Melissa is expected to bring heavy rainfall and the risk of significant flash flooding and the danger of landslides to portions of Haiti and the Dominican Republic through the weekend.

Tropical Storm Melissa formed in the Caribbean Sea on Tuesday as forecasters warned that heavy rain, flooding and strong winds could hit Haiti and Jamaica later this week.

"The longer Melissa tracks to the west, the greater the chance of an impact on the U.S.," AccuWeather Chief Meteorologist Bernie Rayno said.