As usual, I was off on my prediction. The temp on the summit only dipped to 23F last night. If indeed it dropped to the teens in the valleys, then there was an inversion where the temps on the summit were warmer than the valleys. This of course had nothing to do with riming as I was forgetting my basics. Passing clouds form the rime ice on the summit and frost is a totally different process. Bill, of course knows this, so I probably gave him a good chortle. Not sure where to look to see if they had any clouds or riming last night. Looked at the 24 hour stats but cloud cover and riming isn't listed. Would it be in the Metar? Also, is there an archive of the ARVTP? This would show the inversion assuming all the stations were on line and there was indeed an inversion. Bill?
Maybe the observers could help out on this one. Was there any riming or frost or anything on those instruments last night or this morning?