Day 1 Severe Weather Outlook

Valid 021630Z – 031200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MID-SOUTH
REGION…

…SUMMARY…
Scattered severe thunderstorms with large hail, a couple tornadoes,
and damaging winds are anticipated across the Mid-South, after about
5 PM CST through tonight.

…Mid-South to northeast TX…
Primary change is to expand Marginal and Slight Risks northward and
eastward with above-average confidence in scattered severe
thunderstorm coverage being realized.

At the surface, a weak cyclone will move northeast along a
baroclinic zone from east-central OK across the OH Valley tonight.
Low-level moistening continues to the south of the front, and 60-63
F surface dew points will spread northeast across most of the
Mid-South by evening. This moistening will occur beneath the eastern
extent of a plume of steep mid-level lapse rates overspreading from
KS/MO/OK. The base of the elevated mixed layer will be warm enough
to cap the boundary layer until about early evening.

Sustained thunderstorm development is expected near the front where
low-level convergence will be relatively stronger, just ahead of the
surface low across the northeast AR/southeast MO vicinity. MLCAPE
of 1000-1500 J/kg, effective bulk shear around 40 kt, mid-level
lapse rates in excess of 8 C/km, and elongated/straight-line mid to
upper-level hodographs will favor multiple splitting supercells
capable of producing large hail, some of which may be significant. A
modest increase in low-level shear this evening could support a
tornadic storm or two as well. Storm-scale consolidation and the
impinging of 50-kt westerlies at 700 mb may yield upscale growth
into a modest-sized MCS across parts of TN and southern KY with the
damaging wind threat peaking between 03-07Z.

Farther southwest, isolated thunderstorm development is also
possible this evening along the front into northeast TX. However, a
shallow moist boundary layer and widespread high clouds cast some
doubt on diurnal storm formation. Assuming storms form this
evening, isolated large hail and strong wind gusts will be possible.

..Grams/Leitman.. 03/02/2020

$$

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