- Day Three
acus02 kwns 241722
Storm Prediction Center ac 241721
Day 2 convective outlook
National Weather Service Storm Prediction Center Norman OK
1121 am CST Sat Feb 24 2018
Valid 251200z - 261200z
..there is a marginal risk of severe thunderstorms from the Texas
coast to the southern Appalachians...
Thunderstorms associated with a few strong wind gusts will be
possible on Sunday across portions of the southeast. A few other
strong to briefly severe thunderstorms may produce marginally severe
hail near the Texas/Louisiana coasts Sunday afternoon through the
An expansive cyclonic mid-level regime will expand over much of the
contiguous US Sunday, owing to the translation of multiple compact
shortwave troughs around its periphery. One of these will continue
lifting northeast from the Great Lakes into southern Canada,
progressively acquiring more of a negative tilt. To its southwest,
another impulse will advance from The Four Corners region eastward
to the Southern Plains, although it will gradually shear as it does
so. Lastly, a strong northerly jet maximum and associated vorticity
Max will drop south across the Pacific northwest.
The surface response will feature a ridge building eastward over the
mid-south, with a cold front pushing towards the East Coast and
gradually stalling near portions of the Gulf Coast.
..central Gulf Coast to the southern Appalachians...
A broken/decaying band of convection will likely stretch from parts
of the central Gulf Coast northeastward to the Appalachians Sunday
morning. Although low/mid-level lapse rates will be poor, surface
dew points in the low/mid 60s just ahead of the line may Foster
around 100-300 j/kg of MLCAPE. Stronger southwesterly low-level flow
will be departing to the northeast, but remaining 850mb winds around
30-50 kt and any persistent linear organization may yield a
localized gusty/ damaging wind threat, primarily Sunday morning.
Atop a near-surface stable layer behind the composite front/outflow
boundary, an uptick in warm-air advection will promote blossoming
convection across southeast Texas and western Louisiana late Sunday
into the overnight hours, with the activity slowly evolving eastward
thereafter. 700-500mb lapse rates around 6.5-7 c/km and ample
effective shear may promote a couple vigorous updrafts with
mid-level rotation, and any such cell may produce a few instances of