Click the link to read the post on the Colorado Climate Center Blog (Peter Goble):

July 31, 2024

Recent Temperatures  

Colorado is currently in the throes of yet another heat wave. Many daily temperature records and some monthly temperature records will be threatened this week across northern and central Colorado. We will see temperatures flirting with the triple digits up and down the Front Range and Urban Corridor. The image below of the National Weather Service 5-day forecast for Denver shows persistent mid-to-upper 90s. 

Just earlier this month we saw a heat wave that threatened all-time high temperature records across the state (July 12^th – July 14^th). The details of the last heat wave can be found in our last blog. For this blog I thought it would be fun to explore heat waves in a bit more detail. First, we’ll examine some of the record heat from around the state. Then we will explore all the factors that need to come together to produce record heat. 

Records Around the State 

Most of the population centers in Colorado have all-time high temperature records between 100 °F and 110 °F. Records on the Urban Corridor from Fort Collins down to Colorado Springs range from 101 °F to 104 °F. Pueblo gets a bit hotter, with a record of 109 °F. The terrain in western Colorado is extremely complex, and so are the high temperature records. Areas in the valleys such as Grand Junction and Montrose have seen temperatures max out at values a little bit above the Front Range (107 °F and 106 °F respectively). The hottest temperatures ever recorded in Colorado have occurred on the Eastern Plains, with records from 109 °F to 115 °F in Las Animas; this is our state record. People travel from far and wide to enjoy our Colorado mountains in the summertime, and one of the biggest reasons is the thinner, cooler, drier air. Record high temperatures in the mountains are much cooler. Dillon, CO in Summit County has famously never experienced a 90-degree day. Maximum temperature records only get cooler as one travels higher in elevation. The figure below shows record high temperatures across the state. For the sake of comparison, I have also included the maximum temperature record of 80 °F at Slumgullion Pass, which sits at 11,300 feet elevation.  

We see in the figure above an obvious relationship between the maximum temperature record observed at a station and elevation. It is much more difficult to see extremely high temperatures in the thin mountain air than in the relatively think air over the eastern plains. This probably feels somewhat intuitive, but can we explain why this is using physics? Why can’t the mountains get as warm as the plains? Why are some summers hotter than others, and why are some heat waves worse than others? The remainder of this blog is devoted to examining the anatomy of a heat wave in detail, and understanding what weather forecasters might be looking for when forecasting in the heat of summer. 

Anatomy of Hot Temperatures – What causes the hottest weather on record, or even the hottest weather of the year, and how can forecasters see it coming? To produce the highest possible temperatures, we need several factors to come together: we need the right time of day, the right season, the right large scale atmospheric pattern, stable enough air, and the right microscale conditions. Let’s explore all of these factors! 

Time of day: Of course our hottest temperatures occur during the daytime when the sun is out, but how come the heat of the day occurs in the mid-to-late afternoon when the sun is shining most directly on us at noon? Whether or not the surface temperature is increasing or decreasing is determined by whether the earth’s surface is gaining more energy than it is losing. The energy input from the sun will be greatest at noon, but energy inputs continue to be greater than outputs throughout the afternoon, so the temperature continues to rise. This effect is shown in the figure below, which comes from a University Center for Atmospheric Research COMET module. The yellow curve shows the intensity of the sunshine throughout the day. The blue curve shows outgoing radiation, or how much energy is trying to escape from the earth’s surface out to space. As temperatures rise, this number goes up. You can think about it as the earth is “trying” to cool down. The red curve shows temperature throughout a typical day. If the yellow curve is above the blue curve, the temperature increases. If the blue curve is above the yellow curve, the temperature decreases. The maximum and minimum daily temperatures occur at overlapping points. 

If you live in Colorado, summer temperatures will probably top out some time between 3:30 and 5:00 PM in summertime. This is 2:30-4:00 in standard time, or approximately 2.5-4 hours after solar noon. We can see a good example of this using the Fort Collins weather station from our last heat wave on July 12th, 2024. The temperature climbed rapidly throughout the morning, becoming close to 100 °F by 1:00 PM MDT (12:00 PM MST, solar noon), and then slowly continuing to creep upward (with small fluctuations) for the next several hours. As late afternoon approached, the energy input from the sun could not keep up with the energy output from the earth’s surface and the temperature began to fall. 

Season: We all know summer is the hottest time of year, and most of us intuitively understand why: the days are longer and the sun shines more directly on the land surface during the day. We can put a little bit of math behind this intuition. When the sun shines from directly overhead, it sends 1366 Watts/meter squared of radiative energy though the top of the atmosphere. Some of this energy will be reflected or absorbed before hitting the earth’s surface, but on a clear sky day most of it will be absorbed by the land surface, and in turn, rapidly heat up the near surface atmosphere. The sun’s energy is not truly “constant,” it fluctuates based on sunspot cycles. For the moment, let’s just call maximum output from the sun 100%, and the amount of energy we get from the sun at night 0%.  

