Alert archive / Texas / Mesoscale Discussions in 2023

Mesoscale Discussion 2139

September 11, 202320 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 11, 2023, 11:29 PM CDT for 20 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 11, 2023, 11:29 PM CDT (04:29 UTC)
Expired
Sep 12, 2023, 1:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 683

Counties Concho County, TX, Crockett County, TX, Gillespie County, TX, Glasscock County, TX, Irion County, TX, Kerr County, TX, Kimble County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Menard County, TX, Mills County, TX, Pecos County, TX, Reagan County, TX, San Saba County, TX, Schleicher County, TX, Sterling County, TX, Sutton County, TX, Tom Green County, TX, Upton County, TX

The radar

The San Angelo radar (KSJT), 29 km from the middle of the area, began a volume at 04:29 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

Midland Regional, TX (KMAF), launched 00:00Z, 4.5 hours before the alert went out and 195 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, Midland Regional, TX at 00:00Z on 2023-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 749 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, Midland Regional, TX at 00:00Z on 2023-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 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
749 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
2662 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.5

Open this sounding in Storm Lab

The text

As transmitted.

803 
ACUS11 KWNS 120429
SWOMCD
SPC MCD 120429 
TXZ000-120630-

Mesoscale Discussion 2139
NWS Storm Prediction Center Norman OK
1129 PM CDT Mon Sep 11 2023

Areas affected...southwest into central Texas

Concerning...Severe Thunderstorm Watch 683...

Valid 120429Z - 120630Z

The severe weather threat for Severe Thunderstorm Watch 683
continues.

SUMMARY...Strong to severe wind gusts remain possible with outflow
moving out of the Permian Basin toward parts of central Texas.

DISCUSSION...Multiple severe wind gusts have been measured over the
past two hours as storms developed southeastward out of NM. The
primary outflow surge remains intact and has moved through the MAF
area, and currently extends southwestward toward FST. A separate,
southward-moving outflow regime exists ahead of the western surge,
with robust storms from SJT eastward toward BWD. In between the two
outflows, around 1000 J/kg MLCAPE exists per objective analysis,
with minimal CIN. Given the strong lift with the surging and
possibly intersecting outflow later tonight, much of the area within
WW 683 will experience wind gusts over 40 kt, with a few severe
gusts expected.

..Jewell.. 09/12/2023

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FWD...EWX...SJT...MAF...

LAT...LON   30570326 31050239 31610189 32050146 32160111 31810067
            31649984 31659906 31729871 31409844 30979843 30649855
            30129871 29879910 30250116 30570326

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 11, 7:36 PM CDTMesoscale DiscussionSPCAndrews, Borden, Brown, Callahan, Coke, Coleman and 25 more114 min
Sep 11, 8:58 PM CDTSevere Thunderstorm WatchSPCAndrews, Brown, Callahan, Coke, Coleman, Concho and 29 more6 hr

Nearby

Mesoscale Discussions in Texas, 2023Every mesoscale discussion in 2023

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.