Great Weekend Haul, and More Midweek

The weekend brought another foot of snow to the high mountains, and some snow all the way down the the benches. Snow rates were especially good early in the morning Sunday when 2″ per hour was falling for a bit at Alta. This was some dense stuff though, as tends to happen later in the season.

After that storm cycle, a high pressure system moved in, and now it’s sunny and quickly warming. Spring is definitely here in the valleys. The temperature has been flirting with 40°F in the upper Cottonwoods, and it’ll push 50°F over the next 2 days. Thankfully temperature doesn’t have much impact on snowmelt rates, at least it’s dwarfed by the impact of the sun. The sun is as strong now as it is in mid-September. The snow pack on the back side of the mountains is ripe, but the higher elevation still have time.

Snowpack temperature via NOAA
Snowpack temperature via NOAA

The next storm is Thursday. High clouds will start tomorrow, and their bases will lower going into Thursday. Right now it looks like the cold front will come through in the morning, and most of the precipitation will be with the front. The Cottonwoods are looking at 8-12″ of snow, and snow levels will be around 6000′. I’m somewhat worried about a dust storm coming before the cold front. Strong south winds will start overnight tonight, and the longer they blow the more dust gets in the air. However, we did just have a soaking storm, so hopefully the soil stays put.

Stay tuned for more details.

March Madness Powder

TLDR: The first of two Pacific storms is upon us and has dropped a decent amount of valley rain and mountain snow here in northern Utah, with more on the way. A second storm will pass through our region beginning Saturday evening, bringing in another chance for significant snow in the mountains.


Today’s Weather:

Snow has fallen once again in our beautiful Utah mountains after what seemed like a LIFETIME of the hot sun beating down on them, melting away quite a bit of a still-solid base depths. Snow totals across the area have been modest with Alta and Snowbird reporting ~4″, and everyone else a big goose egg.

Snow should pick up around 8PM tonight, however, with more valley rain and mountain snow. Bases of ski locations above ~6,500 ft should receive all snow (albeit very wet) as freezing levels will be around 7,500 ft and wet bulb zero temperatures will be ~6,600 ft.

GFS forecast sounding valid late tonight/early Friday morning showing a moist column of air with freezing levels ~770 hPa (7,500 ft). Courtesy: weathernerds.org
GFS forecast sounding valid late tonight/early Friday morning showing a moist column of air with freezing levels ~770 hPa (7,500 ft). Courtesy: weathernerds.org

Expected snow totals tonight should be the following:

  • Beaver Mountain: 1-3″
  • Snowbasin/PowMow: 2-4″
  • Park City Ski Area: 1-3″
  • Solitude/Brighton: 2-4″
  • Alta/Snowbird: 2-4″
  • Sundance: 1-2″
  • Brian Head: 1-3″

Friday and the Weekend:

As the upper-level trough currently affecting our region slowly moves eastward, expect  synoptic scale lift to continue providing valley rain/mountain snow showers across Utah. Ridging eventually will dry us out and put an end to showers by late Friday evening. Snow totals tomorrow look to be modest again, generally 2-4″ across the board in higher terrain. Take a look at the HRRR forecast precipitation type radar from today through Friday evening.

HRRR forecast rain/snow radar valid from this morning through tomorrow afternoon. Courtesy: weathernerds.org
HRRR forecast rain/snow radar valid from this morning through tomorrow afternoon. Green/yellow/orange/red indicate rain, pink indicates mixed precipitation, and blue represents snow.  Courtesy: weathernerds.org

Ridging will continue through the day on Saturday until the early evening with light snow showers beginning as our second Pacific storm moves in. At this point, it appears that there will be quite a bit of difference aloft, so some precipitation could be of the convective type. As of today’s 12Z ECMWF (Euro model), the forecast it for a combined 15″ of snow for the Cottonwoods from now through Sunday evening. We’ll see how it shakes out!

12Z ECMWF (Euro model) "Kuchera" snow total forecast showing upwards of a 1.5 feet of snow over the northern Wasatch mountains through Sunday afternoon. Courtesy: models.weatherbell.com
12Z ECMWF (Euro model) “Kuchera” snow total forecast showing upwards of a 1.5 feet of snow over the northern Wasatch mountains through Sunday afternoon. Courtesy: models.weatherbell.com

Extended Outlook:

In general, the pattern going forward looks to be quite moist. The GFS precipitable water (PWAT) forecast indicates that an “atmospheric river” could persist over the region for quite some time (at least a week). With the global models forecasting an overall “troughy” pattern for us, that means we might have the potential for some interesting winter storms yet before some of the ski locations start to close!

