Wednesday, July 31, 2019

Will This Monsoon Surge Produce?

An impressive surge of monsoon moisture is currently occurring over Utah.  Below is a loop of High Resolution Rapid Refresh (HRRR) model analyses and forecasts of precipitable water for the period from 0400 UTC 31 July (2200 MDT yesterday) through 0200 UTC 1 August (2000 MDT this evening).   Precipitable water is the depth of water you would have on the ground if you were to condense out all the water vapor in an atmospheric column.  Thus, it is a measure of the total integrated water vapor in the atmosphere.  Note how high values move northward from Arizona and the lower Colorado River Basin into Utah.  Values in Salt Lake City increase from about 12 mm (0.5 inches) to about 30 mm (1.2 inches). 

Surface dewpoints overnight increased steadily with the surge, as illustrated by meteograms for St. George and Salt Lake City. 

The latest (1505 UTC/0900 MDT) satellite and radar analysis shows extensive upper-level cloud cover over Utah.  Relatively weak and spotty radar returns are evident over northern Utah, although much of that is probably not reaching the ground yet. 

Concerns for the forecast today include where will the moisture go and how will the forcing for convection and thunderstorms evolve.  The HRRR simulated reflectivity forecast does bring some showers into northern Utah, some of which may be strong enough to generate lightning and thunder.

No model today can reliably predict the timing, location, and intensity of monsoon precipitation and thunderstorms.  Be aware of the possibility of rain, which could be locally heavy, as well as the possibility of lightning and thunder.  Below is the latest summary from the National Weather Service.

Also, remember that individual storms can sometimes produce more precipitation than indicated by precipitable water values.  This is because storms process water vapor not only from the column overhead, but also from the surrounding area.  Thus, precipitable water should not be interpreted as the maximum amount of precipitation that could fall, but instead simply as a measure of how much water vapor is in the atmosphere. 

Monday, July 29, 2019

Meteorology of a Monsoon Surge

Last week, we discussed how we were in a pattern characterized by persistent upper-level ridging over the western United States, but that "critters in the woods" would modulate the monsoon moisture and shower and thunderstorm activity (see Persistent Large-Scale Pattern with Critters in the Woods). 

One of those critters gave us the relatively pleasant weather on Saturday and another will be affecting northern Utah on Wednesday. 

The setup for Wednesday illustrates how both large-scale and small-scale features play an important role during the monsoon.  The situation at 0600 UTC 30 July (0000 MDT Monday) shows a high-amplitude upper-level (500-mb) ridge centered near the 4-corners area.  Anticyclonic (clockwise) flow around this larg-e scale feature results in westerly flow to our north and easterly flow over northern Mexico as depicted below. 

However, there is also an important smaller-scale circulation feature over northern Mexico.  I have identified this feature using contours of vorticity, a quantity used by meteorologists that essentially represents the circulation density.  Vorticity helps identify areas of strong shear and curvature in the flow.  Note that there is a local maximum, denoted by an X, over northern Mexico.  Meteorologists call such a feature a vorticity maximum, and this is our critter in the woods for Wednesday.

Typically, the large-scale flow "steers" vorticity maxima, but vorticity maxima also interact with the large-scale flow and can strongly affect the weather.  In the GFS forecast panels below, which cover the period through 0600 UTC 1 Aug (0000 MDT Thursday), the vorticity maximum is coaxed northward by the circulation associated with the large-scale ridge while at the same time it intensifies, resulting in enhanced southerly flow to its east. 

Together, this pattern leads to a very pronounced northward surge of monsoon moisture into Utah, as depicted below by the loop of precipitable water.

For the forecast, however, there are some differences in where the models place the moisture.  For instance, the GFS forecast for 0000 UTC 1 Aug (1800 MDT Wednesday) has the moisture plume covering central and western Utah, whereas the NAM has the moisture plume in central and eastern Utah. 

We'll see how this all plays out, but keeping an eye on forecasts and recognizing the potential for thunderstorms and related hazards is essential for Wednesday and Wednesday night. 

Sunday, July 28, 2019

Central Wasatch Peak Bagging

I've been in Salt Lake City for nearly 25 years and in that time I've never been to the top of the American Fork Twin Peaks.  That changed today as my son and I bagged it via Gad Valley from the base of Snowbird. 

It's a really great hike, with some ridge scrambling that is fun and offers some great views. 

