Multiple large tornadoes on the ground in Mississippi.

ACUS01 KWNS 151636
SWODY1
SPC AC 151634

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1134 AM CDT Sat Mar 15 2025

Valid 151630Z - 161200Z

...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
MISSISSIPPI AND ALABAMA...

...SUMMARY...
A tornado outbreak is expected today across the central Gulf Coast
States and Deep South into the Tennessee Valley. Numerous
significant tornadoes, some of which should be long-track and
potentially violent, are expected this afternoon and evening. The
most dangerous tornado threat will begin across eastern Louisiana
and Mississippi through this afternoon, spread across Alabama this
afternoon into the evening, and reach western parts of the Florida
Panhandle and Georgia tonight.

...Southeast into the Tennessee Valley...
No changes have been made to the High Risk area across the
Southeast. Multiple supercells are ongoing late this morning across
southeast LA into MS, along and east of a convectively reinforced
baroclinic zone. A very favorable parameter space exists across the
Southeast for severe thunderstorms, which will likely help maintain
ongoing supercells and small line segments. Current expectations are
for the most favorable strong to intense tornado environment to
continue across MS this afternoon and evening, with moderate
instability and ample low-level and deep-layer shear already in
place. The tornado threat will spread eastward into AL and southern
TN this afternoon and evening, and eventually into parts of the FL
Panhandle, western/central GA, and eastern TN overnight in tandem
with an ejecting southern-stream shortwave trough and related
intense low-level jet. Both large hail and severe/damaging winds
will also be a threat with these supercells. Upscale growth into one
or more bowing line segments will be possible, especially with
northward extent into the TN Valley and eastward into GA, where
potentially numerous to widespread severe/damaging winds may occur.
Reference Mesoscale Discussions 199, 200, and 201 for more
information on the near-term severe threat across the Southeast.

...Southern Appalachians...
As an upper trough pivots east into the region late tonight, strong
low-level warm/moist advection will contribute to a gradually
destabilizing airmass. Despite weaker buoyancy with eastward extent
over northeast GA into the western Carolinas, very intense low to
mid-level flow will aid in maintaining a risk for a few supercells
and line segments into a more limited thermodynamic environment.
This will potentially yield a risk for damaging gusts and an
isolated tornado threat through early Sunday morning.

...Ohio Valley into Southern Great Lakes...
Guidance maintains a belt of strong 850 mb flow through midday,
before an intensification of the northern periphery of a low-level
jet extending from the central Gulf Coast into the Mid South
overspreads the region. Uncertainty remains regarding the magnitude
of destabilization behind earlier convective activity, and its
resultant effects on severe potential. Most guidance generally shows
only weak buoyancy (at or below 500 J/kg of MUCAPE), but some
airmass recovery in the wake of earlier thunderstorms may occur over
IN into OH and vicinity.

..Gleason/Squitieri.. 03/15/2025

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