Alert archive / Texas / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 166
The Storm Prediction Center issued this severe thunderstorm watch at May 11, 2021, 5:22 PM CDT for Allen Parish, Beauregard Parish, Vernon Parish, Louisiana; 4 counties in Texas. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- May 11, 2021, 5:22 PM CDT (22:22 UTC)
- Expired
- May 11, 2021, 9:26 PM CDT
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
Counties Allen Parish, LA, Beauregard Parish, LA, Vernon Parish, LA, Hardin County, TX, Jasper County, TX, Newton County, TX, Tyler County, TX
The radar
The Ft Polk radar (KPOE), 98 km from the middle of the area, began a volume at 22:24 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
- 50%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 5:58 PM CDT | Severe Thunderstorm Warning | LCH | Jasper, Tyler | 62 min |
| May 11, 6:27 PM CDT | Severe Thunderstorm Warning | LCH | Hardin | 63 min |
| May 11, 6:54 PM CDT | Severe Thunderstorm Warning | LCH | Jasper, Newton, Tyler | 25 min |
| May 11, 7:07 PM CDT | Severe Thunderstorm Warning | LCH | Jasper, Tyler | 27 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
Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.4 hours before the alert went out and 129 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
- 2925 J/kg
- Mixed-layer CIN
- -9 J/kg
- Mixed-layer LCL
- 472 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 87 m²/s²
- 0-3 km storm-relative helicity
- 155 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 11.9
The text
As transmitted.
492 WWUS20 KWNS 112219 SEL6 SPC WW 112219 LAZ000-TXZ000-120400- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 166 NWS Storm Prediction Center Norman OK 520 PM CDT Tue May 11 2021 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western Louisiana East Texas * Effective this Tuesday afternoon and evening from 520 PM until 1100 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...A cluster of thunderstorms over east Texas is expected to persist for several hours and track along a warm front into western Louisiana. Winds aloft have strengthened somewhat, suggesting a risk of locally damaging wind gusts or perhaps a tornado or two through the evening. The severe thunderstorm watch area is approximately along and 30 statute miles north and south of a line from 90 miles west of Fort Polk LA to 20 miles southeast of Fort Polk LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 164...WW 165... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27030. ...Hart
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 4:37 PM CDT | Mesoscale Discussion | SPC | Beauregard, Calcasieu | 83 min |
| May 11, 6:36 PM CDT | Mesoscale Discussion | SPC | Beauregard, Vernon | 84 min |
| May 10, 8:01 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bexar, Dimmit, Frio, Kendall, Medina and 1 more | 119 min |
| May 11, 4:44 AM CDT | Mesoscale Discussion | SPC | Andrews, Borden, Coke, Crane, Crosby, Dawson and 26 more | 2 hr |
| May 11, 10:13 AM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Bosque, Brown, Burnet, Callahan and 45 more | 62 min |
| May 11, 1:22 PM CDT | Mesoscale Discussion | SPC | Dimmit, Kinney, Maverick, Terrell, Val Verde, Zavala | 2 hr |
| May 11, 1:59 PM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Burleson, Burnet, Cherokee, Coryell and 18 more | 2 hr |
| May 11, 3:04 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Angelina, Brazos, Burleson, Cherokee, Freestone and 17 more | 4 hr |
| May 11, 3:41 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 29 more | 10 hr |
| May 11, 5:23 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bee, Colorado, DeWitt, Goliad, Gonzales and 11 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Texas, 2021Severe Thunderstorm Watches in Louisiana, 2021Every severe thunderstorm watch in 2021
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.