 As it began to execute a turn towards the north under the influence of an upper-level trough to its west, a central dense overcast was noted on satellite imagery.Following a series of intensity estimates, Rafael was upgraded to a hurricane around 0600 UTC on October 15, while positioned about 650 mi (1045 km) south of Bermuda, although this intensity was speculated upon until later that afternoon following a hurricane hunters flight into the system.As Rafael moved northward, it continued to intensify rapidly in spite of moderate wind shear.