Why Do Leaves Change Colors in the Fall? Using Satellite-Based Wind Lidar to Improve Hurricane Forecasts

Falls Colors Peaking Over Minnesota Arrowhead

The outlook for the next few weeks calls for a blizzard of color, caravans of determined leaf-peepers, and backyard workouts involving rakes. The leaves are leaving, but not before a crescendo of color, nature’s exclamation point, coming at the end of the hottest summer on record for Minnesota and the nation.

Colors are peaking over the Minnesota Arrowhead, but the most vibrant hues of magenta, rust and lemon may be 2 weeks away in the metro area. Trees are stressed from the ongoing drought, so colors may be more muted than previous years, but it should still be quite a show. Good luck.

A flawless Thursday is on tap – arguably one of the nicest weather-days of 2021. Cooler air dribbling south sparks a few showers and more wind tomorrow, but skies mellow over the weekend. Sunday still looks like the sunnier, milder day of the weekend, in fact next week may be 10-15F warmer than average with a few shots at 80F. Not too shabby, considering the sun angle is the same as March 20.

Soak it up while you can.

A Good-Looking Thursday. Expect blue sky and a lukewarm breeze today, arguably the nicest weather-day of the week with afternoon temperatures a few degrees above average. A closed low will lash Michigan and eastern Wisconsin with a few showers today and Friday, and we can’t rule out a splash-and-dash shower across Minnesota tomorrow as cooler air moves in.

Friday Showers. Just about the only chance (opportunity) for rain looking out the next week comes on Friday as a weak cool front pushes across the state on gusty northwest winds. Any rainfall should be light and spotty.

Smooth Sailing. In spite of a brief cool-down (60s Friday and Saturday) temperatures trend above average Sunday into next week. The downside: a shower is possible Friday and Saturday, but the first chance of widespread/significant rains won’t arrive until late next week.

No Sustained Canadian Slaps Into Early October. GFS guidance predicts a few cut-off lows over the continental US, where temperatures trend milder than average the next few weeks. Any significant blasts of chilly air will remain well north of the Canadian border into mid-October, based on all the guidance I’m looking at.

September Rainfall Surplus for Central Minnesota. Here’s a nice switch: a wetter than average month from St. Cloud and Brainerd to Duluth, Park Rapids and International Falls. We are taking (baby-steps) toward pulling out of the drought, but it will take months for soil moisture and water levels to get back to where they should be.

Extreme Heat Hits 30% of Americans This Summer. Nexus Media News has the details: “Nearly one-third of all Americans live in a county hit by an extreme weather disaster in the past three months, with far more living in places that have endured a multi-day heatwave, a Washington Post analysis revealed. Climate change, caused by the extraction and combustion of fossil fuels, is supercharging heatwaves, hurricanes, wildfires fueled by drought, and extreme precipitation that causes flooding. Those phenomena have killed at least 388 people in the U.S. since June…”

New Forecasting Models Could Help Prevent Heat-Related Deaths. Here’s an excerpt of an explainer at phys.org: “...Of all the natural disasters occurring in recent decades, heatwaves have caused the greatest loss of human life. And, as temperatures continue to increase, more lives will be put at risk. The key to saving lives is the use of accurate and reliable weather prediction models that go well beyond today’s standard weekly forecasts. One such model is sub-seasonal to seasonal (S2S) forecasting. Falling between weather forecast models, which predict the weather over the next week or so, and climate models, which predict the average weather, or climate, over many years, S2S forecast serve as extended weather forecasts…”

Hurricanes, Floods, Wildfires and Extreme Heat: A Time-Line of 2021’s Devastating Weather Events, To Date. It’s a long list, courtesy of Forbes; here’s a clip: “…The average temperature for the lower 48 states during the 2021 meteorological summer (June to August) was 74 degrees, which is 2.6 degrees above average, tying it for the warmest summer on record, according to the U.S. National Oceanic and Atmospheric Administration, which also notes this summer’s ranks as the eighth wettest on record. Each of the past six years has been among the hottest on record, with 2020 tying 2016 as the hottest year ever, according to Copernicus Climate Change Service, climate researchers based in Europe. A separate recent study conducted by 70 researchers using updated epidemiological and climate modeling data in 43 countries found that 37% of heat-related deaths are attributable to increased warming associated with climate change…”

Artist impression of Aeolus satellite with a Doppler Wind Lidar.

