Hell is about to freeze over

Photo: good-times.webshots.com

In an earlier post, I mentioned that there aren't alot of days when the 700 mb temperature is below -20C and that the GFS was going for something like -21C this week.  I also wondered if that would verify, thinking that it would probably not end up being that cold.

Well, the latest GFS runs are instead calling for it to be even colder.  The latest GFS 700-mb temperature forecast for 15Z Wednesday is -25.3C.  Trevor has examined the KSLC RAOBS for 1956-2010 and has found that the coldest November 700-mb temperature observed in that period is -22.6C.  Further, there have only been 14 soundings (out of 40,246) with a 700-mb temperature below -25C during the entire record.  The last day we were below -25C was on 30 December 1990 when the 700-mb temperature was -27.2C.

Let's convert to American units to put this into perspective.  -25.3C = -13.5F.  That is a seriously cold day of skiing in the mountains.  Well mixed, that's 17F in the valley.  Cold.  Bloody cold.