Tuesday, July 17, 2018

Blast from the Past

The past few decades have been quite exciting for meteorologists as our field, like many others, has been transformed by massive technological change. 

Today I took some time to go through my personal archives from graduate school and finally pitch some stuff that's been collecting dust for years.  It was a good reminder of just how far we've come in the past 25 to 30 years. 

As an undergrad in the late 1980s, the Internet wasn't really yet a thing.  I don't recall using it and I certainly didn't have an e-mail account.  We did not look at weather observations, satellite imagery, radar imagery, or model forecasts online.  That information came via DIFAX charts and you were happy to get what you got.  If you wanted to forecast the weather, you had to go somewhere that had these charts, such as a University "map room", so named because the maps were simply hung on the wall. 

Through the 1990s, DIFAX remained a thing and I spent a lot of time in graduate school in the map room trying to figure out the ski weather in the Cascades.  Here's an analysis from 06Z 20 January 1993, a day that will live in infamy in Seattle.  Note the tightly wound cyclone just offshore, which would continue to deepen, eventually generating damaging winds across the Puget Sound.

A portion of my dissertation examined the fine-scale structure of that storm and why it was so damaging, but I have two strong memories about that day.  The first is that one of my fellow graduate students surfed the Puget Sound.  The second is that we tried to go night skiing after the big blow and it was pretty much a disaster trying to get up to the ski area.  I have no recollection of whether or not the skiing was any good, but it probably wasn't.  It sowed heavily in advance of the cyclone, but as it moved through, marine air flooded into the Cascades and likely created even mankier conditions.  Yet another reason to live in Utah. 

When I started at the University of Washington in the summer of 1989, the first job I was assigned involved plotting cross sections.  This involved plotting profiles of wind and temperature by hand from alphanumeric upper-air sounding data, something that nobody has done in ages.  There was no computer program that could do this at the time.  Below is an example, with a manual analysis of temperature (solid lines) and wind speed into/out of the cross section dashed). 

My oh my how things have changed and for the better.   Eventually the bots will probably take over, but for now, this really is a great time to be a meteorologist.  I don't long for the old days, although I would take my 25-year-old body again in a heart beat. 

Monday, July 16, 2018

Upper-Level Flow Forecast over the Western U.S.

This morning's 500-mb upper air pattern features an upper-level ridge, or anticyclone, centered off the southern California coast.  The anticyclone is zonally elongated, which means stretched in an east-west direction.  The flow at this level roughly parallels the 500-mb height contours, with lower heights on the left, which yields easterly flow to the south of the anticylcone over Mexico and the subtropical eastern Pacific Ocean, and westerly flow to the north over Canada and the Pacific Northwest. 

Such a pattern is not unusual in July, although in this case, the anticyclone is centered west of its climatological mean position over southern New Mexico and the easterlies to the south are a bit stronger than average. 

There are two important smaller-scale features at this level.  The first is a trough in the westerlies over the Pacific Northwest, indicated by a brown dashed line.  The second is a trough in the easterlies over northern Mexico, also indicated by a brown dashed line.  Meteorologists typically call such features short-wave troughs, although troughs in the easterlies are often called easterly waves

The ability to predict the movement and evolution of both the large-scale cyclones and anticyclones, as well as short-wave features, is critical for weather prediction.  During the monsoon, these features play an important role in moisture transport, convective initiation, and precipitation coverage and intensity. 

The loop below shows the GFS forecast for the next 5 days, ending at 1200 UTC (0600 MDT) Saturday 21 July.  Note how the short-wave features "pinwheel" around the anticyclone.  This is a defining characteristic of upper-level waves.  Short-wave features move faster than long-wave features.  The short-wave trough in the northerlies moves over the upper-midwest and amplifies, forming a stronger upper-level trough over the Great Lakes region.  Similarly, the easterly wave moves over the eastern Pacific and amplifies, closing off west of California.  Meanwhile, the anticyclone shifts slowly eastward, ending the loop centered over New Mexico and west Texas. 

