During the evening and nighttime hours of May 11th, an area of low pressure located over southern Wisconsin slowly progressed northeast over the upper Great Lakes. A frontal boundary extended southeast of the low, across portions of Indiana into southern Ohio.
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 CLE wrote it up.
During the evening and nighttime hours of May 11th, an area of low pressure located over southern Wisconsin slowly progressed northeast over the upper Great Lakes. A frontal boundary extended southeast of the low, across portions of Indiana into southern Ohio. That frontal boundary lifted north during the day on May 12 and stalled directly over northern Ohio. Thunderstorms developed along this boundary and produced large hail and significant rainfall throughout the day on May 12th. The severe thunderstorms and flash flooding continued through May 13th.
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 May 12, 3:28 AM EST, 47 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 428 AM EDT THU MAY 12 2011 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE AREA TODAY. UPPER LEVEL LOW PRESSURE OVER THE CENTRAL PLAINS WILL MOVE OVER THE AREA FRIDAY NIGHT AND LINGER THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WARM THAT WAS STALLED ACROSS SW OHIO FINALLY MOVING AND JUST SOUTHWEST OF THE AREA. TSRA OVER NW AND NC OH DEVELOPED IN AREA OF SURFACE CONVERGENCE AND SHOULD GRADUALLY WEAKEN AS THEY MOVE EAST. DEW POINTS EAST OF CLEVELAND STILL IN THE 40S. TSRA WILL LINGER UNTIL MID MORNING BEFORE DISSIPATING. MODELS SHOW UPPER RIDGE FINALLY SHIFTING EAST. EXPECT ANOTHER ROUND OF TSRA THIS AFTERNOON NEAR BOUNDARY. SPC HAS ENTIRE AREA UNDER SLIGHT RISK THIS AFTERNOON. CAPES PUSH TO 1500-2000 J/KG NEAR AND SOUTH OF THE WARM FRONT THIS AFTERNOON. IN ADDITION SOME LIFT FROM NOSE OF 300 MB JET PUSHING INTO MID MISSISSIPPI VALLEY THIS AFTERNOON...NOT TO MENTION BOUNDARIES FROM TSRA THIS MORNING. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... UNSETTLED FORECAST CONTINUES THROUGH THE WEEKEND. MODELS CONTINUE TO MOVE THE UPPER LEVEL LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS OVER THE AREA FRIDAY NIGHT. UPPER LOW WILL LINGER OVER THE AREA THROUGH THE WEEKEND KICKING OFF SHOWERS AND TSRA ON AND OFF THROUGH THE WEEKEND. EVEN THOUGH THE MODELS ARE COMING INTO BETTER AGREEMENT...AS ECMWF NOW COMING INTO BETTER AGREEMENT WITH THE GFS. DID NOT TIME BANDS OF TSRA...JUST WENT LIKELY POPS THROUGH THE WEEKEND...WITH GRADUALLY COOLING TEMPS. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... THE MODELS ARE TRENDING CLOSER TOGETHER EARLY NEXT WEEK BUT THE ECMWF CONTINUES TO BRING THE LAST UPPER LOW FARTHER NORTH AND WEST THAN THE OTHER MODELS. THE ECMWF SOLUTION RETROGRADES THE RAIN BACK ACROSS THE FORECAST AREA ON TUESDAY AND WEDNESDAY WHERE THE OTHER MODELS SLIDE IT OFF TO THE SOUTH AND EAST. NOT MUCH CONFIDENCE IN ANY PARTICULAR MODEL BUT TYPICALLY THESE CLOSED LOW EVENTS SLOWLY MOVE OFF TO THE EAST. WILL CONTINUE WITH THE CURRENT FORECAST OF SLOWLY DRYING THINGS OUT BY TUESDAY AND WEDNESDAY ALTHOUGH WILL KEEP A "SLIGHT CHANCE" IN THE FORECAST CONSIDERING THE UNCERTAINTY. TEMPERATURES ARE TRICKY SINCE A RAINY DAY WITH A NORTH FLOW THIS TIME OF YEAR CAN BE QUITE CHILLY WHEREAS TEMPERATURES WILL DRIFT UPWARD ON A DRY DAY. IN ANY CASE...IT WILL BE RATHER COOL EARLY IN THE WEEK ESPECIALLY NEAR THE LAKESHORE. