An area of low pressure in the Atlantic is becoming better defined, according to satellite data from the National Hurricane Center.
Associated shower and thunderstorm activity continues to organize and a tropical depression could form by Wednesday
The disturbance could become Tropical Storm Bertha by Friday.
INTERACTIVE: Track tropical systems with our interactive map.
The low pressure system is about 1,600 miles east of the southern Windward Islands and was moving westward or west-northwest at 10 to 15 mph.
Meteorologists with the National Hurricane Center in Miami says there is a 70 percent chance of formation in the next 48 hours. Computer models posted by Weather Underground show the storm moving toward Puerto Rico and, eventually, the East Coast.
Depressions become tropical storms when sustained winds reach 39 mph and hurricanes when they reach 74 mph. The 2014 season has produced one named storm so far, Arthur, which developed into a hurricane before fizzling out near Nova Scotia, Canada.
Buoy reports in the Atlantic Ocean from SwellInfo.com predict waves of 9 feet in San Juan, Puerto Rico by the weekend with winds coming from the east-northeast. Those conditions would mean the storm has passed north of Puerto Rico and is moving toward Florida, Georgia and South Carolina.