GFS forecast precipitable water (PWAT) anomalies valid from now through next Wednesday evening. Courtesy: tropicaltidbits.com
GFS forecast precipitable water (PWAT) anomalies valid from now through next Wednesday evening. Green and blue shading indicates greater than normal PWAT values. In general, there are quite a bit of modestly above average PWAT values forecasted to advect into our region over the next week. Courtesy: tropicaltidbits.com

Enjoy the new snow, and good luck to all of your NCAA brackets!

-Pete

Successive Spring Storms

Today marks the Vernal Equinox and the first day of astronomical spring (in contrast to meteorological spring -which started on March 1). It definitely has felt springlike as well, with sunny conditions and mild temperatures over the last several days. Active weather will return for the end of the week and looks to continue through the rest of the month of March.


As we have mentioned over the last couple of days, we have two storms on the horizon. The first will make its way into Utah tonight and Thursday. Visible satellite (below) shows cloudiness associated with this first storm progressing into Nevada and southwestern Utah this afternoon.

True-color satellite imagery from the College of DuPage this afternoon. Clouds and moisture are working their way into the continental US. Central and southern Utah will see rain and snow begin this afternoon and evening, while northern Utah will have to wait until Thursday morning.
True-color satellite imagery from the College of DuPage this afternoon. Clouds and moisture are working their way into the continental US. Central and southern Utah will see rain and snow begin this afternoon and evening, while northern Utah will have to wait until Thursday morning.

Central and southern Utah should see some decent snow totals from this first storm through Friday morning. Winter Weather Advisories are in place for the high terrain, where totals of 8-16″ are generally expected. Most lower elevations can expect rainy conditions as warm temperatures will limit accumulating snows to higher elevations above 6,500 – 7,000 ft.

Northern Utah won’t see quite as much precipitation, but it’ll be a nice refresh to the snowpack after many days of intense sun. Snow should begin for higher elevations after midnight tonight is likely continue mainly uninterrupted through the weekend. For the first round of snow in northern Utah from early Thursday morning through Friday night, it’s looking like 6-12″ for the Cottonwoods and 3-7″ for other resorts. Expect all rain along the I-15 corridor and the Wasatch Front (even the benches) through Friday night.


The next round of rain/snow after that looks as it if will move in from a more westerly direction and cross northern Utah from Saturday afternoon through midday Sunday. It also looks to be a bit cooler in comparison, so snow levels will be lower but at this time don’t appear like they will reach valley floors. We should be able to get decent amounts of snow for the high elevations with this storm as well, but we will get into the details of that in future posts as the week progresses.

Current model guidance and ensemble forecasts show temperatures rebounding for the first couple days of next week, but another storm has potential to head our way for the last days of March.

GEFS 12Z ensembles over the extended period showing temperatures (top lines) and precipitation (bottom lines). Our next two storms are visible in the precipitation ensemble members, followed by what is looking to be a brief warm up before storminess returns for the last days of March. (wetterzentrale.de)
GEFS 12Z ensembles over the extended period showing temperatures (top lines) and precipitation (bottom lines). Our next two storms are visible in the precipitation ensemble members around March 22 and March 24, followed by what is looking to be a brief warm up before storminess returns for the last days of March. (wetterzentrale.de)

 

-Lucas

Spring Powder Underway Late-Week

TLDR: Spring is here, but the powder won’t run dry for a while. Two storms will bring moderate precipitation over northern UT resorts and substantial snowfall to southern UT resorts. Scroll down for a summarized snowfall forecast.


I headed up-canyon this morning and eventually stumbled through a few substantial corn stashes. Spring has arrived.

spring
Honeycomb Canyon, Solitude Mountain Resort, 11 AM March 19, 2019. PC: @marcelsiuss (Instagram)

Of course, we’re also under a particular weather feature that keeps the sun out over the slopes. Combined with the high spring sun, that will keep even the somewhat north-facing snowpack in a melt-freeze diurnal cycle.