The fraction of the sun’s energy that reaches the earth’s surface is a function of angle: how high is the sun in the sky? When the sun is directly overhead it is intense and beats directly down on the land surface. When it is on the horizon the energy is diffuse, hitting with a glancing blow. The earth’s tilt is 23.5 degrees, so in the northern hemisphere, we tilt a maximum of 23.5 degrees toward the sun in the summer and 23.5 degrees away from the sun in the winter. This means if you live in Boulder, Colorado, which sits right on the 40^th, parallel, the sun will be 40 degrees south of directly overhead at midday on the spring and fall equinoxes, but 63.5 degrees from directly overhead on the winter solstice, and only 16.5 degrees from directly overhead on the summer solstice. We can take the cosine of these angles to see that the sun provides 77% of its maximum energy in Boulder at noon on either equinox, only 45% on the winter solstice, and 96% of its maximum energy on the summer solstice. 

Many of our most extreme heat waves across Colorado, and the country, do occur right around the summer solstice (late June), but may also occur throughout July and August. However, our heat waves are certainly not evenly distributed around the summer solstice. There are far fewer in late May and early June even though we receive more direct sunlight than we do in late July and early August. Why? Much as there is a lag between noon and the hottest time of day, a small lag exists between the longest, brightest days and the peak window for heat waves. It takes the atmosphere several weeks to fully equilibrate, or “catch up” to the increase in sunlight during late spring, making it easier to build “heat domes” later in the summer (more on this below). Furthermore, the land surface also tends to dry out as the summer wears on, meaning a greater fraction of the sun’s energy goes into directly heating the land, and a smaller fraction (on average) goes into evaporating water. All things considered, we end up with the largest threats for triple digit heat, in Colorado, in late June and July. The image below shows the official maximum daily temperature records for the Fort Collins weather station for every day of the calendar year. Our earliest 100-degree day on record is June 14^th, and our latest is August 1^st. 

We now know that the potential for record hot surface temperatures peaks in the mid-to-late afternoon in late June through late July, but can we explain why some days are hotter than others? Yes. The simple answer is we need the right weather conditions. Let’s explore the anatomy of a heat wave from a meteorological standpoint.  

Large-scale weather pattern: What large scale weather pattern is needed to produce heat waves? The short answer is dry air and high pressure, but we think about this in greater detail. We can think of earth’s atmosphere as being made of up airmasses and the boundaries between them. Air masses are large-scale high pressure systems that can be described as warm and dry (continental tropical, cT), warm and moist (maritime tropical, mT), cool and dry (continental polar, cP), or cool and (relatively) moist (maritime polar mP). Low pressure systems and stormy weather occur in the spaces between, where air masses collide with one another. The figure below shows different types of air masses, and where they tend to occur from Canada’s weather glossary. 

To obtain the hottest possible surface temperature we need a hot, dry, high pressure airmass to preside over Colorado. The air needs to be dry because moisture in the air can condense, forming clouds and blocking sunlight. If the near surface layer of air is too moist, thunderstorms will form when the air is heated, cooling conditions back down substantially. High pressure is ideal because air expands outward from high pressure centers, which leads to sinking air. Sinking air draws the driest air down from the upper atmosphere to the surface. Why is sinking air important? 

Stability: Have you heard the saying “heat rises?” If this is true, how are such high temperatures possible at the earth’s surface? Heat does indeed rise because hot air is less dense than cool air. However, as hot air rises it expands to equilibrate to the lower pressure at higher altitudes. There is an energy cost to air expanding, and because of this, air cools as it expands. When we measure this cooling, we see that rising air cools at a rate of 9.8 °C/kilometer of elevation gain (about 5.5 °F/thousand feet). The air aloft is usually cooler than the air at the surface, but so long as it is not more than 5.5 °F cooler per thousand feet of rise, the hot air at the surface will remain in place. This is why having relatively warm air aloft, and not just at the surface, is so important. If warm air is in place aloft, the air at the surface will have to be even warmer to rise.  

Stability is a big part of the reason high pressure atmospheric conditions are ideal for heat. As mentioned above, high pressure forces air aloft to sink. This air is compressed and warmed as it sinks, also at a rate of 5.5 °F/1000 feet. Hotter and drier than normal air above the surface, which is sometimes called a “heat dome,” suppresses the development of clouds and thunderstorms, forces air down from above that warms as it sinks, and lets the surface air bake to its maximum possible temperature under the hot summer sunshine.  

