Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1022 AM CST Wed Dec 17 2025

Valid 171630Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN IDAHO AND NORTHERN UTAH...

...SUMMARY...
While strong to locally severe winds may occur with low-topped
convection through early afternoon across parts of southern Idaho
and northern Utah, the overall threat for organized severe
thunderstorms appears low.

...Interior Northwest and Northern Great Basin/Rockies...
A powerful mid-level shortwave trough and associated sub-980 mb
surface low will move quickly eastward today across the interior
Northwest/northern Rockies and adjacent western Canada. A strong
surface cold front will likewise translate east-southeastward over
the northern Intermountain/Great Basin region late this morning into
the afternoon. Widespread cloud cover remains prevalent ahead of the
front across southern ID into northern UT and vicinity, with cool
surface temperatures and very limited low-level moisture also
present. MUCAPE is expected to remain only barely sufficient to
support convection. But, given the enhanced flow at low levels noted
on recent VWPs from KCBX/KSFX, it is not entirely out of the
question that convectively augmented gusts may exceed the already
strong background gradient winds on a localized basis. The Marginal
Risk has therefore been maintained for parts of southern ID/northern
UT and vicinity, even though the overall threat for organized severe
thunderstorms will remain low.

..Gleason/Weinman.. 12/17/2025

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0147 PM CST Wed Dec 17 2025

Valid 172000Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms will continue across portions of the Intermountain
West and Texas/Louisiana coasts through this evening. The overall
threat for organized severe thunderstorms appears low.

...20z Update...
The Marginal Risk across southern Idaho/northern Utah has been
removed with this outlook. Thunderstorm activity has shown gradual
weakening with only meager MLCAPE remaining. Occasional strong
gradient winds will continue with the upper-level wave but the
overall convective severe threat appears to be waning.

..Thornton.. 12/17/2025

.PREV DISCUSSION... /ISSUED 1022 AM CST Wed Dec 17 2025/

...Interior Northwest and Northern Great Basin/Rockies...
A powerful mid-level shortwave trough and associated sub-980 mb
surface low will move quickly eastward today across the interior
Northwest/northern Rockies and adjacent western Canada. A strong
surface cold front will likewise translate east-southeastward over
the northern Intermountain/Great Basin region late this morning into
the afternoon. Widespread cloud cover remains prevalent ahead of the
front across southern ID into northern UT and vicinity, with cool
surface temperatures and very limited low-level moisture also
present. MUCAPE is expected to remain only barely sufficient to
support convection. But, given the enhanced flow at low levels noted
on recent VWPs from KCBX/KSFX, it is not entirely out of the
question that convectively augmented gusts may exceed the already
strong background gradient winds on a localized basis. The Marginal
Risk has therefore been maintained for parts of southern ID/northern
UT and vicinity, even though the overall threat for organized severe
thunderstorms will remain low.

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1125 AM CST Wed Dec 17 2025

Valid 181200Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe potential will be limited on Thursday, but isolated strong
wind gusts are possible across portions of the Lower Ohio and
Tennessee Valleys.

...Synopsis...
A strong upper trough will move across Midwest on Thursday with low
pressure moving across the Great Lakes. A cold front will extend
south from this low with wind shift moving across the OH and TN
Valleys during the day and into the evening. Minimal destabilization
is forecast ahead of the front as clouds and early day precipitation
hamper heating. Mostly elevated instability is forecast, though
shear profiles will be strong. Despite a marginal/cool boundary
layer across the warm sector, deeper ascent along the cold front
could support shallow moist convection capable of augmenting gusts
with the frontal passage.

Elsewhere, moisture and instability will increase overnight well off
the NC Coast, but supercells developing over the water may
eventually skirt the Outer Banks of NC toward the end of the period.
At this time it appears the instability gradient will remain
offshore.

..Jewell.. 12/17/2025