A Rant about the End of Daylight Savings

Source: whimquarterly.com

Every year in the spring, there is a vocal minority that complains about daylight savings time.  Some don't like the "hangover" from the time change.  Others think it is some government conspiracy.

I think these people are all nuts.

The problem with daylight savings time isn't that it starts, but that it ends.

If I were King, I would make daylight savings time permanent for the entire calendar year.

Why do we even bother with standard time?  Who cares if the sun is at its highest point around noon? What I care about is recreation, and I like it when the light lingers after I get home from work.  I can do that this time of year when we are on daylight savings time, but not standard time.

Yesterday I was out for a walk in the foothills until almost 6:30 PM and it was light out.  How enjoyable.  Next week, it will be a walk in the dark.  Why must we suffer in this fashion?

What are the arguments for going on daylight savings?  One is school safety, but kids get up too early anyway.  Let's shift the school day instead.  Let them sleep in.

It's time to put an end to standard time and make daylight savings time permanent year round.

A Blessing, but Hopefully Not a Curse

The last gasp of this week's storm is motoring through the Salt Lake Valley this morning in the form of lake-effect rain and snow showers.

The early season snow is partly a blessing for upper-elevation north-facing terrain where it is likely to linger and serve as base for our next storm.  It could, however, be a curse as well. The Utah Avalanche Center reported the first avalanches of the year yesterday, all triggering on weak, faceted snow left over from the storm earlier in October.  That weak snow probably won't strengthen much the next few days and we now have a thin snowpack on other aspects.  

The ideal situation for a strong snowpack at the beginning of the season is to have it start snowing and not stop until the snowpack is deep enough to prevent the formation of weak, faceted crystals near the ground.  The worst case scenario is to have a thin snowpack linger and weaken, which often happens after storms in October.  This creates plenty of booby traps for Wasatch skiers when it finally starts to snow again.  A prime example of this occurred on November 13, 2011, when there were multiple human-triggered avalanches, including one that killed Jamie Pierre.  

When the snow does start to fly again, be careful and remember that resort terrain needs to be considered backcountry during the early season.  

Better than Expected...I Think

This time of year when ski area and snow safety operations are still a few weeks away, we rely on a very small number of automated stations to provide us with information on snowfall in the mountains.  In addition, automated snow-depth gauges tend to be a bit sketchier when the snow depth is low.  Therefore, there's more uncertainty than usual in determining how much snow fell last night.

The Snowbird SNOTEL came in with about 1.3" of snow-water equivalent after temperatures dropped to near 32ºF.  The automated snow depth sensor was fluctuating around an inch prior to the storm, and currently measures 13 inches after a peak at 14 inches.  

Alta–Collins recorded a bit less.  The total snow depth increased from 12–15 inches prior to the storm (pick your favorite, note that this depth sensor read 6 inches when the ground was bare a couple of weeks ago, so deduct 6 for a snow depth estimate) to 24 inches at last observation.  The interval stake recorded 10".  

So, let's call it something like 10–12 inches in upper Little Cottonwood.  If you want a better estimate, you'll just need to go up and measure it yourself!

Much of that snow fell late yesterday and last night.  The storm structure and dynamics have since changed and an interesting aspect of the storm this morning is the persistence of echoes along the Alpine ridge between Little Cottonwood and American Fork Canyon.  

In particular, note that the radar echoes are stronger and more persistent from about Lone Peak to the Pfiefferhorn and weaker and less persistent in upper Little Cottonwood including Snowbird and Alta.  We sometimes see this in southwesterly flow when shallow orographic clouds are generated by forced ascent from the Utah Valley over the Alpine Ridge.  The photo below, which looks southward toward Lone Peak from the University of Utah, shows some of the shallow orographic clouds being generated by the southwesterly flow over Lone Peak.  

Red Sky at Morning...

Salt Lakers enjoyed a spectacular sunrise this morning, but as the old saying goes, red sky in morning, sailors take warning.  The winds of change are upon us and our long run of sunny fall weather is coming to an end.

Sowing the seeds for this change is a trough that dug rapidly and deepened over the Great Basin overnight last night.  This is a classic case of what meteorologists call downstream development in which the ridge over the Gulf of Alaska amplifies followed by trough amplification over the western U.S., as shown in the 500-mb geopotential height loop below which covers the 48-hour period ending at 1200 UTC (0600 MDT) this morning.

