A Surface low pressure system, supported by a strong shortwave aloft, moved from the upper Midwest toward Pennsylvania by the afternoon on the 9th. Breaks in the cloud cover ahead of the associated cold front allowed for the region to destabilize, supporting the development of showers and thunderstorms.
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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.
A Surface low pressure system, supported by a strong shortwave aloft, moved from the upper Midwest toward Pennsylvania by the afternoon on the 9th. Breaks in the cloud cover ahead of the associated cold front allowed for the region to destabilize, supporting the development of showers and thunderstorms. Some of these storms became severe and a small bowing line developed, which brought down trees across southwestern Pennsylvania and northern West Virginia.
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 9, 11:40 AM EST, 1 hour 4 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1240 PM EDT THU JUL 9 2015 .SYNOPSIS... LOW PRESSURE WILL CROSS THE AREA TODAY...PROVIDING WIDESPREAD SHOWERS AND POSSIBLY THUNDERSTORMS. DRY WEATHER RETURNS ON FRIDAY WITH HIGH PRESSURE. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... LOW PRESSURE SYSTEM CONTINUES TO APPROACH THE REGION WITH AN ADVANCING SHORTWAVE ALOFT. STRATUS FROM THIS MORNING ACROSS MOST AREAS FROM PIT AND SOUTH HAS DISSIPATED AND HAS ALLOWED FOR THE LOW LEVELS TO BEGIN MIXING OUT. SUBSTANTIAL DEEP SHEAR...RICH MOISTURE FIELD...AND DESTABILIZATION IN THE AFTERNOON IS EXPECTED TO SUPPORT ORGANIZED THUNDERSTORMS MOSTLY FROM PIT AND SOUTH. THUS...SPC HAS EXPANDED THE SLIGHT RISK FOR SEVERE WEATHER IN THAT REGION. DAMAGING WIND GUSTS ARE THE PRIMARY THREAT AND LOCALIZED FLOODING DUE TO POSSIBLE TRAINING CELLS - AND RECENT RAINFALL - IS ALSO POSSIBLE IF A CONVECTIVE LINE BECOMES MORE ORIENTED TO THE APPROACHING COLD FRONT. THE FRONTAL PASSAGE WILL CAUSE DEW POINTS TO DROP TO MORE COMFORTABLE LEVELS BY LATE TONIGHT AND HIGH PRESSURE BEGINS TO DEVELOP FROM THE WEST TO HELP DIMINISH POPS. && .SHORT TERM /10 PM THIS EVENING THROUGH SUNDAY/... HIGH PRESSURE WILL BE IN PLACE AMID MOSTLY ZONAL FLOW. THIS PATTERN WILL PERSIST LONG ENOUGH TO KEEP FRIDAY AND THE MAJORITY OF THE WEEKEND DRY. A LITTLE MORE SUNSHINE WILL BE APPARENT IN THE PERIOD AS A RESULT OF HIGH PRESSURE. TEMPERATURES AND DEW POINTS WILL BE NEAR AVERAGE AND PROVIDE COMFORTABLE CONDITIONS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... VERY LITTLE CHANGE TO PREVIOUS FORECAST AS FRONTAL BOUNDARY WILL WAVER ACROSS THE REGION THROUGH THE PERIOD...WITH HARD TO TIME SHORTWAVES MOVING EAST IN GENERALLY ZONAL FLOW. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... THUNDERSTORMS EXPECTED THIS AFTERNOON...ESPECIALLY FROM KPIT SOUTH WHERE MORE ORGANIZED STORMS ARE LIKELY DUE TO INCREASED INSTABILITY. WINDS ABOVE THE SURFACE WILL RANGE BETWEEN 45 AND 45KTS ON AVERAGE BUT WITH SFC WINDS GUSTING BETWEEN 25 AND 30KTS LLWS WAS NOT INCLUDED IN THE TAFS. THAT BEING SAID...THERE WILL INEVITABLE BE LULLS IN SURFACE SPEEDS AND DURING THOSE TIMES LLWS WILL LIKELY BE ENCOUNTERED. WS015 24035KT. WINDS WILL BECOME WEST TO NORTHWEST THIS EVENING. .OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE WILL IMPROVE CONDITIONS THURSDAY NIGHT WITH GENERAL VFR EXPECTED INTO THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 1110 AM EDT THU JUL 9 2015 MDZ001-OHZ059-068-069-PAZ021>023-029-031-073>076-WVZ002>004-012- 021>023-041-101515- GARRETT-BELMONT-NOBLE-MONROE-ALLEGHENY-ARMSTRONG-INDIANA-WASHINGTON- GREENE-WESTMORELAND-WESTMORELAND RIDGES-FAYETTE-FAYETTE RIDGES- BROOKE-OHIO-MARSHALL-WETZEL-MARION-MONONGALIA-PRESTON-TUCKER- 1110 AM EDT THU JUL 9 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST CENTRAL OHIO...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA AND NORTHERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. THERE IS A SLIGHT RISK FOR SEVERE WEATHER WITH WIND DAMAGE BEING THE PRIMARY THREAT. LOCALIZED FLOODING IS POSSIBLE WITH TRAINING THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. OHZ039>041-048>050-057-058-PAZ007>009-013>016-020-WVZ001-101515- TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON-JEFFERSON OH- MUSKINGUM-GUERNSEY-MERCER-VENANGO-FOREST-LAWRENCE-BUTLER-CLARION- JEFFERSON PA-BEAVER-HANCOCK- 1110 AM EDT THU JUL 9 2015 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. LOCALIZED FLOODING IS POSSIBLE WITH TRAINING THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The Pittsburgh radar (KPBZ), 73 km away, was scanning. The volume nearest the first event began at 17:42 UTC.
9 thunderstorm wind. Local standard time, as filed.
Local 911 center reported trees down on Township Road in Cumberland Township.
Department of highways reported trees down.
Local 911 center reported a tree down at the intersection of Greenwood Ave and Mahoning Street.
Local 911 reported a large tree down blocking Pechin Road.
Department of highways reported trees down.
Department of highways reported trees down.
Department of highways reported trees down.
Department of highways reported a tree down near routes 201 and 381.
Local 911 center reported trees down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2015Every state in 2015This day in weather historyWarnings in Pennsylvania, July 2015
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: 594602, 594605, 594601, 594600, 594606, 594608, 594607, 594604, 594603.