Alert archive / Texas / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 283

May 11, 201121 counties in Arkansas; McCurtain County, Oklahoma; 50 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 11, 2011, 3:46 PM CDT for 21 counties in Arkansas; McCurtain County, Oklahoma; 50 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: May 11, 2011, 3:46 PM CDT (20:46 UTC)
Expired: May 12, 2011, 12:00 AM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 72 counties

Clark County, AR, Conway County, AR, Garland County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Johnson County, AR, Lafayette County, AR, Little River County, AR, Logan County, AR, Miller County, AR, Montgomery County, AR, Nevada County, AR, Newton County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Scott County, AR, Sevier County, AR, Yell County, AR, McCurtain County, OK, Anderson County, TX, Bell County, TX, Blanco County, TX, Bosque County, TX, Bowie County, TX, Burnet County, TX, Camp County, TX, Cass County, TX, Coryell County, TX, Delta County, TX, Ellis County, TX, Falls County, TX, Fannin County, TX, Franklin County, TX, Freestone County, TX, Gillespie County, TX, Gregg County, TX, Hamilton County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Kimble County, TX, Lamar County, TX, Lampasas County, TX, Leon County, TX, Limestone County, TX, Llano County, TX, Marion County, TX, Mason County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Morris County, TX, Navarro County, TX, Rains County, TX, Red River County, TX, Robertson County, TX, Rockwall County, TX, San Saba County, TX, Smith County, TX, Titus County, TX, Travis County, TX, Upshur County, TX, Van Zandt County, TX, Williamson County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 167 km from the middle of the area, began a volume at 20:47 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: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 11, 3:57 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Gillespie, Llano	48 min
May 11, 4:15 PM CDT	Flash Flood Warning	FWD	Hamilton, Mills	2 hr
May 11, 4:22 PM CDT	Severe Thunderstorm Warning	SJT	Mason	53 min
May 11, 4:32 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Burnet, Llano	43 min
May 11, 4:42 PM CDT	Severe Thunderstorm Warning	EWX	Burnet	48 min
May 11, 4:48 PM CDT	Severe Thunderstorm Warning	SHV	McCurtain	42 min
May 11, 4:51 PM CDT	Severe Thunderstorm Warning	FWD	Bell, Coryell, Lampasas	54 min
May 11, 5:12 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Travis, Williamson	48 min
May 11, 5:17 PM CDT	Severe Thunderstorm Warning	SJT	Mason	43 min
May 11, 5:23 PM CDT	Severe Thunderstorm Warning	FWD	Bell, Coryell	52 min
May 11, 5:29 PM CDT	Severe Thunderstorm Warning	SHV	Little River, Sevier	46 min
May 11, 5:29 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Travis, Williamson	46 min
May 11, 5:41 PM CDT	Flash Flood Warning	FWD	Bell, Coryell	2 hr
May 11, 5:50 PM CDT	Severe Thunderstorm Warning	LZK	Polk, Scott	55 min
May 11, 5:58 PM CDT	Severe Thunderstorm Warning	FWD	Falls, McLennan	62 min
May 11, 6:01 PM CDT	Severe Thunderstorm Warning	SJT	Mason	59 min
May 11, 6:28 PM CDT	Severe Thunderstorm Warning	EWX	Llano	47 min
May 11, 6:39 PM CDT	Severe Thunderstorm Warning	LZK	Logan, Montgomery, Pike, Polk, Scott, Yell	48 min
May 11, 6:57 PM CDT	Flash Flood Warning	FWD	Falls, Limestone, McLennan	2 hr
May 11, 7:00 PM CDT	Severe Thunderstorm Warning	SJT	Mason	45 min
May 11, 7:09 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Llano	51 min
May 11, 7:09 PM CDT	Severe Thunderstorm Warning	FWD	Bell, Coryell, McLennan	66 min
May 11, 7:12 PM CDT	Severe Thunderstorm Warning	EWX	Gillespie, Llano	63 min
May 11, 7:18 PM CDT	Flash Flood Warning	SJT	Mason	103 min
May 11, 7:29 PM CDT	Severe Thunderstorm Warning	FWD	Freestone, Limestone, Navarro	61 min
May 11, 7:59 PM CDT	Severe Thunderstorm Warning	EWX	Gillespie, Llano	46 min
May 11, 8:05 PM CDT	Severe Thunderstorm Warning	LZK	Johnson, Newton	43 min
May 11, 8:13 PM CDT	Severe Thunderstorm Warning	FWD	Bell, Coryell, Lampasas, McLennan	62 min
May 11, 8:37 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Burnet, Llano	23 min
May 11, 8:46 PM CDT	Flash Flood Warning	FWD	Bell, Coryell	119 min
May 11, 8:56 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Burnet, Llano, Travis, Williamson	49 min
May 11, 9:33 PM CDT	Severe Thunderstorm Warning	EWX	Burnet, Williamson	27 min
May 11, 9:47 PM CDT	Severe Thunderstorm Warning	FWD	Bell, Milam	58 min
May 11, 9:53 PM CDT	Severe Thunderstorm Warning	EWX	Williamson	37 min
May 11, 10:19 PM CDT	Severe Thunderstorm Warning	EWX	Hays, Travis	41 min
May 11, 10:49 PM CDT	Severe Thunderstorm Warning	EWX	Hays, Travis	41 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, 8.8 hours before the alert went out and 167 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: 1949 J/kg
Mixed-layer CIN: -156 J/kg
Mixed-layer LCL: 622 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 244 m²/s²
0-3 km storm-relative helicity: 274 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 4.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 1:16 PM CDT	Severe Thunderstorm Watch	SPC	Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more	8 hr
May 11, 2:51 PM CDT	Mesoscale Discussion	SPC	Lafayette, Little River, Miller, Sevier	84 min
May 11, 6:35 PM CDT	Mesoscale Discussion	SPC	Benton, Boone, Carroll, Clark, Conway, Crawford and 24 more	55 min
May 11, 2:28 AM CDT	Mesoscale Discussion	SPC	Texas	92 min
May 11, 7:30 AM CDT	Mesoscale Discussion	SPC	Beaver, Beckham, Ellis, Harmon, Harper, Roger Mills	60 min
May 11, 12:33 PM CDT	Mesoscale Discussion	SPC	Atoka, Coal, Creek, Haskell, Hughes, Johnston and 19 more	87 min
May 11, 1:51 PM CDT	Mesoscale Discussion	SPC	Beaver, Harper	84 min
May 11, 6:02 PM CDT	Mesoscale Discussion	SPC	Ellis, Harper, Woods, Woodward	88 min
May 11, 3:29 AM CDT	Severe Thunderstorm Watch	SPC	Andrews, Armstrong, Bailey, Borden, Briscoe, Carson and 46 more	8 hr
May 11, 9:56 AM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coleman, Comanche, Concho and 20 more	94 min
May 11, 10:21 AM CDT	Severe Thunderstorm Watch	SPC	Bell, Bosque, Brown, Burnet, Callahan, Coleman and 52 more	5 hr

Nearby

Severe Thunderstorm Watches in Texas, 2011 Severe Thunderstorm Watches in Arkansas, 2011 Severe Thunderstorm Watches in Oklahoma, 2011 Every severe thunderstorm watch 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.