NEW YORK - Tropical Storm Fiona edged closer to the Caribbean islands, where it threatens to unleash flooding rains and mudslides by this weekend.

Fiona's top winds have reached 80 kilometres per hour and could peak at 105kmh as it meanders through the Caribbean into next week, the US National Hurricane Center said in an advisory.

The storm is the sixth of the 2022 Atlantic season, which began June 1.

Tropical storm watches have been posted for several Caribbean islands including St. Maarten, St Kitts and Montserrat, the centre said.

Additional watches and warnings could be raised for Puerto Rico, the US and British Virgin Islands and the Dominican Republic.

Dry air and wind shear are tearing at Fiona's structure, which could keep it from strengthening in the next few days, Mr Brad Reinhart, a hurricane specialist at the centre, wrote in a forecast.

After that, it's difficult to predict how strong the storm will get because it could be weakened by the mountains on Puerto Rico and Hispaniola.

The current forecast calls for Fiona to turn north next week, which would take it away from the energy-rich Gulf of Mexico and citrus groves in Florida. BLOOMBERG