ACUS02 KWNS 241727
SWODY2
SPC AC 241725
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1225 PM CDT Fri Oct 24 2025
Valid 251200Z - 261200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
CENTRAL TEXAS INTO THE SABINE RIVER VALLEY...
...SUMMARY...
Scattered severe thunderstorms are possible tomorrow (Saturday),
across Texas into the Sabine River Valley. All severe hazards are
possible. A couple of severe gusts or a brief tornado are also
possible over parts of the Pacific Northwest.
...Synopsis...
A mid-level trough will traverse the southern U.S., while an upper
troughs ejects into the Atlantic and a more pronounced, larger scale
upper trough impinges on the Interior West tomorrow (Saturday).
Ahead of the southern U.S. upper trough, low-level troughing will
encourage southerly return flow from the Gulf, resulting in airmass modification amid a warm-air/moisture advection regime. As upper
support from the aforementioned trough encourages deep-layer ascent
amid this moist airmass, thunderstorms will continue to develop
and/or persist across Texas into the Sabine River Valley. Given
adequate vertical wind shear accompanying this moist low-level
airmass, multiple rounds of strong to potentially severe storms are
likely. Strong flow aloft and associated vertical wind shear will
overspread the Pacific Northwest, amid scant buoyancy, to support
low-topped but potentially strong storms.
...Portions of Texas into the Sabine River Valley...
Thunderstorms (perhaps in the form of an MCS), should be ongoing at
the start of the period across TX, remnant from the Day 1 period.
These storms will be preceded by a moist low-level airmass (i.e. at
least mid to upper 60s F dewpoints), yielding 1000-2000 J/kg MLCAPE
given modest mid-level lapse rates. A 35-45 kt southerly low-level
jet will already be in place over eastern TX toward the Sabine River
Valley, which will promote sizeable, curved low-level hodographs. As
such, multicells and/or supercells embedded within this MCS will
support all hazards during the morning hours, with the best chance
for isolated tornadoes being with supercells that can remain
discrete. These storms will approach the Gulf shoreline by around
Noon, and are poised to weaken in the process.
The progression of the earlier storms complicates severe potential
for the central TX into the Sabine River Valley later Saturday into
Saturday night. This is when the primary wave will overspread the
region, coincident with strengthening and some eastward shift of the
low-level jet. At least one additional, pronounced round of
thunderstorms is expected to develop across central TX during the
afternoon, and progress across LA during the evening/overnight
hours. Should adequate airmass destabilization occur behind the
preceding round of storms, deep-layer and low-level shear will be
adequate to support supercell structures and subsequent upscale
growth into a QLCS. In addition to large hail (especially over
central TX), sizeable and curved low-level hodographs will support
tornado potential. The best chance for tornadoes with the second
round of storms will be over LA late Saturday, when the storms
traverse the low-level jet axis.
...Portions of the Pacific Northwest...
As broad and pronounced mid-level trough overspreads the Pacific
Northwest through the morning to late afternoon hours tomorrow
(Saturday), 80-100 kts of westerly mid-level flow will overspread
the region. Some forecast soundings indicate 50 kt westerly flow
extending as low as 700 mb in altitude, suggesting that little
mechanical downward momentum transport is needed to support strong
to potentially severe wind gusts. Strong deep-layer ascent, amid
scant but possibly adequate buoyancy, will encourage the development
of at least one (possibly multiple) low-topped convective bands.
These bands (regardless of lightning potential) may produce a couple
of severe gusts, especially over higher terrain, warranting the
introduction of Category 1/Marginal risk probabilities. Low-end
tornado probabilities have also been added to the OR coastline,
where a few low-topped supercells may promote a landfalling brief
tornado.
..Squitieri.. 10/24/2025
$$
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