WPC concerned about flooding Wednesday afternoon for South Mississippi, Louisiana

Looking at the current radar, a batch of proficient rain producing storms is lifting across parts of Louisiana and Mississippi this afternoon. Rainfall rates are likely to eclipse one-inch-per-hour at times in some of the strongest storms and heavy batches of rain. If you’re keeping score at home, this is due to the remnants of Invest 91L.

The rain – and potential for flooding – has caught the attention of the Weather Prediction Center.

Per the WPC:

Summary…Scattered to numerous thunderstorms within a very moist environment will produce downpours capable of producing hourly totals greater than 2 inches. With several rounds of storms, some localized flash flooding is possible through the afternoon.

Discussion…GOES-East IR imagery this afternoon shows convective clusters around the Louisiana to Alabama Gulf Coasts deepening with the cooling cloud tops. Regional radar from the area several pulse to loosely organized clusters of storms fairly numerous already this afternoon.This activity is working within a very moist environment with the latest GPS TPW product showing values of 2 to 2.3 inches. Instability, despite cloud cover, is still fairly sufficient for destabilization with MLCAPE of 1500-2000 J/kg. Finally, soundings from southern LA show very warm cloud depths of 4-5 km, and also weak flow through the column which should keep storm motions slow.

Through this afternoon, this convection should persist with the potential for hourly totals reaching or exceeding 2 inches in the stronger storms. Through 00z, there’s potential for 2-4 inch amounts with some higher totals around 5 inches possible,
generally across southern/southeast LA into southern/south-central MS and southern AL.

The main limiting factor against flash flooding will be the relatively higher flash flood guidance and also the drier than normal conditions experienced in the last 14 days. Nonetheless, if storms train or move over sensitive/urban locations, some flash flooding is possible.