An upper level disturbance moved across northwest Pennsylvania on the morning of July 18th. Isolated severe thunderstorms fired up around lunchtime that day, and the event lasted a short period of time.
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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 CLE wrote it up.
An upper level disturbance moved across northwest Pennsylvania on the morning of July 18th. Isolated severe thunderstorms fired up around lunchtime that day, and the event lasted a short period of time.
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 Cleveland, OH wrote its last area forecast discussion before the first event at Jul 18, 8:22 AM EST, 2 hours 46 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 922 AM EDT MON JUL 18 2011 .SYNOPSIS... HIGH PRESSURE EXTENDED FROM THE TENNESSEE VALLEY EAST TO THE MID ATLANTIC COAST EARLY TODAY. TO OUR NORTH A WEAK COLD FRONT EXTENDED FROM THE DAKOTAS TO QUEBEC. THE HIGH WILL DRIFT SOUTH AND ALLOW THE COLD FRONT TO DROP INTO THE AREA TUESDAY. THE FRONT WILL RETREAT BACK TO THE NORTH WEDNESDAY AS HIGH PRESSURE BUILDS BACK TO THE REGION. && .NEAR TERM /THROUGH TODAY/... CONVECTION NW OF AREA HAS MOSTLY DISSIPATED. RUC SEEMS TO CURRENTLY HAVE BETTER HANDLE ON SITUATION THAN HRRR. AS DEBRIS CLOUDS DISSIPATE...TEMPS WARM AND AIRMASS DESTABILIZES...PROBABLY WILL SEE SOME CONVECTION REDEVELOP WITH WAVE OF ENERGY MOVING SE FROM EARLIER BAND OF CONVECTION. ESE MOVEMENT OF CELLS SHOULD MEAN LAKESHORE WILL HAVE A HARD TIME SEEING AND ACTIVITY. STORMS THAT DO OCCUR MAY MARGINALLY HAVE ENOUGH ENERGY FOR A FEW TO BECOME SEVERE. SEE NO REASON TO ADJUST HIGHS AND DEWPOINTS SO SHOULD ONLY APPROACH HEAT ADVISORY CRITERIA FOR THE AFTERNOON SO WILL CONTINUE WITH NO ADVISORY. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER PICTURE ACROSS THE AREA THROUGH THE NEAR TERM MAKING FOR QUITE HOT AFTERNOONS THROUGH MID WEEK AND BEYOND. BEST CHANCE OF RAIN WILL COME THIS EVENING AS AN EXTENSION FOR TODAY...AND THEN TONIGHT AND EARLY TUESDAY AS A WEAK COLD FRONT DROPS INTO THE AREA FROM THE NORTH. THE FRONT HEADS BACK NORTH AS A WARM FRONT TUESDAY NIGHT/WEDNESDAY. OTHERWISE WOULD EXPECT A SLIGHT CHANCE OF AN AFTERNOON OR EARLY EVENING SHOWER OR THUNDERSTORM WILL BE THE LIMIT. TEMPS LOOK A DEGREE OR TWO LOWER TUESDAY THAN TODAY BUT WEDNESDAY HIGHS SHOULD RETURN BACK TO NEAR 90 OR SO MOST AREAS. THURSDAY WARMER STILL AND POSSIBLY THE FIRST SOLID HEAT ADVISORY DAY WITH TEMPS IN THE MID 90S. && .LONG TERM /FRIDAY THROUGH SUNDAY/... HOT AND HUMID WILL CONTINUE WELL INTO THE EXTENDED FORECAST. GIVEN WITH THE WARM AND UNSTABLE AIRMASS EXPECTED...A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED OUT ANY OF THE PERIODS FROM FRIDAY THROUGH SUNDAY. HOWEVER...IT APPEARS THAT BEST CHANCES FOR PRECIP COULD COME LATE SATURDAY AS A WEAK TROUGH PASSES ACROSS THE AREA. ECMWF A LITTLE FASTER WITH THE TROUGH THAN THE GFS. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... A FEW LINGERING SHOWERS OVER LAKE ERIE ALL THAT IS LEFT OF LINE OF TSRA OF LINE OF TSRA OVER NRN MICHIGAN EARLIER. COULD GET A FEW SPRINKLES...OR A RUMBLE OF THUNDER NEAR ERIE PA EARLY THIS MORNING BUT LITTLE ELSE. SPC HAS ALL OF NRN OH/NW PA IN SLIGHT RISK FOR SEVERE TSRA THIS AFTERNOON INTO THE OVERNIGHT. TIMING OF TSRA DEVELOPMENT IS STILL IN QUESTION AT THIS POINT. THIS AFTERNOON CAPES INCREASE TO 1500-2500 J/KG...BUT STRONG CAP OF 12C AT 10K FT WILL INHIBIT DEVELOPMENT WITH NO TRIGGER. NAM DEVELOPS TSRA THIS AFTERNOON WHILE GFS LATER TRENDING ON LATER