Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 537

October 26, 202111 counties in Oklahoma; 51 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Oct 26, 2021, 7:23 PM CDT for 11 counties in Oklahoma; 51 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Oct 26, 2021, 7:23 PM CDT (00:23 UTC)
Expired
Oct 27, 2021, 3:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
65 kt
All 62 counties

Caddo County, OK, Comanche County, OK, Cotton County, OK, Grady County, OK, Greer County, OK, Harmon County, OK, Jackson County, OK, Jefferson County, OK, Kiowa County, OK, Stephens County, OK, Tillman County, OK, Archer County, TX, Baylor County, TX, Brown County, TX, Callahan County, TX, Clay County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Cottle County, TX, Crockett County, TX, Dickens County, TX, Eastland County, TX, Erath County, TX, Fisher County, TX, Foard County, TX, Glasscock County, TX, Hardeman County, TX, Haskell County, TX, Irion County, TX, Jack County, TX, Jones County, TX, Kent County, TX, Kimble County, TX, King County, TX, Knox County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Mitchell County, TX, Montague County, TX, Nolan County, TX, Palo Pinto County, TX, Reagan County, TX, Runnels County, TX, San Saba County, TX, Schleicher County, TX, Scurry County, TX, Shackelford County, TX, Stephens County, TX, Sterling County, TX, Stonewall County, TX, Sutton County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Upton County, TX, Wichita County, TX, Wilbarger County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 68 km from the middle of the area, began a volume at 00:23 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
70%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 26, 7:41 PM CDTSevere Thunderstorm WarningLUBGarza, Kent34 min
Oct 26, 7:53 PM CDTSevere Thunderstorm WarningLUBDickens, Kent, King, Stonewall37 min
Oct 26, 8:19 PM CDTSevere Thunderstorm WarningLUBCottle, King56 min
Oct 26, 8:42 PM CDTSevere Thunderstorm Warning Considerable damage threatOUNFoard, Hardeman, Knox78 min
Oct 26, 9:10 PM CDTSevere Thunderstorm Warning Destructive damage threatOUNJackson, Tillman65 min
Oct 26, 9:22 PM CDTSevere Thunderstorm Warning Considerable damage threatOUNHarmon, Jackson, Tillman38 min
Oct 26, 9:59 PM CDTSevere Thunderstorm Warning Considerable damage threatOUNComanche, Greer, Jackson, Kiowa, Tillman46 min
Oct 26, 10:12 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Tillman33 min
Oct 26, 10:33 PM CDTSevere Thunderstorm WarningSJTIrion, Sterling, Tom Green42 min
Oct 26, 10:42 PM CDTSevere Thunderstorm WarningOUNCaddo, Comanche, Cotton, Kiowa, Tillman, Washita63 min
Oct 26, 10:43 PM CDTSevere Thunderstorm WarningSJTCoke, Nolan, Sterling47 min
Oct 26, 11:00 PM CDTSevere Thunderstorm WarningSJTCoke, Irion, Sterling, Tom Green45 min
Oct 26, 11:02 PM CDTSevere Thunderstorm WarningSJTFisher, Jones, Nolan, Taylor43 min
Oct 26, 11:22 PM CDTSevere Thunderstorm Warning Considerable damage threatOUNCaddo, Canadian, Comanche, Garvin, Grady, McClain and 1 more38 min
Oct 26, 11:36 PM CDTSevere Thunderstorm WarningSJTCallahan, Jones, Shackelford, Taylor39 min
Oct 26, 11:44 PM CDTSevere Thunderstorm WarningSJTIrion, Tom Green46 min
Oct 26, 11:50 PM CDTSevere Thunderstorm WarningSJTCallahan, Coleman, Runnels, Taylor, Tom Green55 min
Oct 26, 11:52 PM CDTSevere Thunderstorm Warning Considerable damage threatOUNBlaine, Canadian, Cleveland, Garvin, Grady, Kingfisher and 3 more53 min
Oct 26, 11:52 PM CDTSevere Thunderstorm WarningSJTJones, Shackelford53 min
Oct 27, 12:17 AM CDTSevere Thunderstorm WarningSJTCallahan, Jones, Shackelford, Taylor58 min
Oct 27, 1:07 AM CDTSevere Thunderstorm WarningFWDJack, Palo Pinto, Stephens, Young53 min
Oct 27, 1:44 AM CDTSevere Thunderstorm WarningFWDJack, Palo Pinto, Parker, Wise61 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