Stability is also why it is nearly impossible to generate triple-digit heat at high elevations. The thin air above our mountain valleys is so reliably cool. In the absence of a “heat dome,” the hot air generated at elevation usually rises and escapes, often triggering thunderstorms. Even record hot air near sea level is surprisingly cool if lifted to the elevations of our Rocky Mountains. For instance, suppose it is hot enough to produce a blistering 132 °F temperature at Furnace Creek in Death Valley. If that air was lifted to 2000 ft elevation, it would be 120 °F. As it happens, 2000 ft is the elevation of Las Vegas, and 120 °F is the all-time record high temperature in Las Vegas. Lift it another 3000 ft and you’re at the elevation of Fort Collins. That same air is now 103 °F. Hey, that is the record high temperature for Fort Collins! As it continues to rise, we hit a mark of 81 °F at 9000 ft (think Summit County) and 53 °F by the time we reach the elevation of Mt. Elbert, nearly 70 °F for just under three miles of vertical displacement. 

Thunderstorms can play a surprising role in producing heat waves. If there is too much moisture in the atmosphere, then heating up the land surface will generate thunderstorms, and kill any chance of developing record heat. However, thunderstorms that occurred earlier somewhere upstream can be a key ingredient for creating the perfect heat wave. Air in thunderstorm clouds is saturated, and as this air rises, it cools at a rate much lower than 5.5 °F/1000 feet. When saturated air rises the water vapor is condensed into liquid or even ice. This phase change of water from a gas to a liquid or solid releases latent heat of condensation, counteracting the cooling impact of air expanding as it rises. The image below shows an example of how moist air can return to the surface warmer than it started after releasing latent heat.  

The amount of latent, or “hidden” heat in moist air is enormous. If a saturated mass of air in the deep tropics was lifted high enough to condense all water vapor out of the air, and then forced all the way back down to sea level, it could be as hot as 200 °F. We never see air this hot because after moist tropical air is lifted, its density will be far too low to force all the way back to the surface. This air will have to cool for weeks if not months before returning to sea level. However, moist air that is lifted and releases its latent heat of condensation, and then is forced by high pressure to sink at least part way to the surface days later, can create a highly effective heat dome. This is what happened in the June 2021 heat wave over the Pacific Northwest. Storm activity over the Pacific Ocean lifted moisture-laden air into the upper atmosphere, releasing its latent heat. The now dry upper-level air traveled eastward until reaching the western United States. A high pressure airmass over British Columbia forced this air back down, creating a brutal heat dome over Washington and Oregon. 

Microscale weather pattern: The record high temperature for Denver is 104 °F, but have you ever driven by an area bank sign, or seen a car thermometer, that says 110 °F? Was that reading wrong? Not necessarily. If the sun is shining directly on the thermometer, then yes, it is wrong. Official temperature readings are taken in thermometer shelters, which are ventilated, but shaded (example below).  

If the thermometer is sited in a place with large amounts of asphalt/concrete/steel (e.g. downtown in a large city/Walmart parking lot) it may indeed be that hot! Long-term weather stations are supposed to be sited in more open spaces surrounded by native vegetation. If the temperature was 100 °F at a close by weather station maybe it was 109 °F where you parked your car. This is a well-known concern in large cities. All the concrete and steel and lack of green area traps heat, creating an “urban heat island.” The added heat in structure-dense cities is a major health and human safety concern in many metro areas around the country.  

Climate change: To quote a recent article on heat waves by Dr. Andrew Dressler “a rising tide floats all boats.” More heat in the atmosphere means a higher upper bound on how hot temperatures can get. That said, while we are seeing significant increases in the number of hot days (figure below) we are not seeing such obvious movement in record high temperatures. 

Conclusion: All things considered, when will you see record heat, and why? 1. Record heat will likely occur in the mid-to-late afternoon immediately after the day’s peak heating hours. 2. Record heat will probably occur in late June or July. August is hot, but the days are already getting shorter, and the intensity of the midday sun has already begun to wane. 3. The air and land will be dry. In Colorado, it is almost impossible to heat humid air to triple digits without clouds forming, and possibly thunderstorms. 4. The surface pressure will be high, which draws dry, compressed air down from the upper atmosphere at seals in warmer conditions. 5. The air above the surface can likely be traced back to thunderstorm activity somewhere else. The latent heat release from these storms is contributing to the heat dome over your head. 6. If a new record occurred at your local long term weather station, it was probably even hotter downtown and on the roadways. 

Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor website.

