 While passing to the south of Bermuda , the subtropical storm maintained winds of 70 mph ( 110 km / h ) , with wind gusts on the island surpassing 100 mph ( 160 km / h ) . After becoming dissociated from the Westerlies , the system turned northward , and began to develop convection over the center . In addition , the frontal characteristics of the subtropical storm continually weakened . On October 13 , based on an Advanced Microwave Sounding Unit observation that stated that a warm core was present throughout the system , the National Hurricane Center designated the system as a tropical storm , and gave it the name Karen . At this point , Karen was located 200 miles ( 320 km ) north of Bermuda . Karen slowly strengthened over the warm waters of the Gulf Stream , and the storm intensified to a hurricane later on October 13 . Convection continued to develop , and organized into a ring around the eye as Karen reached its peak intensity of 80 mph ( 130 km / h ) on October 14 while located about 400 miles ( 640 km ) south of Halifax , Nova Scotia . 
