donsutherland1

From the Yale Climate Connections blog: Like a modern-day Ebenezer Scrooge escorted by the Ghost of Summers Yet to Come, California is catching a glimpse of its future summer weather. The view is a hellish one. Within a two-week span in August, California saw: – the “fire tornado” just north of Lake Tahoe – 130 degrees Fahrenheit heat in Death Valley, which may be the hottest temperature ever reliably recorded on Earth – a largely dry thunderstorm with 11,000 lightning strikes across California over 72 hours, igniting more than 300 wildfires, including two of the three largest ever recorded in the state (and still growing), creating the worst air quality in the world – one million acres burned in California in 2020 with 4 months to go in fire season – tens of thousands of people evacuated from their homes as the fires drew near – rolling power blackouts during a record heat wave – gray, unhealthy air. A blood red sun. Flakes falling from the sky, coating everything below in a layer of white… not snow, but ash. These ghastly scenes all bear links to climate change, and as a result, climate scientists expect them to occur more frequently in the future as global warming continues to raise temperatures and dry the landscape. https://yaleclimateconnections.org/2020/08/climate-change-is-worsening-californias-hellish-wildfires/

Morning thoughts... Today will be mostly sunny and pleasant. Temperatures will likely reach the lower 80s across much of the region. Likely high temperatures around the region include: New York City (Central Park): 81° Newark: 83° Philadelphia: 84° Somewhat warmer than normal conditions will likely prevail through much of next week. Today will be the last day of the historic heat in parts of the Southwest. Record cold is likely tomorrow in the Rockies, along with accumulating snow.

In its coverage of the extreme heat, the Los Angeles Times had a fairly lengthy discussion of climate change. https://www.latimes.com/california/story/2020-09-05/heat-health-risks This linkage to climate change provides important context for the newspaper’s readers and the general public. The Washington Post also provide climate change-related context when discussing California’s fires and extreme heat. The New York Times did not, depriving its readers of important insight into the events.

California’s biggest wildfires:

2020 was the 11th summer on record with a mean temperature above 94.5 degrees in Phoenix. It also became the 6th out of those 11 summers to see the 9/1-6 period wind up warmer than the entire summer average. All of those six summers with a warmer start to September occurred 2000 or later and four occurred 2010 or later. What this means is that the intense heat of exceptionally warm summers now has a tendency to last a little longer than had been the case in the past.

Temperatures rose into the lower 80s across much of the region today. A similar day is in store for tomorrow. Overall, the first half of September will likely wind up somewhat warmer than normal. The probability of the arrival of an autumn-like air mass after mid-month has increased. The historic September heat wave of 2020 brought more searing temperatures to the Southwest. The extreme heat will break will break after tomorrow. Select high temperatures included: Blythe, CA: 118° (old record: 114°, 1955) Burbank, CA: 114° (old record: 111°, 1955) ***Tied September and all-time record*** Death Valley, CA: 123° (old record: 118°, 1955 and 2006) Denver: 97° (tied record set in 2013) El Centro, CA: 118° (old record: 114°, 1934) Flagstaff: 91° (old record: 87°, 1977) Kingman, AZ: 110° (old record: 104°, 1930, 1932 and 1955) ***New September record*** Lake Havasu City, AZ: 118° (old record: 113°, 1977, 1986 and 2012) ***Tied September record*** Las Vegas: 114° (old record: 110°, 1955) ***New September record*** Needles, CA: 120° (old record: 114°, 1924) ***Tied September record*** Palm Springs, CA: 120° (old record: 114°, 1923, 1957 and 1986) Phoenix: 113° (old record: 111°, 1986 and 2013) Pueblo, CO: 103° (old record: 100°, 1933) ***New September record*** Reno: 95° Tucson: 107° (old record: 106°, 1952) Yuma, AZ: 115° (old record: 113°, 1986) Death Valley recorded its 3rd consecutive day with high temperatures of 120° or above. That ties the September record, which was set during September 1-3, 1950 and tied during September 2-4, 2007. In addition, it ties the record for the most such days in September, which was set in 1950 and 2007. Palm Springs recorded its second consecutive day with a high temperature of 120° or above for the first time on record in September. Phoenix recorded its 3rd consecutive day with a high temperature of 113° or above. That is the longest such stretch in September. Following the historic heat, record cold will plunge into the Rockies late Monday and Monday night. As the temperature plunges, Denver could pick up only its fourth measurable snowfall on record prior to September 15. Recordkeeping began in 1872. The prior events were: September 3, 1961: 4.2" September 8, 1962: 0.7" September 13, 1993: 5.4" In addition, Denver could see its earliest temperature below 30° during the coming cold shot. The current record is September 14, 2003 when the temperature fell to 29°. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +12.18. Today, the preliminary Arctic Oscillation (AO) figure was +0.514. On September 5, the MJO was in Phase 4 at an amplitude of 0.819 (RMM). The September 4-adjusted amplitude was 1.015. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Finally,on September 5, Arctic sea ice extent data was not available. On September 2, Arctic sea ice extent was 3.861 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

