Alert archive / Oklahoma / Flash Flood Warnings in 2009

Flash Flood Warning 20, NWS Norman, OK

July 30, 2009Caddo County, Comanche County, Grady County, Oklahoma

NWS Norman, OK issued this flash flood warning at Jul 30, 2009, 1:33 AM CDT for Caddo County, Comanche County, Grady County, Oklahoma. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 30, 2009, 1:33 AM CDT (06:33 UTC)
Expired: Jul 30, 2009, 5:30 AM CDT
In force: 4 hr
Issued by: NWS Norman, OK
Area: Storm-based polygon
Flood severity: None

Counties Caddo County, OK, Comanche County, OK, Grady County, OK

The radar

The Altus AFB radar (KFDR), 94 km from the middle of the area, began a volume at 06:35 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 6.6 hours before the alert went out and 252 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 915 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 1329 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 136 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, 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 this flash flood warning went out at Jul 30, 12:43 AM CDT, 50 minutes earlier.

Area forecast discussion, Jul 30, 12:43 AM CDT, 50 minutes before

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Hazardous weather outlook, Jul 29, 9:35 PM CDT, 3 hours 58 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE NORMAN OK
935 PM CDT WED JUL 29 2009

OKZ004>048-050>052-TXZ083>090-301000-
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-
935 PM CDT WED JUL 29 2009

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

.DAY ONE...TONIGHT...

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MOST OF
WESTERN NORTH TEXAS AND OKLAHOMA.

LOCATION...
THE RISK AREA COVERS ALL OF WESTERN NORTH TEXAS AND LOCATIONS
NORTHWEST OF A WAURIKA TO COALGATE LINE IN OKLAHOMA.

TIMING...
THE MOST LIKELY TIME FOR SEVERE THUNDERSTORMS WILL BE THROUGH 3 AM.

IMPACTS...
HAIL UP TO THE SIZE OF GOLFBALLS MAY DAMAGE CARS...ROOFS...AND
VEGETATION. WIND GUSTS TO 70 MPH MAY DAMAGE OUT-BUILDINGS AND
TREES...AND ALSO TOPPLE POWER POLES.

RECOMMENDED ACTIONS...
STORM SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL ACROSS THE
RISK AREA SHOULD PLAN FOR SEVERE WEATHER OPERATIONS THIS EVENING AND
OVERNIGHT.

DISCUSSION...
NUMEROUS THUNDERSTORMS DEVELOP ACROSS MUCH OF WESTERN AND CENTRAL
OKLAHOMA AS A WEAK UPPER LEVEL DISTURBANCE MOVES OVER AN UNCAPPED
AIRMASS. ADDITIONAL STORMS WILL MOVE INTO WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS FROM THE PANHANDLES. HAIL TO THE SIZE OF
GOLFBALLS AND DAMAGING WIND GUSTS OF 70 MPH WILL BE POSSIBLE WITH
THE STRONGER STORMS. IN ADDITION TO THESE SEVERE WEATHER THREATS...
TORRENTIAL RAINFALL AND INTENSE LIGHTNING CAN BE EXPECTED.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT THURSDAY JUL 30.
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...
VERY HEAVY RAINFALL MAY CAUSE LOCAL FLOODING... ESPECIALLY IN THOSE
LOCATIONS THAT HAVE ALREADY RECEIVED SEVERAL INCHES OF RAIN OVER THE
PAST COUPLE OF DAYS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

THUNDERSTORM OUTLOOK...
ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE INTO EARLY
THURSDAY ACROSS PARTS OF WESTERN NORTH TEXAS AND SOUTHERN AND
EASTERN OKLAHOMA. THE NORTHWESTERLY FLOW PATTERN WILL PERSIST ACROSS
THE REGION INTO THE WEEKEND... RESULTING IN AT LEAST A SLIGHT CHANCE
OF THUNDERSTORMS EACH DAY THROUGH SUNDAY.

OTHER HAZARDOUS WEATHER...
NONE.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED BY 5 AM
THURSDAY.

In the hours before

Local storm report, Jul 30, 12:11 AM CDT, 1 hour 22 minutes before

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Special weather statement, Jul 30, 12:14 AM CDT, 1 hour 19 minutes before

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Special weather statement, Jul 30, 12:28 AM CDT, 1 hour 5 minutes before

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Local storm report, Jul 30, 1:10 AM CDT, 23 minutes before

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Special weather statement, Jul 30, 1:11 AM CDT, 22 minutes before

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Local storm report, Jul 30, 1:21 AM CDT, 12 minutes before

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The office that day

Everything else NWS Norman, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 29, 8:36 PM CDT	Severe Thunderstorm Warning	OUN	Custer, Dewey	54 min
Jul 29, 9:20 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Grady	55 min
Jul 29, 9:28 PM CDT	Severe Thunderstorm Warning	OUN	Custer, Washita	62 min
Jul 29, 9:32 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Roger Mills	58 min
Jul 29, 10:04 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Grady	56 min
Jul 29, 10:08 PM CDT	Severe Thunderstorm Warning	OUN	Washita	67 min
Jul 29, 10:28 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Greer, Roger Mills	62 min
Jul 29, 10:39 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Greer, Harmon, Jackson	51 min
Jul 29, 10:58 PM CDT	Severe Thunderstorm Warning	OUN	Greer, Harmon, Jackson, Kiowa, Tillman	62 min
Jul 29, 11:06 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Comanche	54 min
Jul 29, 11:17 PM CDT	Areal Flood Advisory	OUN	Beckham, Greer, Harmon, Kiowa, Washita	4 hr
Jul 29, 11:18 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Caddo, Comanche, Greer, Kiowa, Washita	57 min
Jul 30, 12:01 AM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Jackson, Kiowa, Tillman	59 min
Jul 30, 12:51 AM CDT	Areal Flood Advisory	OUN	Comanche, Grady	4 hr
Jul 30, 1:00 AM CDT	Severe Thunderstorm Warning	OUN	Cotton, Jefferson	60 min
Jul 30, 3:14 AM CDT	Areal Flood Advisory	OUN	Blaine, Kingfisher, Logan	3 hr
Jul 30, 4:59 AM CDT	Areal Flood Advisory	OUN	Oklahoma	2 hr
Jul 30, 5:45 AM CDT	Areal Flood Advisory	OUN	Lincoln	3 hr
Jul 30, 6:02 AM CDT	Flash Flood Warning	OUN	Lincoln	3 hr

Nearby

Flash Flood Warnings in Oklahoma, 2009 Every flash flood warning in 2009

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.