Alert archive / Texas / Tornado Watches in 2009

Tornado Watch 222

May 1, 200922 counties in Oklahoma; 27 counties in Texas

The Storm Prediction Center issued this tornado watch at May 1, 2009, 3:09 PM CDT for 22 counties in Oklahoma; 27 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: May 1, 2009, 3:09 PM CDT (20:09 UTC)
Expired: May 1, 2009, 10:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 3 in
Strongest gust expected: 70 kt

All 49 counties

Atoka County, OK, Bryan County, OK, Carter County, OK, Cleveland County, OK, Coal County, OK, Comanche County, OK, Cotton County, OK, Garvin County, OK, Grady County, OK, Hughes County, OK, Jackson County, OK, Jefferson County, OK, Johnston County, OK, Love County, OK, Marshall County, OK, McClain County, OK, Murray County, OK, Pontotoc County, OK, Pottawatomie County, OK, Seminole County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Childress County, TX, Clay County, TX, Cooke County, TX, Cottle County, TX, Dickens County, TX, Fannin County, TX, Fisher County, TX, Foard County, TX, Grayson County, TX, Hardeman County, TX, Haskell County, TX, Jack County, TX, Jones County, TX, Kent County, TX, King County, TX, Knox County, TX, Montague County, TX, Motley County, TX, Shackelford County, TX, Stonewall County, TX, Throckmorton County, TX, Wichita County, TX, Wilbarger County, TX, Wise County, TX, Young County, TX

The radar

The Altus AFB radar (KFDR), 50 km from the middle of the area, began a volume at 20:10 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 50%
Ten or more severe hail reports: 70%
One or more hailstones of 2 inches or more: 80%
Six or more combined severe hail and wind reports: 90%

Warnings issued inside it

28 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 1, 3:09 PM CDT	Severe Thunderstorm Warning	OUN	Knox	66 min
May 1, 3:43 PM CDT	Severe Thunderstorm Warning	SJT	Haskell	47 min
May 1, 3:52 PM CDT	Tornado Warning	SJT	Haskell	38 min
May 1, 4:14 PM CDT	Tornado Warning	SJT	Haskell	31 min
May 1, 4:26 PM CDT	Severe Thunderstorm Warning	OUN	Baylor, Foard, Knox, Wilbarger	64 min
May 1, 4:38 PM CDT	Severe Thunderstorm Warning	LUB	King	32 min
May 1, 4:42 PM CDT	Tornado Warning	SJT	Haskell	33 min
May 1, 4:50 PM CDT	Severe Thunderstorm Warning	LUB	Stonewall	26 min
May 1, 5:11 PM CDT	Tornado Warning	SJT	Haskell	34 min
May 1, 5:14 PM CDT	Flash Flood Warning	OUN	Baylor, Foard, Knox	4 hr
May 1, 5:28 PM CDT	Severe Thunderstorm Warning	OUN	Baylor, Foard, Hardeman, Knox, Wilbarger	62 min
May 1, 5:33 PM CDT	Tornado Warning	SJT	Haskell, Jones	27 min
May 1, 5:40 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Tillman	65 min
May 1, 5:52 PM CDT	Severe Thunderstorm Warning	SJT	Haskell, Shackelford	23 min
May 1, 6:18 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Tillman	44 min
May 1, 6:23 PM CDT	Severe Thunderstorm Warning	OUN	Baylor	40 min
May 1, 6:32 PM CDT	Severe Thunderstorm Warning	SJT	Throckmorton	29 min
May 1, 7:36 PM CDT	Severe Thunderstorm Warning	LUB	Kent, Stonewall	24 min
May 1, 8:02 PM CDT	Severe Thunderstorm Warning	SJT	Haskell	58 min
May 1, 8:06 PM CDT	Severe Thunderstorm Warning	SJT	Fisher	54 min
May 1, 8:31 PM CDT	Severe Thunderstorm Warning	SJT	Fisher, Jones	59 min
May 1, 8:33 PM CDT	Tornado Warning	SJT	Haskell	42 min
May 1, 8:59 PM CDT	Severe Thunderstorm Warning	SJT	Jones, Shackelford	61 min
May 1, 9:00 PM CDT	Severe Thunderstorm Warning	OUN	Knox	30 min
May 1, 9:14 PM CDT	Severe Thunderstorm Warning	SJT	Haskell	31 min
May 1, 9:18 PM CDT	Severe Thunderstorm Warning	OUN	Baylor	30 min
May 1, 9:18 PM CDT	Severe Thunderstorm Warning	SJT	Jones	27 min
May 1, 9:42 PM CDT	Severe Thunderstorm Warning	SJT	Jones, Shackelford	63 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 8.2 hours before the alert went out and 188 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: 1780 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 552 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 30, 7:54 PM CDT	Severe Thunderstorm Watch	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more	5 hr
Apr 30, 11:41 PM CDT	Mesoscale Discussion	SPC	Beckham, Blaine, Caddo, Canadian, Cleveland, Custer and 15 more	64 min
May 1, 12:45 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Canadian, Cherokee, Cleveland, Craig, Creek and 29 more	6 hr
May 1, 3:00 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Craig, Creek, Delaware, Garfield and 16 more	2 hr
May 1, 6:08 AM CDT	Mesoscale Discussion	SPC	Adair, Alfalfa, Cherokee, Craig, Creek, Delaware and 18 more	67 min
May 1, 7:26 AM CDT	Severe Thunderstorm Watch	SPC	Adair, Cherokee, Cleveland, Creek, Garfield, Grant and 27 more	7 hr
May 1, 10:32 AM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Mayes, Noble, Osage, Pawnee and 5 more	58 min
May 1, 1:22 PM CDT	Mesoscale Discussion	SPC	Adair, Cherokee, Cleveland, Creek, Garfield, Grant and 20 more	53 min
May 1, 2:48 PM CDT	Mesoscale Discussion	SPC	Carter, Cotton, Jefferson, Love, Murray	87 min

Nearby

Tornado Watches in Texas, 2009 Tornado Watches in Oklahoma, 2009 Every tornado watch 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.