It’s not hubris. It’s a conclusion based on the evidence. Here’s one study that shows historical temperature trends, the trends that would have occurred only with natural forcings, and those that would have occurred only with anthropogenic forcings. The relevant charts are on page 8 of the paper. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/jgrd.50239

When greenhouse gases are omitted, the observed ongoing warming cannot be replicated. Only when such gases are included can the observed warming be replicated. Gavin Schmidt, director of National Aeronautics and Space Administration’s Goddard Institute for Space Studies, said that scientists look at a lot of different things at once. “We have a very, very clear understanding that the amount of heat in the ocean is increasing—the ocean heat content is going up by a lot,” said Schmidt. “That implies that there must be an external change in the radiation budget of the earth—more energy has to be going in than leaving... To understand this rapid change in climate, scientists look at data sets and climate models to try to reproduce the changes that have already been observed. When scientists input only natural phenomena such as the sun’s intensity, changes in the Earth’s orbit and ocean circulation, the models cannot reproduce the changes that have occurred so far. “We have independent evidence that says when you put in greenhouse gases, you get the changes that we see,” said Schmidt. “If you don’t put in greenhouse gases, you don’t. And if you put in all the other things people think about—the changes in the earth’s orbit, the ocean circulation changes, El Niño, land use changes, air pollution, smog, ozone depletion—all of those things, none of them actually produce the changes that we see in multiple data sets across multiple areas of the system, all of which have been independently replicated.” In other words, only when the emissions from human activity are included, are the models and data sets able to accurately reproduce the warming in the ocean and the atmosphere that is occurring. https://blogs.ei.columbia.edu/2017/04/04/how-we-know-climate-change-is-not-natural/

In its coverage of the ongoing severe wildfires in California, The Washington Post provided a linkage to climate change: The article noted: Studies show human-caused climate change is tilting the odds in favor of more frequent, severe and longer lasting heat waves, as well as larger wildfires throughout large parts of the West. Research published last month, for example, shows climate change is tied to more frequent occurrences of extreme-fire-risk days in parts of California during the fall (meteorologists define the fall as beginning on Sept. 1). https://www.washingtonpost.com/weather/2020/09/06/california-wildfires-heat-wave/

There is literature about the lags namely where increasing solar insolation kicked off warming in the Northern Hemisphere and subsequent warming led to increases in CO2, which, in turn, amplified further warming. That humanity has engineered a “short cut” of sorts by dramatically and rapidly increasing atmospheric CO2 does not mean that (1) this increased CO2 won’t drive warming (CO2's properties found in physics and other empirical literature suggests that it should; the ongoing observed warming demonstrates that the expected warming is taking place) and (2) that one assumes the climate system is linear. No serious climate scientist has made such claims that I can find. The real question is why atmospheric CO2 levels consistent with the Pliocene should not produce warming perhaps of a similar magnitude? Global temperature are rising. The 2010s was the warmest decade of the instrument record (all major data sets). The 2020s will likely exceed that level of warmth.

A basic primer in slides by Paleoclimatologist Jessica Tierney: https://www.agci.org/sites/default/files/pdfs/lib/main/19s1_05_08_1800_Tierney_WOR_Aspen2019.pdf Dr. Tierney has done extensive research on earlier climate regimes e.g., the Eocene warming. She is the co-author of newly published paper on temperatures during the last ice age.