The trough amplification has led to gusty winds over much of Utah.  Over the past 6 hours, peak gusts reported to MesoWest include 61 miles per hour at Cedar City, 54 miles per hour at Stockton Bar (Tooele Valley), and 52 miles per hour at Dugway Proving Grounds.  The deepening low has also generated a modest downslope windstorm with easterly flow observed along the Wasatch Front north of Olympus Cove.

Source: MesoWest

Some of the strongest winds thus far have been observed at the University of Utah, which experienced a peak gust of 39 miles per hour at 7:40 AM this morning.

The models the past couple of days have been all over the place with regards to the timing, distribution, and amount of precipitation that will accompany the trough as it moves across Utah between now and Wednesday afternoon.  I feel like that computer in WarGames, which concludes after playing many rounds of simulated thermonuclear war that the only winning move is not to play.

Source: WarGames

Let's just go with periods of mountain snow beginning late today through Wednesday with a total accumulation of several inches in the upper Cottonwoods.  The weather in the valley will be unsettled and much cooler than we've experienced over the past week.  The benches may even see some flakes on Tuesday and Wednesday.

Declining Air Quality

Downtown Salt Lake City from the Avenues Foothills, 5:24 PM October 24, 2013

Over the past few days, PM2.5 levels in Salt Lake City have been gradually climbing.  They reached a maximum hourly value of 27.3 ug/m3 yesterday afternoon and the 24-h average reached at 16.2 ug/m3 this morning.  That's below the National Ambient Air Quality Standard, but still high enough to put us into the "Moderate" air quality category.

Source: Utah Division of Air Quality

Such elevated values are unusual but not unheard of.  The plot below shows the percent of days that PM2.5 exceeded 17.5 ug/m3 and 35 ug/m3 versus the week of the year from 1999–2011.  We currently sit in week -10 (negative implies weeks prior to the first week of January).  From 1999–2011, days with PM2.5 (presumably 24-h average) exceeding 17.5 ug/m3 represent about 2% of the days (probably 2 of the 84 days that make up all the week -10s during the 12 year period).  Note that as I write this we still haven't hit 17.5, but we are close and perhaps we will get there today.  

Source: Dave Whiteman, University of Utah, http://home.chpc.utah.edu/~u0453210/PM2.5/PM2.5.html

An interesting aspect of the graph above are the occasional episodes with PM2.5>17.5 or > 35 outside of the inversion season.  Those are likely related to either fires or blowing dust events.  That's certainly not the case this week.  We're simply seeing a buildup of primary and secondary pollution from emissions in the Salt Lake Valley.  In this case we've met the enemy and it is us.  

Subtropics to Visit Alaska

Given that the weather in Salt Lake continues to be dominated by the passage of just some occasional "cirrus monotonous", I'm looking elsewhere for some interesting weather and the winner is Alaska. 

Things are setting up for a major surge of moisture into south central Alaska.  The 0600 UTC GFS shows the setup with a pronounced upper-level short-wave trough approaching the state from the southwest at 1200 UTC 28 October (4 AM Alaska time Monday morning) and low-level fetch extending from the tropics over the Gulf of Alaska and into the state's interior.

What is most impressive about forecasts of this event is the penetration of moisture into the high latitudes.  Over interior Alaska and the Yukon, for example, the forecast precipitable water (a measure of the total water vapor in the atmosphere) reaches 0.5 to 0.75 inches at 4 AM Monday morning (solid contours below).  Such values aren't all that unusual over the Gulf of Alaska, but are unusual for this time of year in the Alaskan and Yukon interior.  In fact, in some areas they have never been observed over the past 30 years during the 3 week period centered on Monday (color fill below).

Source: NWS

Precipitation over mountainous regions is not only influenced by the amount of moisture, but also the transport, which is related to the wind speed. As shown below, there is an elongated filament of high moisture transport (solid lines) known as an atmospheric river extending from the subtropics into the Alaskan and Yukon interior.  The values forecast over a wide region of the interior haven't been observed over the past 30 years during the 3 week period centered on Monday (color fill below - see red area).

So, this has the potential to be an unusual weather event for late October over southcentral Alaska, especially the interior.  There is some uncertainty with regards to the forecast, however, so, as noted by the National Weather Service in their discussion this morning:

"THE FULL EXTENT OF THE IMPACTS ARE UNKNOWN AT THIS TIME BUT SHOULD BECOME MORE CLEAR IN THE COMING DAYS."

