Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 231, NWS Norman, OK

April 26, 2009Grady County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 26, 2009, 10:59 PM CDT for Grady County, Oklahoma. It was in force for 23 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 26, 2009, 10:59 PM CDT (03:59 UTC)
Expired: Apr 26, 2009, 11:22 PM CDT
In force: 23 min
Issued by: NWS Norman, OK
Area: Storm-based polygon

County Grady County, OK

The radar

The Norman radar (KTLX), 65 km from the middle of the area, began a volume at 04:01 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 26, 6:16 PM CDT	Tornado Watch PDS	SPC	8 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 4.0 hours before the alert went out and 49 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: 617 J/kg
Mixed-layer CIN: -175 J/kg
Mixed-layer LCL: 936 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 359 m²/s²
0-3 km storm-relative helicity: 443 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 3.8

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 26, 7:28 PM CDT, 3 hours 31 minutes earlier.

Area forecast discussion, Apr 26, 7:28 PM CDT, 3 hours 31 minutes before

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Hazardous weather outlook, Apr 26, 8:55 PM CDT, 2 hours 4 minutes before

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In the hours before

Special weather statement, Apr 26, 9:43 PM CDT, 1 hour 16 minutes before

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Local storm report, Apr 26, 9:44 PM CDT, 1 hour 15 minutes before

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Special weather statement, Apr 26, 9:57 PM CDT, 1 hour 2 minutes before

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Special weather statement, Apr 26, 10:04 PM CDT, 55 minutes before

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Special weather statement, Apr 26, 10:15 PM CDT, 44 minutes before

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Local storm report, Apr 26, 10:20 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 26, 7:11 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant, Woods	64 min
Apr 26, 7:13 PM CDT	Areal Flood Advisory	OUN	Ellis, Harper, Major, Woods, Woodward	4 hr
Apr 26, 7:15 PM CDT	Severe Thunderstorm Warning	OUN	Caddo, Canadian, Washita	60 min
Apr 26, 7:16 PM CDT	Severe Thunderstorm Warning	OUN	Woodward	59 min
Apr 26, 7:19 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Major, Woods	41 min
Apr 26, 7:30 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Jackson, Tillman	60 min
Apr 26, 7:44 PM CDT	Areal Flood Advisory	OUN	Ellis, Harper, Woods, Woodward	3 hr
Apr 26, 7:59 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Woods, Woodward	61 min
Apr 26, 8:10 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant	65 min
Apr 26, 8:24 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Tillman	66 min
Apr 26, 10:22 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Grady, Stephens	38 min
Apr 27, 3:52 AM CDT	River Flood Warning	OUN	Major, Woods, Woodward	29 hr
Apr 27, 1:07 PM CDT	Severe Thunderstorm Warning	OUN	Logan, Payne	38 min
Apr 27, 1:18 PM CDT	Severe Thunderstorm Warning	OUN	Noble	27 min
Apr 27, 1:24 PM CDT	Severe Thunderstorm Warning	OUN	Payne	51 min
Apr 27, 2:34 PM CDT	River Flood Warning	OUN	Grant, Kay	42 hr
Apr 26, 7:44 PM CDT	Severe Thunderstorm Warning	OUN	Foard, Hardeman, Wilbarger	35 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 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.