Thursday Storm Must Come Through

The snow accumulation season has gotten off to a slow start.  In my view, the Thursday storm must come through to get the Nordic season off life support and help more with the upper-elevation snowpack.  The time has come.  Let winter begin.  

The forecasts are optimistic.  The GFS has a productive, slow moving frontal system moving across northern Utah on Thursday.  The forecast below is for 5 PM Thursday afternoon.  Temperatures are low enough that even if the storm starts out as rain at the airport, it should be cold enough to snow at Mountain Dell and the lower trailheads in the Cottonwoods and Mill Creek.

Water and snowfall totals for Alta from todays 6Z initialized GFS for 8 AM Thursday through 4 PM Friday are .91 and 12.8 inches, respectively.  The NAM is a bit less enthusiastic with 0.54 and 7.6 inches, respectively.  

The downscaled SREF is unusually excited, with all but 2 members producing 12" or more (including the light snow prior to Thursday's main event), with a maximum of about 28 inches. The mean is about 17 inches.  Deducting the mean from the weaker pre-Thursday events and you have a mean storm total of about 15 inches.  

One of the things I like about the storm is the frontal passage Thursday afternoon and evening looks to be quite productive.  That will be good for all elevations, and we need snow everywhere right now.  

The downscaling we do sometimes overdoes the snowfall at upper elevations in those periods, so perhaps the higher SREF members are overly optimistic.  I suspect to get to 2 feet or so at Alta we will need the post-frontal northwesterlies to come through big time.    

Personally, I like the 8-14" forecast advertised this morning in the Utah Avalanche Center advisory.  That seems like a good number for the upper Cottonwoods.  This will be a significant event for the valleys as well and should help with Nordic skiing at Mountain Dell.