Flash Flooding and Hail in Oklahoma, May 20 to 21, 2013

Name: Flash Flooding and Hail in Oklahoma, May 20 to 21, 2013
Start: 2013-05-20T23:30
End: 2013-05-21T15:08
Location: Oklahoma

May 20 to 21, 2013 · NWS OUN · 8 events in 7 counties and zones

A shortwave trough progressed through the southern Plains during the first part of the day, resulting in thunderstorm development over west Texas early in the morning. These storms intensified and expanded in coverage as they moved eastward into Oklahoma, with isolated reports of large hail in the most intense cores.

Where it happened

Every event with a place to put it. 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: 8

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 happened

The episode as NWS OUN wrote it up.

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 Norman, OK wrote its last area forecast discussion before the first event at May 20, 7:15 PM CST, 4 hours 15 minutes earlier.

Area forecast discussion, May 20, 7:15 PM CST, 4 hours 15 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
815 PM CDT MON MAY 20 2013

.UPDATE...
THUNDERSTORMS WILL CONTINUE TO AFFECT PARTS OF SOUTH CENTRAL AND
SOUTHEAST OK THIS EVENING. ADDITIONAL DEVELOPMENT WILL BE POSSIBLE
ACROSS PARTS OF CENTRAL/SOUTHERN OK OVERNIGHT/EARLY TUESDAY. MADE
SOME ADJUSTMENTS TO POPS/WX. WILL SEND UPDATES SHORTLY.

MAXWELL

&&

.PREV DISCUSSION... /ISSUED 152 PM CDT MON MAY 20 2013/

DISCUSSION...

..SEVERE THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING ACROSS
MUCH OF OKLAHOMA AND WESTERN NORTH TEXAS...

RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED OVER THE NEXT HOUR OR
TWO ALONG THE DRYLINE AND STATIONARY BOUNDARY. THIS WILL MAINLY
BE ALONG I44 FROM OKC SOUTHWARD...AND ALONG AND EAST OF I35 NORTH
OF OKC. RETURNS ALREADY BEING OBSERVED EAST OF LAWTON. MOST
RECENT MESOANALYSIS AND 18Z SOUNDING SUGGEST VERY LARGE HAIL AND
THE POSSIBILITY OF TORNADOES ESPECIALLY JUST SOUTH/SW OF METRO NE
OF TRIPLE POINT. STORMS SHOULD REMAIN DISCRETE UNTIL LATER
TONIGHT...PERHAPS MERGING ACROSS SOUTH CENTRAL/EAST CENTRAL OK
PRODUCING VERY HEAVY RAINFALL...HAIL...AND THE THREAT OF DAMAGING
WINDS ACROSS SE OK. ANOTHER ROUND OF ELEVATED CONVECTION MAY BE
POSSIBLE VERY LATE TONIGHT THROUGH EARLY TOMORROW MORNING AS
SHORTWAVE TROUGH IMPACTS THE AREA. COOLER TEMPS ARE EXPECTED
TOMORROW WITH THUNDERSTORMS CONTINUING PERHAPS THROUGH THE DAY
ACROSS SE OK.

A BREAK IN RAIN/THUNDERSTORM CHANCES WILL OCCUR WED...BUT WILL
RETURN THURS THROUGH SATURDAY AS SUBTLE SHORTWAVE TROUGHS ROUNDING
THE RIDGE AXIS IMPACT THE REGION AND ANOTHER WEAK COLD FRONT
ENTERS THE AREA. EXPECT NEAR AVG TEMPS THROUGH THE EXTENDED.

&&

.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK  64  76  60  84 /  30  30  10  10
HOBART OK         61  82  58  88 /  10  20  10  10
WICHITA FALLS TX  68  82  62  89 /  20  20  10  10
GAGE OK           54  81  53  85 /  10  10   0  10
PONCA CITY OK     59  78  55  80 /  20  20  10  10
DURANT OK         70  78  65  85 / 100  60  40  10

&&

.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&

25/99

Hazardous weather outlook, May 20, 8:41 PM CST, 2 hours 49 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
941 PM CDT MON MAY 20 2013

OKZ004>048-050>052-TXZ083>090-211000-
HARPER-WOODS-ALFALFA-GRANT-KAY-ELLIS-WOODWARD-MAJOR-GARFIELD-NOBLE-
ROGER MILLS-DEWEY-CUSTER-BLAINE-KINGFISHER-LOGAN-PAYNE-BECKHAM-
WASHITA-CADDO-CANADIAN-OKLAHOMA-LINCOLN-GRADY-MCCLAIN-CLEVELAND-
POTTAWATOMIE-SEMINOLE-HUGHES-HARMON-GREER-KIOWA-JACKSON-TILLMAN-
COMANCHE-STEPHENS-GARVIN-MURRAY-PONTOTOC-COAL-COTTON-JEFFERSON-
CARTER-JOHNSTON-ATOKA-LOVE-MARSHALL-BRYAN-HARDEMAN-FOARD-WILBARGER-
WICHITA-KNOX-BAYLOR-ARCHER-CLAY-
945 PM CDT MON MAY 20 2013

THIS HAZARDOUS WEATHER OUTLOOK COVERS NORTHERN...WESTERN...
CENTRAL...AND SOUTHERN OKLAHOMA...AND WESTERN NORTH TEXAS.