Fear and Loathing in Salt Lake (about Pollution)

Pollution over the Salt Lake Valley as viewed from above Big Cottonwood Canyon, October 23, 2013

Paraphrasing Hunter S. Thompson seems appropriate today as my fear and loathing of the wintertime inversion are on the rise.  It's October and we are already seeing pollution in the valley, as one can plainly see looking out the window or in the photo above.  October!  PM2.5 concentrations in the Salt Lake Valley are not as high as they reach during winter inversions, but they are elevated, reaching about 18 ug/m3 yesterday.

Source: DAQ

Perhaps it's just me, but it seems like we are more susceptible to events like this than we were 10–15 years ago.  We do have a big ridge in place, but perhaps emissions have reached a point where we're seeing a creep of the pollution season into earlier in the fall and later in the winter.  Events are infrequent enough to make trend detection difficult, but perhaps an adventurous reader out there can dig into the numbers and see if this hypothesis has merit.

It's Going to Be Close

Utah has not has a year with a statewide average temperature below that of the 20th century mean since 1993.

Source: NCDC

That is quite a run and it reflects a warming climate.

However, so far this year is very close to that 20th century mean, so the next several weeks will determine if the streak will continue.  In northern Utah, we had a remarkably cold January followed by a remarkably hot summer.  The extremes in southern Utah haven't been quite so pronounced.  When you put all of this together, the statewide average temperature for January–September is just a shade (< 1ºF) above the mean for the same period during the 20th century.

Source: NCDC

If we can eke it out, that would give us 20 consecutive years with statewide average temperatures above the 20th century mean.  If Utah's climate wasn't changing and remained equivalent to that of the 20th century, the odds of that occurring are about 1 in a million (basically, the same as flipping a coin and getting a head 20 times in a row).  Such a long run of above average annual temperatures is yet another indicator that the climate of the past couple of decades is not the same experienced by Utah residents during most of the 20th century.

Mysteries of Rime Mushrooms

Source: American Meteorological Society

Congratulations to University of Utah Atmospheric Sciences Professor Dave Whiteman and Alpinist Rolando Garibotti who have the cover article of the latest Bulletin of the American Meteorological Society, which explores the characteristics and formation mechanisms of rime mushrooms.  Rime mushrooms are mushroom-shaped formations of hard ice that form on mountain summits and ridges.  They are especially prevalent in Patagonia and other maritime alpine regions, where they frequently pose a challenge for mountaineers.  Click here to access the article, which should be publicly accessible.  Although in a technical journal, the article is quite readable and contains some great photos.

A Ginormous Ridge

Meteorologists in Utah can take some time off as a ginormous ridge will dominate our weather through the week.  Below is the 12-hour forecast from last night's North American Ensemble Prediction System (NAEFS) showing the situation this morning, followed by the 120 hour forecast valid at 6 PM Friday.  There's very little change in the overall pattern with a high amplitude, long wave ridge firmly ensconced over the western U.S.

Source: NWS

Source: NWS

Looks like a good week to be in southern Utah if you are so fortunate.

A Harbinger of Things to Come

Looking south from the Avenues Foothills, 1250 MDT October 19, 2013

Although we are not yet in the inversion season, we are now nearly a full month past the fall equinox, days are shorter than nights, and the sun is getting low on the horizon.  As a result, we're simply not able to mix out the air over the Salt Lake Valley very vigorously, and the net result is a touch of smog.  The sounding taken from the Salt Lake City airport yesterday afternoon shows that the surface-based mixed layer extended to about 750 mb (~8500 ft), where a stable layer basically put a "cap" on the valley atmosphere.  The base of that cap was very near the visual top of the densest smog in the photo above.

Source: SPC

The difference between yesterday and a full blown wintertime smog event is the height and strength of the inversion or stable layer.  Yesterday's stable layer was fairly high, so pollutants were dispersed through a fairly deep layer and there was some transport of air through mountain passes and other gaps.  The stable layer was also weak, so there probably was some exchange of air between the valley and the cleaner airmass further aloft.

With a weak upper-level trough approaching last night and passing later today and tonight, I suspect we  see enough flow and cooling aloft to bring an end to this temporary smog event.  Nevertheless, it is a harbinger of things to come.  

