Wasatch Weather Weenies

The storm cycle that has blessed us is coming to and end and, when combined with the Thanksgiving weekend storm cycle, leaves us in pretty good snowpack shape for early December. As of midnight last night, every Wasatch Snotel except for Parish Creek (98%) and Mill D North (94%) was above median snowpack water equivalent for the date.   Source: NRCS Those are also the only Snotels in the central and northern Wasatch with less than 5 inches of snowpack water equivalent.  If you are looking for the fattest snowpack, you'll find it in the upper Cottonwoods where Snowbird and Brighton are at 6.6 and 6.5 inches, respectively, and Ben Lomond Peak and Trail, which are at 8.2 and 5.3 inches, respectively.  The 5.3 inches at Ben Lomond Trail represents 241% of median and is especially impressive given that it sits just below 6000 feet.  Although there may be some lingering snow showers today, the storm cycle is pretty much winding down.  This week rep...

I got out for my first ski tour of the season yesterday and was pleased to see more snow than we saw probably at any point until late January of last year.  Conditions were good, with the snowpack dictating cautious meadow skipping. USA bowl was apparently the "it" place for most as it looked nearly as tracked as Solitude did across the street. The resorts were packed as traffic in the canyon was clogged in the morning and cars were parked up and down the road as far as the eye could see.  Sadly, we enter another season with little progress made to alleviate congestion and no real plan in sight.   Shifting to more positive news, the snow continues this morning with about 4" of pixie-dust overnight on the Alta-Collins stake through 8 am.  The situation right now is quite interesting as we are basically just to the northeast of an area of strong northwesterly flow where there are a number of small-scale eddies, known as mesovorticies ,.  I have...

The last week has been a godsend for Wasatch snow.  Precipitation totals (water equivalent) since Thanksgiving (11/22) are now at about 3.5 inches at Alta Collins and 4.5 inches at Snowbasin Middle Bowl.  Source: MesoWest With 8 inches overnight, the total snow-depth sensor at Alta Collins cracked 40 inches, which officially marks the beginning of "early season skiing" based on the Steenburgh snow-depth scale.  Source: MesoWest If you are wondering, I consider anything before we get to 40 inches to be "pre season."  Some might grumble about that number being too high, but remember that this blog is about mountain meteorology and snow snobbery.   Here's something we haven't seen around here in a while, SNOTEL stations with above median snowpack water equivalent.  Paraphrasing Gordon Gecko, "green is good" (blue is even better) and there's quite a bit of it on the map below.  Relative to median, here are a few specific numbers: Sno...

Looking south from the upper Aves at around 7 AM this morning Yesterday's precipitation fell with little wind, allowing for to develop overnight along the Salt Lake Valley floor.  This has led to a difficult commute in some areas and some spectacular views from bench areas above the fog, such as the upper Avenues pictured above.  I am hoping that the Bay Area feel of the view might be a good omen for the Utes as they prepare to face the Huskies in Santa Clara on Friday for the Pac-12 Championship. The fog was also evident from the top of the tram at Snowbird.  Time lapse video from campus, compiled by Brian Blaylock, was really fascinating to watch and illustrates the complexity of local flows and wind shear that exists within the Salt Lake Valley and how rapidly they can change, even in a relative quiescent flow pattern.  Wait for it at 10 seconds.

Although it is not unusual for the GFS to be wetter than the NAM, the difference between the two models over the next couple of days is exceptionally large.  For Alta from 5 AM this morning through 11 AM Saturday, the 0600 UTC initialized NAM generates 0.84 inches of water and 12 inches of snow.  In contrast, the 0600 UTC initialized GFS generates 2.84" of water and 39 inches of snow.  There are several reasons why this is the case, but a major one is the track and characteristics of the storm that will move across the region Thursday night and Friday.  The NAM produces a trough that is displaced further south with precipitation occurring mainly near and south of the Salt Lake-Utah County line. In contrast, the GFS trough is further north and precipitation occurs all the way up into southern Idaho.  There are also some details about the upper-level trough orientation that are different, but which I won't get into here.  Although I do not have co...

The post is a bit redundant with the previous, but it's been so long since I've seen a model forecast like the GFS 10-day loop below that I feel the need to share it.  Check out the action across the southwest.  The European model is generally similar for the first 6 days or so, but deviates quite a bit on the last few days of the loop.  In addition, the GEFS shows a wide of solutions at 10 days. Source: Penn State E-Wall Thus, perhaps the GFS run might overdo the persistence of the southerly storm track, but we can still enjoy seeing it as it sprinkles some variety into our lives. The downscaled 7-day NAEFS quantitative precipitation (water equivalent) and snowfall probabilities also show nearly the all the mountains of the western U.S. getting some action over the next week.  For northern Utah, much will depend on how productive the bits and pieces are and how far south the storms track.  For once, we probably need to be hoping the storms shif...

The next 7-10 days we will see something that we've seen little of over the last few years (with one notable seasonal exception) and that is a series of storms affecting the southwest U.S. The loop below covers the period from 1200 UTC 24 November through 1200 UTC 1 December with jet-level wind speeds in excess of 40 meters per second (80 knots) color filled.  Note how the jet stream over the eastern Pacific and most of the US is south of 40ºN for much of the period, especially after 1200 UTC 27 November (5 AM MDT Tuesday). With the storm track to the south, the southwest will be seeing a series of storms and getting some much needed precipitation.  Over the next 10 days, the GFS is putting out over 4 inches of water equivalent the Sierra Nevada (peaks over 6 inches) and more than 2 inches in higher altitude areas of Utah and western Colorado. This is not a pattern with a huge tap of persistent, tropical moisture.  Thus, water totals are not ginormous, but tha...