Alert archive / Texas / Tornado Watches in 2020

Tornado Watch 55

March 18, 202040 counties in Texas

The Storm Prediction Center issued this tornado watch at Mar 18, 2020, 11:37 PM CDT for 40 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2020, 11:37 PM CDT (04:37 UTC)
Expired
Mar 19, 2020, 5:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 40 counties

Brown County, TX, Callahan County, TX, Coke County, TX, Coleman County, TX, Comanche County, TX, Concho County, TX, Crockett County, TX, Eastland County, TX, Edwards County, TX, Fisher County, TX, Gillespie County, TX, Haskell County, TX, Irion County, TX, Jack County, TX, Jones County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Nolan County, TX, Palo Pinto County, TX, Real County, TX, Runnels County, TX, San Saba County, TX, Schleicher County, TX, Shackelford County, TX, Stephens County, TX, Sterling County, TX, Sutton County, TX, Taylor County, TX, Throckmorton County, TX, Tom Green County, TX, Uvalde County, TX, Val Verde County, TX, Wise County, TX, Young County, TX

The radar

The Dyess AFB radar (KDYX), 87 km from the middle of the area, began a volume at 04:40 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
60%
One or more EF2 to EF5 tornadoes
40%
Ten or more severe wind reports
60%
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
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 18, 11:54 PM CDTTornado Warning Considerable damage threatSJTCoke, Sterling34 min
Mar 19, 12:22 AM CDTTornado WarningSJTNolan38 min
Mar 19, 12:56 AM CDTTornado WarningSJTNolan, Taylor34 min
Mar 19, 1:17 AM CDTTornado WarningSJTCallahan, Jones, Shackelford, Taylor43 min
Mar 19, 1:49 AM CDTTornado Warning Considerable damage threatSJTShackelford, Throckmorton41 min
Mar 19, 2:01 AM CDTSevere Thunderstorm WarningEWXVal Verde44 min
Mar 19, 2:27 AM CDTTornado WarningSJTShackelford18 min
Mar 19, 2:29 AM CDTSevere Thunderstorm WarningFWDStephens, Young61 min
Mar 19, 2:32 AM CDTSevere Thunderstorm WarningEWXEdwards, Kinney, Val Verde58 min
Mar 19, 2:32 AM CDTTornado WarningFWDStephens28 min
Mar 19, 2:54 AM CDTTornado WarningFWDStephens, Young36 min
Mar 19, 3:13 AM CDTSevere Thunderstorm WarningEWXEdwards, Kerr, Real62 min
Mar 19, 3:17 AM CDTTornado WarningFWDJack, Young43 min
Mar 19, 4:13 AM CDTSevere Thunderstorm WarningEWXGillespie, Kerr62 min
Mar 19, 4:18 AM CDTSevere Thunderstorm WarningSJTKimble20 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 00:00Z, 4.6 hours before the alert went out and 242 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 00:00Z on 2020-03-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1265 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2020-03-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 square meters per square second.19395878Sfc1 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
1265 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
888 m above ground
0-6 km bulk shear
58 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
237 m²/s²
Significant tornado parameter
1.9
Supercell composite
11.8

Open this sounding in Storm Lab

The text

As transmitted.

564 
WWUS20 KWNS 190434
SEL5  
SPC WW 190434
TXZ000-191000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 55
NWS Storm Prediction Center Norman OK
1140 PM CDT Wed Mar 18 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  West Central Texas

* Effective this Wednesday night and Thursday morning from 1140
  PM until 500 AM CDT.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Scattered damaging wind gusts to 70 mph likely
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible

SUMMARY...A cluster of intense thunderstorms will spread across the
watch area overnight, with large hail and damaging winds possible. 
A few of the storms may also pose a risk of a tornado or two.

The tornado watch area is approximately along and 85 statute miles
east and west of a line from 50 miles north of Abilene TX to 55
miles south southwest of Junction TX. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 54...

AVIATION...Tornadoes and 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 450. Mean
storm motion vector 24035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 18, 8:45 PM CDTMesoscale DiscussionSPCBandera, Coke, Concho, Crockett, Edwards, Irion and 18 more60 min
Mar 18, 9:34 PM CDTMesoscale DiscussionSPCCooke, Grayson, Wise56 min
Mar 19, 1:28 AM CDTMesoscale DiscussionSPCBrown, Callahan, Coke, Coleman, Comanche, Concho and 23 more2 hr
Mar 19, 2:08 AM CDTMesoscale DiscussionSPCShackelford, Stephens67 min
Mar 19, 3:33 AM CDTMesoscale DiscussionSPCBandera, Brown, Callahan, Coleman, Comanche, Concho and 24 more117 min
Mar 19, 1:58 PM CDTMesoscale DiscussionSPCBosque, Bowie, Camp, Collin, Dallas, Delta and 26 more62 min
Mar 19, 2:24 PM CDTTornado WatchSPCBowie, Camp, Cass, Collin, Delta, Fannin and 18 more8 hr
Mar 19, 6:51 PM CDTMesoscale DiscussionSPCBell, Bosque, Coryell, Falls, Freestone, Hamilton and 9 more54 min

Nearby

Tornado Watches in Texas, 2020Every tornado watch in 2020

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.