Tropical Storm Melissa moved slowly through the Caribbean, threatening Jamaica and southern Hispaniola with life-threatening flooding and landslides.

Authorities in the Dominican Republic and Jamaica opened shelters, closed schools and courts, and warned residents in flood-prone areas to seek higher ground.

The storm was producing up to 12 inches of rain in eastern Jamaica, with similar amounts expected in southern Haiti and the Dominican Republic, and heavy rain forecast for Aruba and Puerto Rico.

Moving west at 2 mph with 50 mph winds, Melissa could strengthen into a hurricane by Friday and a major hurricane by the weekend, NBC News has reported.

Melissa is the 13th named storm of the Atlantic hurricane season, which NOAA predicts will be above normal with multiple hurricanes expected.