By CURTIS MORGAN
cmorgan@MiamiHerald.com

Hurricane Tomas began weakening on Sunday, a trend that could reduce it to a tropical storm over the next few days. But it was expected to regain strength during what looms as a slow, weeklong march toward the Caribbean’s largest islands.

Forecasters at the National Hurricane Center, stressing that Tomas’ path remains uncertain four to five days out, drew a large potential strike zone around an area covering Jamaica, eastern Cuba and much of Hispaniola.

Smack in the middle: Haiti, which shares Hispaniola with the Dominican Republic, and is still reeling from a devastating January earthquake that left more than 1 million people homeless and living in tents.

At 5 a.m. Sunday, Tomas’ sustained winds were 75 mph, significantly down from an earlier 100 mph, Category Two peak. The hurricane also was showing other signs of weakening as it encountered wind shear and dry air that forecasters expected to reduce it to a tropical storm by Monday. But with lots of warm water in its path, the hurricane center still predicted steady intensification.

By Wednesday, it could be a hurricane again, just as it is expected to begin making a turn toward the north on a track toward the southwestern coast of Haiti, steered by a strong trough pushing in from the United States. The timing of that turn remains uncertain, however, and Tomas could veer further west toward Jamaica and Cuba or east toward the Dominican Republic.

The storm moving west at 12 mph, its center 290 miles south-southeast of San Juan and 570 miles south-southeast of Port-au-Prince.