW WELL INTO THE 90S IN MANY LOCATIONS. IT SHOULD NOT CLEAR OUT WHICH SHOULD LIMIT THE ABILITY TO GO OVER 100F. THOUGH THE 20 TO 22C AIR AT 850 HPA IS NOT FORECAST TO COME OVER THE REGION UNTIL THIS EVENING. COULD BE MANY LATE DAY HIGHS IN THE 96-100F RANGE IN SOUTHERN AREAS. IT IS MOSTLY IN THE MID 80S IN CENTRAL AND NORTHERN MOUNTAINS. CENTRAL AREAS SHOULD TOP OUT IN THE LOWER 90S. TEMPERATURES WILL BE SLOW TO FALL WITH DEW POINTS IN THE LOWER 70S AND A POCKET OF VERY WARM AIR ALOFT GOING BY. THE 20-22C AIR GOES BY OVERNIGHT. WILL BE VERY WARM OVERNIGHT. LOCALLY SOME ISOLATED STORMS HAVE BEGUN TO DEVELOP OVER WESTERN PA. THESE ARE FAR OUT AHEAD OF THE ANTICIPATED SYSTEM TO THE WEST. TO OUR WEST...REMNANT MCS FROM THE MIDWEST FLOODS FRIDAY NIGHT IS TRUCKING...HEADED INTO NORTHWESTERN PA. INTRODUCED THUNDERSTORMS LIKELY WITH THIS SYSTEM AFTER ABOUT 22 UTC. THE PW ANOMALIES AND V-WINDS ARE REALLY SIGNIFICANT WITH THIS SYSTEM. ISOLATED SEVERE IS POSSIBLE...BUT WITH HIGH PW AND MOISTURE FLUX VALUES IN THE 4-5SD ABOVE NORMAL RANGE...THESE STORMS IF THEY DEVELOP COULD PRODUCE LOCALLY HEAVY RAINFALL. PONDERING A FLASH FLOOD WATCH IN NW PA. THUS...EXPECT SHOWERS AND THUNDERSTORMS AFTER ABOUT 2200 UTC AND INCREASING CHANCES THIS EVENING. COULD BE SOME LOCALLY HEAVY RAINFALL IN NW PA BEFORE MIDNIGHT. THE RAIN COULD SPILL INTO CENTRAL AREAS BETWEEN 8 AND 10 PM. SOUTHERN AND SOUTHEASTERN AREAS COULD REMAIN RAIN FREE. && .SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SUNDAY/... THE MCS TO OUR WEST AND THEN THE FRONT PROVIDE EQUAL CONVECTIVE OPPORTUNITY FOR THUNDER. DOUBLE SHOT FOR NW PA AS MCS SHOULD TRIGGER SHOWERS UP THERE. THE FORECAST/GRIDS REFLECT THE HIGH PROBABILITY FORECAST BASED ON A BLEND OF THE SREF/VSREF/HRRR. PUT LIKELY POPS IN THE NW AREAS AS THE MCS AND MODELS WOULD IMPLY A GOOD CHANCE FOR ORGANIZED CONVECTION. WITH HIGH PW AIR COULD BE SOME LOCALLY HEAVY RAINFALL. THE GFS SHOWS VERY HIGH MFLUX VALUES IN NW PA AND INTO NEW YORK IN THE 000O TO 0600 UTC PERIOD. SHOWERS COULD PRODUCE VERY HEAVY RAINFALL UP IN NORTHERN AREAS. THE HRRR AND VSREF SHOW THE CONVECTION WEAKEN AS IT MOVES INTO CENTRAL AND SOUTHERN AREAS. ALL GUIDANCE SHOWS STORMS SAGGING SOUTH. THE PW VALUES DROP FAST IN THE NW SUNDAY FROM LATE MORNING INTO THE EARLY AFTERNOON. THE SOUTHEAST SHOULD GET SOME SHOWERS/THUNDERSTORMS AS THE LARGER SCALE BOUNDARY MOVES THROUGH. NORTHERN AND CENTRAL AREAS COULD GET A SLIGHTLY DRIER AND MORE PLEASANT AFTERNOON AND EVENING. IT MIGHT TAKE UNTIL EVENING FOR THE CONDITIONS TO IMPROVE IN THE EXTREME SOUTHEAST. POPS IN 3-HOUR INCREMENTS SUNDAY IN THE GRIDS TO SHOW THE NW TO SE LOWERING OF POPS WITH THE DRIER...COOLER AIR BEHIND THE FRONTAL SYSTEM. IT SHOULD BE COOLER OVER MOST AREAS TOMORROW...BUT MORE NOTICABLE IN WESTERN AND NORTHERN AREAS. THE COOLER DRIER AIR WILL ARRIVE IN THE SOUTHEAST A BIT LATER SO SOME AREAS WILL BE A BIT COOLER BUT NOT NOTICABLE UNTIL SUNDAY NIGHT INTO MONDAY. MONDAY WILL BE A NEW DAY! && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... THERE COULD BE A LINGERING SHOWER FOR SUNDAY EVENING...BUT LEFT THIS OUT OF THE FCST FOR NOW. COOLER AND DRIER CONDTIONS FOR MONDAY AND TUE. THE HEAT AND HUMIDITY BUILDS BACK FOR WED WITH A CHC OF SHOWERS. LEFT SHOWERS IN FCST INTO EARLY FRIDAY...AS FRONT MAY BE SLOW TO PUSH SOUTH...SHOWERS WERE ALREADY IN FCST...AND IN LINE WITH OTHER OFFICES. 