Stansbury Scenes

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 skied the west one once with some friends in a previous life. 

According to the kid pictured below, they were skiable today, although the exit involved a much longer slog than we had.  Probably a bit more than 2000 vertical feet of snow free ascent and descent 

There were quite a few people out today and cars were parked in every nook and cranny near the trailhead when I left this afternoon.   

Mountain Wave Eye Candy

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 Wasatch, which tend to be strongest near Centerville and Farmington, is similar.  However, because the Wasatch are much taller than the hills of the Lake District, one typically does not see cloud plunging down the entire lee (west) slope.  Instead, one sees just a cap cloud on the ridge, as in the photo below from a modest downslope wind event in February (and my last trip through the Salt Lake airport just prior to COVID). 

In the downslope flow, the air sinks and warms, leading to a decrease in relative humidity and cloud evaporation.  However, evaporation takes time.  In the time-lapse above, the amount of warming, resulting decrease in relative humidity, and time needed to evaporate cloud droplets are not large or long enough to create a large cloud-free region (although there is some clearing).  Thus, the clouds provide a pretty good tracer for the low-level flow.

What you can't see is the wave-breaking region aloft, as depicted in the schematic.  While rotors and other features associated with downslope flow are hazards for aviation, the wave breaking region, which is often cloud free, is another as it is often accompanied by turbulence, which can be severe. 

About Last Night

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 produced a few hundredths or less. 

Another perspective on that forecast is provided below.  The ensemble mean precipitation is less than 0.1" across much of northern Utah except in the Uintas and the far north.  However, the ensemble maximum precipitation exceeds 0.5 inches in several areas. 

Another perspective is provided by the sequence of GFS forecasts below, which are 66, 54, 42, 30, and 18 hour forecasts of 6-hour accumulated precipitation (color fill) and instantaneous wind valid 0600 UTC (0000 MDT) 17 June (i.e. midnight local time last night).  Note how these forecasts initially kept scattered precipitation to our north, but trended to more widespread and heavier precipitation further south over time (but still not as much as observed). 

Finally, let's take a look at the evolution of NWS forecasts during this period.  To do this, I'll use their zone forecast products issued for the Salt Lake Valley at the times indicated below.  I'l begin with the forecast issued Sunday as it had no hint of precipitation.

• 230 PM MDT Sun June 14: TUESDAY NIGHT...Mostly cloudy. Cooler. Lows around 50.
• 259 AM MDT Mon June 15: TUESDAY NIGHT...A slight chance of showers and thunderstorms in the evening, then a chance of rain showers after midnight. Mostly cloudy. Cooler. Lows around 50. North winds 10 to 20 mph around midnight. Chance of precipitation 30 percent.
• 245 PM MDT Mon June 15: TUESDAY NIGHT...Mostly cloudy with a 50 percent chance of rain showers. Cooler. Lows around 50. Northwest winds 10 to 20 mph.
• 251 AM MDT Tue June 16: TONIGHT...Partly cloudy with a chance of rain showers and a slight chance of thunderstorms in the evening, then cloudy with rain showers likely and isolated thunderstorms after midnight. Cooler. Lows around 50. North winds 10 to 20 mph. Chance of precipitation 60 percent.
• 1022 AM MDT Tue June 16: TONIGHT...Scattered showers and thunderstorms in the evening, then numerous rain showers after midnight. Mostly cloudy. Lows in the lower 50s. North winds 10 to 20 mph. Chance of precipitation 60 percent.
• 202 PM MDT Tue June 16: TONIGHT...Mostly clear with scattered rain showers and isolated thunderstorms in the evening, then mostly cloudy with numerous rain showers after midnight. Lows in the lower 50s. North winds 10 to 20 mph. Chance of precipitation 70 percent.

So you can see how on Sunday, no precipitation was in the forecast, and then how the forecast evolved with time with increasing chances of measurable precipitation.  

The forecast issued at 230 PM Sun June 14 for the northern Wasatch Front was mostly cloudy with a 20 percent chance of rain showers and for the Cache Valley was mostly cloudy with a 40% chance of rain showers. 

So, this was a case in which "the model trend was not our friend."  The rain late yesterday and overnight was significant, exceeding the maximum precipitation at some sites for the calendar day (e.g., Logan, Ogden).  I think it is safe to say that forecasts issued on Sunday did not prepare the public for such a significant event.  This reflects a number of factors, including the evolving nature of the storm system, shortcomings in our current forecast systems, and limitations in how we currently communicate forecast uncertainty.  

It is a reminder to all of us who work in the weather enterprise that we have a lot of work to do.  

Are Campus Reopening Plans Realistic?

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 as many classes as possible are taught online and we do all possible to reduce risk for on-campus instruction of classes that cannot be effectively taught online including but not limited to lab and performance classes. 

The simple fact of the matter is that the United States and the State of Utah have failed to contain the coronavirus.  We've had months to reduce transmission, improve testing and tracing, educate the public on the importance of mask wearing and distancing, and reduce infections, and yet here we are with cases on the rise throughout the state.  The genie is out of the bottle and it is hard to put it back in.

The University of Utah has more than 24,000 undergraduate and 8,000 graduate students, plus faculty and staff.  Most commute daily to campus from all over the Salt Lake Valley, Wasatch Front, and surrounding region.  Parking is limited on campus.  Public transportation is essential, with distancing likely impossible at rush hour times. 

We can enforce distance and masking protocols all we want on campus, but the reality is that students are going to partake in risky behavior and bringing them together every day is a recipe for transmission.  It may be hard to believe, but I was a university student once and I can assure you I wasn't studying in the library 7 days a week.  As psychology professor Laurence Steinberg of Temple University wrote today in the New York Times, "Expecting Students to Play it Safe if Colleges Reopen Is a Fantasy."  He goes on to say that the safety plans being proposed are delusional and could lead to outbreaks of COVID-19.  I would have said will. 

There appears to be no organized method of providing comments to the University about the reopening plans.  I have been told to communicate via my department chair and college dean and encourage you to voice your opinions through those avenues as well.  It is clear that input from the faculty has resulted in some changes in plans over the past week or two.  I'm not sure how much student input has been solicited through this process, but it is important.  The "Project Marmalade" team that is putting together these plans is comprised almost entirely of administrators and has no student members.  They need to hear from everyone. 

Cooler Weekend Ahead

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.  

#ShutDownStem

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.