Alert archive / Texas / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 339
The Storm Prediction Center issued this severe thunderstorm watch at May 23, 2011, 9:59 AM CDT for 35 counties in Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- May 23, 2011, 9:59 AM CDT (14:59 UTC)
- Expired
- May 23, 2011, 3:43 PM CDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2.5 in
- Strongest gust expected
- 60 kt
All 35 counties
Bosque County, TX, Collin County, TX, Comanche County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Eastland County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Grayson County, TX, Hamilton County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Mills County, TX, Montague County, TX, Navarro County, TX, Palo Pinto County, TX, Parker County, TX, Rains County, TX, Rockwall County, TX, Somervell County, TX, Stephens County, TX, Tarrant County, TX, Van Zandt County, TX, Wise County, TX, Young County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 45 km from the middle of the area, began a volume at 14:58 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
- 40%
- One or more hailstones of 2 inches or more
- 60%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 10:21 AM CDT | Severe Thunderstorm Warning | FWD | Tarrant | 54 min |
| May 23, 10:23 AM CDT | Severe Thunderstorm Warning | FWD | Parker | 45 min |
| May 23, 10:45 AM CDT | Severe Thunderstorm Warning | FWD | Dallas | 75 min |
| May 23, 10:56 AM CDT | Severe Thunderstorm Warning | FWD | Denton | 79 min |
| May 23, 11:11 AM CDT | Severe Thunderstorm Warning | FWD | Tarrant | 64 min |
| May 23, 11:29 AM CDT | Severe Thunderstorm Warning | FWD | Kaufman, Rockwall | 48 min |
| May 23, 11:47 AM CDT | Severe Thunderstorm Warning | FWD | Collin | 58 min |
| May 23, 11:53 AM CDT | Severe Thunderstorm Warning | FWD | Dallas | 67 min |
| May 23, 12:38 PM CDT | Severe Thunderstorm Warning | FWD | Collin, Denton | 67 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, 3.0 hours before the alert went out and 26 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.
- Mixed-layer CAPE
- 2692 J/kg
- Mixed-layer CIN
- -168 J/kg
- Mixed-layer LCL
- 610 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 387 m²/s²
- 0-3 km storm-relative helicity
- 362 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 15.4
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 22, 8:10 PM CDT | Mesoscale Discussion | SPC | Bosque, Brown, Callahan, Clay, Collin, Comanche and 34 more | 65 min |
| May 22, 8:59 PM CDT | Severe Thunderstorm Watch | SPC | Bell, Bosque, Collin, Comanche, Coryell, Dallas and 28 more | 2 hr |
| May 23, 9:57 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Collin, Dallas, Delta and 30 more | 33 min |
| May 23, 12:10 PM CDT | Mesoscale Discussion | SPC | Anderson, Bosque, Bowie, Camp, Cass, Cherokee and 46 more | 65 min |
| May 23, 2:08 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Childress, Cottle, Foard, Hardeman and 11 more | 97 min |
| May 23, 2:30 PM CDT | Tornado Watch | SPC | Archer, Baylor, Clay, Foard, Hardeman, Knox and 2 more | 8 hr |
| May 23, 4:58 PM CDT | Mesoscale Discussion | SPC | Brown, Callahan, Coleman, Eastland, Shackelford, Stephens and 2 more | 62 min |
| May 23, 6:51 PM CDT | Mesoscale Discussion | SPC | Archer, Clay, Wichita | 84 min |
Nearby
Severe Thunderstorm Watches in Texas, 2011Every 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.