Inversion Imminent

Tuesday, December 10, 2013 at 7:29 am

Very cold once again this morning.   Stable airmass is now firmly established overhead — that means the upper elevations will start to warm up close to normal as the week progresses while the valleys will become inverted with cold air trapped.  Urban haze is likely to develop as well.

We will be dry through the weekend with most of the storm energy passing to our north.  Ridge of high pressure is parking itself just off the west coast which is sending storms up and into British Columbia.  This will be the case through early next week.  There is a small chance that the southern extent of moisture could clip far northern Utah on Friday with a snow shower, but no accumulations are likely.

The good news is that the three major long range models we use — ECMWF, GFS, and GEM — are all showing retrogression of the ridge farther out into the Pacific late next week.  Potentially opening up the door for a storm system next Thursday or Friday (Dec 19-20).  It’s still a long way out so it’s not a forecast quite yet but at this point we are just looking for light at the end of the tunnel.

The past two storms have helped our snowpack for sure.  Here is the latest graphical view of the Snowbird snotel site (other snotel sites show similar numbers):



This year (green line) we are just below normal (about 80%) so far.  Over the next week, we should fall to about 70% before the next storm arrives.  Last year (red line) we had frequent small to medium storms through the whole month of December, then we hit January 1 and flatlined for almost a month, falling below average and never recovering.   The other thing to consider is that this measures SWE (snow water equivalent) — or how much water is in the snowpack.  We’ve had a few very low density snows recently.  The actual snow depth is probably a bit closer to average than the SWE.   Also consider that the cold air lately has allowed for plentiful snowmaking at resorts, so conditions really are quite good.

It’s not even winter yet! We’ll keep you updated on the potential for storms late next week!


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  • Gollum

    We hates’s nasty high pressures.

  • dug

    I’m all for looking for a silver lining, and skiing low snow beats not skiiing, but when you say this:

    “Also consider that the cold air lately has allowed for plentiful snowmaking at resorts, so conditions really are quite good.”

    I mean, no. They make snow on well traveled areas, groomers, corners, junctions. No resort is making snow on “the good stuff.”

    Doing my snow dance. You don’t want to know.

    • True, man made snow doesn’t really help my favorite kind of skiing either. 🙂

  • Laura

    Hi Evan, Thanks for all your hard work at WSF. I will be driving on 80 from the SF Bay Area out to PC on Sunday. I assume it will be clear sailing?

    • Yep, Laura. Right now it doesn’t look like there will be much trouble.

      • Laura


  • FYI, Meteorological winter is defined as the three coldest months throughout the winter, or December 1st through March 1st. Winter has officially arrived if you are a weather geek/Meteorologist

    • Yes, Scot, you are right about the difference between meteorological winter and astronomical winter. Semantics is not the point, the point is that it is still very early for people to be freaking about conditions.

      • I agree it is early to freak out about winter, there is no one that wants a big winter more than me! I want a big winter not only for the snow ski season like everyone else reading this but for my summer water ski season on Utah Lake which requires high water to ski in the protected slalom course locations.

    • trolls everywhere

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  • Everyone

    Dear Chap Stickman,

    Stop being such a nerd burger.



  • james

    At some point we all thought the last Two weeks of October would have no snow but we did get a storm…

  • Limp Dumpman

    All the models are calling for a huge storm at the end of next week

  • Copy Catman

    Dear Limp Dumpman,

    Stop stealing my names.

    Nevermind, imitation is the sincerest form of flattery.

  • Josh

    Thanks again for all you do!

    I was wondering if there was a good place for us novices to look at the ECMWF. I have found this website:, which gives a very nice look at the GFS, but haven’t found a site for the Euro.

    • Hey Josh, a lot of ECMWF parameters like precipitation are protected and only available if you pay for them or have connections. There are some good sights for comparing heights of major models. I suggest Meteocentre or San Jose State. It may not be as easy to read as the GFS, but at least you can get a general feel for how the models compare. Hope that helps.