Isolated severe thunderstorms developed across western Pennsylvania and eastern Ohio ahead of a cold front.
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 PBZ wrote it up.
Isolated severe thunderstorms developed across western Pennsylvania and eastern Ohio ahead of a cold front.
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 Pittsburgh, PA wrote its last area forecast discussion before the first event at Jul 21, 1:06 PM EST, 3 hours 44 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 206 PM EDT WED JUL 21 2010 .SYNOPSIS... SCATTERED THUNDERSTORMS CAN BE EXPECTED THROUGH THIS EVENING AS A COLD FRONT CROSSES THE UPPER OHIO VALLEY. HIGH PRESSURE WILL BRING DRY AND WARM WEATHER FOR THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... COLD FRONT WAS ANALYZED FROM OVER LAKE ERIE TO JUST SOUTH OF CHICAGO AS OF 18Z, WITH MID/UPPER JET STREAK DIGGING INTO THE BASE OF GREAT LAKES TROUGH. SCATTERED THUNDERSTORM DEVELOPMENT IS STILL EXPECTED LATE THIS AFTERNOON AND THIS EVENING BETWEEN ONGOING CLUSTERS TO THE NORTH OF I 80 AND TO THE NORTH OF CHARLESTON. GIVEN RAPID FLOW ALOFT AND MODERATE INSTABILITY IN PLACE OVER THE UPPER OHIO VALLEY, SLIGHT RISK OF SEVERE STORMS WILL PERSIST THROUGH THE EVENING...MODERATE RISK WAS FORECAST NEAR AND EAST OF DUBOIS. PRIMARY SEVERE THREAT WILL COME FROM DAMAGING WIND...AND SOME HAIL EARLY AS BOUNDARY LAYER WIND HAS VEERED TO THE SOUTHWEST AND WEST. SEVERE THREAT, AND THUNDERSTORM POTENTIAL WILL DIMINISH RAPIDLY BY, OR SHORTLY AFTER SUNSET AS COLD FRONT MOVES OVER THE AREA AND AS LOSS OF HEATING SAPS INSTABILITY. OVERNIGHT LOW ARE FORECAST NEAR GUIDANCE AND SHOULD BE NEAR, OR SLIGHTLY ABOVE THE SEASONAL AVERAGES. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... HIGH PRESSURE WILL BUILD ACROSS THE REGION ON THURSDAY...BUT A SMALL CHANCE FOR SHOWERS AND THUNDERSTORMS IS BACK IN THE FORECAST BY THURSDAY NIGHT FOR WESTERN AND NORTHERN ZONES, AND ALL OTHER COUNTIES ON FRIDAY AS A WARM FRONT LIFTS ACROSS THE UPPER OHIO IN ADVANCE OF LOW PRESSURE CROSSING THE WESTERN GREAT LAKES. STRONG WARM ADVECTION INTO THE MID LEVELS IS EXPECTED TO PROVIDE THE LIMITING FACTOR...THUS POP NUMBERS WERE CONFINED TO THE SLIGHT CHANCE /BARELY-CHANCE CATEGORY FOR NOW...ANY STORMS THAT DO FORM HAVE A SLIGHT RISK OF BECOMING SEVERE. MID/UPPER TROUGH/SURFACE COLD IS PROJECTED OVER THE WESTERN GREAT LAKES BY SATURDAY...THUS PRECIPITATION PROBABILITIES WERE INCREASED TO BETTER CHANCE NUMBERS ALL ZONES. SHORT TERM TEMPERATURES WERE GENERALLY FORECAST ABOUT 5 TO 10 DEGREES ABOVE NORMAL GIVEN PROGS OF RISING HEIGHTS/FLAT RIDGING AND WARM ADVECTION. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... WHILE YESTERDAYS MODELS WERE INDICATING A SLOWER COLD FRONT PASSAGE THAT WOULD TAKE MOST OF THE WEEKEND...00Z MODELS INDICATE THAT THE PASSAGE SHOULD TAKE PLACE MORE QUICKLY. 00Z GFS/ECMWF BOTH SHOW THE FRONT APPROACHING THE CWA FROM THE WEST SATURDAY NIGHT AND DEPARTING SUNDAY AFTERNOON. HAVE CHANGED POPS ACCORDINGLY. AFTER THE COLD FRONT MOVES THROUGH...HIGH PRESSURE IS EXPECTED TO STRETCH ACROSS THE GREAT LAKES FOR THE BEGINNING OF THE WORK WEEK. CONDITIONS SHOULD REMAIN DRY...WITH THE TEMPERATURES GOING UP 2-3 DEGREES EACH DAY. ALTHOUGH A COLD FRONT WILL BEGIN TO DROP ACROSS THE GREAT LAKES ON WEDNESDAY...IT SHOULD REMAIN WEST OF THE FORECAST AREA THAT DAY. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON WITH A COLD FRONT. STILL NOT ENOUGH CONFIDENCE IN ANY PARTICULAR LOCATION TO INCLUDE TS IN THE TAFS AT THIS TIME...AND WILL CONTINUE CB MENTION INSTEAD. CHANCES FOR FOG OVERNIGHT WILL LIKELY DEPEND ON WHERE HEAVIER RAINFALL TAKES PLACE THIS AFTERNOON...AND WILL ALLOW THE EVENING SHIFT TO EVALUATE FOG DEVELOPMENT. FOR NOW...WILL CONTINUE MENTION OF MVFR VISIBILITIES. HIGH PRESSURE RIDGE WILL THEN ALLOW FOR VFR CONDITIONS ON THURSDAY. UNSETTLED PATTERN WILL BEGIN TO DEVELOP ON FRIDAY...WITH RESTRICTIONS POSSIBLE IN SHOWERS AND THUNDERSTORMS FROM FRIDAY THROUGH SUNDAY AFTERNOON. HIGH PRESSURE WILL THEN RETURN SUNDAY NIGHT AND BRING VFR CONDITIONS FOR MONDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && 15/33
