PWL or Not PWL, That Is the Question

The weekend storm was a good one for October with the Collins gauge recording about 2.66"of water and 25" of snow if my interpretation of the data is correct. I didn't try to ski yesterday, but noticed a well-formed conga line heading up Corkscrew each time I took a look at the Alta web cams.  

The question now is whether or not this will continue, building up a stable snowpack for the coming ski season, or whether or not the ridge will return, resulting in the development of a persistent weak layer (PWL) on north aspects.

Forecasts for the next week at least suggest we will have some chances to add to the snowpack.  The first is tonight and early tomorrow when a weak upper-level trough and cold front move through.  

The next is Wednesday and Wednesday night when another upper-level trough and cold front are forecast to move through.  This one is a bit stronger.  

From these two storms, the GFS generates about 0.9" of water and 13" of snow. This is roughly inline with the mean of the downscaled NAEFS which, after deducting the light amounts forecast for last night, comes in at around those totals for the mean, with most of the members between 0.5 and 1.5 inches of water equivalent for the two storms. 

My view is that would be another good add for the week and we shouldn't complain.  Whether or not a persistent weak layer becomes an issue will depend strongly on the weather around and following, gulp, Halloween.  The model forecasts for then divergent enough that I'm not even going to speculate.  The GFS brings a weak trough through Utah the western US this weekend that doesn't do much for us and moves downstream into West Texas by Halloween afternoon. 

The ECMWF has different ideas and amplifies that trough and parks it over California.  

My view is we should enjoy this week's snow and worry about the PWL potential another day.