Storms continued into the 28th as a slow moving trough approached. Early morning convection produced numerous flood reports. Later in the day, renewed storm development led to an isolated supercell which tracked across southern portions of the OKC metro area with 2-3 diameter hail and damaging winds. Extensive damage was reported with this storm, with the most significant damage concentrated in Norman. In Cleveland County, the hail and wind caused over 2 million dollars in damage just to county-owned buildings. While exact numbers for private homes, businesses and vehicles are not available, damage estimates are easily into the hundreds of millions of dollars.

Flash Flood in CLEVELAND, OKLAHOMA
From 28-APR-21 20:10:00 to 28-APR-21 23:10:00 (CST-6)
Location: NORMAN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: State Official

Half a dozen streets closed from flooding,  mostly on the northwest side of town.

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 20:12:00 to 28-APR-21 20:12:00 (CST-6)
Location: NORMAN
Magnitude: 3.00 
Crop damage: 0.00K
Reported by: NWS Employee

Measured 3.2 inch hailstone.

Thunderstorm Wind in POTTAWATOMIE, OKLAHOMA
From 28-APR-21 20:34:00 to 28-APR-21 20:34:00 (CST-6)
Location: PINK
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Emergency Manager

Windows blown out on the west side of a house.

Thunderstorm Wind in POTTAWATOMIE, OKLAHOMA
From 28-APR-21 20:35:00 to 28-APR-21 20:35:00 (CST-6)
Location: DALE
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Emergency Manager

Significant roof damage at a home around the Shawnee twin lakes area.

Hail in POTTAWATOMIE, OKLAHOMA
From 28-APR-21 20:38:00 to 28-APR-21 20:38:00 (CST-6)
Location: DALE
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POTTAWATOMIE, OKLAHOMA
From 28-APR-21 21:22:00 to 28-APR-21 21:22:00 (CST-6)
Location: JOHNSON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Flash Flood in BRYAN, OKLAHOMA
From 29-APR-21 01:00:00 to 29-APR-21 04:00:00 (CST-6)
Location: ACHILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

At least 2 structures took on water.

Thunderstorm Wind in CLEVELAND, OKLAHOMA
From 28-APR-21 20:00:00 to 28-APR-21 20:00:00 (CST-6)
Location: NORMAN
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Flash Flood in GARVIN, OKLAHOMA
From 28-APR-21 06:47:00 to 28-APR-21 09:47:00 (CST-6)
Location: PERNELL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Facebook post from Elmore city fire  department of a car in flooded water due to road collapse. Time is estimated from radar storm total.

Flash Flood in PONTOTOC, OKLAHOMA
From 28-APR-21 07:44:00 to 28-APR-21 10:44:00 (CST-6)
Location: ADA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter reported 6-12 inches of water with water rushing into some homes.

Flash Flood in PONTOTOC, OKLAHOMA
From 28-APR-21 08:30:00 to 28-APR-21 11:30:00 (CST-6)
Location: ADA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Videos/pictures on twitter of water rushing over streets/bridges in Ada. Time was  documented at the time of the tweet. Multiple vehicles stranded and roads impassible in other parts of the county.

Flash Flood in HUGHES, OKLAHOMA
From 28-APR-21 09:00:00 to 28-APR-21 12:00:00 (CST-6)
Location: YEAGER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hughes county emergency manager reported multiple roads in Hughes county that are  washed out and impassible. Time is estimated  based off the timing of the maximum storm total rainfall.

Flash Flood in CLEVELAND, OKLAHOMA
From 28-APR-21 14:59:00 to 28-APR-21 17:59:00 (CST-6)
Location: MOORE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Flooded streets in Norman posted on Twitter.

Thunderstorm Wind in GRADY, OKLAHOMA
From 28-APR-21 19:15:00 to 28-APR-21 19:15:00 (CST-6)
Location: POCASSET
Magnitude: 70.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Significant damage to a roof and barn and broken poles.

