Wasatch Weather Weenies

I have finally returned from beyond the Internet and my "adventures" on the Tug Hill Plateau and along Lake Ontario.  I had a great trip, with the highlight having the opportunity to meet and speak with so many great people.  We're going to have a lot of fun during the field program next winter. If you haven't visited the Great Lakes, do it.  Where else can you find a gorgeous beach like the one below (Southwick State Park) with freshwater?  Yeah, the water this time of year is cold, but absolutely beautiful. Here's a shot from Sandy Island Beach, with an especially humorous mix of summer and lingering winter sign postings.  Those of you venturing out on the pack ice should be well aware that swimming is not allowed and that there is no lifeguard on duty! OK, back to business.  As discussed in the previous post, the Tug Hill Plateau is one of the snowiest areas in the eastern United States.  It lies directly east of Lake Ontario.  Topo...

"Most climbers aren't in fact deranged, they're just infected with a particularly virulent strain of the Human Condition" –John Krakauer, Eiger Dreams: Ventures Among Men and Mountains "Ditto for meteorologists" –Wasatch Weather Weenies I embark tomorrow for a mythical place in the eyes of meteorologists, the Tug Hill Plateau of upstate New York.  Unlike the Eiger, subject of John Krakauer's book ,  there is really nothing topographically imposing about the Tug Hill Plateau.  It rises very gradually to a maximum elevation of about 2000 feet, roughly 1750 feet above the level of Lake Ontario.  It is also covered by dense eastern forests, offering few views.  There are no steep slopes, except for a an escarpment on the east side that rises a few hundred vertical feet and is home to the Tug Hill Plateau's only Alpine ski area, Snow Ridge .   What makes the Tug Hill Plateau so special to meteorologists is snow.  Despite it's mode...

After a very long road, Assessment of Climate Change in the Southwest United States , developed as part of the 2013 National Climate Assessment, will finally be released on May 2nd.  The book contains 20 chapters authored by more than 50 scientists from wide-ranging disciplines.  Along with several other atmospheric and cryospheric scientists, including some from the University of Utah and Utah State University, I helped prepare Chapter 4, which serves as a foundational chapter and describes the current weather and climate of the Southwest. Copies of the book may be ordered from Island Press at http://www.islandpress.org/nca .  Full color PDF and an archive of all the figures used in the book will be available at http://www.swcarr.arizona.edu on May 2nd.  You can get a sneak peak of the Summary for Decision Makers at  http://www.swcsc.arizona.edu/sites/default/files/SWCA_Decision_Makers.pdf .

Amongst the remarkable scientific breakthroughs of the 21st century is the detection of planets beyond our solar system.  Pluto may have been relegated to dwarf-planet status, but the list of exoplanets (i.e., planets outside our solar system) discovered by clever astronomers using the capabilities of the Kepler spacecraft is growing rapidly.   Earth-like planets that could support life as we know it are harder to find, but NASA recently announced the discovery of two so-called habitable zone planets in the Kepler-62 system, Kepler-62-e and Kepler-62-f, as well as a third orbiting Kepler-69.   Source: NASA AMES/JPL-Cal Tech Perhaps could start getting ready now for a Battlestar Gallactica like exodus to one of these planets (preferably without the cylons).  They are only a short 1,200 light year journey.  It's tough to say at that sort of distance whether or not one of these planets is teeming with life and a breathable atmosphere.  It took a w...

This morning's radar loops shows the dramatic influence that the mountains of northern Utah can have on winter storms.  Note the persistent radar echoes that are produced over and upstream of the Stansbury and Oquirrh Mountains (identified by red boxes in the radar loop below) as the northwesterly flow is forced upwards by those mountain ranges. Things are a little more complicated over the Salt Lake Valley and central Wasatch Mountains (ugly oval above).  Here, precipitation develops over the southeast corner of the Great Salt Lake, well upstream of the initial mountain slope.  Lake-effect?  Perhaps.  The contrast in lake and air temperature right now is marginal for lake effect, but it is a juicy airmass, so perhaps it's enough to do the job.  Another possibility is that the funneling of air into the Salt Lake Valley due to the terrain concavity formed by the Stansbury, Oquirrh, and Wasatch Mountains is doing the job. In any event, it's a nice rain...

