Tropical waves in the Atlantic Ocean form from disturbances which drift off the continent of Africa onto the Atlantic Ocean. These are generated or enhanced by the African Easterly Jet. The clockwise circulation of the large transoceanic high-pressure cell or anticyclone centered near the Azores islands impels easterly waves away from the coastal areas of Africa to North America. About 60% of Atlantic tropical cyclones originally form from tropical waves, while about 85% of intense Atlantic hurricanes (Category 3 and greater) form from tropical waves.