The photos above were taken in fairly meadowy areas.  In others, there's some rock hoping and scrambling to be had, but not difficult.  Perhaps class 3 in a few places.  In places there's a faint trail, but not much.  

Views from the Red Stack were really spectacular. 

Ditto for the views from the American Fork Twin. Timpanogos still has plenty of snow up high and the USFS was recommending ice axes/traction devices for ascending the Timp "Glacier".  

I didn't feel bad about leaving my skis at home, however, when looking down Pipeline.

I don't know where the Snowbird expansion plans are these days, but I hope that the summit of this  magnificent peak remains unspoiled.  

Friday, July 26, 2019

Weather Hazards and Bike Racing

I'm a big fan of the Tour de France, despite cycling's spotty history with performance enhancing drugs.

In recent years, Team Sky (now Team Ineos) has dominated the race, making for generally boring racing, but this year, the race has been wide open, with as many as six riders having a legitimate shot at the yellow jersey entering the final three stages.  Further, the leader entering stage 19 (of 21), Julian Alaphilipe, was not a pre-tour favorite, adding to the intrigue.  Major surprises in long stage races are few and far between.

I was hopeful that today's stage would remain dry after consulting MeteoFrance's Arome model yesterday, but it wasn't to be.  Thunderstorms laid down a major coating of hail on the end of today's stage, necessitating a halt of action while the riders were descending from the penultimate climb.  Conditions along the route to come were indeed unsafe.  Comically, overhead shots showed what looked to be a snowplow in action.

Sadly, some news reports claimed that the tour was stopped because of a snowstorm.

Hail ≠ snow.  Oh the pain and agony of it all!

There were also reports of a debris flow.
There was a time when the race would have gone on through such insanity, but they made the right decision today.

Tour of Utah organizers should take the opportunity to learn from this as "America's Toughest Stage Race" could similarly be affected by hazardous weather including but not limited to hail, flash flooding, debris flows, and lightning.

Thursday, July 25, 2019

Update on Eastern Alpine Glaciers

It was a pretty good snow year in the eastern Alps, but due to global warming, it's damn hard to have a year in which there isn't a net loss of glacier mass.

When we left Innsbruck at the end of June, the seasonal snow still covered much of the high eastern Alps, but that's changed in the past three weeks.  Seasonal snow on the Hintereisferner, Austria's best studied glacier, is disappearing rapidly, leaving grey glacier ice. 

Hintertuxer Glacier is Austria's only year-round ski area.  Here too, the deep seasonal snow cover is disappearing rapidly. 

Finally, there is the Schneeferner on Zugspitze, which is to the right of the building pictured below. It's beginning to suffer too.

I suspect at the end of summer, we'll see a net loss of mass for most of the glaciers in the eastern Alps.  Even in a good snow year, the summertime temperatures that exist today do their damage.  Additionally, the prolonged exposure of grey glacier ice results in increased absorption of solar radiation, further accelerating the loss. 

Tuesday, July 23, 2019

Persistent Large-Scale Pattern with Critters in the Woods

I'm not sure how blogger will handle it, but the loop below has been purposefully designed to run at high speed and to repeat to illustrate three key points about the GFS forecast for the next ten days. 

First, the large-scale pattern changes little with persistent upper-level ridging over the southwest U.S. and the westerly mid-latitude jet to our north.  There are variations in the strength of the ridge and the center of its circulation, but these are relatively modest.

Second, one can see precipitation "pulsing" in the lower right-hand panel, which depicts the surface forecast and includes the 3-hour accumulated precipitation.  This pulsing reflects the influence of the sun, with precipitation increasing and becoming most common later in the day and in the early evening and becoming less common over night. 

Third, as can be seen in the top two images which depict the upper-level pattern, there are some "critters in the woods" in terms of upper-level waves that are in the westerly jet to our north or moving in clockwise fashion around the upper-level ridge.  These smaller-scale features modulate the coverage, location, and intensity of the precipitation. 

Put it all together, and this is a very typical July pattern, as illustrated by the 10-day forecast. 

Personally, I'm already dreaming of September....

Sunday, July 21, 2019

Convection over the Uintas

During periods of weak large-scale forcing in the summer, the mountains play an important role in the initiation of convective clouds and thunderstorms.  Nowhere is this more apparent in our region than over the Uinta Mountains where a visit sometimes makes one feel like they've traveled to another planet.

