A shortwave trough is going to track quickly across the lower Mississippi Valley and Tennessee Valley tomorrow into tomorrow night.
Multiple rounds of widespread showers and thunderstorms will be likely from east Texas, Louisiana, and Mississippi during the day. Activity will then spread into Alabama and the Florida Panhandle tomorrow afternoon and overnight.
Heavy Rain
Periods of heavy rain will be likely, with a general 1 – 3″ of rainfall accumulation forecast by the Weather Prediction Center (see figure 2). Some localized flooding issues could arise.
However, south Louisiana, south Alabama, and the Florida Panhandle are abnormally dry per the latest drought monitor. So rain will be beneficial for these locations.
Severe Threat
In addition to heavy rain, there will be a severe weather threat to contend with.
It doesn’t look like high CAPE (instability) values will make it too far inland on account of storms during the morning. However, elevated lapse rates and bulk shear values are expected.
The Storm Prediction Center has defined a level 2 (slight) risk area, with a level 1 (marginal) risk area surrounding it (see figure 1).
Convective mode will be messy. Clusters of storms and quasi-linear segments with embedded supercells are being predicted by model guidance (see figure 3).
Large hail and damaging winds are going to be the primary threats. But a couple of tornadoes can’t be ruled out.