The image below is for the end of the loop [i.e., 1200 UTC (0600 MDT) Saturday 21 July] to highlight those key features.  In addition, the position of the anticyclone and easterly wave opens up the potential for the transport of moisture later this week and weekend.  For example, such a pattern is one where the Sierra Nevada could see some thunderstorm activity. 

All of this is based on one model forecast produced by the Global Forecast System (GFS).  Typically the details of the forecast are sensitive to how all these features interact, and this is why meteorologists consult ensembles and multiple modeling systems to try and get a handle on the full range of possibilities. 

Sunday, July 15, 2018

Even Meteorologists Get Burned by the Weather

After an aborted attempt to ski Kings Peak in May (see Uinta Misadventures), my son and I decided we needed to go back this summer and make the summit.  I have lived in Utah for 23 years and incredibly haven't done Kings Peak, so we left Friday afternoon to try and bag it Saturday (yesterday). 

The hike in on Friday evening was as enjoyable as a long slog can be.  The meadows were pretty and the trail dry and fast.  We realized quickly what a folly it had been to try and ski Kings in May with patchy, unsupportable snow on AT gear.  Good golly, what a long approach for what would have been a minimal amount of turns!

Friday night I awoke at 2 AM or so and peered out at wonderfully clear skies.  Sunrise Saturday morning was beautiful. 

However, just visible in the pond reflection are some clouds that were floating about and gave me a little heartburn.  I was mainly concerned about afternoon thunderstorms.  I had anticipated a slight threat of those happening as often occurs in the Uintas, and this was also reflected in the National Weather Service Forecast for the western Uintas issued Friday afternoon. 

We left our campsite around 7:30 am, and already the partly cloud skies were starting to fill. 

Nearing the summit at 9:30 am, it was clear things were going south with showers in many areas, including looking west. 

A bit later, at the summit, it was clear that the 30% chance would "verify" and that things were falling apart sooner than anticipated, although thankfully we hadn't heard thunder or seen lightning.

As we took a summit photo, it was just starting to sprinkle. 

And, looking west, it was clear that things were going to change.

We began our descent.  When we reached the summit, we were the only ones on top and we hadn't passed anyone descending.  On the descent, the line of climbers was long.  We had fortunately brought some layers and rain gear, but others were in true Alpine style with shorts, thin T-shirts, and minimal gear if any.  A few were in sandals.  Kings Peak is a long ways from home when the weather goes south.  We were glad to have brought up some warmer clothes.

Indeed, the rain came in on the descent, and we had steady develop as we descended below Gunsight Pass. 

Fortunately, we got a break before reaching camp.  My son wanted to head all the way out so he could watch the World Cup Final this morning, so we spread stuff out to dry and I caught I quick nap.  We broke camp and began the long slog out, with rain starting again shortly thereafter. 

Really, it didn't rain all that much, but it was enough that portions of the trail turned into a quagmire.  At this point, we kept our heads down and the legs churning. 

All of this is a reminder that Meteorologists get burned by the weather too and that a 30% chance of showers doesn't mean a 0% chance of showers.  On the other hand, I the early development of showers that morning was a surprise.  I consider this a penalty for not paying proper sacrifice to the Gods of Kings Peak.   Clearly that area is cursed for me.  At least we summited and enjoyed a decent view. 

Friday, July 13, 2018

Large Climate Vulnerability at the Proposed Nordic Valley Ski Resort

Nordic Valley is a small ski area near Eden in the Odgen Valley east of the northern Wasatch Mountains.  It has a base elevation of 5400 feet, the lowest in Utah, and a vertical drop of 1000 feet.

The owners, however, have recently announced major expansion plans (see this Salt Lake Tribune article published this morning and this Ogden Standard-Examiner article published on June 25th) that include the installation multiple lifts including a 4.3 mile long gondola from North Ogden and expansion onto 2800 acres of national forest.  The map below is from the Nordic Valley expansion plan web site (https://nordicvalleyproject.com), which unfortunately is oriented so that north is toward the bottom.  The summit elevation would be around 8100 feet, a tad higher than the base of Snowbird and a tad lower than the base of Alta.

