Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 1790
The Storm Prediction Center issued this mesoscale discussion at Sep 29, 2021, 2:06 AM CDT for Calhoun County, Victoria County, Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 29, 2021, 2:06 AM CDT (07:06 UTC)
- Expired
- Sep 29, 2021, 4:30 AM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 5%
Counties Calhoun County, TX, Victoria County, TX
The radar
The Corpus Christi radar (KCRP), 107 km from the middle of the area, began a volume at 07:08 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
Brownsville Intl, TX (KBRO), launched 00:00Z, 7.1 hours before the alert went out and 304 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
- 2875 J/kg
- Mixed-layer CIN
- -44 J/kg
- Mixed-layer LCL
- 918 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 10 m²/s²
- 0-3 km storm-relative helicity
- 38 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
810
ACUS11 KWNS 290707
SWOMCD
SPC MCD 290706
TXZ000-290930-
Mesoscale Discussion 1790
NWS Storm Prediction Center Norman OK
0206 AM CDT Wed Sep 29 2021
Areas affected...a small of part of the middle Texas Coast
Concerning...Severe potential...Watch unlikely
Valid 290706Z - 290930Z
Probability of Watch Issuance...5 percent
SUMMARY...A small window exists for a weak supercell or two along a
boundary extending southeast from an MCS to the middle Texas Coast.
DISCUSSION...A quasi-stationary front currently stretches from the
Gulf of Mexico across Aransas, Calhoun, Refugio, and Goliad
counties. A slow-moving supercell has persisted for quite some time
just offshore, with weak to sometimes moderate rotation.
Quickly approaching the region is an MCS with outflow, now
approaching northern Goliad and Victoria counties. However, small
cells along the stationary front preceding the MCS have recently
shown rotation as well.
If convective trends continue to increase in this small area, a
brief/weak tornado could not be ruled out. Any threat would be tied
to the stationary boundary, with threat ending once outflow
undercuts from the northwest. Effective SRH values of only 100-150
and weak winds aloft suggest minimal overall severe risk.
..Jewell/Edwards.. 09/29/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 28469730 28649733 28929740 28949723 29059689 28829667
28519640 28349631 28189659 28289690 28469730SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 28, 7:01 PM CDT | Mesoscale Discussion | SPC | Atascosa, Bandera, Bee, Bexar, DeWitt, Dimmit and 14 more | 89 min |
| Sep 29, 3:13 PM CDT | Mesoscale Discussion | SPC | Archer, Brown, Callahan, Clay, Coleman, Eastland and 5 more | 2 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.