560
ACUS01 KWNS 011948
SWODY1
SPC AC 011946

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 PM CDT Sat Nov 01 2025

Valid 012000Z - 021200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL/SOUTH TEXAS...

...SUMMARY...
Isolated to scattered severe thunderstorms capable of producing
large hail and locally damaging winds will be possible late this
afternoon and evening across portions of south Texas.

...20z Update...
A westward expansion was given to the Marginal Risk across portions
of the Texas Hill Country to account for ongoing trends. Convection
has begun with increasing ascent near the surface low/cold front
across portions of south-central/central Texas. This is further west
than originally anticipated, with recent HRRR trends indicating that
supercells may form further inland. Confidence remains low, with
MLCIN remaining to the coast in RAP analysis and as observed in
recent soundings from 18z at CRP. Nonetheless, with a few more hours
of heating remaining it remains possible that a cell or two may form
further west warranting the small nudge westward of low
probabilities.

..Thornton.. 11/01/2025

.PREV DISCUSSION... /ISSUED 1118 AM CDT Sat Nov 01 2025/

...South Texas...
Recent visible satellite imagery, surface observations, and the VWPs
from CRP/BRO indicate low-level moisture continues to stream
northward across parts of the middle TX Coast and deep south TX
ahead of a surface cold front. Within broader large-scale upper
troughing encompassing much of the central/eastern CONUS, a
mid-level shortwave trough over the southern High Plains late this
morning will dig quickly southeastward across TX by this evening.
Ascent preceding this shortwave trough will likely encourage
scattered convective development by 22-00Z across portions of
coastal TX and perhaps farther inland near the southeastward-moving
cold front. Even though the low-level moisture return is not
expected to be overly deep/rich, the presence of modestly steepened
mid-level lapse rates amid strong diurnal heating will likely
support the development of at least weak instability by late this
afternoon.

Modest east-southeasterly low-level winds will veer to
west-northwesterly and strengthen through mid/upper levels,
fostering strong (40-50+ kt) deep-layer shear. Resultant
elongated/nearly straight hodographs aloft will easily support
organized updrafts, including the potential for multiple supercells
capable of producing mainly large hail. There is still some
uncertainty with how many robust thunderstorms can develop over
land, and how quickly they strengthen before moving offshore into
the western Gulf. Still, a more favorable corridor for large hail
should exist late this afternoon and evening from the vicinity of
Corpus Christi northward towards/near Victoria, where a Slight Risk
has been added with this update.

$$