SPC Dec 4, 2025 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1149 PM CST Wed Dec 03 2025

Valid 041200Z - 051200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not forecast in the U.S. today or tonight.

...DISCUSSION...
Across the U.S. today, mid-level flow will remain northwesterly in
the western states as a trough moves through the Great Plains.
West-southwesterly flow aloft will be in place across the Southeast.
At the surface, a moist airmass will be located over the western and
central Gulf. Isolated to scattered thunderstorms will be possible
along the northern edge of the moist airmass along parts of the
western and central Gulf Coast, and further north into the lower
Sabine and lower Mississippi River Valleys. Low-level moisture and
instability is expected to be insufficient for severe storms.
Elsewhere across the continental U.S., thunderstorms are not
forecast today or tonight.

..Broyles/Weinman.. 12/04/2025


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SPC Dec 4, 2025 0100 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 0100Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0650 PM CST Wed Dec 03 2025

Valid 040100Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
UPPER TEXAS AND SOUTHWEST LOUISIANA COASTS...

...SUMMARY...
A storm with isolated severe hail will be possible tonight along the
upper Texas and southwest Louisiana coasts.

...Upper Texas and Southwest Louisiana Coasts...
Water vapor imagery shows a trough over the Desert Southwest with
west-southwesterly flow located across much of the southern U.S. At
the surface, a moist airmass is located over much of the western
Gulf. The northern edge of the moist airmass impinges the middle
Texas Coast, and model forecasts suggest that the airmass will
gradually shift northeastward along the upper Texas into far
southwest Louisiana. Although warm-advection-related thunderstorms
will be mostly concentrated offshore, an isolated strong storm with
hail potential could develop in far southeast Texas or far southwest
Louisiana from late evening into the overnight period.

..Broyles.. 12/04/2025


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SPC Dec 3, 2025 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1017 AM CST Wed Dec 03 2025

Valid 031630Z - 041200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PORTIONS OF THE
UPPER TX GULF COAST INTO FAR SOUTHWEST LOUISIANA...

...SUMMARY...
Thunderstorms will be possible this evening into tonight across the
western Gulf Coast states. Severe storms are not expected.

...Synopsis...
A mid-level wave traversing the Four Corners region as of
mid-morning is forecast to move eastward into the southern Plains
through early Thursday morning. West/southwesterly mid-level flow
will steadily increase to around 50-60 knots as the wave approaches,
which will help advect a plume of modestly steep (7 to 7.5 C/km)
lapse rates out of northern Mexico towards the TX/LA Gulf Coast
region through tonight. At the surface, a weak surface low noted off
the south TX coast will gradually intensify and lift northward
towards the LA coast as broad-scale ascent ahead of the upper wave
increases later tonight. The combination of increasing ascent and
steepening lapse rates will support isolated to scattered
thunderstorms tonight into early Thursday morning for much of the TX
Coastal Plain and central to southern LA.

...Upper TX Gulf Coast to far southwest LA...
Isolated to scattered thunderstorms are expected to develop along
the upper TX Gulf Coast around 02-04 UTC tonight as warm advection
atop a residual frontal boundary increases. Forecast consensus is
that the surface low will remain off the coast through the forecast
period, which will limit the potential for surface-based convection.
However, strong moistening/ascent within the 925-850 mb layer will
likely support a narrow swath of deep convection along the TX coast
where MUCAPE may exceed 1000 J/kg. Within this zone, buoyancy
profiles should be deep enough to realize the favorable kinematic
environment, which will be characterized by elongated hodographs and
effective shear of around 50 knots. Destructive storm
interactions/modes will likely modulate the overall longevity of any
particular cell, but the sufficient thermodynamic/kinematic
environment may support a few brief strong/severe storms capable of
small to severe hail.

..Moore.. 12/03/2025


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SPC Dec 3, 2025 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0656 AM CST Wed Dec 03 2025

Valid 031300Z - 041200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms will be possible this evening into tonight across the
western Gulf Coast states. Severe storms are not expected.

...East/Southeast TX into Central/Southern LA...
Early-morning satellite imagery shows a well-defined southern-stream
shortwave trough progressing southeastward along the southern CA/NV
border vicinity. This shortwave is forecast to continue
southeastward through the Lower CO River Valley region before then
pivoting more eastward across the Southwest. An extended fetch of
mid-level southwesterly flow preceding this wave is expected to
strengthen as it moves across the Southwest. At the same time,
southerly low-level flow across the western Gulf will strengthen,
with an attendant increase in warm-air advection from the western
Gulf across the TX Coast into LA. This warm-air advection will help
support modest buoyancy atop a shallow stable layer, promoting
elevated thunderstorms from east/southeast TX into central and
southern LA.

Thunderstorm coverage is forecast to quickly increase in the 03Z to
04Z time frame across southeast TX before spreading eastward and
northeastward throughout the remainder of the period. Moderate to
strong southwesterly mid-level flow will extend across this entire
region, supporting strong deep-layer shear. This strong shear could
support some occasionally stronger/more organized updrafts capable
of small hail. Even so, weak buoyancy should limit updraft strength
and duration, keeping any hail threat minimal. Mid 60s dewpoints may
advect onto the immediate middle and upper TX coast as a weak
surface low moves northeastward through the region. However, even
with these higher dewpoints, surface-based convective inhibition
will likely prevail given deep warm layer anticipated. This should
keep the tornado potential very low, despite substantial low-level
storm-relative helicity.

..Mosier/Jewell.. 12/03/2025


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