Ridge is breaking down currently. A couple very weak systems tomorrow and Friday before a STRONG system moves in late Saturday through Monday with heavy snow accumulations possible for Northern Utah mountains.
Not too much has changed since yesterday, which is a good thing. Models still carry on with the idea of good storm for this weekend in Northern Utah. First, we’ll have to break down the ridge with two systems. The first one tonight will cross the Great Basin and into Utah. By the time it reaches us, there won’t be much left. Can’t rule out a few showers, with snow above 7k feet, but any accumulations should be minimal. The second systems will split with most of it’s energy sliding down into Arizona.
The main storm moves in starting Saturday morning with precipitation increasing throughout the day. Saturday looks to be a day where you might have a few inches by last chair, but the main powder will be found on Sunday, Monday, and possibly even Tuesday. The initial front will move through Saturday night. By Sunday morning, snow levels should be at valley floors but the main piece of frontal energy will be through the region. This is when orographic lift takes over in a northwest flow. If you’ve been reading these forecasts for awhile, then you’ll know how important orographic lift is for generating our amazing snowfall totals in the Wasatch. This storm will be relying on orographics as additional waves move through the area into Monday in a cold, northwest flow. Lake effect or enhancement also looks to be a factor with areas SE of the lake most likely to see the benefits (Cottonwoods and PC, perhaps?)
As for totals, it’s still very early but let’s look at some preliminary numbers. Here is a forecasted model QPF through Tuesday:
This shows 1 – 1.5″ of liquid in the Wasatch which, assuming 12:1 ratios, would yield 12-18″ of snow. Now, let’s look at the graphical view of the GFS output from this morning’s 06z run:
It shows snow starting early Saturday and accumulating to nearly 20″ by Tuesday morning. So assuming these models are correct, that means 10-20″, right? Not bad…. However, these are low-resolution models that do a poor job at picking up on the orographic influences of the topography or the enhancement from the GSL. Both of which can be wildcards, but it looks like they are good bets for this weekend into early next week. In good orographic storms, it’s possible for us to double the expected amount from the GFS. So, what does that all mean when you tie it together. I think 1-2 feet in the high elevations of the Wasatch is likely Saturday through Monday evening, with the potential for up to 3 feet in areas downwind of the GSL and/or favored by northwest flows.
Of course, it is still early and chances are that things will change in the coming days. Check back tomorrow, Thursday and Friday for updates and we will fine-tune those amounts if needed.
The ridge has looked a bit farther west and not quite as strong next week. The Euro in particular has developed a solution in its last two runs that drops a decent, cold system into the area the night before Thanksgiving Day. GFS has more or less shown this solution in its latest run, just not as deep with the trough. Something to keep an eye on… Signs are pointing to a great Thanksgiving ski week in Utah!