Monday, April 17, 2023

Let's Make a Run at 900!

It may be hard to believe given the dry sunny weather over the weekend, yesterday's high at the Salt Lake City Airport of 74˚F, and today's forecast high of 72˚F, but another cold trough is on our doorstep. 

The GFS forecasts the trough to be pushing into the Intermountain West at 1200 UTC 17 April (6 AM tomorrow morning.  In advance of it, we have a cold-frontal passage with a little valley rain and mountain snow developing overnight.  

Then the deeper and colder part of the system moves in tomorrow.  Temperatures and snow levels will drop during the day and be near the valley floor by 0000 UTC 19 April (6 PM Tuesday), with 700-mb temperatures near -10˚C. 

Thus, don't be surprised to see some flakes around late tomorrow in the valley, although  accumulations look to be limited right now.   

In the mountains, let's begin with recognition of the fact that Alta Ski Area's seasonal snowfall now sits at 879".  That's 21 inches from the coveted 900" barrier. 

The models though have a great deal of spread for this event.  The 12Z HRRR is a real sour puss, giving only 0.16" of water and 2.2" of snow for Alta Collins through 6 AM Wednesday.

The 6Z GFS, on the other hand, is a wet foot, pumping out 0.86" of water and 11.4" of snow by that same time.  The Euro is also fairly wet in the central Wasatch. 

That would put us close to the coveted 900" barrier, but the GFS isn't done.  It brings a couple more weak systems through later in the week, pushing it's total water to about 1.2" and snowfall to 17.5".  

That would put us at...896.5" if it were to verify.  

That's just one model run, but tantalizingly close.  

The GFS is actually fairly wet compared to the various downscaled NAEFS members from yesterday.  Most are under 15", although there are a few above 20.  


I'll put the odds of breaking 900" this week at 35%.  Place your verbal bets below. 

7 comments:

  1. I've got a quarter that says we're not going to make it.

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  2. I think around 40% we will make 900” with the next rounds of storms this week.

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  3. 900 is going DOWN!

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  4. Earlier this month my date was closing day of Alta. I know it’s a long shot, but I’ll stick with it. Let’s go Lake effect snow!

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  5. The HRRR doesn’t like being insulted. At least we got some nice thunderstorms.

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  6. 900 goes down by Sunday closing!

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