Mesoscale Discussion 1865
NWS Storm Prediction Center Norman OK
0252 PM CDT Wed Oct 12 2022
Areas affected...Southern AR....Northern MS
Concerning...Severe potential...Watch possible
Valid 121952Z - 122145Z
Probability of Watch Issuance...60 percent
SUMMARY...Thunderstorm coverage is expected to increase across
southern AR and northern MS over the next few hours. Some strong to
severe storms are possible, with damaging gusts and hail as the main
severe threats. A tornado or two is also possible.
DISCUSSION...Visible satellite imagery across southern AR and
northern MS continues to show an expanding and deepening cumulus
field, with several instances of convective initiation across
southern AR. This expansion/deepening is occurring amid strong
diurnal heating and resulting air mass destabilization. Recent
mesoanalysis estimates that little to no convective inhibition
remains and MLCAPE is around 1500 to 2000 J/kg.
Expectation is for gradually increasing thunderstorm coverage as
low-level convergence ahead of the approaching cold front persists.
Given its proximity to the front, thunderstorm development currently
appears most likely across southern AR. However, southern AR lies
within a corridor of slightly weaker mid-level flow, resulting in
less deep-layer shear here than areas farther east across northern
MS. Even so, isolated supercells capable of damaging gusts and/or
hail are possible.
Farther east, stronger mid-level flow results in greater deep-layer
shear. Additionally, a westward-moving outflow boundary is advancing
across northeast MS, with southeasterly surface winds in its wake.
This results in stronger low-level shear and a greater potential for
supercells capable of all severe hazards, including a tornado or
two, if storms can initiate and persist.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 34119376 34779317 34849046 34838906 33448916 33199321