Heavy rain, flash floods risk for South through late this week

Flash flooding is possible from eastern Texas and eastern Oklahoma into the lower Mississippi Valley through Thursday. The weather is being controlled by a “sluggish” low-pressure system moving through the area.
A “high risk” of flash flooding has been issued by NOAA’s Weather Prediction Center (WPC) for Wednesday and Wednesday night along the upper Texas coast and in southwest Louisiana, including Houston and Lake Charles, Louisiana. Rainfall rates of 1 to 4 inches per hour are possible in showers and storms that spread through this region, likely triggering flash flooding.
Today, through tomorrow, another five inches of rain is expected in east Texas and central Louisiana, while four to ten inches of rain is expected along and south of the I-10 corridor of southeast Texas, southwest, and south-central Louisiana.

Rain forecast through Sunday

NOAA WPC

This is due to a stream of warm moisture moving up from the Gulf. This will continue to move Eastward over the Lower Mississippi Valley where rainfall of 1-3 inches can occur with daily rainfall averaging 3-5 inches. Local residents are warned to be on the lookout for road closures, substantial delays and the need to alter their routes.

There will be substantial flooding in low-lying areas and areas of poor draining. Do not attempt to drive through a flooded street. Locations like Houston and Beaumont, Texas, and New Orleans, Lake Charles and Baton Rouge, Louisiana, will be at risk for inundation in some neighborhoods.

Aerial photograph of the first bay opening on the Morganza Floodway on 14 May 2011. The Mississippi River is in the upper left background, and the Atchafalaya Floodway to the right.

US Army Corps of Engineers

Adding to the threats, heavy rainfall over the Central states and melting snow from the Rockies has created a surge of water from the Missouri and Arkansas rivers that is emptying into the Mississippi River and flowing southward. The river surge in the lower Mississippi Valley is expected to occur at about the same time the heavy rains hit.

There are plans by the Army Corps of Engineers to open the Morganza Spillway in Morganza, La. on June 12, 2019. This will be the third time ever the spillway has been opened and only the second time due to flooding.

The release of water at the spillway and the Old River structure diverts some water from the main stem of the Mississippi River and creates flooding in the Atchafalaya River Basin. NOAA’s Weather Prediction Centers says that localized rainfall totals of 6 to 10 inches are possible in the high-risk flood area.