MESO: Severe Thunderstorm
From
Weather Alert@454:1/105 to
All on Wed Jan 19 16:53:00 2022
ACUS11 KWNS 192100
SWOMCD
SPC MCD 192100
MSZ000-LAZ000-ARZ000-192300-
Mesoscale Discussion 0087
NWS Storm Prediction Center Norman OK
0300 PM CST Wed Jan 19 2022
Areas affected...Parts of northeastern Louisiana...southeastern
Arkansas...west central Mississippi
Concerning...Severe Thunderstorm Watch 16...17...
Valid 192100Z - 192300Z
The severe weather threat for Severe Thunderstorm Watch 16, 17
continues.
SUMMARY...The risk for potentially damaging wind gusts may gradually
increase with an evolving cluster or line of storms through 5-7 PM
CST.
DISCUSSION...Within the narrow corridor of deeper, boundary-layer
based moisture return, thunderstorms have begun to consolidate in an
area centered near the Louisiana/Arkansas border. This is where
mid-level temperatures are a bit cooler, and forcing for ascent
associated with a low-amplitude short wave trough emerging from the
southern Great Plains is stronger, compared to areas farther south,
near the Gulf coast. Further upscale growth seems probable during
the next few hours, as the low-level moist axis gradually shifts
eastward across the lower Mississippi Valley, coincident with the
progression of the mid-level impulse.
While latest model output suggests that flow around 850 mb will
continue to gradually weaken and veer in advance of a southward
progressing cold front, there may be some strengthening of
west-southwesterly flow to 30-40 kt as low as the 700 mb level.
With colder surface air just now gradually spreading through the
I-40 corridor of central Arkansas, it appears unlikely that
convection will be undercut by the cold front anytime soon. As a
result, there appears a window of opportunity for an upscale growing
cluster or line of storms to generate a cold pool, perhaps gradually
posing increasing potential to produce potentially damaging surface
gusts.
Near or just ahead of the developing convective system, while modest
to weak low-level flow will limit hodograph size, model forecast
soundings do exhibit substantive clockwise curvature. An isolated
tornado or two may not be entirely out of the question, particularly
with any sustained discrete storm development.
..Kerr.. 01/19/2022
ATTN...WFO...MEG...JAN...SHV...
LAT...LON 32599222 33269130 34139051 33498933 31599184 32119290
32599222
$$
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