Early-Week Meteorology

This weather feature consists of a stretching deformation in the wind flow above Utah. To explain, deformation describes how objects would be affected by the flow in some large area. In this stretching deformation, an object like random cloudiness would be stretched apart by the wind flow before it could organize and establish itself. The result: blue skies, calm weather, lots of sunshine.

spring
12Z GFS 500 mbar absolute vorticity (shaded) and wind barbs, valid 6 PM MT Tuesday, March 19, 2019. Annotated in black are mid-level wind flow and expected weather conditions, in green is the leading edge of a Pacific Low that will affect parts of the western US through the week, in red is the location of Salt Lake City UT. The wind flow over UT resembles a pure stretching deformation; you might imagine putting a square in there and watching it stretch along the NW-SE line according to the wind flow. This deformation prevents weak weather features from maintaining their structure, leading to clear skies and calm winds. Courtesy tropicaltidbits.com

By the grace of high elevation, we’d expect the snow potential at most resorts to continue late into spring. In fact, we’ve been hinting toward at least two storms to hit parts of Utah in other posts. Overall, we seem to remain moderately active in the foreseeable future, which will also contain a few inactive periods similar to this week. With that, I’m now going to focus in on two back-to-back storms that will impact the area between Wednesday and Sunday nights.


Late-Week and Weekend Forecast

Temperatures this week are just about average for this time of year across the western US. This means that snow levels are on average up to middle- and upper-elevations in the Wasatch, upper-elevations in Southern Utah. Therefore, you can expect that lower parts of lower-elevation resorts won’t see much snow this week.

Storm One: Wednesday night – Friday night

First, a late-week system will hit hard over southern portions of the western US, putting resorts like Brian Head and Eagle Point in the position to receive over a foot of snow. Northern resorts will catch the periphery of this storm and receive moderate snowfall by Friday evening. I summarize these in the graph below.

Note: We’re working on interpolating downscaling model forecasts to Brian Head and Eagle Point resorts, so I did not include confidence intervals for snowfall at those locations. However, those skiers can expect about 1.5″ of snow-water equivalent, give or take, and with maybe an average of 11 snow-liquid ratio, I’d say 12-18″ is a good snowfall forecast for this storm. 

spring
Subjective snowfall forecast for Utah resorts thru 5 PM MT Friday 3/22/2019. These are primarily from both GEFS and CMCE members of the NAEFS.
Storm 2: Saturday night – Sunday night

A second system will track farther north and will be weaker than the first. Temperatures should be similarly on-average for this time of year, but this storm is a bit more complex and uncertain than the last. Therefore, I’m unable to provide a forecast that I’m confident will be accurate.

For fun, my initial educated guess would be 1-3″ at lower-elevations and 3-6″ at higher elevations*. Perhaps more locally.

*These are from SREF and NAEFS QSFs


Check back tomorrow for final comments on the storm 1 forecast, then later for details about storm 2. This should be a fun weekend for skiers.

Cheers,

-Marcel

Some Storms on Horizon

TLDR:  Sunny and warm on Tue then clouds on Wed.  A storm will favor southern UT on Thu and provide some snow Thu-Fri in northern UT.  Then a relatively quick storm favoring northern UT Sat-Sun.

Next Couple Days:  Tuesday will be sunny and slightly warmer.  As a storm approaches Wed we’ll start to see some afternoon clouds with continued warmth.

Mid-Range:  A low-pressure system will move into southwest UT on Thu with likely 5-10” for Brian Head and Eagle Point.  The same low will impact northern UT late Thu into Fri but current forecasts have the center of the low staying south and northern UT on the periphery.  The locations of precipitation bands on the periphery of closed or nearly closed lows are notoriously hard to pinpoint, so some areas might get 4-8” while others get 2-4”.  Check back as we get closer.

Long-Range:  A relatively fast moving but better organized cold front and precipitation band are forecast for much of the state Sat afternoon through midday Sun.  The precipitation will favor northern UT but will be short lived and I’m not expecting huge accumulations.  Below is an ensemble probability of places seeing > 1” of precip over the next 7 days…which would amount to roughly 10-12” of snow.   Decent odds, but I’d like to see it higher.  Click on the “figure” for a bigger version.