THIS EVENING INTO THE OVERNIGHT. TEND TO THINK THAT NAM IS A BIT FAST JUDGING BY STRENGTH OF THE RIDGE SO FOR TAFS WENT VCTS LATE AFTERNOON/EARLY EVENING TIME FRAME. OUTLOOK...VFR EXCEPT THUNDERSTORMS INTO THE OVERNIGHT AND REDUCED VSBY DURING EARLY MORNING FOG/HAZE. && .MARINE... QUIET WEATHER WILL CONTINUE ON THE LAKE. SOUTH WINDS WILL TURN TO THE SOUTHWEST LATER TODAY. THUNDERSTORMS WILL BE A THREAT THIS AFTERNOON AND EVENING. ON TUESDAY VARIABLE FLOW IS EXPECTED AS A WEAK LOW TRACKS ACROSS THE REGION...ONSHORE FLOW WILL LIKELY DEVELOP IN THE NEARSHORE WATERS DURING THE AFTERNOON. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && SYNOPSIS...TK NEAR TERM...ADAMS/TK SHORT TERM...TK LONG TERM...DJB AVIATION...DJB MARINE...DJB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CLEVELAND OH 519 AM EDT MON JUL 18 2011 OHZ003-006>014-017>023-027>033-036>038-047-089-PAZ001>003-190930- LUCAS-WOOD-OTTAWA-SANDUSKY-ERIE OH-LORAIN-CUYAHOGA-LAKE-GEAUGA- ASHTABULA INLAND-HANCOCK-SENECA-HURON-MEDINA-SUMMIT-PORTAGE-TRUMBULL- WYANDOT-CRAWFORD-RICHLAND-ASHLAND-WAYNE-STARK-MAHONING-MARION-MORROW- HOLMES-KNOX-ASHTABULA LAKESHORE-NORTHERN ERIE-SOUTHERN ERIE- CRAWFORD PA- 519 AM EDT MON JUL 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL OHIO...NORTHEAST OHIO...NORTHWEST OHIO AND NORTHWEST PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. THE STORM PREDICTION CENTER HAS DETERMINED THAT THERE IS A SLIGHT CHANCE THAT THUNDERSTORMS COULD TURN SEVERE TODAY AND TONIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. WEDNESDAY THROUGH SUNDAY...HIGH TEMPERATURES ARE EXPECTED TO REACH INTO THE LOW TO MID 90S ACROSS MUCH OF THE AREA. THIS COMBINED WITH HIGH HUMIDITY LEVELS COULD PUSH THE HEAT INDEX ABOVE 100 DURING THE AFTERNOON HOURS FOR A LARGE PORTION OF NORTHERN OHIO AND NORTHWEST PENNSYLVANIA. AS THE HEAT INDEX CLIMBS ABOVE 100...THE DANGER OF HEAT RELATED DISORDERS INCREASE. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED. LEZ061-142>149-162>169-190930- LAKE ERIE OPEN WATERS FROM RIPLEY TO BUFFALO NY- MAUMEE BAY TO RENO BEACH OH-RENO BEACH TO THE ISLANDS OH- THE ISLANDS TO VERMILION OH-VERMILION TO AVON POINT OH- AVON POINT TO WILLOWICK OH-WILLOWICK TO GENEVA-ON-THE LAKE OH-GENEVA- ON-THE-LAKE TO CONNEAUT OH-CONNEAUT OH TO RIPLEY NY- LAKE ERIE OPEN WATERS FROM MAUMEE BAY TO RENO BEACH- LAKE ERIE OPEN WATERS FROM RENO BEACH TO THE ISLANDS- LAKE ERIE OPEN WATERS FROM THE ISLANDS TO VERMILION- LAKE ERIE OPEN WATERS FROM VERMILION TO AVON POINT- LAKE ERIE OPEN WATERS FROM AVON POINT TO WILLOWICK- LAKE ERIE OPEN WATERS FROM WILLOWICK TO GENEVA-ON-THE-LAKE- LAKE ERIE OPEN WATERS FROM GENEVA-ON-THE-LAKE TO CONNEAUT- LAKE ERIE OPEN WATERS FROM CONNEAUT OH TO RIPLEY NY- 519 AM EDT MON JUL 18 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR LAKE ERIE. .DAY ONE...TODAY AND TONIGHT. THE STORM PREDICTION CENTER HAS DETERMINED THAT THERE IS A SLIGHT CHANCE THAT THUNDERSTORMS COULD TURN SEVERE TODAY AND TONIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED.
The Pittsburgh radar (KPBZ), 122 km away, was scanning. The volume nearest the first event began at 16:08 UTC.
2 thunderstorm wind. Local standard time, as filed.
An automated observing station measured a wind gust of 60mph with the thunderstorms.
Thunderstorm winds downed several large trees and power lines.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2011Every state in 2011This day in weather historyWarnings in Pennsylvania, July 2011
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: 327611, 327616.