Wasatch Weather Weenies

Here are two things that have never been observed before in Salt Lake City in October. First is yesterday afternoon's sounding, with a 700-mb (10,000 ft) temperature of -18.5˚C, more than 3˚C colder than the previous record of -15.3˚C. Source: SPC If you are wondering, temperatures aloft have already started to increase, so this morning's 700-mb temperature is -15.7˚C.  That's not as cold, but it is the 2nd lowest on record. Second is the overnight minimum temperature of 14˚F, which is the lowest temperature recorded in the month of October in Salt Lake City with records going back to 1874. As of 3:37 AM the temperature at Salt Lake City fell to 14°F. This not only sets a record low temperature for today (10/30), but is also the coldest temperature ever observed in the month of October (records back to 1874). The previous record for both was 16°F (10/30/1971). #utwx — NWS Salt Lake City (@NWSSaltLakeCity) October 30, 2019 Beyond Salt Lake, it was col...

So much to talk about today and so little time.  Hence, I need to do this in rapid-fire mode. Record Cold Crest-Level Temperatures Forecast 700-mb temperatures for Salt Lake City at 0000 UTC 30 October (1800 MDT Today) are -17.7˚C by the NAM and -18.1˚C by the GFS.  These are slightly higher than advertised a few days ago, but will still represent records in the upper-air sounding record for the month of October. Record Cold Surface Temperatures The NWS forecast of 13˚F for tomorrow (Wednesday) morning would be the lowest temperature ever recorded at the Salt Lake City International Airport in October.  I haven't bothered to see what the records are elsewhere, but the current forecast (image grabbed at 7:30 AM MDT Tuesday 29 October) calls for -11˚F in Randolph and, gasp, 24˚F in St. George.  Snow Yeah, it's happening today.  Monitor forecasts.  'Nuff said as I don't have time for a proper forecast. Back-Door Cold Front In weather and war...

October is the new January, at least in Salt Lake City where if you think it is cold this morning, just wait. Really, the past month has been quite cool relative to climatological norms.  The mean temperature at the Salt Lake City International Airport for September 27 through October 27 was 49.8˚F, the lowest mean for that period since 1982 and the 4th lowest on record at the Salt Lake City International Airport (records back to 1928). Source:  http://scacis.rcc-acis.org/ The reason for this cool weather has been a persistent, long-wave, upper-level pattern featuring ridging over the Gulf of Alaska and troughing over the northwest United States.  This has led to northwesterly flow over the western United States, with a series of systems dropping into our area from the northwest or north. Source: NOAA/ESRL Yesterday, steady light snow fell along the east bench in the wake of the first of two major upper-level troughs that will plunge us into a deep freeze th...

It's a beautiful Octobruary day in the Avenues and on the University of Utah campus where light snow is falling and creating a beautiful scene with the fall colors.  My little corner of northwest campus is especially nice where the University has gardened with drought-resistant plants.  So much nicer than grass! This morning, I took a look back at the forecasts produced by the models initialized at 0000 UTC 27 October (1800 MDT Saturday).  The contrast between the GFS and the NAM is significant. Below are 24-hour accumulations (water equivalent) generated through 0000 UTC 27 October (1800 MDT this afternoon).  The GFS (top) has about .1-.25 inches falling over the Salt Lake Valley, with higher amounts in the central Wasatch.  The NAM (bottom) has nothing.    Downscaling and applying a snow-to-liquid ratio to these forecasts and you get accumulations of 0.5 to 2 inches on the benches and greater than 4 inches over the central Wasatch f...

I'm putting in some time at the office today and just took a peek at the models.  Yup, they are terrifying, with an airmass coming in that is NOTHING like anything we have seen in northern Utah since weather balloons began to be launched in the middle of the 20th century.  If you miss the cold of the old days, Mother Nature is going to be giving you a taste. The GFS forecast for 0600 UTC 30 Oct (0000 MDT Wednesday) shows 700-mb (10,000 ft) temperatures near -20˚C across much of northern Utah.  You can even find sub -24˚C air near the Uintas.  These numbers are utterly, totally, and completely ridiculous.  In the sounding archive for northern Utah, there has NEVER been a 700 mb temperature observed below -15.3˚C in October.  It is not hyperbole to say this is an unprecedented early season cold surge during most of our lifetimes.  According to the NWS Salt Lake City Forecast Discussion, the European ensemble forecast mean 700-mb temperat...