The cool, intermittently wet pattern over the past couple of weeks has likely provided just a bit of breathing room for water managers in northern Utah, with one more storm to come tonight and tomorrow. We discussed previously the meager snowpack that existed at the end of March .  Not much has changed at lower elevations where much of the precipitation that has fallen in April has either been rain or wet snow that melted quickly between storms.  For example, the Ben Lomond Trail SNOTEL (~6000 feet) bottomed out earlier this month with no real recovery (green line).  This is about a month earlier than their median date of the loss of snow cover (purple line). Source: CBRFC Things look better, however, at some (but not all) upper-elevation sites.  In the Cottonwoods, both Mill-D North (8960 ft) and Snowbird (9640 ft) have gained snowpack this month.  At Mill-D North, they are often losing snowpack this time of year (see purple and blue lines), so that...

Source: Reuters/Brian Snyder There was an article in the Washington Post earlier this week discussing one of the impacts of the budget sequester on the National Weather Service: The furloughing of workers for as little as 4 and as many as 10 days.  The latter would be invoked if NOAA is not allowed to reprogram their budget to cover labor costs. One of the challenges facing the NWS when they furlough is the fact that weather never sleeps.  NWS operations are 24/7.  There is no option for a four-day work week.  Humans are especially critical for issuing and communicating severe weather watches and warnings, including those for tornadoes, tropical storms, and hurricanes.  That being said, NWS forecasters are extremely dedicated and I expect that they will do all they can to ensure this aspect of NWS operations does not suffer.  They will plug many holes in the dike this year, but it is difficult to imagine that this is a "passing storm." The cha...

Utah hasn't had a calendar year during which the statewide average temperature was below the 20th century average since 1993.  We came close in 2011, but still came out above it.  2012, as you probably remember, was the hottest year on record for the state. Source: NCDC I've often wondered if we would ever see another year below the 20th century average, but maybe we have a shot this year.  The first three months of 2013 produced a statewide average temperature that was 2.6ºF below the 20th century mean, making it the coldest January to March period statewide since 1985. Source: NCDC That's a pretty good start, and April has thus far been an up and down month that probably averages out to something that is near the long-term average.  We'll have to see how the rest of the year shakes out.

We have a complicated weather situation over northern Utah today.  As can be seen in the analysis for 1500 UTC (0900 MDT), a 700-mb (crest level) low was centered over northeast San Pete County, with an inverted trough extending northward into southeast Idaho.  As a result, strong contrasts in flow direction existed across the Uinta Mountains and the northern Wasatch Mountains.  Precipitation was concentrated primarily near and west of the inverted trough, although the radar may be unable to see precipitation falling over the Uintas and southwest Wyoming due to blockage and overshooting.   Note how easterly flow extends from southwest Wyoming to the northern Wasatch Front, as was forecast by the computer models yesterday .  This led to a weak downslope wind event this morning from Bountiful through North Ogden.  Note the predominantly easterly flow along the western slopes of the Wasatch at 1500 UTC (0900 MDT).   Source: MesoWest As we...

Once again, winter's icy grip has returned to northern Utah.  Those with the time and energy to get out ski touring today might find some pretty good conditions in the upper elevations, and I'm sure anyone at Snowbird or Brighton have the resorts to themselves.  Lucky bums! The large-scale characteristics of the trough that is moving through today and tomorrow is remarkably similar to the one that moved across Utah last week and brought downslope winds to the northern Wasatch Front (previous posts here and here ).   In particular, as the trough moves across the state, the forecast models call for a surge of cold, easterly flow to push into northern Utah from southwest Wyoming on Tuesday. The devil is in the details, however, and as things look right now, it appears that this event will not be as strong as last weeks as the cold, easterly flow is simply not as deep and strong.  This is a scenario in which we might see stronger winds at the canyon mouths, bu...

