So, post-frontal precipitation has been pretty marginal, at least based on the snow depth sensors at the resort, which allows us to do a sort of post-mortem on this latest frontal passage. Alta-Collins is reporting 7 inches since this morning, Snowbird SNOTEL corroborates this number. Ben Lomond Peak, north of Ogden, pulled in about 10", Farmington Peak SNOTEL pulled in about 9", and Brighton SNOTEL went for just over 5". This was all on top of anywhere from 5-15" of snow recorded prior to ~8am this morning.
So how did our forecasts do? well, if you add together the 12" from Collins to the 7" today, we're looking at 19" total, which verifies pretty well, albeit slightly on the lower side from yesterday's projections. Other SNOTEL stations had storm total snow water amounts in the 2" range, putting snowfall totals around 20-24". Overall, a pretty good forecast, although I think that more post-frontal snowfall was initially anticipated (the radar has pretty much cleared out at this point) and the overnight totals observed were higher than we expected (some forecasts called for a lull period between about midnight and sunrise last night).
Regardless, this is a pretty great storm for the Wasatch, especially given the paucity of decent snowfall this season. One would hope that this would bode well for future systems, but unfortunately the trend is to slowly rebound to warm weather under an incoming ridge. The 12Z GFS anticipates the ridge to finally break down around hour 210 (~8.5 days out), but I wouldn't hold my breath for those long-range forecasts to hold true. We'll wait and see...until then, enjoy skiing this sweet freshness, and stay posted here for updates on future pattern shifts!
Wasatch skiers, your patience has paid off. Tomorrow has all the makings for a great powder day so start thinking of your excuse to miss work now. 6 inches fell in the cottonwoods today before lifts closed and it is coming down hard now! There will be a very intense burst now through midnight, then a lull, and then more heavy snow tomorrow morning as the next wave moves through. Snow showers could persist until early Wednesday morning, but not much additional accumulation will fall after lifts close tomorrow. Basically tomorrow is the day, but Wednesday could be great in the backcountry.
I think the cottonwoods will pick up an additional 12+ inches between now and Wednesday morning bringing the storm total to 18-24 inches. On the park City side totals so far are around 3 inches and I expect the snow gradient between the cottonwoods and the park city side to remain consistent so I am going for 9-14 inches.
Because we have gotten some decent snow over the past week the base should be nice and soft and the skiing sublime. Also look for decreasing densities throughout the storm giving the snow some nice body with faceshot potential.
Need another reason to ski tomorrow instead of work? How about the fact that this could be it for snow for the next week or more. We ridge back up after this storm and the long range looks dire. Story of this winter I guess.
Enjoy the storm
Morning Update: things continue to look really good for this storm this morning, so I'm gonna go ahead and up my forecast to 10-20 inches for the Cottonwoods by Wednesday morning. The forecast for the rest of the Wasatch still looks to be on track.
It looks like this weekend's (Sat-Sun) storm totals were generally in the 4-6" range in the Cottonwoods and PC resorts, with 2-4" in other areas like Snowbasin and PowMow. So not a huge storm, but the snow was skiing pretty well up at Snowbird today.
Now on to the exciting stuff: we have a very good looking storm on tap for tomorrow and Tuesday. The models have been consistent in depicting a one-two punch of compact shortwave troughs moving through Utah, with moist west-northwesterly flow in the intervening periods, and cold temperatures aloft. The models have been equally consistent in producing pretty good amounts of precipitation. All of these ingrendients are very encouraging if you are a Wasatch skier. I'm gonna go for 8-16 inches in the Cottonwoods, with 6-12" in the PC area and northern Wasatch by the time the snow winds down Tuesday evening. To get you even more excited, snow densities will likely be very low with the cold atmospheric temps, so I'm expecting blower powder. You may want to consider taking a day off to ski the goodness that is going to be falling.
There is a brief window for lake-effect snow early Tuesday, but with shifting wind direction and inherently low predictability of lake-effect, I'm just gonna mention it as a possibility. Even if the lake does kick in, I don't expect it to be much of an event anyway.
Long range: after snow showers taper off Tuesday night, we come back under the influence of a ridge of high pressure for the remainder of the week. The position of the ridge to our west, however, will allow some storms to brush by us. These would potentially bring clouds and a couple snow showers. Temps will remain on the cool side and the warmup will be modest compared to the temps we got used to in February.
By Tomorrow Morning:
Snowfall rates are beginning to increase as positive vorticity advection and associated 700 mb convergence increases across Central Utah. GOOD NEWS! This axis has continued to shift north over the last several hours with the heaviest precipitation now reaching as far north as the Cottonwoods. A quick look at the Snowbird cam reveals rates up to 1" / hour right now and with 15:1 ratios this appears very reasonable. I'm expecting these precipitation rates to continue through late evening so let's say 6 hours+ of this. I'm going a little bit out on a limb here with my nowcasting, but given these trends early this afternoon I'm going higher than everyone else and forecasting 4-8 inches by tomorrow morning. Everyone from the Cottonwoods and points south should do fairly well. Northern resorts likely won't get as much with a fairly sharp cutoff in precipitation...I'm not expecting much more northward advancement but if it did occur Snowbasin and Pow Mountain would get in on more action.
Tommorow through Monday afternoon:
Precipitation will become more showery in nature without a strong forcing mechanism like we have this evening. Maybe a couple inches especially in areas that get lucky with a few of these showers but not expecting a lot. This would put us pretty close to Matt's forecast of 6-12 for the weekend, though he picked the wrong best day ;).
Monday afternoon through Tuesday:
Another shortwave trough drops down from the NW into Northern Utah. All models are showing that while it won't be an extremely long duration event, precipitation rates could be heavy at times. There's still some uncertainty with the interaction between this shortwave and the longwave pattern entrenched in the Western U.S. but I'm confident enough to conservatively forecast 6 - 12 inches. Don't be surprised if these numbers go up. I really like what I'm seeing with the European and we'll be in favorable (for the Cottonwoods) NW Flow. In addition, there will be a brief period where we could see some lake enhancement. We'll hopefully have a better idea about this tomorrow! In the meantime, enjoy the new snow!
Long story short, the outlook is getting progressively better for the funky trough this weekend. It looks like the Cottonwoods will get 6-12" between Friday evening and Sunday night. This is on top of the 1-3" that fell today. Park City will get just a little less. Snowbasin and Powder Mtn are looking at 3-6".
Most of the snow will fall Friday night through Saturday evening so my guess is that Saturday will be a better day to ski most areas. Sunday might be better if you like to hit areas that are sometimes closed during storms, like Road to Provo at Snowbird. Snow quality should be very good.
The main uncertainty with the forecast this weekend is where the primary snow band will set up. Orographic lift won't play a huge role in this storm, so snow amounts will be sensitive to the positioning of the band. Right now the Cottonwoods and areas south are going to get it. Lets hope it doesn't shift back to the south.
After showery conditions Monday, another storm is currently forecast to move in Tuesday. That one looks like an awesome Cottonwoods storm with moist, cold northwest flow for an extended period. I'll stick with Matt Lammers' forecast of 5-10" for that one, but if the models hold to the current solution it could be more.