A line of squalls moving in from the west will bring heavy, but brief rainfall to the New Orleans area.
The National Weather Service has issued a tornado watch through 2 a.m.
The storms could also bring high winds and the possibility of tornadoes.
The National Weather Service Storm Prediction Center has given the area a two out five on its risk level for severe weather.
"The potential for tornadoes is on the low side, but if they do develop, there's a bit of an elevated threat that they could become EF-1s, EF-2s," said Louisiana State Climatologist Jay Grymes.
And even if there are no tornadoes, Grymes said straight-line winds could be dangerously high.
"Damaging winds could be an issue," Grymes said, "and we've even got a flash-flood threat across the area."
The city of New Orleans waived parking restrictions through 8 a.m Thursday to allow drivers park on neutral grounds to avoid possible street flooding.
Detailed Forecast:
WEDNESDAY:
Weather Impact Alert: Partly sunny. Windy. Warm, humid. 30% chance daytime spotty showers. 100% chance rain and storms late night/overnight. High: 84. Winds: S 10-20 mph G30.
THURSDAY:
Much cooler and less humid. Windy. Mostly sunny. Low: S 53, N 50. High: 66.
FRIDAY:
Cold morning. Mostly sunny and mild. Low: S 49, N 39. High: 73.
SATURDAY:
Cool morning, warmer afternoon. Plenty of sun. Low: S 54, N 47. High: 76.
SUNDAY:
Partly cloudy. Some late clouds. Breezy. Warmer, more humid. Low: S 61, N 56. High: 81.
MONDAY:
Partly sunny. Much cooler, less humid. Breezy. Low: S 54, N 50. High: 66.
ST. PATRICK'S DAY:
AM patchy frost possible north. Partly cloudy. Cool, breezy. Low: S 45, N 38. High: 62.