Shaping up real nice.

Posted Thursday, February 13th, 2020 by Andy Park

TL;DR
Friday we will have a weak system move over the region which could drive some light snowfall over the mountains but nothing really to note. Sunday we will be hit with storm that is shaping up to be quite powerful which is great because campus is closed Monday!

Short Term:
We can sum up my feelings about Friday’s system with this picture:

Let’s talk about the system on Sunday/Monday.

What are the ingredients we need to see some decent snowfall in the Wasatch?

  • Dynamics
  • Moisture
  • Flow in the right direction
  • Terrain

As this weak system ejects to the east Friday and Saturday another system will begin to develop and slide across the western U.S. As this feature moves, it will amplify and help increase upper dynamics to create an environment for snow to flourish through the life cycle of this trough.

The image above is from the GFS Ensemble which suggests the axis of the upper level trough somewhere over the Idaho and Utah border Sunday evening.

We have dynamics. How about moisture?

Along with this system, the ridge over the east Pacific is steering moisture back into our region:

Wind direction appears to have a little more of a westerly component but still in the right area to interact with the terrain to help drive snowfall.

Temperatures aloft will be quite warm before the front moves over the region with the Euro deterministic suggesting -4 C and GFS deterministic with -6 C at mountaintop levels.  Both models however agree that come Monday morning, we will be facing -15 C at mountaintop levels.

So back to our ingredient list! We have…

  • Dynamics (Associated with the trough moving over the region)
  • Moisture (some moisture from the tropical pacific being steered into the region)
  • Flow (Westerly becoming NW Flow at mountain Top height)
  • Terrain (Nice big mountains for the juicy flow to interact with)
  • Warm-moving-to-Cold-Temperatures aloft during this systems life

I think we can now make sense of the NAEFS plumes to understand that Sunday to Tuesday will be another round of great snowfall accumulations in the mountains starting Sunday and lasting until Monday evening!

-Thanks for reading! Andy

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