Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 230

May 31, 202119 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 31, 2021, 2:54 PM CDT for 19 counties in Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: May 31, 2021, 2:54 PM CDT (19:54 UTC)
Expired: May 31, 2021, 7:00 PM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

Counties Bell County, TX, Bosque County, TX, Comanche County, TX, Coryell County, TX, Ellis County, TX, Erath County, TX, Falls County, TX, Hamilton County, TX, Hill County, TX, Hood County, TX, Johnson County, TX, Lampasas County, TX, Limestone County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Navarro County, TX, Robertson County, TX, Somervell County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 86 km from the middle of the area, began a volume at 19:57 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: 10%
One or more EF2 to EF5 tornadoes: 2%
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: 30%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 31, 3:04 PM CDT	Severe Thunderstorm Warning	FWD	Comanche, Erath	26 min
May 31, 3:28 PM CDT	Severe Thunderstorm Warning	FWD	Bosque, Erath, Hamilton, Hood, Somervell	62 min
May 31, 4:25 PM CDT	Severe Thunderstorm Warning	FWD	Bosque, Hill, Hood, Johnson, Somervell	65 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, 7.9 hours before the alert went out and 113 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 10 J/kg
Mixed-layer CIN: -109 J/kg
Mixed-layer LCL: 647 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 212 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

927 
WWUS20 KWNS 311948
SEL0  
SPC WW 311948
TXZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 230
NWS Storm Prediction Center Norman OK
250 PM CDT Mon May 31 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Central Texas

* Effective this Monday afternoon and evening from 250 PM until
  700 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 70 mph possible

SUMMARY...A line of thunderstorms has recently intensified, and will
track southeastward across the watch area this afternoon.  Locally
damaging wind gusts are the main threat, although hail and an
isolated tornado or two cannot be ruled out.

The severe thunderstorm watch area is approximately along and 50
statute miles north and south of a line from 35 miles south
southwest of Stephenville TX to 50 miles east of Waco TX. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).

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 229...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 8:59 PM CDT	Mesoscale Discussion	SPC	Carson, Gray, Hansford, Hemphill, Hutchinson, Lipscomb and 6 more	91 min
May 30, 9:17 PM CDT	Severe Thunderstorm Watch	SPC	Armstrong, Carson, Collingsworth, Donley, Gray, Hemphill and 4 more	5 hr
May 30, 9:22 PM CDT	Mesoscale Discussion	SPC	Andrews, Borden, Cochran, Cottle, Crosby, Dawson and 20 more	83 min
May 30, 11:43 PM CDT	Mesoscale Discussion	SPC	Bailey, Cochran, Cottle, Crosby, Dickens, Floyd and 12 more	92 min
May 31, 2:12 AM CDT	Mesoscale Discussion	SPC	Borden, Fisher, Haskell, Howard, Jones, Kent and 5 more	3 hr
May 31, 11:33 AM CDT	Mesoscale Discussion	SPC	Andrews, Borden, Brewster, Cochran, Crane, Crockett and 26 more	87 min
May 31, 12:16 PM CDT	Severe Thunderstorm Watch	SPC	Andrews, Coke, Crane, Crockett, Culberson, Ector and 21 more	9 hr
May 31, 2:15 PM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coleman, Comanche, Coryell and 10 more	2 hr
May 31, 3:29 PM CDT	Mesoscale Discussion	SPC	Andrews, Coke, Crane, Crockett, Culberson, Ector and 21 more	91 min
May 31, 5:12 PM CDT	Mesoscale Discussion	SPC	Bell, Bosque, Coryell, Ellis, Falls, Freestone and 10 more	93 min
May 31, 5:49 PM CDT	Mesoscale Discussion	SPC	Brewster, Pecos, Terrell	116 min

Nearby

Severe Thunderstorm Watches in Texas, 2021 Every 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.