SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1256 AM CST Wed Dec 24 2025
Valid 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE CENTRAL CALIFORNIA COAST...
...SUMMARY...
Thunderstorms with potential to produce marginally severe wind gusts
and perhaps a brief tornado, will be possible on Thursday along
parts of the central California Coast.
...California Coast...
A mid-level low and an associated trough over the eastern Pacific
will gradually approach the West Coast on Thursday. Ahead of the
trough, a stream of moisture will feed into California, where
scattered thunderstorms are expected to develop during the day. At
the surface, a front is forecast to move southward along the central
California coast. To the south of the front near the coast, surface
dewpoints will be in the 50s F. In addition, a 50 to 60 knot
low-level jet is forecast to be in proximity to the higher surface
dewpoints. This feature will create strong low-level shear along the
central California coast, where some forecast soundings have curved
hodographs and 0-3 km storm-relative helicity above 250 m2/s2. This
could support a marginal severe threat, with cells that rotate
within short line segments. A brief tornado or isolated severe wind
gust will be possible.
..Broyles.. 12/24/2025
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1241 AM CST Wed Dec 24 2025
Valid 251200Z - 261200Z
...Synopsis...
Upper ridging will persist across the central U.S. to some degree
tomorrow (Thursday), though some flattening of this ridge is
expected as the West Coast upper trough de-amplifies, with a
mid-level impulse poised to overspread the Rockies. As this occurs,
a surface low will develop over the central Plains, encouraging
locally stronger downslope flow along the central and southern High
Plains compared to previous days. 15-20 mph sustained westerly
surface winds are likely across much of the High Plains Thursday
afternoon. However, the latest guidance depicts relatively higher RH
compared to previous days (i.e. 20-30 percent RH across the southern
High Plains). Despite the locally higher RH, the persistent curing
of fuels and stronger surface wind field suggests that Elevated
highlights are warranted. These highlights have been introduced for
portions of far eastern New Mexico into the Texas Panhandle, where
RH is more likely to drop below 20 percent for at least a few hours
tomorrow.
..Squitieri.. 12/24/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1241 AM CST Wed Dec 24 2025
Valid 251200Z - 261200Z
...Synopsis...
Upper ridging will persist across the central U.S. to some degree
tomorrow (Thursday), though some flattening of this ridge is
expected as the West Coast upper trough de-amplifies, with a
mid-level impulse poised to overspread the Rockies. As this occurs,
a surface low will develop over the central Plains, encouraging
locally stronger downslope flow along the central and southern High
Plains compared to previous days. 15-20 mph sustained westerly
surface winds are likely across much of the High Plains Thursday
afternoon. However, the latest guidance depicts relatively higher RH
compared to previous days (i.e. 20-30 percent RH across the southern
High Plains). Despite the locally higher RH, the persistent curing
of fuels and stronger surface wind field suggests that Elevated
highlights are warranted. These highlights have been introduced for
portions of far eastern New Mexico into the Texas Panhandle, where
RH is more likely to drop below 20 percent for at least a few hours
tomorrow.
..Squitieri.. 12/24/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1233 AM CST Wed Dec 24 2025
Valid 241200Z - 251200Z
...Synopsis...
An upper ridge will prevail over the central U.S. while a mid-level
trough impinges on the Interior West today. Gradual strengthening of
the surface lee trough across the Plains will encourage modest dry
downslope flow across portions of the southern High Plains this
afternoon. 15 mph sustained westerly surface winds amid 15-20
percent RH will overlap with drying fuels over northeastern New
Mexico and southeastern Colorado, eastward into far southwestern
Kansas and the Texas Panhandle for a few hours this afternoon,
warranting Elevated highlights.
..Squitieri.. 12/24/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1233 AM CST Wed Dec 24 2025
Valid 241200Z - 251200Z
...Synopsis...
