627
ACUS03 KWNS 311932
SWODY3
SPC AC 311930

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0130 PM CST Wed Dec 31 2025

Valid 021200Z - 031200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
General thunderstorms are forecast, mainly Friday night into early
morning Saturday, across the central Gulf Coast and Deep South, as
well as along coastal areas of central and northern California and
southwest Orgeon.

...LA/MS/AL vicinity...
A low-amplitude midlevel shortwave trough is forecast to move from
the south-central Plains towards the TN Valley on Friday. A somewhat
stronger upstream shortwave trough will move quickly
east-southeastward from the Great Basin toward parts of north/east
TX. A surface low initially over north TX is expected to move
eastward toward northern MS/AL by Friday night. Increasing low-level
moisture within the warm sector of this low will allow for modest
diurnal destabilization, with MLCAPE potentially increasing to
near/above 500 J/kg across parts of LA/MS, in advance of a trailing
cold front.

Strengthening deep-layer shear will become conditionally favorable
for organized convection, but potential for robust surface-based
development may be limited by poor midlevel lapse rates and
relatively modest large-scale ascent within the warm sector. It
still appears that the bulk of any thunderstorm development will be
somewhat elevated and occur near and north of the surface warm front
across northern MS/AL/GA and southern TN, primarily during the
evening and overnight. At this time, elevated buoyancy appears
insufficient to support an organized severe threat with this
activity. However, if confidence increases regarding development of
near-surface-based storms within the warm sector of the
eastward-moving low, then severe probabilities may eventually be
needed.

...Coastal northern CA/southwest OR...
A deep mid/upper-level trough will gradually move eastward and
approach the Pacific Coast by Friday night, as a strong jet begins
to impinge upon areas of central/northern CA and the Pacific
Northwest. A deepening surface low associated with this trough is
expected to remain offshore through Saturday morning. The strongest
low-level flow (50+ kt at 850 mb) will occur within the warm
conveyor of this cyclone, where instability is expected to remain
negligible.

Late in the period, some cooling aloft and steepening lapse rates
may approach coastal areas of central/northern CA and southwest OR.
This may allow for development of generally weak convection with
sproadic lightning flashes. Low-level flow is forecast to remain
rather strong (35-45 kt at 850 mb) as midlevel lapse rates begin to
steepen, and any lightning-producing convection could be coincident
with gusty winds. However, any convective contribution to
damaging-wind potential may be limited by very meager surface-based
buoyancy through the end of the period.

..Dean.. 12/31/2025

$$