Source: https://nordicvalleyproject.com/
There are a host of concerns about the proposed project highlighted in the articles linked above, but let's talk about this from a weather and climate perspective.  This would be a remarkably low elevation ski area for Utah, with a base on the Eden side near the current 5400 feet and, if the map above is to be believed, 4725 feet on the North Ogden side.

In the climate of the late 20th and early 21st century, the area around Eden has been quite snowy for its elevation.  As I like to say, pound for pound it is the snowiest place in Utah.  Just to the north of Nordic Valley, the Ben Lomond Trail Snotel Site at 5971 feet has a maximum median snowpack water equivalent of 19.1 inches in late March.  Observing sites don't exist elsewhere in the Wasatch at that elevation, but I suspect there's nowhere in the range at around 6000 feet that compares to that.  Higher, at the Ben Lomond Peak site at 7688 feet, the maximum median snowpack water equivalent is 37.2 inches in early April.  This is higher than the 24.1 inches at Thaynes Canyon (9247 feet at Park City Mountain Resort) and just a bit lower than the 42.9 inches at Snowbird (9615 feet).  

However, the low elevation makes Nordic Valley the most vulnerable ski area in Utah to climate change.  The graph below illustrates estimates of the fraction of precipitation that currently falls as snow that would instead fall as rain at Wasatch and Oquirrh Mountain SNOTEL sites for every degree Celsius of warming.  By far, the highest sensitivity is the Ben Lomond Trail site, with a 20% reduction for 1˚C of warming, 40% for 2˚C, 55% for 3˚C, and 70% for 4˚C.  Ben Lomond Peak's sensitivity is lower due to it's higher elevation, but it is still larger than at Thaynes Canyon or the Snowbird SNOTEL due to it's lower elevation.  Snowpack sensitivity, not examined here, would probably be higher.  
Source: Jones (2010)

The bottom line is that the new Nordic Valley, even with expansion to the Wasatch Crest at 8100 feet, will still be the must vulnerable Wasatch Mountain ski resort to future climate change.  It is at an elevation where the fraction of wintertime precipitation that falls as snow will be decreasing the fastest and at which vulnerability to wintertime thaws and sublimation losses will be the highest.  

On the other hand, the owners don't seem to be too concerned.  In an interview with the Ogden Standard Examiner, James Colman, the resort manager said,
"There’s been climate change for millennia. There’s no question the Earth goes through cycles, there is climate change, in general the Earth has been heating up. It’s not something I worry about a whole lot myself. We do the best we can to deal with it, to improve our snowmaking, to improve the way we manage the mountain.  
"I just think there are bigger things I have to deal with, personally, that I can have more control over than the climate. I don’t think it’s conclusive, personally, that climate change is human caused. My home in Durango, 10,000 years ago, was under 2,000 feet of ice."

Thursday, July 12, 2018

Thinking of Kikkan Randall and Others Affected by Breast Cancer

Olympic gold medalist Kikkan Randall announced yesterday that she was recently diagnosed with breast cancer. 

Randall is a 5-time Olympian and 13-time World Cup race winner in cross country skiing.  She and Jessie Diggins provided one of the great moments during the 2018 Pyeongchang Winter Olympics when they won the women's team sprint and earned the first Olympic gold medals for a U.S. cross-country skiers. 

Jessie Diggins and Kikkan Randall (right).  Photo: Sarah Brunson/U.S. Ski & Snowboard.
Randall's diagnosis hits home for me as my wife is a two-time breast cancer survivor.  According to the Anchorage Daily News, Randall found two pea-sized lumps in her breast on Mother's Day and will begin chemotherapy this week.  Like many younger women affected by the disease, she is a mother, with a 2-year-old son. 

