Day 1 Severe Weather Outlook

Valid 301630Z – 011200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
ARKLATEX TO LOWER MS VALLEY AND MID-SOUTH…

…SUMMARY…
Scattered severe thunderstorms are expected through this evening
across the Arklatex, Lower Mississippi Valley, and Mid-South
regions. A couple tornadoes, large hail, and damaging winds are
anticipated.

…Arklatex to Lower Mississippi Valley and Mid-South…
At late morning, a northeast/southwest-oriented broken band of
occasionally strong/locally severe convection continues to progress
east-southeastward across west-central Arkansas/northeast Texas. A
band/wave-like feature precedes this convection by about 70-80
miles, and this could also be a factor for renewed thunderstorm
development/intensification this afternoon across the ArkLaMiss
region. For short-term expectations, reference Mesoscale Discussion
2177.

Aided by a 50 kt southwesterly low-level jet ahead of the front, a
corridor of upper 60s F surface dew points across east Texas will
continue to advect east-northeastward across Louisiana and far
southern Arkansas this afternoon, with a bit more modest
moistening/destabilization expected this evening eastward into
Mississippi/western Tennessee. An instability-limiting aspect will
be that cloud cover/stratus may tend to persist within the warm
sector, which will likely result in sub-optimal parcel accelerations
and probably curb the overall magnitude of today’s severe risk.

Regardless, a diurnal destabilization trend will occur and
deep-layer shear will strengthen as a powerful mid-level jet (100
kt) amplifies over the southern Plains and Ozarks. These factors
will aid in increasing convective intensity/organization this
afternoon, particularly across far northeast Texas, northern
Louisiana and southern/eastern Arkansas and eventually into
Mississippi. Deep-layer/low-level shear will be more than adequate
for both supercells and well-organized bands capable of damaging
winds and a couple of tornadoes. While mid-level lapse rates are not
steep, favorable hodographs and somewhat modest forcing/sufficiently
favorable convective mode will support the possibility of large
hail.

Overall severe threat should wane with eastern extent across the
Tennessee Valley tonight given a diminishing trend of surface-based
instability.

..Guyer/Cook.. 11/30/2019

$$

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