Valid 021630Z – 031200Z
…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS MID-SOUTH
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.