Potential Tropical Storm Prompts Warnings for Puerto Rico, Virgin Islands, Leeward Islands

A low pressure system that has the potential to organize into a tropical storm prompted the issuance of Tropical Storm Warnings for Puerto Rico, the Virgin Islands and many of the Leeward Islands on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Potential Tropical Cyclone Nine was located at latitude 13.8°N and longitude 53.7°W which put it about 585 miles (940 km) east-southeast of the Leeward Islands.  It was moving toward the west at 23 m.p.h. (37 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 1007 mb.

Tropical Storm Warnings were issued for Puerto Rico, Culebra, Vieques, the U.S. Virgin Islands, Antigua, Barbuda, the British Virgin Islands, Montserrat, St. Kitts, Nevis, Guadeloupe, Martinique, St. Martin, Saba, St. Eustatius, and St. Maarten.

The circulation around Potential Tropical Cyclone Nine was very broad and it stretched from the southwest toward the northeast.  The stronger thunderstorms were occurring in the southwestern and northeastern ends of the circulation.  There were few thunderstorms or bands in the broad middle of the low pressure system.  Winds to tropical storm force extended out 200 miles (320 km) on the northern side of the circulation.  The winds in the southern half of the low pressure system were blowing at less than tropical storm force.

Potential Tropical Cyclone Nine will move through an environment favorable for intensification during the next two days.  It will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  The large broad circulation will contribute to a slow, gradual intensification.  If thunderstorms consolidate around a center of circulation and an inner core begins to form, then the system may be designated as a tropical storm.

Potential Tropical Cyclone Nine will move south of a subtropical high pressure system over the North Atlantic Ocean.  The high will steer the potential tropical storm toward the west-northwest during the next several days.  On its anticipated track Potential Tropical Cyclone Nine could approach the Leeward Islands on Wednesday morning.  It could approach the Virgin Islands and Puerto Rico by Wednesday night.  The large circulation means that Potential Tropical Nine will bring a prolonged period of gusty winds.  It could also drop heavy rain and cause flash floods on some islands.