Wasatch Weather Weenies

It's sort of a bizarro-world situation right now with coronavirus running amok, wildfires threatening homes, and late June turning into late April. Saturday night and Sunday, wildfires threatened homes near Lehi, Draper, and Saratoga Springs as two separate fires raged in the urban-wildland interface.  The Traverse Fire near Lehi and Draper was apparently caused by fireworks.  The cause of the Knolls Fire near Saratoga Springs remains undetermined. The cooler weather today is a blessing, but conditions Saturday night and Sunday must have been difficult with strong winds from varying directions. Observations from the flight park near Point of the Mountain show south-southeast winds Saturday morning through about 1300 MDT, then a shift to S-SSW, and finally a shift to north at about 1800 MDT.  Winds from about 1300-1800 MDT were sustained at 35 mph with gusts to nearly 50 and then after the frontal passage peaked with gusts over 60 mph.  Source: MesoWest Th...

In our previous post, we discussed some uncertainties in the forecasts for early next week, with differences in the amplitude and timing of a late-June upper-level trough that was expected to affect Utah's weather.  The model spread has decreased some in the past couple of days with both the GFS and the ECMWF now going for a solution that favors a frontal passage over northern Utah on Sunday (probably noon or later, but follow forecasts as this could change) with the front moving very slowly across the state through Tuesday. On Monday, we will be a state divided meteorologically.  At 0000 UTC 30 June (1800 MDT Monday), the GFS forecast puts the surface cold front over central Utah, with unseasonably cold, northwesterly flow over the northern and western portions of the state and warmer southwesterly flow over southwest Utah.  The ECMWF has a very similar solution, as illustrated by the surface temperature forecast below, with a 30˚F temperature contrast between s...

A weak trough will move over northern Utah tomorrow, lowering maximum temperatures in the Salt Lake Valley into the mid 80s and bringing a chance of scattered showers and thunderstorms.  I mentioned how great it is that we keep seeing these troughs in my previous post, and there's a chance of another, stronger one, early next week, but the impacts on northern Utah vary substantially depending on the forecast model.  The GFS forecast valid 1200 UTC (0600 MDT) Monday shows a deep trough over the northwest U.S. with a cold front moving through northern Utah.  The GFS then brings the trough directly through the northern half of the state and by 1200 UTC (0600 MDT) Tuesday, forecast 700-mb temperatures are just below 0˚C, cold enough for snow in the upper elevations above probably 9000 feet, although possibly lower.  However, the ECMWF has a much different evolution for northern Utah.  It stalls the trough over the Pacific states.  We would...

The average temperature at the Salt Lake City International Airport for the first three weeks of June was 68.9˚F.  This is quite comparable to the first three weeks of last June (68.6˚F) and considerably cooler than the first three weeks of June 2015, 2016, 2017, and 2018, when mean temperatures were at or above 74˚F.  Source: NOAA Regional Climate Centers So, compared to recent standards, this has been a pretty nice June.  However, it's still about 2.4˚F warmer than the 20th century average for Salt Lake City. It's also been a June of extremes.  Just check out the roller coaster we've been on below.  We hit 100 on June 5, the earliest 100 ever recorded at the airport, then plunged downward with highs of 60 and 55 just 2 and 3 days later, respectively.  We subsequently seen big swings continue through today.    Source: National Weather Service Today looks splendid with a high of 84 forecast for the Salt Lake City Airport by the Na...

Yesterday's summer solstice is behind us and the days are now getting (slowly) shorter.  There is still much summer and fall to enjoy, but the orbital parameters strongly suggest that ski season will come. What the ski season will look like is a big question.  Perhaps we'll be close to a vaccine or there will be a treatment breakthrough that allows us to move forward as we have in the past.  We all hope that's the case, but there's also the possibility that our best strategies remain non-pharmaceutical interventions such as distancing, masking, etc., as they are today. Some hints at what things might look like are being provided by resort plans in Australia, where resorts are beginning to open.  Traveller reports  that resorts are beginning to open this coming week with what Falls Creek resorts calls "business as unusual."  It sounds like lift tickets are being sold in advance, chairlifts will be loaded with half capacity (unless riders are from the sam...

