Here She Comes

Tuesday, April 14, 2015 at 6:57 am

Tuesday 4:15PM Update:

As expected, Mother Nature went full BEAST MODE today with high winds, dust, and now rain and snow!  Snow is now falling in the Cottonwoods.  This will continue this evening with snow levels falling down to fall levels as temps plummet.  18z Model guidance came in more bullish than the 06z runs this morning.  I’ve decided to bump totals up further.  12-18″ for the Cottonwoods with perhaps even a bit more if everything comes together perfectly.

Wednesday is going to be EPIC.  Don’t miss it!




Strong cold front and spring system pushing into the area today (Tuesday).  Heavy precip with thunderstorms possible this afternoon.  Snow levels drop to valley floors.  Snow continues tonight into Wednesday in the Wasatch with significant-for-spring accumulations.  Wednesday POWDER!


Very windy today ahead of the cold front!


The cold front moves in from the northwest, heading southeast this afternoon.  Reaching the SLC area sometime just before your evening commute.  With lots of daytime heating and a favorable environment, convective thunderstorms are likely.  That means rumbles of thunder will accompany the wind, valley rain, and mountain snow as the front pushes through.  Today probably isn’t the best ski day, but if you’re on the mountain late this afternoon.  Be prepared for lightning holds on lifts around close if the front make it through on time.

Immediately behind the front, we’ll likely see a bit of a lull in the action early this evening.  This is the time when I get a lot of comments saying “That’s it! This storm is a dud!”.  Be patient, the main accumulating snows will occur tonight once the instability cold pool moves overhead.  Snow levels will also be at valley floors, so a couple inches down in SLC is possible.  There is even a possibility for lake enhancement of snow showers overnight downwind of the GSL.  On Wednesday, we could get some wrap around precip through the day but overall the activity should trend down.

As for forecasted totals, yesterday the 12z models blew up with QPF and that got reflected in the NOAA grid forecasts.  I had at least a dozen comments asking me if it was really possible that we could see 30″ of snow.   The subsequent 18z runs came back to earth so I don’t think those huge totals are going to occur.  Here is what the 12z NAM is currently showing:


About 7″ by midday Wednesday for the Upper Cottonwoods….  This model usually provides a good low end for us.  Next, let’s look at the higher resolution 4km NAM:


It is showing 17″ by midday Wednesday…  Now this model overdoes things at least 9 times out of 10.  So this should probably be considered the upper range, maybe even a few inches above the upper end of the range.  However, it does have the support of GFS ensemble mean:


Most ensembles paint anywhere from 10″ to 25″ of snow with a mean of around 18″ by Wednesday evening.  It should be noted, however, that the Euro model isn’t nearly as optimistic and only offers us 8-12″ of snow for the Upper Cottonwoods.

Finally, let’s look at a map.  Here is a NAM-WRF composite for snowfall:


Those areas of light orange over the western Uintas and the Cottonwoods region are encouraging.  It means 15″ or more of snowfall.

Okay, so that there was a lot of data to digest.  So what do I think that means for our snowfall chances?  I think the Upper Cottonwoods stand to see 8-14″ of snow, nudging up just a bit from yesterday with another day of consistent model runs.  I think the rest of the high Wasatch will be in the 5-10″ range.   If you were paying attention to the images above, then you probably know that there is a possibility for this storm to deliver more than forecasted, however, I’m going to keep this forecast conservative as things have rarely worked out for us since the start of 2015.  The BEST part of this storm compared to the one last week is timing.  Most of the snow that fell last Wednesday fell during open ski hours so it was getting tracked out almost instantly.  This storm, it almost all looks to fall in the window between closing on Tuesday and first chair on Wednesday.  WEDNESDAY is absolutely the day to get after it!  First chair!

For the most part, high pressure takes control after this storm with few chances for snowfall in the next 7-10 days.


P.S.  I checked this after I had already written today’s post, but it is the HRRR simulated radar.  Check out the front firing up over the Wasatch Front this afternoon/evening:



Weather geeks love good thunderstorms!  Let’s hope for some radical thundersnow this evening!

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  • um. what about the OGDEN VALLEY?

    • 5-10″ on the high mountains around OV, but probably just a 1-3″ inches in the valley itself.

  • Cory

    Love thunderstorms!

  • Nate

    praise the norse snow gods!

  • Anth

    Do you think this storm is going to have a significant impact on the La Sal’s?

  • Brandon

    I am in cottonwood anyone give me a lift to Brighton I just took my tires off ?