Alert archive / Texas / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 90
The Storm Prediction Center issued this severe thunderstorm watch at Apr 4, 2011, 7:44 AM CDT for 17 parishes in Louisiana; 54 counties in Texas. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 4, 2011, 7:44 AM CDT (12:44 UTC)
- Expired
- Apr 4, 2011, 4:00 PM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 70 kt
All 71 counties
Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Anderson County, TX, Angelina County, TX, Bastrop County, TX, Bell County, TX, Bowie County, TX, Brazos County, TX, Burleson County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Coryell County, TX, Falls County, TX, Franklin County, TX, Freestone County, TX, Gregg County, TX, Grimes County, TX, Harrison County, TX, Hays County, TX, Henderson County, TX, Hill County, TX, Hopkins County, TX, Houston County, TX, Kaufman County, TX, Lee County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Marion County, TX, McLennan County, TX, Milam County, TX, Montgomery County, TX, Morris County, TX, Nacogdoches County, TX, Navarro County, TX, Panola County, TX, Polk County, TX, Rains County, TX, Red River County, TX, Robertson County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Travis County, TX, Trinity County, TX, Upshur County, TX, Van Zandt County, TX, Walker County, TX, Washington County, TX, Williamson County, TX, Wood County, TX
The radar
The Shreveport radar (KSHV), 171 km from the middle of the area, began a volume at 12:45 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
- 10%
- Ten or more severe wind reports
- 60%
- 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
- 10%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 4, 7:53 AM CDT | Severe Thunderstorm Warning | EWX | Bastrop, Lee, Travis, Williamson | 52 min |
| Apr 4, 7:53 AM CDT | Severe Thunderstorm Warning | FWD | Anderson, Henderson | 52 min |
| Apr 4, 7:56 AM CDT | Severe Thunderstorm Warning | SHV | Bowie, Camp, Cass, Marion, Morris, Red River and 2 more | 64 min |
| Apr 4, 7:58 AM CDT | Severe Thunderstorm Warning | FWD | Milam | 47 min |
| Apr 4, 8:01 AM CDT | Severe Thunderstorm Warning | FWD | Anderson, Freestone, Leon, Limestone | 59 min |
| Apr 4, 8:17 AM CDT | Severe Thunderstorm Warning | SHV | Camp, Franklin, Morris, Smith, Titus, Upshur and 1 more | 58 min |
| Apr 4, 8:19 AM CDT | Severe Thunderstorm Warning | SHV | Bowie | 56 min |
| Apr 4, 8:26 AM CDT | Severe Thunderstorm Warning | FWD | Leon, Robertson | 64 min |
| Apr 4, 8:29 AM CDT | Severe Thunderstorm Warning | SHV | Bossier, Caddo | 61 min |
| Apr 4, 8:30 AM CDT | Severe Thunderstorm Warning | FWD | Robertson | 43 min |
| Apr 4, 8:42 AM CDT | Tornado Warning | SHV | Cass | 48 min |
| Apr 4, 9:08 AM CDT | Severe Thunderstorm Warning | HGX | Houston | 52 min |
| Apr 4, 9:21 AM CDT | Severe Thunderstorm Warning | SHV | Bossier, Caddo, Webster | 54 min |
| Apr 4, 9:33 AM CDT | Severe Thunderstorm Warning | SHV | Bossier, Caddo, De Soto | 57 min |
| Apr 4, 9:46 AM CDT | Severe Thunderstorm Warning | SHV | Claiborne, Webster | 59 min |
| Apr 4, 10:52 AM CDT | Severe Thunderstorm Warning | HGX | Austin, Grimes, Harris, Montgomery, Walker, Waller and 1 more | 16 min |
| Apr 4, 12:17 PM CDT | Severe Thunderstorm Warning | SHV | Grant, Jackson, Natchitoches, Winn | 43 min |
| Apr 4, 1:24 PM CDT | Severe Thunderstorm Warning | SHV | Grant, Jackson, LaSalle, Natchitoches, Winn | 51 min |
| Apr 4, 2:11 PM CDT | Severe Thunderstorm Warning | SHV | Caldwell, Grant, Jackson, LaSalle, Winn | 49 min |
| Apr 4, 2:39 PM CDT | Tornado Warning | SHV | Caldwell, Grant, LaSalle, Winn | 36 min |
| Apr 4, 2:49 PM CDT | Severe Thunderstorm Warning | SHV | Caldwell, Ouachita | 26 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
Shreveport, LA (KSHV), launched 12:00Z, 0.7 hours before the alert went out and 180 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
- 1653 J/kg
- Mixed-layer CIN
- -35 J/kg
- Mixed-layer LCL
- 738 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 196 m²/s²
- 0-3 km storm-relative helicity
- 292 m²/s²
- Significant tornado parameter
- 1.6
- Supercell composite
- 8.2
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 4, 10:25 AM CDT | Mesoscale Discussion | SPC | East Carroll, Morehouse, West Carroll | 2 hr |
| Apr 4, 10:53 AM CDT | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more | 7 hr |
| Apr 4, 11:20 AM CDT | Mesoscale Discussion | SPC | Beauregard, Bienville, Caldwell, Claiborne, De Soto, Grant and 12 more | 115 min |
| Apr 4, 2:52 PM CDT | Mesoscale Discussion | SPC | Avoyelles, Caldwell, Catahoula, Concordia, Franklin, LaSalle and 4 more | 113 min |
| Apr 4, 4:28 PM CDT | Mesoscale Discussion | SPC | Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 2 more | 62 min |
| Apr 4, 5:28 PM CDT | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 18 more | 7 hr |
| Apr 4, 6:50 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, Iberia, Jefferson, Lafourche, Livingston and 10 more | 85 min |
| Apr 4, 3:00 AM CDT | Mesoscale Discussion | SPC | Bosque, Bowie, Brown, Callahan, Camp, Cass and 42 more | 3 hr |
| Apr 4, 3:44 AM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more | 7 hr |
| Apr 4, 5:48 AM CDT | Mesoscale Discussion | SPC | Anderson, Bosque, Bowie, Camp, Cass, Collin and 33 more | 117 min |
Nearby
Severe Thunderstorm Watches in Texas, 2011Severe Thunderstorm Watches in Louisiana, 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.