SPC Nov 28, 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
0645 PM CST Thu Nov 27 2025

Valid 280100Z - 281200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for thunderstorms appears negligible across much of the
nation tonight.

...01Z Update...
Drying and stabilizing trends are now well underway across
southeastern Florida coastal areas and the Keys, where
lower/mid-tropospheric wind fields have veered to northwesterly.

Some lightning was noted earlier in a convective band within
west-southwesterly low-level flow emanating from Lake Ontario, where
trajectories across the relatively warm lake waters are maximized.
Additional convection occasionally becoming capable of producing
lightning appears possible to the east of Lake Ontario through at
least 05-06Z, before this potential becomes more negligible as mean
lower/mid-tropospheric winds begin to veer to a more
westerly/northwesterly component.

..Kerr.. 11/28/2025


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SPC Nov 27, 2025 2000 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 2000Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0139 PM CST Thu Nov 27 2025

Valid 272000Z - 281200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Organized severe thunderstorms are not forecast through tonight.

...20z Update...
Only minor adjustments were made to the thunder line to account for
ongoing trends across the Florida peninsula. Otherwise, no
additional changes are needed. See previous discussion for more
information.

..Thornton.. 11/27/2025

.PREV DISCUSSION... /ISSUED 1020 AM CST Thu Nov 27 2025/

...Synopsis and Discussion...
A large-scale upper trough encompassing much of the central/eastern
CONUS will develop slowly eastward through the period. Isolated
thunderstorm potential today will generally remain limited to parts
of south FL and the Keys along/ahead of a southward-moving cold
front. 11/12Z soundings from XMR/TBW/KEY show southwesterly winds
strengthening with height at mid/upper levels. While sufficient
deep-layer shear may exist to support a stronger thunderstorm or two
this afternoon, especially along the Atlantic Coast in south FL, the
presence of poor mid-level lapse rates and weak low-level winds
should hinder the risk for organized severe thunderstorms over land.
Isolated lightning flashes may also occur with snow bands occurring
in western NY off of Lake Ontario.


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SPC Nov 27, 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
0647 AM CST Thu Nov 27 2025

Valid 271300Z - 281200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not anticipated today.

...FL...
A large upper trough remains dominant over the eastern U.S. today,
with a cold front sweeping southward across FL. A few thunderstorms
will be possible over central/south FL through the afternoon, but
low-level drying will eventually stabilize the air mass and end the
convective threat after dark.

...PA/NY...
Cold temperatures aloft and warm lake temperatures could be
sufficient for a few lightning strikes in the lee of Lake Erie and
Ontario today. Forecast soundings suggest mid-level lapse rates and
the depth of the unstable layer will be sufficient for occasional
thundersnow through today and this evening.

..Hart/Dean.. 11/27/2025


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SPC Nov 27, 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
0638 PM CST Wed Nov 26 2025

Valid 270100Z - 271200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
The risk for thunderstorms appears negligible across much of the
nation tonight.

...01Z Update...

...Southern Florida/Keys...
Convection in a small cluster initially centered over interior
southern Florida, generally to the northwest of Greater Miami, has
undergone recent weakening. While occasional lightning persists in
stronger cores, guidance suggests that potential for this continuing
inland and near coastal areas will become increasingly negligible
through 02-03Z.

Otherwise, although more uncertain due to model spread, potential
for scattered convection capable of producing lightning might
increase late tonight near the lower Keys, if an increase in
large-scale ascent is able to overcome inhibition associated with
relatively warm layers aloft.

..Kerr.. 11/27/2025


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