A slow moving thunderstorm produced flash flooding across portions of Westmoreland county. Up to 3 inches of rain were reported.
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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 slow moving thunderstorm produced flash flooding across portions of Westmoreland county. Up to 3 inches of rain were reported.
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 May 8, 4:13 PM EST, 2 hours 22 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 513 PM EDT TUE MAY 8 2012 .SYNOPSIS... REMAINING SHOWERS AND THUNDERSTORMS WILL END THIS EVENING AS A COLD FRONT SLIDES EAST OF THE RIDGES. COOLER TEMPERATURES CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... LATE AFTN UPDATE WAS ISSUED TO ADJUST HOURLY TRENDS AND OVERNIGHT LOWS. PREVIOUS... A COLD FRONT WILL PUSH EAST OF THE RIDGES BY THIS EVENING AND BRING A FEW SHOWERS OR THUNDERSTORMS WITH THE FRONTAL PASSAGE. COOLER AND DRIER AIR WILL PUSH INTO THE DISTRICT LATER TONIGHT BEHIND THE FRONT. THE UPPER TROF BEHIND THE FRONT WILL SPAWN SOME SHOWERS WEDNESDAY AFTERNOON WITH THE HEATING OF THE DAY. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/... A FEW RAIN SHOWERS MAY LINGER INTO THE EVENING HOURS OF WEDNESDAY BUT HIGH PRESSURE BUILDING IN LATE WEDNESDAY NIGHT WILL BRING AN END TO THE SHOWERS ALONG WITH CLEARING SKIES MUCH COLDER TEMPERATURES FOR THURSDAY MORNING. HIGH PRESSURE WILL DOMINATE THURSDAY WITH LOTS OF SUNSHINE AND TEMPERATURES REMAINING WELL BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... HIGH PRESSURE WILL DRIFT EAST INTO THE MID ATLANTIC STATES...WITH DRY WEATHER CONTINUING THROUGH LATE SATURDAY. A COLD FRONT IS PROGGED TO MOVE ACROSS THE GREAT LAKES AND INTO THE OHIO VALLEY SUNDAY...BRINGING A CHANCE OF SHOWERS. THE PROGRESS OF THE FRONT SHOULD SLOW EARLY NEXT WEEK AS THE UPPER FLOW BECOMES SOUTHWEST AND A SURFACE WAVE DEVELOPS AND RIDES ALONG THE SURFACE BOUNDARY. UNSETTLED SHOWERY CONDITIONS SHOULD PERSIST MONDAY AND TUESDAY. TEMPERATURES ARE FORECAST TO BE NEAR NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... THE MAIN SWATH OF PRECIPITATION HAS PUSHED EAST OF THE TERMINALS INTO EASTERN PA. THE COLD FRONT HAS REACHED A KFKL...KBVI TO KHLG LINE AND WILL CONTINUE TO ADVANCE SLOWLY EASTWARD THIS EVENING. MVFR CEILINGS AND AREAS OF IFR RESTRICTIONS IN SHOWERS SHOULD IMPROVE TO VFR FOR A FEW HOURS BEHIND THE FRONT EARLY TONIGHT EXCEPT ACROSS THE FAR NORTH. BUFKIT SHOWS A SHALLOW SURFACE BASED INVERSION FORMING AFTER 06Z. EVAPORATION OF MOISTURE FROM RECENT RAIN WOULD TEND TO AID FOG DEVELOPMENT. INCLUDED A PERIOD OF MVFR STRATUS AND FOG LATE TONIGHT FOR ALL TAFS WITH CLOUD BASES LIFTING TO AROUND 3000 WEDNESDAY MORNING. UPPER TROUGH AXIS WILL SWING ACROSS THE UPPER OH VALLEY WEDNESDAY. THERE SHOULD BE INSTABILITY TO ALLOW SCATTERED SHOWERS TO DEVELOP IN THE AFTERNOON. .OUTLOOK...WEDNESDAY NIGHT THROUGH SUNDAY... SURFACE HIGH PRESSURE BUILDING IN FROM THE WEST SHOULD PROVIDE GENERALLY VFR WEATHER WEDNESDAY NIGHT THROUGH SATURDAY. A COLD FRONT WILL MOVE INTO THE REGION AND BRING SCATTERED PRECIPITATION AND THE POTENTIAL FOR RESTRICTIONS SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && 15