.DAY ONE...TONIGHT...

THUNDERSTORM OUTLOOK...
A MODERATE RISK OF SEVERE STORMS CONTINUES FOR SOUTHERN OKLAHOMA INTO
NORTH TEXAS...WITH A SLIGHT RISK OF SEVERE STORMS FROM NORTHERN
OKLAHOMA THROUGH WESTERN NORTH TEXAS.

LOCATION...
THE MODERATE RISK EXTENDS SOUTH OF A LINE FROM CALVIN TO SULPHUR TO
HENRIETTA TEXAS. THE SLIGHT RISK EXTENDS SOUTH OF A LINE FROM
MORRISON TO SEWARD TO YUKON TO LAWTON TO SEYMOUR TEXAS...COVERING
LOCATIONS SOUTH AND EAST TO THE MODERATE RISK.

TIMING...
SEVERE STORMS REMAIN ON GOING ACROSS FAR SOUTHERN OKLAHOMA AND NORTHERN
TEXAS. ELEVATED ISOLATED STORMS ALSO CONTINUE TO DEVELOP ACROSS CENTRAL
OKLAHOMA. THIS NEW DEVELOPMENT OF STORMS BEHIND THE PRIMARY FRONT IS
EXPECTED TO CONTINUE THROUGH THE EARLY MORNING HOURS.

IMPACTS...
THE TORNADO THREAT REMAINS...HOWEVER...LARGE DESTRUCTIVE HAIL AND DAMAGING
WINDS REMAIN THE PRIMARY CONCERNS. ONGOING STORMS HAVE BEEN CAPABLE OF
80 MPH WINDS AND BASEBALL SIZED HAIL.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREAS SHOULD PLAN TO CONTINUE SEVERE WEATHER OPERATIONS THROUGH
THE EARLY MORNING HOURS.

DISCUSSION...
OVERALL...THE FRONTAL BOUNDARY HAS STALLED FROM NORTHEASTERN THROUGH
CENTRAL OKLAHOMA...INTO WESTERN NORTH TEXAS. ONGOING STORMS REMAIN
ROOTED TO THIS BOUNDARY...AS IT CONTINUES TO PROVIDE LIFT FOR THE
CONTINUED DEVELOPMENT OF STORMS. INSTABILITY REMAINS SUFFICIENT ALONG
AND AHEAD OF THE BOUNDARY...WITH WIND FIELDS CONTINUING TO SUPPORT
ROTATING UPDRAFTS.

EXPECT GENERAL THUNDERSTORMS TO REDEVELOP LATER TONIGHT THROUGH
TUESDAY MORNING AS THE FRONT SLOWLY RETREATS NORTHWESTWARD OVERNIGHT.
WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED AT THIS TIME...HOWEVER
A FEW STRONG TO SEVERE STORMS CANNOT BE RULED OUT.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT TUESDAY MAY 21.
PROBABILITY OF THUNDERSTORMS OCCURRING IN THE
              NWS NORMAN COUNTY WARNING AREA...100 PERCENT.
PROBABILITY OF SEVERE STORMS IF STORMS OCCUR...100 PERCENT.

OTHER HAZARDOUS WEATHER...
CONTINUED TRAINING OF STORMS WILL RESULT IN INCREASED FLOODING OF CREEKS...
SMALL STREAMS...AND ROAD WAYS. THIS WILL BE ESPECIALLY TRUE ACROSS THE
RED RIVER VALLEY REGION.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...

THUNDERSTORM OUTLOOK...
SEVERE STORMS WILL BE POSSIBLE AGAIN ON TUESDAY...MAINLY ACROSS THE
SOUTHEAST HALF OF OKLAHOMA. ISOLATED SEVERE STORMS WILL BE POSSIBLE
EACH DAY FROM WEDNESDAY THROUGH FRIDAY. THUNDERSTORMS ARE NOT
CURRENTLY EXPECTED ON SATURDAY AND SUNDAY.

OTHER HAZARDOUS WEATHER...
NONE.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 5 AM
TUESDAY AND UPDATED AS NEEDED.

KURTZ

In the hours before

Special weather statement, May 20, 9:33 PM CST, 1 hour 57 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
1033 PM CDT MON MAY 20 2013

OKZ043-047-048-210400-
JOHNSTON OK-ATOKA OK-COAL OK-
1033 PM CDT MON MAY 20 2013

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN JOHNSTON...
NORTHWESTERN ATOKA AND COAL COUNTIES UNTIL 1100 PM CDT...