Study on the Best Way to Improve Forecasts Using a Proposed Satellite-Based Doppler Wind Lidar. Here’s an excerpt from NOAA’s Hurricane Research Division: “Accurate forecasts of the future weather depend on observing what is happening now in the atmosphere. There remain many gaps in our current observations, especially over the oceans where most measurements come from satellites. An instrument that could measure the winds at many levels through the atmosphere (called a Doppler Wind Lidar) could be placed on satellites in the future to fill this gap. These wind profiling instruments on satellites that orbit the earth may provide frequent observations of what is happening currently in the atmosphere. This could lead to more accurate forecasts by the numerical models used by forecasters to make their predictions. A Doppler Wind Lidar currently exists on a satellite that circles the earth (polar-orbiting satellite) and observes a single line of wind profiles...”

Long Waits to Connect to Xcel’s Grid are Stalling Minnesota Solar Projects. Energy News Network has the details: “The number of Minnesota solar projects stalled due to delays by Xcel Energy has ballooned to more than 300, with a backlog of applications that solar industry leaders say will take decades to clear at the utility’s current pace. In one case in central Minnesota, Xcel told a customer they would have to wait 15 years for the company to review their application to connect a 9.5-kilowatt rooftop system to the utility’s distribution grid. “This is the number one issue I hear about from our members. I get emails every day about this,” said Logan O’Grady, executive director of the Minnesota Solar Energy Industries Association…”

A dog nibbles on black soldier fly larvae.

Pets Can Help Fight Climate Change with an Insect-Based Diet. I have to think about this one. The Washington Post (paywall) has the lip-smacking details: “…Many pet owners reflexively bark “No!” when their dog or cat prepares to feast on a bug. But despite what scientists call the “yuck factor,” insects could be a sustainable secret ingredient for the booming pet food industry. About a quarter of Americans are cutting back on eating meat, many alarmed by the fact that livestock farming causes up to 15 percent of global greenhouse gas emissions. Yet for all the humans observing meatless Mondays, opting for Impossible burgers or swearing off meat entirely, 180 million furry members of U.S. households are fed beef, lamb, poultry or pork in just about every meal. Researchers at the University of California at Los Angeles estimate that dogs and cats account for up to 30 percent of the environmental impact of U.S. meat consumption...”

The 12th version of Samuel Adams’ Utopias beer, which be released Oct. 11, contains 28% alcohol by volume, making it illegal to sell in 15 states.

Samuel Adams’ Latest Potent Beer is Illegal in 15 States. Minnesota is not one of them. UPI.com has the story: “The latest beer from Boston brewer Samuel Adams bears a piece tag of $240 per bottle and bears another notable distinction: it’s illegal in 15 states. Samuel Adams said the 12th version of the Utopias brand, which the brewery rolls out every two years, will roll out Oct. 11 at a price of $240 for 25.4-ounce bottle. The beverage contains 28% alcohol by volume, more than five times the average strength of U.S. beers, making it illegal to sell in Alabama, Arkansas, Georgia, Idaho, Missouri, Mississippi, Montana, North Carolina, New Hampshire, Oklahoma, Oregon, South Carolina, Utah, Vermont and West Virginia...”

71 F. Twin Cities high temperature on Wednesday.

71 F. average MSP high on September 22.

83 F. high temperature on September 22, 2020.

September 23, 1995: 0.2 inches of snow falls in the St. Cloud area.

September 23, 1985: Early snow falls over portions of Minnesota and western Wisconsin. Just under a half inch (0.4) is recorded at MSP Airport, mostly during the afternoon.

September 23, 1937: From summer to winter. The temperature was 101 at Wheaton. Then a cold front came through causing the mercury to tumble below freezing.

