bluewave

We are on track to set a new September monthly 500 mb positive height record for the West Coast. A new daily record was set earlier this month. This would surpass the previous September monthly record set in 2012.

https://www.disl.edu/about/news/marine-heatwaves-and-hurricanes-study-examines-compounding-impact-of-severe-weather Several coastal communities are picking up the pieces after being ravaged by hurricanes in the past month. Hurricane Laura, a category 4, and Hurricane Sally, a category 2, seemed to meander their way across the Gulf of Mexico constantly shifting forecasts and keeping meteorologists on their toes. In the hours before these storms struck land, they seemed to explode in intensity. Researchers at the Dauphin Island Sea Lab with support from the Jet Propulsion Laboratory can offer insight into why these storms intensified quickly as they moved across the continental shelf. “Surprisingly, both Hurricane Laura and Hurricane Sally appeared to have similar setups to Hurricane Michael with both storm events being preceded by smaller storms (i.e. Hurricane Hanna and Marco, respectively),” Dr. Brian Dzwonkowski explained. “This pre-storm setup of the oceanic environment likely contributed to the intensification prior to landfall. Importantly, this pre-landfall intensification was not well predicted by hurricane models or forecasts, which as you can imagine is critical information for evacuation and disaster preparation.” Dzwonkowski and his team’s publication, “Compounding impact of severe weather events fuels marine heatwave in the coastal ocean”, outlines how one storm could impact the intensity of another storm by restructuring the thermal properties of the water column. Nature Communications published the findings in its September issue. The research focuses on Hurricane Michael which devastated Mexico Beach, Florida, and the surrounding communities, on October 10, 2018. The category 5 storm intensified hours before making landfall. Dzwonkowski, a physical oceanographer with the Dauphin Island Sea Lab and Associate Professor at the University of South Alabama in the Department of Marine Sciences, and his team tracked down the key events and processes that pushed the coastal waters in the Gulf of Mexico to an extremely warm state (i.e. a marine heatwave), likely contributing to the intensification of a storm so close to shore. Unlike the deep ocean, the continental shelf has a shallow bottom that limits how much cold water can be mixed up to the surface, cooling the sea surface temperature and weakening approaching storms. Dzwonkowski and his team focused on how a strong mixing event pushes surface heat downward and clears the bottom water of its cold water reserve. If this mixing is followed by a period of rewarming, such as an atmospheric heatwave, the shelf’s oceanic environment could be primed for the potential generation of extreme storm events, i.e. Hurricane Michael. This work shows that understanding the preceding weather conditions in a region where a storm is going to make landfall can improve interpretation of hurricane model forecasts and what the storm is likely to do prior to landfall,” says Dr. Dzwonkowski In mapping out heat flux and mixing, the team focused on the Mississippi Bight in late summer and early fall with data gathered by a mooring site off Dauphin Island’s coastline. The mooring site collects data throughout the water column allowing for the full heat content of the shelf to be determined. The period prior to the landfall of Hurricane Michael turned out to be the warmest ocean conditions during this time period in the 13-year record. “Turns out hurricanes and atmospheric heatwaves will be getting stronger in a warming world which would indicate the identified sequence of events that generate these extreme conditions may become more frequent,” Dzwonkowski said. “The occurrence of extreme heat content events, like marine heatwaves has significant implications for a broad range of scientific management interests beyond hurricane intensity.”Importantly, the mechanisms that generated this marine heatwave are expected to be more frequent and intense in the future due to climate change, increasing the likelihood of such extreme conditions. For example, coral reefs and hypoxia-prone shelves are already stressed by long-term warming trends. These temperature-specific benthic communities and habitats are typically of significant societal and economic value. As such, the newly identified sequence of compounding processes is expected to impact a range of coastal interests and should be considered in management and disaster response decisions. This research was funded by the NOAA RESTORE Science Program and NOAA NGI NMFS Regional Collaboration network. https://www.nature.com/articles/s41467-020-18339-2 Abstract Exposure to extreme events is a major concern in coastal regions where growing human populations and stressed natural ecosystems are at significant risk to such phenomena. However, the complex sequence of processes that transform an event from notable to extreme can be challenging to identify and hence, limit forecast abilities. Here, we show an extreme heat content event (i.e., a marine heatwave) in coastal waters of the northern Gulf of Mexico resulted from compounding effects of a tropical storm followed by an atmospheric heatwave. This newly identified process of generating extreme ocean temperatures occurred prior to landfall of Hurricane Michael during October of 2018 and, as critical contributor to storm intensity, likely contributed to the subsequent extreme hurricane. This pattern of compounding processes will also exacerbate other environmental problems in temperature-sensitive ecosystems (e.g., coral bleaching, hypoxia) and is expected to have expanding impacts under global warming predictions.