Also, there on September 4, Israel and Cyprus set national record high temperatures for September. Jerusalem reached 109.

Morning thoughts... Today will be mostly sunny and pleasant. Temperatures will likely reach the lower 80s across much of the region. Likely high temperatures around the region include: New York City (Central Park): 81° Newark: 83° Philadelphia: 83° Somewhat warmer than normal conditions will likely prevail through much of next week. The historic September heat will continue in the Southwest. Death Valley, which reached 125° yesterday, could approach or even exceed that mark today.

Denver has had one case where there was measurable snow the day after the temperature hit 90 degrees. On September 12, 1993, the temperature reached 92 degrees. On September 13, 5.4” snow fell.

Tomorrow will see sunshine and readings generally in the lower 80s across the region. Overall, the first half of September will likely wind up somewhat warmer than normal. The probability of the arrival of an autumn-like air mass after mid-month has increased. The historic September heat wave of 2020 scorched the Southwest for another day. Select high temperatures included: Casper: 98° (old record: 95°, 1978) ***Tied September Record*** Cheyenne: 94° (old record: 92°, 1998 and 2019) Death Valley, CA: 125° (old record: 120°, 1955) ***New September Record*** Denver: 101° (old record: 98°, 2019) ***New September Record*** El Centro, CA: 121° (old record: 114°, 1934 and 1945) ***New September Record*** Flagstaff: 90° (old record: 89°, 1945) Kingman, AZ: 109° (old record: 104°, 1908) ***New September Record*** Lake Havasu City, AZ: 117° (old record: 115°, 2011) Las Vegas: 112° (old record: 109°, 1947, 1955 and 1977) Needles, CA: 119° (old record: 114°, 1891 and 1923) Palm Springs, CA: 122° (old record: 116°, 1955) ***New September Record*** Phoenix: 115° (old record: 113°, 1945) Pueblo, CO: 100° Reno: 100° (old record: 99°, 2017) Tucson: 108° (old record: 107°, 1945) Yuma, AZ: 120° (old record: 115°, 1945) Death Valley reached 125°. That broke the September record of 123°, which was set on September 2, 1996. El Centro, CA reached 121°. That surpassed both the existing August and September records. The previous latest 120° or above reading on record there occurred on July 28, 1995 when the temperature reached 121°. Since 1925, there have been just 10 days on which the temperature reached 120° or above at El Centro. Seven occurred since 2000 and six occurred since 2010. Phoenix reached at least 115° for the 14th time this year. The previous annual record for 115° or warmer was 7 days in 1974. Separately, Miami reached 93°, which tied the daily record set in 1996 and tied in 2017 and 2019. Today was Miami's 49th day where the temperature reached 93° or above. The previous record was 44 days, which was set just last year. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +8.56. Today, the preliminary Arctic Oscillation (AO) figure was -0.045. On September 4, the MJO was in Phase 3 at an amplitude of 1.015 (RMM). The September 3-adjusted amplitude was 1.018. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Finally,on September 4, Arctic sea ice extent data was not available. On September 2, Arctic sea ice extent was 3.861 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

Two papers: https://iopscience.iop.org/article/10.1088/1748-9326/10/1/014005 https://www.nature.com/articles/s41467-018-05256-8.epdf

Morning thoughts... Today will be mostly sunny and cooler than yesterday. Temperatures will likely reach the upper 70s and lower 80s across the region. Likely high temperatures around the region include: New York City (Central Park): 79° Newark: 81° Philadelphia: 81° A deep trough will continue to move into the Northern Plains in coming days. However, the cold will likely remain west of the Appalachians through at least much of next week. Extreme heat will again scorch the Southwest. Numerous cities will approach or set daily record temperatures with some September records approached or broken. Death Valley could see the temperature top out near or just above its monthly record of 123°.

The latest Needles hit 120 was September 1, 1950.

