Saturday, March 17, 2012

Winter to Return

Some temperatures this morning: 59F at the University of Utah, 48F at Kimball Junction, 44F in Park City, 39F at the Base of Alta.

Snow and rain were spitting in the mountains last night.  Alta-Collins had .09" of SWE and an inch (maybe a half rounded up) of snow since midnight at a temperature of 32–33F.  South winds will be on the increase today.  For some sick and demented reason, I'm looking forward to heading out shortly to make some turns.  I'll be wearing a hard shell.

There's not much change to report in the model forecasts which still call for winter to return tonight as cold air penetrates into western Utah and heavy precipitation sets up along an axis very near if not over the Wasatch and other high mountain areas that run down the center of the state.

There may be a bit of a break for part of the day on Sunday, but periods of snow are likely through Monday. The overnight NAM forecast calls for 1.22" of water at Alta and about 18" of snow for the entire period.  We'll do better if the precip band on Sunday night can setup in the right place and the orographics can get going later in the event.  Worse if those things don't come together.

I've been grumbling about the complexities of the forecast the past few days and continue to do so.  This is a complex pattern.  I think we're going to see a good dump in the aggregate, but specific aspects of the timing, location, and intensity of precipitation remain difficult to determine.   I've learned in patterns like these that the best plan is to plan to ski.  

Addendum 9:10 am

There's been persistent radar echos in the area downstream of Mount Timpanogos and Lone Peak on and off for most of the night.  It hasn't added up to much, but as shown in the picture below, one can see a firm, hard cloud base to the west and southwest of Lone Peak, with precipitation falling out downstream.  This is happening, in all likelihood, due to strong rising motion as the strong south-southwesterly flow impinges on the high topography.  Showers of this type will likely continue at times during the day today.


  1. You liking the NAM or GFS?

  2. In this case, I think they are telling a fairly similar story with regards to the evolution of the storm on the large scale. When that happens, I typically lean toward the NAM due to it's higher resolution and better precipitation physics. That being said, this is a case with a wide range of possibilities. What is supposed to fall tonight will come from a frontal and precipitation system that will intensify over central Utah and we haven't seen the "whites of it's eyes yet." I'm hoping it develops as anticipated by the models.