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MIAMI (CBSMiami) - Tropical Storm Joaquin is expected to become a hurricane soon, though it probably won't threaten South Florida.

At 11 p.m., the center of the system was about 360 miles east-northeast of the northwestern Bahamas.

Maximum sustained winds had increased to 70 mph with higher gusts. Tropical-storm-force winds extend outward up to 125 miles, mainly to the east of the center.

Additional strengthening is expected during the next 48 hours, and Joaquin is forecast to become a hurricane later Tuesday night or Wednesday.

Tropical Storm Joaquin is moving toward the west near 5 mph and this general motion is expected to continue for the next couple of days.

A Hurricane Watch is in effect for the Central Bahamas.

Joaquin is expected to produce 4 to 8 inches of rain with isolated maximum amounts of 12 inches possible over San Salvador and Rum Cay through Thursday morning. Rainfall amounts of 3 to 5 inches are possible over the remainder of the Central Bahamas through Thursday morning, with 1 to 2 inches expected over the Northwest and Southeast Bahamas.