Alert archive / Texas / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 249, NWS Norman, OK

April 29, 2009Clay County, Texas

NWS Norman, OK issued this severe thunderstorm warning at Apr 29, 2009, 1:31 PM CDT for Clay County, Texas. It was in force for 59 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Apr 29, 2009, 1:31 PM CDT (18:31 UTC)
Expired: Apr 29, 2009, 2:30 PM CDT
In force: 59 min
Issued by: NWS Norman, OK
Area: Storm-based polygon

County Clay County, TX

The radar

The Altus AFB radar (KFDR), 95 km from the middle of the area, began a volume at 18:35 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Apr 29, 12:36 PM CDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 6.5 hours before the alert went out and 136 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: 1229 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 462 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 130 m²/s²
0-3 km storm-relative helicity: 173 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.4

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Apr 29, 12:55 PM CDT, 36 minutes earlier.

Area forecast discussion, Apr 29, 12:55 PM CDT, 36 minutes before

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Hazardous weather outlook, Apr 29, 11:55 AM CDT, 1 hour 36 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORMAN OK
1155 AM CDT WED APR 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-
1155 AM CDT WED APR 29 2009

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

.DAY ONE...THIS AFTERNOON AND TONIGHT...

THUNDERSTORM OUTLOOK...
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
OKLAHOMA AND ALL OF WESTERN NORTH TEXAS THROUGH TONIGHT.

LOCATION...
THE SLIGHT RISK AREA COVERS AN AREA SOUTHWEST OF A LINE FROM
CHEROKEE... TO EL RENO... TO ADA AND ATOKA OKLAHOMA. THIS INCLUDES
ALL OF WESTERN NORTH TEXAS.

TIMING...
SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH 3 AM.

IMPACTS...
HAIL TO THE SIZE OF GOLF BALLS AND WIND GUSTS TO 70 MPH. AN ISOLATED
TORNADO CAN NOT BE RULED OUT.

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

DISCUSSION...
A LARGE AREA OF THUNDERSTORMS WILL CONTINUE TO DEVELOP AND MOVE
ACROSS PORTIONS OF SOUTHERN OKLAHOMA AND NORTH TEXAS THIS AFTERNOON.
MEANWHILE... A DRYLINE WILL CONTINUE TO DEVELOP ACROSS THE CENTRAL
PANHANDLES THIS AFTERNOON. AN UPPER LEVEL DISTURBANCE WILL ALSO MOVE
FROM THE SOUTHWEST U.S. ACROSS THE SOUTHERN PLAINS LATER TODAY AND
TONIGHT. WITH HEATING THE AIRMASS EAST OF THE DRYLINE IS EXPECTED TO
BECOME UNSTABLE LATER THIS AFTERNOON. ADDITIONAL SCATTERED
THUNDERSTORMS MAY DEVELOP NEAR AND EAST OF THE DRYLINE LATE THIS
AFTERNOON AND THIS EVENING MOVING ACROSS PORTIONS OF OKLAHOMA AND
WESTERN NORTH TEXAS TONIGHT. ANOTHER FOCUS FOR THUNDERSTORM
DEVELOPMENT IS AN OUTFLOW BOUNDARY FROM THE MORNING THUNDERSTORMS
THAT EXTENDS ACROSS NORTH TEXAS. SOME OF THE STORMS MAY BECOME
SEVERE THIS AFTERNOON AND TONIGHT ACROSS PARTS OF OKLAHOMA AND
WESTERN NORTH TEXAS... WITH LARGE HAIL AND STRONG WINDS THE MAIN
CONCERN. HOWEVER... AN ISOLATED TORNADO CAN NOT BE RULED OUT...
PRIMARILY IN THE AREA NEAR THE OUTFLOW BOUNDARY.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT THURSDAY APR 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...
EXCESSIVE RAINFALL FROM THUNDERSTORMS TODAY MAY RESULT IN FLASH
FLOODING ACROSS PORTIONS OF SOUTHERN OKLAHOMA AND WESTERN NORTH
TEXAS. A FLASH FLOOD WATCH IS IN AFFECT THROUGH 7 AM.

