One, of immediate interest to the islands of the eastern Caribbean, is expected to approach the Lesser Antilles on Saturday. From there models aim it toward Puerto Rico, Hispaniola and eastern Cuba.
Whether it could threaten the U.S. coast, it's too early to say. For now it's moving in this general direction.
At 8 a.m. on Friday, the large tropical wave was about 900 miles east of the Lesser Antilles, moving west at 20 mph.
Saying conditions are favorable for strengthening, the National Hurricane Center gave it a 40 percent chance of developing over the next two days. It already is showing signs of organization, forecasters said.
The other wave was about midway between the coast of Africa and the Cape Verdes Islands, moving northwest at 10 to 15 mph. The hurricane center gave it a 50 percent chance of developing over the next two days.
At 11 a.m. on Friday, TD-8 was about 315 miles east of Belize City and near the Honduras-Nicaragua border. It was moving west at 10 mph with sustained winds of 35 mph. Forecast to briefly strengthen into a tropical storm, it could produce up to 8 inches of rain over Central America.
The next three named storms will be Harvey, Irene and Jose.