 On September 20 , <unk> imagery indicated an area of convection becoming concentrated while well south of the Azores . It is possible that a mid to upper @-@ level cyclonic circulation interacted with the northern portion of a tropical wave . By the following day , satellite imagery noted a well @-@ defined low @-@ level circulation and thus , Tropical Depression Five while centered about 633 miles ( 1 @,@ 019 km ) south of the Azores . The depression tracked northwestward and satellite imagery began to indicate banding features . As a result , the depression was upgraded to Tropical Storm Charley on September 22 . An eye developed as Charley tracked north @-@ northwestward , and it became a hurricane on September 23 . Further strengthening occurred , and by late on September 24 , Charley peaked as a 110 mph ( 175 km / h ) Category 2 hurricane . 
