Melissa is expected to strengthen from a tropical storm into a major hurricane and bring "catastrophic" flash flooding and landslides to Jamaica, Haiti and the Dominican Republic

Melissa, with maximum winds of 70 mph and stronger gusts, should attain hurricane status later Oct. 25 and become a major hurricane by Sunday, the National Hurricane Center said Saturday morning. A tropical storm becomes a hurricane when its winds reach 74 mph.

After it lashes the Caribbean this weekend, there’s still uncertainty about where the storm will go next. Here are the scenarios, one day at a time.

Tropical Storm Melissa is expected to strengthen into a hurricane, threatening the northern Caribbean with massive rainfall and life-threatening flooding

Tropical Storm Melissa continues to slowly move northwest with sustained winds near 70 mph -- just shy of becoming the fifth hurricane of this Atlantic season.

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

The base commander on Saturday expanded a previous evacuation order to include “non-mission-essential U.S. citizens.”

The storm is expected to hit Jamaica, Haiti and the Dominican Republic, as well as Cuba, the Bahamas, and the Turks and Caicos.