Thanks for a Great Season

With the usual rowdy send-off, Alta shut down the lifts on Sunday, and once Brighton closes this coming Sunday, Snowbird will be the only resort still open in Utah. While they will probably stay open through at least the end of May, we are hanging up our forecasting hats for the season.

It was a pretty awesome one, despite an extremely warm February and record warm March. The savior for us was the fact that precipitation was well above normal…one of the wettest in recent memory at many sites. This should mean that the high elevation snowpack will last for quite a while for those that like their summer skiing. Thanks for visiting our site, and we look forward to seeing you again when the snow starts flying in the fall!

-Peter

One Last Storm?

Yesterday’s storm ended up being a disappointment for the mountains. We weren’t expecting anything much, but I know I was holding out hope for a shower or two up in the mountains. Alas, all we got was some dust on the snow. The frontal passage in the valley dropped temperatures by 20°F, and the temperature difference was still strong in the mountains with Alta-Collins seeing a 13°F cool-down in one hour. And high temperatures today were much cooler than they were for the last few days–the first day since Sunday that we didn’t break 32°F.

We have one more day that won’t break the melting point in the mountains (at least in shady spots–the sun is intense), and then we’re back to spring temperatures. By Sunday mountaintop temperatures will be flirting with 40°F, though the 50s will hold off for a while. We have another storm on the docket, though details are still a few days away.Screenshot_20170414_210853

The spread on this ensemble highlights how there is a general concord on timing with a storm arriving Tuesday afternoon. However there is no consensus with precipitation amounts, and small changes in how the atmosphere evolves will lead to diverging storm totals. Another thing that’s up in the air (pun not intended) is the temperature of the storm. While most guidance leans towards a very high snow level at least for the first few hours of the storm, I can’t rule out something colder and snowier.

Springtime Lull

With temperatures steadily increasing in the valley this week, it’s feeling solidly like spring (even summer, for those of us from cooler climates!). The next few days should bring some fairly dynamic conditions, with a weakening trough approaching from the west.

GFS 500 mb Height Field Thursday into Friday
GFS 500 mb Height Field Late Thursday showing mid-level SW flow and the approaching trough

At first glance, it seems like this might be a trough that delivers a decent snowfall, but a closer look at the models show energy dissipating as the trough moves inland, with little moisture associated with it in the first place. We can expect temperatures at elevation to climb into the 50s for Thursday on the warm southwesterly flow as winds increase, especially at mid-elevations. Clouds will increase throughout the day with what moisture and lift is available, with the potential for mixed rain/snow showers overnight into Friday.

NAM Time-Height, noting the passage of a shallow front early Friday.
NAM Time-Height, noting the passage of a shallow front early Friday.

There’s some decent mid-level instability overnight into Friday morning that could produce periods of heavier snow showers in the upper Cottonwoods and high on the Park City ridgeline, though that support will be short lived. If snow showers continue into late Friday and Friday night, they will likely be light and sporadic. I’d say it’d be reasonable to expect 1-3″ at upper elevations with a trace to 2″ at mid and lower elevations. Being spring, surprises can happen, but the models have been indicating this system weakening for a few cycles now.

Back to April

Oh what a day it was on Sunday…I had one of my best powder days of the season, and I heard many other skiers saying the same. Some bold claims were made:

 

Unfortunately, after our brief blast of January conditions, the April weather is coming back. We will get brushed by a storm Tuesday, which will bring us mainly just some clouds. Wednesday looks to be beautiful, sunny, and warm, with above average temperatures…definitely the best day to get outside this week.

 

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The GFS model forecast for Wednesday…big ridge of high pressure with blue skies and warm temperatures.

Clouds will begin to increase late Thursday as our next storm moves in on Thursday night, which does not look overly impressive. It should be good for some snow in the mountains and a cool-down, but probably not a powder day. The storm looks to exit the area early Friday, and the temps begin to warm up again.

Beyond that, the next potential for precip could be early next week, but confidence is low on that. Most of the remaining open ski areas in the Wasatch will have their closing days on Sunday, so make sure to get on it! Snowbird, as usual, will likely be open through at least Memorial Day.

