Tropical Storm Grace is forecast to mover over the Leeward islands Saturday night into Sunday, with tropical storm warnings for Antigua and Barbuda, Puerto Rico and the U.S. Virgin Islands.

The storm was moving west at 23 miles per hour with maximum sustained winds of 45 m.p.h., the center said in an advisory at 11 a.m., adding that Grace was about 265 miles east-southeast of the Leeward Islands.

Grace, the 7th named storm for this year’s Hurricane season, has been described as small storm but “moving quickly” and “gaining strength.”

Parts of the Dominican Republic were under a tropical storm watch, meaning tropical storm conditions are possible within 48 hours.