Alert archive / Texas / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 37

April 6, 201838 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 6, 2018, 4:00 PM CDT for 38 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 6, 2018, 4:00 PM CDT (21:00 UTC)
Expired
Apr 7, 2018, 12:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 38 counties

Anderson County, TX, Bell County, TX, Bosque County, TX, Collin County, TX, Cooke County, TX, Coryell County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Ellis County, TX, Falls County, TX, Fannin County, TX, Freestone County, TX, Grayson County, TX, Hamilton County, TX, Henderson County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Lampasas County, TX, Leon County, TX, Limestone County, TX, McLennan County, TX, Milam County, TX, Mills County, TX, Navarro County, TX, Parker County, TX, Rains County, TX, Robertson County, TX, Rockwall County, TX, Somervell County, TX, Tarrant County, TX, Van Zandt County, TX, Wise County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 51 km from the middle of the area, began a volume at 21:02 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
60%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 6, 4:08 PM CDTSevere Thunderstorm WarningFWDGrayson67 min
Apr 6, 4:26 PM CDTSevere Thunderstorm WarningFWDLamar35 min
Apr 6, 4:41 PM CDTSevere Thunderstorm WarningFWDCollin, Cooke, Denton, Grayson64 min
Apr 6, 4:54 PM CDTSevere Thunderstorm WarningFWDDallas, Tarrant66 min
Apr 6, 5:07 PM CDTSevere Thunderstorm WarningFWDHopkins42 min
Apr 6, 5:09 PM CDTSevere Thunderstorm WarningFWDParker, Wise41 min
Apr 6, 5:12 PM CDTSevere Thunderstorm WarningFWDFannin, Grayson63 min
Apr 6, 5:23 PM CDTSevere Thunderstorm WarningFWDCollin, Denton67 min
Apr 6, 5:37 PM CDTTornado WarningFWDCollin38 min
Apr 6, 5:58 PM CDTSevere Thunderstorm WarningFWDDallas, Tarrant77 min
Apr 6, 6:13 PM CDTSevere Thunderstorm WarningFWDCollin, Hunt, Kaufman, Rockwall77 min
Apr 6, 6:15 PM CDTSevere Thunderstorm WarningFWDCoryell, Lampasas60 min
Apr 6, 6:27 PM CDTSevere Thunderstorm WarningFWDBosque, Coryell, Hamilton, McLennan63 min
Apr 6, 7:07 PM CDTSevere Thunderstorm WarningFWDDallas, Ellis, Kaufman53 min
Apr 6, 7:11 PM CDTSevere Thunderstorm WarningFWDBell, Coryell, Lampasas, McLennan64 min
Apr 6, 7:28 PM CDTSevere Thunderstorm WarningFWDHunt, Kaufman, Van Zandt62 min
Apr 6, 7:28 PM CDTSevere Thunderstorm WarningFWDBosque, Coryell, Hill, McLennan47 min
Apr 6, 8:00 PM CDTSevere Thunderstorm WarningFWDHenderson, Kaufman, Van Zandt75 min
Apr 6, 8:02 PM CDTSevere Thunderstorm WarningFWDEllis, Hill, McLennan, Navarro58 min
Apr 6, 8:11 PM CDTSevere Thunderstorm WarningFWDBell, Coryell, Falls, McLennan29 min
Apr 6, 8:24 PM CDTSevere Thunderstorm WarningFWDEllis, Navarro51 min
Apr 6, 10:33 PM CDTSevere Thunderstorm WarningFWDBell, Falls, Milam57 min
Apr 6, 11:27 PM CDTSevere Thunderstorm WarningFWDMilam, Robertson35 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, 9.0 hours before the alert went out and 57 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 2018-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 787 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 2018-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 244 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
787 J/kg
Mixed-layer CIN
-166 J/kg
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
244 m²/s²
0-3 km storm-relative helicity
281 m²/s²
Significant tornado parameter
0.3
Supercell composite
3.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 3:20 PM CDTTornado WatchSPCAngelina, Bowie, Camp, Cass, Cherokee, Franklin and 15 more8 hr
Apr 6, 3:40 PM CDTMesoscale DiscussionSPCAnderson, Collin, Dallas, Ellis, Freestone, Henderson and 8 more3 hr
Apr 6, 6:02 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 12 more58 min
Apr 6, 6:45 PM CDTMesoscale DiscussionSPCBell, Bosque, Collin, Coryell, Dallas, Delta and 18 more90 min

Nearby

Severe Thunderstorm Watches in Texas, 2018Every severe thunderstorm watch in 2018

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.