(This story, originally posted at 11 p.m. Monday, was updated at 11 a.m. Tuesday.)

Tropical Storm Don, which formed late Monday, weakened Tuesday morning and is barely hanging on as a tropical storm. It is forecast to blow through the Windward Islands late Tuesday, unleashing a blitz of gusty winds and heavy rain. By Wednesday or Thursday, forecasters call for its swift demise.

Positioned about 150 miles southeast of Barbados, Don is a minimal tropical storm, with peak wind speeds of 40 mph. Little change in strength is predicted Tuesday as it approaches Grenada and St. Vincent and the Grenadines, where tropical storm warnings are in place.

Dons health is not particularly good. The National Hurricane Center said in its 11 a.m. discussion that it had become less defined and that it may lack the requisite qualification to be considered a tropical storm: a closed center of circulation.

The storm is moving fast, toward the west at 20 mph. Arrival in the Windward Islands the chain of islands at the intersection of the tropical Atlantic Ocean and the Caribbean (along the southern end of the island group known as the Lesser Antilles) is expected tonight.

Don could unleash a brief period of tropical-storm-force winds and put down three to six inches of rain on these islands Tuesday and Tuesday night. Flash floods and mudslides are possible, especially in mountainous areas.

Tropical storm watches are in effect for Barbados and Bonaire. In addition, interests in Trinidad and Tobago, Aruba, and Curacao should monitor the progress of Don, the Hurricane Center said.

Once Don crosses these islands and enters the Caribbean, it is not expected to survive for long. Hostile wind shear is expected to shred apart its vulnerable core.

Increasing westerly shear and dry mid-level air are likely to continue to weaken the tropical cyclone, the Hurricane Center said in its 11 a.m. discussion Tuesday. The forecast calls for Don to weaken to a tropical depression in about 24 hours and degenerate into a an open wave within 36 hours.

Don, the fourth named storm of the 2017 hurricane season, arrived more than a month ahead of average.

Meanwhile, in the eastern tropical Pacific Ocean, a new tropical depression formed which is likely to be named Tropical Storm Hilary some time Tuesday.

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Tropical Storm Don weakening on approach to Windward Islands, forecast to 'degenerate' - Washington Post