Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 548

November 10, 202121 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Nov 10, 2021, 5:56 PM CST for 21 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Nov 10, 2021, 5:56 PM CST (23:56 UTC)
Expired
Nov 11, 2021, 1:00 AM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 21 counties

Collin County, TX, Cooke County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Fannin County, TX, Grayson County, TX, Henderson County, TX, Hopkins County, TX, Hunt County, TX, Jack County, TX, Kaufman County, TX, Lamar County, TX, Montague County, TX, Navarro County, TX, Rains County, TX, Rockwall County, TX, Tarrant County, TX, Van Zandt County, TX, Wise County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 98 km from the middle of the area, began a volume at 23:58 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
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
50%
One or more hailstones of 2 inches or more
40%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Nov 10, 6:28 PM CSTSevere Thunderstorm WarningFWDCooke, Grayson47 min
Nov 10, 7:01 PM CSTSevere Thunderstorm WarningFWDMontague44 min
Nov 10, 7:14 PM CSTSevere Thunderstorm WarningFWDCollin, Cooke, Denton, Grayson46 min
Nov 10, 7:16 PM CSTSevere Thunderstorm WarningFWDJack, Wise29 min
Nov 10, 7:31 PM CSTSevere Thunderstorm WarningFWDCooke, Jack, Montague, Wise29 min
Nov 10, 7:52 PM CSTSevere Thunderstorm Warning Considerable damage threatFWDCollin, Cooke, Denton, Grayson68 min
Nov 10, 7:56 PM CSTSevere Thunderstorm WarningFWDCooke, Denton, Grayson, Jack, Montague, Wise34 min
Nov 10, 8:23 PM CSTSevere Thunderstorm WarningFWDDenton, Jack, Wise37 min
Nov 10, 8:56 PM CSTSevere Thunderstorm WarningFWDCollin, Dallas, Denton, Hunt, Parker, Rockwall and 2 more64 min
Nov 10, 9:05 PM CSTSevere Thunderstorm WarningFWDLamar40 min
Nov 10, 10:05 PM CSTSevere Thunderstorm WarningFWDDallas40 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, 11.9 hours before the alert went out and 72 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, Fort Worth, TX at 12:00Z on 2021-11-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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, Fort Worth, TX at 12:00Z on 2021-11-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 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
4 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
620 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

908 
WWUS20 KWNS 102353
SEL8  
SPC WW 102353
TXZ000-110700-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 548
NWS Storm Prediction Center Norman OK
555 PM CST Wed Nov 10 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  North-central and northeast Texas

* Effective this Wednesday afternoon and Thursday morning from
  555 PM until 100 AM CST.

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

SUMMARY...Supercells and eventually a growing band of thunderstorms
are expected to move southeastward across the watch area tonight,
with the threat including parts of the DFW Metroplex.  Storms will
offer mainly severe hail and damaging gusts, with a tornado
possible.

The severe thunderstorm watch area is approximately along and 45
statute miles either side of a line from 50 miles north northwest of
Fort Worth TX to 70 miles east of Dallas TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).

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 546...WW 547...

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 450. Mean storm motion vector
30030.

...Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 10, 1:26 PM CSTMesoscale DiscussionSPCCaddo, Canadian, Cleveland, Comanche, Creek, Garfield and 17 more2 hr
Nov 10, 3:26 PM CSTSevere Thunderstorm WatchSPCAdair, Atoka, Bryan, Caddo, Canadian, Carter and 48 more7 hr
Nov 10, 5:06 PM CSTMesoscale DiscussionSPCBryan, Carter, Choctaw, Cotton, Jefferson, Love and 1 more114 min

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.