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 256 PM EDT WED JUL 21 2010 OHZ039>041-048>050-PAZ007>009-013>016-020>023-029-030-WVZ001>003- 221900- TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-JEFFERSON OH-MERCER- VENANGO-FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY- ARMSTRONG-INDIANA-WASHINGTON-WESTMORELAND-HANCOCK-BROOKE-OHIO- 256 PM EDT WED JUL 21 2010 ...SEVERE THUNDERSTORM WATCH 509 IN EFFECT UNTIL 9 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA AND NORTHERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. SEVERE THUNDERSTORM WATCH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE WILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS ON FRIDAY WITH THE PRIMARY SEVERE THREAT COMING FROM DAMAGING THUNDERSTORM WIND. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. OHZ058-059-PAZ031-032-WVZ004-221900- GUERNSEY-BELMONT-GREENE-FAYETTE-MARSHALL- 256 PM EDT WED JUL 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL OHIO...SOUTHWEST PENNSYLVANIA AND NORTHERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE WILL BE A SLIGHT RISK OF SEVERE THUNDERSTORMS ON FRIDAY WITH THE PRIMARY SEVERE THREAT COMING FROM DAMAGING THUNDERSTORM WIND. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MDZ001-OHZ057-068-069-WVZ012-021>023-041-221900- GARRETT-MUSKINGUM-NOBLE-MONROE-WETZEL-MARION-MONONGALIA-PRESTON- TUCKER- 256 PM EDT WED JUL 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST CENTRAL OHIO AND NORTHERN WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
232 PM EDT WED JUL 21 2010
PAZ009-211930-
FOREST PA-
232 PM EDT WED JUL 21 2010
...HEAVY RAIN...
THUNDERSTORMS WITH HEAVY RAIN TO MOVE THROUGH THE FOLLOWING COUNTY...
FOREST...
AT 228 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH
SHOWED THUNDERSTORMS WITH HEAVY RAIN 2 MILES EAST OF NEILLTOWN...OR
ABOUT 4 MILES NORTHWEST OF WEST HICKORY...MOVING EAST AT 30 MPH.
THESE THUNDERSTORMS CAN PRODUCE HEAVY RAIN THAT MAY CAUSE PONDED
WATER ON ROADS AND IN LOW LYING AREAS. VISIBILITY CAN BE REDUCED. IN
ADDITION...WIND GUSTS UP TO 50 MPH ARE POSSIBLE WITH THIS STORM.
SOME LOCATIONS THAT WILL BE IMPACTED BY THESE THUNDERSTORMS
INCLUDE...
WEST HICKORY... KELLETTVILLE... BALLTOWN...
MARIENVILLE... LYNCH...
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.
PLEASE REPORT HEAVY RAIN AND FLOODING PROBLEMS TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.
LAT...LON 4162 7895 4144 7895 4143 7898 4144 7899
4144 7906 4142 7907 4140 7910 4152 7952
4163 7952 4163 7903SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
540 PM EDT WED JUL 21 2010
PAZ013-014-020-212245-
BEAVER PA-BUTLER PA-LAWRENCE PA-
540 PM EDT WED JUL 21 2010
...HEAVY RAIN...
THUNDERSTORM WITH HEAVY RAIN AND HAIL MOVING THROUGH SOUTHERN
LAWRENCE COUNTY TOWARD NORTHERN BEAVER AND SOUTHERN BUTLER COUNTY...
AT 532 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH
SHOWED THUNDERSTORMS WITH HEAVY RAIN 4 MILES NORTH OF ELLWOOD CITY...
MOVING SOUTHEAST AT 30 MPH.
THESE THUNDERSTORMS CAN PRODUCE HEAVY RAIN THAT MAY CAUSE PONDED
WATER ON ROADS AND IN LOW LYING AREAS. VISIBILITY CAN BE REDUCED. IN
ADDITION TO HEAVY RAIN...HAIL AND WIND GUSTS IN EXCESS OF 40 MPH ARE
ALSO POSSIBLE.
SOME LOCATIONS THAT WILL BE IMPACTED BY THESE THUNDERSTORMS
INCLUDE...
HARLANSBURG... ELLWOOD CITY... MCCONNELLS MILL...
FOMBELL... MORAINE STATE PARK... ZELIENOPLE...
EVANS CITY... MARS... BUTLER...
SAXONBURG... LERNERVILLE... SARVER...
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.
PLEASE REPORT HEAVY RAIN AND FLOODING PROBLEMS TO THE NATIONAL
WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
WEDNESDAY EVENING FOR EAST CENTRAL OHIO AND WESTERN PENNSYLVANIA AND
NORTHERN WEST VIRGINIA.
&&
LAT...LON 4087 7970 4066 7972 4067 7999 4082 8043
4105 8028The Pittsburgh radar (KPBZ), 85 km away, was scanning. The volume nearest the first event began at 21:49 UTC.
2 thunderstorm wind. Local standard time, as filed.
Law enforcement reported large trees down on Citris Road near Malvern.
Law enforcement reported a large tree knocking down power lines at the intersection of SR 171 and SR 9.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2010Every state in 2010This day in weather historyWarnings in Ohio, 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: 248893, 248894.