-Tyler

figure

NAEFS 7-Day Probability of Precipitation Greater Than 1". Valid 18 Mar 12Z. http://weather.utah.edu/index.php?runcode=2019031812&t=naefs&d=PP&r=UT
NAEFS 7-Day Probability of Precipitation Greater Than 1″. Valid 18 Mar 12Z. http://weather.utah.edu/index.php?runcode=2019031812&t=naefs&d=PP&r=UT

Few More Days of Dry

We’ve been enjoying dry and sunny weather over the last few days. An area of high pressure has been keeping storms away from western North America, and there aren’t any major storms anywhere in the lower 48 today. It’s also been keeping pollution trapped in the valley. It’s late enough in the year that ozone is starting to be a problem, and there’s the perennial particulate problem as well. The DEQ is predicting moderate air quality for the next few days.

GOES-16 Imagery via CIRA
GOES-16 Imagery via CIRA

Even with the sun this weekend, there’s a remarkable low-level snowpack. The last good winter we had (2017) was characterized by a lot of warm storms with tropical moisture, and that really kept low-level snowpack minimal. This year we only had a handful of those warm storms, so the snow has been spread evenly across the elevations. The current map of snow water equivalent at measurement sites shows the uniformity across northern Utah.

Snow water equivalent via USDA
Snow water equivalent via USDA

The green colors in the map above show snow water equivalents between 125% and 175% of median. Virtually every site in northern Utah save a handful on the north slope of the Uintas and near Bear Lake is in that range. What this means is that there is snow in the central Wasatch nearly all the way to the valley floors on the north aspects. Also it means we’re looking very healthy for our water this year. Most of Utah is officially drought-free except for the Bear River watershed where snowfall has been at or slightly below average. However, water managers are being cautious considering last year was the driest on record, so most of the state is considered “abnormally dry”.

Now the weather. There will be a bunch of clouds passing through on Monday, but the sun will be back Tuesday. Then the ridge will start shifting to a trough, and the snows will return. The first storm of the next cycle will be Wednesday night into Thursday. This will focus more on southern Utah with less falling in the Wasatch. Beyond Thursday there will be several small storms that impact northern Utah. Of course, this is far enough out that the details are variable. Stay tuned for updates.

ITS DEEP

Its March in Utah and the skiing just keeps getting better.

Lets take a minute to appreciate the fact that over the last 48 hours, Alta has gotten 38″ of new snow.  Yes, you heard that correctly, OVER THREE FEET IN TWO DAYS.  Snow report below brought to you by Onthesnow.com

Screen Shot 2019-03-14 at 4.51.50 PM

 

The rest of the state isn’t doing so bad either.  The snow has been frequent and abundant this winter and I don’t think anyone is upset about it… Well expect the poor guys who have to plow the canyons.  We should all write them thank you notes at the end of the season.

Here’s a quick basin-filled map showing just how great this year has been.  We’re well above normal across the board for snow water equivalent

Utah basin-filled snow water equivalent map courtesy of www.wcc.nrcs.usda.gov
Utah basin-filled snow water equivalent map courtesy of www.wcc.nrcs.usda.gov

 

Expect quiet weather through the weekend as a ridge builds in over the intermountain west.

GFS 500 mb heights valid Sunday 12am. Forecast graphic courtesy of tropicaltidbits.com
GFS 500 mb heights valid Sunday 12am. Forecast graphic courtesy of tropicaltidbits.com

For now, enjoy the pow!

-Taylor

Enjoy the last storm for awhile!

Today has been snowy and cold with quite a bit of wind out there too! Many ski locations have received a foot or more of snow over the last 12+ hours as of this afternoon, with more on the way. Not too many crowds today at most resorts, though, as the wind and low visibility (and work/school day?) have kept a lot of folks home.

