Tropical Storm Ian Passes South of Jamaica

Tropical Storm Ian passed south of Jamaica on Saturday night. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Ian was located at latitude 14.7°N and longitude 77.7°W which put it about 395 miles (630 km) southeast of Grand Cayman. Ian was moving toward the west at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 1002 mb.

A Hurricane Warning was in effect for Grand Cayman. Hurricane Watches were in effect for the Cuban provinces of Isla de Juventud, Pinar del Rio and Artemisa. Tropical Storm Watches were in effect for Little Cayman and Cayman Brac. Tropical Storm Watches were also in effect for the Cuban provinces of La Habana, Mayabeque and Matanzas.

Tropical Storm Ian gradually got better organized on Saturday. More thunderstorms developed near the center of circulation. Bands of showers and thunderstorms formed and began to revolve around the center of Ian’s circulation. Storms near the center generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 60 miles (95 km) in the northern side of Ian. The winds in the southern half of Tropical Storm Ian were blowing at less than tropical storm force.

Tropical Storm Ian will move through an environment very favorable for intensification during the next 48 hours. Ian will move over water where the Sea Surface Temperatures are near 30˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Storm Ian is likely to intensify more quickly on Sunday. Tropical Storm Ian is likely to intensify to a hurricane during the next 24 hours. Ian could intensify rapidly after an inner core with an eye and an eyewall form. Ian could intensify to a major hurricane within 48 hours.

Tropical Storm Ian will move around the western end of a high pressure system over the western Atlantic Ocean. The high pressure system will steer Ian toward the northwest during the next 36 hours. On its anticipated track Tropical Storm Ian could be near Grand Cayman on Monday morning. Ian could be near western Cuba on Tuesday morning. Ian could be a major hurricane when it approaches western Cuba. Ian will move over the eastern Gulf of Mexico on Wednesday.

Elsewhere over the Atlantic Ocean, Tropical Storm Gaston brought wind and rain to the western Azores and Tropical Depression Hermine was weakening north-northeast of the Cabo Verde Islands.

At 11:00 p.m. EDT on Saturday the center of Tropical Storm Gaston was located at latitude 38.6°N and longitude 33.4°W which put it about 255 miles (410 km) west of the Faial, Azores. Gaston was moving toward the west at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 9979 mb.

Tropical Storm Warnings were in effect for Corvo, and Flores.

At 11:00 p.m. EDT on Saturday the center of Tropical Depression Hermine was located at latitude 22.9°N and longitude 20.3°W which put it about 535 miles (860 km) north-northeast of the Cabo Verde Islands. Hermine was moving toward the north at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1006 mb.