As of the 10AM EST Public Advisory from the National Hurricane Center, Epsilon is a Category One hurricane with sustained winds of 75mph and a central pressure of 987 mb. The eye of the hurricane is 1220 miles west of the Azores and moving to the northeast at 14 mph.
Epsilon seems to be running along the last edge of the 'warm' water. One wouldn't expect sea surface temperatures (SSTs) this cool to support a hurricane, but Epsilon is squeezing every little bit of energy out of the ocean. This strengthening was seemingly enabled by the development of very healthy outflow, especially to the north of the storm (as is evident on the visible image). Convective banding has solidified and Epsilon's eye is now well defined with a diameter of about 25 nautical miles. While this strengthening is very impressive considering its location, cooler water ahead is expected to cause steady weakening tomorrow.
Epsilon is not the first Atlantic hurricane to form in December. In 1887, a weak hurricane traversed the Atlantic on December 7-12. In 1925 an unnamed hurricane formed on December 1 from an existing tropical storm and struck Florida. Ironically, it was only the second tropical storm of the entire year. From December 30, 1954, to January 6, 1955, Hurricane Alice 2 (yes, 2, it was the second Alice that season) crossed the Caribbean. December 12-24, 1984 saw Hurricane Lili cruise through the Atlantic, and in 1998, Hurricane Nicole hung around for part of the the first day of December.