Louisiana and southern Mississippi are also dealing with the threat for flash flooding this evening.
From the WPC:
Summary…A squall line is moving into an area recently saturated by rainfall last night. Despite its forward progression, flash flooding should be possible.
Discussion…A squall line is moving southeast at 30+ kt through central la at this time, with 15 kt progression seen farther southwest across southeast tx. Mucapes of 3000-5000 j/kg lurk offshore, which should foster continuing forward progression. Like last night, convergence is seen at 850 hpa across eastern la and ms with low-level inflow of 30 kts per vad wind profiles, just above the magnitude of the mean 850-400 hpa wind. Precipitable water values of 1.75-2″ inhabit the region.
A few of factors favor a flash flood threat in this region. Soils were saturated by moderate to heavy rainfall last night. Forward propagating corfidi vectors weaken overnight, suggesting that the convective line could slow down ~10 kts from its current motion across la and ms, which could re-enhance rainfall rates. A few cells along the outflow boundary ahead of the system in southern la and southern ms have remained stationary. With a slight uptick of 850 hpa inflow expected across southeast la and ms, more convection could form near or elevated over the outflow boundary before the squall line comes through. The available moisture supports rainfall rates up to 2″ an hour. The flash flood threat should slowly erode from southwest to northeast across this area, as 850 hpa inflow weakens across tx and/or the squall line progresses into the gulf of mexico. None of mesoscale guidance is carrying this line quick enough eastward per recent radar trends. Flash flooding is a concern over saturated soils, with hourly rain rates of up to 2.5″ expected across tx and up to 2″ elsewhere across eastern la and portions of ms.