THURSDAY: Sunny and beautiful. Winds: S 5-10. High: 73

FRIDAY: Windy with a passing shower. Winds: NW 15-25. Wake-up: 54. High: 65

SATURDAY: Partly sunny and breezy. Winds: W 10-15+ Wake-up: 49. High: 67

SUNDAY: Sunny, even nicer. Winds: SE 8-13. Wake-up: 54. High: 79

MONDAY Plenty of lukewarm sunshine. Winds: SE 8-13. Wake-up: 56. High: near 80

TUESDAY: Sunny, still close to perfect. Winds: SE 5-10. Wake-up: 58. High: 78

WEDNESDAY: Blue sky, distractingly nice. Winds: SE 5-10. Wake-up: 60. High: 81

Climate Stories…

United Nations Secretary General Antonio Guterres addresses the 76th Session of the U.N. General Assembly, Tuesday, Sept. 21, 2021, at United Nations headquarters in New York.Eduardo Munoz/Pool Photo via AP

“The World Must Wake Up”: Tasks Daunting as UN Meeting Opens. Here’s the intro to a recap at Associated Press: “In person and on screen, world leaders returned to the United Nations’ foremost gathering for the first time in the pandemic era on Tuesday with a formidable, diplomacy-packed agenda and a sharply worded warning from the international organization’s leader: “We face the greatest cascade of crises in our lifetime.” Secretary-General Antonio Guterres rang the alarm in his annual state-of-the-world speech at the opening of the U.N. General Assembly’s high-level meeting for leaders of its 193 member nations. More than 100 heads of state and government kept away by COVID-19 are returning to the U.N. in person for the first time in two years. But with the pandemic still raging, about 60 will deliver pre-recorded statements over coming days. “We are on the edge of an abyss — and moving in the wrong direction,” Guterres said. “I’m here to sound the alarm. The world must wake up...”

File imageNASA Earth Observatory

Summer Wildfires Emitted More Carbon Dioxide Than India Does in a Year. Gizmodo has the story; here’s the intro: “The world set a scary new record last month: Wildfires around the world pumped out more carbon dioxide than ever before. Forests on multiple continents went up in smoke, spewing out billions of tons of carbon dioxide, new data from the Copernicus Atmosphere Monitoring Service shows. In July, wildfires emitted nearly 1.3 gigatonnes of carbon dioxide, a record that was topped by August’s 1.4 gigatons. Between the two months, forest fires emitted an amount of carbon dioxide greater than all of India’s carbon emissions in a year. The majority of those emissions came from wildfires two regions, western North America and Siberia. Blazes in both regions were fueled by heat waves, drought conditions, and low soil moisture levels—three hallmarks of the climate crisis…”

Big Tech’s Pro-Climate Rhetoric is Not Matched by Policy Action, Report Finds. The Guardian has the post: “The world’s biggest tech companies are coming out with bold commitments to tackle their climate impact but when it comes to using their corporate muscle to advocate for stronger climate policies, their engagement is almost nonexistent, according to a new report. Apple, Amazon, Alphabet (Google’s parent company), Facebook and Microsoft poured about $65m into lobbying in 2020, but an average of only 6% of their lobbying activity between July 2020 and June 2021 was related to climate policy, according to an analysis from the thinktank InfluenceMap, which tracked companies’ self-reported lobbying on federal legislation. The report also sought to capture tech companies’ overall engagement with climate policy by analyzing activities including their top-level communications as well as lobbying on specific legislation...”

File imageUK Met Office

Climate Scientist Katharine Hayhoe’s Faithful Quest to Heal a Divided World. Here’s an excerpt of an interview at Religion & Politics: “…Though we have been very focused on the divide between the people who think that climate change is real and those who do not, we should be more concerned with the divide between those who think it’s real and those who think it matters to them. You can concede that climate change is real and important and even serious, but if you don’t think it matters to you, then you’re unlikely to do anything to fix it. I should add, too, that polling data shows we are not talking about it. We are not having conversations about climate, and the media is not covering it. I saw a pretty shocking statistic recently: that Jeff Bezos’ space launch had received as much media attention in a single day as climate change had received in the previous year. So we aren’t talking about it, and talking is a window into our minds. It’s our means for showing others what we think about, what we care about. We can’t read each other’s minds. If we, as individuals and as a nation, are not talking about climate change, then it will never receive the priority that it requires...”