Melting and Rotting

High country snow on north facing aspects above Mill Creek Canyon, October 18, 2013

As so often happens in Utah during October, and early season snowstorm is followed by an extended period of splendid fall weather.  The long-range forecast models suggest that the dry weather we've experienced the past couple of days will persist for at least several days more as both the GFS ensemble (upper left panel) and the ECMWF ensemble (lower left) keep us under the influence of a high amplitude ridge through the middle of next week.

Source: NWS

Even longer range forecasts suggest that this dry weather may continue even longer, although we'll have to see if that comes to fruition.  One thing is certain, the snow that currently exists on south, west, or east facing aspects is toast.  The $64,000 question is what will happen to the snow on upper-elevation slopes facing the northern half of the compass.  It's tough to melt snow this time of year on those aspects.  Will that snow facet and weaken?  That's something to ponder and keep in mind when the snow starts to fly again.

Great Storm Anniversary

Editor's Note: Special thanks to Jeff Massey for contributions to this post.  

Today marks the 29th anniversary of one of the largest snowstorms to hit the Wasatch Front.  It desperately needs a name, but to my knowledge one hasn't been coined, so we'll just call it that Great Storm of October 1984.

A brief analysis of the Great Storm was produced by David Carpenter and published in the journal Weather and Forecasting in 1993 (Carpenter 1993).  David is now the meteorologist-in-charge at the Rapid City National Weather Service Forecast Office and recently made headlines for his office's dedication to public service when a huge blizzard hit western South Dakota during the federal government shutdown.

In the Salt Lake Valley, the Great Storm was a beast, producing 18 inches at the Salt Lake City airport, 27 inches inOlympus Cove, and 25 inches in Cottonwood Heights.  The heaviest accumulation was along the east bench, whereas there were locations in the western and southern valley that received no snow.

Storm total snowfall for 17–18 October 1984.
Source: Carpenter (1993).

Carpenter (1993) suggests that most of the snow fell from 0030–1830 UTC 18 October (1830 MDT 17 October–1230 MDT 18 October) and primarily the result of lake effect.  It is a shame that there was not meteorological radar operating in the Salt Lake Valley at the time to take a closer look at the event as this would surely make it the largest valley lake-effect event in the past 30 years if not in the entire historical record.  In any event, the Great Storm still stands as the largest 24-hour snowfall ever observed at the Salt Lake City airport.  All that snow fell while most of the trees in the valley still had leaves, creating quite a mess of downed power lines.

Carpenter estimated lake temperatures to be near 10ºC during the event.  Temperatures of the Great Salt Lake tend to track very close to the 7-day running mean temperature at the airport.  While I don't have access to lake-temperature data during this period (it might exist, but I'm being lazy), the week preceding the storm features temperatures near 68ºF (20ºC) on the 13th followed cooler weather.  In the three days preceding the event, temperatures fluctuated from near 32ºF (0ºC) to about 50ºF (10ºC).

KSLC Temperatures October 1984.  Courtesy Jeff Massey.

Thus, I'd go with a temperature of 10ºC or perhaps a bit lower.  Surprisingly, this is not unusually high. The climatological lake temperature for mid October is about 14ºC.  Thus, the extreme nature of this storm cannot be blamed on an unusually warm lake (note: the lake size, however, was quite large as during this period the lake level was near its historical high).

However, the event did feature the passage of an especially cold upper-level trough.  As shown in the looop below, 500-mb temperatures dropped to near -30ºC after 0000 UTC 18 October when the lake-effect raged.  At 700-mb, temperatures dropped to about -11ºC, which is not too shabby either.

500-mb and 700-mb analyses for the Great Storm.  Courtesy Jeff Massey.

There are, however, many cold troughs that come through Utah, generate large lake-atmosphere temperature differentials, and don't generate any lake effect.  The triggering and organization of lake effect depends on smaller-scale processes that we are just beginning to understand.  It appears that the key ingredients were all in place for the Great Storm, but a lack of radar data and surface observations precludes a careful analysis of the small scale processes that made it such a huge event.  We're just going to have to hope for a repeat.

The OWLeS Field Program: Adventures on the Tug Hill Plateau

Today marks the first day of our field activities for the Ontario Winter Lake-effect Systems (OWLeS) field program.  Two of my graduate students, Leah Campbell and Peter Veals, arrived in Syracuse, NY last night and will be installing equipment over the next several days.

