Friday, September 27, 2019

Epic Early Season Snow for Some

Source: NWS.  Downloaded 5:42 MDT Friday 27 September
A potentially historic early season snowstorm is expected to affect Montana over the next few days as an unusually deep early season trough develops over the western United States combines with easterly upslope flow and moisture of Pacific and Gulf of Mexico origins.  Call it a perfect storm if you must. 

The latest National Weather Service forecast calls for 24-30 inches at Marias Pass in Glacier National Park, but higher totals, exceeding 36 inches, in some mountain locations.

Downscaled SREF forecasts show mean snowfall totals for the period exceeding 36 inches in higher elevations of Glacier National Park where every SREF member is generating more than 24 inches of snow.  

The event will feature strong surface winds, which will make driving conditions even in the plains very difficult. 

Meanwhile, in the Wasatch, we're looking at a warm, south wind period Saturday with a cold frontal passage at some point over the weekend.  Phasing between the moisture and the cold air just never seems to come together right for this one.  Most of the latest SREF members generate less than an inch of snowfall for Alta Collins, although there are a few that go for more. 

It's not out of the realm of possibility we do better than that, but I would keep expectations low.  Low expectations are the key to a happy life.  It's too early for snow anyway.  


  1. " It's too early for snow anyway." Amen!

  2. It looks like the warm sector might be fairly active, as the closed low over Arizona is leaving behind a lot of low level moisture that is ready to be advected northward into Utah (mostly below the 700-mb level). I noticed a good deal of fog over Arizona on the high-res satelllite images this morning, as an illustration of this.

    1. The SPC's 1730z day 2 outlook mentions there could be some severe winds in the northern Utah/Wyoming area tomorrow. Curious to see if we get an upgrade to marginal in the day 1 outlooks.

  3. As long as this doesn't turn into two years ago where Montana/Wyoming got pounded while Utah sat out of the game on the bench, I am totally ok with this.