Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 1793

September 30, 202117 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Sep 30, 2021, 3:01 PM CDT for 17 counties in Texas. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued
Sep 30, 2021, 3:01 PM CDT (20:01 UTC)
Expired
Sep 30, 2021, 5:00 PM CDT
In force
119 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 511

Counties Brewster County, TX, Coke County, TX, Crockett County, TX, Culberson County, TX, Glasscock County, TX, Irion County, TX, Jeff Davis County, TX, Nolan County, TX, Pecos County, TX, Presidio County, TX, Reagan County, TX, Runnels County, TX, Sterling County, TX, Taylor County, TX, Terrell County, TX, Tom Green County, TX, Upton County, TX

The radar

The Midland/Odessa radar (KMAF), 118 km from the middle of the area, began a volume at 20:04 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 12:00Z, 8.0 hours before the alert went out and 118 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 12:00Z on 2021-09-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1726 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 12:00Z on 2021-09-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 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
1726 J/kg
Mixed-layer CIN
-108 J/kg
Mixed-layer LCL
1297 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
8 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

882 
ACUS11 KWNS 302002
SWOMCD
SPC MCD 302001 
TXZ000-302200-

Mesoscale Discussion 1793
NWS Storm Prediction Center Norman OK
0301 PM CDT Thu Sep 30 2021

Areas affected...Parts of southwestern Texas into parts of the Texas
South Plains

Concerning...Severe Thunderstorm Watch 511...

Valid 302001Z - 302200Z

The severe weather threat for Severe Thunderstorm Watch 511
continues.

SUMMARY...Scattered strong to severe storms will continue to develop
through 4-6 PM CDT, posing a risk for large hail, particularly
across areas south through east of Fort Stockton.

DISCUSSION...The surface cold front has advanced southward into the
the Pecos Valley and through much of the Texas South Plains, with
widely scattered strong thunderstorm development ongoing along it
and across the higher terrain of southwestern Texas.  A further
increase in coverage of storms appears probable through 21-23Z,
supported by peak late afternoon boundary-layer instability.

Latest Rapid Refresh output suggests that there has been sufficient
strengthening of southwesterly mid/upper flow across the northern
Mexican Plateau into southwest Texas to contribute to moderate to
strong deep-layer shear across and southeast through east of the
Davis Mountains vicinity.  One or two sustained supercells may
develop across this region, posing the most prominent risk for large
hail.

..Kerr.. 09/30/2021

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

ATTN...WFO...EWX...SJT...MAF...EPZ...

LAT...LON   30700289 31260238 31660193 32050137 32470036 32089924
            30330157 29640298 29430394 30370463 30900528 31610512
            31660424 30730378 30700289

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 30, 10:38 AM CDTMesoscale DiscussionSPCBrewster, Coke, Crane, Culberson, Ector, Fisher and 18 more3 hr
Sep 30, 12:44 PM CDTSevere Thunderstorm WatchSPCBorden, Brewster, Coke, Crane, Crockett, Fisher and 16 more8 hr
Sep 30, 6:08 PM CDTMesoscale DiscussionSPCCrockett, Irion, Reagan, Terrell, Tom Green2 hr

Nearby

Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021

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.