Can you call them storms?

Over the next 5 days Utah will primarily be on the downstream side of ridge that is going to set up camp over the Pacific coast.  This will put us in gererally westerly or northwesterly flow.  Current model runs have 3 distinct but weak shortwave troughs rippling along the top of the ridge.  Matt L. mentioned two of them yesterday (Friday night, Sunday) and there is currently a third on Monday.  I hesitate to even call them storms, but each will bring the possibility of light snow.  As is often the case with weak systems the details may change, but it is unlikely that any big dumps are gonna happen in the next several days.  Things also look fairly dry beyond Monday. Even the long-range Euro ensemble is producing next to nothing over the next week, so you know its bad.

Ensembles in weather modeling are many different runs of the same model that are each tweaked slightly at the beginning.  Looking at how different each of these model runs is from one another helps give an idea of the uncertainty in a particular situation.  For instance, the surprise dump on Monday was only picked up by a few of the ensemble members, leaving us forecasters to doubt the likelihood of it happening.  But the potential was there, and we just happened to realize it.  A good time to be wrong.

For some actual snowfall numbers, I am thinking 3-6 inches for Snowbasin, PowMow and Beaver by Saturday morning.  2-4 inches in the Cottonwoods, and 1-3 elsewhere.  The Sunday system might add another inch or two.  Too much uncertainty to put number after that, but its mostly dry.  Valley inversions shouldn’t be too bad, though.

If you are jonesing for pow think about heading north to Jackson.  Whenever we are just getting brush-bys to the north it is not uncommon for Jackson to be piling up the snow.  They might be having the best snow year in the United States so far, although snow totals in the Upper Cottonwoods aren’t too far behind.  Right now the snowpack in the mid and upper elevations of the Wasatch is pretty close to average for the date. 

 

A Pretty Nice Storm

With snow winding down in the mountains (but not completely over), here is  a look at how a few folks fared from this storm:

Alta: 19″

Brighton: 16″

Canyons: 15″

Ben Lomond (Northern Wasatch): 6″

 

So it was a pretty impressive event, especially when you consider the fact that most of this snow fell in about 10 hours. As I mentioned in my previous post, there were some very heavy snowfall rates during the day today. Not too bad for a storm that looked mediocre in Saturday’s compuer model runs…as I said, if our forecast is gonna bust, I’m glad when it busts on the high side.

Suffice to say, the skiing is going to be quite good at the PC resorts and in the Cottonwoods tomorrow. Snow showers will taper off through the day, with additional light accumulations. Temperatures will be comfortable, and winds will be light. Then for the rest of the week, the dreaded ridge returns. This means warm temperatures in the mountains, and inversions in the valleys.

Long Term: there is a lot of uncertainty in the models after Saturday. The GFS and Euro have trended toward not giving us a storm in the early-week timeframe, but this doesn’t mean much at this point. I have faith that we’ll get something during that period.

Nuketown

In the social media world these days, some of the ski areas like to throw around the hashtag “#nuketown”. I’ve been in some pretty incredible snowfall rates in my day, so I try to save hyperbolic statements like “it’s NUKING out there” for times when it is truly snowing as hard as it can possibly snow.

This morning, however, it has truly been NUKING in the Upper Cottonwoods.

Our University of Utah Department of Atmospheric Science site in Albion Basin recorded 3-4″ of snow in ONE HOUR! Storm total now sits at 9″.

So the question then becomes: how badly is my forecast of 7-14″ for the Cottonwoods going to bust? With this much snow having fallen already, we won’t need much more to get past 14″.

A storm total of 14-20″ seems more reasonable, with 10-14″ for the PC side. The forecast for the Northern Wasatch still seems on track.

Sorry about the forecast bust, but hopefully no one is complaining about extra snow!

Storm Update

The forecast is still largely on track, but I’m gonna go ahead and bump up Ian’s numbers. As the resident pesimist at USW, Ian likes to keep it a bit low (I guess it is better to have storms exceed your expectations, than vice-versa), but I really have felt good about the model solutions for most of the day today.

