Late Thursday, August 2, a tropical depression located about 300 miles west of the Windward Islands of the Lesser Antilles (southwest Caribbean) developed into the fifth named storm of the 2012 Atlantic Hurricane Season – Tropical Storm Ernesto.
According to the National Hurricane Centre (NHC) on Friday, August 3, the center of Ernesto was located over the St. Vincent Passage in the Windward Islands of the Lesser Antilles – approximately 30 miles southeast of St Lucia and around 35 miles east-north east of St. Vincent. The NHC report that at this time Ernesto had maximum sustained winds of 45 mph – the equivalent of a Tropical Storm on the Saffir-Simpson Hurricane Wind Scale (SSHWS). The system was also reported to have a minimum central pressure of approximately 1004mb, and was moving very quickly towards the west at 24 mph. Tropical storm force winds were extending outwards up to 115miles from the center of Ernesto (predominantly to the north and east of the system).
Preliminary information on the extent of the system’s wind field indicates that tropical storm winds are extending over St. Lucia and southern portions of Martinique. A tropical storm warning is in effect for Dominica, (St Lucia, Martinique) and Guadeloupe (meaning that tropical storm conditions are expected within the next 12 hours). The system is expected to bring total rain accumulations of between 2 to 3 inches to portions of the Windward Islands through the day.
Ernesto is forecast to continue tracking towards the west over the next couple days over the Caribbean Sea, with a gradual decrease in forward speed, before shifting to a more west-northwest direction and passing around 70 miles south of Jamaica and the Cayman Islands on Monday and Tuesday. Under the NHC forecast the center of Ernesto will be located offshore of the Yucatan Peninsula, Mexico early (UTC) Wednesday. The NHC official forecast track is in the middle of the model track guidance envelope. It is too early to tell whether Ernesto will impact the U.S.
Under the NHC forecast, Ernesto is forecast to strengthen to hurricane status in around 72 hours when the system makes its closest pass to Jamaica and is forecast to be a Category 1 hurricane as it approaches Mexico. NOAA’s sea surface temperatures in the Caribbean Sea are around 28oC and wind shear is forecast to decrease over the weekend – conditions which are conducive for strengthening. The majority of models are strengthening Ernesto to hurricane status, though the timing of the strengthening varies from Sunday to Tuesday.