Hot off the presses...

"Like the ocean, the atmosphere also has waves. Large-scale
atmospheric waves form over Africa during the African summer monsoon
season, track east to west, and emerge over the Atlantic Ocean near
the Cape Verde Islands, where they often serve as the nucleus for a
powerful Cape Verdes-type hurricane. Well, the African Easterly Wave
Factory is exceptionally busy right now, and there are three very
impressive looking waves with plenty of spin lined up across the
continent.

http://www.swsports.org/images/africa_sat_aug30.jpg

The western-most wave, just coming off the coast of Africa today, is
particularly impressive. This system has a very large circulation with
plenty of spin, and is already developing some concentrated heavy
thunderstorms over the waters south of the Cape Verde Islands. This
morning's QuikSCAT pass saw winds of 50 mph near the heaviest
thunderstorms. Wind shear is a moderate 10-20 knots over the storm,
and is expected to remain in the low to moderate range the next few
days. NHC has given this system a medium (20%-50%) chance of
developing into a tropical depression by Saturday. The models have
been very aggressive developing this system over the past few days,
and chances are good that this system will become a large and powerful
Cape Verdes-type hurricane next week. It is too early to speculate
whether this storm might end up recurving out to sea or not.

The other two waves lined up behind the wave moving off the coast are
also likely to be a threat to develop once they move offshore Africa
next week. The long-range GFS model develops all three of these waves.