Difficult Forecast

Saturday, November 19, 2016 at 7:01 am

Summary:

A complicated storm will bring valley rain and mountain snow to the region on Monday.  Additional weak storms possible next week. A chance for stronger storms after Thanksgiving.

Details:

Storm #1  Generally quiet today and Sunday, before an interesting storm moves in for Monday.  This is the splitting storm we’ve been talking about for the last several days.  It is still splitting dramatically, but now, the southern split has been trending much farther north with its track as it ejects east.  This is going to give us a good shot at mountain snowfall on Monday.  If you always think, “Boy, it always seems like models trend downward as the storm gets closer.” This is an example of the exact opposite. Two days ago models virtually brought us nothing, now they are bringing a chance for decent accumulations to the mountains.

It does appear there will be a band of heavier precipitation.  The amount specific locations will receive could vary dramatically depending on where this band of heaviest precipitation forms on Monday.  The NAM has been moving this band farther North and west with each model run, there is the rough positioning of the band over the past 24 hours according the the NAM model:

1119_utah

For the Wasatch, it was yesterday’s 12z and 18z model runs that were the most optimistic.  The 00z and 06z this morning came back down again as the best precipitation now stays mostly west of us.  On the other hand, the GFS keeps the best precipitation over the central Wasatch in its most recent run.  The Euro and Canadian are farther south and east, mostly in Southern Utah stretching up to the Uintas.  Obviously our amounts are going to be very dependent on exactly where this band of heavier precipitation sets up.  This uncertainty is reflected in the model ensemble suite:

weather.utah.edu

weather.utah.edu

Still showing anywhere from just a trace to 2 inches of QPF.  I think the most likely range is 0.5 to 1″.  Since this storm is splitting and then the southern split moderates and we primarily see a SW flow during the storm, snow levels will be much higher than our last storm.  Likely starting out Sunday night above 8k feet, then lowering to 6-7k feet on Monday.  Accumulations on the higher mountain are very tough to call, but based on what I’m seeing, generally 3-6″ is likely, but 6-12″ could be possible if the band sets up over a specific area.  Like I said yesterday, perhaps it’s just best to set expectations low with so much uncertainty.

Storm #2  

Another storm timing for Wednesday night into Thursday.  This one is just barely going to graze far northern Utah.  Probably just a dusting for the Northern Mountains.  But if it does trend slightly deeper and stronger, we could get a few inches.

Storm #3

Friday night into Saturday it looks like we have another good shot for mountain snowfall.  GFS has this storm as fairly weak and more of a brush-by.  The Euro is stronger and deeper with the storm.  We’ll have to watch this.

Storm #4

This one is for early in the week following Thanksgiving (November 28-29).  Both GFS and Euro have this system.  While they have differences in timing and structure of the storm, both models have it as stronger than its predecessors.

Long range:

In general, the active pattern continues as we head into December and hopefully these storms start packing more of a punch.  If so, we will be able to catch up on our snowfall deficit quickly!

WSF





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  • Jake

    I think this is the first entirely positive post of the year

  • Satans Humble Garden Gnome

    This November really turned around. It seems we’re about to get a whole lot of snow before the end of November

  • Chad Niel

    If anything starting the season this way instead of with a boom puts our expectations are lower ¯_(ツ)_/¯