Click the link to go to the US Drought Monitor website. Here’s an excerpt:

This Week’s Drought Summary

Heat continued to be the dominating feature in the Southwest and Plains. Temperatures were 2 to 6 degrees above normal, with isolated areas seeing temperatures of 6 to 8 degrees above normal. The Southwest reached near record temperatures once again, with the highest 1-day maximum temperature for the week reaching 120 degrees in Death Valley and 110 degrees in surrounding areas. The West and Plains missed out on much of the precipitation that fell this week. These hot and dry conditions have leant themselves to increased fire potential and wildfires. The southern Plains, missing out on the precipitation and experienced above-normal temperature, leading to more drying and degradation. Similar degradations occurred along the western border of the High Plains due to the lack of precipitation, poor soil moisture, and declining streamflows. The Southeast on the other hand received substantial precipitation, vastly improving lingering dryness in the area. The northern Appalachian region saw 1-category degradations where streamflows in north-central West Virginia are critically low…

High Plains

The High Plains received trace amounts of precipitation, leading to already dry conditions in the western and southern High Plains to further deteriorate. Poor soil moisture in much of Kansas brought about widespread 1-category degradations. In eastern Kansas, along the Missouri border there have been reports dryness and heat stress. Central Kansas has also seen reports of dry ponds and fear of total crop failures. Some of these drier conditions spilled northward into southern Nebraska, which also saw areas of the northeast and western Panhandle deteriorate because of an extended period of dry conditions, dry vegetation, and low streamflow values. Similar conditions were seen across western South and North Dakota and Wyoming. Colorado saw deterioration in the northern Front Range, where extreme temperatures and low humidity made for perfect conditions for wildfires. Two fires were reported on Monday July 29: the Alexander Mountain Fire west of Loveland, the Stone Mountain Fire southeast of Estes Park…

West

The Northwest saw some relief from the extreme heat this week, with temperatures in Nevada, California, Oregon, and Washington being 2 to 6 degrees below normal. Conversely, the Southwest saw more extreme heat. Southern California, the southern tip of Nevada, and western Arizona saw temperatures of over 90 degrees this week with the highest 1-day maximum temperature reaching over 110 degrees. In the northern West, Montana saw slight improvements in the far north where temperatures were slightly below normal but saw similar conditions as North and South Dakota conditions in the central and eastern parts of the state. Central Utah saw minor expansion of abnormal dryness as streamflow began to drop and vegetation is looking dry…

South

Eastern portions South saw much of the heavy precipitation seen in the Southeast. Southeastern Texas into western Louisiana recorded areas of over 8 inches of rain falling this week. There was a sharp line of where the precipitation fell and did not. West of south-central Texas, northeastward to central Arkansas saw trace amounts of rain. Temperatures were also between 1 and 4 degrees below normal, with eastern Texas and western Louisiana having temperatures of 6 to 8 degrees below normal. Except for north-central Texas and parts of Oklahoma, and western Arkansas, 1-categoy improvements were made. Oklahoma saw a mixture of above- and below-normal temperatures, with hot temperatures heating up at the end of the week (July 23 to 30). Reports of “cover crops being cooked” and “no soil moisture for native grasses to draw from and large pastures have lost much green color and have shrunk considerably” in central Oklahoma’s Logan County…

Looking Ahead

Over the next five days (August 1-6), the Midwest, Northeast, and eastern Southeast are expected to see 1 to 2 inches of rain with heavier amounts predicted in the eastern Midwest and southern Florida. The rest of the Southeast will see more modest amounts of precipitation, deviating from their previous weeks of heavy precipitation. There is currently an Atlantic Disturbance that the National Hurricane Center show a greater than 60 percent chance of developing into a tropical cyclone within the next two days (August 1-2) which could bring heavy rainfall along the Atlantic Coast in the coming week. Isolated areas from Wisconsin, Minnesota, and Iowa to Kansas and higher elevations of Colorado, New Mexico, and Arizona are expected to receive around 1 inch of precipitation. Otherwise, precipitation will be light and spotty leading to much of the West, Texas, southern Oklahoma and Arkansas missing out on the precipitation.

The National Weather Service Climate Prediction Center’s 6-10 day outlook heavily favors above-normal temperatures from the Pacific Northwest across to the Southeast with conditions becoming near normal across the central U.S. and leaning to below normal temperatures further north toward Canada. Much of Alaska is expected to be above normal with below-normal temperatures possible to the southwest. Similarly, Hawaii is leaning towards above-normal temperatures. Many of the lower 48 states are leaning towards above-normal precipitation, centering around Wyoming and Colorado, along with the Atlantic Coast, which could see remnants of the Tropical Disturbance currently in the Caribbean. Alaska’s border with Canada is seeing up to a 70 percent chance of below normal precipitation, with the probability increasing in the west and southwest. Hawaii probability of seeing below-normal precipitation is 33 to 40 percent.

Click the link to read the article on the WyoFile website (Kerry Drake):

July 30, 2024

It’s not enough to be afraid of the Heritage Foundation’s Project 2025, a blueprint for Donald Trump’s White House return. Terrified is more like it.

