A mesoscale convective vortex ahead of a cold front over Lake Erie produced an area of thunderstorms with very heavy rainfall. Rainfall amounts across Beaver county reached more than 4 inches in 2 hours with reports of 2 to 3 inches in 2 hours common in other counties.
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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 mesoscale convective vortex ahead of a cold front over Lake Erie produced an area of thunderstorms with very heavy rainfall. Rainfall amounts across Beaver county reached more than 4 inches in 2 hours with reports of 2 to 3 inches in 2 hours common in other counties.
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 5, 5:47 AM EST, 5 hours 38 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 647 AM EDT THU JUL 5 2007 .SYNOPSIS... CONDITIONS WILL BE UNSTABLE TODAY AND EARLY TONIGHT AND RIPE FOR THE DEVELOPMENT OF POSSIBLY SEVERE THUNDERSTORMS AS MOIST LOWLEVEL AIR OVER OUR UPPER OHIO VALLEY REGION WILL BE TOPPED BY A PASSING COLD UPPER LOW PRESSURE SYSTEM MOVING EASTWARD THROUGH THE GREAT LAKES. THEN MIDWEST HIGH PRESSURE WILL BUILD ACROSS THE UPPER OHIO VALLEY AND PROVIDE DRY WEATHER FOR THIS WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... WITH DAYTIME HEATING, THE STRATUS/FOG WILL LIFT INTO STRATOCUMULUS AND CUMULUS. BY AFTERNOON, THE CUMULUS CAN GROW INTO CUMULONIMBUS AS THE CURRENT MOIST LOWLEVEL AIR MASS OVER THE UPPER OHIO VALLEY BECOMES TOPPED BY COLDER AIR ALOFT CAUSING A DEEP UNSTABLE LAYER. THE COLDER AIR ALOFT IS ASSOCIATED WITH A DEEPENING UPPER LONG-WAVE TROUGH AS SHOWN BY RECENT NAM AND GFS MODEL RUNS. SEVERAL LOW PRESSURE SYSTEMS MOVING THROUGH THIS STRENGTHENING NORTHWEST UPPER FLOW WILL PROVIDE THE LIFTING MECHANISM TO HELP FORM BANDS OF THUNDERSTORMS THIS AFTERNOON AND EARLY TONIGHT. CONCUR WITH SPC THINKING THAT THESE COULD BECOME SEVERE AS SREF MODEL RUNS CONTINUE TO SHOW CAPES GREATER THAN 1000 J/KG AND EFFECTIVE SHEAR VALUES OF 30-40 KTS. THE HWO WILL HIGHLIGHT THAT THE PRIME SEVERE THREAT WILL BE DAMAGING WIND AND THE SECONDARY THREAT LARGE HAIL. WITH NIGHTFALL, THE THUNDERSTORM THREAT WILL BEGIN TO ABATE AND LIKELY HAVE ENDED BY AROUND MIDNIGHT. THERE CAN BE PATCHES OF LATE NIGHT FOG INDUCED BY THE EVAPORATION OF SURFACE MOISTURE IN AREAS THAT GOT SUBSTANTIAL RAINS. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... NAM AND GFS MODEL RUNS SHOW HIGH PRESSURE FROM THE MIDWEST BUILDING INTO THE UPPER OHIO VALLEY THIS WEEKEND. THIS WILL HELP DRIER LOWLEVEL AIR AND MORE STABLE CONDITIONS TO COME INTO THE UPPER OHIO VALLEY. CONCUR WITH GFS AND NAM MOS VALUES, THAT TEMPERATURES WILL BE CLOSE TO NORMAL THIS PERIOD. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... BOTH RECENT GFS AND ECMWF MODEL RUNS SHOW THE UPPER JETSTREAM FLOW PATTERN BECOMING ZONAL EARLY NEXT WEEK. THIS MEANS THE HIGH PRESSURE THAT BROUGHT DRY, STABLE CONDITIONS THIS WEEKEND WILL MOVE EAST INTO THE ATLANTIC OCEAN. HENCE GULF MOISTURE AND ATTENDANT INSTABILITY WILL BE REINTRODUCED INTO THE UPPER OHIO VALLEY EARLY NEXT WEEK...REALIZING THE POTENTIAL FOR THUNDERSTORMS TO DEVELOP LATE MONDAY INTO TUESDAY. CONCUR WITH GFS MOS TEMPERATURE VALUES THAT SHOW A WARMER THAN NORMAL PERIOD EARLY NEXT WEEK. