Sleeper Pow Day?

TLDR: A quick-hitting storm will move through Utah tonight through tomorrow morning. Higher pressures will build in by the afternoon on Monday, ending the precipitation.

Currently, the precipitation shield is just to our west, and will steadily move through Northern Utah into the overnight hours. Here’s the latest composite reflectivity image from the KMTX radar:

KMTX reflectivity image from RadarScope at 1930 Mountain time

Short Term Forecast:
Precipitation will continue overnight into the early morning hours. Given the relatively warm air associated with this storm, precipitation will likely persist as rain in the valleys, and could potentially become snow in the high benches. The forecast skew-t log-p diagram, also known as a sounding, from the latest GFS run gives you a good idea of what the vertical temperature profile looks like for this storm. The sounding image is valid for 2 am Monday morning. At the surface, the air is saturated, but the temperature is above freezing, so we should expect rain at the valley floor. The temperature then decreases moist adiabatically to the crest level, or 700 mb (~6.5 degrees Celsius per kilometer). Even at crest level, temperatures will only be about -5C, or 23F, which is not too cold for overnight temperatures.

GFS forecast sounding for KSLC valid at 0200 MST. Image via weather.utah.edu

As far as timing is concerned, mountain snow should start in the next few hours and persist through the early morning. The bulk of the snow should be over well before the lifts start spinning. Here’s the latest HRRR forecasted composite reflectivity – this is an 18-hour forecast valid through noon tomorrow.

Forecast composite reflectivity. GIF courtesy of maps.weatherbell.com

This storm isn’t going to be a crazy one, but will be enough to potentially cause a nice Monday morning power day. Here’s what we are thinking for totals:
Cottonwoods: 5-10″
Snowbasin/Ogden area: 4-8″
Park City: 2-5″

NAM 3km snow forecast valid tomorrow at 1100 MST. Image from maps.weatherbell.com

Ultimately, tomorrow should be a nice day if you’re lucky enough to be able to ski on a Monday! Our next chance of snow is on Wednesday, but I will let our forecasters handle that one tomorrow and Tuesday.

Enjoy!
-Taylor

Get Up and Out!

TL;DR. Great skiing conditions today before the next storm impacts the mountains later tomorrow! Mostly sunny conditions are expected in the mountains today as lingering stratus clouds burn off in the valleys.

Nowcast: Low clouds dissipate in the valley this morning as the previous storm system leaves a developing ridge in the forecast area. In the last 24 hours there has been light snow in the mountains with accumulations around 1-4 inches. Today, expect warmer temperatures in the mountains with broken clouds this morning that are expected to transition to mostly sunny by mid day.

A current look at the mountain from Alta.com

Short-Term Forecast: Warming trends continue tomorrow with highs in the low 30s as north westerly flow aloft moves into the area. Increasing clouds tomorrow will likely arrive overnight with a southerly wind and an approaching trough. This trough is expected to impact the area in the evening on Sunday bringing widespread precipitation. There is a change of warm advection to bring light accumulations Sunday afternoon. Models predict 4-8 inches in the Cottonwoods with this feature, but we will have to keep an eye on the water vapor that is accompanying the trough (depicted below). 

GOES-WEST Water Vapor from the National Weather Service

Long-Term Forecast: The next storm system is expected to impact northern Utah by Tuesday night into Wednesday morning generating light to moderate precip in the mountains and possibly a rain/snow mix in the valley. A ridge will build into the second half of the week. 

Onward

Jackson

Excuse me while I freshen up

TL;DR
Today the mountains will see a dose of snow in the afternoon with a few inches of new snow by tomorrow morning. A quick hitting system will impact the region Monday morning freshening up the backcountry and filling in the skin tracks.