Wet and Wild

I woke up this morning with a view of snow on Mount Van Cott. Overnight snow levels must have dropped to ~6000′ with the heavy showers that affected northern Utah in the early morning hours. While a lot of water fell from the sky this morning, not all that much snow made it. The coating on Van Cott was gone nearly as soon as the sun came out, and Alta only had ~4″ of snow from the nearly three-quarters of an inch of water.

This weekend we get more than one shot at good snow, however. First was this morning, and then there were the thunderstorms this afternoon. Next is a broad area of moderate precipitation moving in from the west. This radar clip is the very image of hope. There is a lot of moisture downstream, so if all goes well the Cottonwoods will get a good soaking tonight. And, since snow levels are at 7700′ feet right now (and are only going to drop further), most of the incoming precipitation will be snow.Screenshot_20170408_190320

As far as amounts go tonight, the consensus forecast for tonight through tomorrow morning is for around an inch of water. With mountaintop temperatures being what they are, ratios aren’t going to be the best, but they’ll be pretty good for mid-April. The high elevations in the Cottonwoods can look forward to 8-12″ of snow through the end of the day Sunday, while lower spots will have to make do with 4-8″. This is exactly the sort of refresher we needed to cap off the spring.

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An ensemble of probabilities for tonight at Alta-Collins in SWE

April Showers

Weekend warriors rejoice, another weekend of good skiing with fresh powder is on tap. A classic Spring storm system is upon us, evident by the strong winds from a tightening pressure gradient and approaching cold front. Other than the occasional brief shower, the bulk of the precipitation will begin moving in overnight (late Friday/early Saturday). An initial shortwave trough will bring the cold front into Northern Utah and it should remain stalled there during the day Saturday. I think the big winners during the day will be the far Northern Wasatch including Beaver Mountain. My one concern is the warm temperatures and high snow levels – Beaver Mountain with a base elevation near 7000 feet will likely be flirting with rain lower mountain. Make sure you bust out your best goretex – it’s going to be a wet one!

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ECMWF forecasted precipitation during the day Saturday
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ECMWF 700 mb temperatures Saturday

 

 

 

 

 

 

 

 

 

 

Saturday night is when the storm should begin really producing the goods for areas like the Cottonwoods. The meat of the trough will move across Northern Utah and begin to tilt negatively as it moves towards the east. Without getting too much into technicalities this storm will have some pretty good dynamics associated with it. In addition, 700 mb temperatures will crash below -10 C Saturday night. With favorable moisture for a cold, moist NW flow this is combining to be the perfect recipe for a solid Spring powder day on Sunday. For totals I’m expecting 8 – 16 inches ABOVE mid-mountain for the Northern Wasatch. With favorable NW flow I think the Cottonwoods should come out in the 12 – 20 inch range.

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Time height cross section showing frontal passage and moist NW flow

Start getting excited

Alex cautioned us on Monday not to get too hyped up just yet for this weekend’s storm. I’m not quite on the hype train like famously loud and excited storm chaser Reed Timmer, BUT I am start to get excited.

Hype train featuring Reed Timmer and infamous OK Met Mike Morgan. No idea who to credit with this masterpiece.
Hype train featuring Reed Timmer and infamous OK Met Mike Morgan.
No idea who to credit with this masterpiece.

Why am I getting excited? For many days now, multiple weather models and their ensemble systems have been depicting a strong storm with heavy precipitation over Utah for the Saturday-Sunday period. The fact that there has been a long period of similar model solutions for the weekend, with different weather models arriving at this same solution, and their ensemble systems supporting this as a likely outcome…that gives me a good amount of confidence that we can expect a big storm this weekend.

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Sat-Sun precipition from the GFS (left) and the ECMWF model (right). Both depict a big event. models.weatherbell.com
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Precipitation output from the ECMWF ensemble members at SLC. Almost all of them are on board with a big event.

