Alert archive / Texas / Mesoscale Discussions in 2022

Mesoscale Discussion 1921

November 4, 202211 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 4, 2022, 6:26 PM CDT for 11 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Nov 4, 2022, 6:26 PM CDT (23:26 UTC)
Expired: Nov 4, 2022, 8:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch possible
Chance of a watch: 40%

Counties Bastrop County, TX, Caldwell County, TX, DeWitt County, TX, Goliad County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Karnes County, TX, Lavaca County, TX, Travis County, TX, Wilson County, TX

The radar

The Austin/San Antonio radar (KEWX), 43 km from the middle of the area, began a volume at 23:27 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

Corpus Christi, TX (KCRP), launched 12:00Z, 11.4 hours before the alert went out and 190 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1579 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 579 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 187 m²/s²
0-3 km storm-relative helicity: 316 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 9.4

Open this sounding in Storm Lab

The text

As transmitted.

785 
ACUS11 KWNS 042327
SWOMCD
SPC MCD 042326 
TXZ000-050130-

Mesoscale Discussion 1921
NWS Storm Prediction Center Norman OK
0626 PM CDT Fri Nov 04 2022

Areas affected...south central/southern Texas

Concerning...Severe potential...Watch possible 

Valid 042326Z - 050130Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms may gradually develop across the region
through 8-9 PM CDT.  The evolution of isolated supercell structures
posing a risk for severe hail and locally strong gusts appears
briefly possible, before a cold frontal passage weakens storms later
this evening.  It is not clear a severe weather watch will be
needed, but trends are being monitored.

DISCUSSION...Mixed-layer CAPE on the order of 2000-3000 J/kg appears
to have developed in a narrow corridor along a slow moving dryline
across south central Texas, with deepening convective development
evident near/north of San Antonio into the Austin vicinity. 
Although stronger mid/upper forcing for ascent downstream of the
vigorous  short wave trough, now beginning to pivot northeast of the
Texas South Plain, will generally continue to pass to the northeast
of the region, associated mid-level cooling is weakening mid-level
inhibition east of the Hill Country.  

Based on current trends and model output, at least isolated vigorous
thunderstorm development appears possible within the next hour or
two.  Although low-level wind fields are tending to veer and weaken,
deep-layer shear beneath 50+ kt southwesterly mid-level flow is
strong and supportive of supercells which could pose a risk for
severe hail and wind.  However, this risk may remain relatively
isolated and short-lived, as a pair of cold fronts quickly advance
southeastward toward the Texas coastal plain through 03-04Z, and
tend to undercut the convective development.

..Kerr/Guyer.. 11/04/2022

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

ATTN...WFO...HGX...CRP...EWX...

LAT...LON   29399842 30109804 30399761 29739685 29089696 28539750
            28569827 29399842

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 3, 10:27 PM CDT	Mesoscale Discussion	SPC	Hemphill, Lipscomb, Ochiltree, Roberts	3 hr
Nov 4, 2:53 AM CDT	Mesoscale Discussion	SPC	Collingsworth, Gray, Hemphill, Lipscomb, Roberts, Wheeler	3 hr
Nov 4, 11:28 AM CDT	Mesoscale Discussion	SPC	Anderson, Bell, Bosque, Bowie, Camp, Cherokee and 45 more	62 min
Nov 4, 1:02 PM CDT	Tornado Watch	SPC	Anderson, Bell, Bosque, Camp, Cherokee, Collin and 40 more	7 hr
Nov 4, 2:47 PM CDT	Mesoscale Discussion	SPC	Bosque, Collin, Cooke, Dallas, Delta, Denton and 17 more	118 min
Nov 4, 5:13 PM CDT	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Delta, Franklin, Gregg and 17 more	92 min
Nov 4, 5:36 PM CDT	Tornado Watch	SPC	Angelina, Bowie, Brazos, Burleson, Camp, Cass and 26 more	6 hr

Nearby

Mesoscale Discussions in Texas, 2022 Every mesoscale discussion in 2022

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.