Gulf Tropical Threat to Douse Flood-Weary Texas, Louisiana

A historic deluge of rain this week unleashed serious flooding across portions of Texas and Louisiana, leaving roads underwater and leading to high water rescues. Now, before the week is over, more unwanted news is in store for the region. A tropical system could develop in the western Gulf of Mexico by Friday afternoon, and move into the Texas coast Friday evening.

Some of the flood-stricken areas are among those still recovering from several tropical strikes during the record-shattering 2020 Atlantic hurricane season. 

AccuWeather forecasters warn that additional rounds of heavy rain from a possible tropical system will threaten some of the communities that have already been hardest hit by flooding this week. The impacts of this week's excessive onslaught of rainfall are likely to continue well into next week.

(All weather maps and graphics courtesy Accuweather)

Early Thursday morning, a band of heavy rain and storms inundated portions of eastern and central Louisiana, an area that, up until Wednesday night, had missed out on the most persistent rain. By Thursday night the rain and thunderstorms retreated back over the Gulf of Mexico and began to shift back west and show signs of rotation. The disturbance has a high chance of developing into an organized tropical system by later Friday, AccuWeather forecasters say.

“Conditions are conducive enough for tropical development in the western Gulf of Mexico,” AccuWeather Senior Meteorologist Rob Miller said. However, it will have to become better organized quickly, since it will track inland by the evening.

This disturbance is expected to move inland by late Friday night in between Corpus Christi, Texas, and Houston. This disturbance is churning at the same time as another system that has a high chance to become a named storm near Bermuda before the start of the weekend. The first two names on the list for the 2021 Atlantic Hurricane season are Ana and Bill. Whichever storm strengthens enough to become a named system first will be given the name Ana.

Miller warned that regardless of the extent of tropical development, heavy downpours and thunderstorms would once again target southeast Texas and western Louisiana into Friday night.

A swirl of clouds can be seen in the western Gulf of Mexico Friday morning as a tropical system tries to take shape. (RAMMB/CIRA)

Several additional inches of rain could fall Friday afternoon through Friday night in areas that have already picked up nearly 20 inches of rain near the coastline of southeast Texas and southwest Louisiana.

Even after the disturbance in the Gulf moves inland Friday night, downpours can persist into Saturday and are likely to focus on the areas that have already been doused over and over again this week, AccuWeather forecasters say.

"The threat for rounds of rain will continue across western Louisiana and eastern Texas through Saturday before drier conditions prevail," said AccuWeather Senior Meteorologist Tyler Roys.

This week, widespread rainfall amounts of 4 to 8 inches have already fallen along parts of the Gulf Coast, in cities like Baton Rouge, Louisiana, and Houston, to as far inland as Dallas, Oklahoma City, and Little Rock.

The intense rainfall led to flooding and forced high water rescues and closed roadways. At least five people were killed amid the flooding, according to the Louisiana Department of Health.

The cities of Beaumont, Texas, and Lake Charles, Louisiana, have been among the hardest hit, and both cities picked up more than 14 inches of rain since Sunday.

In fact, Lake Charles has already had the city's third wettest May on record after this week's rain. The unrelenting wet weather this week added to the string of extreme events that have affected the city in the past year.

Another 2-4 inches of rainfall, with locally higher amounts once again with the threat of an organized tropical system in the picture, is likey in this area Friday and Saturday, exacerbating the ongoing flooding disaster.

More flooding of roadways, especially those near waterways, is expected to continue. Forecasters and officials urge motorists to avoid driving through flooded roadways, and follow the guidance of "turn around, don't drown." The additional rain will also push up water levels of rivers and streams.

After Saturday, the weather forecast is likely to improve, but not all of the storm's impacts will dwindle.

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"As we end the weekend and go into early next week, showers and thunderstorms will fire up, especially in the afternoons, but will not be as constant as what occurred this week," Roys explained.

Roys also added that, given how saturated the ground is already, just a quick downpour could lead to flooding more easily.

The showers and thunderstorms are likely to help keep temperatures near or just below normal, unlike in the Southeast, where temperatures could hit 100 degrees for the first time this season.

Even after the torrential downpours come to an end by this weekend, problems will not be in the rearview mirror yet for some areas over the South Central states. The most long-lasting impact from the deluge is likely to be the resultant river flooding, which is forecast to persist in some areas through much of next week.

"As the water from the swollen, flooded rivers continues to filter downstream, rivers are likely to continue above flood stage into part of next week along the Gulf Coast," Roys added.

The Neches River at Saltwater Barrier, Texas, pushed above major flood stage (8 feet) on Wednesday and is forecast to crest near 11 feet over the weekend. The river is unlikely to drop below the 8-foot mark through the middle of next week.

The Calcasieu River outside of Lake Charles surpassed the major flood stage (6 feet) after Monday's record-breaking rainfall. The river is forecast to remain above the major flood stage through at least next Tuesday.