Wasatch Weather Weenies

I've been taking a peek at the weather in Salt Lake and remembering why I prefer to go on vacation in July.  It looks miserably hot there. I'm back in the Adirondacks for a few days for a celebration of my Dad's life.  Yesterday we did a hike in his honor up Gothics, an iconic peak on the Great Range.  As is typical of Adirondack trails, the route was merciless and direct, involving ladders, rock scrambling, and "vegetable belays." Don't let people tell you that there aren't avalanches in New York.  They happen and they have resulted in fatalities .  The path below comes off the shoulder of Gothics.   Gothics' name comes from the various rock faces and slides that surround the summit, which resemble Gothic architecture.  Although I think the west side is more scenic, we approached the summit from the east. Nearing the summit. On the summit, we got a view of Mt. Marcy, the highest peak in New York, but, as seems to be t...

The summer from hell is here.  Other than a brief cold surge earlier in July, this summer has largely been characterized by sustained warmth.  We are in a dead heat with 2013 for hottest on record. Source: NOAA Regional Climate Centers Temperatures this afternoon at the Salt Lake City Airport reached 100 degrees for the 8th time this year, and here's the forecast for the rest of the work week. Looking for snow?  Good luck.  Here's the view above Big Cottonwood yesterday.  Sad.  

A major wildfire broke out on Antelope Island yesterday.  There were some great photos flying around on twitter of the orange glow and flame front overnight, such as these on the KUTV web site . I took advantage of the cool weather and went out on an early morning bike ride to survey the scene.  During the day, the scene is a bit less "volcanic", but smoke obscured a good portion of the southern half of the island.  Note how the smoke is being transported southward, which reflects the northwesterly flow in the wake of a weak cold front that passed last night. There's a sharp edge to the top of the smoke. This is because there is an inversion in place over northern Utah behind the cold front.  The morning sounding from the Salt Lake City airport shows the inversion extending from the surface, where it was about 20ºC to 800 mb, where it was about 23ºC. We will see smoke mixing through a deeper layer later today as intense surface heating mixes out the i...

This may sound like a broken record given that I've mentioned it several times this summer already, but there's more to heat waves than maximum temperatures.  Maximum temperatures get the most press, but minimum temperatures strongly affect human comfort, animal and plant health, energy demand, and even air quality. Bars in the graph below show the range of temperature (bottom = minimum, top = maximum) each day this month compared to average (green shading), record maximums (top of red shading), and record minimums (blue shading).  Over the past 3 days the maximum temperature has fallen short of records by a few degrees, but the extreme warmth of the period is evident in minimum temperatures that are remarkably high. Source: NWS The minimum temperatures the past three days were 81ºF, 77ºF, and 79ºF.  Plus, our overnight minimum last night was 79ºF.  The 81ºF is the highest minimum temperature ever observed in Salt Lake City, as summarized nicely by the graphi...

Although many people focus on maximum temperatures, minimum temperatures also affect heat wave severity, especially for human or animal comfort for those who do not have some sort of air cooling capabilities. With the wind stirring things up the past three nights, overnight temperatures have not dropped below 77ºF in three days at the Salt Lake City airport.  Overnight minimum temperatures those three days were 81ºF, 77ºF, and 77ºF.   Maximums those three days topped out at 99ºF, 98ºF, and 99ªF.  We are on pace for something around 91–101ºF today.  I hope we hit 100.  99 is such a waste of a temperature.  If we are to be saddled with Fahrenheit temperatures as a nation, go big or go home.

The dog days of summer are now here.  The latter half of July is the climatologically hottest period of the year in Salt Lake.  I call it nuclear summer.  High sun angle.  High temperatures.  High-based cumulus clouds that tempt us with rain (although there were a few spots that saw drops along the Wasatch Front yesterday evening).  Brutal. How about a few photos today to remind us that we are cresting the hill and will soon be on the "downhill slide" to ski season.

Often during the North American Monsoon, Utah is located in a region of large-scale confluence where airstreams of different origins are drawn together between the large-scale trough along the Pacific Coast and upper-level ridging over the south-central US.  This often leads to a strong contrast in moisture and thunderstorm activity from east to west across the state.  It's a bit of a stretch, but you could call it the Monsoon "Dryline." We have such a situation today with confluent flow over Utah leading to a strong contrast in precipitable water [a measure of the total water content of the atmosphere (color contours below with warmer colors indicating higher values)] across the state.  The dry air over western Utah and neighboring Nevada originates over the subtropical eastern Pacific and streams into the region from the southwest, whereas the moist air over eastern Utah and neighboring Colorado originates over the tropical Pacific and Gulf of California as well as th...

We are now half way through meteorological summer and the average temperature for June 1 – July 15 is tied with the same periods in 2013 and 2015 as the hottest ever in the Salt Lake City area with an average temperature of 78.1ºF. Source: NOAA Regional Climate Centers Both the average minimum and average maximum temperatures were well above the long-term average for the period, although it is the minimum temperatures that have really stood out compared to past summers. Source: NOAA Regional Climate Centers Source: NOAA Regional Climate Centers The traces above are based on records from Salt Lake Area stations, but exclusively records from the Salt Lake City airport beginning in 1928.  The impact of the station shift is very clearly illustrated by the abrupt drop in minimum temperature from 1927 to 1928. The airport is one of the coldest places in the Salt Lake Valley at night and shifting to that location yielded much lower minimum temperatures compared to the...