There is a 1 in 8 chance of a woman in the United States developing breast cancer during her life time.  However, there are also 3.1 million breast cancer survivors in the United States and many reasons to be optimistic.  Increasing survival rates in recent years are believed to be due to catching breast cancer earlier and improved treatments.  Forty percent of breast cancers are discovered by women who find a lump, as was the case for Kikkan, highlighting the importance of performing self exams and taking action to see a doctor if anything unusual is detected. 

I am thinking of Kikkan and everyone who is affected by breast cancer today.  Be vigilant, perform self exams and screenings as recommended by medical professionals, and keep the faith. 

Wednesday, July 11, 2018

Salt Lake's July "Human Misery Index" Is Climbing

Human comfort is strongly influenced by a number of factors including temperature, humidity, cloud cover, and wind.  For the purposes of this post, I am going to focus on one that I consider to be especially relevant to human comfort in the Salt Lake Valley, the minimum temperature.

In particular, I am going to declare 70ºF as a critical threshold in comfort, with minimum temperatures below that value generally yielding reasonable comfort, whereas minimum temperatures above that level generally yielding uncomfortable sleeping conditions.  Going a step further, I'll define the human misery index in Salt Lake City as being equal to the number of days with a minimum temperature at or above 70ºF. 

Looking at historical data for the Salt Lake City Area stretching back to 1874, we see a rapid change in the July human misery index beginning around Y2K.  In particular, around that time a clear upward trend began and we have had five Julys since 2007 with 15 or more days with a minimum at or above 70ºF, something that never happened previously. 

Source: NOAA Regional Climate Centers
So, if you think that nighttime comfort around here ain't what it used to be, you are right.

This trends has a variety of implications for everything from human and environmental health to electricity demand. Cooling degree days in July, for example, show a gradual increase for the periods prior to 2000, but since then, we've been experiencing a new normal, with the average number of days clearly higher and several years with values near or above 600.  

Source: NOAA Regional Climate Centers
Thus, in addition to growth and increased use of air conditioners, a hotter valley climate is also contributing to increased electricity usage.  

Development and associated urban heat island effects, global warming, and recent circulation patterns are possible contributors to these recent trends, although I am unaware of a study that has attempted to quantify the contributions of each of these effects.  I suspect it is likely that that both the urban heat island and global warming are contributing significantly to the upward trends.  It is possible that instrumentation moves and local conditions around the airport might also be contributing.  

Personally, I'm starting to find all of this quite depressing.  Mother Nature might perturb the jet stream some summer to give us an unusually cool July, but it is difficult to imagine the long-term trend not being towards an even hotter future.  By the end of the century, Salt Lake could be the new St. George.  Good luck with that.   

Note on Comments:

I usually try to keep up with comments, but for some reason, blogger is no longer sending me an e-mail when you comment.  As a result, I've been missing your comments.  Please keep commenting.  I'm hoping to get this fixed and to be better about responding.  

Sunday, July 8, 2018

Observations from Mt. Baldy and Hidden Peak

Beating the heat, I did a quick climb of Mt. Baldy and Hidden Peak this morning, giving my knees a break with a descent via the Snowbird Tram.  Some observations.

I was on the summit of Mt. Baldy at about 9:45 am.  The view to the east was a scene from the Great Smokies and a good example of how smoke can become trapped in valley cold pools that develop overnight. 

We've been fortunate in the Salt Lake Valley to have not been in the smoke plume except for a brief period late Thursday night and Friday. 

For snow lovers, I found the patch below at about 9400 feet in an area where contributions of artificial snow to the snowpack would probably be small to non-existent. 

I'm guessing it is the lowest remaining snow in the Wasatch.  Prove me wrong...

Finally, a little comparison of the snowpack on this date (8 July), compared photos I've taken in July the previous two years.  The situation this yea is pretty grim.  Just a few patches to be had on the north side of Twin Peaks and in the usual spots in Upper Hogum. 

Last summer was preceded by a much better snow season and it shows.  The photo below was taken 22 July 2017 when you could almost send it down the Pipeline couloir and coverage in upper Hogum was more extensive. 

If we go back a bit further, to 26 July 2015, one find a situation in which there was virtually no snow except in a few very small pockets. 

