Saturdays Weather and Snow Obs

It was a beautiful day today if you were above the stratus clouds that were hanging around in some areas and tonguing up Little Cottonwood Canyon.  Upper White Pine on a sunny day with a deep snowpack is as pretty as it gets.  

However, in the lower canyon and in Little Cottonwood, stratus lurked.  

Such clouds can develop in mountain valleys and canyons when a ridge builds in and produces an elevated inversion or stable layer that caps moisture at low levels.  Indeed that was the case today with a stable layer evident in the morning (5 AM) Salt lake City sounding between about 725 and 675 mb, which is just below crest level.  

This stable layer likely lowered some by mid morning.  In fact, during our tour we ate lunch right at the top of the cloud layer.  You could feel the temperature cool when the clouds moved in and then warm when they retreated.  

In addition, there was just enough humidity in the air to enable ice crystal growth.  Look carefully in the photo below and you can see the sparkling ice crystals. 

Here are a few of my dendritic friends on my glove. 

Meanwhile, on the Earth's surface, we have the best snowpack in a decade.  I have a friend visiting from Innsbruck and pulled out my 3-meter probe to impress him.  The bottom was not hit.  That's 120 inches in US units and of course the snow depth was deeper than that.  

In the short-range forecast, a cold trough is forecast to move southward right along the Nevada–Utah border tomorrow and tomorrow night.  It will bring a few snow showers to the Wasatch tomorrow, although accumulations are likely to be modest.  The 18Z GFS is putting out just under 4" of low density snow for Alta-Collins by Sunday evening and the normally exuberant HRRR a miserly inch.  Call it 2 to 4, hope for more, and pray we don't settle for less.  

There is, however, some potential of easterly flow including downslope winds on Sunday night and Monday morning.  Note the northeasterly winds in the GFS forecast over northern Utah at 0900 UTC Monday morning.  

Right now this looks like an enhanced but not severe easterly wind scenario, but keep an eye on forecasts if you live in canyon or downslope wind prone areas.  Napoleon and meteorologists know all too well that nothing good comes from the east.