Déjà Vu All Over Again

I had a mild bike ride to the office this morning for November 11 and the forecast high for this afternoon is 65 for KSLC. 

Tomorrow will be different. 

However, it is a bit of a case of déjà vu all over again as it is a system that reminds me of the others we have had so far this fall with the strongest part of the trough and the so called "dynamics" moving to our south.  We get a frontal passage and some precipitation, but looking at the models, the system is just not put together great to give us a really big dump. 

Below is the GFS forecast valid 1200 UTC 12 November (6 AM MST Tuesday).  The strongest part of the 500-mb trough is basically over Northern Arizona and southern Utah and passing to our south.  The surface front is pretty much over Salt Lake City, but the 700-mb temperature contrast with it is somewhat diffuse and the precipitation with the front scattered and not all that organized.  

The GFS time height section shows very dry air ahead of the front and then a period of about 6-hours with deep moisture as the front moves through.  We do get into northwesterly post-frontal flow Tuesday night, but it is fairly dry at low levels (below 800-mb).  This is not the kind of forecast that causes my heart to flutter. 

The latest models are calling for a small storm at Alta.  Through late Tuesday the HRRR generates 0.25" of water and 3.5" of snow and the GFS  0.37" of water and 5" of snow.  The experimental RRFS has a remarkable amount of spread with one member producing essentially a trace and another up at 10".  

I'm not sure what to make of that, but I view that 10" as something close to the upper limit of what I'd expect under the best of circumstances, with a significant boost from lake-effect interactions with the terrain behind the trough.  

Finally, the Utah Snow Ensemble is generally in the under 12" range with means from the two ensemble systems at about 4" and 6".  Yes, I know there's more snow after this system in this forecast but I'm not going to address that here.  Whatever you do, don't be biased by the highest members! (See Anchoring Bias and Ensembles for why). 

It is what it is, another modest system that will add a bit more to our November snowpack.  I'm thinking 5-10" for Alta Collins. Although it is clear that the ensembles are saying the range of possible outcomes for this event is pretty big, there isn't much here to get me thinking about more than a foot.  That said, none of these models are particularly good at dealing with the post-frontal northwesterly orographic snowfall enhancement in the Cottonwoods.  Then again, they also aren't advertising a great environment for that.