A Visit From the Pacific Jet

There's a storm coming in tonight but the big story for the mountains isn't snow, but wind.

As shown by the GFS jet-stream level forecast for 1800 UTC (1200 MDT) tomorrow, the Pacific jet will be penetrating across a low-amplitude off the Pacific coast and southeastward into Utah.  Jet stream level wind speeds at that time exceed 60 meters per second (120 knots).  

I used to fly a decent amount between Salt Lake City and Denver, and in patterns like this I used to plan on there being no drink service and the fasten seatbelt sign being on the entire flight.  It's a recipe for mountain-induced gravity waves and turbulence.  

The time-height section for Salt Lake City shows a lot of black flags at upper levels from 0000 UTC Tuesday (6 PM MDT Monday) to 1200 UTC Thursday (6 AM MDT Thursday).  Winds at 650 mb, roughly the altitude of Mt. Baldy and other 11,000 foot peaks, maximize from around 0600 to 1200 UTC Tuesday (Midnight to 6 AM MDT Tuesday) as a cold front pushes through the area. 

Our Little Cottonwood forecast product has gusts on Mt. Baldy reaching over 70 mph overnight tonight and remaining above 50 mph through 11 AM MDT Wednesday (see center left panel).  I won't be surprised if they go higher than that.  Typically this product underestimates the peak gusts.  

On the plus side, there will be some snow.  The GFS is putting out 0.68" of water and about 6 inches of snow for Alta-Collins through noon MDT Tuesday.  This is, however, on the high end of the SREF forecasts, which max out at 6 inches.  

Bottom line: Expect an angry storm with 3-7 inches of snow that may end up in Wyoming.