Midland Regional, TX (KMAF), launched 00:00Z, 0.4 hours before the alert went out and 217 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-pSkew-T log-p diagram, Midland Regional, TX at 00:00Z on 2021-10-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Midland Regional, TX at 00:00Z on 2021-10-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
4696 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
98 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

757 
WWUS20 KWNS 270021
SEL7  
SPC WW 270021
OKZ000-TXZ000-270800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 537
NWS Storm Prediction Center Norman OK
725 PM CDT Tue Oct 26 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Southwest Oklahoma
  West Central Texas

* Effective this Tuesday night and Wednesday morning from 725 PM
  until 300 AM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter likely
  Scattered damaging winds likely with isolated significant gusts
    to 75 mph possible
  A tornado or two possible

SUMMARY...Thunderstorms are expected to develop along the dryline
over west Texas this evening and spread eastward across the watch
area.  The primary threat will be damaging winds and large hail in
the most intense cells, although an isolated tornado or two cannot
be ruled out.

The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 45 miles west of Junction
TX to 40 miles west northwest of Chickasha OK. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU7).

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 536...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
24025.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 26, 8:59 PM CDTMesoscale DiscussionSPCAlfalfa, Blaine, Custer, Dewey, Ellis, Harper and 4 more91 min
Oct 26, 9:37 PM CDTMesoscale DiscussionSPCBeckham, Caddo, Comanche, Cotton, Grady, Greer and 5 more83 min
Oct 26, 10:09 PM CDTMesoscale DiscussionSPCAtoka, Bryan, Carter, Cleveland, Coal, Creek and 31 more66 min
Oct 26, 10:26 PM CDTSevere Thunderstorm WatchSPCAtoka, Bryan, Canadian, Carter, Cleveland, Coal and 26 more7 hr
Oct 27, 1:13 AM CDTMesoscale DiscussionSPCAtoka, Bryan, Coal, Creek, Hughes, Johnston and 15 more2 hr
Oct 27, 1:32 AM CDTSevere Thunderstorm WatchSPCAnderson, Bastrop, Bell, Bexar, Blanco, Bosque and 48 more6 hr
Oct 27, 1:59 AM CDTMesoscale DiscussionSPCCollin, Cooke, Dallas, Denton, Ellis, Grayson and 8 more91 min
Oct 27, 5:13 AM CDTMesoscale DiscussionSPCAtascosa, Austin, Bastrop, Bexar, Brazos, Burleson and 22 more2 hr
Oct 27, 7:36 AM CDTMesoscale DiscussionSPCChambers, Hardin, Jasper, Jefferson, Newton, Orange and 1 more84 min
Oct 27, 7:55 AM CDTTornado WatchSPCAngelina, Brazoria, Chambers, Fort Bend, Galveston, Hardin and 16 more9 hr
Oct 27, 9:08 AM CDTMesoscale DiscussionSPCHardin, Jasper, Jefferson, Newton, Orange, Tyler97 min
Oct 27, 9:44 AM CDTMesoscale DiscussionSPCBowie, Cass, Harrison, Marion, Panola, Shelby2 hr
Oct 27, 10:08 AM CDTTornado WatchSPCHarrison, Marion, Panola, Shelby5 hr
Oct 27, 10:59 AM CDTMesoscale DiscussionSPCNewton91 min
Oct 27, 12:52 PM CDTMesoscale DiscussionSPCBowie, Cass, Harrison, Marion, Panola, Shelby83 min

Nearby

Severe Thunderstorm Watches in Texas, 2021Severe Thunderstorm Watches in Oklahoma, 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.