Potential Tropical Storm Could Bring a Major Flood Threat to the South

The National Hurricane Center is keeping a close eye on a disturbance over South Texas that could soon become the first tropical storm of the Atlantic hurricane season. Federal forecasters expect multiple days of heavy to “prolific” downpours to drench much of the South, bringing a “considerable flood threat” to the region.

As of 8 a.m. ET on Tuesday, the system was producing a large area of disorganized showers and thunderstorms centered over South Texas, according to the NHC. Forecasts show it tracking northeastward along the Texas coast and potentially emerging over the northwestern Gulf of Mexico by the afternoon or evening. There’s a 60% chance that this disturbance will organize into a tropical cyclone within the next 48 hours, but its development will depend on how long it lingers over warm Gulf waters, meteorologist Ben Noll reports for the Washington Post.

If the system does develop into a named storm, it will be called Arthur. But “[r]egardless of tropical cyclone formation, interests across southern and eastern Texas, southern portions of Louisiana and Mississippi should prepare for periods of intense rainfall over the next several days, which could produce widespread, life-threatening flash, urban, and river flooding,” the NHC stated in an update early Tuesday morning.

Atmospheric moisture levels will be *prolific* across the South this week, with the potential for flooding rain spreading across a corridor from Texas to the Carolinas.

In some areas, record-breaking precipitable water of 4 inches is forecast, signaling a waterlogged atmosphere. pic.twitter.com/tKuFyV8SLy

The National Weather Service has issued flood watches stretching from South Texas across the southeastern portion of the state, most of Louisiana, and into south-central Mississippi. Over the next three days, the agency expects to see storm total rainfall amounts of five to seven inches (12.7 to 17.8 centimeters) and locally higher amounts along the Texas coastline into Louisiana.

By Friday, localized areas within the storm’s path could receive over a foot (30.5 centimeters) of rain, Noll reports. Cities bracing for its arrival include Houston, Texas; Lafayette, Louisiana; Jackson, Mississippi; Montgomery, Alabama; and Atlanta, Georgia.

This slow-moving storm is carrying copious amounts of tropical moisture, which explains why it is likely to cause flooding even if it doesn’t develop into a tropical cyclone. As all this moisture collides with a stalled cold front just inland of the Gulf Coast, it will trigger excessive rainfall regardless of storm organization.

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