Alert archive / Texas / Severe Thunderstorm Watches in 2021
Severe Thunderstorm Watch 142
The Storm Prediction Center issued this severe thunderstorm watch at May 4, 2021, 8:11 AM CDT for 28 counties in Texas. It was in force for 8 hr.
The area
The outline as issued.
The facts
- Issued
- May 4, 2021, 8:11 AM CDT (13:11 UTC)
- Expired
- May 4, 2021, 3:45 PM CDT
- In force
- 8 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 55 kt
All 28 counties
Angelina County, TX, Austin County, TX, Brazos County, TX, Burleson County, TX, Chambers County, TX, Colorado County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Madison County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX, Waller County, TX, Washington County, TX
The radar
The Houston radar (KHGX), 134 km from the middle of the area, began a volume at 13:13 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
- 2%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 8:17 AM CDT | Severe Thunderstorm Warning | HGX | Brazos, Burleson | 28 min |
| May 4, 8:57 AM CDT | Severe Thunderstorm Warning | HGX | Brazos, Burleson, Grimes, Waller, Washington | 48 min |
| May 4, 11:07 AM CDT | Severe Thunderstorm Warning | SHV | Panola, Shelby | 38 min |
| May 4, 11:52 AM CDT | Tornado Warning | LCH | Newton | 23 min |
| May 4, 1:14 PM CDT | Severe Thunderstorm Warning | HGX | Liberty | 31 min |
| May 4, 2:09 PM CDT | Severe Thunderstorm Warning | LCH | Hardin, Jasper | 36 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, 1.2 hours before the alert went out and 231 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
- 3311 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 458 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 57 m²/s²
- 0-3 km storm-relative helicity
- 144 m²/s²
- Significant tornado parameter
- 1.2
- Supercell composite
- 6.6
The text
As transmitted.
912
WWUS20 KWNS 041309
SEL2
SPC WW 041309
TXZ000-CWZ000-041800-
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 142
NWS Storm Prediction Center Norman OK
810 AM CDT Tue May 4 2021
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
East/Southeast Texas
Coastal Waters
* Effective this Tuesday morning and afternoon from 810 AM until
100 PM CDT.
* Primary threats include...
Scattered large hail and isolated very large hail events to 2
inches in diameter possible
Scattered damaging wind gusts to 65 mph possible
A tornado or two possible
SUMMARY...Severe thunderstorms are expected to increase in coverage
and intensity across portions of East/Southeast Texas through the
morning, with severe hail and isolated damaging winds as the primary
hazards.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 40 miles southwest of
College Station TX to 65 miles north northeast of Port Arthur TX.
For a complete depiction of the watch see the associated watch
outline update (WOUS64 KWNS WOU2).
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 141...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 55 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
25025.
...GuyerSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 7:01 PM CDT | Severe Thunderstorm Watch | SPC | Atascosa, Bandera, Bexar, Blanco, Burnet, Comal and 9 more | 4 hr |
| May 3, 7:38 PM CDT | Mesoscale Discussion | SPC | Bosque, Collin, Dallas, Denton, Ellis, Fannin and 6 more | 97 min |
| May 3, 8:30 PM CDT | Mesoscale Discussion | SPC | Bexar, Blanco, Comal, Guadalupe, Hays, Kendall | 60 min |
| May 3, 8:38 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Gregg, Marion, Morris and 4 more | 2 hr |
| May 3, 9:10 PM CDT | Mesoscale Discussion | SPC | Callahan, Eastland, Fisher, Haskell, Jones, Nolan and 6 more | 95 min |
| May 3, 9:10 PM CDT | Severe Thunderstorm Watch | SPC | Bowie, Camp, Cass, Cherokee, Franklin, Gregg and 10 more | 7 hr |
| May 3, 9:52 PM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Coryell, Ellis, Falls, Freestone and 12 more | 53 min |
| May 3, 10:22 PM CDT | Severe Thunderstorm Watch | SPC | Anderson, Bell, Collin, Cooke, Dallas, Delta and 28 more | 5 hr |
| May 3, 11:34 PM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Falls, Franklin, Freestone and 12 more | 86 min |
| May 4, 6:44 AM CDT | Mesoscale Discussion | SPC | Anderson, Bell, Brazos, Burleson, Camp, Cass and 23 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Texas, 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.