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

THUNDERSTORM OUTLOOK...
THE RISK OF SEVERE STORMS WILL CONTINUE EACH DAY THROUGH AT LEAST
FRIDAY... AND POSSIBLY INTO THE WEEKEND.

OTHER HAZARDOUS WEATHER...
PERIODS OF HEAVY RAINFALL ARE EXPECTED INTO EARLY NEXT WEEK...WHICH
COULD LEAD TO BOTH LOCALIZED FLOODING AND MAINSTEM RIVER FLOODING.

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

MAXWELL

In the hours before

Local storm report, Apr 29, 11:34 AM CDT, 1 hour 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NORMAN OK
1134 AM CDT WED APR 29 2009

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

1130 AM     HAIL             FILLMORE                34.27N 96.50W
04/29/2009  E0.75 INCH       JOHNSTON           OK   CO-OP OBSERVER

&&

DW/TY

Special weather statement, Apr 29, 12:38 PM CDT, 53 minutes before

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Local storm report, Apr 29, 12:56 PM CDT, 35 minutes before

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Local storm report, Apr 29, 1:06 PM CDT, 25 minutes before

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Special weather statement, Apr 29, 1:09 PM CDT, 22 minutes before

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Special weather statement, Apr 29, 1:12 PM CDT, 19 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
112 PM CDT WED APR 29 2009

TXZ087-291830-
KNOX TX-
112 PM CDT WED APR 29 2009

...SIGNIFICANT WEATHER ADVISORY...

THIS SIGNIFICANT WEATHER ADVISORY IS FOR KNOX COUNTY.

A LINE OF STRONG TO SEVERE THUNDERSTORMS WAS LOCATED FROM 6 MILES
SOUTHWEST OF KNOX CITY TO 33 MILES SOUTHWEST OF KNOX CITY AT 111 PM
CDT...MOVING NORTHEAST AT 25 MPH.

SOME HAIL AND WINDS OF 50 TO 60 MPH WILL BE POSSIBLE WITH THESE
STORMS AS WELL AS FREQUENT LIGHTNING AND VERY HEAVY RAINFALL.

PEOPLE IN KNOX COUNTY SHOULD MONITOR THE WEATHER SITUATION CLOSELY.
LISTEN FOR WARNINGS AND REMAIN ALERT FOR THREATENING WEATHER
CONDITIONS.