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... SHOWERS AND STORMS WILL SLIDE ACROSS PARTS OF NORTHWEST AND NORTH CENTRAL OHIO INCLUDING LAKE ERIE EARLY THIS MORNING. OUTSIDE OF THE SHOWER ACTIVITY...CONDITIONS WILL REMAIN VFR. MOST OF THE AREA WILL HAVE MORE INSTABILITY AND HUMIDITY TODAY AND EXPECT MORE CUMULUS THAN RECENT DAYS BETWEEN 4-6K. THE WEAK WARM FRONT WILL BE NEAR THE I-77 CORRIDOR THIS AFTERNOON AND EXPECT SHOWERS AND STORMS TO REDEVELOP OVER NORTHEAST OHIO. THE EXACT TIMING IS UNCERTAIN. .OUTLOOK...SCATTERED NON-VFR IN CONVECTION THIS EVENING CONTINUING THROUGH THE WEEKEND. && .MARINE... THE WARM FRONT WILL STRUGGLE TO MOVE NORTH OF LAKE ERIE TODAY AND THE FLOW WILL LIKELY STAY MAINLY FROM THE EAST. THE GRADIENT IS WEAKENING SO THERE IS LESS RISK OF ANY SIGNIFICANT WIND AND WAVES BUT THE WESTERN HALF OF THE LAKE WILL STILL BE A LITTLE CHOPPY. THE WIND SHOULD VEER MORE TOWARD THE SOUTH BY TOMORROW. THE NEXT SURFACE LOW APPEARS AS IF IT WILL TRACK SOUTH OF LAKE ERIE OVER THE WEEKEND AND THE WIND WILL PROBABLY VEER BACK TOWARD TO NORTHEAST AGAIN BY SUNDAY. THE GRADIENT MAY BE ENOUGH COMBINED WITH THE LONG FETCH TO STIR THE LAKE UP AGAIN BY SUNDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && SYNOPSIS...DJB NEAR TERM...DJB SHORT TERM...DJB LONG TERM...KOSARIK AVIATION...KOSARIK MARINE...KOSARIK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CLEVELAND OH 544 AM EDT WED MAY 11 2011 LEZ142>146-162>166-OHZ003-006>011-017>021-027>032-036>038-047-120945- 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- 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-LUCAS-WOOD-OTTAWA- SANDUSKY-ERIE OH-LORAIN-CUYAHOGA-HANCOCK-SENECA-HURON-MEDINA-SUMMIT- WYANDOT-CRAWFORD-RICHLAND-ASHLAND-WAYNE-STARK-MARION-MORROW-HOLMES- KNOX- 544 AM EDT WED MAY 11 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR LAKE ERIE...NORTH CENTRAL OHIO...NORTHEAST OHIO AND NORTHWEST OHIO. .DAY ONE...TODAY AND TONIGHT. SCATTERED THUNDERSTORMS ARE POSSIBLE IN NORTHWEST AND NORTH CENTRAL OHIO TODAY AND TONIGHT. A FEW OF THE STRONGER THUNDERSTORMS COULD APPROACH SEVERE LIMITS. BRIEF HEAVY RAINS ARE ALSO LIKELY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS THE POSSIBILITY FOR STRONG TO SEVERE THUNDERSTORMS THURSDAY AND THURSDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. LEZ061-147>149-167>169-OHZ012>014-022-023-033-089-PAZ001>003-120945- LAKE ERIE OPEN WATERS FROM RIPLEY TO BUFFALO NY-WILLOWICK TO GENEVA- ON-THE LAKE OH-GENEVA-ON-THE-LAKE TO CONNEAUT OH- CONNEAUT OH TO RIPLEY NY- 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-LAKE-GEAUGA- ASHTABULA