Tropical Depression Five Strengthens Into Tropical Storm Dorian

Former Tropical Depression Five strengthened into Tropical Storm Dorian east of the Lesser Antilles on Saturday afternoon.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Dorian was located at latitude 10.7°N and longitude 49.1°W which put it about 725 miles (1165 km) east southeast of Barbados.  Dorian was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 1008 mb.

The circulation around former Tropical Depression Five exhibited greater organization on Saturday afternoon and the National Hurricane Center determined that the system had strengthened to Tropical Storm Dorian.  A band of thunderstorms close to the center of circulation wrapped around the western and southern sides of the center.  The strongest winds were occurring in that band of storms.  Other bands in the western half of the circulation started to revolve around the center of circulation.  Storms near the center began to generate upper level divergence which was pumping mass away to the west of the tropical storm.  The circulation around Tropical Storm Dorian was small.  Winds to tropical storm force extended out about 25 miles (40 km) from the center of circulation.

Tropical Storm Dorian will move through an environment that will be favorable for intensification during the next several days.  Dorian will move over water where the Sea Surface Temperature is near 28°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear.  The shear will slow the rate of intensification.  Tropical Storm Dorian will move south of a region of drier air.  If drier air is pulled into the circulation, it will interrupt intensification.  Since Tropical Storm Dorian is so small, it could strengthen or weaken very quickly if the environment changes.  Dorian could strengthen into a hurricane in two or three days.

Tropical Storm Dorian will move south of a subtropical high pressure system over the Atlantic Ocean.  The high will steer Dorian toward the west-northwest during the next few days.  On its anticipated track Tropical Storm Dorian could approach the Lesser Antilles on Tuesday.  Dorian could strengthen into a hurricane by that time.  Watches and/or warnings could be issued for parts of the Lesser Antilles on Sunday.