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... RECENT SATELLITE AND SURFACE DATA SHOW THE BANK OF STRATUS AND FOG ACROSS OHIO HAS EXPANDED INTO WESTERN PENNSYLVANIA AND NORTHERN WEST VIRGINIA. HOWEVER, DAYTIME HEATING AND MIXING WILL HELP THE STRATUS BANK TO LIFT INTO STRATOCUMULUS AND CUMULUS WITH MOST TAF SITES HAVING VFR FLIGHT CONDITIONS (P6SM BKN035) BY 15Z. STILL LOOKS AS THOUGH THUNDERSTORMS WITH SEVERE POTENTIAL CAN DEVELOP THIS AFTERNOON AND EARLY TONIGHT AS THE CURRENT MOIST LOWLEVEL AIR MASS BECOMES TOPPED BY COLDER TEMPERATURES ALOFT...RESULTING IN UNSTABLE CONDITIONS. THIS COLDER AIR ALOFT WILL BE ACCOMPANYING THE EASTWARD PASSAGE OF AN UPPER LOW PRESSURE SYSTEM THROUGH THE GREAT LAKES. RECENT RUC MODEL RUNS SHOW DEEP LAYER OF LIFT MOVING SOUTHEASTWARD THROUGH THE UPPER OHIO VALLEY THIS AFTERNOON, 17Z-20Z THROUGH THE KFKL-KDUJ CORRIDOR AND 20Z-23Z KZZV-KPIT-KLBE CORRIDOR AND SOUTH TO KMGW. THIS CONCURS WITH MOST SREF MEMBERS THAT SHOWED THE BEST CHANCE OF THUNDERSTORMS 18Z-03Z WITH SUFFICIENT EFFECTIVE SHEAR FOR SEVERE DEVELOPMENT AS INDICATED BY RECENT SPC THINKING. BRIEF IFR FLIGHT CONDITIONS CAN DEVELOP IN THE THUNDERSTORMS WITH HEAVIER RAIN. WINDS WILL GO FROM SOUTHSOUTHWEST 4-7KTS TO SOUTHWEST AND WESTSOUTHWEST 9-15KTS MIDDAY INTO EARLY EVENING. WIND GUSTS MAY BRIEFLY EXCEED 50KTS IN SEVERE THUNDERSTORMS. HOWEVER, IN TAFS, MENTIONED GUSTS NEAR 30KTS. LATE TONIGHT, THERE CAN BE POST-RAIN EVAPORATION-INDUCED PATCHY FOG AND STRATUS WITH MAINLY MVFR FLIGHT CONDITIONS. WITH RENEWAL OF DAYTIME HEATING AND MIXING FRIDAY, EXPECT VFR FLIGHT CONDITIONS, THAT WILL PERSIST THROUGH SUNDAY. AS LOWLEVEL MOISTURE BEGINS TO INCREASE LATE SUNDAY, THERE WILL BE A POSSIBILITY OF PATCHY MVFR FLIGHT CONDITIONS IN LATE NIGHT FOG EARLY MONDAY AND TUESDAY...AND IN MAINLY AFTERNOON AND NIGHTTIME THUNDERSTORMS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PITTSBURGH PA 427 AM EDT THU JUL 5 2007 MDZ001-OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023- 029>032-WVZ001>004-012-021>023-041-060830- 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- 427 AM EDT THU JUL 5 2007 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 THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THIS AFTERNOON INTO THIS EVENING. THE PRIMARY SEVERE WEATHER THREAT WILL BE DAMAGING WINDS AND LARGE HAIL. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THERE IS NO SEVERE WEATHER EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TODAY.
The Pittsburgh radar (KPBZ), 11 km away, was scanning. The volume nearest the first event began at 16:23 UTC.
10 flash flood, 2 flood, 1 thunderstorm wind. Local standard time, as filed.
A retired NWS employee reported flash flooding in Aliquippa, Monaca, and surrounding towns from rainfall of 3 to over 4 inches in 2 hours. Over 500 buildings and homes sustained damage across Beaver county with around 50 families displaced from homes.
Law enforcement reported roads closed in Shaler Township due to flash flooding.
Law enforcement reported roads closed due to flash flooding in Ross Township.
A trained spotter reported State Road 68 was closed due to flash flooding between Industry and Midland.
Emergency management reported water street closed due to flash flooding south of Maysville.
A trained spotter reported water in homes and streets closed due to flash flooding.
A trained spotter reported RT 18 1 mile north of I-70 closed due to flash flooding with Catfish Creek out of its banks.
Emergency management reported roads closed in Saltsburg due to flash flooding.
Emergency management reported that roads were closed in Avonmore with small streams out of their banks.
Flooding continued across Shaler and Ross townships with standing water across roads slowly receding.
Emergency management reported standing water on roads in Aliquippa and Monaca as well as surrounding towns. The water was slowly receding.
Emergency management reported roads closed and water in some homes due to flash flooding.
Emergency management reported trees down in the Sandy Lake and Stoneboro areas.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2007Every state in 2007This day in weather historyWarnings in Pennsylvania, July 2007
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: 48171, 48173, 48174, 48172, 48175, 48177, 48180, 48179, 48181, 48183, 48184, 48182, 48185.