Xi Announces Ending Of Chinese Coal Support Abroad: Climate Nexus has headlines and links: “China will no longer build coal-fired power plants overseas, Chinese President Xi Jinping announced Tuesday in an address to the UN General Assembly. Xi gave no timeline, the announcement is likely to mark the beginning of the end of coal plant construction in the developing world. Depending on when it is implemented, China’s new policy could cut off $50 billion of foreign investment and halt the construction of up to 47 planned coal plants in 20 countries, about equal to the entire remaining German coal fleet. “It’s a big deal. China was the only significant funder of overseas coal left. This announcement essentially ends all public support for coal globally,” Joanna Lewis, an expert on China, energy and climate at Georgetown University, told the AP. “This is the announcement many have been waiting for.” Asia Society Policy Institute fellow and former climate diplomat Thom Woodroofe described the announcement as a “line in the sand” and told the Guardian, “It is further evidence China knows the future is paved by renewables. The key question now is when they will draw a similar line in the sand at home.” (The Guardian, NPR, Wall Street Journal $, Reuters, New York Times $, Politico, Axios, BBC, Reuters, Climate Home, CNET, FT $, Washington Examiner)

Climate Change and Crops. If we continue on our current emissions path crop yields will be impacted. Here’s an excerpt from a summary at Climate Central: “…Extreme heat and drought are colliding across large swaths of the United States, damaging crops in the process. A new study shows that drought exacerbates crop damages from heat, and that drier heat waves from our warming climate may cut global corn and soybean yields by 5% globally. Corn production is expected to fall across much of the U. S., with especially strong declines in Missouri, Kansas, and the Carolinas. Because the harvest is larger in portions of Nebraska, Iowa, and Illinois, the economic impacts are potentially higher in these locations…”

Climate Change is Killing Trees and Causing Power Outages. NPR reports: “...Climate change has stoked a host of threats to trees, not just in California but across the country. Extreme storms, droughts, disease and insects are stressing and killing trees, and these trees pose a growing threat of wildfires and to grid reliability, many large utilities say. The Dixie Fire in Northern California, which has already burned more than 950,000 acres, was likely sparked by a tree falling onto a power line. According to more than a dozen of the country’s largest utilities, branches and trees falling on power lines are a leading source of power outages. Some utilities say that because of factors related to climate change, trees are dying faster than they can reach them on their normal trimming cycles...”

A woman street vendor carries water for sale in Kanda neighbourhood of Accra, Ghana, November 27, 2018.REUTERS/Zohra Bensemra

Twin Threats: Climate Migrants Said to Face Greater Risk of Modern Slavery. A story at Thomas Reuters Foundation made me do a double-take; here’s an excerpt: “…Climate change acts as a “stress multiplier” on existing factors such as poverty, inequality and conflict that drive modern slavery, with those uprooted from their homes especially at risk, the report noted. It describes situations where people affected by climate change impacts – particularly women and girls – find themselves prey to trafficking agents or working merely to pay off escalating debts to employers. That might include people living in aid camps because their homes were destroyed in a storm, or female family members left behind at home after their male relatives migrate to cities in search of work as the family land becomes infertile. For example, in the wake of Typhoon Haiyan in the Philippines, in 2013, many survivors were coerced into working as prostitutes or labourers, the report noted. Costly and damaging annual floods in Assam, in north-east India, also have led to women and girls being forced into child slavery or forced marriage to make ends meet...”

Climate Change: World Now Sees Twice as Many Days Over 50C. BBC News has results of new research: “The number of extremely hot days every year when the temperature reaches 50C has doubled since the 1980s, a global BBC analysis has found. They also now happen in more areas of the world than before, presenting unprecedented challenges to human health and to how we live. The total number of days above 50C (122F) has increased in each decade since 1980. On average, between 1980 and 2009, temperatures passed 50C about 14 days a year. The number rose to 26 days a year between 2010 and 2019. In the same period, temperatures of 45C and above occurred on average an extra two weeks a year...”

Why We’re Experiencing So Many Hot Summer Nights. Dew points are consistently higher, there is more water in the air than a generation ago, which limits how much temperatures can cool at night. Here’s a clip from The New York Times (paywall): “…While average nighttime temperatures are on the rise, it’s the extremes — that is, the number of abnormally hot nights — that are rising the fastest. A small shift in the average can mean a large change in the frequency of extreme events, with big consequences for climate change. When the average temperature increases, the distribution of daily temperatures shifts towards its tail end. “We are making that tail fatter,” said Claudia Tebaldi, a climate scientist at the Pacific Northwest National Laboratory. “And so the possibility of experiencing a day that belongs to the tail is higher than it used to be.” There’s a saying among climate scientists: “The sting is in the tail.” Extreme weather, although rare, does the most damage...”

Why Do Leaves Change Colors in the Fall? Using Satellite-Based Wind Lidar to Improve Hurricane Forecasts

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