The National Hurricane Center's 5 p.m. Friday update reported that Tropical Storm Melissa is in the Caribbean Sea, 215 miles southeast of Kingston Jamaica and 225 miles southwest of Port Au Prince Haiti. Packing maximum sustained winds of 65 mph, it is tracking north at 2 mph. Melissa is expected to strengthen into a hurricane.

Heavy rain is expected across Jamaica, where "precipitation totals from multiple models suggest that storm totals exceeding 24 inches and localized amounts above 30 inches are quite possible," noted meteorologists Bob Henson and Jeff Masters in their blog Eye on the Storm.

Jamaica and other parts of the Caribbean are staring down what could become a catastrophic, days-long assault of extreme rainfall and damaging winds.

The hot ocean temperatures and dry air are primed for a potentially explosive hurricane to erupt, with some severe weather impacts possible for Florida.

Although Jamaica has been hit by many hurricanes, a storm stronger than Category 3 has never made landfall on the island.

Tropical Storm Melissa is barely moving through the Caribbean, and that’s exactly what makes it so dangerous. The longer it lingers, the more rain it dumps. Haiti, Jamaica and the Dominican Republic could face days of relentless downpours and mudslides.