Day 1 Severe Weather Outlook

Valid 022000Z – 031200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
MISSISSIPPI DELTA AND CENTRAL GULF COAST STATES…

…SUMMARY…
Strong to severe thunderstorms may impact parts of the Mississippi
Delta and central Gulf Coast States, offering damaging wind gusts
and a tornado threat.

…20Z Update…
A more coherent band of thunderstorms has recently developed across
central/south-central LA amidst the modest convergence with the
broad frontal zone. Recent surface analysis shows dewpoints in the
upper 60s/low 70s within the downstream air mass across much of
southeast LA and southern MS. However, given the strong
front-parallel flow aloft, resulting north-northeastward storm
motion may result in storms lagging behind their own outflow. This
would keep storms predominately elevated despite the increasing
downstream instability. A more easterly storm motion would likely
support a higher severe risk.

Even so, potential still exists for occasional/sporadic storm
organization and the risk for damaging wind gusts with any bowing
line segments. Additionally, given the strong 1-2 kft winds sampled
by recent area VADs, a low tornado potential also continues,
particularly with any deep convection that can persist ahead of the
primary line.

..Mosier.. 01/02/2020

.PREV DISCUSSION… /ISSUED 1022 AM CST Thu Jan 02 2020/

…LA/MS/AL…
A strong upper trough is tracking across TX and northern Mexico this
morning, with 75-100 knot southwesterly midlevel winds extending
from the western Gulf of Mexico into parts of LA/MS/AL. At the
surface, a frontal boundary extends from southwest LA into central
MS. South of the boundary, dewpoints in the mid-upper 60s are
streaming northward and resulting a marginally unstable air mass
(MLCAPE around 500 J/kg). All 12z model guidance agrees that
scattered thunderstorms will form along the front this afternoon
over LA/MS and track eastward as the air mass destabilizes northward
across AL. The best environment for surface-based storms, including
possible supercells and bowing structures, will be in the SLGT risk
area of central LA into central MS and west-central AL. Forecast
soundings in this area show substantial low-level shear conducive to
a few tornadoes, but convection will likely be linear in nature,
suggesting QLCS wind damage and tornadoes are the main threats. The
storms should generally weaken as they track across central/northern
AL, but may remain occasionally strong/severe through much of the
evening.

$$

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