Mother Nature refuses to let us rest... Another strong storm is approaching.  

It's a very interesting pattern that we've got setup.... Firstly, we have another very cold system dropping down the west coast from western Canada and the arctic.  Seattle has once again been receiving snowfall over the past 24-hours.  This is their snowiest month on record since 1969.  That means there is lots of cold air associated with this system, as has been the case in previous systems.  However, this time it is interacting with even more sub-tropical moisture from the southwest and pulling up and AR (atmospheric river).  That moisture is going to raise snow levels in the Sierra and eventually Utah as well prior to the arrival of the cold core of the system.  It's also going to bring big totals of both snow and rain -- depending on elevation.  

Today (Tuesday) we continue to be clear.  We already have a few more high clouds than yesterday (which was perfectly clear bluebird).  Here is sunrise at Alta: 

Clouds will likely continue to increase throughout the day today.  

The first part of the storm moves in tomorrow (Wednesday).  Snow should start to develop in the high elevations by late afternoon or evening.  Snow should continue off and on thru Thursday in a moist westerly/southwesterly flow.  Snow levels will rise off the valley floors up to 6k feet or so on Wednesday night and Thursday.  Snow in the mountains will be of the denser variety thru Thursday. 

Colder air arrives for Thursday night as the core of the system pushes thru, we should see snow continue into Friday morning.  Friday could be a great powder day.  

Additional impulses could keep snow showers going into the weekend as the trough crosses the area and heads east.  

As for snowfall totals.... really hard to say, the Euro gives us a good amount of snow but nothing too crazy.  The latest GFS is going off the walls.... look at total precip by the end of the weekend: 

Those are some colors up there in the Cottonwoods that we rarely see in a 5-day window.  When converted to snowfall: 

A metric buttload of snowfall!  I'm not sure I'm ready to bite off on this quite yet, but the GFS ensemble average is mighty high: 

That's an average of 4" of liquid for the Upper Cottonwoods.  

Because the Euro is not as robust in its totals, I think I'm going to be more conservative and expect 1-3" of liquid in the mountains from this storm.  That can roughly translate to 1 to 3 feet of snow, with the highest amounts likely in the high elevations of the Cottonwoods.  If the latest GFS is on to something, maybe there is a chance for more but there is just too much uncertainty right now.  

It will be getting much colder for this weekend so be prepared for chilly conditions on the mountain! 

We generally trend drier as the high pressure that's been parked in the Pacific nudges closer to the coast.  The GFS has us going almost completely dry with just cold air in place.  The Euro has us hit by a weaker system around the 20-21st timeframe.  Either way, we should stay relatively cold as we are on the backside of the ridge where the air is dropping down from Canada.  

Evan | OpenSnow

P.S.  Stoke is high right now but the lack of confidence in the details of this system are keeping it from approaching 'extreme' levels.