30

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 29, 2:06 AM CDT	Severe Thunderstorm Warning	OUN	Jackson	39 min
Apr 29, 2:09 AM CDT	Flash Flood Watch	OUN	Alfalfa, Blaine, Garfield, Grant, Kay, Kingfisher and 4 more	10 hr
Apr 29, 2:22 AM CDT	Areal Flood Advisory	OUN	Harper, Woods	3 hr
Apr 29, 2:43 AM CDT	Severe Thunderstorm Warning	OUN	Jackson, Tillman	62 min
Apr 29, 3:56 AM CDT	Severe Thunderstorm Warning	OUN	Jackson, Tillman	79 min
Apr 29, 4:07 AM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Greer, Jackson, Kiowa, Tillman	3 hr
Apr 29, 5:12 AM CDT	Areal Flood Warning	OUN	Caddo, Comanche, Kiowa, Tillman	4 hr
Apr 29, 6:41 AM CDT	Areal Flood Advisory	OUN	Caddo, Grady, Greer, Jackson, Kiowa, Tillman and 1 more	3 hr
Apr 29, 7:38 AM CDT	Areal Flood Advisory	OUN	Harmon, Jackson	3 hr
Apr 29, 8:07 AM CDT	Severe Thunderstorm Warning	OUN	Jefferson, Stephens	53 min
Apr 29, 8:18 AM CDT	Areal Flood Advisory	OUN	Cotton, Jefferson, Stephens	3 hr
Apr 29, 8:53 AM CDT	Flash Flood Warning	OUN	Cotton, Jefferson, Stephens	3 hr
Apr 29, 8:59 AM CDT	Severe Thunderstorm Warning	OUN	Carter, Jefferson, Stephens	61 min
Apr 29, 9:17 AM CDT	Areal Flood Advisory	OUN	Caddo, Comanche, Greer, Jackson, Kiowa, Tillman	3 hr
Apr 29, 9:58 AM CDT	Severe Thunderstorm Warning	OUN	Carter, Jefferson, Johnston, Love, Marshall, Murray	62 min
Apr 29, 10:06 AM CDT	Areal Flood Advisory	OUN	Carter, Garvin, Jefferson, Love, Murray	114 min
Apr 29, 10:07 AM CDT	Severe Thunderstorm Warning	OUN	Cleveland, Garvin, McClain, Murray, Pontotoc, Pottawatomie and 1 more	53 min
Apr 29, 10:18 AM CDT	Areal Flood Advisory	OUN	Canadian, Cleveland, Oklahoma	117 min
Apr 29, 10:34 AM CDT	River Flood Warning	OUN	Harper, Woods, Woodward	9 hr
Apr 29, 10:34 AM CDT	River Flood Warning	OUN	Major, Woods, Woodward	28 hr
Apr 29, 10:38 AM CDT	Severe Thunderstorm Warning	OUN	Coal, Hughes, Pontotoc, Seminole	67 min
Apr 29, 10:47 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan, Coal, Johnston, Marshall	58 min
Apr 29, 11:13 AM CDT	Areal Flood Advisory	OUN	Carter, Coal, Hughes, Johnston, Love, Marshall and 2 more	3 hr
Apr 29, 11:43 AM CDT	Severe Thunderstorm Warning	OUN	Atoka, Bryan	62 min
Apr 29, 11:51 AM CDT	Flash Flood Warning	OUN	Atoka, Bryan, Carter, Johnston, Love, Marshall	3 hr
Apr 29, 12:07 PM CDT	Flash Flood Watch	OUN	Atoka, Bryan, Carter, Comanche, Cotton, Jackson and 7 more	19 hr
Apr 29, 12:15 PM CDT	Areal Flood Advisory	OUN	Carter, Murray	2 hr
Apr 29, 1:07 PM CDT	Areal Flood Advisory	OUN	Jefferson	113 min
Apr 29, 1:37 PM CDT	Areal Flood Warning	OUN	Harmon, Jackson, Kiowa, Tillman	6 hr
Apr 29, 1:46 PM CDT	Areal Flood Warning	OUN	Cotton, Jefferson, Stephens	6 hr
Apr 29, 1:59 PM CDT	River Flood Warning	OUN	Oklahoma	7 hr
Apr 29, 1:59 PM CDT	River Flood Warning	OUN	Pottawatomie, Seminole	7 hr
Apr 29, 2:19 PM CDT	Areal Flood Warning	OUN	Carter, Love, Murray	6 hr
Apr 29, 2:29 PM CDT	River Flood Warning	OUN	Cotton	3 days
Apr 29, 4:08 PM CDT	Severe Thunderstorm Warning	OUN	Jefferson	67 min
Apr 29, 4:13 PM CDT	Areal Flood Warning	OUN	Marshall	6 hr
Apr 28, 10:28 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Knox	62 min
Apr 28, 11:29 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Hardeman	61 min
Apr 29, 12:29 AM CDT	Severe Thunderstorm Warning	OUN	Foard, Hardeman, Wilbarger	61 min
Apr 29, 1:05 AM CDT	Areal Flood Advisory	OUN	Foard, Hardeman	3 hr
Apr 29, 3:08 AM CDT	Severe Thunderstorm Warning	OUN	Hardeman, Wilbarger	52 min
Apr 29, 10:11 AM CDT	Areal Flood Advisory	OUN	Wichita	2 hr
Apr 29, 12:03 PM CDT	Flash Flood Warning	OUN	Clay, Wichita, Wilbarger	3 hr
Apr 29, 2:28 PM CDT	Severe Thunderstorm Warning	OUN	Clay	47 min
Apr 29, 2:59 PM CDT	Areal Flood Warning	OUN	Archer, Clay, Wichita	6 hr
Apr 29, 4:25 PM CDT	Flash Flood Warning	OUN	Clay	3 hr

Nearby

Severe Thunderstorm Warnings in Texas, 2009 Every severe thunderstorm 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.