An upper ridge will prevail over the central U.S. while a mid-level
trough impinges on the Interior West today. Gradual strengthening of
the surface lee trough across the Plains will encourage modest dry
downslope flow across portions of the southern High Plains this
afternoon. 15 mph sustained westerly surface winds amid 15-20
percent RH will overlap with drying fuels over northeastern New
Mexico and southeastern Colorado, eastward into far southwestern
Kansas and the Texas Panhandle for a few hours this afternoon,
warranting Elevated highlights.
..Squitieri.. 12/24/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CST Tue Dec 23 2025
Valid 241200Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
CALIFORNIA AND THE CENTRAL VALLEY...
...SUMMARY...
Thunderstorms with marginally severe wind gusts, small hail and
potentially a brief tornado will be possible from Wednesday into
Wednesday night along parts of the California coast, and inland
across the San Joaquin Valley.
... Synopsis ...
A high-amplitude midlevel pattern will persist on Wednesday,
characterized by a deep trough across the eastern Pacific and a
building ridge across the Plains. This pattern will maintain a broad
belt of intense cyclonic flow across California into the Interior
West.
Throughout the day, an initial shortwave trough will continue
lifting northeast from the eastern Pacific into the Pacific
Northwest, while the attendant surface low lifts more northward
along the coast toward Washington. Late on Wednesday a second, more
potent trough will approach central and northern California --
primarily after dark. This setup will facilitate a prolonged period
rain and embedded thunderstorms across California and portions of
the Interior West into Thursday.
... California Coast ...
Strong ascent and strengthening onshore flow will aid in modest
destabilization Wednesday morning ahead of a surface cold front. An
ongoing band of convection is expected across the central and
southern coastal areas associated with the strongly forced ascent
along the advancing cold front. Given the presence of a strong
low-level jet (locally exceeding 50 knots at 1 km AGL), there is a
risk that these strong winds will mix to the surface within the
strongest convection resulting in damaging wind gusts. Forecast
soundings across the area do maintain some low-level curvature ahead
of the convective line, such that any convective element able to
interact with true surface-based buoyancy would have the potential
for a brief tornado.
In the wake of the morning convection, a secondary surface low will
intensify during the afternoon and overnight as it approaches the
northern California coast. This will likely trigger another round or
two of broken, low-topped convection along a second cold front.
Despite weaker instability than with the morning convection, the
strength of the wind fields would suggest an ongoing risk for
isolated wind damage as this convection moves inland.
... Central Valley ...
Cold midlevel temperatures and increasing height falls will
overspread surface dewpoints in the 40s to perhaps low 50s. Although
buoyancy will remain modest (MUCAPE at or below 500 J/kg), the
presence of a powerful midlevel jet in excess of 100 knots will
support long hodographs. This combination of modest instability and
large/long hodographs may support a threat for semi-organized
convection, including some potential for supercells. The strongest
storms will be capable of producing damaging gusts, hail, and a
brief tornado before the convection shifts east into the higher
terrain and weakens.
..Marsh/Squitieri.. 12/24/2025
Read more
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1153 PM CST Tue Dec 23 2025
Valid 241200Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL
CALIFORNIA AND THE CENTRAL VALLEY...
...SUMMARY...
Thunderstorms with marginally severe wind gusts, small hail and
potentially a brief tornado will be possible from Wednesday into
Wednesday night along parts of the California coast, and inland
across the San Joaquin Valley.
... Synopsis ...
A high-amplitude midlevel pattern will persist on Wednesday,
characterized by a deep trough across the eastern Pacific and a
building ridge across the Plains. This pattern will maintain a broad
belt of intense cyclonic flow across California into the Interior
West.
Throughout the day, an initial shortwave trough will continue
lifting northeast from the eastern Pacific into the Pacific
Northwest, while the attendant surface low lifts more northward
along the coast toward Washington. Late on Wednesday a second, more
potent trough will approach central and northern California --
primarily after dark. This setup will facilitate a prolonged period
rain and embedded thunderstorms across California and portions of
the Interior West into Thursday.
... California Coast ...
