SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0224 AM CST Sun Mar 02 2025
Valid 041200Z - 051200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS TUESDAY
AFTERNOON AND EVENING ACROSS SOUTHERN ARKANSAS....MUCH OF NORTHERN
AND CENTRAL LOUISIANA AND CENTRAL/SOUTHERN MISSISSIPPI...
...SUMMARY...
One or two organized lines or clusters of thunderstorm, and perhaps
a few supercells, will pose a risk for damaging wind gusts, a few
tornadoes and hail, primarily across parts of the lower Mississippi
Valley into Southeast, Tuesday through Tuesday night.
...Discussion...
Latest model output remains a bit varied concerning the evolution
and motion of a significant mid/upper trough, which is generally
forecast to be in the process of shifting across and east of the
southern Rockies Monday night into early Tuesday. However, guidance
indicates that it will remain progressive, and likely to overspread
much of the Mississippi Valley by the end of the period. In
lower-levels a broad deep cyclone is likely to continue to evolve,
with the center forecast to track from Kansas into the Upper Midwest
by 12Z Wednesday.
In the wake of a recent intrusion of dry/potentially cool air,
associated with surface ridging shifting east of the Atlantic
Seaboard, models indicate that an influx of moisture off the western
Gulf Basin will advect eastward ahead of the cold front trailing the
cyclone. However, northeast of the southeastern Great Plains into
lower Mississippi Valley, the moisture return may remain elevated
above a residual cool/stable near surface layer. Still, large-scale
forcing for ascent and destabilization will probably be sufficient
to support extensive thunderstorm development across the interior
U.S., and a fairly broad area with at least a conditional risk for
severe storms, given the strength of flow/shear in the evolving warm
sector.
...Lower Mississippi Valley into Southeast...
An initially well-defined near-surface baroclinic zone may extend
from the Arkansas/Oklahoma vicinity southeastward through the lower
Mississippi Valley at the outset of the period. While it appears
that this boundary may become more diffuse while shifting eastward
during the day, it may still provide the primary focus for an
organizing cluster and/or discrete supercell development, as forcing
for ascent associated with a short wave perturbation within the
larger-scale mid/upper troughing overspreads the region.
Of concern, models indicate that this feature will be accompanied by
an intense jet core, which may include south-southwesterly winds of
70-100 kt in the 850-500 mb layer overspreading portions of
Louisiana and Mississippi. These speeds appear generally forecast
within the inflow layer of potential storm development, with speeds
tending to weaken to 40-50 kt as they veer to a more westerly
component in the potential downdraft source region. So uncertainty
exists concerning the magnitude of potential downward mixing of
momentum in convective development.
Even so, particularly along the remnant boundary, the environment
probably will become conducive to potential for damaging wind gusts,
a few tornadoes and some hail across southern Arkansas and northern/
central Louisiana into Mississippi. As this activity spreads
eastward Tuesday night, the extent to which near-surface
thermodynamic profiles support a risk for damaging surface gusts and
tornadoes across Alabama into Georgia remains unclear, but it seems
likely to diminish with eastward extent and time.
..Kerr.. 03/02/2025
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