An area of tropical downpours is currently swirling over the Leeward Islands, where the Caribbean meets the western Atlantic Ocean. These downpours are associated with a tropical wave that will move northwest over the next few days.
Although the disturbance will produce heavy downpours over over Puerto Rico and Hispaniola, it is not expected to strengthen due to the strong upper level wind shear that is in place over the Caribbean. Wind shear is the term used to describe the change in wind speed and direction from the surface to higher altitudes above the ground. When high, or strong wind shear is present in the tropics, the shear can rip apart the structure of the storm system, weakening it in the process.
Although strong wind shear is expected to keep the system from developing into a tropical depression or a tropical storm, the disturbance will likely bring heavy rain and gusty winds to the Bahamas as well as southeast Florida by the end of the week.
Below is additional information from the National Hurricane Center.
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Sun Jul 28 2019
For the North Atlantic…Caribbean Sea and the Gulf of Mexico:
1. A persistent area of cloudiness and thunderstorms located over the
eastern Caribbean Sea is associated with a tropical wave. This
disturbance is expected to move west-northwestward to northwestward
across the north-central Caribbean Sea during the next few days,
producing locally heavy rainfall and possibly some flooding across
portions of the Lesser Antilles, Puerto Rico and Hispaniola. Little
development of the disturbance, however, is likely during this time
as upper-level winds are becoming less conducive. The system is
forecast to move near or over the Straits of Florida or the Bahamas
by the end of the week where environmental conditions could be a
little more conducive for development.
* Formation chance through 48 hours…low…10 percent.
* Formation chance through 5 days…low…20 percent.