It's a Trof!

 

Although it's only a brief flirtation with the storm track, we will see a trough passage tonight and tomorrow, one that will bring a bit of snow for skiing and some wind to clean out the smog that's occupied the valley for far too long.

Tonight, the upper-level trough rolls over the large-scale ridge that is presently off the Pacific coasts and drops into Utah.  At 1200 UTC, the upper-level trough axis is nearly over Salt Lake City.  

For the central Wasatch, expect periods of snow to develop tonight a bit before midnight and continue into tomorrow morning.   There will also be some snow at times in the Salt Lake Valley.  NWS forecasts are calling for a trace to 2 inches of snow in the northern valleys.  

We might do a bit better than that on the east bench, but this doesn't look like a big event for accumulation.  However, we haven't seen snow around here in a while, so heads up for the morning commute.  

For the central Wasatch, our GFS-derived Little Cottonwood forecast is putting out a miserly 0.32" of water and 5" of snow through Friday afternoon.  

This is very close to the mean from the Short Range Ensemble Forecast System (SREF).  And, if you look at the accuulated snow plume, 19 of the 26 members are between about 5 and 7 inches.  Three are under five and 4 are above 8, but most are locked in around those dust-on-curst amounts.

Thus, I like 4-8 inches for Alta-Collins with most of that falling before 1500 UTC (8 AM MST) tomorrow morning with a few snow showers beyond that.  It's not much, but beggars can't be choosers.  

As the trough moves southward, it amplifies and closes off over southern Utah and Northern Nevada Arizona later tomorrow.  

This results in easterly flow across the Wasatch Crest, with downslope winds (known locally as Canyon winds) possible tomorrow night and Saturday morning.  Right now, this doesn't look like an extreme event, but monitor forecasts.  At least it should ensure that if the trough passage itself doesn't crack the inversion and mix out the pollution, the enhanced flow should the job.  

Sadly, this is not the pattern change we've been looking for.  Jedi mind tricks sadly won't change that.  The pattern through the next work week continues to advertise below average snowfall with are best hope being troughs that roll through the ridge.  After that we will see.  It's time to start burning skis again.