Finest of Margins

Friday, March 20, 2015 at 6:54 am

Saturday AM update:

Not much change from yesterday’s discussion (below).  Northern Utah is still on the periphery of good snowfall for Monday afternoon thru early Wednesday.  The best snowfall should occur to our north (Tetons), but mountain areas from about Provo northward should still get in on some of the action.  Right now I’d say accumulations will be modest unless something changes (e.g. trough sinking farther south).  Currently, ensembles are all over the place, suggesting anywhere from just a few inches to up to 20″.  I think 6-12″ for the Upper Cottonwoods is a good safe bet right now. The other piece of good news, however, is that temperatures will drop significantly during and immediately after this trough passage.  That should allow resorts to implement some snow-making where needed next week.

In other news, there are some rumblings going around of a stronger El Nino for next year.  I know many of you are probably saying, “Weren’t we supposed to have an El Nino this year?” The fact is that we did have an El Nino this year, just a very weak one.  El Nino generally brings below normal precipitation to the northwest (check) with above normal for southern California and the desert SW (not so much this year).  The reason we didn’t get the southern precip is likely that the weak El Nino didn’t quite strengthen the southern Jet enough to break through the ridiculously resilient ridge that has been fueled by +PDO all winter — essentially warm sea temps in the Eastern Pacific.  From what I’m reading, oceanographers and climatologists are saying that our chances at another (likely stronger) El Nino next year is somewhere between 40-80%.  Personally, I think it’s way too early for us to start conjecture about next year so I’d recommend not reading too much into these reports just yet.

Also, I think it’s worth pointing out that El Nino is NOT necessarily a good thing for northern Utah.  We went over this in the fall, but it’s worth re-mentioning.  History shows that in general, El Nino events are around seasonal average snowfall for all except far southern Utah.  The exception is extremely strong El Nino events such as 1982-83 in which we saw record snowfall.  So if you’re rooting for El Nino, ya better hope it’s a strong one!

You’ve heard me rant about the strong MJO a few times over the past two weeks. If you’d like further reading on the subject, and a bit about its influences on El Nino,  I’d check out this article shared with me by a reader:





Dry and warm this weekend with times of clouds.  A storm will affect Northern Utah late Monday thru Wednesday with mountain snowfall likely.


We are heading into the weekend continuing the regime of warmer-than-normal temperatures. A weak system will pass well to our north over the weekend, but could spread clouds and slightly cooler air into the region, especially in far northern Utah.

Attention continues to be on the trough for next week.  This was our “one hope” from the last discussion.  Models have generally converged on a middle ground as they so often do.  Right now the best precipitation looks to be just north of Utah.  With that said, the Wasatch and Uinta mountains should still see precipitation as both the GFS and EC bring enough energy down south to bring us somewhat decent mountain snowfall.  Here is the latest GFS qpf through middle of next week:


You can see by the map that the best precip should stay up in Western Wyoming (Jackson Hole/Targhee).  Still, I’d expect the Wasatch to see snow develop late Monday and continue off and on thru at least early Wednesday morning.  Snow levels should not be an issue for most resorts.

It’s a tough forecast right now because of how fine the margins are between little or no snow, and decent accumulations.  If the models trend just 50-100 miles farther south with the best energy, then the Wasatch could be looking at a fairly significant snow event.  However, if they trend 50-100 miles farther north, then we could get skunked.  There’s no question we need this storm, both for ski and hydrological purposes.  Needless to say, we’ll be watching this one closely in the models in the coming days…

Long range:

Ridging returns.  No matter what happens with the Monday-Wednesday system, it looks like it is one-and-done and we head back to ridging to close out the month of March.  There are still indications that an MJO-influenced change in the pattern could occur during the first week of April, but at this point I’m not getting my hopes up.



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28 thoughts on “Finest of Margins

  1. TJ

    Thanks for the update, appreciate all you do. Will be an exciting next few days (exciting being a relative term – I’ll take what I can get at this point). Arriving Wednesday night, will have to make a game-time decision on skiing Utah or Wyoming (or Colorado??)!

      1. TJ

        Thanks for the tip! Definitely keeping options open – including Targhee. Never been to either Targhee or JH – so it should be a blast if anybody gets snow.

  2. jim

    Evan, same question as yesterday…how do the ensembles look vis a vis the operational models. I see the gfs has trended back a little north since yesterday whereas the euro has stayed pretty much the same. Coming in on Sunday to ski the bird all next week so I putting a lot of hope on this trough.

