Tropical Storm Don formed east of the Windward Islands on Monday. An Air Force Reserve Hurricane Hunter reconnaissance aircraft found a small, but well defined center of circulation in a cluster of thunderstorms formerly designated Invest 91L. Based on information from the recon plane, the National Hurricane Center classified the system at Tropical Storm Don. At 5:00 p.m. EDT on Monday the center of Tropical Storm Don was located at latitude 11.2°N and longitude 52.6°W which put it about 595 miles (955 km) east of Trinidad. Don was moving toward the west at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1009 mb.
A Tropical Storm Warning has been issue for Grenada. Tropical Storm Watches are in effect for Barbados, St. Vincent, the Grenadines and St. Lucia.
The reconnaissance plane found a small, tight center of circulation near the surface. A thin band of showers and thunderstorms wrapped partially around the western side of the center. Other thin bands of showers and thunderstorms were occurring north and west of the center. There were fewer showers and thunderstorms in the eastern half of Tropical Storm Don. The circulation of Tropical Storm Don is small and winds to tropical storm force only extend out about 25 miles (40 km) from the center of circulation. Thunderstorms in the band west of the center of circulation were generating some upper level divergence but it was not well developed.
Tropical Storm Don will move through an environment that will be somewhat favorable for intensification during the next several days. Don will move over water where the Sea Surface Temperature is near 29°C. An upper level ridge east of Don is generating easterly winds which are blowing over the top of the tropical storm. Those easterly winds are generating some vertical wind shear and the shear may partly explain why there are fewer showers and thunderstorms in the eastern half of the circulation. The shear will also inhibit intensification, but Tropical Storm Don could strengthen during the next 24 to 48 hours.
A strong subtropical high over the Atlantic Ocean is steering Tropical Storm Don toward the west and a generally westward motion is expected to continue during the next several days. On its anticipated track the center of Tropical Storm Don could pass south of Barbados on Tuesday. Tropical Storm Don could move over the southern Windward Islands on Tuesday night. Tropical Storm Don could bring gusty winds and locally heavy rain to the southern Windward Islands. Flash floods could occur in areas of steep terrain, if they receive locally heavy rainfall.