Tropical Depression Five formed about 800 miles east-southeast of Barbados on August 24th, 2019 at 11 am AST. At 5 PM AST, Tropical Depression Five was upgraded to Tropical Storm Dorian with maximum sustained winds of 40 mph, heading west-northwest as it was steered by a subtropical high pressure to the north.
There were competing environmental factors present favoring, as well as inhibiting strengthening. Favorable factors for strengthening included warm sea surface temperatures greater than 28ºC and light vertical wind shear less than 10 knots. In contrast, the inhibiting factor was very dry air above 6 km with relative humidity less than 50%, measured by a dropsonde from the hurricane hunter on the evening of August 25th. Dry air at 550 to 350 MB was being ingested into the storm from the south, limiting convection and subsequent development. READ MORE