00Z ECMWF DOES NOT SHOW AS MUCH UPPER LEVEL SUPPORT AS THE PREVIOUS RUN. THAT HAS BEEN THE TREND THIS SUMMER. ALSO PUT A SMALL CHC IN FOR LATE SAT...SOME MODEL SPREAD THERE. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS WILL DOMINATE THE ENTIRE REGION UNTIL ABOUT 2200 UTC. SOME GUSTY WINDS ARE POSSIBLE. AFTER 2200 UTC WE ANTICIPATE SHOWERS AND STRONG THUNDERSTORMS TO MOVE INTO NORTHWESTERN PA. THESE STORMS WILL LIKELY PRODUCE MVFR AND PATCHY IFR CONDITIONS LATER THIS EVENING AND OVERNIGHT. SHOWERS SHOULD MAINLY MOVE EAST TO WEST TONIGHT. EXPECT MOSTLY MVFR IN MIST/HAZE. ISOLATED IFR IN RAIN. THUNDERSTORMS WILL BE ABOUT...CHECK CURRENT RADAR BEFORE FLYING. THUNDERSTORMS SUNDAY SHOULD EXIT TO OUR EAST LATER IN THE DAY. THEN DRYING WEATHER. MAINLY VFR IN WEST BY MIDDAY AND VFR/MVFR IN EAST WITH REMAINING STORMS. WE DRY OUT SUNDAY EVENING INTO MONDAY. BUT THE RAIN COULD PRODUCE PATCHY MVFR OVERNIGHT SUNDAY INTO MONDAY. OUTLOOK... SUN...MAINLY VFR...WITH MVFR IN SCT/NUMEROUS AFTN SHRA/TSRA. MON-TUE...MAINLY VFR. WED-THU...MAINLY VFR. SCT AFTN SHRA/TSRA. && .CLIMATE... REC MAX AT MDT TODAY IS 96F...AND FCST IS 98F. STILL BELOW THE RECORD...BUT WE STIL HAVE CHC TO CRACK THAT RECORD. IPT COULD BE CLOSE - RECORD OF 96F IS POSSIBLE IF CONVECTION STAYS AWAY THRU LATE AFTN. && .CTP WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR PAZ019-025>028- 034>036-045-046-049>053-056-058. EXCESSIVE HEAT WARNING UNTIL 9 PM EDT THIS EVENING FOR PAZ057- 059-063>066. && SYNOPSIS...FITZGERALD/MARTIN NEAR TERM...GRUMM/MARTIN SHORT TERM...GRUMM LONG TERM...MARTIN AVIATION...GRUMM CLIMATE...MARTIN
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE STATE COLLEGE PA 448 PM EDT SAT JUL 24 2010 PAZ004>006-010>012-037-041-042-251615- WARREN-MCKEAN-POTTER-ELK-CAMERON-NORTHERN CLINTON-TIOGA- NORTHERN LYCOMING-SULLIVAN- 448 PM EDT SAT JUL 24 2010 ...SEVERE THUNDERSTORM WATCH 530 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...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. A STALLED FRONTAL BOUNDARY NEAR THE NEW YORK BORDER WILL BE THE FOCUS FOR THUNDERSTORMS INTO THIS EVENING. SOME STORMS MAY PRODUCE DAMAGING WIND GUSTS AND HAIL. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTERS SHOULD REPORT STRONG WINDS...HAIL OR WIND DAMAGE. PAZ017-018-024-033-251615- CLEARFIELD-NORTHERN CENTRE-CAMBRIA-SOMERSET- 448 PM EDT SAT JUL 24 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. A STALLED FRONTAL BOUNDARY NEAR THE NEW YORK BORDER WILL BE THE FOCUS FOR THUNDERSTORMS LATER TODAY. A FEW OF THESE STORMS COULD PRODUCE DAMAGING WIND GUSTS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS THE NORTHERN HALF OF THE STATE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. A FEW STORMS MAY BE ON THE STRONG TO SEVERE SIDE ON SUNDAY... AS A COLD FRONT MOVES SOUTHWARD ACROSS THE STATE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. PAZ057-059-063>066-251615- DAUPHIN-LEBANON-CUMBERLAND-ADAMS-YORK-LANCASTER- 448 PM EDT SAT JUL 24 2010 ...EXCESSIVE HEAT WARNING IN EFFECT UNTIL 9 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. EXCESSIVE