Thunderstorm Wind in GRADY, OKLAHOMA
From 28-APR-21 19:28:00 to 28-APR-21 19:28:00 (CST-6)
Location: POCASSET
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRADY, OKLAHOMA
From 28-APR-21 19:34:00 to 28-APR-21 19:34:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in GRADY, OKLAHOMA
From 28-APR-21 19:34:00 to 28-APR-21 19:34:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Two to three inch tree branches broken off of a tree.

Thunderstorm Wind in GRADY, OKLAHOMA
From 28-APR-21 19:38:00 to 28-APR-21 19:38:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated wind gust.

Hail in GRADY, OKLAHOMA
From 28-APR-21 19:38:00 to 28-APR-21 19:38:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Flash Flood in PONTOTOC, OKLAHOMA
From 28-APR-21 07:45:00 to 28-APR-21 10:45:00 (CST-6)
Location: ADA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Mping report.

Flash Flood in PONTOTOC, OKLAHOMA
From 28-APR-21 08:15:00 to 28-APR-21 11:15:00 (CST-6)
Location: ADA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Lake in the park on the southeast side of Ada is 8-12 inches over the bank.

Flash Flood in COMANCHE, OKLAHOMA
From 28-APR-21 14:49:00 to 28-APR-21 17:49:00 (CST-6)
Location: MEERS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Report of water 2 inches of water over highway.

Flood in CLEVELAND, OKLAHOMA
From 28-APR-21 15:32:00 to 28-APR-21 18:32:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Mping report, flooding in flood-prone areas.

Flood in CLEVELAND, OKLAHOMA
From 28-APR-21 16:55:00 to 28-APR-21 19:55:00 (CST-6)
Location: MOORE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Tweet with picture of a road that has high water across the road. Looks to be impassible.

Hail in GRADY, OKLAHOMA
From 28-APR-21 19:38:00 to 28-APR-21 19:38:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Public

Significant damage to mobile home siding reported.

Hail in MCCLAIN, OKLAHOMA
From 28-APR-21 19:43:00 to 28-APR-21 19:43:00 (CST-6)
Location: NEWCASTLE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in MCCLAIN, OKLAHOMA
From 28-APR-21 19:44:00 to 28-APR-21 19:44:00 (CST-6)
Location: BLANCHARD
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MCCLAIN, OKLAHOMA
From 28-APR-21 19:45:00 to 28-APR-21 19:45:00 (CST-6)
Location: NEWCASTLE
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Estimated severe wind gusts.

Hail in MCCLAIN, OKLAHOMA
From 28-APR-21 19:45:00 to 28-APR-21 19:45:00 (CST-6)
Location: NEWCASTLE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:53:00 to 28-APR-21 19:53:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Public

Significant window damage reported.

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:53:00 to 28-APR-21 19:53:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:54:00 to 28-APR-21 19:54:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 1.25 
Crop damage: 0.00K
Reported by: Public

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:55:00 to 28-APR-21 19:55:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:55:00 to 28-APR-21 19:55:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Significant damage to cars at dealerships between Robinson and main along I-35 in Norman.

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:57:00 to 28-APR-21 19:57:00 (CST-6)
Location: NORMAN
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:57:00 to 28-APR-21 19:57:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Broken car windows and west-facing windows at an apartment complex.

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:58:00 to 28-APR-21 19:58:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Public

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 19:59:00 to 28-APR-21 19:59:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 2.50 
Crop damage: 0.00K
Reported by: NWS Employee

Estimated 2-3 inch hail reported.

Thunderstorm Wind in CLEVELAND, OKLAHOMA
From 28-APR-21 20:00:00 to 28-APR-21 20:00:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in CLEVELAND, OKLAHOMA
From 28-APR-21 20:00:00 to 28-APR-21 20:00:00 (CST-6)
Location: NORMAN
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: NWS Employee

Measured 2.77 inch. Windows and skylights broken.

Flash Flood in CLEVELAND, OKLAHOMA
From 28-APR-21 20:05:00 to 28-APR-21 23:05:00 (CST-6)
Location: MOORE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Water rescue in a vehicle reported.