The Weekend Update

A soggy cold morning with some light to moderate snow showers. Temps aren't all that cold in the Salt Lake Valley, ranging from 32-36F across locations. Looks like temps remained a bit too warm and snowfall rates at bit too light for any meaningful accumulations on the roadways this morning. I think some minor slush or a skiff occurred up along the benches, but otherwise no significant valley impacts. 

View from Alta, UT base 12/5/2025

The mountains are fairing a bit better in terms of snow, with 2-3" already reported at the ski resorts. Moist northwesterly flow continues today through tomorrow, which will supply the fuel for ample orographic lift along the Wasatch. These are the conditions when the Wasatch can live up to their reputation. 

Will the Wasatch Whale provide?

The forecast for the storm today - Friday 12/5/2025 - through the first half of this weekend remains on track from the previous discussion I posted. 

1. An atmospheric river (AR), arching over an upper-level ridge located across the eastern Pacific, will continue to feed moisture and energy from the NW into Utah Friday through Saturday afternoon. 

   

   Analyzed 700mb heights, temps, winds, and RH 12/5/2025 @ 1600Z

2. A relatively strong jet streak, associated with the AR, with setup across northern Utah providing energy and lift for more enhanced precipitation. 

   

   Analyzed 300mb heights, temps, and winds12/5/2025 @ 1600Z

3. Warm air advection mid Friday through Saturday morning will bring warmer temperatures into the state, lifting snow levels from the valley floors to around 7000-7500' by Friday night/early Saturday morning. 

   

   Alta, UT - Top: Wet bulb zero level (proxy for snow level); Bottom: Snow ratio (density)  (source: UoU Atmo Sciences)
   

4. Valleys will see snow change over to rain Friday afternoon and continue into Saturday.
5. The heaviest snowfall rates in the mountains will occur late Friday through Saturday morning as the main surge of moisture and energy make across northern Utah. 

   

   ECMWF 00Z 12/5/2025 6-hr snow accumulation

   
   
6. Mountain locations could see 1-2.5" of SWE and 12-30" of snow. Potentially localized areas of 30"+ in favored locations such as the Cottonwoods. 

   

   Total Snow 10:1 (in) 12/5-12/8/2025 - Left: ECMWF 00Z 12/5/2025; Right: GFS 12Z 12/5/2025
   

   
   
7. Cooler air will fill back into the region at the tail end of the storm Saturday morning through the afternoon, but by this point precipitation coverage and rates will already begin to trend downwards. 
8. Snow showers in the mountains look to end by Saturday evening/night

That's pretty much this weekends storm in a nutshell. Should provide part of an answer to Utahn's prayers for snow. Nevertheless, even with the relatively significant snow and liquid totals in the mountains over the next 24hrs, this storm is still not this season's savior. Even if the Wasatch manages to squeeze out the top end storm totals - 2-2.5" SWE or 20-30" of snow -, this will not make up for the unprecedented lack of snow thus far. SNOTEL sites were still reporting the lowest snowpack to date on record for many sites in the Wasatch as of yesterday. There is still a long way to dig us out of - or rather fill in - the current state of the snowpack in northern Utah. 

Snowbird SNOTEL Dec. 4th Snow Water Equivalent (SWE) 1989-2025. Red star represents the SWE for 2025

I'm sure the powder fever is going to hit people hard this weekend, with many already shaking and foaming with excitement. I'll bet on the canyons becoming a mess and drivers shrugging off patience and decency in an attempt to get up to the ski resorts as fast as possible. I hope I am wrong and this weekend goes without a hitch. Some may even be of the impression that this is finally the light at the end of the tunnel, but unfortunately I consider this storm to only be a band aid on the open wound that is the Wasatch snowpack. A number of storms of this caliber are needed to get us to "normal", and unfortunately the long-term doesn't look so optimistic but that is always open to change. In the meantime, keep on praying hard or ask Santa for snow this Christmas... 

UDOT sign Big Cottonwood Canyon 2025