INLAND-PORTAGE-TRUMBULL-MAHONING-ASHTABULA LAKESHORE- NORTHERN ERIE-SOUTHERN ERIE-CRAWFORD PA- 544 AM EDT WED MAY 11 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR LAKE ERIE...NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS THE POSSIBILITY FOR STRONG TO SEVERE THUNDERSTORMS THURSDAY AND THURSDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CLEVELAND OH 213 AM EDT THU MAY 12 2011 OHZ003-006>010-017>020-027>030-036>038-047-120645- ASHLAND OH-WYANDOT OH-CRAWFORD OH-HANCOCK OH-HOLMES OH-HURON OH-KNOX OH-LORAIN OH-MARION OH-MEDINA OH-MORROW OH-RICHLAND OH-SENECA OH-WOOD OH-LUCAS OH-OTTAWA OH-SANDUSKY OH-ERIE OH- 213 AM EDT THU MAY 12 2011 THUNDERSTORMS WILL CROSS PARTS OF NORTHWEST AND NORTH CENTRAL OHIO EARLY THIS MORNING. THE STORMS WILL PRODUCE HEAVY DOWNPOURS...HAIL AND LIGHTNING. THE STORMS WERE MOVING EAST AT 25 MPH. KOSARIK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CLEVELAND OH 253 AM EDT THU MAY 12 2011 OHZ003-006>009-017>019-027>030-036-037-047-120800- ASHLAND OH-WYANDOT OH-CRAWFORD OH-HANCOCK OH-HURON OH-KNOX OH- MARION OH-MORROW OH-RICHLAND OH-SENECA OH-WOOD OH-LUCAS OH-OTTAWA OH- SANDUSKY OH-ERIE OH- 253 AM EDT THU MAY 12 2011 THUNDERSTORMS WILL CROSS PARTS OF NORTHWEST AND NORTH CENTRAL OHIO EARLY THIS MORNING. THE STORMS WILL PRODUCE HEAVY DOWNPOURS... HAIL...BRIEF GUSTY WINDS AND LIGHTNING. THE STORMS WERE MOVING EAST AT 25 MPH.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CLEVELAND OH 415 AM EDT THU MAY 12 2011 OHZ003-006>010-018>020-028>031-038-047-120930- ASHLAND OH-CRAWFORD OH-HOLMES OH-HURON OH-KNOX OH-LORAIN OH-MEDINA OH-RICHLAND OH-SENECA OH-WAYNE OH-WOOD OH-LUCAS OH-OTTAWA OH-SANDUSKY OH-ERIE OH- 415 AM EDT THU MAY 12 2011 THUNDERSTORMS WILL CROSS PARTS OF NORTHWEST AND NORTH CENTRAL OHIO EARLY THIS MORNING. THE STORMS WILL PRODUCE HEAVY DOWNPOURS... HAIL...BRIEF GUSTY WINDS AND LIGHTNING. THE STORMS WERE MOVING EAST AT 25 MPH.
The Cleveland radar (KCLE), 71 km away, was scanning. The volume nearest the first event began at 09:16 UTC.
21 hail, 5 thunderstorm wind, 5 flash flood, 4 flood. Local standard time, as filed.
Half dollar sized hail was reported during this thunderstorm. Several vehicles were damaged by hail.
Thunderstorms produced pea to quarter sized hail. Small tree limbs were also downed with these thunderstorms.
Thunderstorms produced quarter size hail.
Thunderstorms produced plain M&M to penny sized hail.
Thunderstorms produced a swath of quarter to golf ball sized hail. Numerous vehicles were damaged by hail. Homes and crops were also damaged as a result of the large hail.
Thunderstorms produced a swath of penny to quarter sized hail.
Thunderstorms produced quarter sized hail.
Thunderstorms produced penny to nickel sized hail.
Thunderstorms produced quarter sized hail.
Thunderstorms produced nickel to quarter sized hail.
Thunderstorms produced a swath of pea to quarter sized hail.
Thunderstorms produced penny to nickel sized hail.
Thunderstorms produced quarter size hail and winds of 60mph to 70mph.