Montana was one of the few spots not to see as many above normal months.

Yeah, I saw that. The early 90s were colder times combined with the strong +AO and PV. We actually surpassed those records last JFM. A new paper mentions that the IO standing wave may have contributed. Similar to another paper that I posted last winter. So we need to look to the Indian Ocean for hints on the AO. So some of the long range +AO forecasts for last winter worked out very well. But it verified much stronger than they indicated. https://www.essoar.org/pdfjs/10.1002/essoar.10503356.1 P Positive SST anomalies in the Indian Ocean have

Maybe another 70° minimum if the front slows down enough.

Looks to max out from 4 to 5 sd around Alaska and also Greenland.

Expansion of the extreme drought conditions in New England.

The most recent paper contains errors just like the 2013 stadium wave one which predicted that the hiatus would last into the 2030s.

The 1981-2010 September mean in NYC is 68.0. But we have been averaging closer to 70 since 2010. So close to average feels cool. Sep 81-10 NCDC official 75.2 60.8 68.0 Monthly Mean Avg Temperature for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Year Sep Season Mean 70.5 70.5 2019 70.4 70.4 2018 70.7 70.7 2017 70.5 70.5 2016 71.8 71.8 2015 74.5 74.5 2014 69.7 69.7 2013 67.9 67.9 2012 68.8 68.8 2011 70.0 70.0 2010 71.1 71.1

Why are you citing Curry after her global temperature projection in 2013 was shown to be unrealistically low? https://news.gatech.edu/2013/10/10/‘stadium-waves’-could-explain-lull-global-warming The stadium wave signal predicts that the current pause in global warming could extend into the 2030s," said Wyatt, an independent scientist after having earned her Ph.D. from the University of Colorado in 2012. Curry added, "This prediction is in contrast to the recently released IPCC AR5 Report that projects an imminent resumption of the warming, likely to be in the range of a 0.3 to 0.7 degree Celsius rise in global mean surface temperature from 2016 to 2035." Curry is the chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.

Katharine Hayhoe September 4, 2017 · Is there such a strong consensus in the scientific community on climate change simply because anyone proposing alternate explanations is black-balled and suppressed? This is one of the most frequent questions I get here on Facebook. It's a lot easier for someone to claim they've been suppressed than to admit that maybe they can't find the scientific evidence to support their political ideology that requires them to reject climate solutions and, to be consistent, 150 years of solid, peer-reviewed science, too. But over the last 10 years, at least 38 papers were published in peer-reviewed journals, each claiming various reasons why climate wasn't changing, or if it was, it wasn't humans, or it wasn't bad. They weren't suppressed. They're out there, where anyone can find them. So we took those papers and - thanks to the superhuman efforts of my colleague Rasmus Benestad - recalculated all their analyses. From scratch. And you know what we found? Every single one of those analyses had an error - in their assumptions, methodology, or analysis - that, when corrected, brought their results into line with the scientific consensus. It's real, it's us, it's serious. Learning from mistakes in climate research https://link.springer.com/article/10.1007/s00704-015-1597-5

Warmest melt season resulted in the second lowest minimum sea ice extent and a new record low in the Central Arctic.

The record Western Ridge just won’t let up.

This was the 10th coldest 9-16 to 9-22 in NYC. It was also the coldest since 1993. Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Mean Avg Temperature Sep 16 to Sep 22 Missing Count 1 1875-09-22 54.7 0 2 1871-09-22 55.8 0 3 1990-09-22 59.5 0 4 1929-09-22 59.6 0 5 1956-09-22 59.7 0 6 1993-09-22 59.8 0 7 1962-09-22 60.3 0 8 1879-09-22 60.4 0 9 1873-09-22 60.7 0 10 2020-09-22 60.9 0

These were my favorite seasons for snowstorm quality.... 17-18 15-16 10-11 02-03 95-96 82-83 81-82 77-78

I wonder if the EPS weeklies will be included with the free Euro maps in October?

