Wasatch Weather Weenies

Over the weekend, I noticed that my lawn and gardens were looking thirsty.  Awfully thirsty. April is climatologically the wettest month of the year in Salt Lake City.  The long-term average monthly precipitation since 1928 is 2.10".  Through yesterday, the airport reported only 1.19" for the month.   However, nearly all of that precipitation fell through April 18.  Since then we had only a trace until it started to rain last night.  In addition, it' has been windy and warm.  Saturday in particular featured a record high of 87˚F with dry southerly winds.   Thankfully, a slow moving cold front delivered desperately needed valley rain last night.  If you look carefully at the radar imagery this morning, you can see the flow shifting from SW to NW across the trough and how the trough is slow moving across northern Utah.  More importantly, there's plenty of valley rain.   Precipitation totals through ab...

There's little point in calling it spring skiing.  Temperatures are at record levels and running near averages for June 21st.  Nevertheless, Alta looked beautiful and the turns through noon were actually quite good.  The snow is going fast, however, on all aspects, with the south-facing side of the highway looking pretty bare for April 28th.  The Snowbird SNOTEL lost 4.4 inches of snowpack water equivalent in the past week, which is about 15% of the snowpack at that location.  I'm sure south aspects did worse.  More seasonable temperature return tomorrow, thankfully.  It is remarkably dry down here in the valley thanks to warmth and wind.  My grass is getting crispy and brown already. 

Guest Blogger: Larry Dunn  Ever since I started skiing when I was 14 years old, I became a connoisseur of road-side snow banks.  When traveling to a ski area, it was always a good sign when the snow banks were growing higher and higher as you got closer to the resort.   Good snowbanks in the Cottonwood Canyons are those that are about as high as your car when driving up the road, and its always a good sign when the snowpack seems to just spread out away from the road at nearly the same height as the top of the snowbank.  So, some years ago when I first saw pictures of what seemed to be truly amazingly high snowbanks towering over the tops of tour buses in Japan, it got my attention. Last week while in Japan I got a chance to go indulge my passion for snowbanks while traveling on the Tateyama–Kurobe Alpine Route.  The Alpine Route is basically a one-day transect of the northern Japanese Alps via bus, multiple cable cars, a tram, and two tunnels. ...

We're now deep in April and near the time of maximum upper-elevation snowpack in the interior western United States.  The contrast in snowpack characteristics from north to south through our region could not be more striking.  If we look at SNOTEL stations at elevations at or above 8000 feet, there are many in Nevada, Utah, and southwest Colorado that have already lost their snowcover.  In contrast, to the north, there are some in the Greater Yellowstone area with more than 100 inches.  The maximum is at the Fisher Creek Snotel, which is just north of Cooke City, Montana.  Snowpack water equivalent tells a pretty similar tale.  There's a total loss of snowcover at many sites in Nevada, Utah, and southwest Colorado.  The snowpack is phat to the north.   Sites above 50 inches of water are Fisher Creek noted previously and Grand Targhee in the Tetons.  Northern Colorado and south-central Wyoming have some decent numbers as well, includ...

Based on the forecasts I'm seeing right now, there's a pretty good chance we're at at the apex of the seasonal upper-elevation snowpack right now. The latest from the Snowbird SNOTEL shows a snowpack water equivalent of 30.1 inches (green line), which is 71% of median for the date and 70% of the peak median.  Those are close because the average time of peak median snowpack is about right now.  Forecasts for the next 10 days show loaded dice for warm, dry conditions.  You know, the stuff we can't seem to shake.  There's always hope that a weak system or two can generate something, or that the forecasts are simply wrong, but the 6-10 day outlook is pretty telling.  Thanks to the dust storm earlier this week, snirt is emerging pretty quickly and was visible in many areas this morning.  The photo below is of Lake Peak in upper White Pine.  The dust is co-mingled with the melt-freeze crust that developed prior to the Tax Day snowfall. ...

How (or why) did you become a meteorologist?  It's a question I ask my students on the first day of class each semester.  Many people who are meteorologists have wanted to be one for most of their lives.  Often they can point to a specific weather event, perhaps a tornado, hurricane, or winter storm, as the moment that they decided to go into meteorology.  In some cases, I know multiple people who were motivated to become a meteorologist by the same storm .  I was infected early by the weather bug.  My path to meteorology was paved by youthful experiences in the Adirondack Mountains.  The weather in the Adirondacks is usually somewhere between partly and mostly crappy,  and in the late 1970s and 1980s the forecasts were truly terrible.  Whether hiking, backpacking, canoeing, nordic skiing, or alpine skiing, we had to be prepared for anything.  There are, however, two backpack trips that were essential for sparking my interest in weat...