This month marks the 100th anniversary of the October 1919 issue of Monthly Weather Review , which included a whole slew of short articles on snow and its impacts.  Lovers of snow and history can check it out at  https://journals.ametsoc.org/toc/mwre/47/10 . Included is a map of the average annual snowfall of the United States, 1895–1914 by C. F. Brooks based on observations from 2,000 stations.  My view is it's a pretty good synthesis, especially over the eastern 2/3 of the U.S.  The "natural advantages" of the Cottonwood Canyons, remain undiscovered. Source: Ward (1919) There's also an article on a "improved form of snow sampler," which is basically a snow coring tube similar to those still in use today. Source: Kadel (1919) At the time, Monthly Weather Review often included abstract reprints from other journals.  The issue includes this synopsis of the snow climate of the European Alps by M. E. Benevent. "The region naturally falls in...

The pattern for the next week is looking like one that will be relatively cool and mainly dry.  Medium-range forecast models indicate that ridging will persist to our west, allowing systems to drop in over Utah from the north or northwest.  These systems will usher in cool air, but are pretty dry, with limited precipitation. The first passes today, although you may barely notice it.  Most of the moisture remains to our east, with the Uintas and maybe the Bear River Range seeing a few flakes.  The Salt Lake Valley will remain dry and if there are flakes in the central Wasatch, they won't add up to anything.  There's no well-defined front, but cooler air will filter in and it will lead to lower high temperatures today and a minimum near freezing at the Salt Lake City airport tomorrow morning. The next system pushes in Saturday.  This is a stronger system thermodynamically , meaning the temperature contrast is larger and sharper.  However, it i...

Since returning from a nearly 6-month stay in Innsbruck in July, hardly a day goes by when I don't wish I could teleport back to enjoy the mountains and culture of the Tirol.  I get occasional e-mails for travel tips, so below is a one-week itinerary, written with just enough detail to give you ideas.  While written as an itinerary, any trip would involve adjustment for weather and snow conditions.  Thus, it is mean to be sampled rather than followed.  I'll begin with some general tips.  Although a car could be convenient for getting to resorts and trailheads, it a liability in town where you are usually better off walking.  If you rent one, you want to be sure you have options for parking wherever you are staying.  Additionally, some ultra cheap rental car deals look great, until you show up to pick up the car and find out you need to pay extra for cross-border travel, insurance, tolls (yes, there are many and you should check out what is and isn't ...

The Alta High Rustler cam is looking quite wintery this morning. Source: Alta Ski Area This is technically, based on my 10 inch minimum requirement, the first deep powder day of the 2019/20 ski season.  As of 0800 MDT, Automated snow sensors at Alta-Collins show an increase of about 13 inches since yesterday afternoon, bringing the total snow depth to 18 inches (note that the snow depth sensor is reading 4 inches too high). Source: MesoWest Sadly, that's below my tolerance levels, so my plan is to sit this one out assuming something really exciting doesn't happen this morning. Much of the water and snow came with the frontal system – the same one that created a deluge at Rice-Eccles Stadium.  If my math is right, Alta got about 0.92" of water and 9 inches of snow through 9 pm.  After that, post-frontal snow showers added some additional low density snow.   Although there was some evidence of lake enhancement at times, a strong lake band never...

The likelihood of skiing this weekend is dependent on several factors, including how much snow the next storm produces, your willingness to sacrifice p-tex, and your tolerance of bodily harm.  I'll focus on the former, beginning with where we are right now.  Prior to last nights storm, snow cover in the Wasatch was scant.  The Alta web cam at the top of Collins shows just a few patches of snow left over from last season. Source: alta.com Last nights storm, however, produced near the top of expectations at upper elevations.  Radar imagery below shows the passage of the frontal system across the area with initially scattered showers followed by a well organized precipitation band.  As a result, Alta is covered by a blanket of white.  Source: alta.com Automated observations from the Alta-Collins site show a total of 0.62 inches of water.  I suspect that the initial snow depth yesterday wasn't actually 4 inches and that this reflects a...