Mesoscale Discussion 1055

Issued

Jun 21, 2021, 5:29 PM CDT (22:29 UTC)

Expired

Jun 21, 2021, 7:30 PM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch unlikely

Chance of a watch

20%

The San Angelo radar (KSJT), 38 km from the middle of the area, began a volume at 22:29 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.

906 
ACUS11 KWNS 212230
SWOMCD
SPC MCD 212229 
TXZ000-220030-

Mesoscale Discussion 1055
NWS Storm Prediction Center Norman OK
0529 PM CDT Mon Jun 21 2021

Areas affected...Southwest to central Texas

Concerning...Severe potential...Watch unlikely 

Valid 212229Z - 220030Z

Probability of Watch Issuance...20 percent

SUMMARY...Isolated to scattered thunderstorms will continue to
develop along a surface cold front this evening. Storms may
intensify enough to pose a hail/wind threat, but the risk should be
limited enough to preclude a watch.

DISCUSSION...Recent GOES imagery and GLM data show agitated cumulus
and one or two convective towers with a few lightning strikes along
the surface cold front that is zonally draped across TX. Ahead of
this front, temperatures have warmed into the 90s with dewpoints in
the upper 60s and low 70s. This boundary-layer warming has helped
erode mixed-layer inhibition, and combined with steep lapse rates
aloft is supporting 2000-3000 J/kg MLCAPE. Although some lingering
inhibition remains, lift along the cold front should be sufficient
for at least isolated to scattered thunderstorms over the next 1-2
hours from central to southwest TX. Despite somewhat weak wind shear
(20-30 knots of effective bulk shear noted in recent analyses), this
thermodynamic environment is supportive of at least a brief hail
threat with strong updraft pulses, and 8-9 C/km low-level lapse
rates may allow for a few damaging wind gusts. Although one or two
organized cells are possible, the coverage of the severe threat is
generally expected to be dispersed given the residual capping and
somewhat weak deep-layer shear. Consequently, a watch is not
expected.

..Moore/Grams.. 06/21/2021

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

ATTN...WFO...FWD...EWX...SJT...MAF...

LAT...LON   31610233 31940051 32379897 32639729 32459678 32099657
            31619653 31089683 30749783 30409870 30200034 30050110
            29900151 29980226 29770302 30150315 30460348 31210310
            31530287 31610233

Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021

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.