View from Snowbasin Resort this afternoon. Heavy snow with low visibility and very strong winds. Courtesy: snowbasin.com
View from Snowbasin Resort at John Paul Lodge this afternoon. Heavy snow with low visibility and very strong winds has been the case all day so far. Courtesy: snowbasin.com
Time chart of winds at the top of Snowbasin Resort's Strawberry lift. Very strong winds and wind gusts are evident throughout the day. Courtesy: mesowest.utah.edu
Time chart of winds at the top of Snowbasin Resort’s Strawberry lift. Very strong winds and wind gusts up to ~45 mph have been evident throughout the day. Courtesy: mesowest.utah.edu

Tonight will bring additional snow to the mountains and valleys as a cold pool settles in at mid levels. We can expect an additional 1-3+ inches in the far northern Utah ski locations and in Park City. In the Cottonwoods, there could be another 4-8+ inches overnight. The very strong winds should be letting up quite a bit overnight. Heavier snow activity should tapper off by ~5-6 AM overnight, but intermittent snow showers will continue into through the day on Thursday. Even with the very strong winds dying down overnight, though, it will still be VERY cold during the day tomorrow with wind chills forecast to be in the -5 to -10 degrees Fahrenheit range in many ski locations. Bundle up!

Enjoy this storm while it lasts, though, because it looks like it could be the last one for awhile (perhaps until late next week). As Lucas mentioned yesterday, it will be sunny, warm and dry for the next several days. Below is a forecast 500 mb vorticity animation showing a large ridge of high pressure building in from south of the Gulf of Alaska into the West and Intermountain West over the next week. Some models are showing a potential system for next Thursday, but my confidence in that is low at this point since it is simply too far out.

GFS forecast 500 mb vorticity from today through next Wednesday. A large ridge of high pressure will build in over the area from south of the Gulf of Alaska, giving us warm, sunny days for quite awhile. Courtesy: weathernerds.org
GFS forecast 500 mb vorticity from today through next Wednesday. A large ridge of high pressure will build in over the area from south of the Gulf of Alaska, giving us warm, sunny days for quite awhile. Courtesy: weathernerds.org

Enjoy all that powder the rest of today and tomorrow, and be safe getting up and down those canyons!

-Pete

Snowy then Warmer and Drier

After a couple days of warmer temperatures and clearer skies since the stormy weekend, we will transition back to winter for the middle of the week as a cold storm system impacts the Intermountain West. After that, we will return to milder weather for the weekend.


Midweek storm (Tuesday evening – Thursday morning)

A closed low pressure system centered near the CA-AZ border spread some mid-level and high-level clouds into Northern Utah this morning and afternoon. Meanwhile, the next system that will bring us precipitation overnight tonight and into Wednesday has started to enter the Great Basin from the northwest. The two systems mentioned above will combine over the next few days to the east of the Rockies and rapidly intensify to produce a strong spring storm with severe weather, blizzard conditions, and flooding. Luckily for us, our main impacts will be from the storm with the more northerly track and we will get a nice snow event out of it!

GOES True Color satellite imagery from College of Dupage site shows several features across the western U.S. First, a low pressure system ejecting clouds northward into the southern Rockies, and second, a colder system entering the Great Basin region in northwest Nevada. (https://weather.cod.edu/satrad/exper)
GOES True Color satellite imagery from College of DuPage site shows several features across the western U.S. First, a low pressure system ejecting clouds northward into the southern Rockies, and second, a colder system entering the Great Basin region in northwest Nevada. (https://weather.cod.edu/satrad/exper)

The system entering the Great Basin will migrate eastward throughout the afternoon and evening, with mountain snow starting later this afternoon ahead of the main band of clouds and precipitation. In the overnight hours, a cold front will swing through Northern Utah and drop snow levels to the valley floors. Snowfall is expected throughout much of Wednesday for lower elevations, while orographic snowfall under northwest flow could continue for the mountains into Thursday morning.  By Thursday afternoon much drier air will move into the region to shut off any remaining showers. Sunny, calm, and mild conditions will persist through at least the weekend.

12Z GFS time-height section from weather.utah.edu for the next several days. Expect accumulating snow tonight and Wednesday as a cold and moist system moves in from the NW, lingering snow showers into Thursday (especially in the mountains), followed by warming, clearing, and drying conditions into the weekend.
12Z GFS time-height section (increasing time is to the left) from weather.utah.edu for the next several days. Expect accumulating snow tonight and Wednesday as a cold and moist system moves in from the NW, lingering snow showers into Thursday (especially in the mountains with NW flow), followed by warming, clearing, and drying conditions into the weekend.

Winter Weather Advisories are in effect for the Wasatch Mountains and Wasatch Front south of Interstate 80 through Thursday morning. Road conditions will not be great across much of the area tomorrow but skiing should be excellent (also chilly and breezy) with fluffy powder and some free refills throughout the day!

