Accompanying MCD discussion.
Mesoscale Discussion 0382 NWS Storm Prediction Center Norman OK 1243 PM CDT Wed Apr 14 2021
Areas affected...portions of the Texas Coastal Plain
Concerning...Severe potential...Watch possible
Valid 141743Z - 141945Z
Probability of Watch Issuance...40 percent
SUMMARY...Storm development over the next couple of hours will be accompanied by some increase in risk for large hail and locally strong/damaging wind gusts through this afternoon. A WW may be required.
DISCUSSION...Latest surface analysis shows a cold front across western portions of the Texas Coastal Plain/eastern fringes of the Hill Country, and then westward into the Edwards Plateau. Meanwhile, a sea-breeze boundary has pushed into coastal counties, with high theta-e marine air along and east of this boundary.
Though capping (near 700 mb) remains established across the area, continued heating/mixing of the boundary layer will weaken the cap locally -- particularly near the aforementioned surface boundaries where ascent is locally maximized. With steep lapse rates overlying this region above the capping layer, the destabilizing environment -- represented by mixed-layer CAPE values now in excess of 2500 J/kg across the region per RUC-based objective analyses -- combined with the weakening cap will support local/robust updraft development.
While deep-layer shear is not excessive, partially owing to modest low-level flow, ample (around 30 kt) mid-level west-southwesterlies are contributing to shear sufficient for multicell organization, and even some mid-level updraft rotation. As such, potential for hail and/or locally strong outflow winds will be possible with a few of the strongest storms. We will continue to monitor development, for signs that convective development/coverage may warrant WW issuance.
...Please see www.spc.noaa.gov
for graphic product...
LAT...LON 29279811 29559761 29829683 29909598 30189492 29659475 28749616 28169709 28299783 28449828 28839839 29279811