Today through the weekend:
High Resolution Ensemble Forecasts point towards the axis of the trough currently over the region crossing the center of Utah late afternoon/evening. so we should see cloud cover remain through most of the day with partial clearing over the valleys by tonight. Temperatures will remain well above the -7/8 C threshold for valley snow so any precipitation over the valley will fall as rain.  Currently we have isolated showers over the western region and this will begin to affect the valley and Wasatch around 10 to 11:

Mountains should see a couple of inches of snow (as mentioned by Trent in the previous forecast) so plan your drive down the mountains accordingly. Saturday we start to see a small ridge build over the region with northwesterly flow aloft and persist until Sunday. Upstream of this feature there is a trough digging over the western seaboard, which will weaken as it ejects over the region Sunday evening/Monday morning. GFS ensemble members point towards a frontal passage sometime around Monday commute.

Not seeing a strong signal of IVT in the GFS/GEFS guidance but temperatures will be cold enough aloft to allow snow to reach the valley floor. These are the plumes for KSLC as of latest model run.

In the mountains we will see a different story unfold with orographic processes helping to drive some stronger snow. The mean snow fall for ensemble plumes for both Alta and Brighton are sitting around 5 – 6 inches with some outliers around 12-15 (also many runs around 2-4 inches). We will have to watch this closely over the weekend but for right now, I am going with enough snow to freshen up the backcountry and fill in skin tracks.

Tuesday into the end of week:
Monday will be a quick hitting storm that will clear out of the region by the evening with another system sliding in Wednesday morning. NAEFS plumes are starting to notice this with some outliers going a little heavy but I will refrain from mentioning anything else for the next 24 hours.  Ensemble models in fairy tale land for Friday indicate a ridge building over the region.

-Andy

Even When It’s “Bad”, It’s Good.

TL;DR: Although we haven’t been spoiled with the persistent dumpage that we saw last week; weak dynamics, persistent NW flow, and moisture moving through our current ridge have kept snow falling at the resorts. While conditions at lower elevations have been downright DREARY recently, it’s hard to get too down when you look at what has been going on upstairs. Cloud cover and modest accumulations have kept surfaces fresh and shaded from intense periods of sun. Base depths continue to bolster as we look forward to a quick-hitting system for the start of this weekend in Northern Utah. More events on the horizon for the beginning and middle of next week. Seasonal snow totals are fast encroaching that of the starved 2017-2018 winter and we’re really only halfway through.

Racing past the 300″ mark recently with over 100″ of it settled at the upper elevations of Little Cottonwood. Nearby neighbors aren’t too far behind with BCC around 80″ of base depth. Taken from snowbird.com.

Short Term: Those looking to get out tomorrow during the day will likely be greeted to overcast skies, mild temperatures, and winds out of the southwest. A fast-moving and frugal storm is on our heels and will be racing through the Great Basin and into Northern Utah starting Friday afternoon. Keep this in mind while planning your departure time from the slopes tomorrow. While accumulations from this feature aren’t enough for a truly deep-blower day, the snow will fall heavy within a short period. Night sliding on Friday should be quite fun and Saturday morning’s pilgrimage (subject to avalanche control) should run relatively smoothly as far as things currently look. Snowfall by Saturday morning is expected to be within the 3-6″ range with possibly more in your preferred Wasatch honeyhole.

Forecasted GFS meteogram for the Upper Cottonwoods through this coming weekend and following week courtesy of weather.utah.edu. Features to note: tomorrow’s quick couple inches as well as what looks to be a calm-beautiful day on Sunday before another storm rolls through Monday and hints at more in the midweek.

Long Term: We’ve got our eyes set on a clearing day Saturday through Sunday before another (slightly more impactful) system moves in to refresh things for those looking to get after it on Monday. A prevalent holding pattern of low pressure systems hanging out in the Aleutians and Gulf of Alaska should continue to push streams of moisture onshore affecting much of the Western United States through the foreseeable future.

Thanks for reading!

-Trent S. Parker

Benefits of a Dirty Ridge

TL;DR: Waves of moisture will be rolling in from the Pacific with a low amplitude ridge parked off the west coast. No serious accumulations but shots of moisture almost every other day over the next week.

