Caribbean islanders are on the alert after reports from the National Hurricane Center reported Tropical Storm Isaac picking up speed over the Atlantic.

With a maximum sustained wind-speed of 112 km/h (70 mph), Isaac is traveling west at approximately 19 km/h (12 mph) and is expected to reach hurricane magnitude by Sunday night or midday Monday, latest reports show.

Meteorologists also cautioned residents of the Lesser Antilles saying that though the storm is expected to slow, it could cause some serious damage on route to the island before crossing into the eastern Caribbean Sea Thursday.

"While Isaac is forecast to begin weakening by Tuesday while it approaches the Lesser Antilles, it is still expected to be at or near hurricane intensity when it reaches the islands, and the uncertainty in the intensity forecast is higher than usual,” the National Hurricane Center said.

Senior AccuWeather expert Mike Doll said, "All interests in the Lesser Antilles should monitor the progress of this system closely.”

Meteorologists advised Puerto Rico, Hispaniola, Cuba, Jamaica, the Bahamas, and parts of the United States stay tuned to weather forecasts throughout the week.

Experts are also monitoring the developments of two hurricanes, Helene and Florence, spirally across the Atlantic. The former is traveling west at 20 km/h (13 mph ) with maximum sustained winds at 120 km/h (75 mph). The Cabo Verde Islands are on the alert where both a hurricane watch and tropical storm warning are in effect.

While the U.S. east coasts brace for heavy showers as Hurricane Florence is expected to slow to a tropical storm before hitting both Carolinas and Virginia by the end of the week.