Alert archive / Texas / Mesoscale Discussions in 2021

Mesoscale Discussion 1880

October 21, 2021Brewster County, Jeff Davis County, Presidio County, Texas

The Storm Prediction Center issued this mesoscale discussion at Oct 21, 2021, 3:24 PM CDT for Brewster County, Jeff Davis County, Presidio County, Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Oct 21, 2021, 3:24 PM CDT (20:24 UTC)
Expired: Oct 21, 2021, 6:00 PM CDT
In force: 3 hr
Issued by: the Storm Prediction Center
Concerning: Severe potential...watch unlikely
Chance of a watch: 5%

Counties Brewster County, TX, Jeff Davis County, TX, Presidio County, TX

The radar

The Midland/Odessa radar (KMAF), 244 km from the middle of the area, began a volume at 20:25 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, 8.4 hours before the alert went out and 244 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: 1076 J/kg
Mixed-layer CIN: -203 J/kg
Mixed-layer LCL: 820 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 117 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

761 
ACUS11 KWNS 212025
SWOMCD
SPC MCD 212024 
TXZ000-212300-

Mesoscale Discussion 1880
NWS Storm Prediction Center Norman OK
0324 PM CDT Thu Oct 21 2021

Areas affected...Portions of far west TX

Concerning...Severe potential...Watch unlikely 

Valid 212024Z - 212300Z

Probability of Watch Issuance...5 percent

SUMMARY...Isolated storms capable of producing occasional gusty
winds and hail should continue through the rest of the afternoon.
Watch issuance is not expected.

DISCUSSION...A few storms have developed this afternoon over the
Davis Mountains and vicinity in far west TX. This region remains
displaced to the south of stronger mid-level flow across the
northern/central CONUS. Still, there is modest veering/strengthening
of the wind field with height through mid levels per recent VWPs
from KMAF. Around 20-25 kt of deep-layer shear should help foster
occasional storm organization. The presence of steep mid-level lapse
rates observed on the 12Z MAF sounding suggests some threat for
isolated marginally severe hail with the strongest storms. Diurnal
heating of the boundary layer has also steepened low-level lapse
rates, and occasional strong to severe downdraft winds may also
occur as the cores collapse. With a lack of stronger flow aloft,
storm motions should remain rather slow, with the overall severe
threat likely remaining quite isolated this afternoon. Therefore,
watch issuance is not expected.

..Gleason/Bunting.. 10/21/2021

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

ATTN...WFO...MAF...

LAT...LON   30520459 30910411 31050357 30590277 30060280 29600321
            29640398 29870444 30150464 30520459

Nearby

Mesoscale Discussions in Texas, 2021 Every 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.