Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 102

April 23, 20214 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 23, 2021, 7:42 PM CDT for 4 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 23, 2021, 7:42 PM CDT (00:42 UTC)
Expired: Apr 23, 2021, 10:10 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2.5 in
Strongest gust expected: 60 kt

Counties Bee County, TX, Goliad County, TX, Live Oak County, TX, Victoria County, TX

The radar

The Corpus Christi radar (KCRP), 99 km from the middle of the area, began a volume at 00:42 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: 5%
Ten or more severe wind reports: 20%
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: 40%
Six or more combined severe hail and wind reports: 60%

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
Apr 23, 8:00 PM CDT	Severe Thunderstorm Warning	CRP	Bee, Live Oak	30 min
Apr 23, 8:28 PM CDT	Severe Thunderstorm Warning	CRP	Bee, Goliad	32 min
Apr 23, 8:59 PM CDT	Severe Thunderstorm Warning	CRP	Bee, Goliad, Refugio	31 min

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 0.7 hours before the alert went out and 107 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: 1602 J/kg
Mixed-layer CIN: -138 J/kg
Mixed-layer LCL: 883 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 44 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

188 
WWUS20 KWNS 240039
SEL2  
SPC WW 240039
TXZ000-240400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 102
NWS Storm Prediction Center Norman OK
740 PM CDT Fri Apr 23 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  A small part of the middle Texas coastal plain

* Effective this Friday evening from 740 PM until 1100 PM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...A supercell may persist for a few hours while moving a
little south of east, with an accompanying threat for isolated very
large hail and damaging winds.

The severe thunderstorm watch area is approximately along and 25
statute miles north and south of a line from 30 miles west of
Beeville TX to 20 miles east northeast of Victoria 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 98...WW 99...WW 100...WW
101...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 600. Mean storm motion vector
28025.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 23, 7:05 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bexar, DeWitt, Fayette, Gonzales, Guadalupe and 3 more	3 hr
Apr 23, 7:43 PM CDT	Mesoscale Discussion	SPC	Clay, Cooke, Grayson, Hardeman, Montague, Wichita and 1 more	2 hr
Apr 23, 8:02 PM CDT	Severe Thunderstorm Watch	SPC	Archer, Clay, Cooke, Denton, Grayson, Jack and 3 more	4 hr
Apr 23, 11:19 PM CDT	Mesoscale Discussion	SPC	Camp, Delta, Fannin, Franklin, Hopkins, Lamar and 2 more	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.