AT 1029 PM CDT...A STRONG THUNDERSTORM WAS LOCATED NEAR BROMIDE...
MOVING EAST AT 40 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...
WIND GUSTS TO 50 MPH...

LAT...LON 3444 9604 3433 9650 3450 9658 3451 9657
      3450 9651 3455 9651 3474 9622
TIME...MOT...LOC 0329Z 248DEG 34KT 3445 9646

Local storm report, May 20, 10:31 PM CST, 59 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1131 PM CDT MON MAY 20 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1126 PM     HAIL             DUNCAN                  34.52N 97.97W
05/20/2013  E1.25 INCH       STEPHENS           OK   LAW ENFORCEMENT

            AT STEPHENS COUNTY FAIRGROUNDS

&&

JPIKE

Special weather statement, May 20, 10:50 PM CST, 40 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
1150 PM CDT MON MAY 20 2013

OKZ028-029-040-210515-
MCCLAIN OK-GARVIN OK-CLEVELAND OK-
1150 PM CDT MON MAY 20 2013

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN MCCLAIN...NORTHERN
GARVIN AND SOUTHEASTERN CLEVELAND COUNTIES UNTIL 1215 AM CDT...

AT 1147 PM CDT...A STRONG THUNDERSTORM WAS LOCATED 4 MILES NORTH OF
MAYSVILLE...MOVING NORTHEAST AT 35 MPH.

HAZARDS INCLUDE...
HAIL UP TO THE SIZE OF NICKELS...

LAT...LON 3476 9745 3492 9756 3509 9723 3499 9714
      3494 9714 3493 9709
TIME...MOT...LOC 0447Z 238DEG 30KT 3489 9743

Local storm report, May 20, 10:53 PM CST, 37 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1153 PM CDT MON MAY 20 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1134 PM     HAIL             EMPIRE CITY             34.46N 98.04W
05/20/2013  E1.75 INCH       STEPHENS           OK   BROADCAST MEDIA

            FROM KSWO

&&

JPIKE

Local storm report, May 20, 11:27 PM CST, 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1227 AM CDT TUE MAY 21 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1127 PM     HAIL             WYNNEWOOD               34.64N 97.16W
05/20/2013  E1.00 INCH       GARVIN             OK   PUBLIC

            PUBLIC REPORTED HAIL COVERING GROUND...DIMES TO QUARTERS.

&&

KURTZ

Local storm report, May 20, 11:29 PM CST, 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1229 AM CDT TUE MAY 21 2013

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1226 AM     HAIL             ADA                     34.78N 96.66W
05/21/2013  E1.00 INCH       PONTOTOC           OK   BROADCAST MEDIA

&&

KURTZ

The radar

The Norman radar (KTLX), 83 km away, was scanning. The volume nearest the first event began at 05:29 UTC.

Open the radar archive at this moment

Event by event

6 hail, 2 flash flood. Local standard time, as filed.

Hail, Pontotoc

When: May 20, 11:30 PM CST
Where: Pontotoc County, 1.33 mi ENE of Ada
Measured: 1.25 in hail
Reported by: Public
Coordinates: 34.780, -96.660

No damage was reported.

Hail, Greer

When: May 21, 9:17 AM CST
Where: Greer County, Granite
Measured: 1.25 in hail
Reported by: Public
Coordinates: 34.960, -99.380

Hail, Kiowa

When: May 21, 9:19 AM CST
Where: Kiowa County, Lone Wolf
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 34.990, -99.250

Hail, Caddo

When: May 21, 10:14 AM CST
Where: Caddo County, Eakly
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 35.310, -98.560

Hail, Caddo

When: May 21, 10:20 AM CST
Where: Caddo County, Binger
Measured: 1.75 in hail
Reported by: Amateur Radio
Coordinates: 35.310, -98.340

Hail, Canadian

When: May 21, 10:40 AM CST
Where: Canadian County, 12.79 mi SSW of Calumet
Measured: 1.5 in hail
Reported by: Public
Coordinates: 35.430, -98.210

Flash Flood, Atoka

When: May 21, 1:08 PM CST to 3:08 PM CST
Where: Atoka County, 0.33 mi WNW of Atoka to 0.34 mi NNW of Atoka
Cause: Heavy Rain
Reported by: Public
Coordinates: 34.383, -96.135

Flooding and road closures reported at the 900 block of W 6th St. and the 700 block of E 6th St. No damage was reported.

Flash Flood, Coal

When: May 21, 1:25 PM CST to 2:25 PM CST
Where: Coal County, 4.55 mi NE of Cottonwood to 4.51 mi NE of Cottonwood
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 34.608, -96.146

Water over highway 37 at the Keel Creek bridge. No damage was reported.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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 Oklahoma in 2013 Every state in 2013 This day in weather history Warnings in Oklahoma, May 2013

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: 454913, 451660, 451661, 451662, 451663, 451664, 454909, 454910.