Wasatch Weather Weenies

When it comes to the impact of global warming on snow, there will be few (if any) winners but some will suffer more than others.  Lower elevations are generally more vulnerable than higher elevation areas since temperature decreases with height.  For a given increment of warming, lower elevation regions see an event greater fraction of precipitation fall as rain, more and more substantial snow loss events, and greater loss of shoulder-season snowfall and snow compared to upper-elevation regions. The vast majority of Nordic (i.e., cross country) ski centers and public trails are located in valleys and at relatively low elevation.  Thus, Nordic skiing is and will be suffering more than Alpine skiing, especially in ski regions where there is great vertical relief, such as Utah and the European Alps.  For the most part, this has been a dismal Nordic ski season in Europe, including the Alps and Scandanavia.  Most of the Nordic races I've watched have featured sno...

Excitement is running high in my department as we prepare to host the Research Experiences In ALpine Meteorology (REALM) program this summer. REALM is a National Science Foundation sponsored Research Experiences for Undergraduates (REU) program designed to enable the active participation of undergraduates in research.  What is unique about REALM is its focus on mountain weather.  We have received applications from students with diverse backgrounds from all over the United States.  Those accepted into the program will have an opportunity to learn and recreate in the mountains of Utah, which I expect will be transformative for many.  I personally remember my first trip to Utah when I was 16 years old and how our trip up Little Cottonwood Canyon further kindled my interest in mountain weather and winter storms. Support from the National Science Foundation and University of Utah provides ten students with lodging, travel funds, and a stipend.  From late May ...

Strong winds accompanied a cold front that moved through northern Utah last night.  In my neighborhood, it's garbage pickup day and there were many tipped cans and much garbage strewn about, not to mention bleary-eyed people who were awoken in the night by windows rattling.  The strong winds came in the northwesterly flow following the frontal passage.  Peak gusts at the Salt Lake City International Airport (41 mph) occurred at about 0820 UTC (0120 MST).  The situation shortly after that at 0900 UTC (0200 MST) when I was awoken by the storm is shown below and illustrates the widespread northwesterly postfrontal flow.  A quick look at the overnight observations shows many valley sites recorded peak gusts of over 50 mph.  The peak gust in the Salt Lake Valley appears to be 59 mph on the Baccus Highway (SR 11) near 6200 South (a somewhat elevated location on the west bench.  The University of Utah reached 50 mph on the top of the 8 story William Br...

A few tidbits today for your Sunday reading. Lone Peak Wilderness Is there a more spectacular near-urban wilderness in the contiguous United States as spectacular as the Lone Peak Wilderness?  It's a rugged place, with much of it more accessible in winter and spring than summer and fall.  Yesterday near White Baldy Hard to believe there was talk at one time of putting a tram up the iconic Pfeifferhorn.  Thankfully that never happened.   Wasatch Oddities One of the curious aspects of the central Wasatch Mountains is that the highest terrain isn't on the mountain "crest" or hydrologic divide like it is in the northern Wasatch, but west of it.  A good example of this is provided below, looking north from upper Red Pine Canyon at the high ridgeline above Little Cottonwood.  Note how the terrain is highest from Twin Peaks on the left (west) to Monte Cristo Peak center right, and then descends as one moves further east to the Emmas and env...

NOAA has announced an upgrade to its computing resources for weather and climate prediction.  The full press release is available at  https://www.noaa.gov/media-release/us-to-triple-operational-weather-and-climate-supercomputing-capacity .  The upgrade consists of two Cray computers, each with a capacity of 12 petaflops (typically two identical systems are used in weather computing to ensure redundancy and operational reliability).  A petaflop is one quadrillion floating-point operations per second.  The NOAA press release suggests that this will keep the agency on par with leading weather forecast centers around the world.  It will help, and it will lead to improved forecasting for the United States, but I'm not sure it will enable us to get on par with ECMWF, at least in terms of global weather prediction.  In January, the ECMWF signed a contract in January that is estimated to provide two computers, each estimated to have a capacity of 20 peta...