The 900-page treatise spells out a plan to turn the United States into a MAGA paradise. That may sound like ecstasy to many Wyomingites who gave Trump his largest state margin of victory in his 2020 failed reelection bid, but it would crash the federal government beyond repair.

That wouldn’t be a good look for a state whose budget relies so heavily on funding from the federal government, but Wyoming’s dismal fiscal future is not the scariest thing on the horizon if Project 2025 gains traction.

It promotes an agenda that stands the idea of separation of church and state on its head, and rewrites federal laws to follow the guiding principles of Christian Nationalism. It throws democracy under the bus and takes away freedoms guaranteed in the Bill of Rights. 

Project 25 claims it wants to restore “God-given rights,” but its authors don’t mention those rights would only be guaranteed for those who worship the deity that has the federal government’s stamp of approval.

The Heritage Foundation, a far-right “think tank,” has produced similar manifestos since the 1970s. It must have worked overtime to create a controversial new vision of government that is anti-public education, anti-public health, anti-environment, anti-non-Christians, anti-abortion, anti-LGBTQ, anti-immigration and anti-federal workers.

What does Project 25 favor in addition to targeting all of the above? Not surprisingly, the plan endorses cutting taxes for the wealthy, matching the primary goal of the first Trump administration. The Heritage Foundation and 100 other right-wing groups that signed on want to finish Trump’s border wall.

Convicted felon Trump backs many of these proposals, including the National Guard and federal agents rounding up and deporting more than 10 million people who aren’t in this country legally. Wyoming residents in favor of kicking out all non-citizens should realize mass deportations will likely include their friends, co-workers and even family members.

Project 2025 wants to eliminate the U.S. Department of Education, end federal public school funding and send the money to private and religious school voucher programs. Wyoming’s Legislature already went down this path by creating “education savings accounts.” 

Do you want to enroll your child in Head Start? Forget about it, because the program won’t exist.

Trump has gone to absurd lengths to drive his golf cart away from the stench of Project 2025 as fast as he can because so many of its recommendations are extremely unpopular.

Don’t be fooled; he’s in bed with these guys. “This is a great group, and they’re going to lay the groundwork and detail plans for exactly what our movement will do,” Trump said at a 2022 Heritage Foundation dinner.

His biggest whopper, though, was this denial: “I know nothing about Project 2025,” Trump wrote on his Truth Social website. “I have no idea who is behind it. I disagree with some of the things they’re saying and some of the things they’re saying are absolutely ridiculous and abysmal. Anything they do, I wish them luck, but I have nothing to do with them.”

Soils dried in the Pacific Northwest, Plains, & parts of the Midwest. Big improvements in topsoil conditions for much of the Southeast.

Click the link to read the blog post on the Colorado Climate Center website (Russ Schumacher):

July 23, 2024

Leading up to the weekend of July 12-14, weather forecasts were indicating the potential for extreme heat in parts of Colorado. I was getting messages from people saying that their weather apps were showing that all-time records would be broken by multiple degrees (which mostly warranted an eye-roll.) On both Saturday the 13th and Sunday the 14th, there were just enough afternoon clouds and showers to keep the temperatures from reaching historic highs. But it was still a noteworthy heat wave, especially along the Front Range. Fort Collins reached a high of 102°F on Friday the 12th, one degree shy of the all-time record, and only the 7th time in over 130 years of records it had been that warm. That same day, Colorado Springs reached 100°F for only the 12th time, also one degree shy of the all-time record.

Below are maps of the average temperature for the four-day period from the morning of Friday the 12th through the morning of Tuesday the 16th, and how it compares to the 30-year “normal” for those four days.

The very highest temperatures over this period were in some of the usual places at lower elevations, like the Arkansas Valley in southeast Colorado, and the Grand Valley on the western slope. But because these are Colorado’s usual hot spots, the heat wave wasn’t as extreme compared to average in those areas. The mountains provided their usual respite from the heat. (The long-term station at Dillon made it up to 84°F, which is pretty warm for a location that has never recorded a 90-degree day.) The temperature anomaly map shows that the Urban Corridor saw the most unusually hot conditions. From the Palmer Divide down through Pueblo County, most locations were more than 8°F above average over these four days.

How does this compare to past heat waves?

To address this question, we will build upon the analysis in the Climate Change in Colorado report, which looked at trends in four-day heat waves using NOAA’s nClimGrid-daily dataset, which goes back to 1951. In that analysis, we divided up Colorado into 11 alternate climate divisions, which better represent climate variability than the official divisions that are defined by river basins. (Interested in the details on this? We just had a paper published describing the method and results.) The map below shows where this heat wave ranked in those alternate climate divisions.