Currently, a weak shortwave trough is exiting the region. Unstable northwesterly flow and anomalously high amounts of moisture in the atmosphere have allowed for light showers and gloomy skies to continue throughout the day. Light showers will continue heading into tonight and should taper off by tomorrow morning as that weak shortwave trough continues to move off to the east. 

Short-Term: Light showers are still possible tonight in higher elevations but should taper off by tomorrow morning. The next chance for some snow will come during the day Friday from a weak shortwave trough moving through the flattened ridge. The dynamics with this shortwave trough are very weak but with the anomalously high moisture surge and the little bit of lift associated with the shortwave will allow for showers to develop along the Wasatch. Accumulations will be similar to what we’ve seen today so I would expect accumulations in the 3-6” range likely.


GFS 6 hour precipitation accumulation Friday through noon Saturday (www.weatherbell.com)

Long-Term: Conditions will be relatively dry through the remainder of the weekend before another shortwave trough looks to dig into the western US during the day Monday. Right now, most models are indicating this trough to split over the western US but vary in the amount of precipitation. Regardless, another round of snow in the mountains is looking likely. We will have a better idea of how much will accumulate when we get closer to Monday.


NAEFS ensemble plumes for Atla, UT (weather.utah.edu)


Another chance of snow around Wednesday/Thursday of next week, but snow amounts are still uncertain.

Overall, showers will continue on-and-off for at least the next seven days, with minor accumulations expected right now. Make sure to stay tuned over the next week with waves of moisture moving in!

-Eric

Mid-Week Action?

After being stuck on the east coast for a month, I am happy to be back in good ol’ Utah. Coming back, we are in the heart of ski season with our second holiday weekend almost in the books. With this weekend being beautiful bluebird days, we may see a bit of action mid-week.

Short-Term
As we head into Martin Luther King Jr. Day, we can expect unexciting weather as an upper level trough is moving through the area. Temperatures are expected to be mild with clouds persisting throughout the day. As we move into Tuesday, things start to get more interesting.

As the upper level ridge pushes out of the region, a series of short wave troughs will allow for some vertical motion across Utah. Expect some flurries or mixed precipitation to occur on and off throughout the day, while the main disturbance moves in at night.

Time heights show sufficient moisture moving into the area Tuesday afternoon through Wednesday (via weather.utah.edu)

GFS time heights show sufficient moisture moving into the area associated with the shortwave trough. The most significant period of precipitation is expected late Tuesday night into Wednesday. The total amount of snow is the tricky part of this forecast.

The SREF ensemble averages point to around 0.8″ of liquid precipitation and about 10″ of snow through Wednesday. However you can see the spread is anywhere from 5″ to 20″, so we will get a better picture as the week unfolds.

Long Term:
Following the shortwave trough, another upper level ridge is expected to push into the region, resulting in mostly sunny skies and benign weather. So if you’re trying to scratch that powder itch like I am, Wednesday is your best bet for the next week.

Holy Guacamole

TL; DR What a week’s it has been for the Wasatch! 95” at Alta since January 9th! Wild weather yesterday with many resorts having difficulty opening terrain. Weak system on Tuesday/Wednesday, then we root for the Euro.

Yesterday was wild. When I woke up at 5:30 am, snow was just starting to fall. Over the next three hours, 6 inches of dense snow fell at my apartment. I didn’t have class until 10:45 so I decided to stay at home to avoid the gnarly roads. By the time I left, they were covered in several inches of sludge. I hope all of you had a safe commute. We haven’t had much low elevation snow this year so yesterday was quite the wake up call.

