High clouds have spread across our area today along with gusty winds at ridgeline ahead of an upper level low near the Oregon coast. Southerly flow will continue as the low approaches our area tomorrow from the west, and starting around lunch time we should begin to see pre-frontal precipitation in the mountains. Given the setup I wouldn’t be surprised if the best pre-frontal precipitation is in the Oquirrhs. By mid-late afternoon the front will be knockin on our doorstep and associated precipitation will quickly increase along the Central and Northern Wasatch. My best guess for max snowfall rates is from late afternoon (around or just before lifts stop spinning) until around midnight. Things will then begin to taper off Thursday AM as a dry slot punches into Northern Utah from the SW. Beyond Thursday models are in fair agreement showing the upper level low cutting off and meandering around the region for a couple days. This could help maintain at least a slight chance for snow showers through the weekend.
Overall, a quick look at most model guidance yields about .4 - .6” of liquid precipitation (SWE or QPF for weather gurus) across the Wasatch in Northern Utah through Thursday PM. The highest amounts unsurprisingly showing up in the higher resolution models. The flow direction isn’t favorable for preferential orographic enhancement in the Cottonwoods, and I wouldn’t be surprised if any of the far Northern resorts outperforms the Cottonwoods. One thing going for this storm, however, will be the cold temperatures (700 mb temperatures < -10 Celsius and ratios ~15:1 – 20:1) – thus it won’t take a lot for snowfall totals to quickly pile up. All this being said, I’m expecting 6 – 12 inches for the Cottonwoods and resorts in the Northern Wasatch (Snowbasin, PowMow, Beaver Mntn) and 4 – 8 inches in Park City (slightly lower amounts for Sundance). Probably your best bet for fresh pow is first thing Thanksgiving morning. And remember, while it may look really nice off trail, be careful of those hidden treasures (rocks)!
Happy Monday! I hope everyone was able to get out this past weekend and enjoy the beautiful, late-November weather! Coming from Oklahoma, I still can’t believe that I was able to ski on Friday, then hike in City Creek canyon on Saturday in a t-shirt. Gotta love these western winters. Well, except for the awful visibility we are experiencing today in the valley thanks to the strong, surface-based inversion that has built in.
As Ian mentioned in his post, this pattern is looking quite similar to the one we forecasted for just a week ago. With the holiday approaching and some precious days off work, I know all of you would be thankful for a few inches of fresh powder to shred... Let’s see what we have to work with.
Synopsis: Mild, pleasant weather expected for northern Utah through Tuesday with highs in the mid-50’s and a southerly wind. A weak, upper-level short-wave trough may increase southwesterly flow on Tuesday, but won’t result in anything as far as precipitation is concerned. On Wednesday, the weather becomes more interesting. The latest model guidance seems to be agreeing on a slower progression of the impending cold front that will bring frigid temperatures to the valley on Wednesday evening. This slower progression will allow for the possibility of a longer duration snowfall on Wednesday afternoon. This deep upper-level trough appears to have enough energy (relative vorticity for you weather weenies), but the availability of sufficient low-level moisture may be the restricting factor on a truly epic snowstorm. This cut-off low appears to want to meander around the Great Basin through the weekend, so there is definite potential for lingering snowfall.
Early Snowfall Projections: Forecasts change everyday as new information becomes available, so I think I am going to deviate from Ian’s forecast a bit. I think this storm should be good for at the very least, 6 inches in the upper Cottonwoods through Thursday, with it being a little too early to determine an upper-limit. I am going to give Park City and northern resorts a similar forecast, though I would knock the lower snowfall limit down to about 4 inches. Trey should have a better handle on the mesoscale impacts tomorrow and will give you a stellar forecast, I’m sure of it!
Have a wonderful and safe Thanksgiving holiday!
A quick hitting cold front is approaching the west coast, just like my last forecast 8 days ago! The approach will be noticeable by "warm before the storm" characteristics in the valley Monday and Tuesday this week. The front itself should start to make itself known to Utah on Wednesday morning as cloud cover and gustiness giving way to snowfall and cold winds. A question I asked myself this forecast period was "does warm before the storm hold at mountaintop level?" Well it seems that wind direction from the South / Southwest generally holds, but at higher levels, wind from the south isn't always as warm as it is near the surface, but it certainly is dry. It seems to me that at mountain top level "dry before the storm" might be a more appropriate phrase.
The storm is coming fast and if you are unfamiliar with the workings of our weather models you might be lead to believe their downscaled output at face value, and make a ridiculous Wasatch snow forecast like up to 18" for the Cottonwoods. Unfortunantly this is part of a problem we have noticed with the GFS giving values 3 to 4 times as large as they turn out to be. And even when you run ensembles of different versions of these models, the weather we actually get always seems to be at the extreme low end of the simulated range. Being a snow forecast pessimist, that will be my guidance. Another trend that seems to be happening with these quick and tilted troughs is the Park City side of the Wasatch actually doing a little better than the Cottonwoods when there is some wrap-around flow. So for Wednesday morning through Thursday my forecast is 4-8" for the Cottonwoods and 5-9" for Park City side. A little unorthodox, I know, but you didn't come to Utah Ski Weather to get false hope. I'd love to be surprised, but I really don't see how this trough could give snow totals in the double digits when the previous two that were very similar to this one didn't either. I'm still happy because Thanksgiving is a wonderful time of the year and 4-8" fresh is nothing to turn your nose up at!
Temperatures will increase over the next few days ahead of our next chance for snowfall. A deep trough will bring snow and cold temperatures to Utah Tuesday night into Wednesday, with valley temperatures likely reaching teens by the end of next week. At this time, the models are showing a large spread of snowfall possibilies, but most resorts will likely see several inches. Whether it nukes or not, if you're anything like me then it's blatantly obvious that the legs could use some more early season conditioning.
Snow has ended over Utah by Friday night and the snow totals came in well under our expectations. Snowbasin was the winner with 5". Park City is reporting 4" and the Cottonwoods got less than 3". Saturday through Monday look to be depressingly warm and dry. The air in the Salt Lake Valley might get a little hazy, too. Not a good skier forecast. Right now there is a deep trough and an associated cold front that is progged to move into Utah next Tuesday. However, precipitation amounts out of the storm look. I wouldn't worry about that too much at the moment though. More reliable will be the arrival of very cold temps with that storm.
Despite the unfavorable forecast, the resorts are open and there is snow on th ground. And it's Utah, so we will always get it eventually.