Happy Thanksgiving!…and happy snow day too

Posted Thursday, November 22nd, 2018 by Pete Saunders

First of all, Happy Thanksgiving to you all! I hope everyone is having a restful time with friends and loved ones. I also hope that, like me, you plan on stuffing yourselves full of turkey and sweet potato casserole…


The short and sweet

Expect a series of troughs to push through the area today through Saturday afternoon with fairly significant amounts of snowfall across northern Utah mountains. Snow has already started falling in the mountains today, but the heaviest snowfall will occur between Friday night and Saturday afternoon. There also will be very strong winds at higher elevations during that time too, though. Quiet weather enters in Sunday through the middle part of next week.


Current Weather

Weather-wise, there’s a lot to be thankful for today. We’ve broken the inversion and welcomed in one of two main troughs that will be decent snow producers for the mountains. Below is a webcam view of Sugarloaf Peak at Alta at 12:12 PM MST. Looks like it’s nuking out there!

Web cam from Alta's Sugarloaf Peak at 12:10 PM MST. Courtesy: www.alta.com
Web cam from Alta’s Sugarloaf Peak at 12:12 PM MST. Courtesy: www.alta.com
Snow stake at Snowbasin at 12:25 PM MST. 3"+ have fallen so far there. Courtesy: www.snowbasin.com
Snow stake at Snowbasin at 12:25 PM MST. 3″+ have fallen so far there. Courtesy: www.snowbasin.com

By the way, here’s a recap on current openings and future opening days for Utah ski resorts:

Brighton – OPEN
Brian Head – OPEN
Alta – November 23
Deer Valley – December 8
Park City – OPEN
Snowbasin – OPEN
Snowbird – November 24
Solitude – December 1
Sundance – December 7


Today

As the trough moves through this morning, expect snow intensity to remain fairly heavy through the early afternoon, then taper off in the late afternoon/early evening by 4:00 PM MST. There likely will be some lingering snow showers in the mountains through the evening with orographic lift from northwesterly flow. Overall, snow totals for today look decent with 5-9″ in Park City area resorts, 8-12″ in the upper Cottonwoods, 4-8″ at Snowbasin and 3-7″ at Sundance.


What about that “Bigger, Badder” trough we’ve been talking about?

That’s still on the way! Tomorrow morning, remnants of a trough currently off the Oregon coast will make its way into northern Utah (with the bulk of the energy staying in southern Idaho). However, in the morning through the afternoon we should expect snow accumulations in the 3-5″ range for Park City, 4-8″ in the Cottonwoods, 4-8″ at Snowbasin and 3-5″ at Sundance.

After a brief lull in action late Friday afternoon, by Friday evening lift ahead of the incoming bigger trough will allow for an increase in precipitation intensity through the night Friday and into the day Saturday as the trough passes through Saturday afternoon. Below is a 500 mb vorticity chart valid Saturday at 1800 GMT (1100 MST) from today’s 1200 GMT GFS run showing that upper level trough pushing into northern Utah. Note the ample amount of northwest flow over our region as the trough moves through. This is good for lower density snow, or “powder”. One thing to note, though, is how windy it could be Friday night through Saturday morning in the mountains. Winds could gust up to near 50 kt (60 mph) at higher elevations. They should diminish a bit through the day on Saturday but still might be in the 30-35 kt (35-40 mph) range at or near the top of some peaks. So, unfortunately a lot of this snow could be blown around/away…and could also make for dangerous conditions on the mountain. So BE CAREFUL!

GFS 500 mb vorticity (with geopotential heights and winds) valid at 1800 UTC tomorrow morning. The cold Pacific trough will move push into northern Utah during the day tomorrow.
GFS 500 mb vorticity (with geopotential heights and winds) valid at 1800 UTC tomorrow morning. The cold Pacific trough will move push into northern Utah during the day tomorrow. Courtesy: tropicaltidbits.com

The GFS is a little bit more excited about this storm’s precipitation potential, and it forecasts the greatest snowfall amounts in the upper Cottonwoods compared to areas north near Ben Lomond. The ECMWF is a bit more conservative with snowfall amounts, and has a bias in the mountains north of SLC. With the trough still a couple of days out, and with a bit of model disagreement still, it’s a bit tough to nail down exact snowfall amounts, but in general we can expect  fairly significant amounts of snow in the mountain resorts Friday night through Saturday with 10-14″ in the Cottonwoods, 8-12″ in Park City area resorts, 6-10″ at Snowbasin and 5-9″ at Sundance.

The trough will move quickly through the area Saturday, leaving us mostly dry by the evening as ridging builds in. The totals from today through Saturday look great though! Here’s summary of forecast accumulated snowfall for the week as of now:

Cottonwood resorts (Alta, Snowbird, Brighton, Solitude): 20-32″

Park City area: 16-26″

Ogden area (Snowbasin, Nordic Valley): 14-26″  

Sundance: 11-21″

Friday and Saturday snowfall forecasts will be refined tomorrow as model guidance on the incoming trough should be better represented in future model runs.


Next Week

As ridging builds in on Sunday, expect dry and calm conditions to enter in for at least a few days. Models are hinting at another active weather pattern starting as early as Wednesday evening, though, with the potential for several more chances of mountain snow! Below is the ECMWF ensemble mean 500 mb height anomaly chart for a 5 day period between next Wednesday and the following Monday. Blue/purple/green contours indicate a more trough-like pattern, and yellow/orange/red contours indicated a more ridge-like pattern. We obviously want the trough-like pattern for snow as this would likely give us a chance for some low-pressure systems to make its way through the region, so it looks like things could get pretty interesting again!

ECMWF ensemble 5-Day mean 500 mb height anomalies. Blue/purple/green indicate a more trough-like pattern and yellow/orange/red a more ridge-like pattern. This chart indicates that between 00Z 28 Nov and 00Z 3 December (next Wednesday and the following Monday) we could see a rather stormy/snow pattern.
00Z 22 Nov ECMWF ensemble 5-Day mean 500 mb height anomalies between 00Z 28 Nov and 00Z 3 December (next Wednesday and the following Monday). Blue/purple/green indicate a more trough-like pattern and yellow/orange/red a more ridge-like pattern. This chart indicates that we could see a rather stormy/snow pattern toward the middle and end of next week. Courtesy: models.weatherbell.com

Enjoy the dawn of this base-building holiday weekend, and stay tuned for more details on next week’s potential stormy pattern!

Pete

 

                                                                                                                                                                                                                            

 

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