Alert archive / Texas / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 232, NWS San Angelo, TX

September 20, 2017Callahan County, Shackelford County, Texas

NWS San Angelo, TX issued this severe thunderstorm warning at Sep 20, 2017, 8:57 PM CDT for Callahan County, Shackelford County, Texas. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 20, 2017, 8:57 PM CDT (01:57 UTC)
Expired
Sep 20, 2017, 9:45 PM CDT
In force
48 min
Issued by
NWS San Angelo, TX
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Callahan County, TX, Shackelford County, TX

The radar

The Dyess AFB radar (KDYX), 11 km from the middle of the area, began a volume at 01:58 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.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 2.0 hours before the alert went out and 197 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 2017-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2825 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 00:00Z on 2017-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.1939Sfc1 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
2825 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
1820 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
116 m²/s²
Significant tornado parameter
0.0
Supercell composite
5.7

Open this sounding in Storm Lab

The office that day

Everything else NWS San Angelo, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 20, 7:00 PM CDTAreal Flood AdvisorySJTIrion, Tom Green3 hr
Sep 20, 7:04 PM CDTSevere Thunderstorm WarningSJTIrion41 min
Sep 20, 7:14 PM CDTSpecial Weather StatementSJTTaylor46 min
Sep 20, 7:24 PM CDTSevere Thunderstorm WarningSJTCallahan, Runnels, Taylor51 min
Sep 20, 8:13 PM CDTSevere Thunderstorm WarningSJTCallahan, Coleman, Runnels, Taylor32 min
Sep 20, 8:48 PM CDTSpecial Weather StatementSJTCallahan42 min

Nearby

Severe Thunderstorm Warnings in Texas, 2017Every severe thunderstorm warning 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.