Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 95

April 14, 202116 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 14, 2021, 1:40 PM CDT for 16 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 14, 2021, 1:40 PM CDT (18:40 UTC)
Expired
Apr 14, 2021, 8:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Aransas County, TX, Bee County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Goliad County, TX, Jackson County, TX, Jefferson County, TX, Matagorda County, TX, Orange County, TX, Refugio County, TX, San Patricio County, TX, Victoria County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 95 km from the middle of the area, began a volume at 18:42 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
2%
Ten or more severe wind reports
30%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 14, 7:52 PM CDTSevere Thunderstorm WarningLCHJefferson38 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

Corpus Christi, TX (KCRP), launched 12:00Z, 6.7 hours before the alert went out and 201 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, Corpus Christi, TX at 12:00Z on 2021-04-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2595 joules per kilogram.LCLLFCEL10008507005003002001001 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, Corpus Christi, TX at 12:00Z on 2021-04-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 square meters per square second.193958Sfc1 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
2595 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
477 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
1.1
Supercell composite
6.0

Open this sounding in Storm Lab

The text

As transmitted.

044 
WWUS20 KWNS 141837
SEL5  
SPC WW 141837
LAZ000-TXZ000-CWZ000-150100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 95
NWS Storm Prediction Center Norman OK
135 PM CDT Wed Apr 14 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Extreme southwest Louisiana
  The Middle and Upper Texas Coastal Plains
  Coastal Waters

* Effective this Wednesday afternoon and evening from 135 PM
  until 800 PM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...Widely scattered thunderstorm development is expected by
mid afternoon from the Middle Texas Coastal Plain northeastward to
extreme southwest Louisiana.  The storm environment will favor a mix
of multicell clusters and some supercell structures, with an
attendant threat for large hail and isolated damaging gusts into
this evening.

The severe thunderstorm watch area is approximately along and 30
statute miles either side of a line from 55 miles southwest of
Victoria TX to 40 miles east of Port Arthur TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU5).

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.

&&

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 550. Mean storm motion vector
27015.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 14, 5:17 AM CDTMesoscale DiscussionSPCAngelina, Hardin, Jasper, Liberty, Montgomery, Nacogdoches and 9 more2 hr
Apr 14, 12:43 PM CDTMesoscale DiscussionSPCBee, Colorado, DeWitt, Fort Bend, Goliad, Gonzales and 8 more2 hr
Apr 14, 4:49 PM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Eastland, Jack and 8 more116 min
Apr 14, 5:27 PM CDTMesoscale DiscussionSPCAransas, Bee, Brazoria, Calhoun, Chambers, DeWitt and 12 more2 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.