About 120 miles of Florida's (search) Atlantic coast were under a tropical storm warning Tuesday as a new system formed offshore and threatened to dump up to 15 inches of rain in parts of the state.

The tropical depression could strengthen into Tropical Storm Ophelia (search) by Wednesday, which prompted the warning from north of Jupiter to Titusville, according to the National Hurricane Center. It is expected to bring tropical storm conditions of wind of at least 39 mph to the state by Wednesday morning.

"The primary concern is very heavy rains," hurricane specialist Richard Pasch said. Five to 10 inches were expected over the next few days, with some isolated areas possibly getting 15 inches. The rain was expected to hit areas affected by last year's Hurricanes Frances and Jeanne. Much of the region has recovered but some homes remain covered in blue tarps as owners await new roofs.

Emergency management officials in St. Lucie and Indian River counties said they were monitoring the depression for developments but were not taking any protective action.

"Right now we're looking at this as a rain event," said Nathan McCollum, emergency management coordinator for Indian River County.

At 2 p.m. EDT, the depression had top sustained winds of about 30 mph and was centered about 180 miles southeast of Cape Canaveral. It wasn't moving, but it should start heading north-northwest later Tuesday.

Two other storms were out in the open ocean Tuesday as the busy hurricane season continues. Tropical Storm Nate (search) intensified south of Bermuda, while Hurricane Maria weakened on its way to the colder waters of the north Atlantic.

Nate, the 14th named storm of the season, was centered about 275 miles south-southwest of Bermuda with top sustained winds near 60 mph. Forecasters at the National Hurricane Center said it could reach hurricane strength, with winds of at least 74 mph, by Wednesday.

It wasn't moving, though it was expected to eventually make a turn to the northeast, forecasters said.

"Perhaps by the end of the work week it could be posing a threat to Bermuda, but not the U.S.," hurricane specialist Stacy Stewart said.

Maria peaked late Monday as a Category 3 hurricane with top wind speed at 115 mph. By 11 a.m. EDT, it was centered about 545 miles east-northeast of Bermuda with winds near 100 mph, forecasters said.

The hurricane was only a threat to shipping interests as it moved north-northeast near 7 mph, forecasters said.

Maria is the fifth hurricane of the Atlantic hurricane season. The season began June 1 and ends Nov. 30. Peak storm activity typically occurs from the end of August through mid-September.

Florida has been hit by six hurricanes since August 2004, including Katrina, blamed for 11 deaths in the state.