Mesoscale Discussion 2078
NWS Storm Prediction Center Norman OK
0118 PM CDT Mon Sep 04 2023
Areas affected…Portions of the Lower/Middle MS Valley
Concerning…Severe potential…Watch unlikely
Valid 041818Z – 042045Z
Probability of Watch Issuance…20 percent
SUMMARY…Sporadic strong to severe downbursts and marginally severe
hail are possible over portions of the Lower/Middle MS Valley
through the afternoon. A watch is not currently expected.
DISCUSSION…Latest water vapor imagery indicates a weakening
midlevel wave lifting northeastward over the ArkLaTex region.
Preceding this wave, regional VWP data shows a belt 30-kt
south-southwesterly midlevel flow overspreading the Lower/Middle MS
Valley. Beneath the belt of enhanced midlevel flow and weak DCVA,
weakly confluent low-level flow and diurnal heating of rich
boundary-layer moisture (lower/middle 70s surface dewpoints), are
supporting isolated to widely scattered thunderstorm development
over western/central AR into LA. This activity should continue
spreading/developing northward and eastward as the midlevel wave and
related DCVA continue overspreading the area.
Relatively steep deep-layer lapse rates (sampled by a recent Little
Rock ACARS sounding) and around 20-30 kt of effective shear should
support loosely organized multicell clusters and perhaps transient
rotating updrafts. Strong to severe downbursts and marginally severe
hail could accompany the stronger storms that develop through the
afternoon, though the threat is expected to remain too
isolated/sporadic for a watch.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 34969349 34489358 33489377 33019377 32639352 32329318
32029270 31959230 32019182 32399138 33479087 34949067
37249068 37609094 37799135 37869201 37749285 37419334
37069359 36599360 36089352 35599346 34969349