Wasatch Weather Weenies

An impressive surge of monsoon moisture is currently occurring over Utah.  Below is a loop of High Resolution Rapid Refresh (HRRR) model analyses and forecasts of precipitable water for the period from 0400 UTC 31 July (2200 MDT yesterday) through 0200 UTC 1 August (2000 MDT this evening).   Precipitable water is the depth of water you would have on the ground if you were to condense out all the water vapor in an atmospheric column.  Thus, it is a measure of the total integrated water vapor in the atmosphere.  Note how high values move northward from Arizona and the lower Colorado River Basin into Utah.  Values in Salt Lake City increase from about 12 mm (0.5 inches) to about 30 mm (1.2 inches).  Surface dewpoints overnight increased steadily with the surge, as illustrated by meteograms for St. George and Salt Lake City.  The latest (1505 UTC/0900 MDT) satellite and radar analysis shows extensive upper-level cloud cover over Utah....

Last week, we discussed how we were in a pattern characterized by persistent upper-level ridging over the western United States, but that "critters in the woods" would modulate the monsoon moisture and shower and thunderstorm activity (see Persistent Large-Scale Pattern with Critters in the Woods ).  One of those critters gave us the relatively pleasant weather on Saturday and another will be affecting northern Utah on Wednesday.  The setup for Wednesday illustrates how both large-scale and small-scale features play an important role during the monsoon.  The situation at 0600 UTC 30 July (0000 MDT Monday) shows a high-amplitude upper-level (500-mb) ridge centered near the 4-corners area.  Anticyclonic (clockwise) flow around this larg-e scale feature results in westerly flow to our north and easterly flow over northern Mexico as depicted below.  However, there is also an important smaller-scale circulation feature over northern Mexico.  I have iden...

I've been in Salt Lake City for nearly 25 years and in that time I've never been to the top of the American Fork Twin Peaks.  That changed today as my son and I bagged it via Gad Valley from the base of Snowbird.  It's a really great hike, with some ridge scrambling that is fun and offers some great views.  The photos above were taken in fairly meadowy areas.  In others, there's some rock hoping and scrambling to be had, but not difficult.  Perhaps class 3 in a few places.  In places there's a faint trail, but not much.   Views from the Red Stack were really spectacular.  Ditto for the views from the American Fork Twin. Timpanogos still has plenty of snow up high and the USFS was recommending ice axes/traction devices for ascending the Timp "Glacier".   I didn't feel bad about leaving my skis at home, however, when looking down Pipeline. I don't know where the Snowbird expansion plans are t...

I'm a big fan of the Tour de France, despite cycling's spotty history with performance enhancing drugs. In recent years, Team Sky (now Team Ineos) has dominated the race, making for generally boring racing, but this year, the race has been wide open, with as many as six riders having a legitimate shot at the yellow jersey entering the final three stages.  Further, the leader entering stage 19 (of 21), Julian Alaphilipe, was not a pre-tour favorite, adding to the intrigue.  Major surprises in long stage races are few and far between. I was hopeful that today's stage would remain dry after consulting MeteoFrance's Arome model yesterday, but it wasn't to be.  Thunderstorms laid down a major coating of hail on the end of today's stage, necessitating a halt of action while the riders were descending from the penultimate climb.  Conditions along the route to come were indeed unsafe.  Comically, overhead shots showed what looked to be a snowplow in action. Sad...

It was a pretty good snow year in the eastern Alps, but due to global warming, it's damn hard to have a year in which there isn't a net loss of glacier mass. When we left Innsbruck at the end of June, the seasonal snow still covered much of the high eastern Alps, but that's changed in the past three weeks.  Seasonal snow on the Hintereisferner, Austria's best studied glacier, is disappearing rapidly, leaving grey glacier ice.  Hintertuxer Glacier is Austria's only year-round ski area.  Here too, the deep seasonal snow cover is disappearing rapidly.  Finally, there is the Schneeferner on Zugspitze, which is to the right of the building pictured below. It's beginning to suffer too. I suspect at the end of summer, we'll see a net loss of mass for most of the glaciers in the eastern Alps.  Even in a good snow year, the summertime temperatures that exist today do their damage.  Additionally, the prolonged exposure of grey glacier ice results in ...

I'm not sure how blogger will handle it, but the loop below has been purposefully designed to run at high speed and to repeat to illustrate three key points about the GFS forecast for the next ten days.  First, the large-scale pattern changes little with persistent upper-level ridging over the southwest U.S. and the westerly mid-latitude jet to our north.  There are variations in the strength of the ridge and the center of its circulation, but these are relatively modest. Second, one can see precipitation "pulsing" in the lower right-hand panel, which depicts the surface forecast and includes the 3-hour accumulated precipitation.  This pulsing reflects the influence of the sun, with precipitation increasing and becoming most common later in the day and in the early evening and becoming less common over night.  Third, as can be seen in the top two images which depict the upper-level pattern, there are some "critters in the woods" in terms of upper-level...