Lone Peak Wilderness Area, one of the great treasures of the central Wasatch Range In what I thought was something from News of the Weird, Senators Mike Lee (R-UT) and Orrin Hatch (R-UT) introduced the Human-Powered Travel in Wilderness Act yesterday, which would allow local land managers to potentially allow mountain biking in wilderness areas (see Mike Lee Press Release ).  My classification of this as a News of the Weird article is with all the issues that the two Senators deal with, I was quite surprised they've taken an interest in this one. As it turns out, I took a day of vacation and climbed the Pfeifferhorn yesterday with my son.  The Pfeifferhorn lies in the Lone Peak Wilderness Area, the largest wilderness area in the Wasatch Mountains.  In addition, the terrain between the Pfeifferhorn and Lone Peak is remarkably rugged and the most difficult terrain to access in the central Wasatch.   Looking west toward Lone Peak from the Pfeifferhorn reve...

Spoiler Alert : If you don't want to know what happened in today's (Wed 13 July) stage 11, read no further. Strong winds wreaked havoc on the Tour de France today, with the Peter Sagan (stage win) and Chris Froome (putting time on rivals) taking advantage. The weather is also expected to wreak havoc tomorrow and it has already been announced that the stage up Mt. Ventoux will stop at Chalet Reynard, about 500 vertical meters below the summit. The culprit is a strong Alpine lee cyclone that has developed on the south side of the Alps.  The 6-hour GFS forecast valid at 1200 UTC today (around the time of Stage 11) shows the classic signature that one sees when a cold front impinges on the Alps, stalls on the north slopes due to topographic blocking, and a variety of processes contribute to cyclogenesis to the lee near or over the Gulf of Genoa. The strong pressure gradient drives the strong Mistral (northwest) winds that affected Stage 11. For tomorrows stage 12, the ...

The large-scale circulation of the atmosphere undergoes substantial seasonal changes, especially in the Northern Hemisphere, home to a majority (68%) of our planet's land areas. The analysis below shows the average 500-mb heights over North America in July (the flow parallels the height contours with lower heights on the left).  During July, the storm track is displaced northward compared to its wintertime position and hugs the US–Canadian border.  Upper-level ridging lies over the Atlantic Ocean near 30ºC and extends westward over central North America, centered roughly on Texas.  This leads to easterly upper-level flow in the subtropics over the Caribbean, Gulf of Mexico, Mexico, and the subtropical east Pacific.  It is the development of this easterly flow during the summer, which contrasts with the westerlies found during winter over much of this region, that is characteristics of the  North American Monsoon system and a key reason for a pronounced summer ...

Yesterday wasn't a record setter at the Salt Lake Airport, but it was unusually cool for a sunny day and remarkably pleasant.  As a friend commented to me last night, "isn't September wonderful in Salt Lake City."  It sure is. For the average temperature for the day, one has to go back to 1983 to find a July 11 with a lower average temperature. Source: NOAA Regional Climate Centers For the maximum temperature, one has to go back to 1951 for a tie and 1936 for something lower. Source: NOAA Regional Climate Centers Most impressive to me is that the cool temperatures were associated with sunny skies rather than a rainy monsoon surge.  "Ah, what an airmass" as one of my former professors liked to say. But alas, September is over.  The good news is that it really doesn't look that bad the next couple of days with highs in the upper 80s (maybe mid 80s tomorrow).  The bad news is that we will be back to more seasonable weather (i.e., highs in th...

Here are a few perspectives on the wonderful July cold surge that we are enjoying today: 1. You earned it.  The summer so far (1 June – 10 July) is the hottest on record in the Salt Lake City Area with an average temperature of 78.5ºF.  The three hottest 1 June – 10 July periods on record occurred in the last 4 years. Source: NOAA Regional Climate Centers 2. It's an unusually cold airmass for July.  The 700-mb (10,000 ft) temperature in this morning's sounding from the Salt Lake City airport was -0.5ºF.  The all-time record low 700-mb temperature in the sounding record over northern Utah is -1.4ºF.  Although we didn't set a record, we are in rare territory as only 2 days previously in July saw a 700-mb temperature below 0ºC.  3. The valley temperatures are blissful.  Overnight minimums at valley locations include 51ºF at the Salt Lake City airport, 50ºF at the University of Utah, 48ºF at the Ogden airport (based on 5-min observations so un...

Northwesterly flow developed over the Salt Lake Valley this morning as the leading edge of cooler air began to penetrate into northern Utah.  Widespread northwesterly flow was apparent in the MesoWest surface plot just after noon. Source: MesoWest Sometimes cold air comes in with a bang, other times with a whimper.  This is a bit of a whimper as there wasn't a gangbuster frontal passage with a dramatic drop in temperature.  Nevertheless, the total change in temperature from yesterday to Monday is going to be quite large and around 25ºF for the valley. By tomorrow morning, forecast 700-mb temperatures (10,000 ft) are expected to be near or below 0ºC across northern Utah. The GFS (pictured above) is going for a 700-mb temperature of -1.3ºC for 6 am tomorrow morning at the Salt Lake City airport.  As discussed in the previous post, the lowest observed 700-mb temperature in the upper-air observing record for northern Utah in July is -1.4ºC, so we are going t...