An isolated severe thunderstorm developed well ahead of an approaching 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.
An isolated severe thunderstorm developed well ahead of an approaching 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 May 27, 1:40 PM EST, 4 hours 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 240 PM EDT WED MAY 27 2009 .SYNOPSIS... SOUTH WINDS AHEAD OF A COLD FRONT WILL CONTINUE TO BRING MOISTURE INTO THE REGION TONIGHT AND THURSDAY. THE FRONT WILL MOVE ACROSS THE AREA LATE THURSDAY. EXPECT WARM AND HUMID CONDITIONS...WITH PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE WEEKEND WITH DRIER AND COOLER AIR. && .NEAR TERM /THROUGH THURSDAY/... COVERAGE OF SHOWERS AND THUNDERSTORMS WILL INCREASE LATE THIS AFTERNOON INTO EARLY EVENING AS BOUNDARY LAYER CONTINUES TO WARM AND HIGHER SURFACE DEW POINTS PUSH EASTWARD ACROSS THE REGION. EXPECT COVERAGE TO DIMINISH SOMEWHAT BY LATE THIS EVENING WITH LOSS OF SOLAR HEATING...THEN INCREASE AGAIN BY MIDDAY THURSDAY AS FRONT DRAWS CLOSER. STILL PLAN TO REDUCE LIKELY POPS TO SCATTERED LATE TONIGHT AND THURSDAY MORNING AND THEN BUMP UP BACK UP TO LIKELY FOR THE AFTERNOON. OVERNIGHT LOWS WILL HOLD IN THE LOWER TO MID 60S. TEMPERATURES SHOULD CLIMB INTO MID 70S FAR NORTH AND LOWER AND MID 80S SOUTH THURSDAY AFTERNOON. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... SHOWERS WILL DIMINISH BY LATE THURSDAY NIGHT AS THE FRONT EXITS TO THE EAST...WITH SCATTERED SHOWERS LINGERING INTO FRIDAY MORNING ALONG THE RIDGES. HIGH PRESSURE WILL BUILD INTO THE AREA FRIDAY...BRINGING DRIER AND COOLER CONDITIONS. GFS STILL HINTS AT A SHORT WAVE AND ASSOCIATED SURFACE TROUGH PUSHING ACROSS THE REGION LATE SATURDAY. WILL KEEP SLIGHT CHANCE POPS FOR SHOWERS SATURDAY PER CURRENT FORECAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... GFS ENSEMBLE INDICATES COOLER NORTHWEST FLOW ALOFT THROUGH THIS LONG TERM PORTION OF THE FORECAST WITH SCATTERED SHOWERS AND THUNDERSHOWERS. TEMPERATURES WILL AVERAGE JUST SLIGHTLY BELOW NORMAL. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... SCT MVFR/IFR FLGT CONDS IN SHRA/TSRA INTO THE EVENING HOURS...OTHERWISE GENERALLY VFR FLGT CONDS THROUGH THE OVERNIGHT. SCT MVFR VSBYS IN BR AROUND SUNRISE. INSTABILITY HAS INCREASED WITH HEATING OF THE DAY. CONVECTION WILL CONT INTO THE EVENING HOURS. ACTIVITY WILL DIMINISH AFTER SUNSET. SFC WNDS S 5-12KTS...HIGHER GUSTS IN/NEAR CONVECTION. LOWER FLGT CONDS IN SCT CONVECTION CONTINUING THURSDAY AND THURSDAY EVENING AS A COLD FRONT APPROACHES FROM THE WEST. THE COLD FRONT WILL CROSS THE FORECAST AREA THURSDAY EVENING/NIGHT WITH A ROUND OF SHOWERS AND STORMS EXPECTED IN ADVANCE OF FROPA. MAINLY VFR FLGT CONDS THIS WEEKEND THRU MONDAY WITH SCT INSTABILITY SHOWERS/ISOL TSTMS IN COLDER NW FLOW. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 311 AM EDT WED MAY 27 2009 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029>032-WVZ001>004-012-021>023-041-281000- 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-WESTMORELAND-GREENE-FAYETTE-HANCOCK- BROOKE-OHIO-MARSHALL-WETZEL-MARION-MONONGALIA-PRESTON-TUCKER- 311 AM EDT WED MAY 27 2009 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...TODAY 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 505 PM EDT WED MAY 27 2009 PAZ014-021-022-030-272200- ALLEGHENY PA-ARMSTRONG PA-BUTLER PA-WESTMORELAND PA- 505 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... ARMSTRONG...ALLEGHENY...WESTMORELAND AND BUTLER... AT 503 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A CLUSTER OF THUNDERSTORMS NEAR FREEPORT...MOVING NORTHEAST AT 10 TO 15 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... NEW KENSINGTON... NATRONA HEIGHTS... LERNERVILLE... SARVER... FREEPORT... APOLLO... VANDERGRIFT... CROOKED CREEK LAKE PARK... FORD CITY... KITTANNING... ELDERTON... THIS CLUSTER OF STORMS WILL PRODUCE RAINFALL AT THE RATE OF TWO INCHES PER HOUR. HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND CREEKS MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. && 15
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 518 PM EDT WED MAY 27 2009 MDZ001-PAZ032-WVZ023-272215- FAYETTE PA-GARRETT MD-PRESTON WV- 518 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... GARRETT...FAYETTE AND PRESTON... AT 516 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A SMALL CLUSTER OF THUNDERSTORMS 3 MILES NORTH OF HAZELTON...MOVING NORTHEAST AT 5 TO 10 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... HAZELTON... MARKLEYSBURG... THESE STORMS ARE PRODUCING RAINFALL AT THE RATE OF ONE TO TWO INCHES PER HOUR AND ARE MOVING OVER AREAS WHERE RAIN HAS ALREADY FALLEN. THIS INCLUDES THE PINEY RUN BASIN. THIS HEAVY RAIN MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND CREEKS MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. && 15