During periods of weak large-scale forcing in the summer, the mountains play an important role in the initiation of convective clouds and thunderstorms.  Nowhere is this more apparent in our region than over the Uinta Mountains where a visit sometimes makes one feel like they've traveled to another planet. The photo below was taken from the Gobblers Knob summit at about 10 AM this morning looking east toward the Uintas.  As is often the case, one can see the first cumulus clouds of the day forming over the Uintas.  Often, these clouds grow in depth, producing showers or thunderstorms later in the day.  I don't know of a study that has specifically examined the influence of the Uintas on convective cloud initiation and evolution, as well as growth into thunderstorms, but I'll speculate here on one of the reasons why the Uintas are so active: their scale.  They are quite high and broad with large expanses of lower elevation terrain to the north and south of...

Data released Monday by NASA shows that June was the warmest on record globally ( see this Washington Post article ). The time series of Junes during the instrumented record (i.e., back to 1880) is shown below.  One can see the long-term warming trend, as well as the year-to-year variability caused by many factors including the El Niño/Southern Oscillation (ENSO), volcanic eruptions, and other climate-system variations. I've also added some news items and personal notes to provide some context as to what has been going on over the past five decades. In 1967, I was born.  Just two years later, and 50 years ago on July 20, 1969, humans walked on the moon in what was a truly audacious human accomplishment.  Although I have no memory of the Apollo program, NASA's space program had a real impact on my interest in science.  I remember, for example, requesting and receiving photographs of the Space Shuttle as a teenager. In 1975, Wally Broecker published a paper i...

According to the American Meteorological Society , the largest employer of meteorologists in the United States has traditionally been the government.  This includes the National Weather Service, military, as well as other agencies such as the Department of Energy. However, the private sector is growing rapidly.  Last week I attended a workshop sponsored by the National Science Foundation, American Meteorological Society, National Center for Atmospheric Research, Commodity Weather Group, BMS Re US, Millersville University, and Maxar to lay the groundwork for better preparing students for private sector employment.  Attending such workshops is absolutely critical for university faculty, especially those like me that have spent a great deal of time in the ivory tower.  Although I do some consulting and interact with private-sector companies, the reality is that I've spent most of my career in academia and, as one attendee put it, " t he private sector is not an al...

It was wonderful to return to the Wasatch last weekend and find so much water and snow.  It's been several years since it looked like this in early July (since 2011) and it helped us ease back into the climate of Utah from the wetter Austrian Alps.  Even the Mt. Superior butterfly said hello.  I missed a fairly remarkable late spring.  The climate summary for Salt Lake City International Airport shows a relatively cool stretch from mid May with considerable rainfall, followed by frequent intrusions of cooler air through early July.  Such intrusions make for much more tolerable weather.  Source: NWS That changes this week.  We've had a weak trough move through overnight, providing us with somewhat refreshing air and highs in the 80s today and tomorrow.  After that, the GFS is advertising a very typical July pattern with strong ridging centered roughly on the four corners.   I'm no fan of 10-day icon based forecasts, ...

The large-scale weather pattern over the Northern Hemisphere over the past 10 days (maybe longer but I haven't looked) has featured a high-amplitude flow pattern that one might describe as "wavy."  The slowly evolving nature of this pattern has resulted in persistent ridging over Alaska and the Gulf of Alaska and troughing over the western continental United States and adjoining eastern Pacific.  The situation in northern Utah on the 4th of July was further influenced by a short-wave trough (dashed line below in the analysis for 0000 UTC 5 July/1800 MST 4 July).  This led to the development of afternoon showers and thunderstorms that led, in my view, to an incredibly pleasant 4th of July, although admittedly some picnics and outside plans were doused.  Given my disdain for summer heat, that's a tradeoff I'm happy to make.  Looking at the numbers, yesterday's high of 83 and daily mean temperature of 71.5 were the lowest on the 4th of July since 2010 w...

Our nearly six-month residency in the Tyrol came to an end last weekend as we left Innsbruck, spent a night in Munich, and returned home to Salt Lake City.  Our entire time there was like a dream, exceeding expectations in every way. Having given my last lecture on Tuesday and finished grading on Wednesday, our last two days in Innsbruck involved packing and spending some time enjoying and reminiscing about the scenery and the city. On Saturday, we departed for Munich.  Six months previously, we unloaded our gear on a cold winter's day and sat on the sidewalk pictured below hoping our landlady would actually show up and give us a place to stay that night (she did and was a wonderful host).  Once again, we were on the street and hoping all would go well, which it did (and this time, Delta didn't lose any bags).  As we did for the trip out here, we packed carefully right to the limit of what Delta would allow with checked bags and carryons. We spen...