Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0644 AM CST Thu Dec 25 2025

Valid 251300Z - 261200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE
CALIFORNIA COAST AND PORTIONS OF THE CENTRAL VALLEY...

...SUMMARY...
An isolated risk for severe gusts and localized wind damage, and
perhaps a brief tornado will be possible today along much of the
California Coast and portions of the Central Valley.

... California ...
Water-vapor imagery early this morning shows a mid-level low over
the eastern Pacific and a negative-tilt shortwave trough moving
northward along the northern CA and OR coast.  An upstream mid-level
speed max and associated vorticity max will move cyclonically
through the base of the eastern Pacific low/trough and approach San
Francisco Bay and northern CA this evening and subsequently move
into eastern OR by early Friday morning.  

Strong to locally severe thunderstorms mainly capable of a
severe-wind hazard will potentially continue on an isolated basis
this morning from the Central Valley/central coast and perhaps
include portions of southern CA.  The low CAPE/high shear
environment will potentially support strong/locally severe
convection contingent on sufficient updraft development.  Forecast
low-level hodographs will remain sufficiently enlarged to yield a
low risk for a brief tornado across much of the Marginal Risk (level
1 of 5) area.  By this afternoon, model guidance indicates low-level
flow will weaken before re-intensifying towards evening in
association with the arrival of the next speed max.  A mix of linear
bands and cellular convective structures may continue to pose an
intermittent risk for isolated damaging gusts and perhaps a brief
tornado into tonight.

..Smith/Weinman.. 12/25/2025