    1. Wasatch Snow Forecast Post author

      EC and GFS ensemble means are fairly closely aligned now and seem to be very close to their respective operational runs. From here on out, I doubt there will be too much spread between ensemble mean and operational.

      1. jim

        as the trough moves through any chance of some lake effect banding with this system, based on past similar pattern?

  3. Mike Urban

    Wow. Thanks again for all your effort. I delayed another trip out for the third time this season. Looks like it might payoff. I have Tue-Fri to ride at Brighton. Then it’s pack it up for the season. I’m at “break-even” on my season pass right now….so lets hope for the best. Thanks again!

  4. Steve

    The latest 2 runs of GFS have it a bit farther north than I would like. How are other models? Also, thoughts on whether Snowbasin would do better if trends north?

      1. jim

        it appears that it has trended further north again. from the noaa website it’s not obvious what the qpf is, the resolution is not high. what do you have as qpf.

  5. jim

    Hey Evan, do you have an updated QPF from the 18z NAM. Only goes out to Tues. 6z but already looks decent.

  6. toknightsthoughts

    When do you think there will be reliable information regarding first week of April? Trying to decide on a trip to PC and need to figure out by middle of this coming week. I know it has been really bad but if the temps are better and if there is any chance or powder I will most likely make the trip.

    Your site is incredible and I really respect your input!

    1. Will it ever snow again in Tahoe?

      I’m no expert, but my take on the long rang models/guesses suggests that high pressure along the West Coast will still be the name of the game during the first few days of April. Some of the models suggest that Utah might still see some snow around April 1-4 from a storm that slides over the top of the high pressure. But I don’t see any signs in the current models to suggest that the high pressure over California will be replaced by a large trough during the first few days of April. The models are never very accurate this far out. But it seems like they are more accurate when they are predicting dry weather than when they are predicting wet weather. And right now, the models (as I read them), are fairly dry.

      My best guesses:

      Between April 1-4:

      50% chance of 0-3 inches
      30% chance of 3-6 inches
      20% chance of 6+ inches

        1. Will it ever snow again in Tahoe?

          Agree that outside of 7-10 days, it’s difficult to be too certain. Forecasts outside of seven days are inherently unreliable. Some interesting comments on that issue here:

          Some long-range tendency forecasts (which is a slightly different approach than the CPC’s official long-range deviation from climatology forecasts):

      1. Wasatch Snow Forecast Post author

        Well, technically the GFS goes out 16 days, but after 10 days it drops to a very low resolution and is basically useless. The ensemble mean is the tool to use beyond 10 days, it at least has some semblance of reliability. However, as mentioned in the discussion. My confidence in anything happening right now is very low.

  7. Steve

    What a shocker. NWS says Monday precip on track, but the stuff that was supposed to come over next couple of days after now going further north and east. Arrrgh!!! Calling for .2 to .25 inches precip. Bummer. Hope I’m misinterpeting all this. Sounds like dust on crust.

  8. Steve

    Evan, any thoughts on amount of snowfall? Also, I’m assuming cottonwoods will do better in NW flow. How about Snowbasin being further north?

    1. Wasatch Snow Forecast Post author

      updated discussion for ya, Steve. Snowbasin does have a bit of benefit of being farther north, but it lacks the elevation and orographic enhancement potential of Cottonwoods so I’d still expect them to do better.

  9. Will it ever snow again in Tahoe?

    6-12+ for Alta? That would be great! Unfortunately, I just don’t see the storm dropping that far south.

  10. jim

    Let”s hope this is another overachiever. Most of the snowfall this winter has been from storms that performed better than the models suggested.

  11. jim

    12z gfs shows slight trend south with trough from 6z. Should that translate to higher snowfall for cottonwoods or about the same? The NAM seems weak on precip totals compared to gfs.

  12. Mike

    Evan thanks for your forecast so much fun to read! Just got back from PCMR. Was there from March 15-20. Stayed near town lift. We had a great time but slope conditions were not great and were rapidly deteriorating with many runs closing while we were there. Still had fun on the slopes that were open. Last day even saw guy skiing in a speedo! If they don’t get snow soon I am no sure how much longer they can stay open. We went to Alta one day and it was beautiful and had plenty of snow and was great skiing! I hope they get some snow or at least gets cold enough to make snow so PCMR can stay open till end of season! Such a fun place!

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