"Some additional weakening is likely while Oscar moves across the mountainous terrain of eastern Cuba, but Oscar is forecast to be a tropical storm when it moves north of Cuba late today and then moves near the southeastern and central Bahamas on Tuesday," the hurricane center said Monday morning.

Up to 20 inches of rain is forecast in some regions of Cuba, which could trigger flash flooding and mudslides.

Tropical Storm Oscar remained crouched over eastern Cuba, where it could drop more than a foot of rain as it crawls over the island nation at 3 mph. Oscar was a tiny, weak storm, with tropical-storm-force winds extending just 45 miles from the center and maximum sustained winds at 40 mph.