Tropical Storm Dorian moved toward Puerto Rico on Tuesday. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Dorian was located at latitude 16.0°N and longitude 63.0°W which put it about 275 miles (440 km) east-southeast of Ponce, Puerto Rico. Dorian was moving toward the northwest 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 1006 mb.
A Hurricane Watch was issued for Puerto Rico. Tropical Storm Warnings were in effect for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands and the British Virgin Islands. A Tropical Storm Watch was issued for the coast of the Dominican Republic from Isla Saona to Puerto Plata.
The original low level center of Tropical Storm Dorian passed south of Barbados and St. Lucia on Tuesday morning. Dorian dropped heavy rain and there were reports of flash floods on Martinique. The original center weakened on Tuesday afternoon and a new low level center formed about 60 miles farther to the north. The formation of a new center of circulation caused the forecast future track of Tropical Storm Dorian to be shifted northward as well.
Even with the formation of a new center of circulation, the overall circulation around Tropical Storm Dorian did not change much on Tuesday. The circulation around Dorian remained small. Winds to tropical storm force only extended out about 45 miles (75 km) from the center of circulation. A broken ring of thunderstorms surrounded the new low level center. Bands of showers and thunderstorms were revolving the center of Tropical Storm Dorian. Storms near the center were producing upper level divergence which was pumping mass away to the north of the tropical storm.
Tropical Storm Dorian will move through an environment somewhat favorable for intensification on Wednesday. Dorian will move over water where the Sea Surface Temperature is near 29°C. An upper level low northwest of Puerto Rico will produce southerly winds which will blow toward the top of the circulation. Those winds will cause some vertical wind shear, which will inhibit intensification. A large mass of drier air is north of Tropical Storm Dorian and the drier air could also inhibit intensification if it gets pulled into the circulation around Dorian. The small size of the circulation around Tropical Storm Dorian means that it could weaken or strengthen quickly if the environmental conditions change significantly. Dorian is likely to weaken when it crosses Puerto Rico on Wednesday night.
The upper low northwest of Puerto Rico will help to steer Tropical Storm Dorian toward the northwest on Wednesday. On its anticipated track Tropical Storm Dorian could reach Puerto Rico by Wednesday evening. Dorian will bring gusty winds and it will drop locally heavy rain on Puerto Rico. Locally heavy rain could cause flash floods in some locations. A high pressure system will build north of Tropical Storm Dorian on Thursday and Friday. The high will turn Dorian back toward the west-northwest. Dorian could approach the east coast of Florida on Sunday.
Elsewhere over the Atlantic Ocean, Tropical Depression Six strengthened into Tropical Storm Erin southeast of Cape Hatteras on Tuesday night. At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Erin was located at latitude 31.9°N and longitude 72.1°W which put it about 300 miles (485 km) southeast of Cape Hatteras, North Carolina. Erin was moving toward the west at 2 m.p.h. (3 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. (65 km/h). The minimum surface pressure was 1005 mb. Tropical Storm Erin is forecast to move northeast toward Nova Scotia.