SPC Jan 18, 2025 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1116 PM CST Fri Jan 17 2025

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY INTO
TONIGHT ACROSS THE FLORIDA PANHANDLE VICINITY INTO PORTIONS OF
NORTHERN FLORIDA AND THE WEST CENTRAL FLORIDA COASTAL
AREAS...ADJACENT PORTIONS OF SOUTHEASTERN ALABAMA AND SOUTHWESTERN
GEORGIA...

...SUMMARY...
Strong thunderstorms may impact parts of the eastern Gulf Coast
vicinity today through tonight, and pose some risk for locally
damaging wind gusts and perhaps a tornado or two.

...Synopsis...
Amplification of the mid/upper flow continues across the eastern
Pacific into North America.  Today through tonight, this is likely
to include a consolidating, positively tilted large-scale trough
encompassing much of North America.  Beneath an associated confluent
regime across the Rockies into the Appalachians, cold surface
ridging is forecast to build southeastward to the lee of the
Rockies.  An evolving frontal zone on the leading edge of the colder
air appears likely to be in the process of advancing off of the
northern and middle Atlantic Seaboard, and through the northwestern
Gulf of Mexico, by late this evening into the overnight hours. 
While stronger surface cyclogenesis becomes focused southeast
through east of Hudson Bay, a weak wave may develop and migrate
along the front across the eastern Gulf Coast through south Atlantic
Coast vicinity by late tonight.  In the wake of recent prior cold
intrusions, the boundary-layer over the Gulf of Mexico is still in
the process of recovering.  However, models suggest that moistening
within the pre-frontal southwesterly to west-southwesterly return
flow might become sufficient for weak boundary-layer destabilization
inland across the northeastern Gulf coast.

...Eastern Gulf States...
A strong belt of initially westerly mid/upper flow (associated with
remnant perturbations emerging from the southern mid-latitude and
subtropical eastern Pacific) is in the process of overspreading the
northern Mexican Plateau and Gulf Coast states.  Including speeds of
70-90 kt as low as the 500 mb level, deep-layer shear within the
warm sector of the evolving weak surface wave will be strong and
supportive of a conditional risk for organized severe thunderstorm
development.  Given the weak nature of the frontal wave, the lack of
stronger forcing for ascent and likelihood of generally modest
low-level hodographs still seem likely to limit the overall severe
weather potential.  However, with weak boundary-layer
destabilization forecast across the northeastern Gulf of Mexico into
at least the vicinity of coastal areas (from the western Florida
Panhandle area by midday into areas near/north of Tampa by 12Z
Sunday), the risk for severe thunderstorms may not be completely
negligible.

Isolated supercell development appears possible within the
pre-frontal warm advection regime, initiating within the more
buoyant offshore environment, before approaching coastal areas with
a risk for producing a tornado or severe wind gust.  This activity
could spread or develop inland.  However, the potential areal extent
of any weak boundary-layer destabilization inland of coastal areas,
across portions of Alabama/Georgia/northern Florida is more
uncertain.  Based on a consensus of model output, this seems most
probable in a small corridor across the western Florida Panhandle
and perhaps adjacent portions of southeastern Alabama/southwestern
Georgia and northern Florida this afternoon.

Upscale convective growth into tonight may be aided by forcing
associated with low-amplitude perturbations/coupled speed maxima
within the strong mid/upper flow.  By late tonight, this may include
the evolution of an extensive pre-frontal line extending offshore of
the Carolina coast through northern Florida into the northeastern
Gulf, approaching the Tampa vicinity.

..Kerr/Halbert.. 01/18/2025

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