Displaced rain from what was Tropical Storm Arthur in Texas has started moving ashore in Louisiana.
"Significant, potentially life-threatening flash flooding is likely," the National Weather Service warned.
The worst of the downpours are expected from around midnight until 7:00am on Thursday morning.
"The risk for flash flooding will continue into Friday along and north of the I-10/12 corridor."
Forecasters say isolated spots could get 10 inches of flooding rains.
The Storm Prediction Center, however, is forecasting most of the region will see less than six inches of rain.
NWS
The Weather Service says even after the heaviest rain moves out, rivers on the Northshore will keep rising from runoff.
"Significant rises to local creeks and rivers are expected."
Officials are urging people to stay inside.
"Heavy rain will be affecting all parts of Central and South Louisiana," Governor Jeff Landry advised. "I urge you to stay off the roads during heavy downpours."