Expected Snowfall through Wednesday:

  • Cottonwoods: 8-16″
  • Park City Resorts and Powder Mtn: 5- 10″
  • Sundance & Snowbasin: 3-6″
  • Wasatch Front (SLC southward): 2-6″ with locally higher amounts for east benches possible

Some areas could have continued snow showers into Thursday, which would mean there is possibility for another powder day – especially if the moist NW flow keeps up!


As mentioned above and visible in the time-heigh section, milder conditions are expected into the weekend and beyond. GEFS Ensembles below also show a continued period of warming with dry conditions for the next ~10 days. After that, another active weather period looks like it may be on the horizon for the end of March, but it’s too far out to know much with any certainty.

GEFS Ensembles from wetterzentrale.de showing our cold storm for Wednesday, followed by several drier days with a warming trend. Another active weather period is possible around March 22 and beyond.
GEFS Ensembles from wetterzentrale.de showing our cold storm for Wednesday, followed by several drier days with a warming trend. Another active weather period is possible around March 22 and beyond. Upper lines and lower lines are temperatures and precipitation, respectively,  for different ensemble members. 

Enjoy the fresh snow tomorrow and Thursday, and pack your sunscreen if you head to the mountains this weekend!

-Lucas

 

Probability of Powder: The Long and Short Term

TLDR: A mild air mass will give way to cold polar air and a moderate powder drop Tuesday night. Scroll down for an initial snowfall probability forecast.


One-Month Probability Forecast

It seems out of the norm that a series of big powder dumps isn’t in the extended forecast. One storm this week will be followed by a period of low chances for a powder day. The next month, however, may favor wetter-than-normal precipitation according to NOAA’s CPC climate outlook:

probability
The Climate Prediction Center’s one-month outlook for the probability of anomalous precipitation. Shaded are probabilities for above- (green) and below- (orange) normal precipitation during the next month. Darker shading expresses a higher probability. These figures are often misinterpreted because they appear to show where it will be wettest and where it will be driest, but that’s incorrect. Areas shaded in green may see below-average precipitation over the one-month period. So this figure should be used to place your bets as to which areas will receive above- or below-average precipitation. However, you’re given no information as to how far above- or below-average the precipitation is likely to be. Courtesy the NOAA Climate Prediction Center at www.cpc.ncep.noaa.gov

Though from my experience these outlooks tend to provide less useful information than we ever expect. In this case, there’s about a 60% chance that the SLC area will receive more precipitation than is normal for the next month—a 40% probability for equal-to- or below-average precipitation—according to climate models. These aren’t incredible odds if you ask me.


This Week

Looking at the more reliable short-term forecast, we see one big system heading toward the interior west as the week carries on.

500 mbar prog
12Z GFS 500 mbar absolute vorticity (shaded), valid 6 AM MT Monday 3/11 to 6 AM MT Thursday 3/14. This “500 mbar prog” is useful for making a quick analysis of the short- and mid-range forecast state of the atmosphere. Courtesy tropicaltidbits.com

Daytime temperatures at ski resorts begin relatively mild (around or just below freezing) through Tuesday night. Some instability today (Monday) and Tuesday may allow light snow showers or overcast to exist at high elevations.

The mild early-week air mass will give way to cold polar air in time for the next powder drop. A moderate snowstorm Tuesday night will usher in unseasonably cold air that will remain over a few days.

You can expect a period of heavy precipitation with the arrival of a cold front Tuesday morning, but altogether this is a quick-hitter. This storm should drop a nice layer of fresh powder overnight for the mid-week crowd, and then another thin coating throughout the daytime.


Snowfall Forecast

The snowfall forecast is still uncertain. Here’s mine, just to give you a sense of the range of possibilities for this event at Utah resorts.

probability forecast
Subjective probability forecast for snowfall during the mid-week storm. Note, most importantly, the range of possibilities for each forecast. These are based on a combination of model ensembles, primarily the GEFS.

So still some uncertainty heading into the next storm, and then quite a bit more uncertainty reserved for next week. My suggestion is that you brace for a cold powder day Wednesday, then hold your dice until late this week when the day 5+ forecast may become clearer.

-Marcel