There is some research indicating that Arctic Amplification also has an impact on the summer weather pattern in addition to that of the fall. In general, one line of thought is that it is leading to greater persistence of events due to a wavier and slowing jet stream.

Actually, the UAH has had documented issues. RSS, RATPAC, etc., are better tools. That UAH is an outlier highlights its issues. One paper: https://journals.ametsoc.org/jtech/article/34/1/225/342433

It’s tough to know. But some of the studies suggest that New York City will have a climate similar to Virginia Beach by 2050.

Cooler air will return starting tomorrow as a deep trough moves from Canada toward the Great Lakes Region and into the Northern Plains. The coldest air associated with this trough will likely remain mainly west of the Appalachians. That trough may persist until near or just after mid-month. Nevertheless, the first half of September will likely wind up somewhat warmer than normal. Another bout of extreme heat commenced in the Southwest in spectacular fashion in which two monthly records were toppled. Select high temperatures included: Blythe, CA: 115° (tied record set in 1948) Death Valley: 122° (old record: 121°, 2007) Denver: 91° Flagstaff: 90° (tied record set in 1945) Kingman, AZ: 107° (old record: 104°, 2019) Lake Havasu City: 115° (old record: 114°, 1993, 1995 and 2007) Las Vegas: 109° Needles, CA: 117° (old record: 116°, 2019) Palm Springs, CA: 116° (tied record set in 1955) Phoenix: 114° (old record: 112°, 1945 and 2019) Reno: 102° (old record: 100°, 1988 and 2017) ***New September Record*** Tucson: 110° (old record: 106°, 1945 and 2011) ***New September Record*** Yuma, AZ: 114° Until today, Tucson's latest season 110° or above temperature occurred on August 22, 1930 when the temperature also topped out at 110°. September 2020 became the 4th consecutive September during which the temperature reached 120° or above. Prior to the current stretch, the record was two consecutive years. The temperature was also the hottest September temperature since September 2, 2017 when the mercury also reached 122°. Only September 2, 1996 with a high temperature of 123° was hotter in September. That record could be challenged tomorrow and Sunday. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was -0.7°C for the week centered around August 26. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.02°C and the ENSO Region 3.4 anomaly has averaged -0.63°C. Neutral-cool conditions will likely evolve into La Niña conditions during the fall. The SOI was +6.78. Today, the preliminary Arctic Oscillation (AO) figure was -0.198. On September 3, the MJO was in Phase 3 at an amplitude of 1.018 (RMM). The September 2-adjusted amplitude was 1.063. Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September. Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. Finally, on September 3, Arctic sea ice extent data was not available. On September 2, Arctic sea ice extent was 3.861 million square kilometers (JAXA). Based on the August 31 figure, minimum Arctic sea ice extent will most likely finish somewhere from 3.645 million to 3.695 million square kilometers in September. The highest 25% bound is 3.742 million square kilometers. The lowest 25% bound is 3.581 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

Some numbers for Denver: 27 cases where measurable snow fell a day after the temperature hit 80 degrees or above. Highest temperature preceding a measurable snow event: 92 degrees, September 12, 1993 (5.4" snow fell on September 13) Most recent case: October 9, 2019: 83 degrees (1.0" fell on October 10)

Morning thoughts... Today will be mainly sunny and quite warm. Temperatures will likely reach the middle and upper 80s across the region. Likely high temperatures around the region include: New York City (Central Park): 85° Newark: 87° Philadelphia: 86° Cooler air will return for the weekend as a deep trough will move from Canada toward the Great Lakes Region and into the Northern Plains. Another round of dangerous heat will develop in the Southwest today. Parts of Arizona, California, Colorado, and Nevada could see several days of near record to record high temperatures. Following the heat, parts of Colorado and Wyoming, including Denver, could see their first snowfall of the season next week.

Back last year, Eric Blake of the National Hurricane Center tweeted about Miami’s record 42nd day with a high temperature of 93 degrees or above. 2019 went on to finish with 44. Through September 4, 2020 has had 48 such days. 2019 also went on to record an annual mean temperature of 79.1 degrees, which tied 2017 for the second warmest year on record 2015, with an annual mean temperature of 79.2 degrees, is Miami’s warmest year on record.