Northernmost and southernmost hurricanes in the Northern Hemisphere?

I was just browsing information on Hurricane Isabel, which I had the thrill of confronting in 2003 (seriously--check out a href="http://www.jesusfreak.com/isabel.asp" rel="nofollow"http://www.jesusfreak.com/isabel.asp/a ) and got to wondering, what has been the farthest north and farthest south hurricanes have gone in the Northern Hemisphere? I'm no meteorology expert, but isn't it theoretically impossible for a hurricane to cross the equator?