It wasn’t a record-breaker in any of the regions, but in the Northern Front Range and Pikes Peak regions, it was a top-10 four-day heat wave. Averaged across the entire state, it ranked as the 14th hottest 4-day heat wave since 1951. So, perhaps not one for the history books, but still worthy of the attention it received. You might then wonder, when were the heat waves that ranked at the top?

Pretty much everywhere in the state, the top-ranked four-day heat wave was from June 24-27, 2012. During this time period, multiple intense wildfires were raging across the state, including the Waldo Canyon fire that devastated neighborhoods on the west side of Colorado Springs. In second place statewide and in both the Pikes Peak and Northern Front Range climate divisions was in July 2005. Fort Collins set its all-time record high of 103°F during this heat wave. Mid-July of 1954 also shows up on these lists: many Front Range stations had their longest streaks of 100-degree days during that heat wave, although the nighttime lows were a bit cooler than the others so it doesn’t rank at the top overall.

What about the 1930s? What about climate change?

The nClimGrid-daily dataset, which features consistent data processing to allow for analysis of long-term changes, only goes back to 1951, which means it does not include the “dust bowl” era of the 1930s, during which intense heat and drought afflicted the Great Plains. At some individual long-term stations on Colorado’s eastern plains, heat waves in July of 1934 and 1936 still rank as hotter than those in more recent years (although at other stations, those records were surpassed by the June 2012 heat wave.) Grand Junction’s hottest 4-day period came in late July of 1931. Bob Henson and Jeff Masters at Yale Climate Connections recently published an insightful article on why the 1930s were so hot in North America, which includes the effects of poor soil management practices in the Great Plains.

We also know that the climate is warming, and that the frequency of heat waves is increasing in the western US. Most regions of Colorado saw significant increases in the number of heat waves from 1951-2020 (the exceptions being the central mountains, and the northeastern and southeastern plains). And these trends continue: the right panel below shows an updated graph for the Pikes Peak region through the present. The first 3+ years of the 2020s already had 12 heat waves in this region, which is more than than any full decade between the 1950s and 1990s. Future climate projections show that the frequency of heat waves is expected to increase much more, even in a moderate-emissions scenario.

Overall, what we’ve seen in Colorado isn’t that the most-extreme heat waves are getting more extreme. Record-smashing events are very rare even in a warming climate, and when air masses are hot enough aloft to have the potential for record-breaking heat, they often have just enough moisture to produce clouds and storms that reduce the surface temperature by a degree or two. Instead, what we’re seeing is a steady increase of heat: heat waves that would have been few and far between in the 20th century are now becoming commonplace. (I was able to do an extended interview on this topic on Colorado Public Radio’s Colorado Matters program that you can listen to here.)

A concluding note is that even with this heat wave in the middle of the month, July as a whole has not actually been especially warm across Colorado. Many stations are near to even a little below normal for temperature for the month, with the refreshing weather around the 4th of July and the cooler, wetter conditions this past weekend. However, the last week of the month looks like it will bring more hot, dry weather. This may end up putting July above average for temperature when the month concludes, and could add to the tally of heat waves in Colorado as well.

Click on a thumbnail graphic to view a gallery of drought data from the US Drought Monitor website.

Click the link to go to the US Drought Monitor website. Here’s an excerpt:

This Week’s Drought Summary

Over the past week, a major heatwave brought warmer-than-normal temperatures to much of the West, with departures ranging between 3 to 12 degrees F above normal across much of the region. Near-normal to cooler-than-normal temperatures were observed from the central Rockies to the Great Lakes, with departures ranging between 3 to 9 degrees F below normal. Precipitation varied across the contiguous U.S. this week. Monsoonal moisture brought heavy precipitation and flash flooding to parts of the Southwest, while a lingering frontal boundary brought daily thunderstorms, heavy rainfall and flash flooding across much of the Southeast and Mid-Atlantic. The most widespread improvements were made in the Southeast, as well as eastern portions of the Southwest and across much of western Texas, where above-normal precipitation amounts were observed this past week. Conversely, dry conditions resulted in degradations across much of Hawaii and the Pacific Northwest, as well as southern portions of the Northeast and in parts of the central Plains, and other parts of the West. Drought and abnormal dryness also expanded or intensified in the Ohio Valley, western High Plains, and in New England. In Hawaii, dry conditions coupled with warmer temperatures resulted in the expansion and intensification of drought across the state this week…

