Flash Flooding and Damaging Winds in Ohio, July 21, 2001

Name: Flash Flooding and Damaging Winds in Ohio, July 21, 2001
Start: 2001-07-21T16:35
End: 2001-07-21T21:15
Location: Ohio

July 21, 2001 · NWS ILN · 6 events in 3 counties and zones

4 flash flood, 2 thunderstorm wind, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 6

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.

What forecasters said that day

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 Wilmington, OH wrote its last area forecast discussion before the first event at Jul 21, 1:55 PM EST, 2 hours 40 minutes earlier.

Area forecast discussion, Jul 21, 1:55 PM EST, 2 hours 40 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON OH
255 PM EDT SAT JUL 21 2001

REGIONAL RADAR IMAGERY INDICATES CONVECTION HAS INCREASED IN
COVERAGE OVER NORTHERN INDIANA AND FAR SOUTHWESTERN MI.  SATELLITE
IMAGERY SHOWING CU OVER FA AND MESOSCALE CONVECTIVE VORT OVER
SOUTHEASTERN IL.

MODELS ARE ALL IN GOOD AGREEMENT WITH SYNOPTIC FEATURES BUT VARY
WITH INTENSITY AND TIMING OF MID LEVEL WAVES.  RIDGE TO OUR WEST
WILL SLOWLY BREAK DOWN IN THE NEXT 24 TO 48 HOURS.  AS IT BREAKS
DOWN IT FLATTENS OUT BRINGING HIGHER HEIGHTS.  THE UPPER JET
STREAM...HOWEVER DOES REMAIN NORTH.

WILL LEAVE IN MENTION OF EVENING THUNDERSTORMS IN THE WEST AS BEST
INSTABILITY...WEAK LOW LEVEL CONVERGENCE AND OUTFLOW BOUNDARIES WILL
CREATE SCATTERED THUNDERSTORM ACTIVITY.  THINK CONVECTION OVER
NORTHERN IN WILL REMAIN NORTH BUT IT DOES BEAR WATCHING.  WILL KEEP
THE THREAT OVERNIGHT ACROSS THE SOUTH AS MOISTURE AXIS AND WEAK WAVE
REMAINS.  WILL THROUGH IN MENTION AGAIN SUNDAY AFTERNOON FOR SIMILAR
REASONS.  FEEL MONDAY WILL BE MAINLY DRY AS UPPER RIDGE BUILDS IN.
HOWEVER WILL INCLUDE 30 POP TO NORTHWEST...WHICH WILL BE CLOSER TO
THE FRONT.

TEMPS WILL GRADUALLY CLIMB A DEGREE OR TWO THE NEXT SEVERAL DAYS AS
WE HEAD INTO OUR LONGEST HOT SPELL OF THE SUMMER.  LOWS WILL HAVE A
TOUGH TIME FALLING BELOW 70 UNTIL LATTER IN THE WEEK.  FWC TEMPS
LOOK GOOD WILL ONLY MAKE MINOR TWEAKS.

.ILN...NONE.
 TIPTON

The radar

The Northern Indiana radar (KIWX), 126 km away, was scanning. The volume nearest the first event began at 21:35 UTC.

Open the radar archive at this moment

Event by event

4 flash flood, 2 thunderstorm wind. Local standard time, as filed.

Thunderstorm Wind, Mercer

When: July 21, 4:35 PM EST to 4:38 PM EST
Where: Mercer County, Mendon
Measured: 50 kt (58 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 40.667, -84.517

Thunderstorms produced strong winds which knocked down trees.

Thunderstorm Wind, Auglaize

When: July 21, 4:50 PM EST to 4:53 PM EST
Where: Auglaize County, St Marys
Measured: 50 kt (58 mph)
Reported by: LAW ENFORCEMENT
Coordinates: 40.533, -84.383

Thunderstorms produced strong winds which knocked down a tree and large limbs.

Flash Flood, Auglaize

When: July 21, 5:00 PM EST to 6:30 PM EST
Where: Auglaize County, St Marys
Reported by: TRAINED SPOTTER
Coordinates: 40.561, -84.222 (the zone’s center; the record gives no point)

Thunderstorms produced heavy rain which caused a foot of water to flow over Deep Cut Road.

Flash Flood, Mercer

When: July 21, 6:15 PM EST to 6:30 PM EST
Where: Mercer County, Celina
Reported by: LAW ENFORCEMENT
Coordinates: 40.540, -84.629 (the zone’s center; the record gives no point)

Thunderstorms produced heavy rain which caused high water on roads including U.S. Rte 33.

Flash Flood, Butler

When: July 21, 7:45 PM EST to 8:00 PM EST
Where: Butler County, Monroe
Reported by: LAW ENFORCEMENT
Coordinates: 39.439, -84.576 (the zone’s center; the record gives no point)

Thunderstorms produced heavy rain which caused Gregory Creek to overflow its banks.

Flash Flood, Butler

When: July 21, 8:00 PM EST to 9:15 PM EST
Where: Butler County, Trenton
Reported by: LAW ENFORCEMENT
Coordinates: 39.439, -84.576 (the zone’s center; the record gives no point)

Thunderstorms produced heavy rain which caused a road to be closed.

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Ohio in 2001 Every state in 2001 This day in weather history Warnings in Ohio, July 2001

Sources

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: 5257030, 5257031, 5257032, 5257033, 5257034, 5257035.