The photo below was taken from the Gobblers Knob summit at about 10 AM this morning looking east toward the Uintas.  As is often the case, one can see the first cumulus clouds of the day forming over the Uintas.  Often, these clouds grow in depth, producing showers or thunderstorms later in the day. 

I don't know of a study that has specifically examined the influence of the Uintas on convective cloud initiation and evolution, as well as growth into thunderstorms, but I'll speculate here on one of the reasons why the Uintas are so active: their scale.  They are quite high and broad with large expanses of lower elevation terrain to the north and south of their west-to-east oriented spine.  This favors the development of a robust "mountain-plain circulation" which during the day features upslope flow with convergence over the Uintas, as depicted schematically above.  This convergence leads to ascent, which not only helps to trigger cumulus clouds, but also creates a moist environment in which those clouds are not as easily destroyed as they mix with the ambient air through a process known as entrainment. 

The "smoothness" of the Uintas might also help since the large-scale mountain-plain circulation is not strongly disrupted by deep, incised topography, although even in the Alps, the influence of the mountain-plain circulation is often apparent. 

Constrasts between the evolution of convection today over the Wasatch and Uintas are apparent in MODIS imagery from NASA's Terra and Aqua satellites.  The Terra overpass at approximately 11:30 MDT shows extensive cumulus clouds over the Uintas.  In contrast, cumulus over the Wasatch was confined primarily to the central Wasatch, especially the high terrain between Snyderville Basin and Alta. 

Source: NASA
The Aqua overpass at 2:30, shows that the convective clouds became much deeper over the Uintas than the Wasatch.  Note the extensive and continuous anvil associated with a storm over the central and eastern Uintas in the image below, with a cloud free area near the Uinta crest to the east, likely associated with a local cold pool in its wake. 

Source: NASA
Radar coverage in the Uintas is so-so at best, but imagery at the time shows a that precipitaiton was likely falling in the Kings Peak area.

Source: NCAR/RAL
Data from shows numerous lightning strikes today in the Uintas.
It's best not to assume that the forecast you hear on TV applies to the Uintas.  It's a better option to check the National Weather Service site for a Uinta-specific forecast and take low probabilities of thunderstorms seriously.  Review National Weather Service recommendations for backcountry lightning safety at

Tuesday, July 16, 2019

Warmest June on Record Globally

Data released Monday by NASA shows that June was the warmest on record globally (see this Washington Post article).

The time series of Junes during the instrumented record (i.e., back to 1880) is shown below.  One can see the long-term warming trend, as well as the year-to-year variability caused by many factors including the El Niño/Southern Oscillation (ENSO), volcanic eruptions, and other climate-system variations.

I've also added some news items and personal notes to provide some context as to what has been going on over the past five decades.

In 1967, I was born.  Just two years later, and 50 years ago on July 20, 1969, humans walked on the moon in what was a truly audacious human accomplishment.  Although I have no memory of the Apollo program, NASA's space program had a real impact on my interest in science.  I remember, for example, requesting and receiving photographs of the Space Shuttle as a teenager.

In 1975, Wally Broecker published a paper in science entitled Climate Change: Are We on the Brink of a Pronounced Global Warming. In that paper, he wrote,
"A strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide.  By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out.  Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years."
In 1979, the National Academy of Sciences published a report entitled Carbon dioxide and Climate: A Scientific Assessment.  The report is sometimes referred to as the Charney Report since Jule Charney, a giant in meteorology from the mid 20th century until his death in 1981, served as chairperson for the group preparing the report.  That report concluded,
"When it is assumed that the CO2 content of the atmosphere is doubled and statistical thermal equilibrium is achieved, the more realistic of the modeling efforts predict a global surface warming of between 2˚C and 3.5˚C, with greater increases at higher latitudes."
In 1985, I graduated from high school.  Global warming is not something that I recall being aware of.  I began to study meteorology because I was interested in weather forecasting.  However, in my junior year, I took a physical meteorology course taught by Craig Bohren.  In that class, we developed simple analytical models of the planetary energy balance to better understand the theoretical underpinnings of processes that cause the planet to warm or cool.

At the time, as I recall, there was vigorous debate about whether or not we could detect a human influence on climate.  In 1988, Jim Hansen testified in congress about global warming, arguing that the signal of human-caused global warming was now detectable.  A good perspective on this testimony based on current knowledge is available below.

