Former Tropical Storm Tammy strengthened to a hurricane east of the Lesser Antilles on Friday morning. At 11:00 a.m. EDT on Friday the center of Hurricane Tammy was located at latitude 14.1°N and longitude 58.6°W which put it about 165 miles (265 km) east-southeast of Martinique. Tammy was moving toward the west-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 992 mb.

Hurricane Warnings were in effect for Guadeloupe, Antigua, Barbuda, Montserrat, St. Kitts, and Nevis. Hurricane Watches were in effect for Anguilla, St. Maarten, St. Martin, and St. Baarthelemy. Tropical Storm Warnings were in effect for Dominica, Anguilla, St. Maarten, St. Martin, St. Barthelemy, Saba and St. Eustatius. Tropical Storm Watches were in effect for Martinique and Barbados.

U.S. Air Force Reserve and NOAA planes flying in former Tropical Storm Tammy found that Tammy had intensified to a hurricane on Friday morning. A circular eye with a diameter of 14 miles (22 km) formed at the center of Hurricane Tammy. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Hurricane Tammy. Storms near the core generated upper level divergence that pumped mass away from the hurricane. The removal of mass caused the surface pressure to decrease on Friday morning.

Winds to hurricane force extended out 25 miles (40 km) in the northeastern quadrant of Hurricane Tammy. Winds to tropical storm force extended out 140 miles (220 km) in the eastern side of Tammy’s circulation. Winds to tropical storm force extended out 90 miles (145 km) in the western side of the circulation.

Hurricane Tammy will move through an environment somewhat favorable for intensification during the next 24 hours. Tammy will move over water where the Sea Surface Temperatures are near 30°C. It will move under the far eastern part of an upper level low over the Eastern Caribbean Sea. The upper level low will produce southwesterly winds that will blow toward the top of Tammy’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but it will not be strong enough to prevent intensification. Hurricane Tammy is likely to intensify during the next 24 hours.

Hurricane Tammy will move south of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Tammy toward the northwest during the next 24 hours. On its anticipated track, the center of Hurricane Tammy could be near Guadeloupe on Saturday morning.

Hurricane Tammy is likely to bring strong winds and locally heavy rain to the central and northern Leeward Islands. Heavy rain is likely to cause flash in some locations. Hurricane Tammy could cause a storm surge of up to seven feet (two meters) along the coasts of some of the islands.