Former Tropical Depression Seven strengthened to Tropical Storm Fiona on Wednesday evening and Tropical Storm Watches were issued for the Leeward Islands. At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Fiona was located at latitude 16.7°N and longitude 52.0°W which put it about 650 miles (1045 km) east of the Leeward Islands. Fiona was moving toward the west at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1002 mb.

Tropical Storm Watches were in effect for Saba, St. Eustatius, St. Maarten, Antigua, Barbuda, St. Kitts, Nevis, Montserrat and Anguilla.

Remotely sensed data gathered by satellites indicated that the circulation around former Tropical Depression Seven had strengthened on Wednesday evening and the National Hurricane Center upgraded the system to Tropical Storm Fiona. The distribution of thunderstorms in Tropical Storm Fiona was asymmetric. Almost all of the thunderstorms were occurring in bands in the eastern half of Fiona’s circulation. Bands in the western half of the circulation consisted primarily of showers and lower clouds. Storms in the eastern half of the circulation generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 140 miles (220 km) on the eastern side of Tropical Storm Fiona. The winds in the western half of the circulation were blowing at less than tropical storm force.

Tropical Storm Fiona will move through an environment somewhat favorable for intensification during the next 36 hours. Fiona will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western part of an upper level ridge over the tropical Atlantic Ocean. The ridge will produce southwesterly winds that will blow toward the top of Fiona’s circulation. Those winds will cause some vertical wind shear and the wind shear will inhibit intensification. Tropical Storm Fiona could intensify if the upper level winds weaken.

Tropical Storm Fiona will move around the southern side of the subtropical high pressure system over the Atlantic Ocean. The high pressure system will steer Fiona toward the west during the next 48 hours. On its anticipated track Tropical Storm Fiona could approach the Leeward Islands on Friday afternoon. Fiona could bring gusty winds and locally heavy rain to the northern Leeward Islands.