Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 1794
The Storm Prediction Center issued this mesoscale discussion at Sep 30, 2021, 6:08 PM CDT for 5 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 30, 2021, 6:08 PM CDT (23:08 UTC)
- Expired
- Sep 30, 2021, 8:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 511
Counties Crockett County, TX, Irion County, TX, Reagan County, TX, Terrell County, TX, Tom Green County, TX
The radar
The Midland/Odessa radar (KMAF), 179 km from the middle of the area, began a volume at 23:08 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
Del Rio, TX (KDRT), launched 12:00Z, 11.1 hours before the alert went out and 155 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.
- Mixed-layer CAPE
- 2299 J/kg
- Mixed-layer CIN
- -31 J/kg
- Mixed-layer LCL
- 571 m above ground
- 0-6 km bulk shear
- 34 kt
- 0-1 km storm-relative helicity
- 51 m²/s²
- 0-3 km storm-relative helicity
- 6 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 2.6
The text
As transmitted.
548
ACUS11 KWNS 302308
SWOMCD
SPC MCD 302308
TXZ000-010115-
Mesoscale Discussion 1794
NWS Storm Prediction Center Norman OK
0608 PM CDT Thu Sep 30 2021
Areas affected...Portions of southwestern Texas
Concerning...Severe Thunderstorm Watch 511...
Valid 302308Z - 010115Z
The severe weather threat for Severe Thunderstorm Watch 511
continues.
SUMMARY...At least an isolated threat of large hail and damaging
winds gusts will remain possible across portions of Severe
Thunderstorm Watch 511 for the next few hours. Severe Thunderstorm
Watch 511 might need to be canceled prior to the 0200Z expiration if
overall weakening trends continue.
DISCUSSION...Latest surface observations from 23Z show a cold front
moving southward through the Transpecos region of southwest Texas,
with widely scattered thunderstorms near/along the front. Radar
imagery over the past hour or so suggests storm intensities have
likely already peaked -- due in part to the best upper-level support
beginning to move away from the area and diminishing instability
with messy storm coverage. Nevertheless, RAP mesoanaylysis suggests
pockets of MLCAPE exceeding 2000 J/kg amidst effective bulk shear
values of 30-40 knots, which will continue to support at least an
isolated threat for damaging wind gusts and large hail with the
strongest storms -- especially along/south of I-10. Another area of
thunderstorms has recently moved east of the Watch across portions
of North Central Texas (with a few MESH cores exceeding 1 inch).
While the environment east of the watch becomes less favorable
(weaker shear and instability) for severe thunderstorms rather
quickly, brief intensification may allow for localized large
hail/damaging wind gusts.
High-resolution guidance suggests thunderstorm intensities should
continue to wane over the next few hours as instability weakens
further and upper-level support continues to pull away from the
area. While Severe Thunderstorm Watch #511 currently expires at
0200Z, it may need to be canceled earlier if storm intensity trends
continue to decrease.
..Elliott.. 09/30/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...EWX...SJT...MAF...
LAT...LON 29110297 29450319 30680277 31590159 31650046 31420022
29750175 29110297SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 30, 10:38 AM CDT | Mesoscale Discussion | SPC | Brewster, Coke, Crane, Culberson, Ector, Fisher and 18 more | 3 hr |
| Sep 30, 12:44 PM CDT | Severe Thunderstorm Watch | SPC | Borden, Brewster, Coke, Crane, Crockett, Fisher and 16 more | 8 hr |
| Sep 30, 3:01 PM CDT | Mesoscale Discussion | SPC | Brewster, Coke, Crockett, Culberson, Glasscock, Irion and 11 more | 119 min |
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.