Wasatch Weather Weenies

Does this Memorial Day pow put Alta over 800" for the winter? Photo: T. Cruickshank Has Alta hit the coveted 800" mark for the winter?  Call it psuedoscience if you will, but with a little creativity, here's what I come up with for the year. The snowfall history on the Alta web page  reports a cumulative season snow total of 723.5" since 1 October and 681.5" since 1 November.  I believe this is based on twice-daily snowfall observations from the Collins observing site, which is located just above mid-mountain at 9662 feet elevation in Collins Gulch. Such observations have not, however, been collected at Alta-Collins since 1 May.  Thus, we need to be creative to get the total through May. Fortunately, snowfall observations are also collected at Alta by the Utah Department of Transportation (UDOT) at the so-called guard station across from the base of the ski area at 8700 feet elevation.  From 1 Nov - 30 Apr, they recorded 553" of snow, 128.5" ...

Source: West and Steenburgh (2011) After a long and arduous rewrite, my paper with Greg West on the Influence of the Sierra Nevada on Intermountain cold-front evolution has finally been accepted by Monthly Weather Review .  If you are an aficionado of Intermountain weather, this is a must read as it will probably cause you to think differently about how the Sierra influence cold fronts as they move across the Intermountain West. The paper may be downloaded by clicking here .  Comments appreciated of course.

We discussed the possibility of a cold snowy Memorial Day back on Friday , but I still feel like I'm in a time warp or Twilight Zone episode.  I woke up this morning and there was snow on the ground at my house in the Avenues.  Then, I went out and picked up the paper and they had delivered a Deseret News instead of a Salt Lake Tribune.  Weird... In the Collins lot, there were so many cars I had to check to see that the lifts weren't running.   Alta, 30 May 2011.  10" of new snow.  192" snow depth. Skinning up Collins Gulch, the cover was about as good as you'll ever see it. Nearing the ridge, fighting the wind, it certainly felt more like February than May. Yours truly sucking wind.  Photo: Tyler Cruickshank And then the turns.  A bit inconsistent and stiff in places, but pretty much as good as you can get on Memorial Day.   Tyler Cruickshank samples the smoke at my Memorial Day BBQ.  May 30?  Yeah, right.   ...

As discussed on Friday , the doom and gloom has returned to the Wasatch Front for the latter two days of the Memorial Day weekend. Snowbird reported 4" of new snow this morning, while the depth at the Alta-Collins snowstake has increased from 179" to 184". More snow is expected in the Wasatch through Memorial Day.  In particular, the NAM model is going for about .6" of snow water equivalent at Alta-Collins from early tmomorrow morning through tomorrow afternoon, with a forecast snow-density of about 10%. It won't be the Greatest Snow on Earth, but tomorrow will provide an opportunity for Memorial Day freshies...and perhaps even good skiing at the upper elevations.  Bring your googles because if the NAM model verifies, there will be storm skiing in the morning. NAM Model forecast valid 9 AM 30 May 2011. Snowbird's seasonal total is now up to 765".  By this time tomorrow, I expect they will be over 775".

Today we hit Snowbird and although we didn't ski the Greatest Snow on Earth, the turns were really outstanding for Memorial Day weekend.  Early in the morning we enjoyed some creamy skiing in Mineral Basin, with the snow nicely softened by the morning sun. The cover is absolutely amazing.  This is the year to ski lines like the pipeline that's for sure.  I snapped the photo below on the Peruvian chair only because if you didn't look at the calendar, you'd swear it was early March instead of late May. We've discussed the problems measuring snow on several occasions, most recently with regards to the Alta snowfall record .  There's a nice article discussing these problems and recent efforts to address them in an article in the latest UCAR quarterly entitled How Deep the Snow?   Enjoy!

Endless winter continues in the Intermountain West this weekend. The "warmest" weather comes today (Friday) and tomorrow (Saturday) in advance of an approaching upper-level trough from the west.  With a strong baroclinic zone draped across the state today and tomorrow, temperatures will be much higher in southern Utah than northern Utah. NAM Model forecast valid noon Saturday 28 May 2011. By Sunday, however, the trough has amplified and moved into Nevada, with a band of precipitation forecast to be sitting over northern Utah.  Further, 700-mb temperatures along the Wasatch Front have cooled to about -4 C.  Thus, we'll see snow levels dropping to about 8000 feet.  Southeast Utah remains, however, ahead of the developing front and remains in the warm air, albeit with strong winds and potentially blowing dust. NAM Model forecast valid noon Sunday 29 May 2011. By Monday there's no escape as cool air has spread across the whole state.  With cool, moist we...

One of my graduate students, Trevor Alcott, noticed this morning that there was a remarkable  seiche on the Great Salt Lake thanks to the overnight  cold-frontal passage . A seiche is a temporary rise (or fall) in lake level that can be caused by strong winds, earthquakes, and other phenomenon. At the Saline USGS lake-level observing site, which is located on Promontory Point and in the north arm of the lake, the lake-level averaged about 4196.2 feet from 19–24 May.  On the 25th, however, the lake-level decreased gradually, followed by a rapid spike to 4197.7 feet early in the morning on the 26th (today).   Source: USGS.  Times appear to be MST or MDT. Why did this happen?  Note the persistent easterly flow during the day at Gunnison Island, which veered slightly to SE with the approach of the front at roughly midnight MDT.  During this period, the lake-level at Saline decreased as the wind transported water to the western side of the Great Sal...