The question, however then becomes “what will the snow levels be?” The answer is looking like “all of the above.” They look to start very high on Friday night, lowering through the day Saturday, and then reaching the valley floor by Sunday morning. These types of details will evolve somewhat as the event gets closer, but I think this evolution looks pretty likely.

In the meantime, Thursday looks like a really nice day to be outside, with sunny skies and warm temps. Friday also be warm, but the winds will pick up and light precip will begin to move in, especially later in the day.

 

Don’t Climb Aboard the Weekend Hype Train Just Yet

As some of you might of heard by now, some forecasts are calling for a modest snow event this weekend.  I don’t want to completely curve your excitement for this possibility, BUT it is also important to remain realistic.  Forecasting snowfall in the northern Wasatch is extremely difficult 5-7 days out.  Snowfall in the Wasatch is strongly dependent on moisture availability, flow direction, flow speed, and 700 mb temperatures.  All of these above parameters are dependent on the exact location, trajectory, and strength of the upper level trough as it moves into Utah.  Forecasting the exact location of the upper level trough 5-7 days out is unrealistic, and thus, forecasting exact snowfall 5-7 days out is nearly impossible.

What models can tell us 5-7 days out though is the likelihood for a pattern change.  Model ensembles can show us if the deck of cards is stacked in our favor for potential unsettled weather.  Below is an image of the European Ensemble 500 hPa anomaly (blue to purple colors represent lower pressure while orange colors represent higher pressure), which shows the potential for a longwave trough over the western U.S this weekend.

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European Ensemble Mean for 12 UTC (6 am) Sunday morning. Courtesy of weatherbell.com

Before getting to excited, we should investigate the uncertainty within the forecast. Below is an image from the Canadian Ensemble 500 mb heights for Sunday morning.  The black lines represent the mean height field while the red letters represent locations of the upper level trough for each ensemble members.  Where these red letters are closer together, there is a higher confidence in the location of the trough and where they are further apart, there is less confidence.  Notice how the red letters below are far apart across Oregon, Washington, And Idaho?  What this boils down to is there will likely be a trough across the western U.S. this weekend, but there is no way to tell if the trough will dig down into Utah – giving us snowfall and colder temperatures – or merely give northern Utah a glancing blow.

 

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Canadian Ensemble Forecasts for April 9th at 12 UTC (6 am). Courtesy of https://weather.gc.ca/ensemble/index_e.html

What’s the bottom line?

We will see a pattern change this weekend with the potential for unsettle weather across northern Utah and we will likely see a storm system impact Utah this weekend, but we can not estimate the exact strength of the storm, and associated snowfall accumulations, at this time.

 

 

We Have a Long Week Ahead of us

It snowed today! A few precious inches fell in the mountains. It was wet stuff with meager 10:1 ratios, but I hope you enjoyed it. It’s all we’re getting for a while. High pressure is going to dominate over the next week, and, while I refuse to rule out the occasional light mountain shower, any decent storm will have to wait till next weekend.

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The reason for the (dry) season

At least we’ll have a couple of relatively cloud-free days in there to enjoy the spring weather.

Warmest March on Record

After an incredible December – February for powder skiing, March was certainly a let down. This March will go down as the warmest on record for Salt Lake City. The low elevation snowpack has been seemingly torched at this point. Fortunately, upper elevation sites above 8000 feet are still fairing pretty well. The losses in snowpack below, however, are quite noticeable. This March also marked one of the wettest on record for SLC, however, the mountains did not reap a lot of those benefits. The warm temperatures meant most of those storms came in with high snow levels, and we even had a few storms that produced more QPF at the airport than in the mountains – bummer.

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I don’t want to be too much of a downer, though, since this season has been great and the best in several years for Northern Utah. The Upper Cottonwoods, for instance, are closing in on 500 inches, and we still have more ski season left! How are things looking this next week?

Unfortunately, the storm for Sunday/Monday has continued to trend weaker in the models and now doesn’t look like much more than a few inches. Dust on crust conditions look likely for the next few days until mid-week when things clear out. This will hopefully soften up snow a bit and maybe even bring about a brief corn cycle if we can stay clear for a few days. The next potential for a “big storm” looks to be next weekend.