Strong ascent and strengthening onshore flow will aid in modest
destabilization Wednesday morning ahead of a surface cold front. An
ongoing band of convection is expected across the central and
southern coastal areas associated with the strongly forced ascent
along the advancing cold front. Given the presence of a strong
low-level jet (locally exceeding 50 knots at 1 km AGL), there is a
risk that these strong winds will mix to the surface within the
strongest convection resulting in damaging wind gusts. Forecast
soundings across the area do maintain some low-level curvature ahead
of the convective line, such that any convective element able to
interact with true surface-based buoyancy would have the potential
for a brief tornado.
In the wake of the morning convection, a secondary surface low will
intensify during the afternoon and overnight as it approaches the
northern California coast. This will likely trigger another round or
two of broken, low-topped convection along a second cold front.
Despite weaker instability than with the morning convection, the
strength of the wind fields would suggest an ongoing risk for
isolated wind damage as this convection moves inland.
... Central Valley ...
Cold midlevel temperatures and increasing height falls will
overspread surface dewpoints in the 40s to perhaps low 50s. Although
buoyancy will remain modest (MUCAPE at or below 500 J/kg), the
presence of a powerful midlevel jet in excess of 100 knots will
support long hodographs. This combination of modest instability and
large/long hodographs may support a threat for semi-organized
convection, including some potential for supercells. The strongest
storms will be capable of producing damaging gusts, hail, and a
brief tornado before the convection shifts east into the higher
terrain and weakens.
..Marsh/Squitieri.. 12/24/2025
Read more
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0653 PM CST Tue Dec 23 2025
Valid 240100Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL CALIFORNIA...
...SUMMARY...
An isolated threat for severe/damaging gusts and perhaps brief
tornadoes may develop late tonight/early Wednesday morning across
parts of coastal California.
... 01Z Update ...
A strong short-wave trough/surface low continues to approach the
California/Oregon coast. Later tonight a midlevel speed max will
intensify, helping to deepen the surface low, which will drive a
cold front eastward into California during the overnight and morning
hours. Despite limited buoyancy, especially surface based,
strengthening tropospheric flow and forced convection along the cold
front may support isolated damaging wind gusts along the California
coast. Should truly surface-based buoyancy develop and the forced
convection can realize this buoyancy, forecast wind profiles along
the coast exhibit sufficient deep-layer shear and low-level
curvature to support brief tornadoes. The easternmost extent of this
threat, especially across southern California, is delineated by the
expected position of the surface-cold front at 12Z/4AM PT. The
threat will continue past 12Z/4AM PT.
..Marsh.. 12/24/2025
Read more
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0653 PM CST Tue Dec 23 2025
Valid 240100Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL CALIFORNIA...
...SUMMARY...
An isolated threat for severe/damaging gusts and perhaps brief
tornadoes may develop late tonight/early Wednesday morning across
parts of coastal California.
... 01Z Update ...
A strong short-wave trough/surface low continues to approach the
California/Oregon coast. Later tonight a midlevel speed max will
intensify, helping to deepen the surface low, which will drive a
cold front eastward into California during the overnight and morning
hours. Despite limited buoyancy, especially surface based,
strengthening tropospheric flow and forced convection along the cold
front may support isolated damaging wind gusts along the California
coast. Should truly surface-based buoyancy develop and the forced
convection can realize this buoyancy, forecast wind profiles along
the coast exhibit sufficient deep-layer shear and low-level
curvature to support brief tornadoes. The easternmost extent of this
threat, especially across southern California, is delineated by the
expected position of the surface-cold front at 12Z/4AM PT. The
threat will continue past 12Z/4AM PT.
..Marsh.. 12/24/2025
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0340 PM CST Tue Dec 23 2025
Valid 251200Z - 311200Z
...Synopsis...
