Mesoscale Discussion 2263
NWS Storm Prediction Center Norman OK
0436 PM CST Thu Dec 18 2025
Areas affected...eastern MS...western/northern AL...southern Middle
TN
Concerning...Severe potential...Watch possible
Valid 182236Z - 190000Z
Probability of Watch Issuance...60 percent
SUMMARY...Increasing potential for a tornadic supercell or two
appears to be underway across eastern Mississippi. This should
spread into parts of western to northern Alabama through
mid-evening. A tornado watch is being considered.
DISCUSSION...A broken swath of semi-discrete convection has
increased from northeast to central MS along a pre-frontal
confluence axis. Surface temperatures have reached the low 60s north
to upper 60s south ahead of this axis, with 70s farther south and
behind this convection. This has yielded a plume of modest MLCAPE
from 500-1000 J/kg that should shift across western AL this evening.
Low-level to deep-layer shear is conducive to a few supercells
developing and being maintained within this regime. A tornadic
supercell or two is possible before convection probably weakens
later in the evening as instability wanes deeper into AL.