The timing of heaviest snow still looks to be tomorrow late morning through late evening, with snow tapering off by Tuesday morning. I expect 7-14″ for the Cottonwoods, with 6-12″ for the Northern Wasatch, and 5-10″ on the PC side.

So it looks like the skiing should be decent on Tuesday morning IF the forecast verifies on the high side of our numbers…I think 7″ on the current hardpack wouldn’t be quite enough for powder day type conditions. The snow will be of moderate density though, so this should help keep your skis off the bottom better than low density powder. Winds also look to be relatively light, so this will make for good skiing.

Long Term: another ridge settles in after this storm, with warm mountain temps and valley inversions. The good news though, is that it looks like a storm is in the works for the upcoming weekend.

Mediocre or bad? That is the question

Well, here’s the deal.  We have a couple sad excuses for troughs moving through Utah between Sunday and Tuesday.  The heat, sun and wind have taken their toll on the snow and conditions are about as bad as Utah gets this time of year.  Whether you believe the GFS or Euro model depends on whether we will get an upgrade to mediocre conditions by Tuesday or we will simply stay at bad.  But we can’t complain too much, we could live on the East Coast. 

The GFS is currently really dry over the Wasatch, with only 2-4 inches forecast by Tuesday.  If the juiciest band in the GFS shifts over the Wasatch, make that 3-6. Southern Utah will do better.

The EC ensemble is looking a little better with more like 3-6 possible by Tuesday, with the most optimistic members maybe getting to 10 inches.  I know, its depressing.  Overall the expectations are down a little from what Matt forecasted yesterday. The forcing for precipitation in these troughs will be more dynamic than orographic, so there may not be huge biases from one resort to another.  Due to uncertainty with what will happen, I am not even going to bother with resort specific amounts except to say that whatever falls definitely won’t come before Sunday morning.  Sunday could be a real bad day if clouds keep the sun at bay and all the ice just stays ice without much new snow falling.  During the day Monday looks the most likely to see snow. 

The long term still looks depressing with another big ridge next week.

The Heat is On

With the partial mix-out of the valley cold pools yesterday, loss of some snow cover, and an exceptionally warm upper-level airmass working into Utah, we have actually managed some pretty warm temperatures in the valley for a January inversion episode. The WBB weather station at the U currently sits at 51 degrees…pretty impressive. Unfortunately, this means that the heat is also on in the mountains. Alta-Collins is at 37 F, and the bases of the PC resorts are in the mid 40s.

As promised, a strong upper-level ridge has been building over the intermountain West, and it will continue to strengthen its grip on us through tomorrow. Today has been very warm, but tomorrow will be pretty exceptional. As Trey mentioned, the 700mb temperature will likely exceed 6 C…this is just about as warm as it can possibly get in the Wasatch in January, As a result, we’ll likely see mid to upper 40s at most resorts, and the south-facing slopes are going to get cooked. Wet-loose avalanches are also going to be running on these aspects. One bright spot to this heat wave is that it is early January, and the sun angle is low enough that the snow on high-elevation north-facing slopes may remain relatively intact if we remain cloud-free and the humidity is low enough.

Thankfully, the ridge starts to flatten after Wedsnesday, bringing a slow cooldown through the weekend. The EC and GFS are also bringing a storm through Utah early next week, but there is some uncertainty as to the quality of the storm. At this point though, a cooldown and fresh snow are more than enough to make me happy.

 

If you want Powder go north

Unfortunately the Wasatch missed out on some big-time snow by just a few hundred miles. If you want some fresh snow go up towards Jackson Hole and points north into Montana..they’ve gotten hammered the past couple days! Meanwhile, we haven’t seen much down here in Utah and things don’t look like they’re in a hurry to change any time soon. 

