HOUSTON -

Tropical Depression 9 strengthened into Tropical Storm Isaac Tuesday afternoon.

At 10 p.m. Tuesday, Isaac was located at 15.6 north and 55.6 west, or about 390 miles east of Guadeloupe with maximum sustained winds of 40 mph. It's moving west at 18 mph.

The government of Curacao issued a tropical storm warning for Saba, St. Eustatius and St. Maarten. The government of France has issued a tropical storm warning for Martinique.

A tropical storm watch is in effect for the British Virgin Islands, Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands.

"This is a big system and it's really starting to take shape," KPRC Local 2 chief meteorologist Frank Billingsley said.

Isaac should strengthen to a hurricane as it moves into the Caribbean, eventually becoming a category 2 storm before it reaches the Dominican Republic, Haiti, and Cuba by the weekend. These locations will likely be the hardest hit from the storm, if the current forecast plays out.

Also in the current forecast path is Florida. Should the storm make its predicted turn to the north after raking Cuba, Florida would be square in its sights. The mountains of Cuba would significantly weaken the storm, but Florida could face gusty winds and very heavy rain just in time for the Republican National Convention in Tampa next week.

One thing is almost certain: Isaac is not Houston's storm. While we can never say never, the odds of Isaac hitting the Texas coastline are very slim, so southeast Texas can breath a sigh of relief at this point.

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