OWLeS (yes, lower case e) is a National Science Foundation sponsored field program examining the formation mechanisms, cloud microphysics, precipitation dynamics, and terrain enhancement of lake-effect systems (http://www.owles.org).  We are specifically examining "short-axis" lake-effect systems that form when the wind flows across the long axis of Lake Ontario, "long-axis" lake-effect systems that form when the wind flows along the long axis of Lake Ontario, and the enhancement of long-axis lake-effect systems over the Tug Hill Plateau.

Participants include the University of Utah, University of Wyoming, University of Illinois, SUNY Oswego, Hobart and William Smith Colleges, Millersville University, Penn State University, University of Alabama in Huntsville, SUNY Albany, and the Center for Severe Weather Research.

My group is primarily interested in the enhancement of snowfall over the Tug Hill Plateau, which gradually rises as much as 1700 ft (500 m) above Lake Ontario.  The summits of a few peaks in Vermont, New Hampshire, and Maine may get more snow, but the Tug Hill Plateau probably provides the largest contiguous area averaging 200 inches of snow or more in the northeastern United States.  Observations from the area are fairly sparse, but volunteer National Weather Service spotters provided fairly detailed data during the winters of 2003/04–2005/06.  During this period, an annual average of more than 200 inches fell from Osceola on the south side of the Tug Hill Plateau (236 inches) to Barnes Corners on the north side (209 inches).  North Redfield, widely regarded as the snowiest regular measuring location on the plateau, averaged 254", nearly double that observed in Sandy Creek just to the west (138 inches).  There are no regular observations taken over the highest portion of the plateau.

Snowfall on the Tug Hill Plateau supports an important winter-sports economy and the area is well known for snowmobiling and cross-country skiing (slopes steep enough for alpine skiing are limited, but Snow Ridge ski area operates with a 450 foot drop on the eastern escarpment).  Paul Fancia operates NorthernChateau.com, which provides access to weather data and several snow cams in the area, and sent me the video below showing a healthy snowpack on the tug.

The map below summarizes some of the equipment that we will have in the field.  MicroRainRadars (MRR) operated by SUNY Albany and the University of Utah will continuously collect vertical profiles through clouds and storms from this week through the end of February at coastal, lowland, upland, and high plateau sites.  During the field phase (5 December 2013–29 January 2014) we will also continuously operate snow study stations (precipitation and snow data) at the lowland and upland.  During Intensive Observing Periods (IOPs) examining long-axis lake-effect systems and enhancement over the Tug Hill Plateau additional instrumentation will be deployed including the Millersville University Profiling System (upper-air soundings) and the University of Alabama Huntsville Mobile Integrated Profiling System (profiles of wind and cloud structure), both of which are mobile but will operate at times near the lowland site.  Our University of Utah team will also collect upper-air soundings at the upland site.

Finally three Center for Severe Weather Research Doppler on Wheels (DOW) radars will peering into the storms and the University of Wyoming King Air Research Aircraft will collect radar and cloud particle information in the sky.

Center for Severe Weather Research DOW6

University of Wyoming King Air. Photo Credit: Vanda Grubišić

The observations collected by all of these instruments will allow us to examine how and why the characteristics of storms change from Lake Ontario to over the Tug Hill Plateau.  They will also allow us to improve computer simulations of lake-effect precipitation, leading to better forecasts.

A number of local residents have helped to make all of this possible.  We look forward to working with them and leaning about Tug Hill snow this winter.

The Holladay Haze Pool

A phenomenon that I frequently see from the Avenues on cool mornings is a pronounced pool of haze when I look southward over the Holladay and Cottonwood Heights area.

Here's a closeup showing a fairly distinct northern edge.

For such a haze pool to form, one typically needs high relative humidities, so a cool morning after a storm is best.  I've always assumed that the northern edge of the haze pool lies at the southern edge of the outflow from Parley's canyon.  There is some evidence supporting this view in this morning's MesoWest observations.  Note in particular the 15 knot exit jet near Parley's Canyon, whereas the flow is weaker to the south in Holladay and southern Olympus Cove.  In addition, the outflow from Parley's canyon is warmer (39ºF) and drier (RH=64%, not shown) compared to the airmass over Holladay and southern Olympus Cove where it is cooler 30–36ºF (RH=87–100%).

