MIAMI — A tropical storm warning was issued Sunday for parts of the Louisiana coast as a tropical depression formed in the northern Gulf of Mexico.

The warning was in effect from the mouth of the Mississippi River westward to Intracoastal City, the National Hurricane Center said. Tropical storm conditions were expected by Monday evening. New Orleans was not in the warning area.

A tropical storm watch was in effect west of Intracoastal City to Port O'Connor, Texas, including Galveston. That means tropical storm conditions were possible, generally within 36 hours.

"This is a time to, especially if you're farther west, assess where you are with your hurricane plan," hurricane specialist Eric Blake said.

Maximum sustained winds were near 35 mph in the small system. The depression could strengthen into a tropical storm by Monday, but it isn't currently expected to become a hurricane, Blake said. But he urged residents to pay attention anyway.

At 5 p.m. EDT, the depression's center was about 85 miles southeast of the mouth of the Mississippi River and about 415 miles east of Galveston, Texas. It was moving west near 6 mph and the center was expected to move parallel to the Louisiana coast Sunday night into Monday and approach the upper Texas coast on Tuesday.

Rainfall of 1 to 3 inches was expected in coastal Louisiana, with 2 to 6 inches forecast in southeast Texas. Tides of 2 to 4 feet above normal levels were expected in parts of the warning area.