Sunrise view this morning in the Avenues You'll be hard pressed to find a more spectacular airmass than the one resident over northern Utah this morning.  Not a cloud in the sky and unlimited visibility.  Simply spectacular! Under clear skies this time of year, one might expect a large difference between the maximum and minimum temperatures, but that hasn't been the case at the Salt Lake City Airport.  Yesterday's maximum was 36˚F and the overnight minimum was only about 21˚F (it might go slightly lower than that).  That's a 15˚F range, which is smaller than average (19˚F) for this time of year. Source: MesoWest Tour our southeast, the Rush Valley south of Tooele can often get quite cold, and last night it got down to about 6˚F.  That's impressive compared to Salt Lake City, but still only 28˚F cooler than yesterday's max.  Here too, the daily range of temperature is a bit subdued despite the clear skies. In contrast, if we go east of the W...

Snowpack water equivalent observations from Snowbird show that, for the first time since mid October, we are now running behind the 2018/19 season.  Source: NWS/CBRFC The numbers are so close, however, that it's probably better to say that we're in a dead heat given the errors and uncertainty that exist in such measurements. Elsewhere in the central Wasatch, Mill D North is also in a dead heat, but Brighton and Thaynes Canyon are lagging behind. Source: NWS/CBRFC Source: NWS/CBRFC Source: NWS/CBRFC Further, if one assumes these observations are representative (and that is not necessarily a good assumption, but what the hell), these observations suggest that western portion of the central Wasatch has been favored this winter more so than usual.  This has led to above median snowpack in the western portion and near median in the eastern portion.  I note, however, that this is probably not a statistically or physically representative sample given that t...

Today is apparently Wasatch Backcountry Appreciation Day.  I saw that in a tweet yesterday, so anything is possible.  Everyday should be Wasatch Backcountry Appreciation Day.  In celebration, I leave you with some photos, in no particular order, and remind you that life is short and powder precious. 

Still on eastern time, I was up early this morning, well before the crack of dawn.  A quick walk outside revealed relatively mild temperatures, a subjective observation confirmed by the morning sounding from the Salt Lake City Airport, which showed a surface temperature of 38˚F and a freezing level near 8000 feet. Based on temperature alone, one would expect rain on the valley floor and benches from a sounding like that, but a couple of hours later, it was snowing and accumulating on grassy surfaces. Did a front go through, lowering the temperature, freezing level, and snow level?  No.  The lowering of temperature, freezing level, and snow level occurred due to sublimation, evaporation, and melting of precipitation.  These processes are called diabatic effects by meteorologists.  To anticipate such effects, it is best not to use temperature, but instead wet-bulb temperature .  Wet-bulb temperature is the temperature that air will cool too if yo...

I finally returned to Salt Lake City last night after a week in Greenbelt, Maryland at the National Weather Service Weather Prediction Center.  It was a good week professionally, but it was mostly cloudy and rainy and my exercise was limited to the stationary bike at the hotel and a walk through the University of Maryland campus.  The only evidence of mountain weather that I saw there was a post-frontal lenticular generated by the upstream Appalachians on Friday morning.  Thus, I was chomping at the bit to get out this morning and headed up to Round Valley for an early morning skate.  Conditions were excellent.  The snow was firm and fast with a nice groomer buff on top.  I didn't even work hard and still came in with my fastest pace of the season.  Having not been in the mountains yet, I can only assume that we are in need of a reset for touring and alpine skiing.  It looks pretty good that this will happen.  The NAM forecast loop belo...

I'm at the Salt Lake airport to do my duties as a principal investigator and suffer through a week on the east coast away from snow.  The view this morning of the northern Wasatch was beautiful, with a spectacular lenticular cloud sitting right on the Wasatch crest.   Such a cloud pattern is consistent with easterly downslope flow, as are the low level cumulus clouds closer to the airport.  Those clouds are likely forming in the updraft where the downslope flow experiences a hydraulic jump, similar to what occurs in some situations during water flow over a rock.  The easterlies are quite evident in the weather observations near the mountains and to the east. Source: MesoWest Curiously, if you look carefully, you can find observations with westerly flow just to the west of bountiful and at the Salt Lake City Airport.  That is evidence of a rotor, a circulation that typically forms just downstream of the hydraulic jump.  Below is a concept...