HEAT WARNING. A STALLED FRONTAL BOUNDARY NEAR THE NEW YORK BORDER WILL BE THE FOCUS FOR THUNDERSTORMS LATER TODAY. A FEW OF THESE STORMS COULD PRODUCE DAMAGING WIND GUSTS AS THEY MOVE INTO THE LOWER SUSQUEHANNA VALLEY THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. A FEW STORMS MAY BE ON THE STRONG TO SEVERE SIDE ON SUNDAY... AS A COLD FRONT MOVES SOUTHWARD ACROSS THE STATE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. PAZ019-025>028-034>036-049>053-056-058-251615- SOUTHERN CENTRE-BLAIR-HUNTINGDON-MIFFLIN-JUNIATA-BEDFORD-FULTON- FRANKLIN-UNION-SNYDER-MONTOUR-NORTHUMBERLAND-COLUMBIA-PERRY- SCHUYLKILL- 448 PM EDT SAT JUL 24 2010 ...HEAT ADVISORY IN EFFECT UNTIL 9 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. HEAT ADVISORY. A STALLED FRONTAL BOUNDARY NEAR THE NEW YORK BORDER WILL BE THE FOCUS FOR THUNDERSTORMS LATER TODAY. A FEW OF THESE STORMS COULD PRODUCE DAMAGING WIND GUSTS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS THE NORTHERN HALF OF THE STATE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. A FEW STORMS MAY BE ON THE STRONG TO SEVERE SIDE ON SUNDAY... AS A COLD FRONT MOVES SOUTHWARD ACROSS THE STATE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. PAZ045-046-251615- SOUTHERN CLINTON-SOUTHERN LYCOMING- 448 PM EDT SAT JUL 24 2010 ...HEAT ADVISORY IN EFFECT UNTIL 9 PM EDT THIS EVENING... ...SEVERE THUNDERSTORM WATCH 530 IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA. .DAY ONE...TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV/STATECOLLEGE ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. HEAT ADVISORY. SEVERE THUNDERSTORM WATCH. A STALLED FRONTAL BOUNDARY NEAR THE NEW YORK BORDER WILL BE THE FOCUS FOR THUNDERSTORMS LATER TODAY. A FEW OF THESE STORMS COULD PRODUCE DAMAGING WIND GUSTS THIS AFTERNOON AND EVENING...ESPECIALLY ACROSS THE NORTHERN HALF OF THE STATE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. A FEW STORMS MAY BE ON THE STRONG TO SEVERE SIDE ON SUNDAY... AS A COLD FRONT MOVES SOUTHWARD ACROSS THE STATE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MARTIN
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE STATE COLLEGE PA 504 PM EDT SAT JUL 24 2010 PAZ004-005-242145- MCKEAN PA-WARREN PA- 504 PM EDT SAT JUL 24 2010 ...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN WARREN AND NORTHWESTERN MCKEAN COUNTIES... AT 501 PM EDT...A STRONG THUNDERSTORM WAS NEAR WARREN...MOVING EAST AT 40 MPH. WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM. PERSONS ACROSS THE REGION SHOULD BE ALERT FOR SUDDEN CHANGES IN STORM STRENGTH. SEEK SHELTER IF THREATENING WEATHER IS OBSERVED OR A WARNING IS ISSUED. THIS STORM WILL BE NEAR SCANDIA AROUND 515 PM...MARSHBURG AROUND 535 PM...LEWIS RUN AROUND 540 PM AND CYCLONE AROUND 545 PM. THIS WILL IMPACT THE FOLLOWING MAJOR ROADS...ROUTE 6...ROUTE 62... ROUTE 219...STATE ROAD 46...STATE ROAD 59...STATE ROAD 446. LAT...LON 4200 7840 4172 7842 4181 7931 4201 7929 FORECASTER: MARTIN
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
600 PM EDT SAT JUL 24 2010
PAZ006-037-242230-
POTTER PA-TIOGA PA-
600 PM EDT SAT JUL 24 2010
...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHEASTERN POTTER AND
WESTERN TIOGA COUNTIES...
