(CNN) Flooding has hit parts of the South hard this week, and forecasts suggest Texas and neighboring states remain under threat -- particularly in areas that have already seen heavy rainfall.
Nearly 20 million people were at risk of flash flooding, according to CNN meteorologist Dave Hennen, from southeast Texas into much of Louisiana and southern Arkansas.
The Houston metro area was forecast to receive heavy rainfall in the coming days, with a flash-flood watch set to go into effect Thursday afternoon and stretch into the weekend, said the National Weather Service's office in the Texas city.
Those affected could expect widespread rainfall totals of 5 to 8 inches, with 9 to 12 inches possible in other areas, the service said on Twitter.
Flash-flood warnings were already in effect Thursday morning from northern Louisiana into southern Arkansas, CNN's Hennen said. The same areas could see the threat of flooding continue into Friday and Saturday, and will likely receive additional rainfall totals of 3 to 8 inches.
The threat of severe thunderstorms also extended from Texas into the Ohio Valley, Hennen said.
The impact of the flooding has been particularly bad in Texas, where at least one man was confirmed dead in Austin after floodwaters swept him away.
Emergency responders were called to a water rescue Wednesday afternoon, officials said. The body of a man, about 50 years of age, was recovered in Lady Bird Lake. The man was reported dead at the scene.
In Houston, the search for missing 4-year-old Maleah Davis resumed Thursday morning after authorities had put it on hold due to the severe weather, Texas EquuSearch said.
Flooding also prompted water rescues in Bossier City, Louisiana, just east of Shreveport, according to CNN affiliate KTBS. Firefighters had rescued at least 19 people from their homes by early Thursday.
The US Army Corps of Engineers recommended that the Bonnet Carre Spillway be opened on May 14 for the second time this year due to flooding concerns along the Mississippi River, to help divert rising water away from New Orleans. That decision would ultimately be left up to the commanding general, officials said.
It would be the first time in history the spillway was used twice in one season, Major Jordan Davis, a US Army Corps of Engineers spokesman said in a press conference Thursday. The spillway was last opened in March.
"Above all, the safety of the public is our main concern, and it weighs the heaviest in our decision," Davis said.