Tropical Storm Tammy strengthened east of the Lesser Antilles on Thursday morning. At 8:00 a.m. EDT on Thursday the center of Tropical Storm Tammy was located at latitude 13.5°N and longitude 55.1°W which put it about 465 miles (745 km) east of Guadeloupe. Tammy was moving toward the west at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h). The minimum surface pressure was 1004 mb.

Tropical Storm Watches were in effect for Barbados, Dominica, Martinique, Guadeloupe, Antigua, Barbuda, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius.

A NOAA research plane found that Tropical Storm Tammy had strengthened during Wednesday night. More thunderstorms developed near the center of Tammy’s circulation. However, the distribution of thunderstorms was still asymmetrical. Many of the thunderstorms were occurring in bands in the eastern side of Tropical Storm Tammy. Bands in the western side of Tammy’s circulation consisted primarily of showers and lower clouds. Storms near the center of circulation generated upper level divergence that pumped mass away to the north and east of the tropical storm. Winds to tropical storm force extended out 140 miles (220 km) in the eastern side of Tropical Storm Tammy. Winds to tropical storm force extended out 70 miles (110 km) in the western side of Tammy.

Tropical Storm 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. The winds in the lower levels of the atmosphere are blowing from the east. The difference in wind direction between the upper and lower levels of the atmosphere will cause moderate vertical wind shear. The wind shear will inhibit intensification. Tropical Storm Tammy could intensify gradually during the next 24 hours.

Tropical Storm Tammy will move south of a subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Tammy toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Storm Tammy could approach the central and northern Leeward Islands on Friday.

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