Interesting forecast situation through Friday night as a closed upper-level low, which rumbles like a bowling ball across the American southwest, moves along the Utah–Arizona border. If you look at the 3-h NAM precipitation forecasts above (color fill) you can see that northern Utah misses out on the action initially, but does get some after the low enters Colorado thanks to so-called  wrap-around precipitation.   In the NAM forecast above, that precipitation primarily affects northeast Utah, especially the Uinta Mountains.  The Wasatch are at the edge of the action and in fact Alta gets no precipitation from the forecast above (but it is right on the edge of it).  The strong contrast in precipitation probability from west to east across northern Utah is better illustrated by the probability of more than 0.10 inches of precipitation during the 12-hour period ending at 0600 UTC 21 April (0000 MDT Saturday) based on forecasts by the Short Range Ensemble For...

The tax man cometh and hath taken away your spring. Following a high of 75˚F yesterday, it makes perfect sense to wake up to a coating of snow this morning.  After all, this is spring in the Intermountain West. Most of that snow was produced by the passage of the frontal band overnight.  However, early this morning, lake effect got going and trained off into the Salt Lake Valley eventually shifting eastward into my neighborhood, namely the Avenues and University of Utah at around 1340 UTC/0740 MDT. Most of the precipitation falling from then through 0800 MDT was in the form of graupel, which is basically a small ice pellet formed as supercooled liquid water droplets freeze on contact with ice crystals.  The graupel was relatively warm and cohesive and clung together just enough for demonstrations of the viscoelastic nature of snow. The ski cognoscenti know that graupel is wonderful to ski on.  I would take a good, prolonged graupel storm over the ...

The Wasatch Front has long had episodes of poor air quality related to elevated PM2.5 concentrations during our dreaded wintertime inversions.  We have also seen episodes of elevated and sometimes unhealthy PM2.5 concentrations due to blowing dust.  There are multiple dust sources in southern and western Utah, but this winter, the Cedar Valley west of Utah Lake has been especially productive. One of our post-docs, Derik Malia, first brought this source region to my attention in December.  In my blog post on December 21, we discuss two major dust plume events that clearly originated from the Cedar Valley on 3 December and 19-20 December.  Below are MODIS imagers of those two events clearly showing the plume extending from the Cedar Valley to the Salt Lake Valley. Today?  Same story.  The latest MODIS shows the Cedar Valley is the primary source for the dust impacting the Salt Lake valley.  Look at the clear plume that begins just to the west o...

Strong cold fronts and associated mayhem are pretty common in northern Utah around Tax Day.  The all-time classic is the 15 April 2002 Tax Day Storm, which produced the 2nd lowest sea level pressure observed in Utah since record keeping began in 1892, temperature falls of 7˚C in 10 seconds and 19˚C in 2 hours, and wind gusts of more than 60 knots.  Others include the 2015 Tax Day Storm, described by Judy Fahys in this KUER article .  We would have another today, if not for an oddity in the calendar.  Chances are you've noticed the nuking southerly flow, and the NWS has wind advisories or warning's up for much of weatern and southern Utah. The view from my office is starting to look dusty.  What a shame it will be if we put down a layer of brown goo on the wonderful white snow we have right now.  The culprit in this case is a strong front and surface trough to our west.  These features are forecast by the HRRR to extend across far NW Utah at 20...

It's been a lousy ski season, but if you've given up on it, you are missing out on some great skiing. Mother Nature took pity on Wasatch skiers and delivered some great skiing.  Most of the Steenburgh group headed to the Wasatch backcountry on Friday for a Mountain Meteorology field day.  No bad luck on Friday the 13th for us.  Note the smiles. I woke up this morning with an itch to ski some groomers, which I haven't done in about two months.  Conditions at Alta were really fantastic.  The groomers were highly carveable and I even got some freshies in the Castle shortly after the rope drop.  A few clouds did nothing to spoil the day.  The sun can spoil the snow quickly in April, but before the snow softens, it's wonderful to ski with every aspect well lit, something that does not happen during the winter months. The forecast "closing day" and the Frank is looking warm and springlike, with some mid and upper-level clouds around and a breeze ...

It has been a long cool season characterized by frequent doldrums, but today my cup runneth over. Let's talk first about what happened overnight and some of the complexities of cyclone and frontal evolution over the Intermountain West. With an approaching trough from the west, one often sees a trough develop over the Intermountain West, typically along an axis running from the high Sierra northeastward across northern Utah.  That was the case last night, which featured a very well developed Intermountain Cyclone, as well as a Pacific cold front that was distinct from this feature and pushed across northern Nevada.  As can be seen in the HRRR-derived analysis below, the Intermountain cyclone progressed northeastward across northern Utah overnight, with the cold front penetrating into the state and eventually overtaking the concomitant trough.  This resulted in some strange time series in which the wind shifted to northwesterly before the arrival of the col...