A storm system expected to strike a handful of southern states this weekend is looking more and more menacing.

More than 18 million people in Louisiana, Arkansas, Texas and Oklahoma will be at an enhanced threat of storms that could include strong tornadoes and flooding rains, the national Storm Prediction Center said.

The area includes several major Texas cities including Dallas, Houston and Austin.

A more tightly defined area that includes the Louisiana cities of Shreveport and Monroe and stretches into northeast Texas will be at an even greater risk of damaging winds on Friday, the Norman, Oklahoma-based Storm Prediction Center warned.

Most of Mississippi is expected to have a high chance of severe weather as the front moves across the state late Friday and into early Saturday.

A key concern in this area is the likelihood of “a relatively focused corridor for damaging wind,” the Storm Prediction Center warned in a Thursday briefing.

Wicked weather will pose a threat to New Orleans, along with Alabama and Georgia as the system moves eastward on Saturday, forecasters said.

Heavy rains could also cause flooding across the South and part of the Midwest.

The latest forecasts call for up to 4 inches (10 centimeters) of rain in parts of Texas and southeast Oklahoma, according to the National Weather Service.

Many streams already are at or near flood levels because of earlier storms, and heavy rains could lead to flash flooding across the region, forecasters said. Parts of Texas, Oklahoma, Arkansas, Missouri and southern Illinois were under a flash flood watch on Thursday in anticipation of the drenching rains.

The weekend storms are expected to arrive as thousands of football fans are traveling to New Orleans for Monday night’s national championship college football game between Louisiana State University and Clemson University.

New Orleans will be at an enhanced risk of severe weather Saturday, and more thunderstorms are expected on game day Monday, authorities said.

The Governor’s Office of Homeland Security & Emergency Preparedness will activate its Crisis Action Team Friday night through Monday night, said Mike Steele, a spokesman with the agency. That involves having staff on duty to support local governments in need of help dealing with emergencies, he said.

“We’re trying to tell the public, ‘look we have a lot going on weather-wise this weekend, plus potentially more weather issues Monday in addition to the national championship game,” Steele said. “Stay weather aware, keep phones charged, pay attention to local media.”

The Saturday storms could bring winds of up to 70 mph to parts of Alabama as they move east, the National Weather Service’s Birmingham office said.

Southeast Louisiana — including the New Orleans metro area — and large parts of Mississippi and Alabama will be most at risk on Saturday.