Thunderstorm winds snapped several large trees. Several roofs were damaged during this event.
Thunderstorms produced a swath of hail ranging in size from penny to half dollar to golf ball. Numerous vehicles and homes were damaged by the large hail. Crops were also damaged as a result of the hail.
Thunderstorms produced quarter sized hail.
Thunderstorms produced a swath of pea to quarter sized hail.
Thunderstorms produced quarter sized hail.
Thunderstorm winds downed two large trees.
Thunderstorms produced nickel sized hail.
Thunderstorm winds downed two large trees.
Torrential rainfall from strong thunderstorms brought as much as 1.5-2 to portions of Trumbull County. The rain fell at a high rate of over an inch per hour. This excessive rainfall caused water to runoff into streets as deep at 7-8 in the city of Leavittsburg.
Strong thunderstorms with torrential rain brought as much as 2 inches of rain in 1.5 hrs over portions of Cuyahoga County. The runoff from this rainfall cause flooding along Boston Road in Broadview Heights. Other Roads across the county were effected like Brookpark, State Road, and Crocker Road. A minor mudslide occurred along I-480 eastbound near Garfield Heights.
Torrential rain in severe thunderstorms produced localized flooding over portions of Medina. Numerours roads had water several inches deep with a few isolated road closures. State Rout 42 and 162 were flooded. Doppler Radar estimated as much as 1.75 inches of rain fell within an hour.
Thunderstorms with torrential rainfall moved over Mahoning County during the early evening hours of the 12th. Rainfall rates exceded 1 per hour, with doppler radar estimates of 1 to 2.5 falling over northern Mahoning County. The heaviest rain fell near Youngstown, with basement flooding and some road closures along RT 422 near the Metropark.
Torrential Rainfall from severe thunderstorms brought upwards of 3 inches of rainfall over portions of Lake County within an hour and a half. In the town of Concord flash flooding was reported. The Big Creek and Gardon Creeks came out of banks, and several roads were flooded. Some homes were threatened by the flood waters along Jason and Christian Ave.
Thunderstorms produced dime sized hail.
Thunderstorm winds downed a few large tree limbs.
Thunderstorms produced quarter to golf ball size hail. Numerous vehicles and homes were damaged by the hail. The large hail also damaged crops in the area.
Thunderstorms produced nickel to golf ball sized hail during this event. Vehicles and homes were damaged by the large hail.
Thunderstorm winds downed a large tree and a large tree limb.
Torrential rain with rates over an inch per hour fell over northwest portions of Trumbull County. As much as 2 inches fell within an hour and a half. Several roads were flooded including Route 45. Water levels came up so fast in some local streams and creeks that farm animals had to be rescued in Farmington.
Torrential rain developed along the boundary between the lake breeze and a stationary front over Lake County. The result was doppler radar estimated rainfall amounts around 2 to 2.5 within an hour and a half. This heavy rainfall resulted in flash flooding over portions of Madison Township. River Road, Ford Road, Madison Road, and Union Streets flooded with over a foot of water. Some depths were over the hoods of cars.
Sheriff Department reported a small dam failulre near the town of Orwell. This low head dam released enough water to wash out a road. The dam failure was the result of rapid runoff overwhelming the dam. Rainfall amounts of 2 to 3 inches fell in the area according to Doppler Radar estimates.
Strong thunderstorms with torrential rainfall developed over northern Ashland County. Doppler Weather Radar estimated 1 to 2.5 inches of rainfall over a two hour timespan fell during the evening hours. This rainfall resulted in several creeks and streams overspilling their banks. A rescue was conducted near the town of Rowsburg.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2011Every state in 2011This day in weather historyWarnings in Ohio, May 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: 307519, 307522, 307521, 307550, 307529, 307523, 307734, 307524, 307703, 307705, 307525, 307535, 307536, 307530, 307534, 307738, 307520, 307696, 307732, 307725, 307708, 309230, 309231, 309232, 309233, 309229, 307740, 309247, 309248, 309249, 309250, 309235, 309234, 309238, 309239.