ACUS01 KWNS 251946
SWODY1
SPC AC 251945
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0245 PM CDT Sat Oct 25 2025
Valid 252000Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTH-CENTRAL TEXAS INTO SOUTHERN LOUISIANA...
...SUMMARY...
Scattered severe thunderstorms are possible today into tonight from
parts of south-central Texas into the lower Mississippi Valley.
...20z Update...
The previous forecast largely remains on track with only a slight
northward adjustment of the 5% hail/wind probabilities across
portions of central/eastern TX ahead of developing convection.
Immediately downstream of these storms, temperatures have been slow
to warm, resulting in a regional minimum of buoyancy. It remains
unclear how intense convection will be along the I-20 corridor due
to the modest buoyancy, but strong deep-layer wind shear and some
degree of air mass recovery may be sufficient for an isolated
hail/wind threat. Additional thunderstorm development to the
south/southwest along the I-35 corridor remains likely by late afternoon/evening as ascent ahead of the upper trough increases.
Temperatures across the Austin/San Antonio region (and
southeastwards along the TX coast) have increased to the mid 70s to
low 80s, which is eroding lingering inhibition and supporting MLCAPE
values upwards of 1500 J/kg. As such, the current Slight risk area
continues to highlight the best convective environment with the
expectation for increasing thunderstorm coverage heading into the
evening hours. Additional forecast details outlined in the previous
discussion below remain on track.
..Moore.. 10/25/2025
.PREV DISCUSSION... /ISSUED 1128 AM CDT Sat Oct 25 2025/
...South-Central/Coastal Texas into Louisiana...
Extensive convective overturning occurred overnight/early this
morning across central/east TX into LA with an MCS that has decayed
across coastal LA as of late this morning. Recent radar and visible
satellite imagery show a band of outflow arcing from south-central
LA across the northwest Gulf and into south-central TX. The degree
of destabilization that can occur today from central/east TX into LA
in the wake of this outflow remains uncertain. Cool mid-level
temperatures will persist through the period across the southern
Plains as a closed mid/upper-level low moves slowly eastward from
the TX Panhandle across OK. The best potential for weak to locally
moderate instability to develop this afternoon may exist over
portions of central into southeast TX, where some cloud breaks are
noted and generally mid 60s surface dewpoints are still in place.
Current expectations are for scattered thunderstorms to redevelop
this afternoon along a secondary outflow boundary extending across
central into east/coastal TX, as ascent associated with a 40-50+ kt
mid-level jet rounding the base of the upper trough/low overspreads
this area. Deep-layer shear will be strong enough to support
supercells with this initial activity. Large hail may occur with any
sustained supercell. With time this evening, outflow interactions
should encourage another MCS to develop across southeast TX and
vicinity. Scattered damaging winds should become a greater concern
as this MCS develops eastward across parts of LA overnight into
early Sunday morning. Although low-level flow is not forecast to be
overly strong, a few tornadoes still appear possible both with the
initial supercells and embedded circulations within the MCS. Given observational trends and recent model guidance suggesting robust destabilization will struggle with northward extent, severe
probabilities have been confined/adjusted southward across
central/east TX into LA with this update.
...Pacific Northwest...
A mid-level trough and associated strong jet will move eastward
across parts of the Pacific Northwest through the period. Pronounced large-scale ascent will prove favorable for thunderstorm development
along coastal WA/OR. A brief waterspout/tornado could develop/move
ashore near the immediate coast, and marginally severe wind gusts
will be possible as low-topped cells move inland. Separately, parts
of southeast WA into northeast OR and ID may see isolated to
scattered thunderstorm development late this afternoon, with
occasional severe gusts possible with the more robust convection.
Weak instability forecast across both areas should keep the overall
severe threat rather isolated/marginal.
$$
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