Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1134 PM CST Thu Mar 07 2024
Valid 081200Z - 091200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY INTO TONIGHT
ACROSS PARTS OF NORTHEASTERN TEXAS...SOUTHERN ARKANSAS...MUCH OF
LOUISIANA...CENTRAL AND SOUTHERN MISSISSIPPI AND ALABAMA AND AN
ADJACENT PORTION OF THE FLORIDA PANHANDLE...
...SUMMARY...
Strong to severe thunderstorms may impact a corridor from parts of
the southeastern Great Plains through the Gulf Coast states today
through tonight. Some may be accompanied by potential for
tornadoes, in addition to severe hail and wind, particularly across
parts of southern into central Mississippi and Alabama late this
afternoon into tonight.
...Synopsis...
An amplified regime within a belt of westerlies emanating from the
mid-latitude Pacific may continue to develop eastward through this
period. This may include at least a short-lived evolution of a high
center across the northern U.S. Intermountain region, within broader
scale mid/upper ridging spreading inland of the Pacific coast
through the eastern Canadian Prairies and portions of the northern
U.S. Great Plains. Downstream of this ridging, significant
troughing is forecast to dig across the Upper Midwest/upper
Mississippi Valley vicinity, perhaps gradually beginning to come in
phase with a lead impulse, within broad mid/upper troughing slowly
emerging from the Southwest, before the end of the period.
Substantive spread is evident within/among the various model output
concerning this evolution, and model depictions of associated
surface frontal wave development/cyclogenesis across and east of
the Mississippi Valley are rather varied. A significant low-level
cold intrusion to the lee of the Rockies is forecast to surge
through the remainder of the southern Great Plains and northwest
Gulf Coast vicinity today through tonight, while advancing a bit
slower across/east of the middle Mississippi Valley and into the
lower Mississippi Valley. It does appear that a more modest ongoing
cold intrusion to the lee of the Appalachians will stall, with a
frontal zone becoming better defined across the southern Piedmont by
12Z Saturday.
A more substantive return of low-level moisture is ongoing across
the northwestern Gulf of Mexico and northwestern Gulf coastal plain
vicinity. This is likely to continue to advect northeastward, and
may include surface dew points increasing to near 70F across and
east of the lower Mississippi Valley. How far north and east will
hinge on at least a couple of factors, including the impacts of
outflow from persistent convective development forecast to spread
east of the lower Mississippi Valley vicinity, and the extent of the
development of a possible trailing surface low. Both of these
remain uncertain, and could considerably impact the extent of the
severe weather potential for this period.
...Gulf States...
Convection rooted in ascent associated with lower/mid-tropospheric
warm advection, near the northwestern periphery of low-amplitude
subtropical ridging, may be ongoing at 12Z this morning across the
lower Mississippi Valley, and persist through much of the period,
gradually spreading eastward across the remainder of the Gulf into
southern Atlantic Coast states. Substantive low-level moistening
appears likely to follow in its wake, with trailing convective
outflow at least initially limiting the northern extent of the
better boundary-layer moistening.
By mid to late afternoon, a zone of stronger differential surface
heating may become best defined across parts of southwestern Alabama
and south central Mississippi into northeastern Louisiana, near a
developing surface low. Coupled with the boundary-layer moistening,
weak to moderate CAPE (500-1000+ J/kg) may develop along this zone
and contribute to the initiation of new thunderstorm development, in
the presence of continuing low-level warm advection, beneath broadly
difluent mid/upper flow. Beneath seasonably strong
west-southwesterly mid/upper flow, the environment may become
conducive to the evolution of sustained discrete supercells.
Moderate southerly low-level flow across this region may also
promote sizable clockwise curved low-level hodographs, with
conditional potential for a strong tornado or two, depending on the
evolution of the near surface thermodynamic profiles.
It is possible that this activity could persist into the evening,
and perhaps overnight, with a tendency for the lingering focusing
surface boundary to develop east-northeastward across parts of
southern into central Alabama and Georgia. Again much will depend
on the upstream surface low evolution, which remains unclear.
..Kerr/Thornton.. 03/08/2024
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