The role of both natural and human caused climate change in recent warming is something I can remember being debated at times in graduate school.   There were a few reasons for this.  First, we were still in the early stages of global warming.  Second, teasing out the warming signal from imperfect observations remained challenging.  And third, our computer models remained relatively rudimentary.  

From 1997-1998, the strongest El Niño on record occurred, pushing global temperatures to what were then remarkable levels (I've labeled this the 1997-1998 Super El Nino above).  Subsequently, temperatures from this period were often used for the start of trend calculations to argue that global warming had stopped or flattened.  

In 2007, I was asked to lead a report on climate change for Governor Jon Huntsman Jr's Blue Ribbon Advisory Council on Climate Change (available here).  Several other Utah scientists contributed.  By this time, the nail was in the coffin concerning whether or not the planet was warming and the evidence for human-caused climate change quite strong.  In that report, we concluded that there was no longer any scientific doubt that the planet was warming and that changes in ice cover, snow cover, and sea level were consistent with this warming.  We also concluded that there was very high confidence that human-generated increases in greenhouse gas concentrations were responsible for most of the global warming during the prior 50 years and that ongoing greenhouse gas emissions at or above current levels will produce global temperature, sea level, and snow and ice changes greater than those observed in the 20th century.

A look a the June temperature record above, as well as what is happening around the planet in recent years, shows that things are playing out largely as anticipated, so it's no surprise to me that we see predominantly high temperature records being set, continued declines in arctic ice, continued declines in glacier ice, and accelerating sea level rise.  

If you don't think this is happening, I'm sorry, but you are wrong.  This is a done deal.  We are already living in a climate that is different than the one that existed in the 20th century and bigger change is coming.  Temperature change is often emphasized, but it is water that will deliver the most severe climate impacts for humans through sea level rise, more persistent drought, more intense rainfall, and other changes to the water cycle (e.g., more precipitation falling as rain instead of snow).

When I was in Innsbruck, I found an exhibition in one of the museums on smoking.  

Someday, articles like the one below will similarly displayed in a museum.  People will look at have the same response that I did about the commercial above.  

"What the hell were they thinking?"

Monday, July 15, 2019

Preparing for Private Sector Employment

According to the American Meteorological Society, the largest employer of meteorologists in the United States has traditionally been the government.  This includes the National Weather Service, military, as well as other agencies such as the Department of Energy.

However, the private sector is growing rapidly.  Last week I attended a workshop sponsored by the National Science Foundation, American Meteorological Society, National Center for Atmospheric Research, Commodity Weather Group, BMS Re US, Millersville University, and Maxar to lay the groundwork for better preparing students for private sector employment. 

Attending such workshops is absolutely critical for university faculty, especially those like me that have spent a great deal of time in the ivory tower.  Although I do some consulting and interact with private-sector companies, the reality is that I've spent most of my career in academia and, as one attendee put it, "the private sector is not an alternative career – academia is the alternative career.

Below are some of my takeaways from the meeting, which I share especially for students:

1. Three “portable” skill sets were strongly emphasized: communications, statistics, and coding.  The emphasis on statistics and coding reflects the private sector attendees, so depending on your interest, you might replace statistics and coding with other portable skill sets.  Note, however, that forecasting is not one of them. 

2. Graduates need something on their resume besides meteorology, such as business, logistics, data science, etc.  This could be accomplished through a minor, internship, 4+1 master's program, etc.  I think I was told this in the late 1980s when I was in school, but it bears repeating. 

3. Many of the positions meteorologists are now taking do not have meteorology in the job title.  Examples include data scientist, customer success specialist, etc.  The meteorologists filling these positions are being hired because of their ability to work with uncertain information, probabilistic data, and weather or climate data. 

4. Most of the positions being filled are not broadcast meteorology or traditional forecast positions.  I repeat.  Most of the positions being filled are not broadcast meteorology or traditional forecast positions. 

Students considering employment in the private sector should subscribe to the American Meteorological Society Board for Private Sector Meteorologists e-mail list, watch some of their webinars, and participate in their mentorship program.  These are accessible here.  In addition, although it is a few years old, there is an excellent presentation by Ken Carey of Earth Resources Technology available here that summarizes many of the opportunities. 

Monday, July 8, 2019

The Dog Days Start This Week

It was wonderful to return to the Wasatch last weekend and find so much water and snow. 