The expansive mid-level ridge across the central U.S. begins to move
eastward as a robust mid/upper level trough over the Northeast
Pacific continues to bring widespread rain and mountain snow to much
of the West. Persistent lee troughing under steady westerly flow
aloft should bring dry and breezy conditions on Day
3-5/Thursday-Saturday across portions of the southern High Plains
where record high temperatures are possible. The trough across the
West finally pushes deeper into Intermountain West by Day
5/Saturday, allowing fire weather concerns to linger across the
southern High Plains under an intensifying mid-level jet. A
mid-level trough deepens across the eastern U.S. early next week
ushering in a sweeping cold front that should reach the Gulf Coast
by Day 7/Monday. Dry post-frontal winds could increase fire concerns
across portions of the Southern Plains and Southeast in the Day
6-8/Sunday-Tuesday period where pockets of drier fuels exist and
minimal rainfall is expected.
...Day 3-5/Thursday-Saturday...
Anomalously warm temperatures in the 70s and 80s under a persistent
mid-level ridge will continue to dry fuels across the central and
southern High Plains through this week. Surface lee troughing across
the Plains along with downslope drying and enhanced west-southwest
winds should present an ongoing fire weather threat across portions
of far eastern NM, TX Panhandle and far western OK. Increasing
cloud cover and surface dewpoints across the southern High Plains
could inhibit boundary layer mixing on Day 3/Thursday, limiting RH
reductions and mitigating a more widespread critical fire weather
event for the TX Panhandle. Drier conditions and lower daytime
relative humidity should return to the region Day
4-5/Friday-Saturday coinciding with enhanced southwest surface winds
under deep layer west-southwest flow. 40 percent critical
probabilities remain for portions of the TX Panhandle vicinity on
Day 4/Friday and were similarly added on Day 5/Saturday.
...Day 6-8/Sunday-Tuesday...
A cold front sweeping through the eastern U.S. should be the primary
focus for fire weather threats early next week. However, latest
model guidance suggests expansive cloud cover and potential rainfall
along and behind the front which could mitigate fire weather
concerns within the dry post frontal regime.
..Williams.. 12/23/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0340 PM CST Tue Dec 23 2025
Valid 251200Z - 311200Z
...Synopsis...
The expansive mid-level ridge across the central U.S. begins to move
eastward as a robust mid/upper level trough over the Northeast
Pacific continues to bring widespread rain and mountain snow to much
of the West. Persistent lee troughing under steady westerly flow
aloft should bring dry and breezy conditions on Day
3-5/Thursday-Saturday across portions of the southern High Plains
where record high temperatures are possible. The trough across the
West finally pushes deeper into Intermountain West by Day
5/Saturday, allowing fire weather concerns to linger across the
southern High Plains under an intensifying mid-level jet. A
mid-level trough deepens across the eastern U.S. early next week
ushering in a sweeping cold front that should reach the Gulf Coast
by Day 7/Monday. Dry post-frontal winds could increase fire concerns
across portions of the Southern Plains and Southeast in the Day
6-8/Sunday-Tuesday period where pockets of drier fuels exist and
minimal rainfall is expected.
...Day 3-5/Thursday-Saturday...
Anomalously warm temperatures in the 70s and 80s under a persistent
mid-level ridge will continue to dry fuels across the central and
southern High Plains through this week. Surface lee troughing across
the Plains along with downslope drying and enhanced west-southwest
winds should present an ongoing fire weather threat across portions
of far eastern NM, TX Panhandle and far western OK. Increasing
cloud cover and surface dewpoints across the southern High Plains
could inhibit boundary layer mixing on Day 3/Thursday, limiting RH
reductions and mitigating a more widespread critical fire weather
event for the TX Panhandle. Drier conditions and lower daytime
relative humidity should return to the region Day
4-5/Friday-Saturday coinciding with enhanced southwest surface winds
under deep layer west-southwest flow. 40 percent critical
probabilities remain for portions of the TX Panhandle vicinity on
Day 4/Friday and were similarly added on Day 5/Saturday.
...Day 6-8/Sunday-Tuesday...
A cold front sweeping through the eastern U.S. should be the primary
focus for fire weather threats early next week. However, latest
model guidance suggests expansive cloud cover and potential rainfall
along and behind the front which could mitigate fire weather
concerns within the dry post frontal regime.
