SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0653 AM CST Sun Dec 21 2025
Valid 211300Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Discussion...
A progressive/zonal upper-flow pattern will continue over the CONUS.
A low-amplitude shortwave trough will move inland across the Pacific
Northwest by tonight. Weak buoyancy and cooling temperatures aloft
may become sufficient for isolated lightning flashes, particularly
near the Washington coast. Farther south, a moisture-rich plume and
a marginally favorable thermodynamic environment may allow for some
lighting flashes across northern California.
Elsewhere, a relatively moist airmass near/south of a
southward-moving front, along with continued weak warm/moist
advection, will probably be conducive for isolated thunderstorms
mainly across southern portions of Louisiana and Mississippi today.
..Guyer/Marsh.. 12/21/2025
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SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0653 AM CST Sun Dec 21 2025
Valid 211300Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Discussion...
A progressive/zonal upper-flow pattern will continue over the CONUS.
A low-amplitude shortwave trough will move inland across the Pacific
Northwest by tonight. Weak buoyancy and cooling temperatures aloft
may become sufficient for isolated lightning flashes, particularly
near the Washington coast. Farther south, a moisture-rich plume and
a marginally favorable thermodynamic environment may allow for some
lighting flashes across northern California.
Elsewhere, a relatively moist airmass near/south of a
southward-moving front, along with continued weak warm/moist
advection, will probably be conducive for isolated thunderstorms
mainly across southern portions of Louisiana and Mississippi today.
..Guyer/Marsh.. 12/21/2025
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0320 AM CST Sun Dec 21 2025
Valid 241200Z - 291200Z
...DISCUSSION...
Medium-range model guidance initially shows a pattern featuring an
upper ridge over the central CONUS and trough along the West Coast,
transitioning to a more progressive flow regime and lowering heights
across the Great Plains during the Thursday-Saturday (D5-D7) period.
The inland-moving West Coast trough will potentially yield isolated
to scattered thunderstorms on Wednesday into early Thursday over
portions of southern and central CA and perhaps a localized risk for
a couple of stronger thunderstorms. Details concerning this
convective scenario and overall magnitude of severe risk preclude
severe highlights. Farther east, some moisture return northward
into the southern Great Plains and MS Valley through Friday will
likely be modulated by frontal advancements during the latter part
of extended period.
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SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0209 AM CST Sun Dec 21 2025
Valid 231200Z - 241200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast across the contiguous United
States on Tuesday or Tuesday night.
...Synopsis...
A dominant mid- to upper-level ridge will remain steadfast across
central portion of the Lower 48 states. An upper trough will
encroach on the West Coast, and a lead mid-level trough will move
quickly northeast from the eastern Pacific into the northern CA
coastal area late Tuesday night. Scant to weak buoyancy will
gradually develop Tuesday night in the vicinity of the CA coast and
coastal range from near Point Conception to near the OR border.
Scattered showers and isolated thunderstorms will gradually spread
inland concurrent with increasing large-scale forcing and
instability. Some forecast soundings depict a deep,
lower-tropospheric moist layer co-located with intense low-level
shear, which could imply storm organization being possible with the
strongest low-topped storms. Uncertainty is high at this time for
such a scenario given appreciable model variability. Farther east,
a weak upper trough near the lower Rio Grande Valley will undercut a
mid- to upper-level ridge over the central US. Weak convection is
possible in association with this upper feature, but confidence in
attaining 10-percent thunderstorm probabilities is low at this time.
..Smith.. 12/21/2025
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SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0209 AM CST Sun Dec 21 2025
Valid 231200Z - 241200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast across the contiguous United
States on Tuesday or Tuesday night.
...Synopsis...
A dominant mid- to upper-level ridge will remain steadfast across
central portion of the Lower 48 states. An upper trough will
encroach on the West Coast, and a lead mid-level trough will move
quickly northeast from the eastern Pacific into the northern CA
coastal area late Tuesday night. Scant to weak buoyancy will
gradually develop Tuesday night in the vicinity of the CA coast and
coastal range from near Point Conception to near the OR border.
Scattered showers and isolated thunderstorms will gradually spread
inland concurrent with increasing large-scale forcing and
instability. Some forecast soundings depict a deep,
lower-tropospheric moist layer co-located with intense low-level
shear, which could imply storm organization being possible with the
strongest low-topped storms. Uncertainty is high at this time for
such a scenario given appreciable model variability. Farther east,
a weak upper trough near the lower Rio Grande Valley will undercut a
mid- to upper-level ridge over the central US. Weak convection is
possible in association with this upper feature, but confidence in
attaining 10-percent thunderstorm probabilities is low at this time.
..Smith.. 12/21/2025
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0132 AM CST Sun Dec 21 2025
Valid 221200Z - 231200Z
...Synopsis...
