Snow. So much snow...

TL;DR:

A break is in store for today, then the atmosphere roars to life tomorrow through the weekend with cranking winds and lots of snow.

Nowcast:

It's chilly this morning, with valley temps in the 20s °F and summit temps near or below 0°F. For today, you can expect similar conditions - mountain highs in the single digits, winds that increase in strength as the day goes on, and possible snow showers.

Short term:

The next storm to impact us is something called an atmospheric river, which can be described as a river of moisture high in the atmosphere. You can see the green shading meaning above-average moisture sweeping in from the Pacific and blasting the West like a firehose:

Courtesy of Tropical Tidbits

Atmospheric rivers tend to be (relatively) warm, very windy, and very wet. This storm isn't particularly warm - we'll see 10,000' temps at least five degrees below freezing - but it'll definitely be windy and wet. Take a look at the wind at 250mb (approximately 34,000 feet):

Courtesy of Tropical Tidbits

The red and dark red mean wind speeds of 120-140 knots (140-160mph) and the purple means wind speeds approaching or even over 150 knots (170mph). While most of us obviously don't hang out at 34,000 feet, the meaning is the same - it's going to be windy! Hang on to your hats.

Now, the fun part - how much is it going to snow? Well, the short answer is: a lot. The models have decent confidence in 16-20" in the Cottonwoods and northern Wasatch by 5am Saturday morning, with lesser amounts outside of these favored areas. Beyond this time, the models start to diverge, so I don't feel comfortable putting out numbers; however, it will continue to snow through the weekend.

Long term:

The models are currently giving us a break from snow after MLK Day.

Backcountry comments:

The wind and new snow will stress the persistent weak layer buried in the snowpack; if you will be traveling in the backcountry make sure you have the proper equipment and know before you go. For the avalanche forecast and other avy-related resources, head over to our friends at the Utah Avalanche Center.