RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Thu Dec 25 07:01:01 UTC 2025.
No Mesoscale Discussions are in effect as of Thu Dec 25 07:01:01 UTC 2025.
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1137 PM CST Wed Dec 24 2025
Valid 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE
CALIFORNIA COAST AND PORTIONS OF THE CENTRAL VALLEY...
...SUMMARY...
Thunderstorms with potential to produce marginally severe wind gusts
and perhaps a brief tornado will be possible on Thursday along much
of the California Coast and portions of the Central Valley.
... Synopsis ...
A highly amplified pattern will persist across the US as a deep
trough over the eastern Pacific is maintained and a ridge builds
over the central US. A series of embedded shortwave troughs within
the eastern Pacific trough will impact the West Coast on Christmas
and Christmas night.
... California ...
The first of these shortwave troughs will be moving across the
region at the start of the forecast period, bringing with it a band
of strongly forced convection, likely located across portions of the
central coast of California into the Central Valley. As the
shortwave trough takes on an increasingly negative tilt, a 50-60
knot southerly low-level jet will be maintained allowing for
sufficient low-level theta-e advection to support a modest 100-300
J/kg of surface-based CAPE. As the convective band interacts with
this strong low-level kinematic field, gusty/damaging convective
winds may be realized at the surface, particularly with the stronger
convective elements. Forecast low-level hodographs ahead of this
convective line feature sufficient low-level curvature to support a
brief tornado should any convective element realize true
surface-based buoyancy. As the morning progresses, the
aforementioned shortwave trough will lift north then northwest
within the broader cyclonic flow across the eastern Pacific whereas
the band of convection slowly advances south and east. By midday,
the low-level wind fields should weaken sufficiently in response to
the departing shortwave trough to reduce the potential of damaging
winds/tornadoes across far southern California.
By mid-afternoon, another shortwave trough will approach the central
and northern California coast. In response, the low-level wind
fields will once again strengthen, albeit perhaps not to the extent
as with the morning wave. Another band or bands of strongly forced
convection are expected to develop across the eastern Pacific and
approach coastal areas of central California after 00Z (4 PM PT). As
was the case with the morning convection, the strongest convective
elements may be capable of mixing down the stronger winds aloft
resulting in the potential for isolated strong thunderstorm winds.
..Marsh/Squitieri.. 12/25/2025
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CST Thu Dec 25 2025
Valid 261200Z - 271200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe storms are not expected across the continental U.S. Friday or
Friday night.
...Synopsis...
A mid-level ridge will move across the central U.S. on Friday, as a
trough moves into the western states. Isolated thunderstorms will be
possible during the day from near the trough in central California
eastward into southwest Nevada. Additional thunderstorms will be
possible in the afternoon across parts of the Intermountain West as
surface temperatures warm. A third area with thunderstorm potential
will develop in parts of the central Appalachians as a shortwave
trough moves southeastward across the region. No severe threat is
expected over the continental U.S. on Friday or Friday night.
..Broyles.. 12/25/2025
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1244 AM CST Thu Dec 25 2025
Valid 251200Z - 261200Z
...Synopsis...
An upper ridge will prevail over the central CONUS as a mid-level
trough over the Interior West de-amplifies, with embedded
perturbations impinging on the Rockies today. This will support the
eastward progression of a surface low over the northern Plains,
which in turn will lead to dry downslope flow along the lee of the
Rockies. By afternoon widespread 10-15 mph sustained westerly
surface winds will generally coincide with 15-25 percent RH.
Elevated highlights are in place across portions of the Texas
Panhandle and immediate surrounding areas, where the best overlap of
15+ mph winds, 15-20 percent RH, and dry fuels should occur.
..Squitieri.. 12/25/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1250 AM CST Thu Dec 25 2025
Valid 261200Z - 271200Z
...Synopsis...
Upper ridging will gradually shunt eastward from the Plains to the
Midwest on Friday as an upper trough impinges on the Rockies. At the
surface, lee troughing will intensify over the Plains, leading to
another day of at least modestly dry downslope flow along the High
Plains. Similar to Day 1, Elevated highlights have been introduced
for the Texas Panhandle and surrounding areas. Here, 15+ mph
sustained westerly surface winds will coincide with 20 percent RH,
atop fuels that continue to cure given dry air and longer term lack
of rainfall.
..Squitieri.. 12/25/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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