The pattern change is arriving, which means that with it comes our first storm of any significance in quite some time. Snow will begin in Northern Utah on Sunday and continue into Sunday evening. Monday morning powder!
Yesterday we talking about the impending pattern change and how it would impact California. There were some questions as to how much of that energy would make it to Utah. Today we have a little bit clearer picture, at least with our initial storm on Sunday.
The trough will barrel into California late on Saturday and the initial wave of precip will push across the Great Basin Sunday morning, arriving in Utah by midday Sunday. Snow in the afternoon and lingering into the evening for the Wasatch. Snow levels will initially be at 7,000 feet or perhaps a touch higher, but should quickly fall down to 5,000 feet or lower as the front moves through. The timing of this storm would mean that it could get good for the last couple hours on Sunday, but the best turns should be had on Monday morning.
As for how much snow for us… The GFS is the most bullish (surprise). It brings through a lot of moisture and drops fairly significant precipitation. The latest NAEFS plumes show this:
I love these graphics and that’s why you see me use them a lot. They show not only a good mean amount, but they also show the level of uncertainty based on the range of the ensembles. Right now, we are at medium confidence, which is to be expected when we are 3-4 days out from the event. The mean shows nearly 2″ of liquid QPF by Monday afternoon for the Upper Cottonwoods. I usually think this is overdone by about 20-30%. So, I’ll say the GFS is showing 1.5″ of liquid for the Upper Cottonwoods which would generally translate to 1-1.5″ for the rest of the mountain range. The ECMWF (Euro), on the other hand, shows much less moisture and a faster system. It puts down about .75″ for the Upper Cottonwoods and .4-.75″ for other areas of the Wasatch. The EC has a dry bias for the region and is also lower resolution and doesn’t pick up terrain as well, so I think that is a bit underdone. With those two major models in mind, and the NAM not yet within range, making a forecast is a bit tricky. I think splitting the middle ground is wise for now. That means .5-1.0″ for most of the Wasatch with 1-1.5″ for the Cottonwoods. This translates to 6-12″ of snow with a foot or more possible in the Cottonwoods. Of course, this is very much subject to change — but it’s an early look at what is possible.
The big change from yesterday then comes for the middle part of next week. Yesterday, models were very much in agreement that, at the very least, additional energy would ripple through the region for much of the week. Now, they have settled on a drier solution in which ridging builds for a few days ahead of the next trough. This will allow us to warm up a bit more than expected with some windy conditions for Wednesday-Friday of next week. The next trough is then progged to move in for next weekend, with snow likely returning. Too early for any details on this storm just yet. It does look like there’s a good chance for another storm beyond that around mid-month but we are out in fantasy land right now…