Will we get to nearly snow free by the end of the month and will we have a snow-free Wasatch before the start of the next snow accumulation season?  Time will tell. 

Friday, July 6, 2018

Campfire Weather and Bad Air Quality Are Here

Ah, July.  Triple digit temperatures, wildfires, and bad air quality.

So far this month, the Salt Lake Valley has escaped the smoke, but that all changed overnight and residents awoke this morning to a smoky scene.

Yes indeed, the smell of campfire is in the air, sadly without the smores.

This is an educated guess based on the HRRR-Smoke and regional analyses, but I suspect this smoke is from origins to the south, including the West Valley Fire north of St. George, rather than the Dollar Ridge Fire to the east or the Hogan Fire to the west.  With more digging, perhaps one of you can nail it down for me.

Regardless, the PM2.5 levels in the Salt Lake Valley have risen.  The trace from Hawthorne Elementary tells the tale.  Of course, the worst air quality of the past 5 days occurred at 11 PM on the 4th of July when PM2.5 peaked at 64.7 ug/m3, which is at unhealthy levels.  The joys of fireworks.
Source: DAQ
After a recovery yesterday, however, the smoke moved in after about 10 PM last night, with PM2.5 levels thereafter hovering just over 40 ug/m3, which is unhealthy for sensitive groups.

The Purple Air network appears to have a good handle on this event and its spatial structure.  PM2.5 at about 8:40 AM this morning appeared to be highest along the east bench and lowest in the West Valley.  If one peaks along the screenshot bottom, you can find the highest values in Utah County.  

In fact, one can find some stations down there with values at the upper-end unhealthy levels.  Such variability is not uncommon with smoke plumes.

The NWS forecast high for this afternoon at the Salt Lake City International Airport is 102˚F.  If there was no smoke, we would expect the combination of a high-angle July sun, high temperatures, and the usual urban pollution to lead to high ozone.  This has happened consistently the past 5 days, with the highest values reaching unhealthy for sensitive groups yesterday afternoon.

Source: DAQ
Ozone is produced by photochemical reactions that occur in sunlight between pollution and naturally occurring gasses in the atmosphere.  This is one reason why ozone typically peaks in the afternoon (give or take a few hours).  The chemicals in wildfire smoke typically up the ante and lead to more elevated ozone levels.  We will probably see ozone levels in the unhealthy for sensitive groups level this afternoon, but higher values are possible and could combine with elevated PM2.5, if the smoke lingers.

Addendum @9:05 AM:

I realized after posting this article that the term "campfire weather" in the title might be misconstrued to suggest that it's a good time to have a fire.  That is definitely NOT the case.  In this instance, it simply means that it smells like a campfire. 

Addendum @9:10 AM:

DAQ reporting smoke may be from Dollar Ridge Fire and there are some winds in surface mesonet data over the region with an easterly component.  Thus, my gut on this could be wrong.  Comments from sleuthing types out there appreciated as I need to get some work done...

Thursday, July 5, 2018

The Fickle Relationship Between Rain and Fire

Everyone is hoping for a major dousing of rainfall for the Dollar Ridge Fire raging east of Strawberry Reservoir.

Some sprinkles have been noted in the vicinity today, as reported, for example, by Jed Boal of KSL News.

However, sprinkles are not enough and they may do more harm than good because of the fickle relationship that exists between rain and fire.

A best-case scenario for taming the wildfire and reducing (or eliminating) extreme and erratic fire behavior is a situation with high relative humidity, cool temperatures, light wind, and steady precipitation. 

On the other hand, while sprinkles may temporarily increase the relative humidity, they can cause more harm than good by initiating gusty winds or microbursts that lead to erratic or extreme fire behavior. 

That is my concern today.  The morning sounding from the Salt Lake City International Airport shows remarkably dry low levels ripe for the production of strong microbursts. 

Source: SPC
 Meteorologists use a variable, known as Downward Convective Available Potential Energy, or DCAPE, to quantify the amount of energy that may be produced by cold, dense air produced by evaporation.  This morning's sounding had a DCAPE of 860 J/kg, which is quite high.  In other words, conditions are ripe for microburst winds. 

