Latest Isaac tropical storm image from Harry Halstrom, Pond Hill forecaster.

MIAMI, Florida — The US National Hurricane Centre in its 8 a.m. tropical storm update reported Tropical Storm Isaac’s centre was 25 miles east of Dominica and 80 miles southeast of Guadeloupe. The storm has 45 mph sustained winds with higher-speed gusts. Little change in strength is expected over the next several hours.

While a tropical storm watch is in effect for St. Kitts and Nevis, at Pond Hill, Nevis, forecaster Harry W. Hallstrom said, “Isaac is getting ripped apart with wind shear. Satellite images show very little left as a recognizable tropical storm.

At 5 a.m. Thursday, Hallstrom said, “currently out the window it looks like just another day in Nevis. Some wind, no rain and rising sun.”

Isaac is moving west at 21 miles per hour. This general motion is forecast to continue today with a decrease in forward speed as it gets over the Caribbean Sea.

The Hurricane Centre says Isaac is nearly completely devoid of deep convection at the moment and is not trackable in radar data from Guadeloupe and Martinique.

Given the lack of deep convection to sustain the cyclone, continual gradual weakening is expected.

Isaac is forecast to move across the central Lesser Antilles and into the eastern Caribbean Sea Thursday, and then move across the eastern and central Caribbean Sea through Saturday.

Tropical Storm Isaac is expected to produce total rainfall accumulations of 2 to 4 inches with isolated amounts up to 6 inches across Martinique, Dominica, and Guadeloupe, especially over elevated terrain.

Rainfall of 0.5 to 1.5 inches with isolated amounts to 3 inches are forecast across Puerto Rico and the southern United States Virgin Islands, with up to an inch anticipated across the remaining Windward and Leeward Islands. This rainfall may cause dangerous flash flooding.

Tropical storm conditions are expected within the tropical storm warning area beginning within the next few hours through the afternoon. Tropical storm conditions are possible within the tropical storm watch area, also beginning late this morning.

Some coastal flooding is possible in areas of onshore winds. Near the coast, the surge will be accompanied by large waves.

Surf swells generated by Isaac are affecting portions of the Lesser Antilles. These swells are likely to cause life-threatening surf and rip current conditions.