Probably 90% of the people who go out to the Stansbury Mountains are targeting Deseret Peak.  That's a worthy objective, but there are other options.   Today, I hiked up to South Willow Lake, which similar to the Deseret Peak Hike starts in the Loop Campground at the end of the road in South Willow Canyon.  However, instead of taking the standard Deseret Peak Hike, one instead takes the Stansbury Crest Trail, which meanders along at an elevation of about 9000 feet. The views are quite nice back to the east with green desert-range meadows contrasting with the now baked out Tooele Valley.  The Wasatch Range can be seen in the distance.   It is the meandering through basins and upper-elevation meadows that makes the hike for me.  The lake itself is a worthy target, but isn't all that spectacular. On the return, one looks directly at the famed Twin Couloirs, which are still holding a little snow.   I skie...

An incredible tweet below from @terrybnd with a time lapse of a mountain wave and downstream hydraulic jump.  I don't know precisely where it was taken, but they commented that they were enjoying "lovely scenes of radiation fog enveloping the fells on and around Ullswater" which is in the Lake District of England. Aye. Here’s a peek at rough unfinished timelapse I captured of it. pic.twitter.com/yuLubcQR6r — Terry Abraham (@terrybnd) June 19, 2020 The video shows a classic high-amplitude mountain wave with plunging flow producing a "waterfall cloud" on the lee side of the ridge with a hydraulic jump and rotor developing immediately downstream.  The cloud structure on this occasion is ideal for tracing the flow.  A schematic of the flow in these situations is depicted below, although you have to mentally flip it and reduce the scale a bit to match that in the time lapse.  Source: Whiteman (2000) The flow during downslope wind events along the northern ...

Widespread precipitation with embedded heavy rain and thunderstorm fell across northern Utah last night.  Below is the radar image from 0548 UTC (1148 PM MDT) illustrating the widespread nature of the precipitation and, at this time, thunderstorms moving across the eastern Salt Lake Valley.  Source: NCAR/RAL The average 24-hour rainfall reported to MesoWest for the period ending around 8:30 AM MDT by stations along the northern Wasatch Front was 0.63" with a maximum of 1.61".  For the Salt Lake and Tooele Valleys it was 0.44" with a maximum of 0.82." I suspect many people were surprised by this event and indeed it was a low probability possibility just two and a half days prior.  For example, below is a plume of downscaled Short-Range Ensemble Forecast system (SREF) forecasts for the Salt Lake City International Airport.  There are 26 forecast members that make up the SREF and 23 of those members produced less than 0.1" of precipitation and most prod...

The University of Utah is slowly but surely rolling out more information about returning to campus for Fall 2020 at  https://returntocampus.utah.edu/ .  Unfortunately, these web pages aren't data and there isn't a clear traceable way to see updates, but it appears some additional information has been added recently.  There are two changes that I see as an improvement.  First, language related to face coverings has been strengthened.  It now clearly says that students must wear face coverings in class.  Second, the the faculty and staff information page at  https://returntocampus.utah.edu/faculty-staff-information/  states that on-campus office work is allowed but should be minimized, with remote work encouraged.  Nevertheless, I think these plans, which state that "classes will resume — in a mixture of in-person and hybrid delivery — on campus on August 24" are overly optimistic and fail to face reality.  I favor an approach in which...

Highs in the 80s are quite tolerable in Utah, but 90s not so much.  Yesterday's high of 91 and today's forecast high of 95 are outside my tolerance limits.   The good news is that we have some cooler air moving in tomorrow.  The NAM 850-mb (about 5000 feet above sea level) temperature and wind forecast valid at 1500 UTC (0900 MDT) tomorrow morning shows a cold front moving across northern Utah that should knock temperatures down for the weekend.   National Weather Service Forecast for the Salt Lake City airport calls for a high of 85 tomorrow and a very pleasant 76 on Sunday.   Enjoy, but keep your distance.  

A number of grassroots campaigns are holding a strike today for black lives (e.g., #ShutDownStem and #ShutDownAcademia) to focus on discussions with colleagues about anti-Black bias in the world and in academia.  My colleagues in the atmospheric and related sciences have a call to action for an antiracist science community at  https://notimeforsilence.org/  that I encourage you to read today.  I regret that pursuing antiracist policies and culture has not been a greater priority for me during my career.  I am taking time today to reflect, listen, and understand.  In the future, I am committing myself to stronger advocacy for the promotion of antiracist policies and inclusive culture in my department and college, as well as across the atmospheric and related sciences. 

