re: Severe Weather Thread, TX LA MS AL GA FL (Slight) 3/3-3/4

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Mesoscale Discussion 0157
NWS Storm Prediction Center Norman OK
0157 PM CST Wed Mar 04 2020

Areas affected...Portions of southern Louisiana into far southern
Mississippi

Concerning...Severe potential...Watch possible

Valid 041957Z - 042200Z

Probability of Watch Issuance...40 percent

SUMMARY...Isolated storm development is possible over the next few
hours south of a near-stationary front. Damaging gusts and perhaps a
tornado or two are possible. Convective trends will continue to be
monitored for a possible watch issuance.

DISCUSSION...Discrete cellular development has recently been noted
across southern LA within a low-level confluence zone. These storms
are evolving south of the surface quasi-stationary baroclinic zone,
where a strongly sheared, surface-based airmass is in place (1000+
J/kg MLCAPE coinciding with 200+ m2/s2 effective SRH), owing to the
presence of a diurnal, dynamically driven low-level jet. In
addition, recent visible satellite data suggests that modest
insolation is taking place, helping to locally boost instability
across southern LA into far southern MS.

Given the stronger upper-level support lagging to the west, it is
unclear how much more widespread/intense convection will become.
However, any storms that manage to obtain and sustain supercellular
structures will pose the threat for damaging wind gusts and perhaps
a tornado or two, especially for any storms that can latch to the
aforementioned surface boundary. As such, convective trends will
continue to be monitored for the potential need of a WW issuance.

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