The Dominica Meteorological Service has reported that at 5pm, Tropical Depression number 9 was upgraded to Tropical Storm Isaac in the Central Atlantic.
At 500 PM, the center of the storm was located near latitude 14.5 North, longitude 36.6 West.
This system, the Met Office says, is projected to begin affecting the Lesser Antilles by the middle of next week. On the present track, Isaac is expected to begin affecting Dominica on Wednesday and passing near to or over Dominica on Thursday.
Residents are advised to closely monitor the progress of Isaac.
Isaac is moving toward the west near 7 mph (11 km/h). A westward motion with an increase in forward speed are expected during the next few days. Maximum sustained winds have increased to near 40 mph (65 km/h) with higher gusts.
Additional strengthening is forecast during the next few days, and Isaac could become a hurricane by Monday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 1005 mb (29.68 inches).
Meantime according to the weather outlook for Dominica, a weak high pressure system is expected to be the dominant feature across the area, tonight into tomorrow. Light winds and daytime heating could produce some cloudiness, localized showers and a slight chance of isolated thunderstorms by tomorrow afternoon. By evening, a surface to low-level trough associated with Tropical Storm Florence is expected to move through the area.
Moderate seas are expected during the next 24 hours with waves peaking up to 5.0ft.