The Utah Department of Transportation has identified three alternatives for more in-depth study to improve transportation in Little Cottonwood Canyon.  Information is available at  https://littlecottonwoodeis.udot.utah.gov/  and you can also input comments from June 8 – July 10, 2020 via the web site or other avenues described at the site. The three alternatives are summarized below, including capital and O&M costs. Source:  https://littlecottonwoodeis.udot.utah.gov/wp-content/uploads/2020/05/9234_42_LCC_EIS_Alternatives_Project_Factsheet_FIN_WEB.pdf I thought I would talk a little about the gondola option based on my experience in Austria last year.  We have also discussed this in a previous post in December 2019 . Stubai Glacier ski resort in the upper Stubai Valley south of Innsbruck has a tri-cable gondola similar to the one proposed in the third alternative above.  The gondola, labeled 3S Eisgrat I and II below and referred to as the Eisgr...

As a professor and the parent two college students, I'm deeply concerned about university plans to "reopen" in the fall. Reopening plans for the University of Utah, where I am a professor and my son attends, are available at  https://returntocampus.utah.edu/ .  This web page is not very specific, but states that classes will resume "in a mixture of in-person and hybrid delivery," that fall break will be cancelled, and that instruction will shift to all online after the Thanksgiving break.  Physical distancing "protocols" will be in place.  All individuals "are expected" to follow state and local guidelines for wearing face coverings. Not discussed at all but hopefully forthcoming soon, are testing protocols, how the university will define and deal with outbreaks, whether or not mask wearing will be mandatory, options for high-risk students, etc. My daughter attends Arizona State and their reopen information is a bit more detailed and av...

Active weather with lightning, thunder, strong winds, and hail continues today.  Below are a couple of radar images from this morning showing strong storms in the Wasatch Front area. We had a round of strong winds here in the upper Aves this morning and also some small hail that was a bit larger than pea sized. So far, the big winner in the hail category appears to be Plain City.  A viewer tweeted this photo to Chase Thomason of KUTV2 news.  More hail photos coming in. pic.twitter.com/cimueZYAMt — Chase Thomason (@ChaseThomason) June 7, 2020 Keep an eye on the sky as the thunderstorm threat continues today.

Mother Nature will be throwing an active day at us today and she is already bringing the goods. I was up early this morning as I have quite a bit of yardwork to do today, but the weather is not cooperating.  Showers and thunderstorms extend from the Oquirrhs into eastern Utah at 1300 UTC (0700 MDT).  These storms have been moving northward, leaving a trial of lightning strikes from I-70 to just north of Evanston.  The highest lightning-strike densities are well east of I-15, but there have also been a few in the Salt Lake Valley and adjoining Wasatch Mountains.  Source: LightningMaps.org.  Lightning in hour ending at 0709 MDT. Today will be the epitome of if you don't like the weather, wait 5 minutes.  The latest HRRR shows periods of showers and thunderstorms in the southerly flow ahead of the front (which we are currently in) and with the approach and passage of the front around 1800 MDT.  I've selected a few forecast hours below to il...

Being a severe-weather aficionado in Utah is a bit like being a powder skier in Oklahoma.  The pickings are slim.  However, unlike powder skiing in Oklahoma, which is essentially non-existent, there are a few days a year where something exciting might happen around here.  The Storm Prediction Center puts parts of Utah in the marginal severe thunderstorm risk category over the next two forecast periods.  A severe thunderstorm is one with wind gusts of 58 mph, hail at least an inch in diameter, and/or a tornado.  Marginal risk means that the storms could be spotty and limited in duration and/or intensity.  However, this is Utah and marginal is about the highest you see. The SPC convective outlook discussion highlights that increasing moisture, strengthening wind shear, and other environmental characteristics should be favorable for isolated strong storms, potentially with strong winds and hail.  The NWS Forecast office in Salt Lake City ha...

Major changes are on tap weatherwise over the next several days. Today looks to be hot and tomorrow (Friday) even hotter as a closed low off the coast of Baja California begins to fill and lift into the southwest United States.  This leads to strong southerly flow across the Great Basin with temperature climbing and fire weather conditions deteriorating.  NWS forecast highs for the Salt Lake City Airport are 91˚F today and 96˚F tomorrow.  Disgusting. Saturday's forecast is crapshootish as the former closed low continues to fill and moves across Utah and a much deeper trough approaches from the west.  Right now, the GFS has the former moving across Utah in the morning and producing showers and thunderstorms producing the heaviest precipitation over central and eastern Utah. The situation for northern Utah is pretty complicated due to the weak atmospheric stability, a front approaching from the west, and a moisture dryslot.  My guess is that there wi...