In an opinion article in the Sunday Salt Lake Tribune ( Stewart Cautious on Climate Change ), Rep Chris Stewart, newly appointed chairman of the House Sub-Committee on the Environment, argues that “the science regarding climate change is anything but settled” and that “as a leader on these important issues, I will look to ensure that we have conducted a thorough scientific review, then use that information to advocate for reasonable policy decisions.”  As an atmospheric scientist and voter in Rep. Stewart’s district, I agree with both of these statements, but ultimately conclude that the time for action is now (or arguably a few decades ago).   Rep. Stewart is correct that the science regarding climate isn’t settled.  As is the case in any science, there are always limits to knowledge, and scientists are constantly testing hypotheses, collecting new data, and working hard to obtain a greater understanding.   Knowledge is never absolute, and uncertainty is consid...

Craig Patterson's death in an avalanche on Kessler Peak is a difficult reminder to all of us who recreate in the mountains how merciless the mountains can be.  Now is a good opportunity to give thanks to all those individuals who make it possible for us to enjoy a day of skiing, snowboarding, snowshoeing, or snowmobiling in the mountains. These folks really do put their lives on the line every day.   According to the American Avalanche Association , 22 ski patrollers, 13 highway technicians, 6 snow rangers/avalanche forecasters, 2 avalauncher gunners, 5 guides, 1 search and rescue team member, and 2 other individuals have been killed while engaged in avalanche and snow-safety related work in the United States.  Most died in avalanches, although 8 were killed in explosive or gunnery related accidents.  Another will now be added to the list.  Let's hope it is the last. So, keep Craig and his family in your thoughts and prayers, and be grateful for everyone who...

Craig Patterson above Shingle Mill Canyon, Provo Area Mountains Please keep UDOT avalanche forecaster Craig Patterson and his family in your thoughts and prayers.  Craig died yesterday in an apparent avalanche accident while conducting work-related duties on Kessler Peak.  Craig was beloved member of a community of dedicated individuals that enable all of us to recreate in the Wasatch Mountains.  My thoughts and prayers are with Craig, his family, and all of his friends in Utah's snow-safety community.

Source: Tim Garrett, University of Utah University of Utah Atmospheric Sciences Professor Tim Garrett and Cale Fallgatter have developed a remarkable instrument that they call the Multi-Angle Snowflake Camera (MASC) for taking pictures of snowflakes in freefall.  With support from the National Science Foundation and assistance from Alta Ski Area and Daniel "Howie" Howlett, they have been operating the camera for two winters now in the Wasatch Mountains.  Their data shows one of the dirty little secrets of the snow industry – that the majority of snowflakes made by mother nature, even in Utah, are defective.  The are frequently beat up, broken, and covered with frozen cloud droplets sometimes called rime.  The examples above are some of the nicer images they have captured.  Below are some examples of heavily rimed snow crystals. Source: Tim Garrett, University of Utah A great story summarizing their efforts and their significance for improving weather f...

Thusfar, the downslope windstorm forecast issued by the National Weather Service has verified quite well.  They called for east winds of 35–45 mph, with gusts to 75 mph, in the high-wind watch they issued at 2:55 AM yesterday morning.  Peak gusts over 60 mph reported thusfar to MesoWest include: UTPR2: 73 mph (Portable weather station installed by UDOT) Centerville (CEN): 70 mph Centerville (CENWWS): 65 mph Centerville (CENEWS): 64 mph Farmington (AP611): 61 mph As we discussed yesterday, high-amplitude mountain waves of the type producing the current windstorm feature a descending layer of high momentum air, but also a hydraulic jump across which there is often a very rapid decrease in wind speed and, in some cases, a rotor in which there is a circular motion of air about a horizontal axis that leads to a complete reversal of the flow at the ground. Source: Whiteman 2000 There is strong evidence of the hydraulic jump and rotor this morning.  Note in the sur...

Many residents of the northern Wasatch Front recall the major downslope windstorm that occurred on December 1st, 2011, when wind gusts reached more than 100 mph near Centerville.  Discussion of the event from previous Wasatch Weather Weenies posts is available here , here , here , and here .  The latter includes some videos, including a humorous one of some of our students attempting to launch a weather balloon. Downslope windstorms are produced by high-amplitude mountain waves .  In a high amplitude mountain wave, high momentum air from aloft descends rapidly and accelerates on the lee (downwind) side of a mountain range.  The strongest winds typically occur near the base of the mountain, and one can often find a hydraulic jump  in which the strong flow ascends rapidly just a bit further downstream.  A rotor, or an area of reversed flow at the surface, is typically found downstream of the hydraulic jump. Source: Whiteman (2000) Most of us, especial...

