A low pressure system over the central Caribbean Sea prompted the issuance of Tropical Storm Watches for Jamaica and Grand Cayman on Sunday afternoon. The National Hurricane Center designated the low pressure system as Potential Tropical Cyclone Fifteen. At 5:00 p.m. EDT on Sunday the center of Potential Tropical Tropical Cyclone Fifteen was located at latitude 15.7°N and longitude 73.6°W which put it about 265 miles (425 km) southeast of Kingston, Jamaica. It was moving toward the west-northwest at 10 m.p.h. (16 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 1005 mb.
Tropical Storm Watches were issued for Jamaica and Grand Cayman.
Reconnaissance planes from the U.S. Air Force Reserve and NOAA found winds to tropical storm force in the northern side of a low pressure system over the central Caribbean Sea on Sunday. Based on data collected by the planes, the National Hurricane Center designated the low pressure system as Potential Tropical Cyclone Fifteen. There was a large counterclockwise rotation around the low pressure system. Several small counterclockwise swirls were revolving around the larger low pressure system. Winds to tropical storm force extended out 115 miles (185 km) in the northern side of Potential Tropical Cyclone Fifteen. The winds in the southern half of the low pressure system were blowing at less than tropical storm force.
Potential Tropical Cyclone Fifteen will move through an environment favorable for intensification during the next 36 hours. It will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the northwestern part of an upper level ridge over the eastern two thirds of the Caribbean Sea. The upper level ridge will produce southwesterly winds that will blow toward the top of Potential Tropical Cyclone Fifteen. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Potential Tropical Cyclone Fifteen will be designated as a tropical storm if more thunderstorms form closer to the center of circulation. It could eventually strengthen to a hurricane later this week.
Potential Tropical Cyclone Fifteen will move south of a high pressure system over the western Atlantic Ocean. The high pressure system will steer Potential Tropical Cyclone Fifteen toward the west-northwest during the next 36 hours. On its anticipated track, the center of Potential Tropical Cyclone Fifteen will pass south of Jamaica on Monday. It will bring gusty winds and locally heavy rain to Jamaica. Heavy rain could cause flash floods in some locations.