As I write this a little after 4 pm Saturday, thw rain is pounding my window in SLC and the cold front just reached the Salt Lake Valley. Snow totals so far in the Wasatch have been disappointing, with the wettest areas getting only 3-4 inches of snow out of up to 0.75 inches of water. This poor snow/water ratio is likely due to a combination of wet snow due to high freezing levels and graupel. I could complain, but its November, and water on the ground is always a good thing, even if its dense.
Looking forward, by 6 pm Saturday snow levels should be at the valley floor. After the frontal band moves out precipitation will turn more showery in northwest flow. The Upper Cottonwoods should do well in the northwest flow through late tomorrow morning. I think the Upper Cottonwoods will wring another 8-16 inches out of the storm by noon tomorrow, with other areas receiving 5-10 inches. Lake effect is possible overnight as well, and my totals hedge a little toward some lake enhancement. This will bring the storm totals up to 12-20 in the Cottonwoods and 8-14 elsewhere. After minimal accumulations Sunday afternoon and night, another shortwave will drop in from the northwest during the day Monday. I expect 3-8 from that last gasp, with the Cottonwoods again getting the upper end amounts.
The long range is currently very depressing. Big ridge for the foreseeable future.
Not a lot of change from Jeff's post yesterday, but I'll say a few words just to put my own spin on things. We can expect snow to begin falling in the mountains around midday tomorrow, starting out on the dense, wet side as pre-frontal temperatures will be near or just below freezing. This combined with ridgeline winds gusting to 60mph will make for some intense storm skiing late in the day, although accumulations before lifts close are unlikely to be much greater than 6 inches.
With sunset, temperatures will drop precipitously, bottoming out on Sunday morning at most ski areas in the low-to-mid teens. Correspondingly, snow ratios will go from <5:1 at the beginning of the storm to pushing 15:1 by late Saturday night. The main thrust of snowfall should occur on Saturday night, with overnight totals (on top of Saturday's <6") of 6-12 inches, with the potential for more in favored areas (Little Cottonwood). For those rolling up the canyons on Sunday morning, that bodes well (along with a tapering off in snowfall early in the morning, meaning roads should be less treacherous).
Sunday holds the potential for light post-frontal snow during the day, although accumulations are likely to be marginal. With a secondary shortwave dropping in Sunday evening, expect some further fresh on Monday morning, as well as the chance for the infamous lake-effect turning on Monday morning to add a couple inches extra. If I had to put a number on this period, I would probably go in the 4-8" range for most resorts, although if somewhere in the Cottonwoods ends up under a lake-effect band, that could add another 3-6" on top.
So where does that put us on storm totals for the Saturday through Monday period (which is what you really read this post for):
- Sundance: 8-16"
- Park City: 10-20"
- Beaver Creek, Snowbasin, Powder Mountain: 15-30"
- The Cottonwoods: 20-40"
Long range I'm not going to worry too much about, as it looks like a ridge sets up over our area at least through Thanksgiving. Just enjoy the freshies this weekend and early next week as areas start opening up. Remember, though, the bases at a lot of these places are going to be pretty meager (Alta opened today with 14"...and most of that is on groomed trails), so don't look at the foot or two of fresh like it's fair game anywhere on the mountain. Also, early-season avalanche rules apply, so don't be surprised if things rip out more than usual.
If all else fails, Ski Fast, Take Chances!
Lots of chatter around town about the upcoming storm, and rightfully so. This storm cycle has the potential to be big. All the ingredients are in place for a big dumpage starting Saturday morning and ending Tuesday. These ingredients are:
1. Dynamics. A very powerful upper level jet currently over the Pacific will impinge on Utah with some embedded shortwave energy. Utah is currently forecasted to lie in the sweet spot for excellent upper level support.
2. Moisture. Said jet is currently busy tapping into some Pacific moisture so it will be plently juicy when it arrives. Would a subtropical moisture tap be even better? Sure, but we can't have it all.