Source: Mesowest

Haze typically needs a relative humidity of at least 70% to form, so this temperature and humidity contrast is consistent with northern boundary of the haze in the photos above.  In some instances, the outflow from Parley's may be colder than the air to the south, but in this and other cases with a visual haze pool, I suspect there is a cold pool over the Salt Lake Valley that is simply scoured out by the Parley's outflow.

There are also times when the outflow from Parley's canyon curves southward and then eastward toward the Wasatch near the Cottonwood Canyons, forming what is known as the "Sandy Eddy."  This eddy results in upslope flow in the Cottonwood Heights area.  Although such flow is not evident in the surface observations above, which shows calm air or very light down-slope flow at low levels, it could be occurring aloft.   Note the slight tilt of the smoke plume toward the Wasatch in the close-up photo.  This might explain the thicker haze in that portion of the haze pool, although that might also be related to emissions from whatever is generating that smoke plume.

As Close to "Normal" as It Gets

One of my pet peeves it the use of the word "normal" to describe climate averages.  Even The Weather Channel has raised concerns about this, yet it is commonly done by the National Weather Service and television broadcasters to describe the weather statistics on any given day.

It is perfectly "normal" in the midlatitudes for the weather to fluctuate.  The average weather for any given day does not equal normal.

Over the past 31 days, we have had a very good example of this.  In fact, during the past 31 days we have had about as close to "normal" weather as we can have in late sumer and early fall.  The temperatures at the Salt Lake City International Airport have fluctuated up and down with a gradual cooling trend as we moved through September and early October.  There have been days with above average temperatures, and days with below average temperatures, but the fluctuations have not been extreme (only one record was tied during this period).

Source: NWS

In the end, after all these ups and downs, the average temperature for the 31 day period is within 1ºF of the 30-year average.  You don't get much closer to average than that.  The airport also received 1.02 inches of precipitation, which is just a shade below the 30-year average for the period.  

So, this has been a remarkably average fall, with relatively "normal" weather.  The end result is that the Wasatch Mountains seem to look as they should for mid October.  There is a skiff of snow in the high country (see above) and the leaves are past peak at upper elevations and near peak at mid elevations.

This aspen grove (~7800 ft) is still a bit green and just approaching peak 

Near 8500 ft we're probably near or just past peak

This view up Butler Fork shows that the highlands between Big Cottonwood and Mill Creek Canyons are
now past peak, but leaves hang on in some areas.

There are some exceptions to this rule, which may be partly related to aspect and wind exposure.  One thing is for sure, this weekend is probably the last gasp of decent leaf peeping above 7000 feet.  By next weekend, most of the aspen leaves will be gone.

Finally, I have to comment that we are in the early stages of what is expected to be a very dramatic increase in global and regional temperatures.  While the past 31 days is within 1ºF of the average for the past 30 years, that probably puts it about 1.5ºF above average for the 20th century (I could run exact numbers, but hey, it's the weekend).  Thus, average for us is not average for our grandparents.  

No Niño Forecast Persists

Early last week, the Climate Prediction Center issued its monthly El Niño/Southern Oscillation (ENSO) diagnostic discussion, confirming earlier forecasts for "ENSO-neutral" conditions to continue through spring 2014.  ENSO-neutral means that neither El Niño nor La Niña conditions will predominate.

For the Wasatch Range, this means little.  We discussed last month how little correlation there is between snowfall at Alta and ENSO (see Outlook for the 2013–2014 Ski Season), as illustrated by the reproduced figure below.

Three month (NDJ, DJF, JFM, FMA) accumulated snowfall at Alta–Guard vs. the
corresponding ENSO index.  Courtesy Jeff Massey.

So, regardless of what you see in the news, or crazy ideas about caterpillar fur or groundhogs, nobody can say with any reliability what this year will be like in the Cottonwoods  We have roughly equal chances of a below average, average, or above average snow year.

Fall Break Outlook

Fall Break for the University of Utah students is almost here.  The annual pilgrimage to southern Utah and the Colorado Plateau begins for some today and continues the next few days.  There is an embarrassment of riches to choose from.  Perhaps you have a permit visit the wave or are just planning a trip to one of the National Parks.  Ah, what a great trip it could be, if our inept Congress could just get their act together and pass a budget or continuing resolution.  