By nighttime standards, we had a pretty good frontal passage (fropa) last night.  At KSLC, note the abrupt drop in temperature and increase in wind speed (with a gust to 49 mph) at about 0930 UTC (3:30 am MST). The radar at this time showed an abrupt transition in radar reflectivity with considerable "clear air return" in the post-frontal environment. It looks to be a bit dusty around the Salt Lake Valley this morning.  Thus, it appears the strong post-frontal winds picked up some dust from Nevada and/or the West Desert and transported it into our area.

Correct me if I'm wrong, but I can't think of a good U2 song that is weather related.  Bullet the Blue Sky uses weather in a metaphorical sense, but that is such a strong protest song that it doesn't seem appropriate to use it for weather.  Thus, the video above is simply of one of the great live songs from an era when my generation realized we were witnessing what would become the biggest band in the world . I just took a look at the latest (0600 UTC) model runs and I'm optimistic that the weather will improve for the show this evening.  The NAM and GFS are bringing in drier air and are stabilizing things aloft.  The NAM model sounding for 8 PM MST, just before U2 takes the stage (scheduled for 8:45) looks pretty good with a healthy stable layer down to about 650 mb. Keep your fingers crossed the models are on track and it will be dry for the concert.  One aspect of the forecast is easy.  You can count on U2 to put on a great show.  Enjoy!

Given the interest in tornadoes because of the large number of fatalities this year, I'd like to point everyone to an excellent FAQ prepared by Roger Edwards of the NOAA Storm Prediction Center . Roger Edwards' Tornado FAQ .  Everything you want to know about tornadoes, but were afraid to ask.

Another tragic tornado has rumbled through the midwest.  Below are radar reflectivity and velocity images from yesterday afternoon's event in Joplin, MO. Seen at center left is the remarkable signature of a mesocyclone.  In particular, note the incredible hook-like appearance in the Doppler velocity analysis.  One of our readers wanted a cross section, but I'm operating in mobile fashion and don't have all my tools at my fingertips. Unlike most meteorologists, I have no interest in seeing another tornado after watching the 1999 Salt Lake event rumble through my neighborhood.  I prefer storm chasing Utah style, which involves deep powder skiing in the Wasatch Range.

May 21, 2011 is here and the end of the world is coming , at 6 PM to be precise, according to California preacher Harold Camping.  I suspect the day will go by without incident, other than some complaints about the flexible hours at Snowbird today.  According to their mountain report: "[Snowbird] will open at 8am today. There will be limited terrain accessed by Peruvian Express, Mineral Basin and Little Cloud. The skiing and riding is recommended for experts only. It is possible the mountain will close at noon, if conditions permit we will remain open until between 1:30pm-2:00pm. Lift tickets today will be $50." Preacher Camping and other end-of-the-world types like to pick a day that the world will end,  but that "day" won't come until a few billion years in the future when the sun exhausts it's nuclear fuel and expands into a red giant.  Oh what a party that will be! Micheal Stipe of REM, however, sings about something altogether different, the end of...

Have You Ever Seen the Rain by Credence Clearwater Revival is one of the great weather songs of all time (although in the song, rain is probably used metaphorically ) and it just seems perfect for today. One of our readers brought up the possibility that some of the moisture from this ongoing storm originates with the Gulf of Mexico.  I may take a closer look at this today, but I did want to point out the tremendous plume of high precipitable water that wraps around the cyclone from the Gulf of Mexico, into the High Plains, across Montana and Idaho, and then into northern Utah.  Incredible! 1200 UTC IR satellite and radar imagery with GFS precipitable water and 700-mb wind vectors Typically tracing moisture in storms is more complicated than you think, in part because the sources can vary considerably depending on what altitude you are looking at.  Nevertheless, at least for the late stages of this storm, it does appear the Gulf of Mexico is playing a role. ...

This has been and continues to be a fascinating storm for northern Utah.  I'm about as close to developing seasonal affective disorder as I've been since I left Seattle 16 years ago. At KSLC, it seems like it has been raining continuously since 1400 UTC (0800 am) yesterday morning, although there were some breaks overnight from 0150-0426 UTC and 0519-0805 UTC.   An interesting aspect of this event is that it has rained  everywhere .  As of 7 am this morning: .87" in Logan 1.7", 1.59", 1.3" in Centerville, Bountiful, and Ogden, respectively 2.21", 1.6", 1.35", 1.0", and .82" in Cottonwood Heights, Taylorsville, Sandy, KSLC airport, and the Great Salt Lake Marina, respectively .32-2.36" in the West Desert, including 1.51" at Aragonite 1.21", .91" and .73" on the Wasatch Back at Weber River near Morgan, PC Golf Course, and Kimball Junction, respectively 2.8" and 2.3" at the Harbscrabble and Farm...