Over?  Did you say over?  Nothing is over until we decide it is!  Was it over when the Germans Bombed Pearl Harbor?  Hell no! - John "Bluto" Blutarski (Animal House, 1978) Yup, eventual Senator Blutarski was known for his intellectual insights, but in this case he was wrong.  Nothing is over until Mother Nature says it is over, and she still hasn't closed the door on this winter. The forecast models are bringing a deep trough across the Intermountain West, ushering in colder weather for the first part of the coming work week.  The trough is forecast to be moving across northern Utah tomorrow afternoon. Once again, the change in temperature is an easier forecast than snowfall amounts.  In fact, the difference in forecast precipitation for Alta between the various models is mind boggling.  Here's a summary based on the forecasts initialized at 0600 UTC (midnight) 7 April.  Accumulations are for the period from midnight to...

Post-frontal clouds over the Salt Lake Valley @ 7:30 AM A blustery cold front pushed through the Salt Lake Valley early this morning.  "Cold" in this case is a relative term as the post-frontal environment is still fairly mild. The leading edge of the front was relatively dry.  As can be seen in the 7:00 AM radar image below, northwesterly flow at the surface is running well ahead of the main precipitation band accompanying the front. There are some fairly high returns encircling the KMTX radar site on Promontory Point.  Some of that reflects what is known as the radar bright band , an area of locally high radar reflectivity where the radar beam cuts through the melting layer where snow is transitioning to rain.  Even still, there are clearly some pockets of heavier showers and the possibility of a bit of thunder as the frontal band pushes through the Salt Lake Valley.  That would be a nice way to finish the work week. For those who haven't given up...

The Ben Lomond Trail SNOTEL is the lowest in the Wasatch Mountains at an elevation of only 5829 feet.  It is, however, located in the remarkably snowy Ogden Valley, one of the snowiest lower-elevation areas in northern Utah (see marker A below). It is also a beautiful area, and well worth a trip for either backcountry skiing or cross country skiing at North Fork Park . Looking east from Ben Lomond Peak across the Ogden Valley toward Powder Mountain and James Peak.  The Ben Lomond Trail SNOTEL is on the lower snow-covered slopes in the foreground on this day. In a good snow year, you can find snow in the upper Ogden Valley well into April.  Here's how things looked around the Ben Lomond Train SNOTEL on April 26, 2005.  Keep in mind that this site is below 6000 feet in elevation. This year, however, is another story.  The snowpack at Ben Lomond Trail never reached even half of its average peak, it ripened (meaning it warmed to a constant temperatu...

As reported by several media outlets, including the New York Times , noted climate scientist James Hansen will retire from NASA this week. Hansen is certainly one of the most important climate scientists of the last few decades.  Google Scholar credits him with nearly 35,000 citations and an h-index of 78. The h-index attempts to provide a measure of the productivity and impact of a scholar's published work.  Although it is an imperfect measure, in the atmospheric sciences, values above 20 generally indicate a productive senior scientist and above 30 an exceptional senior scientist.  78 is off the scale.  Hansen's many important papers can be accessed  here . Publicly, Hansen is perhaps most famous for the testimony he gave to Congress about global warming during the summer of 1998, which after a short introduction began with the following statement. "I would like to draw three main conclusions.  Number one, the earth is warmer in 1988 than at ...

Low clouds over the Salt Lake Valley and over the Avenues Breath deep and enjoy the moisture this morning.  Last night's deluge has brought some cool, moist air to the Wasatch Front, giving the Salt Lake Valley a positively Cascadian feel. The upper elevations got some of the white stuff.  Alta-Collins received 8 inches overnight with a mean water content of about 10%.  Not the Greatest Snow on Earth, but it probably will ski just fine.  That snow, along with what fell yesterday, got the Alta-Collins stake back over 100 inches again. Golf weather returns tomorrow.