Across the region, officials ordered schools, airports and even casinos to close and they prepared shelters ahead of the storm, which was not expected to strengthen over the next two days.
Early Thursday morning, Erika was located about 30 miles (45 kilometers) southeast of Antigua and was moving west at 16 mph (26 kph) with maximum sustained of 50 mph (85 kph), according to the U.S. National Hurricane Center in Miami.
Authorities in Antigua and Barbuda warned of flash floods given the extremely dry conditions caused by the worst drought to hit the Caribbean in recent years. Boats at Shell Beach Marina on Antigua's north coast have been out of the water since Saturday, with people not taking chances as Erika approaches, said Caroline Davy, a marina employee.
She said many people were caught off-guard when Tropical Storm Gonzalo battered Antigua last October.
"Too many times we've seen things happen that were not predicted," she said.
Authorities in the nearby Dutch Caribbean territory of St. Maarten said schools and government offices would close Thursday. They also asked that casinos, restaurants and other businesses close by midnight Wednesday. Officials warned they might temporarily suspend power and water service as the storm approaches.
The hurricane center said Erika would move near Puerto Rico and the Virgin Islands on Thursday and be near or just north of the Dominican Republic on Friday.
All airports in the U.S. Virgin Islands would be closed to incoming flights until Friday, and government offices would close as well, said Gov. Kenneth Mapp.
"This is a fast-moving storm, and so we expect conditions to deteriorate rapidly," he said.
Tropical storm warnings were issued for Puerto Rico, the U.S. and British Virgin Islands and the Leeward Islands. A tropical storm watch was in effect for the northern Dominican Republic, the Turks & Caicos Islands and southeastern Bahamas.
The storm was expected to be near South Florida by Monday, according to James Franklin, chief hurricane forecaster at the Miami-based center. But its intensity was still uncertain.
"We don't know how much of the storm will be left," he said, adding that it faces strong upper-level westerly winds in the next two to three days.
Meanwhile in the Pacific, Ignacio strengthened into a hurricane. The storm's maximum sustained winds increased Thursday morning to 85 mph (140 kph).
Hurricane Ignacio was centered about 1,205 miles (1,940 kilometers) east-southeast of Hilo, Hawaii, and was moving west-northwest near 13 mph (20 kph).
Also in the Pacific, a new tropical storm formed Thursday morning. Tropical Storm Jimena had maximum sustained winds near 40 mph (65 kph) and was expected to strengthen to a hurricane Friday. Jimena was centered about 845 miles (1,365 kilometers) south-southwest of the southern tip of Mexico's Baja California peninsula.
Associated Press writer Judy Fitzpatrick in Philipsburg, St. Maarten, contributed to this report.