Source: NWS Note from Jim: Post updated 2:25 PM 19 May with correct information from Utah Weather and Climate.  It's a pretty simple question really , "What is the Alta Snowfall Record?"  Good luck, however, finding a consistent answer. According to the Western Region Climate Center , Utah's maximum winter snowfall is 846.8", set at Alta in 1982-83. According to Utah Weather and Climate by Pope and Brough, the Alta " year " (Sep 1983–Jun 1984) snowfall record is 808.5" set in 1983–84 and the seasonal snowfall record is 743.5" set Nov 1983–Apr 1984 What gives? There are several issues here.  First, what is the time period of the observations and what is meant by winter, year, or season. There does not appear to be a definition of winter on the Western Region Climate Center, but I suspect they are actually referring to the water year, which is from Oct-Sep. I don't know what the definition of season is.  Based on the Alta  ...

A remarkable 24" storm total has been reported as of 7 am this morning in upper Big and Little Cottonwood Canyons. As an example of the challenges of measuring snow and snow density, the snow water equivalent in Big Cottonwood was 2.62", whereas it was 1.97" in Little Cottonwood, despite the fact that the site in Big Cottonwood is at a higher altitude. Measurement challenges aside, this is a big May dump.  I especially like that Snowbird has given up on digging out their snowcam, although I miss being able to use it to assess snow rates. Source: Snowbird.

There have been many comparisons made lately between the spring of 1983, when flooding famously led to City Creek Canyon, and 2011.   The floods of 1983 when City Creek was diverted down State Street.  Source: Wikipedia Commons/US Government. The two years are similar in that both featured an abundant mountain snowpack and a cool, wet spring that extended the snow accumulation season well into May.  This can be seen, for example, in the SNOTEL data for Ben Lomond Peak.  On average, snowpack snow water equivalent (SWE) at Ben Lomond Peak reaches a maximum of ~43" in early-mid April, whereas this year's peak of ~60" was reached just after May 1.  In 1983, we reached ~67" about May 20th!  What a year that was.   This year we've actually had a few snowmelt periods during late April and May, whereas in 1983 it just stayed cold and snowy right until the bitter end.   Although both springs were cool and wet, the large-scale circulations in the two...

It has certainly been a cold spring in Utah, but how cold?  Has Hell frozen over?  Is this the end of global warming? According to the National Climatic Data Center, Utah's average temperature in April was below average, but only the 35th coolest of the past 117 Aprils.  If you want really cold, in relative terms, head further north to the Pacific Northwest where Washington observed its 2nd coldest April of the instrumented period. Source: NCDC The statewide average, however, is a bit deceptive for those of us who live in northern Utah where the departure from average was the largest in the state.  In contrast, southern Utah's departure from average was smaller or even slightly positive in a few spots. Source: NCDC At KSLC, the mean temperature for April was 45.4 F, 4.6F below the average for 1971-2000.  Not exactly BBQ weather, but it did make for good skiing. As can be seen in the above analysis, we were a country divided in April with much below a...

This is old news, but one of my students pointed out to me today that there was a mind-boggling contrast in airmass between Salt Lake (purple) and Elko (red/green) yesterday afternoon. That's pretty much as large as they come around here with a surface temperature contrast of a whopping 27C and a 700-mb contrast of ~18C.  

Our numerical forecast models are the backbone of modern weather forecasting, but sometimes you can just look at an analysis an know what's coming. That was the case this morning when I pulled up this satellite image and 500-mb height and absolute vorticity analysis. In particular, there is not only a long-wave upper-level trough over the western United States, but another one upstream over the Gulf of Alaska.  This upstream trough is also strongly diffluent, meaning that there is strong diffluence or spreading of the flow on the downstream side of the trough.  Further, the trough is negatively tilted, which means that the trough axis isn't oriented meridionally (i.e., along a meridian) but instead along a SE-NW axis. In such a configuration, the strongest cyclonic vorticity advection lies in or near the base of the trough axis, which results in the trough digging (i.e., plunging southward) as it moves eastward.  In the configuration above, that means this trough w...

We've gone from a morning canyon wind event to an afternoon with screaming southerly winds.  I always wanted to call these strong southerlies the "Intermountain Scirocco" as they bear many similarities to the Scirocco winds of North Africa, but Mark Eubank once told me he called them the Hatu winds for Utah spelled backwards.  Hatu it is... First, let's have a look at some of the winds out there.  At 0018 UTC 16 May, several stations in the west desert and over the Great Salt Lake are reporting gusts in excess of 50 mph. 0018 UTC 16 May MesoWest surface plot. Wind gusts in mph annotated. Grassey Knolls along I-80 just west of the Cedar Mountains had a peak gust earlier today of 66 miles per hour.  Not exactly fun for high profile vehicles. The nearby UDOT traffic camera shows dusty conditions too. Where is this dust coming from?  Well, a lot of it appears to be coming from three point sources in southern Utah, as evident in this enhanced MODIS imag...