Valid 221630Z – 231200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
INTO TONIGHT FROM EXTREME SOUTHEAST TX INTO CENTRAL MS…
Strong to briefly severe thunderstorms are possible from southeast
Texas to central Mississippi through tonight.
…Lower MS/TN Valley regions through early Saturday…
A lead shortwave trough over OK this morning will eject
east-northeastward and weaken in confluent flow regime aloft, while
an upstream speed max over the southern Rockies progresses eastward
to the Ark-La-Tex by 23/12z. At the surface, a cold front will move
slowly southeastward across the Ark-La-Miss and southeast TX today.
A weak surface cyclone is expected to develop along the front
tonight across the lower MS Valley and then move northeastward to
the TN Valley by Saturday morning. The warm sector south of the
front is characterized by boundary-layer dewpoints ranging from the
mid 60s in west central MS to the lower 70s along the upper TX
coast, with weak-moderate buoyancy (MLCAPE 500-1000 J/kg). The
relatively larger buoyancy will likely be confined to along and
south of a pre-frontal convective band from extreme southeast TX
into central LA today, where the highest dewpoints will reside and
some surface heating will occur in cloud breaks.
Since little in the way of cyclogenesis is expected today, low-level
shear is likely near peak this morning and should weaken some this
afternoon in the warm sector. This leaves an environment with
modest low-level shear and sufficient deep-layer shear/buoyancy for
some embedded supercells with a low-end damaging wind and/or tornado
threat. Convection will persist through tonight and spread into
northern AL, though lingering static stability near the ground
should limit any threat for strong/severe storms this far northeast.