Tropical Depression Four formed south of Cuba on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Depression Four was located at latitude 21.4°N and longitude 79.7°W which put the center about 75 miles (120 km) south of Caibarien, Cuba and about 260 miles (415 km) south-southeast of Key West, Florida. Tropical Depression Four was moving toward the west-northwest at 17 m.p.h. (28 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 1010 mb.
A Tropical Storm Warning was in effect for the portion of the coast from East Cape Sable to Boca Grande, Florida. A Tropical Storm Warning was in effect for the Dry Tortugas.
A Tropical Storm Watch was in effect for the Florida Keys from south of Card Sound Bridge. A Tropical Storm Watch was in effect for the portion of the coast from East Cape Sable to Card Sound Bridge, Florida. A Tropical Storm Watch was in effect for the portion of the coast from Boca Grande to the mouth of the Suwannee River, Florida.
A distinct low level center of circulation developed over the Caribbean Sea south of Cuba in a tropical wave previously designated as Potential Tropical Cyclone Four, and the U.S. National Hurricane Center designated the system as Tropical Depression Four. More thunderstorms formed near the center of Tropical Depression Four on Friday night. Thunderstorms also developed in bands revolving around the center of Tropical Depression Four. Storms near the center of circulation began to generate upper level divergence that pumped mass away from the tropical depression.
Tropical Depression Four will move through an environment favorable for the formation of a tropical cyclone during the next 24 hours. Tropical Depression Four will move over water where the Sea Surface Temperatures are near 30°C. It will move under the southeastern part of an upper level ridge over the southeastern U.S. The ridge will produce northeasterly winds that will blow toward the top of the tropical depression. The winds in the lower levels of the atmosphere will also blow from the east and there will be little vertical wind shear. Tropical Depression Four is likely to intensify slowly as long as the center of the depression is near Cuba. The tropical depression is likely to intensify more rapidly when it reaches the Gulf of Mexico.
Tropical Depression Four will moving around the southwestern part of a high pressure system over the western Atlantic Ocean. The high pressure system will steer Tropical Depression Four toward the west-northwest during the next 24 hours. On its anticipated track, Tropical Depression Four will move across western Cuba and into the Gulf of Mexico. The tropical depression is likely to move toward the north during the weekend when it reaches the western end of the high pressure system.
Tropical Depression Four is likely to bring gusty winds and locally heavy rain to Florida during the weekend. Heavy rain could cause widespread flooding. Tropical Depression Four could also cause a storm surge along the west coast of Florida.
A Storm Surge Watch is in effect for the portion of the coast from Bonita Beach to the Mouth of the Suwannee River, Florida. The Storm Surge Watch includes Tampa Bay and Charlotte Harbor.