Friday, January 19, 2024

A classic Sierra steal

TL;DR:

The storm earlier this week has passed. Over the next few days, we'll see decreasing temperatures and some snowfall later this weekend. Due to our active January, most sites are observing SWE above median amounts. 

Nowcast:

Currently, conditions hover around 37 degrees at the base and 29 degrees at the summit. Winds are light and out of the WNW. Cloud cover is mostly cloudy with brief periods of sunshine. Currently, a trough sits off the west coast of the US.

Courtesy: Alta Ski Area

Short-term:

A strong low-pressure trough will make landfall in northern California today. Below is the current upper-level water vapor channel from the GOES satellite. You can see the trough labeled in yellow. 

Throughout the day today and into tonight, cloud cover should increase. I don't expect any snow to start falling until later in the day on Saturday. However, expected snow totals are limited due to the path of the storm tracking over the northern Sierra Mountains and the trough not making it very far inland before breaking up and turning to the north. 

The SREF & NAEFS ensembles vary on this storm, but no members suggest more than 10-15 inches throughout the weekend in upper Little Cottonwood. These values seem high and come in at a 5-7-inch storm total for the weekend. The periods of most intense snowfall will be Saturday evening and Sunday evening, with snow tapering off during the day. Here's the LCC guidance:

Courtesy: UofU ATMOS

Long-term:

The GFS and the ECMWF have the faucet essentially turning off here in the later half of the model run. Some scraps might sneak through to Utah, but both models have two large troughs tracking north into British Colombia. Large-scale blocking or ridging isn't taking place. If you're a frequent USW reader, you know this is quite far out and subject to change.

That's all I've got for today. As always, if you plan on recreating in the backcountry, please check out the avalanche forecast from our friends at the UAC.  


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