Tropical Storm Tammy forms in tropical Atlantic heading toward group of islands, forecasters say

MIAMI — Tropical Storm Tammy formed Wednesday afternoon in the Atlantic Ocean, putting a group of islands on alert for its expected approach.

The Miami-based National Hurricane Center said Tammy was centered at 5 p.m. EDT about 625 miles east of the Windward Islands. It was moving briskly to the west at 23 mph and expected to gradually strengthen in coming days.

Tropical storm watches have been issued for Barbados, Dominica, and Martinique and Guadeloupe. Forecasters said tropical storm conditions were possible in the region starting within 48 hours and that further watches and warnings will likely be required Wednesday night or Thursday.

Tammy is initially expected to spread heavy rains over the northern Windward and Leeward Islands through Friday and then across the U.S. and British Virgin Islands and Puerto Rico over the weekend, according to the hurricane center.

The center’s opening advisory on Tammy said total rainfall could measure between 3 and 6 inches (7-14 centimeters) with maximum amounts of 10 inches (25 centimeters) in some spots in the northern Windward Islands and Leeward Islands. Lesser rainfall amounts are expected in the British and U.S. Virgin Islands into eastern Puerto Rico, the hurricane center added.

The prospect of heavy rains as Tammy nears those islands raises a threat of scattered flash flooding, urban flooding and isolated mudslides in higher terrain, according to meteorologists.