ACUS03 KWNS 111857
SWODY3
SPC AC 111856
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 PM CST Tue Nov 11 2025
Valid 131200Z - 141200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears to remain negligible across much
of the U.S. Thursday through Thursday night.
...Discussion...
Models indicate that there will likely be little change to the
large-scale pattern across eastern North America into the Atlantic
through this period, with a blocking mid-level high forecast to be
maintained near/offshore of the southern Greenland Atlantic coast.
Upstream, it appears that flow will remain more progressive across
the mid-latitude Pacific into western North America.
The northern portion of a splitting mid/upper trough across the
eastern Pacific may be reinforced by a digging short wave
perturbation, while progressing inland across British Columbia and
the Pacific Northwest. It appears that this will provide support
for notable surface cyclogenesis to the lee of the Canadian/northern
U.S. Rockies. While initial surface troughing southward through the
remainder of the high plains into the Texas Big Bend vicinity may be maintained, the development of a deep southerly moist return flow
off the western Gulf Basin still appears unlikely through 12Z Friday
and beyond.
Spread concerning the subsequent evolution of the mid-level low
within the southern portion of the splitting eastern Pacific trough
remains more substantive. However, the initially deep associated
surface cyclone is generally forecast to rapidly weaken offshore of
the southern Oregon/northern California coast, while the mid-level
cold core (initially including 500 mb temperatures of -24 to -28 C)
continues to dig well offshore of the central/southern California
coast.
...California...
With the mid-level cold core forecast to dig offshore, the
development of thermodynamic profiles potentially conducive to an
appreciable risk for convection capable of producing lightning
(i.e., 10 percent or greater probabilities) remains unclear.
However, high resolution, convection allowing ensemble output and
related guidance suggest at least minimal, though diminishing,
probabilities for a pre-frontal thunderstorm or two may be
maintained across and inland of the northern California coast
Thursday morning.
As a southerly low-level jet (still on the order of 50-70 kt around
850 mb) impinges on the Siskiyous/Mount Shasta into northern Sierra
Nevada vicinity, it also might not be out of the question that
strong orographic forcing for ascent contributes to sufficient
destabilization for convection briefly becoming capable of producing
a lightning strike or two into at least midday Thursday.
..Kerr.. 11/11/2025
$$
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