..Williams.. 12/23/2025
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0145 PM CST Tue Dec 23 2025
Valid 232000Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL CALIFORNIA...
...SUMMARY...
An isolated threat for severe/damaging gusts and perhaps a brief
tornado may develop late tonight/early Wednesday morning across
parts of coastal California.
...20Z Update...
Relatively minor adjustments to the general thunder forecast were
made based on the latest observations and model guidance. The
remainder of the forecast remains unchanged. See the previous
discussion for additional information.
..Wendt.. 12/23/2025
.PREV DISCUSSION... /ISSUED 1020 AM CST Tue Dec 23 2025/
...California...
Within large-scale upper troughing over the eastern Pacific, an
embedded mid-level shortwave trough will move quickly eastward and
approach the CA Coast late tonight/early Wednesday morning. A
corresponding strengthening and increase in the flow through much of
the troposphere is anticipated late in the period, with a surface
low also forecast to deepen along/near the coast of northern CA. A
cold front attendant to this surface low will sweep quickly
eastward, and should be approaching/onshore across parts of coastal
northern/central CA by 12Z early Wednesday morning. Current
expectations are for the thermodynamic profile to remain mostly
saturated, with poor lapse rates generally limiting instability.
Even so, it appears that a gradual increase in low-level moisture
ahead of the cold front and slightly cooling mid-level temperatures
with the approach of the shortwave trough may support weak but
sufficient MUCAPE for an organized band of low-topped thunderstorms
late tonight.
Most guidance suggests this convection will not impact parts of
coastal CA until after 24/06Z, and there is still significant
uncertainty whether enough boundary-layer instability will be
present to support surface-based convection. There is also a signal
for pre-frontal convection in the low-level warm advection regime
across parts of central into coastal southern CA. Given the strength
of the low/mid-level flow forecast, and related strong
low-level/deep-layer shear, it appears that convectively enhanced
winds may be capable of reaching severe levels and producing damage
on an isolated basis even if instability remains minimal. A brief
tornado may also occur if convection can become truly surface based,
as effective SRH will be enhanced by a 50-70 kt southerly low-level
jet. Based on latest guidance trends, the Marginal Risk has been
expanded southward along the coast to include more of
central/southern CA. This isolated severe threat is expected to
continue beyond 12Z Wednesday into the Day 2 period.
Read more
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0124 PM CST Tue Dec 23 2025
Valid 241200Z - 251200Z
Modest west-southwest flow aloft along with a deepening lee trough
in the High Plains will promote breezy west-southwest winds across
the Southern Plains Wednesday. A drier air mass aided by the
downslope regime will be in place across the central and southern
High Plains Wednesday, demarcated by a considerably more moist
boundary layer farther east from central TX into central OK. The
most favorable alignment of southwest sustained winds of 15 mph,
minimum relative humidity as low as 10% and receptive fuels is
expected across the TX/OK Panhandles and adjacent high plains areas
of NM and CO. Only slight modifications were necessary to the
existing Elevated highlights based on latest model guidance.
..Williams.. 12/23/2025
.PREV DISCUSSION... /ISSUED 0118 AM CST Tue Dec 23 2025/
...Synopsis...
A mid-level ridge will persist across the central U.S., with a
highly amplified mid-level trough poised to gradually drift eastward
across the Interior West tomorrow (Wednesday). Lee troughing across
the High Plains will intensify through the day, promoting a modestly
stronger surface wind field across the southern High Plains compared
to Day 1. 15 mph sustained westerly surface winds will coincide with
15-20 percent RH during the afternoon across northeast New Mexico
into the Texas Panhandle and far southwestern Kansas. Given dry
fuels over this region, Elevated highlights have been introduced.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0122 PM CST Tue Dec 23 2025
Valid 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
COASTAL CALIFORNIA...
...SUMMARY...
Thunderstorms with marginally severe wind gusts and perhaps a brief
tornado, will be possible on Thursday along parts of the central and
southern California Coast.