3. Duration. This looks to be a long duration event lasting possibly over 72 hours. It probably won't snow all 72 hours, but there are chances for heavy mountain snow throughout the period
4. Northwest flow. Sorry Sundance and Park City but I have a Cottonwood bias and strong Northwest flow is very favoriable for the cottonwoods.
5. Temperature. This storm is not too cold and not too warm. Very cold storms limit moisture and warm storms limit fluffy powder production. This storm will come in warm, but temps quickly cool to a favorable "snow growth region." It will stack up quickly indeed
6. Lake effect. Always a wild card, but it will be possible from Sunday morning on. Want this storm to be even bigger? Go out to the lake tomorrow with a stove and start heating up the lake. If we all pitch in....
7. Model consistency. Models have been advertising this storm for a few days now and have been very consistent. Things can still change but the bust potential is very low with this storm
Alright so how much? My forecast is for 20 - 40 inches through Tuesday in the cottonwoods. 10 - 20 inches for the park city resorts, and 15 - 30 for the northern Wasatch resorts. Excited? Me too
Saturday will be a storm skiing day with heavy snow developing during the day. Sunday looks like a great powder day. Monday looks like a great powder day. Tuesday looks like a great powder day. I am not sure which day will be the best yet, but we should be able to nail that down better in future forecasts. Stay tuned.
The models are still very inconsistent after Tuesday with the European model sending another good shot of snow for Thanksgiving and the GFS ridging us back up. We will let them duke it out and focus on the medium range forecast for now.
I am so excited to be able to use that word in our first forecast of the season! And that's exactly what we'll be in for starting mid-late day Saturday, lasting through early next week. When we say storm cycle, we're talking about a prolonged period where the large-scale pattern is primed for snowfall, and smaller features moving through this pattern provide the periods of heaviest snowfall. So the snow will be stacking up in spurts throughout this period.
Now for the details and uncertainty in this storm cycle. There has been great agreement in the computer models that we'll be under the influence of a large upper-level trough sitting to our east throughout the period, putting us under a moist northwesterly flow. This type of pattern typically bodes pretty well for lots of snow in the Wasatch, especially the high terrain of Big and Little Cottonwood Canyons. The precipitation output by the computer models has agreed pretty well with this assessment over the past few days. However, as I mentioned above, the periods of heavy snowfall within the storm will come from smaller-scale features in the upper level pattern, and the structure and strength of these features is not well-predicted by the models at these kind of lead times (Monday is still 5 days away!). So as we get closer, the true strength of this storm will come into a little better focus.
To illustrate what I mean, here is a time-height cross section from the GFS model. Ignore a lot of the numbers and variables on there, and focus on the periods of green. These have varied quite a bit in the model runs, basically making the difference between a 1 foot storm and a 3 foot storm for Alta.
But I know everyone is looking for some numbers! So with the caveat that these numbers may change a bit as we get closer to the event, here's my forecast. Drum roll.....I like a general 1-3 FEET for most of the Wasatch where you fine people plan to ski (8,000 feet and above). That said, I would not be surprised if the high elevations sites in the Cottonwoods exceeded these numbers.
Stay tuned for Jeff's forecast tomorrow, as he'll have some more certainty on the numbers. Jeff has also been realllly excited about the potential for a big dump from this storm for the past few days, so he is positively giddy to share his snowfall forecast.
There is still a ton of spread amongst the models and ensembles on the mid-late next week period, so the forecast confidence is fairly low, but it looks like we'll remain in an active pattern after this storm. Keep those skis tuned!
As some of our returning users may have noticed, our website has been redesigned with a totally new homepage! Utah Ski Weather has been around for almost a decade now, so we figured it was time for a little facelift. Now that the ski season is underway in the Wasatch, we plan to post an updated forecast every day, so make us part of your workday procrastination!
Although our written forecast thoughts will now be front and center on the website, don't forget that we still have icon-based 5 day forecasts for the major ski resorts in northern Utah! That way you can still get temperature, cloud cover, and snowfall for the exact place you plan to ski.
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See you on the lifts and the skin track this season