Storm Timetable

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!

 

Things are trending the right direction…

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. 

 

 

 

On the Edge

Wow, hopefully all of you powder lovers had a great weekend out there. The storm is long gone today, but I am definitely still grinning about the great turns I had at Alta and Snowbird this weekend. Temperatures are beginning to warm, and will continue to do so under a weak ridge through Wednesday under sunny skies. Although as Trey mentioned, even this “warmup” will still feel chilly after the April-like temperatures we’ve gotten used to.

We are still on track for a storm Thursday/Friday, followed quickly by another shot over the weekend.

The first storm (shortwave trough) will be modest, but the cold temperatures aloft and light NW flow will be working in its favor. Don’t expect a big powder day, but it should be a nice refresher. We should be close enough to the event tomorrow for Jeff to give you some snowfall numbers.

For the weekend storm, the models continue to depict the strongest ascent and snowfall further south, putting the Wasatch on the northern edge of the best action. This is especially true of the ECMWF, which mainly hammers southern Utah/northern Arizona. Hope still remains, however, as there are many ensemble members that depict things far enough north to bring a big dump to the Wasatch. 

So in other words, the weekend still looks to be boom or bust as far as snowfall is concerned. My only hope as a forecaster is that the models do not continue to put us right on the edge of a big snowfall/small snowfall boundary as we get closer to the event…no one likes being teased by the atmosphere.

 

More Snow! But how much??

Looks like we’ll be staying in a fairly cold, more winter-like pattern at least through next week. We’ll warm up slightly Tuesday/Wednesday, but compared to what it’s been the past month it’ll probably still seem cold. On to the good stuff and what we’ve been waiting a month+ for. The pattern change is HERE! High amplitude ridging which has dominated the Western U.S. and plagued Utah for most of the past month will shift westward. This will help open the door for a period of active northwesterly flow with numerous storms affecting the Western U.S. How exactly this pans out for Utah remains to be seen, but I can almost guarantee we’ll have more snow days and better odds at decent accumulations through the next couple weeks than we’ve seen in a while.

The first potential storm to impact us will begin to move into the picture Thursday. Precipitable Water (a measure of moisture) values will begin to increase in advace of the first of a series of shortwave troughs embedded in NW’ly flow. The evolution of this first shortwave will have important implications in determining how the longwave trough and other shortwaves evolve. Without getting too much into the details the latest GFS and European runs have been trending towards and are now showing a deeper overall longwave trough by next weekend. While Northern Utah would still almost certainly see snow from this type of evolution, the best moisture and dynamics would be shunted off farther towards the south. The 00z European run (yesterday) and some ensembles, however, were farther north with the best dynamics and the overall evolution. These different model solutions we’re seeing right now could mean the difference between a mediocre 6 inch storm and a blower 1-2 foot + storm. In summary, the jury is still out on how this will pan out so let’s hope models trend back towards a more northerly solution. Regardless, though, snow is in the forecast for a change. Oh and one more tidbit… things are looking good even beyond this system, so if it doesn’t nail us maybe the next will.

A couple inches so far…

A brief snowband moved through the central Wasatch this morning and put a quick 2-4 inches of relatively light snow on the ground.  Between Friday afternoon and Saturday afternoon all areas will pick up another 2-4 inches.  Beaver might get 3-6. Scattered showers Sunday could add up to an inch.  

This trough is a pretty funky one, as previous posts have said.  The trough is oriented west-east instead of north-south.  And we are really just seeing the peripheral scraps.  The northeasterly flow that results from such a pattern isn’t good for orographic enhancement over the Wasatch either.  As the trough elongates on Sunday and Monday Colorado and Southern Utah will be under a relatively stationary snowband that could produce up to 2 feet of snow.  Head to Silverton Moiuntain if you want deep powder this weekend.  Unfortunately, Northern Utah will be just a little too far to the north for this band.  

Looking out further in time, it definitely looks like we have seen the last of the 60 degree weather for a while.  Even though a ridge rebuilds after the trough this weekend, its looks like things are a-changin’.  The ECMWF ensemble mean (an average of many model runs) is keying in on a shift from ridging over Utah to troughing late next week.  Now, being under a mean trough doesn’t necessarily mean you are going to get big storms, but it is certainly a good sign.  While things look relatively dry over us from Monday-Thursday, we do have reason to hope.  

For the real optimists out there, the current GFS run has a real big storm for next weekend.  Let us hope that it doesn’t disappear into the model ether.

Pattern Change?

Although not totally certain yet, things are looking better and better for us to FINALLY break out of this dry pattern that has been plaguing us for the past month. Assuming the GFS and ECMWF ensemble members are capturing the full range of possible conditions (sometimes not a safe assumption), we will see a shift to a much cooler and stormier pattern beginning with a storm this weekend. I am not completely sold yet, but I like what I see from the models so far.

Wednesday/Thursday: we will be warm (once again) through Thursday, with sunny skies and light-moderate winds prevailing.

Weekend: a shortwave trough will slide in from the NW beginning late Friday, bringing clouds, a cooldown, and some snowfall to the mountains. As for snowfall amounts, I’m not expecting a dump or anything, but we’ll see how the models trend over the next few runs. The storm may linger over us through Sunday or even Monday, so it would at least have time on its side to drop some snow.