High Plains

Precipitation fell across much of the region this week, which was enough to prevent large areas of degradation but not enough to warrant large improvements. The heaviest rainfall amounts fell across much of eastern Colorado, reporting rainfall totals up to 400% of normal, resulting in the improvements of abnormal dryness and the removal of moderate drought from the region. Heavy precipitation amounts were also reported in central Nebraska and central South Dakota but were already free of drought and abnormal dryness this week. Precipitation was below-normal across the western portions of the region, resulting in the expansion and intensification of drought. Severe drought was added western South Dakota and Nebraska, and expanded in eastern Wyoming. Moderate drought also introduced in southwest Nebraska this week, while abnormal dryness was expanded in the area. Much of the region remains free of drought and abnormal dryness this week…

West

Average temperatures were well above normal across much of the West this week. Temperatures ranged between 3 to 9 degrees F above normal across much of the region, while northern portions of the region observed temperatures up to 12 degrees F above normal this week. Precipitation fell across much of the region but amounts were mostly below-normal for the region. The heaviest precipitation amounts were measured over parts of New Mexico. Above-normal precipitation (up to 6 inches), along with cooler temperatures, resulted in the removal of exceptional drought from southeast New Mexico and improvements to extreme drought, severe drought, moderate drought and abnormal dryness across eastern and southern portions of the state. Conversely, warmer-temperatures and below-normal precipitation resulted in the introduction of exceptional drought in western Montana, as well as the expansion of drought in other parts of Montana, across much of Oregon into northern California, while moderate drought was introduced in northwest Utah. The expansion of abnormal dryness occurred in parts of Nevada, which missed out on some of the beneficial rains resulting in the expansion of moderate drought in the area. Conditions remained dry in the interior parts of Washington, resulting in expansion of moderate drought and abnormal dryness based on short-term SPI/SPEI data, as well as low soil moisture and streamflow…

South

Dry conditions continued across much of the northern portions of the South this week, while heavy precipitation fell across much of central Texas and in parts of northern Arkansas, with areas reporting rainfall totals greater than 600% of normal. Abnormal dryness was removed from northern Arkansas, while moderate to extreme drought were improved across much of central Texas. Improvements were also made to parts of northern and eastern Tennessee where spotty showers brought much needed relief, returning areas back to their 30-day precipitation normals. Conversely, conditions continued to deteriorate in parts of northern Kansas and parts of western Texas, where precipitation totals were 5% to 25% of normal for the past month. Moderate to severe drought were expanded into central Kansas, while extreme drought was expanded and exceptional drought was introduced into the Trans-Pecos region of Texas this week. Temperatures were below-normal across much of the South, while departures of 1 to 6 degrees F above normal were observed across parts of western Texas. The expansion and intensification of drought categories were based on short-term SPI/SPEI, reservoir levels, streamflow and soil moisture data…

Looking Ahead

During the next five days (July 23–27, 2024), dangerous heat is expected to continue through the midweek across much of the West, with high temperatures reaching the 90s and 100s and ranging between 5-15 degrees above normal. The strong ridge, extending from the Southwest U.S. into west-central Canada, which produced hazardous heat from the West into the northern High Plains, should begin to weaken and begin to push eastward ahead of a Pacific upper low tracking into western Canada and trailing trough that will settle near the West Coast. Monsoonal conditions will promote daily episodes of showers and storms over the Four Corners states and into the Great Basin under and near upper ridging over that part of the country. Meanwhile, one or more wavy fronts will be on the leading side of Great Lakes into southern Plains mean troughing aloft, leading to multiple days of rain and thunderstorms with areas of heavy rainfall from the southern Plains into the Mid-Atlantic and parts of New England. The Great Lakes and Northeast should eventually trend drier late week as the northern part of the trough moves eastward. Consensus still shows the Atlantic upper ridge building into the Southeast for a time, peaking in strength around Wednesday-Thursday.

The Climate Prediction Center’s 6-10 day outlook (valid July 28–August 1, 2024) favors above-normal precipitation along much of the eastern contiguous U.S. and Alaska, as well as parts of Northwest, with below-normal precipitation across most of the interior West and in parts of New England. Increased probabilities for above-normal temperatures are forecast for much of the contiguous U.S., while below-normal temperatures are likely across the state of Alaska and in southern parts of California and Texas.

Click the link to read the article on the High Country News website (Anna V. Smith and Erin X. Wong):

July 22, 2024

On July 21, President Joe Biden withdrew from the 2024 presidential race and endorsed Vice President Kamala Harris to run in his place, launching her to the forefront of potential Democratic nominees. Harris’ term as VP hasn’t produced many significant policy outcomes of her own, but her experience as a California senator and attorney general, as well as her 2020 presidential campaign, point to a consistent record of pro-climate, pro-environmental policies and an evolved understanding of tribal land issues. Should she eventually assume the Oval Office, her career to date signals a likely continuation of the West’s Biden-era gains in the protection of public lands, water and wildlife as well as support for tribal sovereignty.  

