Day 1 Severe Weather Outlook

Valid 131200Z – 141200Z

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
MS VALLEY TO MIDDLE TENNESSEE…

…SUMMARY…
Some hail threat will be noted with thunderstorms that develop
across the lower Mississippi Valley into the Tennessee Valley Monday
night.

…Lower MS Valley/TN Valley…

A large-scale upper high is expected to remain anchored off the
southeastern US during the day1 period while the primary band of
westerlies extends from northern CA into the OH Valley. This flow
regime is expected to encourage a plume of higher-PW (1.5 “) air to
advect around the western periphery of the ridge across the lower MS
Valley into TN by the latter half of the period. While negligible
height changes are forecast across this region, it appears the ridge
may flatten some across the TN Valley as a possible weak disturbance
within the southern branch ejects across TX into the Mid-South
during the overnight hours. As moisture advects into this region,
forecast soundings suggest more than ample buoyancy will evolve such
that parcels lifted from near 850mb will yield MUCAPE in excess of
1500 J/kg. In addition, cloud-bearing shear will be quite strong,
more than adequate for sustained rotating updrafts. While it’s not
clear how many supercells will ultimately evolve within this
corridor, there is some concern that organized elevated convection
could materialize. Steep mid-level lapse rates support hail and 5%
severe probs will be added to account for this threat, primarily
during the latter half of the period.

..Darrow/Nauslar.. 01/13/2020

$$

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