It's been several years since it looked like this in early July (since 2011) and it helped us ease back into the climate of Utah from the wetter Austrian Alps.  Even the Mt. Superior butterfly said hello. 

I missed a fairly remarkable late spring.  The climate summary for Salt Lake City International Airport shows a relatively cool stretch from mid May with considerable rainfall, followed by frequent intrusions of cooler air through early July.  Such intrusions make for much more tolerable weather. 

Source: NWS
That changes this week.  We've had a weak trough move through overnight, providing us with somewhat refreshing air and highs in the 80s today and tomorrow.  After that, the GFS is advertising a very typical July pattern with strong ridging centered roughly on the four corners.  

I'm no fan of 10-day icon based forecasts, but I'll include the one below from to illustrate that we are entering the dog-days of summer.

One should never forget that July is a four-letter word.  

Friday, July 5, 2019

A Pleasant 4th for Some, but Not Others

The large-scale weather pattern over the Northern Hemisphere over the past 10 days (maybe longer but I haven't looked) has featured a high-amplitude flow pattern that one might describe as "wavy."  The slowly evolving nature of this pattern has resulted in persistent ridging over Alaska and the Gulf of Alaska and troughing over the western continental United States and adjoining eastern Pacific. 

The situation in northern Utah on the 4th of July was further influenced by a short-wave trough (dashed line below in the analysis for 0000 UTC 5 July/1800 MST 4 July). 

This led to the development of afternoon showers and thunderstorms that led, in my view, to an incredibly pleasant 4th of July, although admittedly some picnics and outside plans were doused.  Given my disdain for summer heat, that's a tradeoff I'm happy to make.  Looking at the numbers, yesterday's high of 83 and daily mean temperature of 71.5 were the lowest on the 4th of July since 2010 when we only reached 78 for a maximum and the daily mean was 57.  Prior to that, one needs to go back to 1995 to find something cooler.

Not everyone is enjoying this pattern, however.  All-time maximum temperature records were set at several locations in southern Alaska, including Anchorage, which reached 90ºF, breaking their previous record by a remarkable 5ºF.

Source: NWS
Interior Alaska can get hotter than that (Fairbanks record is 99 and the state-wide record is 100 in Fort Yukon), but these are exceptional numbers for the Anchorage area and make for sweaty feet in the Xtratuf fishing boots. 

Thursday, July 4, 2019

And So It Ends

Our nearly six-month residency in the Tyrol came to an end last weekend as we left Innsbruck, spent a night in Munich, and returned home to Salt Lake City.  Our entire time there was like a dream, exceeding expectations in every way.

Having given my last lecture on Tuesday and finished grading on Wednesday, our last two days in Innsbruck involved packing and spending some time enjoying and reminiscing about the scenery and the city.

On Saturday, we departed for Munich.  Six months previously, we unloaded our gear on a cold winter's day and sat on the sidewalk pictured below hoping our landlady would actually show up and give us a place to stay that night (she did and was a wonderful host).  Once again, we were on the street and hoping all would go well, which it did (and this time, Delta didn't lose any bags).  As we did for the trip out here, we packed carefully right to the limit of what Delta would allow with checked bags and carryons.

We spent the afternoon in Munich and did a long stroll through Englisch Park, which is a great urban park.  There is a river that runs through it that has just the right current for a long float, which many were doing due to the heat.  There's even a surf spot.

No trip to Munich is complete without a stop at one of the breweries.  

And for us, a final schnapps.

I've mostly been blogging about our experiences in Tyrol, but from a work perspective, I had a very rewarding experience as well.  I taught three classes, all at the graduate level.  The first was a survey of cool-season (i.e., winter) precipitation, the second was an english writing class, and the third weather briefing (co-taught with one of my University of Innsbruck colleagues).  I probably learned more preparing and teaching these classes than my students did taking them.  What a great experience, and I come hope with increased knowledge of Alpine and European meteorology, as well as materials that I can use in courses at the University of Utah.  I also have new friends and collaborators for future science adventures.

Finally, the Fulbright program really provided a great experience.  I really enjoyed the two group meetings of Fubright scholars and students in Vienna and Strobl as it allowed me to see the remarkable breadth of work being done by the program in areas I am rarely exposed to (e.g., Austrian-American studies).

And with that, our Austrian adventure ends.  The Wasatch Weather Weenies now returns to its regularly scheduled programming.  Has the Steenburgh Effect returned with me?  We will see next winter.