Upper ridging will persist over the CONUS tomorrow (Monday), with
surface lee troughing continuing over the Plains states. Dry
downslope flow is expected across the southern High Plains, with
15-20 percent RH becoming common over most locales as the boundary
layer mixes Monday afternoon. Guidance consensus depicts a corridor
of 15+ mph sustained westerly surface winds overlapping the
aforementioned RH for several hours Monday afternoon across eastern
New Mexico into the Texas Panhandle. Elevated highlights are
warranted for these conditions given the presence of dry fuels.
..Squitieri.. 12/21/2025
...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
0132 AM CST Sun Dec 21 2025
Valid 221200Z - 231200Z
...Synopsis...
Upper ridging will persist over the CONUS tomorrow (Monday), with
surface lee troughing continuing over the Plains states. Dry
downslope flow is expected across the southern High Plains, with
15-20 percent RH becoming common over most locales as the boundary
layer mixes Monday afternoon. Guidance consensus depicts a corridor
of 15+ mph sustained westerly surface winds overlapping the
aforementioned RH for several hours Monday afternoon across eastern
New Mexico into the Texas Panhandle. Elevated highlights are
warranted for these conditions given the presence of dry fuels.
..Squitieri.. 12/21/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0131 AM CST Sun Dec 21 2025
Valid 211200Z - 221200Z
...NO CRITICAL AREAS...
...Synopsis...
Upper ridging will build over the CONUS, resulting in surface high
pressure overspreading the eastern CONUS as a surface trough becomes
established over the Plains today. Relatively cool and/or moist
conditions will prevail over most locales east of the Rockies,
limiting the potential for significant wildfire spread.
..Squitieri.. 12/21/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0131 AM CST Sun Dec 21 2025
Valid 211200Z - 221200Z
...NO CRITICAL AREAS...
...Synopsis...
Upper ridging will build over the CONUS, resulting in surface high
pressure overspreading the eastern CONUS as a surface trough becomes
established over the Plains today. Relatively cool and/or moist
conditions will prevail over most locales east of the Rockies,
limiting the potential for significant wildfire spread.
..Squitieri.. 12/21/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1235 AM CST Sun Dec 21 2025
Valid 221200Z - 231200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast on Monday.
...Synopsis...
Model guidance continues to show an upper-level ridge and quiescent
conditions influencing weather across much of Lower 48 states on
Monday. A mid-level shortwave trough will move from the eastern
Pacific into WA and British Columbia during the period.
Increasingly cool mid-level temperatures will support pockets of
scant instability near the Pacific Northwest coast. Widely
scattered showers and perhaps a few low-topped thunderstorms may
develop along the immediate coast. Farther southeast along the
lower coast of TX within a seasonably moist airmass, weak convection
may develop but negligible forcing will likely limit convective
potential with this activity.
..Smith.. 12/21/2025
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SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1235 AM CST Sun Dec 21 2025
Valid 221200Z - 231200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not forecast on Monday.
...Synopsis...
Model guidance continues to show an upper-level ridge and quiescent
conditions influencing weather across much of Lower 48 states on
Monday. A mid-level shortwave trough will move from the eastern
Pacific into WA and British Columbia during the period.
Increasingly cool mid-level temperatures will support pockets of
scant instability near the Pacific Northwest coast. Widely
scattered showers and perhaps a few low-topped thunderstorms may
develop along the immediate coast. Farther southeast along the
lower coast of TX within a seasonably moist airmass, weak convection
may develop but negligible forcing will likely limit convective
potential with this activity.
..Smith.. 12/21/2025
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1114 PM CST Sat Dec 20 2025
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Pacific Northwest...
Low-amplitude short-wave trough is forecast to approach the Pacific
Northwest coast later this evening as modest midlevel height falls
spread inland across WA/OR. Latest model guidance suggests weak
buoyancy will persist much of the period, particularly near the
coast, where onshore flow will contribute to SBCAPE generally less
than 100 J/kg. As freezing levels lower, shallow convection may
penetrate levels necessary for lightning discharge. For these
reasons will maintain 10% probability for isolated thunderstorms,
primarily near the coast.
..Darrow/Squitieri.. 12/21/2025
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1114 PM CST Sat Dec 20 2025
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Pacific Northwest...
Low-amplitude short-wave trough is forecast to approach the Pacific
Northwest coast later this evening as modest midlevel height falls
spread inland across WA/OR. Latest model guidance suggests weak
buoyancy will persist much of the period, particularly near the
coast, where onshore flow will contribute to SBCAPE generally less
than 100 J/kg. As freezing levels lower, shallow convection may
penetrate levels necessary for lightning discharge. For these
reasons will maintain 10% probability for isolated thunderstorms,
primarily near the coast.
..Darrow/Squitieri.. 12/21/2025
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SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1114 PM CST Sat Dec 20 2025
Valid 211200Z - 221200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
Severe thunderstorms are not expected today.
...Pacific Northwest...
