Cindy, which had crossed Mexico's Yucatan Peninsula as a tropical depression, grew to tropical storm strength early Tuesday and had sustained wind of 50 mph by 11 a.m. The second storm became Tropical Storm Dennis as it developed wind of 40 mph. The minimum for a tropical storm is 39 mph.

Shell Oil Co. said 56 people were evacuated from offshore facilities in the Gulf of Mexico and Chevron Texaco said it had started evacuations. However, Shell said on its Web site that production was not affected.

Cindy could strengthen further before its center reaches the coast late Tuesday or early Wednesday, but it is not expected to become a hurricane, said the National Hurricane Center in Miami.

A tropical storm warning was posted along the coast from Intracoastal City, La., to the Florida Panhandle town of Destin.

The main danger would be if Cindy stalls along the coast, dumping heavy rain over a small area for an extended period, said sheriff's Capt. Mike Sanders in coastal St. Bernard Parish.

Water levels in canals had been lowered about a foot in anticipation of Cindy's arrival, said Windell Curole, general manager of the South Lafourche Levee District. The district covers one of the Louisiana coast's most vulnerable areas and includes a highway that leads to the Port Fourchon offshore petroleum terminal.

"If it stays a tropical storm, the worst that will happen is that we'll get a little water over the road," he said.

Officials ordered all recreational vehicles removed from the barrier island town of Grand Isle, La., a popular fishing spot. There is only one road out and the town wants the big, slow vehicles out of the way in case residents and tourists need to be evacuated later, said Ray Santiny, a city councilman and town clerk.

Officials on the Mississippi Gulf Coast said they were preparing for 6 to 10 inches of rain. Hancock County jail inmates were filling sandbags for distribution to flood-prone areas, said Dee Lumpkin of the county's Emergency Operations Center.

At 11 a.m. EDT, Cindy was centered about 165 miles south-southwest of the mouth of the Mississippi River and moving north around 14 mph. Tropical storm-force wind and rain extended up to 105 miles to the east of its center. It was expected to turn toward the north-northeast.

Dennis was centered about 355 miles south of San Juan, Puerto Rico, and moving west-northwest at about 18 mph.

It was on track to reach Haiti on Wednesday and South Florida on Friday, said hurricane center meteorologist Trisha Wallace. Tropical storm watches were posted for parts of Haiti and the Dominican Republic.

July 5 is the earliest date on record for four named storms to have formed in the Atlantic basin, the hurricane center said.

Elsewhere, Tropical Storm Dora in the Pacific was moving toward Mexico's southwest coast. It had maximum sustained wind of 40 mph and meteorologists did not expect it to strengthen significantly.