The National Hurricane Center is tracking Invest99L as it moves over the central Caribbean Sea and gives the tropical rainstorm a 90% chance of developing into a tropical depression in the next two days.

Meteorologists have been tracking the storm for the past week, with its chances of forming increasing gradually. Tropical Storm Sara is expected to form by Thursday morning, becoming a hurricane by Friday night and a major hurricane by Saturday night, AccuWeather said.

A tropical disturbance building in the Caribbean Sea has been designated as Potential Tropical Cyclone 19 by the National Hurricane Center, and is forecast to strengthen into a tropical storm – known as Tropical Storm Sara – over the next few days.