...California...
Large-scale mid-level troughing is forecast to persist across the CA
coast and move onshore Thursday and Thursday night. Within the
broader trough, several embedded impulses will move onshore within
strong southwesterly mid-level flow. One of these stronger impulses
will start the day moving onshore over northern CA before quickly
lifting north into southern OR. A strong surface low and cold front
associated with this impulse will move quickly toward the coast
prior to 12z Thursday. A band of low-topped storms along the front
may be ongoing at the start of the forecast period, and persist for
a few hours Thursday morning. Confidence in sufficient buoyancy for
a sustained severe threat farther inland is low. Still, strong low
to mid-level flow and modestly steep low-level lapse rates could
support isolated severe wind gusts and perhaps a brief tornado early
along the coast.
The severe threat will likely shift southeastward toward southern CA
coast through the day as a second mid-level impulse and the main
core of the upper trough approach. Strong onshore flow and
persistent low-level moisture transport will allow for weak
destabilization near the coast during the afternoon and continuing
into the evening. 90+ kt of mid-level flow and locally enlarged
hodographs could allow for occasional stronger storms capable of
damaging gusts or a brief tornado despite the weak buoyancy.
..Lyons.. 12/23/2025
Read more
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1124 AM CST Tue Dec 23 2025
Valid 241200Z - 251200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
COASTAL CALIFORNIA AND THE CENTRAL VALLEY...
...SUMMARY...
Thunderstorms with marginally severe wind gusts, small hail and
potentially a brief tornado will be possible from Wednesday into
Wednesday night along parts of the California coast, and inland
across the San Joaquin Valley.
...California Coast...
West of an imposing upper ridge building over the central US, deep
troughing will intensify Wednesday and Wednesday night over the
eastern Pacific. Several embedded disturbances will track onshore
over parts of the West Coast. Strong ascent and strengthening
onshore flow will aid in modest destabilization, first near the
southern CA coast/LA Basin and eventually farther north and inland.
A band of storms will likely be ongoing over southern CA and
adjacent waters early Wednesday morning. Strong flow aloft (1km AGL
wind 50+ kt) may mix to the surface supporting strong gusts and the
potential for a brief tornado. A second more potent shortwave and
surface low (sub 985 mb) will intensify and move near the
central/northern CA Coast into early Thursday. A broken, low-topped
band of storms along the advancing cold front may eventually move
onshore overnight with a risk for occasional strong gusts.
...San Joaquin Valley...
Across central CA, cold mid-level temperatures (-24 to -27 C),
strong height falls and the left exit of a 100+ kt mid-level jet
will overspread 50s F surface dewpoints across the northern and
central San Joaquin Valley Wednesday afternoon and evening. Model
soundings show modest MUCAPE (max around 500 J/kg) amid veering wind
profiles and enlarged hodographs. Despite the limited buoyancy, a
few semi-organized supercells are possible. Damaging gusts, hail and
a brief tornado are possible with the strongest storms before
convection gradually moves eastward into the higher terrain and
weakens.
..Lyons.. 12/23/2025
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1025 AM CST Tue Dec 23 2025
Valid 231700Z - 241200Z
...NO CRITICAL AREAS...
No changes to the Day 1 Fire Weather Outlook with minimal fire
weather concerns across CONUS. Upper-level ridging over the central
U.S., extending well into southwestern Canadian provinces, will
continue to promote well above normal temperatures across much of
the central/southern U.S. into the Intermountain West. Dry
conditions remain across the central and southern High Plains with
relative humidity dropping into the 15-20% range early this
afternoon amid moderately dry fuels. However, weak wind fields
within diffuse surface pressure gradients across the region should
mitigate a broader fire weather concern. Dry, downslope flow along
the CO Front Range and leeward sides of the Sangre de Cristo
Mountains under modest west-southwest flow aloft is expected through
the afternoon. However, a lack of more intense surface lee troughing
should limit a larger scale wind event.
