I did 16 today and actually felt reasonably good, though I was tired before I'd even finished 13. My mood was about 1000% better than it was for my last long run, and I even threw in a little bit of a kick for the last mile. It was just about 68° and this is the weather the DeSoto arm coolers were made for - they totally kept it from being uncomfortably hot.
I swear, if I'd remembered how hard it was to ramp up mileage past 14, I'd never have let myself get so out of shape. 
BikeChick, good luck at Disney tomorrow!! (Isn't someone else from here running, too??)
Speed comes from what you put behind you. - Judi Ketteler