To those of you lucky enough to ski, heavy snow fell all morning in the mountains with Brighton coming out on top with 18 inches (the 8 am Park City report shows 17 inches in 24 hours and 34 inches in 48 hours, but my guess is accidentally doubled the report as very little snow fell before yesterday morning and nearby SNOTEL sites and NWS spot reports do not support this claim) . I had a few friends at Snowbird who waited all morning for the tram to open, only to be forced to leave at noon due to work obligations. Snowbird’s inability to open terrain possibly prompted them to beef with Solitude on Twitter, whom they claimed only got 2 inches of snow all morning. While common sense suggested this wasn’t true, Solitude only updates their totals once a day so there’s no way to know how much snow they receive during the day. This illustrates the lack of consistency between resorts in snow reporting, which can be frustrating to skiers and riders. Fortunately, Brighton has a SNOTEL site that typical reports similar numbers to Solitude.

Anyways, back to the forecast. Sunny conditions will persist until Tuesday as high pressure builds over the region. I spent most of the day at Deer Valley and the views were tremendous. Here’s a shot looking south towards Mount Timpanogos from the summit of Flagstaff Mountain. Temperatures were in the 20s and the sun was shining. Couldn’t have asked for a better day!

Short Term: Our next chance for snow will be Tuesday and Wednesday. Current the NAEFS plumes show an average of 10 inches fall at Alta, but the spread is enormous. In general the GFS has us wetter and the Euro drier.

Graphic courtesy of the University of Utah

Long Term: Tough to say at this point, but in general the GFS has us high and dry, while the Euro has us in the path for storms (not a deep trough, but stormier nonetheless). I say its time to root for the Euro!

Graphic courtesy of WeatherBell
Graphic courtesy of WeatherBell

Winter weather in the Rockies can be a game of inches. A few hundred miles can be the difference between endless powder and sunny skies. Let’s hope we end on the right side of the stormy divide. Thanks for reading and have a great MLK weekend!

Tanner Visnick

@telellama

Snow on Tap

Happy Thursday, everyone! This forecasts comes to you from the American Meteorological Society in Boston, MA. Several of the USW forecasters are here in Boston, learning from our peers and experts in the field. It’s always nice to see friends from all over during this week, but I know I’m looking forward to getting home to my Utah snow tomorrow!

TL;DR: It’s going to snow early tomorrow morning….!!!!!!

Short Term:
As advertised by Jackson and others earlier in the week, a cold front will move across Northern Utah during the overnight hours. With this cold front, expect falling temperatures and sufficient moisture which will support several hours of moderate to heavy snowfall, especially at the high elevations. This trough will be a quick-hitter, moving through the region in just a matter of a few hours.
Shown below is a cross-section extending southwest from SLC to just across the Nevada state line. This cross section depicts the vertical structure of the atmosphere, highlighting the frontal passage and the vertical motion (purple/gay shading) associated with it, as forecasted by the NAM 3km. This plot shows the strong ascent that will exist as the cold front crosses our area. This will aid in strong orographic ascent, resulting in heavy snow at periods in the mountains.

Ahead of the front, gusty south-southwesterly winds will continue. Wind gusts could exceed 90 mph along the ridgelines of the Northern Wasatch. As the front passes, expect the precipitation to be in the frozen form all the way down to the valley floor. This frontal passage will occur around 10Z on Friday morning (5 am MST), which is just in time for the morning commute. It could be a bit messy/slushy out there, so be careful and take your times on the roadways! Below is the GFS forecasted time-height cross section for KSLC, showing the timing of the moist, cold air with the front.

Despite the rapid movement of the trough across the area, this system will still produce a moderate amount of snowfall in the Wasatch, with localized areas of higher snowfall totals near Ogden. Here’s what I am thinking as far as snow totals go. Below is a NAEFS Ensemble forecast of accumulated snowfall for Alta Collins
Cottonwoods: 5-10″
Ogden-area resorts: 6-12
Park City: 3-6″


-Taylor

Blue Bird Day With Snow on the Way

TL;DR Conditions are perfect if you are lucky enough to make it up the mountain today. A current look at the Alta cam facing Superior shows clear skies. This will quickly change as we have another storm system impact the area Thursday night.