Should that happen, or you are targeting other great destinations that remain open for "business" (e.g., the San Rafeal Swell), here's a quick-and-dirty outlook.  The main fly in the ointment is a trough that pushes into southern and central Utah late Sunday and affects the weather through Monday.  Right now, precipitation extends down to about Cedar City and Moab, but keep an eye on the forecast in case this changes.  Be prepared for changeable conditions for Sunday to Monday.

Source: NWS

Beyond that, the outlook suggests ridging with mainly dry weather - very nice for Fall Break.  Let's hope this long-range forecast holds.

Source: NWS

The Digging Trough

The loop below shows the IR satellite imagery and 500-mb height analysis for the 2-day period ending this morning.  It shows an outstanding example of what meteorologists refer to as a digging trough.  

A 500-mb height analysis is essentially a topographic map, except instead of showing the elevation of the terrain, it shows you the elevation of the 500-mb pressure level.  Troughs are areas where the 500-mb level is locally low, and ridges are areas where the 500-mb level is locally high.  The flow roughly parallels the height contours with lower heights on the left and is stronger in areas where the height contours are close together.  Thus, a meteorologist can look at a map like the one above and quickly ascertain the large-scale flow and how it has been evolving (or, see how it will evolve in the future using a model 500-mb height forecast).

A digging trough moves very strongly southward and often amplifies, forming a closed low center.  One can see this in the loop above.  Note how a subtle short-wave trough along the SE Alaska/SW British Columbia Coast amplifies, forms a closed low, and then "digs" very dramatically southward into northern California.

Typically digging troughs are characterized by a short-wave trough and associated jet streak, an isolated  area of  strong jet-level flow, moving down the back side of a long-wave trough, as is the case above.  Often there is a cyclone forming and acting to build the ridge immediately upstream, as also can be seen above over Alaska.

The ability to forecast events like this is a product of advances in satellite meteorology and computer modeling.  We take it for granted today, but reliable forecasts of events like this simply weren't possible until we advanced the diversity and density of satellite observations collected over oceanic regions and developed computer models that could effectively use those observations and produce reliable forecasts of dynamic "nonlinear" weather systems like digging troughs.

A Lifetime of Skis

Yours truly blows off a day of graduate school for turns at Crystal Mountain, Washington.
Skis: K2 KVCs.  Boots: Salomon SX-91 (yeah, rear entry).  Poles: Kerma "corrective angle."
Yes, that is a flourescent pink turtleneck.  Jealous?  April 1991.

As I was going through some old photos the other day I thought of two things.  First, I'm really glad I didn't grow up in the digital photography era.  Some things are best left to hazy memories or personal photo albums.  Pity you youngsters out there.  Second, I can remember every pair of skis that I've owned, although a couple of the model names remain a bit unclear.  Below is my lifetime in skis.  Feel free to comment and share some of your most memorable boards.

Trek XC skis (circa 1979): My first "boards" were skinny skis as my parents took up cross-country skiing when I was in my early teens.  I can't remember the model, but they were grey, nowax, and very slow.  At least that was my excuse as I tried to keep up with my friends.  

"Fiberglass" skis with cubco bindings (circa 1981):  It's a damn shame I can't remember the make and model of these skis, but in my mid teens I skied a few days on the local hill with a pair of "fiberglass" skis (you know they were old if that's what they were called) with cubco bindings I got from a friend.  The boots barely came up above the ankles.  Yeah, they were an antiquated death trap, even in 1981, but after a few years on skinny skis, they were a dream.  Plus, if you use your imagination, the cubcos look a bit like a Dynafit tech binding, but weighing ten times as much.  

Source: retro-skiing.com

K2 skis (circa 1983): At some point I sprung for a pair of new skis with modern bindings (ah, DIN standard) and boots (yup, rear entry).  I can't remember the model, but it's irrelevant. These were intermediate skis, stacked deep and sold cheap.  At the time (and this is probably the case today), K2 would crank out a bazillion of these skis and slap different top skins and model names on them so that shops carried their own model.  They were real noodles, but at the time I couldn't carve a decent turn if my life depended on it.    

K2 Slalom 66 (3 pair, circa 1985-1988):  By the end of high school, I figured I needed a better ski, but was worried that a full-bore slalom ski might be too much for my rudimentary style, so I opted for K2's "soft" slalom ski.  K2 has made a number of great slalom skis.  This wasn't one of them.  Plus I broke 3 pair in 3 years.  Fortunately they had a good return policy.

