Tropical storm warnings were in effect on Wednesday for Puerto Rico and the Virgin Islands as Erika, the fifth named storm of the Atlantic hurricane season, closed in on the Eastern Caribbean and appeared to be heading for Florida, the U.S. National Hurricane Center said.

Erika strengthened slightly overnight and could reach hurricane status over Florida by Monday morning, the Miami-based government forecaster said, but its future intensity was uncertain due to possible wind disruption.

The Florida State Emergency Operations Center was partially activated on Wednesday as officials monitored the storm.

“We are preparing the protective and responsive measures we will need if the storm continues to develop out of an abundance of caution,” said Director Bryan W. Koon.

The state’s Division of Emergency Management issued an email notice to Florida residents and visitors advising them to keep an eye on local news for further instructions and to be sure they have disaster supply kits fully stocked and evacuation plans in place.

The storm was located about 285 miles (460 km) east-southeast of the island of Antigua, with maximum sustained winds of 45 miles per hour (72 kph). It was expected to near land by Wednesday night and reach Puerto Rico and the Virgin Islands on Thursday.

“The overall pattern is the most favorable I’ve seen in a long time for a potential Florida landfall,” said Bob Henson, a meteorologist who writes a blog for the private forecaster Weather Underground.

The last hurricane to hit Florida was Wilma in October 2005.

Tropical storm warnings and watches were also in effect for the islands of Guadeloupe, St. Martin/St Maarten, St. Barthelemy, Montserrat, Antigua and Barbuda, St. Kitts and Nevis, Anguilla, Saba and St. Eustatius.

The U.S. government’s annual forecast shows a quieter-than-normal 2015 Atlantic hurricane season, with six to 10 named storms and up to four reaching hurricane status of 74 mph (119 kph).

Last week the season’s first hurricane, Danny, while still far out at sea, reached Category 3 on the Saffir-Simpson scale of intensity. Winds of between 111 and 129 mph (178 to 208 kph) rapidly dissipated as the storm reached the Caribbean islands.

The Saffir-Simpson scale measures potential property damage from a storm, with hurricanes reaching Category 3 and higher considered “major,” with a potential for significant loss of life and damage. (Reporting by David Adams in Miami; Additional reporting by Koustav Samanta and Anupam Chatterjee in Bangalore; Editing by Lisa Von Ahn)