The latest radar shows scattered, but weak cells in the fire region.  These might produce some sprinkles or light rain, but it will be brief and probably accompanied by gusty winds. 

So, if you are praying for rain, be specific.  Sprinkles are not good enough and you could be causing more harm than good.  We need a prolonged period of rainfall or, if that's not not possible, a period of cooler weather with higher relative humidity, weak winds, and no microbursts.  

Wednesday, July 4, 2018

Dollar Ridge "Time Lapse" from Mt. Nebo

Intensification of the Dollar Ridge fire was very evident today as I descended from the summit of Mt. Nebo.  The photos below are in chronological order and were taken from 11:21 AM to 1:52 PM.  This is a very common occurrence as temperatures climb and the the so-called boundary layer, in which thermals and turbulence generated at the Earth's surface occur, deepens.  Note the formation of pyrocumulus clouds as well.  Sadly I only had the cell phone. 

Portable weather stations at about 9000 feet near the fire showed temperatures in the 70s, relative humidities near 10% and winds gusting to 30 mph.  It doesn't get much worse than that.  The low humidity was very apparent on my hike as I consumed 64 ounces of water, despite an early start, and still returned to the trailhead completely parched. 

Fires and fireworks should simply be avoided this holiday week.

Tuesday, July 3, 2018

A Bad Independence Day to Play with Fire

I'm not fan of the tomfoolery that occurs on and around the Independence Day holiday.  Most years, the potential for human-sparked wildfire is high enough, but this year, things are especially bad.

The latest forecast from the USFS shows extreme fire danger across most of Utah, with only the strip along the Idaho border in the low category. 
Source: USFS
Basically, most of Utah is a tinderbox.  Meanwhile the National Weather Service has nearly the entire state in the pink, indicating a red-flag warning that for most of the state currently extends through midnight tonight and reflects a combination of heat, low humidity, and strong winds that may be persistent or gusty. 

Source: NWS
Even if we are not under red-flag conditions tomorrow, the state is still a tinderbox.

The potential for disaster is well illustrated by the Dollar Ridge Fire southeast of Strawberry Reservoir, which produced smoke that was clearly evident in yesterday's MODIS imagery. 

Source: NASA, USFS Geospatial Technology and Applications Center
According to the National Interagency Fire Center, the Dollar Ridge Fire began on private property and is believed to be human caused.  It was first reported at 1 PM on July 1st.  My son and I actually saw the initial plume while on East Castle around that time.  It quickly burned nearly 7,000 acres by that evening.  The latest news reports suggest that it has now burned 30,000 acres.  I've yet to confirm that at the National Interagency Fire Center web site, but it could be it just hasn't updated yet.

The bottom line is that we have met the enemy and it is us.  Let's hope we don't have a strong nominee (or nominees) for a Darwin Award when the holiday week comes to an end.

Sunday, July 1, 2018

Clean Air and Incredible Views Never Felt So Good!

What an airmass!  After two weeks of nearly continuous travel, what a treat it was to climb the East Castle today with about the most pristine airmass you will find in Utah in the summer. 

My trip to Beijing was fun and rewarding, but after breathing the smog there, clean air and incredible views like those pictured below never felt so good. 

The Clean Air and Water Acts have paid huge dividends for this country. The Clean Air Act became law in 1970 and was passed by the Senate without a single opposing vote. Let me repeat that. One of the most sweeping and important environmental protection laws passed the Senate without opposition. George H. W. Bush sought to strengthen the act and amendments were passed by an 89-11 vote in the Senate during his presidency. At the time, Mitch McConnell voted for the amendment and said "I had to choose between cleaner air and the status quo. I chose cleaner air."

So do I. The view that we have a choice between a healthy environment or a growing economy is a false dichotomy. Clean air, clean water, a vibrant economy, and high quality of life go hand in hand. 

I look forward to a clean energy and clean air future.