AT 553 PM EDT...A LINE OF STRONG THUNDERSTORMS WAS LOCATED FROM 29
MILES SOUTHEAST OF OLEAN TO 21 MILES SOUTHWEST OF WELLSBORO...MOVING
NORTHEAST AT 30 MPH.
WIND GUSTS TO 50 MPH AND PEA SIZE HAIL ARE POSSIBLE WITH THESE
STORMS. DOPPLER RADAR INDICATES THAT THESE STORMS HAVE WEAK ROTATION
IN THEM...WHICH MAY CAUSE THE STORMS TO BECOME STRONGER. THESE
STORMS WILL BE NEAR DENTON HILL STATE PARK AROUND 605 PM...GALETON
AROUND 610 PM...LEONARD HARRISON STATE PARK AROUND 625 PM AND
HARRISON VALLEY AROUND 630 PM.
THIS WILL IMPACT ROUTE 6 FROM COUDERSPORT TO NORTHWEST OF WELLSBORO.
IF THESE STORMS DO GET STRONGER...OR THE ROTATION BECOMES
STRONGER...AN APPROPRIATE TORNADO WARNING OR SEVERE THUNDERSTORM
WARNING WILL BE ISSUED.
LAT...LON 4183 7718 4154 7755 4154 7760 4149 7761
4178 7812 4188 7771 4200 7761 4200 7754
FORECASTER: DANGELOThe Buffalo radar (KBUF), 145 km away, was scanning. The volume nearest the first event began at 22:08 UTC.
14 thunderstorm wind, 2 funnel cloud, 1 hail, 1 tornado. Local standard time, as filed.
Thunderstorm winds estimated near 60 mph knocked down trees along Youngsville Road north of Tidioute.
Thunderstorm winds estimated near 60 mph knocked down trees along Hultburg Road east of Russell.
Thunderstorm winds estimated near 60 mph knocked down trees in Duke Center at the intersection of Oil Valley Road and Main Street.
Thunderstorm winds estimated near 60 mph knocked down trees along Congress Street in Bradford.
Thunderstorm winds estimated near 60 mph knocked down trees along West Coryden Street in Bradford.
Thunderstorm winds estimated near 60 mph knocked down trees and wires along Minard Run Road near Custer City.
Spotter in Galeton reported a rotating wall cloud with a funnel extending from the cloud base.
NWS meteorologists confirmed an EF1 tornado approximately 2 miles west-southwest of Galeton, PA in Potter County. The tornado was on the ground for about 2 minutes and had a path length of just over 1 mile. The estimated maximum wind speed was 90 mph based on tree and utility pole damage indicators. The damage occurred in a very rural area with only minor structural damage to a few cabins. The tornado path was slightly curved and extended from a small tributary on the West Branch of Pine Creek across SR 2002. The EF1 tornado destroyed over 1000 trees and up to 10 utility poles along SR 2002. A pump-house that supplies the town of Galeton with water was impacted by power outages resulting from the downed utility poles.
NWS meteorologists surveyed thunderstorm wind damage in the Blackwell area. They determined that straight-line winds estimated near 60 mph toppled 5-10 utility poles and knocked down numerous trees along SR 414 near the intersection of Wilson Hill Road.
Thunderstorm winds estimated near 60 mph knocked down numerous trees along SR 414 near Cedar Run, making the road impassable.
Thunderstorm winds estimated near 60 mph knocked down trees at Treasure Lake.
A funnel cloud was observed by the public near Treasure Lake.
Thunderstorm winds estimated near 60 mph knocked down trees at the Clinton County Historical Society's Heisey Museum on East Water Street in Lock Haven. Some minor structural damage was also visible.
Thunderstorm winds estimated near 60 mph knocked down trees and power lines at the intersection of Washington Blvd and Cathrine Street. Additional trees and wires were down in other parts of the Williasmport area, but locations were not available.
Thunderstorm winds estimated near 60 mph knocked down trees along SR 287 just north of the intersection of U.S. 220 near Jersey Shore.
Thunderstorm winds estimated near 60 mph knocked down trees in Clearfield Borough.
Thunderstorm winds estimated near 60 mph knocked down a swath of trees in the city of Bloomsburg and Georges Township.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2010Every state in 2010This day in weather historyThe tornado archive for Pennsylvania, 2010Warnings in Pennsylvania, July 2010
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: 238144, 238145, 238147, 238150, 238151, 238149, 238153, 238143, 238187, 238216, 238219, 238226, 244743, 238222, 238240, 238244, 238245, 238247.