Change You Can Believe In

The stoke is high here at the Government Weather Control Office as we have finally been allowed to pull the "winter" lever for Utah and we are starting to see results.  

First, we got a skiff of snow overnight at the University of Utah.  Very exciting!

This snow is being produced by a closed low that is tracking to our south and is expected to be over western New Mexico by 1800 UTC (11 AM) this afternoon.  

Normally I would just say today is no game changer but any snow right now seems like a game changer.  For Alta, the HRRR generates little to no snow with this system today, but the GFS produces about 4" of low density fluff.  I'll go for 1–3" for Alta by 5 PM. Be grateful if we get that.  

But there's more coming.  Another weak upper-level trough moves into Utah tomorrow. Although it is weak, there's enough moisture and orographics in northwesterly flow that we continue to see periods of snow in the mountains tomorrow.

That snow tapers off tomorrow night.  

The HRRR, which is bearish on today and generates squat at Alta, is more enthused for tomorrow and generates about 6" of low-density snow before shutting things down by 8 PM.  

The GFS runs later than the HRRR, so the plot below only goes to 11 PM Friday, but it shows the GFS dripping out light snow through that time that ultimately adds up to 14" (including today). The snow to liquid ratios in the GFS are quite a bit higher than in the HRRR, so this reflects both the GFS being wetter, but also producing lower density snow.   

I'm inclined to go with an additional 5-10" of low density snow through 11 PM Friday on top of the 1-3" from today.  That's great, and it will help a lot, but expect a lot of bottom feeding through at least tomorrow morning.  Maybe by afternoon, if we come in on the high side of expectations, things will begin to feel smoother in areas that aren't heavily moguled.  

Beyond that, I currently like what I'm seeing in the models.  First, it looks to be cold.  Second, there are enough troughs coming through that we will probably get something additional next week.  The first opportunity is Saturday night through Monday as a trough digs into the US Southwest. 

This one might not be a direct hit for northern Utah, but we should get something.  Then the models are advertising the potential for another storm the middle of next week.

For Alta, the NAEFS is gnerating anywhere from about 1.25 to 5 inches of water through 0000 UTC 11 Jan with substantial snowfall amounts.  

I'm inclined to dismiss the higher amounts given the tendency of this downscaled product to be a bit excited, but expect improving conditions and increasing avalanche hazard in the coming week.  Monitor forecasts for timing and amounts as the details of trough movement and location still exhibit a range of possibilities.