K2 712 (circa 1986):  These were actually older than the K2 Slalom 66s, but I picked them up used to have a decent pair of rock skis.  That they were and the served me well for many years.  Even on good days, I often skied them rather than the Slalom 66s.

K2 Unlimited VO (circa 19879): Old schoolers out there will remember that there was no such thing as a one-quiver ski in the late 1980s.  K2 tried to change that with the Unlimited VO, a ski that I absolutely loved.  You can still pick up a pair here.

K2 KVC (pictured in top photo, circa 1988):  Being an eastern skier, the Unlimited VO was all fine and dandy, but I needed something for bulletproof ice.  Hence I sprung for the stylishly pink accented K2 KVC.  I also have great memories of these boards as it was during this period that I began to get my ski legs and become a stronger technical skier.  

K2 UVO (circa 1989): I really can't remember precisely when I got these, but they were the followup to the Unlimited VO and thus an obvious replacement.  They did ski well, but they had the worst name and some crappy pastel graphics.  They were my "powder" ski (or more aptly put crud ski) when I first moved to Seattle.  Eventually I put a pair of Silveretta 404 bindings on them and they became my first backcountry setup.

K2 5500 (circa 1991): I won these in a raffle.  When I worked in a ski shop during college, my boss once told me they were a good ski for middle age men.  Perhaps this biased me as I hated them.  I tried them twice, found them squirrelly, and dumped them like a bad habit.

Salomon 2S (circa 1992): Salomon began making skis in the early 90s and I switched to their 2S, a so-called "round turn slalom ski" (at the time, slalom racing had digressed into an ugly "J-turn style that I thought was an abomination).  I eventually moved the Silveretta 404s to them and, in addition to Cascadian tours, I actually skied these a few times in the Wasatch backcountry, but don't tell anyone.

Rossignol 4G (circa 1993): I picked these up used from a friend for the express purpose of skiing très grande vitesse.  The purple top skin matched my one piece too :-).

Salomon 2S (circa 1994): I opted in for another pair.  I had these for a very very long time as I began to tour more and ski resorts less and was too cheap to pony up for new boards for the few days a year I was running laps.

Salomon SuperMountain (circa 1999): After years of badmouthing "fat" skis, I finally bought a pair. Yeah, "fat" at the time was a 78 mm waist, but after years on narrow, stiff slalom boards, I felt invincible on these skis.

K2 Piste Stinx (late 1990s): Sanity prevailed in the mid-to-late 90s when I bought these skis, put tele bindings on them and became a backcountry paramarker, dumping the heavy metal Silveretta 404s.  And not a moment too soon.

Rossignol (unknown model, late 1990s): I picked up a used pair of rossis with tele bindings at a swap when I was suffering from some sort of telemark affliction.  I never liked 'em, but fortunately they were cheap.  I think they ended up in the garbage can.  I couldn't even give 'em away.

K2 World Piste (early 2000s): Another tele setup for paramarking.  This one with an 80 mm waist!  I covered a lot of miles on these boards.

Dynastar Legend 8000s (circa 2005): I wasn't skiing much at the resorts during the early 2000s, but got these as my son advanced and I wanted something with which to carve the groomers with him.  This was a really smooth carver and the first pair of boards I owned at sub 180 cm.  My back loved them!

Karhu Jak BC (circa 2006):  Of all the skis I've owned, I think this one was the most underappreciated by fellow skiers.  I'm not sure why it didn't take off as the board of choice for Wasatch tours.  It was midfat, lightweight (7.3 lbs), and skied like a dream in just about anything but upside down powder.  Drew Hardesty of the Utah Avalanche Center liked them so much that last year he told me to give him a call if I ever want to get rid of them.

Rossignol Phantom SC97 (circa 2009): As my son began to explore the mountain in all conditions, I decided to go a wee bit wider, opting for the 97 mm wide Rossi Phantom.  I have a ton of good memories of these skis primarily because of all the powder skiing I did on them with my son.  This is still my main alpine ski, although admittedly an upgrade is needed.

Dynafit Manaslu (2012): I've never been into big wide backcountry boards.  The Manaslu is a good modern option for old-school skiers given its "modest" width (95 mm waist) and sub 7 lb weight.  I like these boards, but back problems have thusfar limited my mileage on them.

Top 5 Best Memories (chronological order): K2 Unlimited VO, K2 KVC, Salomon SuperMountain, K2 World Piste, Karhu Jak BC