(AP) -- A storm system expected to strike southern states from Texas to Georgia this weekend is looking more and more menacing, bringing the potential for devastating tornadoes and 80-mph wind gusts.
The national Storm Prediction Center said 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 area includes several 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. A key concern in this area is the likelihood of "a relatively focused corridor for damaging wind," the Storm Prediction Center warned in a briefing Thursday.
"We could see some very strong tornadoes — possibly those that may stay on the ground for some time — not just the brief spin-up tornadoes," Matt Hemingway, a weather service meteorologist in Shreveport, said.
Wind gusts of up to 80 mph (130 kph) will be possible in Louisiana as the storms move through, the National Weather Service said.
"All modes of severe weather appear to be in play with this system, including the threat of tornadoes in addition to large hail and damaging winds," forecasters at the weather service's Shreveport office said in a briefing on the incoming system.
Wicked weather also will pose a threat to Alabama and Georgia as the system moves eastward on Saturday, forecasters said.
Heavy rains also could 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.