Saturday September 26th… Dear Diary. The main purpose of this ongoing blog will be to track United States extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉
Main Topic: Western Heatwave “Desdemona” Begins
Dear Diary. The well advertised by meteorological models and dreaded western heatwave, which I’ve dubbed “Desdemona,” has begun across portions of the Weet this weekend:
I could make a good case for Desdemona beginning on Friday:
Maxes from the mid 90s to the low 100s don’t look so dire on the above chart, but combined with National Weather Service advisories a clearer picture comes into focus:

The worst hazard area is in northern California where many communities face the prospect of deadly fires going into early next week. The state has been suffering from wildfire threats for many years now, and Desdemona is just the latest spate of weather elevating fire risk.
For another perspective on this latest round of heat and easterly flow winds, which will combine to produce the fire threat, here is a new Guardian article:

Firefighters position themselves on a ridge overlooking flames from the Bobcat Fire in a valley below in the Angeles national forest on Wednesday. Photograph: Frederic J Brown/AFP/Getty Images
California braces for dangerous heat as wildfire battle continues
Triple-digit temperatures could spark new fires just a few weeks after a record heatwave
California is bracing for another dangerously warm weekend, with dry winds, parched vegetation, and triple-digit temperatures threatening to ignite new fires and complicating containment efforts in an embattled state.
With only a few weeks’ reprieve after a record heatwave in early September, firefighters have made progress in containing the dozens of blazes tearing across the region. But fatigued crews – many of whom have spent weeks fighting on the frontline – are preparing for a potentially rough week ahead.
Red flag warnings have been issued across northern California from Saturday through Monday. “Even if you live on the coast or in the city, you’re going to feel the heat Monday,” Drew Tuma, a local ABC meteorologist, said. “I expect some places to hit 106F, 107F Monday – easily.”
Heat isn’t the only concern. Gusty winds and low humidity are expected to elevate extreme fire dangers into early October, especially as swaths of the state experience “severe drought”, according to analysts with the US Department of Agriculture.
In northern and central areas, the strongest winds were forecast to occur from Saturday night into Sunday morning, followed by another burst Sunday night into Monday. In southern California, meteorologists anticipate very hot and dry weather conditions with weak to locally moderate Santa Ana winds on Monday.
The Pacific Gas & Electric utility warned it may have to shut off power to areas where gusts of wind could damage its equipment or hurl debris into lines that could ignite flammable vegetation. The utility posted a power cut “watch alert” for Saturday evening through Monday morning for about 21,000 customers in portions of northern Butte, Plumas and Yuba counties.
The heat isn’t just weather – it’s part of a trend. Nasa researchers who document the rising temperatures report that the fires and the conditions that cause them are going to get worse.
“Heatwaves are becoming more frequent, lasting longer, and increasing in night-time temperature and humidity, particularly in urban regions such as the Los Angeles basin,” reported Glynn Hulley, a climate scientist at Nasa’s Jet Propulsion Laboratory who co-authored a study this year on increasingly intense heatwaves. Los Angeles recorded its highest temperature ever – 121F – in early September.
Hulley and his team raised concerns about a troubling upward trend in night-time temperatures. An overnight reprieve of cool air can help curb some of the impact of heat, giving firefighters the chance to contain big burns and vulnerable populations the ability to recover.
“The heatwaves that end up killing a lot of people are really warm, humid nighttime heatwaves, and they are going to become more common,” added Brian Kahn, a co-author on the study and researcher at the laboratory. “Night-time is normally your chance to cool off, but now there’s less relief from the heatwave.”
California is already fighting dozens of wildfires, with more than 17,400 firefighters on the ground. Though the state is still in the early part of a fire season that could last through the end of the year, flames have already consumed a record 3.6m acres. Roughly 6,900 structures have been destroyed and 26 people have lost their lives, officials report, since 15 August.
“[Firefighters] are making good progress on the majority of our fires that are still burning,” said Lynne Tolmachoff of Cal Fire, the state’s firefighting agency. “But of course, we do have to be very cognizant that we are expecting a big heat-up. It could potentially spread a fire that’s already been burning or any new starts that happen can grow and spread rapidly.”
Tolmachoff said the state was ready and had resources to devote to new fires if they erupted. Incident management teams had been called back from the front lines and were standby. “We have brought in resources from out of state to help relieve firefighters in state, to get them off duty,” she says. “We want to give them a little bit of a break and get them ready to go again for another round, should it happen.”
The agency has been fully deployed for weeks, and firefighters across the state have been serving long deployments. First responders said in recent weeks that crews were stretched thin and the unprecedented fire season had already taken a toll.
“I know people are being pushed to limits,” Vince Wells, a former fire chief who served Contra Costa county, said last week. “We are dealing with the heat, on top of a pandemic, on top of the large number of fires and the shortness of resources.”
He and others highlighted that firefighters were also facing new challenges as wildfires crept out of the wilderness and into communities. California’s largest wildfire is threatening a marijuana-growing enclave, and authorities said many local residents had refused to evacuate and abandon their maturing crops even as weather forecasters predicted more hot, dry and windy conditions that could fan flames.
The August Complex fire is nearing the small communities of Post Mountain and Trinity Pines, about 200 miles (322km) north-west of Sacramento, the Los Angeles Times reported.
Mike McMillan, spokesman for the federal incident command team managing the northern section of the August Complex, said fire officials planned to deliver a clear message that “we are not going to die to save people. That is not our job.”
“We are going to knock door to door and tell them once again,” McMillan said. “However, if they choose to stay and if the fire situation becomes, as we say, very dynamic and very dangerous, we are not going to risk our lives.”
The day after the election …
… the US withdraws from the Paris climate accord, on 4 November. Five years ago nearly 200 countries committed to a collective global response to tackle the climate crisis. But when Donald Trump took office he announced that the US would leave the Paris agreement. On the one issue that demands a worldwide response to help safeguard the Earth for future generations, the US has chosen to walk away. The president is playing politics with the climate crisis – the most defining issue of our time.
The stakes could scarcely be higher and with your help we can put this issue at the center of our 2020 election coverage. The election will be a referendum on the future of democracy, racial justice, the supreme court and so much more. But hovering over all of these is whether the US will play its role in helping take collective responsibility for the future of the planet.
The period since the Paris agreement was signed has seen the five hottest years on record. If carbon emissions continue substantial climate change is unavoidable. The most impacted communities will also be the most vulnerable. Instead of helping lead this discussion the White House prefers to roll back environmental protections to placate the fossil fuel industry.
High-quality journalism that is grounded in science will be critical for raising awareness of these dangers and driving change. You’ve read more than 26 articles in the last year. Because we believe every one of us deserves equal access to fact-based news and analysis, we’ve decided to keep Guardian journalism free for all readers, regardless of where they live or what they can afford to pay. This is made possible thanks to the support we receive from readers across America in all 50 states. If you can, support the Guardian from as little as $1 – and it only takes a minute. Thank you. Support The Guardian

Desdemona will not be as hot as the early September western heatwave named “Chort.” The episode will last all of next week, but at least our jet stream leading to record heat will not be as amplified by next weekend:

(Compared with the zenith of the thing forecast on Tuesday)

Here is an “ET” from overseas:
Here is more climate and weather news from Saturday:
(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)
Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:
(If you like these posts and my work please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support.)
Guy Walton “The Climate Guy”