Alert archive / Texas / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 36

February 19, 201710 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Feb 19, 2017, 8:36 PM CST for 10 counties in Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Feb 19, 2017, 8:36 PM CST (02:36 UTC)
Expired
Feb 20, 2017, 1:00 AM CST
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt

Counties Brooks County, TX, Duval County, TX, Jim Hogg County, TX, Jim Wells County, TX, La Salle County, TX, Live Oak County, TX, McMullen County, TX, Starr County, TX, Webb County, TX, Zapata County, TX

The radar

The Corpus Christi radar (KCRP), 147 km from the middle of the area, began a volume at 02:39 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
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
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.

IssuedProductOfficeCountiesLasted
Feb 19, 8:44 PM CSTFlash Flood WarningCRPWebb3 hr
Feb 19, 8:49 PM CSTSevere Thunderstorm WarningCRPDuval, Webb30 min
Feb 19, 8:56 PM CSTTornado WarningCRPDuval, Webb18 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 00:00Z, 2.6 hours before the alert went out and 164 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 00:00Z on 2017-02-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1800 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 00:00Z on 2017-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 178 square meters per square second.1939587897Sfc1 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
1800 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
663 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
178 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.4
Supercell composite
9.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 19, 6:18 PM CSTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bexar, Caldwell, Comal and 20 more8 hr
Feb 19, 6:43 PM CSTMesoscale DiscussionSPCArcher, Baylor, Brown, Callahan, Clay, Coleman and 26 more2 hr
Feb 19, 8:13 PM CSTMesoscale DiscussionSPCBandera, Dimmit, Edwards, Kerr, Kinney, Maverick and 3 more2 hr
Feb 19, 8:33 PM CSTMesoscale DiscussionSPCBosque, Comanche, Cooke, Coryell, Denton, Erath and 15 more117 min
Feb 19, 10:28 PM CSTMesoscale DiscussionSPCAtascosa, Bexar, Comal, Kendall, McMullen, Wilson92 min
Feb 19, 11:50 PM CSTMesoscale DiscussionSPCBastrop, Brazos, Burleson, Falls, Fayette, Grimes and 4 more85 min
Feb 20, 1:56 AM CSTMesoscale DiscussionSPCBrazos, Houston, Leon, Madison, Trinity, Walker3 hr
Feb 20, 4:32 AM CSTMesoscale DiscussionSPCAransas, Calhoun, Cameron, Kenedy, Kleberg, Nueces and 1 more3 hr

Nearby

Severe Thunderstorm Watches in Texas, 2017Every severe thunderstorm watch in 2017

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.