Next Week: forecasting this far out is often a bit of a stretch, but I know what the people want! So I will say that after a brief warmup/dry out early week, there is a shot at another storm late week. Woo! Keep those fingers crossed.

 

A New Hope

The past 4 weeks are about as bad as it can get for snow in Utah this time of year… It looks like that will continue at least until the end of the week. Fortunately, the Cottonwoods have a “solid” base so essentially it’s been spring skiing but with a lesser base than you’d normaly expect. I guess that’s better than cold bullet proof skiing with no new snow, right?! The spring skiing continues mid-week after the brief cooldown we’re seeing currently. To put things in perspective, on Thursday Salt Lake City has a chance to have a LOWER high temperature than Miami, Florida. How often can you say that during the heart of winter?!? All isn’t lost, though, and we have a new hope!

By late week ALL models are suggesting that the stronghold ridging for the past 4 weeks will retrograde westward and a strong shortwave trough will dive into the Pacific NW. The degree of exactly how this storm system evolves remains very uncertain. The EC, GFS, Canadian, and their associated Ensembles all show very different evolutions. There are 2 main players to look for in the coming days that will influence the magnitude of the storm: The positioning of the west coast ridging and the degree that the southern stream jet interacts with this shortwave trough. Right now the EC shows a much “broader” longwave trough yielding .4 – .5 inches of SWE. The EC ensembles, however, show even much lower amounts, indicative of the high uncertainty with this upcoming storm. The latest GFS run, on the other hand, nukes us with a slow moving and sharper trough axis (with multiple shortwaves) that evenutally closes off into an upper level low..this yields > 1 inch of SWE. The GFS ensembles show lower precipitation amounts.

Bottom line: These are some of the most interesting model solutions I’ve seen in quite some time. Uncertainty remains HIGH, though, with large spread in the ensembles and run to run variability. Hopefully we can start pinpointing things down in the next couple days and thing will trend upwards.

A Warmup and a Cooldown

As Trey mentioned, the models are now starting to lock onto a big cooldown for early next week…with the potential for some snow. Still can’t make a reliable forecast this far out, but it’s something to keep an eye on. 

Until then, the forecast is still on track for a big warmup as we progress through the week. Each day (beginning today) will be warmer than the previous, and Friday will be the warmest day. With sunny skies and light winds on tap, Thursday and Friday will likely be the best days to ski. Temps will begin cooling on Saturday, so the crusts will become slower to soften as the weekend progresses, although the cooldown doesn’t really gain steam until Sunday. Clouds will also start to thicken on Sunday ahead of the approaching system I mentioned that will be coming into the picture for early next week (if you’re looking for these kinds of specific details for planning your ski day, remember to check out our “Resort Forecasts”). 

The temperatures for early next week will be quite a shock for those of us who have become accustomed to the late-April weather we’ve been having. So enjoy the warm weather for the next few days. 

Nothing New

Wednesday Update: Yesterday I mentioned there was a high amount of variability in the models beyond the weekend. The latest 12z models have continued to show colder weather moving back into the area. Different from earlier model runs, however, the operational GFS and ECMWF are beginning to show more substantial threats of precipitation. I’m not completely sold yet since it’s 5+ days out and the ensembles are still all over the place. But one thing is looking more certain, a MUCH COLDER airmass will move into the region with 700 mb temps progged near -15 C.

Old update continues below:

This post will be short and not very sweet. Warm conditions will return to the Wasatch through this next weekend as ridging builds back in behinds this latest “weak storm”…if you want to call it that. Looks like spring skiing conditions with highs in the upper 40s to lower 50s in the mountains. South facing aspects will start to really get baked this weekend. As we get farther from the winter solstice and nearer to the spring equinox, the sun angle continues to get higher and the days longer. These prolonged periods of no snow haven’t really been detrimental yet to the overall snowpack, BUT if this continues the next few weeks I think we’ll really start to notice a depletion. Let’s hope it doesn’t come to that.

Early next week we may get some relief from the heat, but unfortunately it looks like a mostly “dry front”. There is a high amount of variability, though, in the ensembles with this next system, so one can always hope. Into the extended, none of the operational models have more than a tenth of an inch of liquid equivalent precipitation. You have to look towards the Ensembles for any kind of hope. In the meantime, get out and enjoy the warmth with some jogging, biking, spring skiing. And remember things could be worse…at least we aren’t inverted.

Dry Continues

In short, scraps on the edge of a big trough making landfall in Oregon will bring 0-3 inches of snow to the Wasatch during the day Monday.  After that it will be dry, dry and more dry.

After the brief scrape tomorrow Utah will be underneath an upper-level ridge through the work week. Temperatures will be cool on Tuesday and Wednesday but will return to well above normal by Thursday.  While it might be tempting to write the season off after the hot weather we have had, the Wasatch can really turn it on in February, March and April.  There is yet still hope.  In mid-March 2009 the temperatures in Salt Lake were in the 70’s and everybody was putting skis away in favor of bikes and golf clubs.  And then Alta got 230 inches in 23 days.  So you can never say never.  

In terms of snowpack, Snowbird is still at 90% of average for the date, believe it or not.  Much of northern Utah is also between 60-100% of average.  Of course, many Snotel stations are at high elevations and don’t reflect the brutal conditions down low and on south-facing slopes.