Tropical storm DON
Tuesday 18th July 2017
Disturbance Fifteen took the window of opportunity and formed Tropical Storm DON overnight. This is now about 300 miles east of Trinidad, still westbound at about 17 knots. This storm ran into upper level shear almost immediately and is now at peak intensity with a hurricane severity index rating of 3 out of a possible 50 points (1 for size and 2 for intensity). In real terms, this is producing steady winds of 40 knots gusting 65 in places. Tropical storm conditions may be expected across the Netherlands Antilles tonight and tomorrow. This storm will dissipate fairly quickly and no deviation from a beeline across the extreme southern Caribbean is expected. Fast ground speed should keep flooding risks to a minimum. If DON slows down, then some parts of the Netherlands Antilles could receive up to eight inches tonight, but if the current speed is maintained, considerably less.
The other potential storm we picked up yesterday was Disturbance Seventeen. This is now is now about 500 miles north east of the mouth of the Amazon and quite well-defined but already curving to the north-west where upper level wind shear awaits. This won't reach the islands of the north eastern Caribbean and may turn north and miss land altogether.
Storms cones aloft in Curacao then.