The beginning of this week is rather boring with warm and mild weather. Should be great for getting outdoors and seeing what's left of the foliage, or maybe starting the process of winterizing your home. But weather-wise, let's just skip to Friday because until that point there is not much to talk about.

On Friday we will see a trough pushing into the Great Basin with rain developing primarily over Northern Utah.  This is an interesting system because the trough itself isn't particularly strong or deep.  What makes this system unique is that it will be picking up a cut-off low hundreds of miles off the California coast.  The trough will push the cut-off low into Sierra Nevada and across the Great Basin, directly into our area.  You can see this low being picked up by the trough to its north clearly in the below animation: 

Notice the blue circle being absorbed by the larger trough to its north at the beginning of the loop, then it pushing the whole thing into our area before moving out.  This low will add fuel to the system that would otherwise not be there.  Right now it looks like rain Friday afternoon into Friday night.  With snow levels starting high and gradually dropping.  Unfortunately, this low will also act to moderate the temperatures so it will not be a cold storm. Snow levels should be largely above 8000 feet for much of the event.  

Current model precip outputs for the next week look like this: 

You can see a healthy amount for northern Utah with lighter amounts for southern mountains.  This is significantly less than models were showing yesterday.  We are still 5 days away from the event, so it's no surprise there is still a wide range of possibilities.  This is reflected in the Ensemble forecasts for the Upper Cottonwoods: 

This range could translate to anywhere from 2-10" of wet snow for the highest elevations.  My best guess is that most of Northern Utah gets a good rain, while the peaks see a few inches of dense snow.  

If you're hoping for the snow to start flying in earnest, then you're probably out of luck.  It looks like this system is mostly a 'one and done' type of storm.  The jet retreats north and right now we may get brushed by a system early next week, but nothing significant.  Then, as we head toward the end of month, we may transition to a different pattern in which there is a persistent trough over the Eastern U.S. with ridging over the west.  

Personally, I'm of the mind that it can stay mostly dry until around Halloween, then it can snow all it wants.  So this forecast doesn't bother me too much.  I could use a couple more weeks of perfect mountain bike weather! 

Evan | OpenSnow