Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 127, NWS Norman, OK

April 25, 20114 counties in Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 25, 2011, 7:24 PM CDT for 4 counties in Oklahoma. It was in force for 26 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 25, 2011, 7:24 PM CDT (00:24 UTC)
Expired: Apr 25, 2011, 7:50 PM CDT
In force: 26 min
Issued by: NWS Norman, OK
Area: Storm-based polygon

Counties Comanche County, OK, Greer County, OK, Jackson County, OK, Kiowa County, OK

The radar

The Altus AFB radar (KFDR), 47 km from the middle of the area, began a volume at 00:27 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

Amarillo Airport, TX (KAMA), launched 00:00Z, 0.4 hours before the alert went out and 241 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: 4 J/kg
Mixed-layer CIN: -179 J/kg
Mixed-layer LCL: 1571 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 160 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.1

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 25, 6:42 PM CDT, 42 minutes earlier.

Area forecast discussion, Apr 25, 6:42 PM CDT, 42 minutes before

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Hazardous weather outlook, Apr 25, 4:58 PM CDT, 2 hours 26 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE NORMAN OK
458 PM CDT MON APR 25 2011

OKZ004>048-050>052-TXZ083>090-261100-
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-
458 PM CDT MON APR 25 2011

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

.DAY ONE...THROUGH TONIGHT...

THUNDERSTORM OUTLOOK...
ISOLATED SEVERE THUNDERSTORMS ARE EXPECTED IN PORTIONS OF WESTERN
OKLAHOMA AND WESTERN NORTH TEXAS INTO THIS EVENING.

DISCUSSION...
A VIGOROUS UPPER LEVEL JET AND TROUGH WILL EJECT FROM THE SOUTHERN
ROCKIES OUT INTO THE SOUTHERN PLAINS THIS EVENING. THESE FEATURES
WILL PROVIDE SUFFICIENT LIFT TO GENERATE THUNDERSTORMS...AND STRONG
WIND SHEAR THAT WILL YIELD A FEW SEVERE STORMS.

COLD AIR ALOFT ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL RESULT IN
STEEP MID LEVEL LAPSE RATES...A FAVORABLE THERMODYNAMIC ENVIRONMENT
FOR THE PRODUCTION OF LARGE HAIL. ISOLATED THUNDERSTORMS CAPABLE OF
PRODUCING HAIL TO THE SIZE OF GOLFBALLS OR LARGER ARE EXPECTED
THROUGH AT LEAST EARLY EVENING IN PORTIONS OF WESTERN OKLAHOMA AND
WESTERN NORTH TEXAS. STORM INTENSITY IS EXPECTED TO DECREASE AFTER
SUNSET WITH THE LOSS OF SOLAR HEATING.

PROBABILITY TABLE...
VALID THROUGH 700 AM CDT TUESDAY APR 26.
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...
DRY AND BREEZY CONDITIONS WILL ELEVATE THE WILDFIRE POTENTIAL FOR A
FEW HOURS THIS AFTERNOON AND EVENING IN PORTIONS OF WESTERN NORTH
TEXAS.

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

THUNDERSTORM OUTLOOK...
ANOTHER STRONG UPPER LEVEL DISTURBANCE WILL EJECT FROM THE ROCKIES
ON TUESDAY EVENING. ALTHOUGH THE RICH FEED OF GULF MOISTURE WILL BE
LOCATED SOUTH AND EAST OF THE NORMAN FORECAST AREA...A FEW SEVERE
STORMS WILL BE POSSIBLE...AS THE DISTURBANCE WILL GENERATE VERY
STRONG LIFT. ONE CLUSTER OF STRONG STORMS WILL ARRIVE INTO NORTHWEST
OKLAHOMA LATE IN THE DAY...AND MAY EVENTUALLY REACH OTHER PARTS OF
OKLAHOMA AND NORTH TEXAS. MEANWHILE...ANOTHER CLUSTER OF STORMS WILL
LIKELY AFFECT SOUTHEAST OKLAHOMA...AS SURFACE LOW PRESSURE PASSES
NEARBY.

THE CHANCE OF THUNDERSTORMS WILL END EARLY WEDNESDAY...AND DRY
WEATHER IS THEN EXPECTED THROUGH AT LEAST FRIDAY. THERE IS A CHANCE
THAT ANOTHER STORM SYSTEM WILL APPROACH NEXT WEEKEND.

OTHER HAZARDOUS WEATHER...
NONE.

THE NEXT SCHEDULED HAZARDOUS WEATHER OUTLOOK WILL BE ISSUED AT 5 AM
TUESDAY.

In the hours before

Special weather statement, Apr 25, 5:38 PM CDT, 1 hour 46 minutes before

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Special weather statement, Apr 25, 5:59 PM CDT, 1 hour 25 minutes before

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Special weather statement, Apr 25, 6:14 PM CDT, 1 hour 10 minutes before

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Local storm report, Apr 25, 6:35 PM CDT, 49 minutes before

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Special weather statement, Apr 25, 6:42 PM CDT, 42 minutes before

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Special weather statement, Apr 25, 6:45 PM CDT, 39 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
Apr 25, 7:15 PM CDT	Special Weather Statement	OUN	Comanche, Tillman	30 min
Apr 25, 7:17 PM CDT	Special Weather Statement	OUN	Kiowa	28 min
Apr 25, 8:03 PM CDT	Special Weather Statement	OUN	Carter, Comanche, Garvin, Grady, Greer, Jackson and 6 more	57 min
Apr 26, 4:21 PM CDT	Special Weather Statement	OUN	Atoka	24 min
Apr 26, 4:25 PM CDT	Severe Thunderstorm Warning	OUN	Atoka	10 min
Apr 26, 4:39 PM CDT	Special Weather Statement	OUN	Atoka	21 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2011 Every severe thunderstorm warning in 2011

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.