Tropical Storm Bret strengthened slightly overnight and is forecast to reach the Lesser Antilles on Thursday morning as a strong tropical storm.
Bret poses no threat to the US mainland as of Wednesday morning.
With winds of 60 mph, Bret is about 645 miles east of the Windward Islands. It's expected to bring strong winds, torrential downpours that could lead to flash flooding and rough surf to parts of the Caribbean.
Track Tropical Storm Bret
A tropical storm warning is in effect Wednesday for St. Lucia, meaning tropical storm conditions are possible within 36 hours. Tropical storm watches are in effect for Barbados, Dominica and Martinique, meaning tropical storm conditions are possible there within 48 hours.
"Interests elsewhere in the Lesser Antilles should monitor the progress of Bret," the National Hurricane Center said. "Additional watches or warnings will likely be required for these islands today."
While the storm is still pretty ragged and a little disorganized, residents and tourists should prepare, the hurricane center said.
How to prepare for hurricane season
"Some additional strengthening is possible during the next day or so," it said.
While tropical-storm-force winds extend 60 miles from Bret's center, it's still too early to know where that center will be as the storm crosses over the islands, the hurricane center said.
Up to 6 inches of rain is possible, with isolated amounts as high as 10 inches for portions of the Lesser Antilles from Guadeloupe south to Grenada, including Barbados. This could lead to flash flooding, especially across areas of higher terrain, the hurricane center said.
"An Air Force Hurricane Hunter aircraft is scheduled to investigate Bret this afternoon, and should provide a better estimate of the storm's intensity and structure," it said early Wednesday.
"The tropical cyclone is likely to begin weakening in a couple of days, and global models are in good agreement that the system will degenerate into a wave as it approaches the western Caribbean Sea," the hurricane center explained.
2nd named storm of 2023 hurricane season
Bret is the second named storm of the 2023 Atlantic hurricane season.
A near-average number of storms is forecast this year: 12 to 17 named storms, five to nine hurricanes and up to four major hurricanes of Category 3 or higher, the National Oceanic and Atmospheric Administration has said.
If Bret had strengthened into a hurricane, it would have been a rarity. The season's first hurricane usually doesn't form until early to mid-August, according to the hurricane center.