Strong ridging will move overhead mid-week with warm spring-like conditions in the mountains and strong inversions in valley locations. 700 mb temperatures will reach 6 degrees Celsius by Wednesday which is very warm for this time of year. Resorts will probably top out in the mid-upper 40s!!  Things begin to cool down a little by the end of the week as the ridge axis moves away, but it still remains entrenched enough to void the area of any significant storms. A couple weak systems may impact parts of Utah this weekened into early next week but I don’t see anything of any significance for the next 7 days.

Bring a beach chair

Unfortunately the most significant news I have to rely from the forecast for this next week is extreme warmth.  Wednesday in particular will be an awesome day to get a head start on your spring break tan up at the resorts with temperatures in the 40’s.  The valley air will grow dingier and dingier as well.  This is a classic inversion pattern, with a big ridge building over the West.  Thankfully the low sun angles will preserve the snow on the high north faces, but icy or slushy snow will be widespread elsewhere this upcoming week.

Sunday and Monday we will get brushed by the strong NW flow that will deliver quite a bit of snow to the Jackson area.  So head there if you want to ski powder this week.  In the central Wasatch this system will amount to just some flurries and clouds.  Beaver and other areas north have a chance of recording an inch or two. 

In the long range, the GFS has been hinting at a trough for next weekend, but the details are never consistent from run-to-run so confidence is low.

Thawing Out

Last night and today were a great example of a process in the atmosphere that we meteorologists refer to as “advection.” When the sun set yesterday evening, the temperature quickly plunged to -2 Fahrenheit at the Alta-Collins obsevring site. Instead of dropping further, however, the temperature actually rose throughout the night, reaching a balmy +7 Fahrenheit by 7am. This was the result of warm air being transported by the upper level winds into Utah. Pretty amazing to have the temperature increase on a clear december night, and an example of one of the many challenges in weather forecasting…the temperature doesn’t necessarily drop overnight!

Anyway, what does this mean for your weather forecast in the Wasatch? Well, the cold air we have sitting in the snow covered valleys isn’t going anywhere, so the warming air overhead means that inversions will set up in the valleys, with temps warming in the mountains through Friday under partly-mostly sunny skies. This should make for great skiing weather!

I know I know, most of you want the snow to come back though. So do I, but the outlook is not terribly encouraging. I think we’ll see some light snow (and a brief return of colder temeratures) on Saturday as a shortwave trough over Wyoming passes by us, but as Trey mentioned, doesn’t look like much of an event for the Wasatch. And it will be short-lived.

Long Term: After Saturday, things look to get quite warm in the mountains unfortunately. Not great for the snow on south facing slopes, and not great for air quality and temperatures in the valleys, which will be cold under stout inversions. All model guidance points to a pretty strong ridge sitting over us through at least mid-week, BUT I do see reason to hope for the late-week timeframe…until then, enjoy the sunshine. We were pretty spoiled by this last storm cycle, and you’ve gotta have a break here and there. Get your work done around the house so you can be ready for the next one.

Have a safe and happy New Year!

A Break in the Action

Unfortunately, the active storm pattern we’ve seen the last couple weeks has come to an end. It’s been a remarkable run with the snowpack doubling in just the past 2 weeks! The storm cycle stacked up perfectly beginning with a dense Atmospheric River event followed by progressively less dense snow, and ending with an incredible 4% in the final burst. Hope everyone was able to get out and enjoy it! I’ve been out of town and my arrival has brought an end to the active storm cycle (don’t worry, though, I’ll be gone again in 10 days and with that I’m sure things will get active again 😉 ).

A quick rundown of what to expect for the next week: Temperatures in the mountains will progressively warm to near climatology norms by the end of the week. This warming will occur as strong upper level ridging moves overhead. And you all know what that means for the valleys this time of year especially with a snowpack: Inversions! We could get a little something from a shortwave trough this weekend but the models currently keep it north of the Wasatch (though the ECMWF is slightly more amplified/farther south). At the very least hopefully this will help mix out valley inversions some. We’ll continue to keep an eye on this feature but it doesn’t look to be of anything significant attm. Beyond the weekend it doesn’t look like anything noteworthy until maybe mid-week at the earliest.