ZCZC SPCSWOMCD ALL
ACUS11 KWNS 182052 
SPC MCD 182052 
TXZ000-182215-

Mesoscale Discussion 0674
NWS Storm Prediction Center Norman OK
0352 PM CDT Tue May 18 2021

Areas affected...Portions of south-central TX

Concerning...Tornado Watch 188...

Valid 182052Z - 182215Z

The severe weather threat for Tornado Watch 188 continues.

SUMMARY...The greatest near-term severe threat across Tornado Watch
188 should focus east of San Antonio and south of Austin.

DISCUSSION...A supercell anchored along a surface boundary and
embedded within a small cluster has recently produced 1.25 inch hail
to the northeast of San Antonio and a 67 mph wind gust at the New
Braunfels airport (KBAZ). Strong low-level velocities have also been
noted from the KEWX radar with this storm. The environment
downstream of this activity should remain favorable for severe
storms, with MLCAPE generally ranging from 1500-2000 J/kg and 35-40
kt of effective bulk shear present across south-central TX. Both
large hail and damaging wind gusts should remain the primary severe
threat for the next hour or two. Other convection is attempting to
strengthen to the south of the ongoing cluster in a modest low-level
warm advection regime. These storms may also become severe if they
strengthen further. Although the east-southeasterly low-level flow
to the south of the boundary is not overly strong per recent
mesoanalysis estimates, it may be strong enough to support an
isolated tornado, especially with any storm that can remain anchored
to the remnant outflow boundary.

..Gleason.. 05/18/2021

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

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

LAT...LON   29709807 30089808 30169761 30139670 29749644 29319652
            29149674 29229788 29709807 

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