..Williams.. 12/23/2025
.PREV DISCUSSION... /ISSUED 0118 AM CST Tue Dec 23 2025/
...Synopsis...
Upper ridging will remain in place east of the Rockies while a
highly amplified mid-level trough impinges on the West Coast today.
Surface lee troughing will encourage moisture return across the
Plains states, with relatively drier air meandering along the
immediate lee of the Rockies. Surface winds along the southern into
central High Plains will be relatively weak on a large-scale basis
though, with wildfire-spread concerns remaining localized at best.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1025 AM CST Tue Dec 23 2025
Valid 231700Z - 241200Z
...NO CRITICAL AREAS...
No changes to the Day 1 Fire Weather Outlook with minimal fire
weather concerns across CONUS. Upper-level ridging over the central
U.S., extending well into southwestern Canadian provinces, will
continue to promote well above normal temperatures across much of
the central/southern U.S. into the Intermountain West. Dry
conditions remain across the central and southern High Plains with
relative humidity dropping into the 15-20% range early this
afternoon amid moderately dry fuels. However, weak wind fields
within diffuse surface pressure gradients across the region should
mitigate a broader fire weather concern. Dry, downslope flow along
the CO Front Range and leeward sides of the Sangre de Cristo
Mountains under modest west-southwest flow aloft is expected through
the afternoon. However, a lack of more intense surface lee troughing
should limit a larger scale wind event.
..Williams.. 12/23/2025
.PREV DISCUSSION... /ISSUED 0118 AM CST Tue Dec 23 2025/
...Synopsis...
Upper ridging will remain in place east of the Rockies while a
highly amplified mid-level trough impinges on the West Coast today.
Surface lee troughing will encourage moisture return across the
Plains states, with relatively drier air meandering along the
immediate lee of the Rockies. Surface winds along the southern into
central High Plains will be relatively weak on a large-scale basis
though, with wildfire-spread concerns remaining localized at best.
...Please see www.spc.noaa.gov/fire for graphic product...
Read more
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1020 AM CST Tue Dec 23 2025
Valid 231630Z - 241200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
COASTAL CALIFORNIA...
...SUMMARY...
An isolated threat for severe/damaging gusts and perhaps a brief
tornado may develop late tonight/early Wednesday morning across
parts of coastal California.
...California...
Within large-scale upper troughing over the eastern Pacific, an
embedded mid-level shortwave trough will move quickly eastward and
approach the CA Coast late tonight/early Wednesday morning. A
corresponding strengthening and increase in the flow through much of
the troposphere is anticipated late in the period, with a surface
low also forecast to deepen along/near the coast of northern CA. A
cold front attendant to this surface low will sweep quickly
eastward, and should be approaching/onshore across parts of coastal
northern/central CA by 12Z early Wednesday morning. Current
expectations are for the thermodynamic profile to remain mostly
saturated, with poor lapse rates generally limiting instability.
Even so, it appears that a gradual increase in low-level moisture
ahead of the cold front and slightly cooling mid-level temperatures
with the approach of the shortwave trough may support weak but
sufficient MUCAPE for an organized band of low-topped thunderstorms
late tonight.
Most guidance suggests this convection will not impact parts of
coastal CA until after 24/06Z, and there is still significant
uncertainty whether enough boundary-layer instability will be
present to support surface-based convection. There is also a signal
for pre-frontal convection in the low-level warm advection regime
across parts of central into coastal southern CA. Given the strength
of the low/mid-level flow forecast, and related strong
low-level/deep-layer shear, it appears that convectively enhanced
winds may be capable of reaching severe levels and producing damage
on an isolated basis even if instability remains minimal. A brief
tornado may also occur if convection can become truly surface based,
as effective SRH will be enhanced by a 50-70 kt southerly low-level
jet. Based on latest guidance trends, the Marginal Risk has been
expanded southward along the coast to include more of
central/southern CA. This isolated severe threat is expected to
continue beyond 12Z Wednesday into the Day 2 period.
..Gleason/Thornton.. 12/23/2025
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