“We couldn’t be more excited,” said Athan Manuel, director of the Sierra Club’s lands-protection program. Harris worked with the organization on bills to expand California’s public lands, increase access to nature and develop community incentives for wildfire prevention. “She understood the totality of these issues, and that gives us great confidence.”

Over the past four years, the Biden administration reinstated protections for Alaska’s Tongass National Forest and conserved more than 41 million acres of public land. It passed the climate-forward Inflation Reduction Act, which was hailed as a windfall for domestic clean energy jobs and a once-in-a-generation wealth transfer to historically marginalized communities. The record bears a striking resemblance to Harris’ own platform for president, which also pursued environmental justice and sought an end to fossil fuels on public lands.

“This was the most impactful one-term presidency on public lands, climate change and environmental justice,” Manuel said. Harris, who was born in Oakland and spent much of her career in California, was also able to provide the Biden administration with insight into regional issues. “A Westerner leading on all these issues is very significant.”  [ed. emphasis mine]

Prior to joining Biden’s ticket, Harris was best known as a Golden State prosecutor. As California’s attorney general, Harris won multiple settlements against corporate polluters, including a $44 million settlement from the owners of a container ship that spilled 53,000 gallons of oil into the San Francisco Bay. She secured multimillion-dollar deals with oil companies BP, ARCO and ConocoPhillips for negligent monitoring of hazardous materials in gas station storage tanks, and she was part of the team that held Volkswagen accountable for bypassing air pollution regulations, eventually earning more than $86 billion in penalties for the state. However, her claim that she pursued polluters while working in the San Francisco DA office has come under scrutiny.

In the Senate, she co-sponsored bills to develop national wildlife corridors, divert revenue from energy development to national parks and further climate equity by calculating policy impacts on frontline communities. She voted to protect the Antiquities Act and the Great American Outdoors Act, as well as to halt drilling in the Arctic and pass a public-lands package that conserved 2 million acres of land and water. Over the course of four years, she earned multiple perfect scores from the League of Conservation Voters.

Harris’ track record with Indigenous affairs over her decades working in politics is more varied. As state attorney general, she created the first Indian Child Welfare Act Compliance Task Force to protect Native children. But she also opposed multiple tribal applications to put land into “trust” and thereby grow a tribe’s land base. During her time as attorney general, Harris’ office also pursued a legal argument that could have had negative, precedent-setting impacts for tribes that have acquired land in trust. She argued that the Big Lagoon Rancheria, a tribe that was seeking to build a casino on 11 acres of trust land, improperly received that land from the federal government. The case had the potential to open past land-to-trust transfers across Indian Country to litigation, but the 9th Circuit Court of Appeals ultimately ruled against California.

Since then, Harris has distanced herself from that position. When then-Cheyenne River Sioux Tribal Chairman Harold Frazier asked her about this publicly in 2019, Harris said that as California’s attorney general it was her duty to represent the state’s interests, which did not necessarily reflect her own. “As California’s attorney general she was perceived as being more focused on states than tribes,” wrote Mark Trahant (Shoshone-Bannock) in an analysis for ICT. “But that has largely shifted.”

During her 2020 campaign for president, for example, Harris promised to assist tribes in restoring their lands and to make it easier for them to do so in the future. Her campaign also detailed specific policies and initiatives to advance Native voting rights, increase funding for the federal agencies serving tribal communities, and protect Native women and children, building on some of the legislation that she co-sponsored during her time in the Senate. Those bills largely focused on supporting Native health care and addressing the crisis of Missing and Murdered Indigenous Peoples, along with the Native Voting Rights Act of 2019 and other legislation concerning tribal wildlife corridors and food sovereignty. 

As vice president, she’s been a part of an administration that has made considerable strides in integrating Indigenous knowledge and tribal priorities into public-lands management, as well as in providing funding for Native-led climate resilience projects and appointing multiple Indigenous people to leadership positions. She was the first sitting vice president to visit the Gila Indian River Community and do an interview with the Native news organization ICT. Asked by reporter Aliyah Chavez (Kewa Pueblo) about the administration’s goals and the decision to appoint Native leaders like Interior Secretary Deb Haaland (Laguna Pueblo), Harris said, “I do believe that we are setting a new model for what the interaction and what the partnership should be [with tribes], always grounded in full appreciation and respect for tribal sovereignty.” 

The Democratic Party has less than a month to introduce any alternative candidates before the Democratic National Convention on Aug. 19. Other potential frontrunners, including California Gov. Gavin Newsom, appear to be rallying behind Harris as the primary candidate who could win the race against former President Donald Trump. 

Spots of both improvement and drying in the East and Southeast, while much of the West and Plains dried out. Greatest drying this week was in RI, CT & WA.