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 1229 PM EDT TUE MAY 8 2012 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029-031-073>076-WVZ001>004-012-021>023-041-091630- GARRETT-TUSCARAWAS-CARROLL-COLUMBIANA-COSHOCTON-HARRISON- JEFFERSON OH-MUSKINGUM-GUERNSEY-BELMONT-NOBLE-MONROE-MERCER-VENANGO- FOREST-LAWRENCE-BUTLER-CLARION-JEFFERSON PA-BEAVER-ALLEGHENY- ARMSTRONG-INDIANA-WASHINGTON-GREENE-WESTMORELAND-WESTMORELAND RIDGES- FAYETTE-FAYETTE RIDGES-HANCOCK-BROOKE-OHIO-MARSHALL-WETZEL-MARION- MONONGALIA-PRESTON-TUCKER- 1229 PM EDT TUE MAY 8 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN MARYLAND...EAST CENTRAL OHIO...NORTHWEST PENNSYLVANIA...SOUTHWEST PENNSYLVANIA...WEST CENTRAL PENNSYLVANIA...NORTHERN WEST VIRGINIA AND NORTHERN PANHANDLE OF WEST VIRGINIA. .DAY ONE...THIS AFTERNOON AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. 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.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PITTSBURGH PA
320 PM EDT TUE MAY 08 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 PM TSTM WND DMG HERMITAGE 41.23N 80.44W
05/07/2012 MERCER PA NEWSPAPER
ROOF BLOWN OFF LARGE INDUSTRIAL BUILDING
&&
EVENT NUMBER PBZ1200431
XXSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
647 PM EDT TUE MAY 8 2012
PAZ073-074-082345-
WESTMORELAND PA-WESTMORELAND RIDGES PA-
647 PM EDT TUE MAY 8 2012
...HEAVY RAIN...
SHOWERS AND ISOLATED THUNDERSTORMS WITH HEAVY RAIN WILL CONTINUE TO
MOVE THROUGH THE FOLLOWING COUNTY...WESTMORELAND AND WESTMORELAND
RIDGES...
AT 638 PM EDT NATIONAL WEATHER SERVICE RADAR IN PITTSBURGH INDICATED
A CLUSTER SHOWERS AND ISOLATED THUNDERSTORMS CENTERED 3 MILES
SOUTHWEST OF JEANNETTE...OR ABOUT 3 MILES SOUTHEAST OF
IRWIN...MOVING EAST AT 20 MPH.
THESE SHOWERS AND STORMS ARE MOVING OVER AN AREA THAT HAS ALREADY
RECEIVED A HALF TO THREE QUARTERS OF AN INCH OF RAIN DURING THE
PREVIOUS HOUR. THIS AREA OF RAINFALL WILL POND WATER ON ROADS AND
IN LOW LYING AREAS.
SOME LOCATIONS THAT WILL BE IMPACTED BY THIS CLUSTER OF SHOWERS
INCLUDE...
JEANNETTE... NEW STANTON... GREENSBURG...
LATROBE... DERRY... LIGONIER...
LAUREL MOUNTAIN STATE PARK...
DO NOT DRIVE INTO AREAS WHERE WATER COVERS THE ROAD. THE WATER DEPTH
MAY BE TOO GREAT TO ALLOW SAFE PASSAGE. MOVE TO HIGHER GROUND.
PLEASE REPORT HEAVY RAINFALL AND FLOODING TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.
&&
LAT...LON 4016 7914 4015 7916 4014 7916 4011 7918
4010 7919 4011 7920 4008 7925 4024 7971
4037 7970 4035 7910
15The Pittsburgh radar (KPBZ), 63 km away, was scanning. The volume nearest the first event began at 23:35 UTC.
5 flash flood, 1 heavy rain. Local standard time, as filed.
Emergency management reported heavy rains producing flash flooding across numerous roads and on private properties across the county.
Emergency management reported flooding of church basement in Greensburg.
Emergency management reported a stream flooding homes on 14th Street in Jeannette.
Emergency management reported flooding of a personal care home west of the airport.
Emergency management reported numerous roads flooded in Hempfield Township.
A trained spotter reported 3.00 inches of rain during the event.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2012Every state in 2012This day in weather historyWarnings in Pennsylvania, May 2012
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: 377743, 377746, 377748, 377749, 377750, 377751.