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 523 PM EDT WED MAY 27 2009 PAZ007-008-272215- MERCER PA-VENANGO PA- 523 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... VENANGO AND MERCER... AT 520 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A CLUSTER OF THUNDERSTORMS 6 MILES NORTHWEST OF FREDONIA...MOVING NORTHEAST AT 15 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... FREDONIA... MAURICE K GODDARD STATE PARK... THESE STORMS WILL PRODUCE RAINFALL AT THE RATE OF AT LEAST TWO INCHES PER HOUR AND MAY GENERATE SOME SMALL HAIL UP TO THE SIZE OF DIMES. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...STRONG WINDS OR WIND DAMAGE TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. 15
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 528 PM EDT WED MAY 27 2009 MDZ001-WVZ023-041-272230- GARRETT MD-PRESTON WV-TUCKER WV- 528 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... GARRETT...TUCKER AND PRESTON... AT 525 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A CLUSTER OF THUNDERSTORMS CENTERED NEAR SILVER LAKE...MOVING NORTHEAST AT 5 TO 10 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... KEMPTON... SILVER LAKE... CATHEDRAL STATE PARK... GORMAN... REDHOUSE... THESE STORMS ARE PRODUCING RAINFALL AT THE RATE OF ONE TO TWO INCHES PER HOUR AND ARE MOVING OVER AREAS WHERE RAIN HAS ALREADY FALLEN. THIS INCLUDES THE STEMPLE RIDGE AREA...MAPLE RUN BASIN...AS WELL AS THE LAUREL RUN BASIN IN SOUTHERN GARRETT COUNTY. THIS HEAVY RAIN MAY FLOOD LOW LYING AREAS SUCH AS DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED ROADS AS THEY MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND CREEKS MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY FLOOD WATERS. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL OR HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. && 15
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 536 PM EDT WED MAY 27 2009 PAZ021>023-030-272230- ALLEGHENY PA-ARMSTRONG PA-INDIANA PA-WESTMORELAND PA- 536 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTIES... ARMSTRONG...ALLEGHENY...WESTMORELAND AND INDIANA... AT 534 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A SMALL CLUSTER OF THUNDERSTORMS NEAR MCKEESPORT...MOVING NORTHEAST AT 15 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... MCKEESPORT... JEFFERSON BORO... ELIZABETH BORO... BALDWIN... WEST MIFFLIN... WILKINSBURG... TURTLE CREEK... IRWIN... MONROEVILLE... PENN HILLS... MURRYSVILLE... PLUM... THESE STORMS MAY PRODUCE RAINFALL AT THE RATE OF TWO INCHES PER HOUR AND MAY GENERATE SOME SMALL HAIL. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL...OR HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. 15
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE PITTSBURGH PA 642 PM EDT WED MAY 27 2009 PAZ007-272345- MERCER PA- 642 PM EDT WED MAY 27 2009 ...THUNDERSTORMS... THUNDERSTORMS TO MOVE THROUGH THE FOLLOWING COUNTY... MERCER... AT 640 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR IN PITTSBURGH INDICATED A STRONG THUNDERSTORMS 3 MILES WEST OF MAYSVILLE...OR ABOUT 12 MILES NORTH OF SHARON...MOVING EAST AT 15 MPH. SOME LOCATIONS THAT WILL BE IMPACTED BY THESE STORMS INCLUDE... MAYSVILLE... SHENANGO... JAMESTOWN... DONNER CROSSROADS... HENLEIN... OSGOOD... K O JUNCTION... LEECHS CORNERS... SALEM... KENNARD... OSBORN... PETERSBURG... THIS STORM WILL GENERATE RAINFALL AT THE RATE OF AT LEAST TWO INCHES PER HOUR AND MAY PRODUCE SOME SMALL HAIL UP TO THE SIZE OF DIMES. MOVE TO A SAFE PLACE IF THUNDERSTORMS APPROACH. PLEASE REPORT HAIL OR HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772. 15
The Pittsburgh radar (KPBZ), 98 km away, was scanning. The volume nearest the first event began at 23:05 UTC.
1 thunderstorm wind. Local standard time, as filed.
Law enforcement reported trees down at Greenville Sports complex and along Good Hope Rd.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2009Every state in 2009This day in weather historyWarnings in Pennsylvania, May 2009
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: 163211.