Image from Alta.com

Short Term: The previous storm system left early this morning and leaves a developing ridge over the forecast area that will continue to build over Utah tomorrow. This will give the mountains a brief break in snow until Thursday night. Southerly winds are forecasted to increase throughout the day today and persistent into tomorrow as yet another trough impacts Northern Utah. Tomorrow looks to be warmer as a Southwest flow moves over Northern Utah with highs in Alta reaching the low 30s. A stronger trough is building in the Eastern Pacific and will eject across CONUS impacting the area Thursday night into Friday morning bringing colder temperatures, higher winds, and… yes more SNOW. This system could bring 4-8 inches with potentially higher amounts in the Cottonwoods. The duration of this storm is expected to be brief with an upper level ridge moving in late on Friday.

Picture of the forecasted system strengthening on Thursday (TropicalTidbits.com)

Long Term: Weekend skiing conditions look favorable to enjoy the accumulated snow with warmer temperatures and good visibility. It looks like this active pattern of storms that we have been experiencing may be on hold in the near future as a ridge builds in the area and a high pressure system lingers over Utah in the near future. 

Jackson

Friday, Friday, gotta get…

I won’t apologize for Rebecca Black’s inspiring lyrics. Get me pumped for weekend powder.

TL;DR
Snow showers will remain over the mountain regions tonight with a brief respite tomorrow as another system amplifies over the Pacific throughout the day and into Thursday. The storm will eject over the region Friday bringing a decent amount of snow to the Wasatch Mountains. There is some uncertainty in the Integrated Vapor Transport, which could correlate to more snow than what we current models are depicting, so keep an eye out for the next forecast. Either way, fresh snow and bluebird riding conditions for the weekend as a ridge builds over the area Saturday.

Analysis:
Currently Utah is just east of this shortwave trough axis, this feature is placing Utah under an area of upper divergence, along with the surface front, which is helping drive the snowy conditions outside of my window here at the University of Utah. Frontal passage was sometime around noon, which we can verify by looking at temperatures at the Salt Lake City Airport (notice the change in wind direction as well). Data from Mesowest; the best in the business.

Colder temperatures will move into the region later today as this trough passes over us with mesoscale analysis indicating around -14 C to -16 C at Lone Peak Mountain height later this evening. Winds will stay strong and switching to a more West/Northwest component at these heights as well.

Tuesday through Friday:
Current HREFv2 ensemble 500m wind and height output depicts a west-to-east (zonal) flow settling in to the region by midnight tonight. This translates to diminished upper dynamics aloft which shuts down some of the ingredients we need to form heavy snow; however, we will have a cool northerly airflow in place which with some orographic lifting, could squeeze out some snow overnight but shutting down after midnight; current SREF plumes agree with this outcome as well. However, confidence is high that isolated snow showers will remain in some parts of the Wasatch for the morning period.

What is getting me excited is the amplification of an upper level trough over Pacific through the day Wednesday and into Thursday. This feature will bring strong snowfall to the region for this weekend’s backcountry palooza. (Every weekend is backcountry palooza)

Now this system does not look like the most impressive thing out there but what I am interested in is the GEFS ensemble Integrated Vapor Transport. If you were just using the GFS deterministic you might miss this but the ensembles are showing some IVT transport into the region associated with this storm.

It’s a weak signal but it is something that we must pay attention to in the next 48 hours. If this surge of moisture strengthens at all, we will see a very different outcome for Friday’s storm.

As far as timing of this system both GEFS and EPS ensembles indicate Friday afternoon as the timeframe when we could see the strongest dynamics. Translation: Good skiing with bad traffic this weekend.

Weekend
Conditions will be mostly sunny Saturday and bluebird Sunday as a nice ridge begins building over the Great Basin Saturday.

Thanks for reading!

Andy