Low-amplitude short-wave trough is forecast to approach the Pacific
Northwest coast later this evening as modest midlevel height falls
spread inland across WA/OR. Latest model guidance suggests weak
buoyancy will persist much of the period, particularly near the
coast, where onshore flow will contribute to SBCAPE generally less
than 100 J/kg. As freezing levels lower, shallow convection may
penetrate levels necessary for lightning discharge. For these
reasons will maintain 10% probability for isolated thunderstorms,
primarily near the coast.
..Darrow/Squitieri.. 12/21/2025
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0633 PM CST Sat Dec 20 2025
Valid 210100Z - 211200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few lightning flashes may occur late tonight over southern
Louisiana; however, this activity will be very sparse.
...01z Update...
Weak surface front is expected to settle into northern LA, arcing
southwest into the Hill Country of central TX by the end of the
period. Favorable low-level trajectories will continue across the
western Gulf basin into southern LA tonight where 60s surface dew
points are expected to hold. However, large-scale forcing is not
expected to be particularly notable and a fairly strong cap is
currently noted around 2km on the 00z LCH sounding. Latest model
guidance suggests this capping will likely persist, but possibly
weaken toward 12z. If so, a few flashes of lightning may accompany
weak convection across southern LA.
..Darrow.. 12/21/2025
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SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0633 PM CST Sat Dec 20 2025
Valid 210100Z - 211200Z
...NO SEVERE THUNDERSTORM AREAS FORECAST...
...SUMMARY...
A few lightning flashes may occur late tonight over southern
Louisiana; however, this activity will be very sparse.
...01z Update...
Weak surface front is expected to settle into northern LA, arcing
southwest into the Hill Country of central TX by the end of the
period. Favorable low-level trajectories will continue across the
western Gulf basin into southern LA tonight where 60s surface dew
points are expected to hold. However, large-scale forcing is not
expected to be particularly notable and a fairly strong cap is
currently noted around 2km on the 00z LCH sounding. Latest model
guidance suggests this capping will likely persist, but possibly
weaken toward 12z. If so, a few flashes of lightning may accompany
weak convection across southern LA.
..Darrow.. 12/21/2025
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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0437 PM CST Sat Dec 20 2025
Valid 221200Z - 281200Z
...Synopsis...
Increasing mid to upper-level heights are expected over the central
and southern CONUS by early next week as a ridge migrates eastward
over Chihuahua Mexico and into the Southern Plains. This ridge will
continue to drift eastward through mid to late next week over the
Gulf, while troughing begins to impact the Pacific Northwest.
Persistent west to southwest mid-level flow across the Rockies will
aid in lee troughing throughout next week, and the potential for
some breezy winds at the surface across the Central and Southern
High Plains.
...Southern High Plains...
Breezy westerly downslope winds are expected to impact the TX and OK
Panhandles and east-central NM by Monday/D3. Low critical
probabilities will remain in the forecast here, though there are
some indications of only locally critical RH being reached.
Decreasing surface wind speeds will accompany a decreasing surface
pressure gradient Tuesday/D4 across this same region. By
Wednesday/D5, however, increasing downslope flow will return as a
lee trough deepens. This stronger surface flow will likely be more
confined to the northwestern/western TX/OK Panhandles and far
northeastern NM, where low critical probabilities remain in place
from the previous forecast. In addition, fuels across this landscape
will become more receptive to fire start/spread with very little to
no sign of appreciable precipitation and above average
temperatures/low relative humidity anticipated through the extended
forecast.
..Barnes.. 12/20/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0437 PM CST Sat Dec 20 2025
Valid 221200Z - 281200Z
...Synopsis...
Increasing mid to upper-level heights are expected over the central
and southern CONUS by early next week as a ridge migrates eastward
over Chihuahua Mexico and into the Southern Plains. This ridge will
continue to drift eastward through mid to late next week over the
Gulf, while troughing begins to impact the Pacific Northwest.
Persistent west to southwest mid-level flow across the Rockies will
aid in lee troughing throughout next week, and the potential for
some breezy winds at the surface across the Central and Southern
High Plains.
...Southern High Plains...
Breezy westerly downslope winds are expected to impact the TX and OK
Panhandles and east-central NM by Monday/D3. Low critical
probabilities will remain in the forecast here, though there are
some indications of only locally critical RH being reached.
Decreasing surface wind speeds will accompany a decreasing surface
pressure gradient Tuesday/D4 across this same region. By
Wednesday/D5, however, increasing downslope flow will return as a
lee trough deepens. This stronger surface flow will likely be more
confined to the northwestern/western TX/OK Panhandles and far
northeastern NM, where low critical probabilities remain in place
from the previous forecast. In addition, fuels across this landscape
will become more receptive to fire start/spread with very little to
no sign of appreciable precipitation and above average
temperatures/low relative humidity anticipated through the extended
forecast.
..Barnes.. 12/20/2025
...Please see www.spc.noaa.gov/fire for graphic product...
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