Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0743 PM CDT Wed May 20 2026

Valid 210100Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
WEST AND SOUTHWEST TEXAS INTO SOUTH-CENTRAL TEXAS...

...SUMMARY...
Isolated severe storms with hail and strong wind gusts will be
possible across parts of west and southwest Texas this evening.
Isolated severe gusts may also occur in south-central Texas in the
late evening and early overnight period.

...West, Southwest and South-central Texas...
A mid-level shortwave trough is evident over far west Texas.
Large-scale ascent associated with the trough is providing support
for scattered thunderstorm development early this evening. The
storms are located near a quasi-stationary front extending eastward
from near Fort Stockton into the Texas Hill Country. To the south of
the front, surface dewpoints are mostly in the mid to upper 60s F.
The RAP suggests that MLCAPE ranges from around 1000 J/kg near the
front to about 2500 J/kg in the lower Rio Grande Valley southeast of
Del Rio. As the shortwave trough moves into west-central Texas over
the next few hours, new convection is expected to initiate from the
far western Texas Hill Country into southwest Texas. In addition to
moderate instability, the Del Rio 00Z sounding has 0-6 km shear
around 30 knots with 700-500 mb lapse rates approaching 7.5 C/km.
This environment will support isolated severe storm development.
Rotating cells should be capable of isolated large hail. A few
severe wind gusts could also occur. The potential for isolated
severe gusts may continue after midnight across parts of
south-central Texas, as a convective cluster crosses the Rio Grande
River.

..Broyles.. 05/21/2026