One of my all-time favorites in Jan 2016 also. 10-11 could have surpassed 95-96 in spots had it continued another 30-45 days. 10-11 had snowstorm quality and extended snow cover. Maximum 33-Day Total Snowfall for NEWARK LIBERTY INTL AP, NJ Click column heading to sort ascending, click again to sort descending. Rank Value Ending Date Missing Days 1 61.5 2011-01-27 0 2 53.6 2011-01-26 0 3 48.7 1978-02-14 0 4 45.7 1978-02-18 0 5 45.5 1961-02-16 0

Yeah, the continuous -EPO/+PNA was great if you liked cold and extended snow cover in 13-14 and 14-15. But the lack of -NAO left much to be desired in the KU extreme snowfall department. I will take individual snowstorm quality every time over extended snow cover and cold. Even if it means +13 in December or 80° in February.

The winter weather swings in recent years have been remarkable. With the exception of 10-11, all my recent favorite snowstorms have occurred during winters with some extreme warmth. 15-16...16-17...17-18....etc...I missed the best jackpots during the colder 13-14 and 14-15 winters.

That was the one. Record blizzard in January...first February 80°...30” of snow in March on Long Island. So the big winter weather swings which have been occurring more frequently in recent years. https://mashable.com/2018/01/04/bomb-cyclone-costal-flooding-boston/

Probably the best looking system in that region since the 950mb benchmark blizzard.

The record Western Ridge is our latest stuck weather pattern.

NYC just extended it to 4 days with the low of 49° so far today. The streak came several days earlier than 2000. 9-19....50° 9-20....50° 9-21....49° 9-22....49° 2000-09-26 54 50 52.0 -12.1 13 0 0.33 0.0 0 2000-09-27 68 47 57.5 -6.2 7 0 0.00 0.0 0 2000-09-28 67 49 58.0 -5.3 7 0 0.00 0.0 0 2000-09-29 59 43 51.0 -11.9 14 0 0.00 0.0 0 2000-09-30 65 48 56.5 -6.0 8 0 0.00 0.0 0

https://blogs.ei.columbia.edu/2019/07/30/co2-drives-global-warming/ Earth absorbs energy from sunlight, but as the surface warms, it also emits energy in the form of infrared radiation (which we know of as heat) out into space. Water vapor and CO2, however, act like a cap, making it more difficult for Earth to get rid of this energy. Without gases like these to absorb the energy, our planet’s average surface temperature would have been near zero degrees Fahrenheit. About 99 percent of the atmosphere is made of oxygen and nitrogen, which cannot absorb the infrared radiation the Earth emits. Of the remaining 1 percent, the main molecules that can absorb infrared radiation are CO2 and water vapor, because their atoms are able to vibrate in just the right way to absorb the energy that the Earth gives off. After these gases absorb the energy, they emit half of it back to Earth and half of it into space, trapping some of the heat within the atmosphere. This trapping of heat is what we call the greenhouse effect. Because of the greenhouse effect created by these trace gases, the average temperature of the Earth is around 15˚C, or 59˚F, which allows for life to exist. CO2 makes up only about 0.04% of the atmosphere, and water vapor can vary from 0 to 4%. But while water vapor is the dominant greenhouse gas in our atmosphere, it has “windows” that allow some of the infrared energy to escape without being absorbed. In addition, water vapor is concentrated lower in the atmosphere, whereas CO2 mixes well all the way to about 50 kilometers up. The higher the greenhouse gas, the more effective it is at trapping heat from the Earth’s surface. The burning of fossil fuels affects the concentration of CO2 in the atmosphere. Before the industrial revolution, the amount of CO2 in the atmosphere was about 288 ppm. We have now reached about 414 ppm, so we are on the way to doubling the amount of CO2 in the atmosphere by the end of this century. Scientists say that if CO2 doubles, it could raise the average global temperature of the Earth between two and five degrees Celsius. We are already increasing the amount of energy that bounces back to the Earth. Because of the greenhouse effect, this is causing global warming with its many destructive impacts. Both water vapor and CO2 are responsible for global warming, and once we increase the CO2 in the atmosphere, the oceans warm up, which inevitably triggers an increase in water vapor. But while we have no way to control water vapor, we can control CO2. And because we are increasing the amount of CO2 in the atmosphere by continuing to burn fossil fuels, even in relatively small amounts compared to the entire mass of the atmosphere, we are disturbing the entire heat balance of the planet.

Even 50-year-old climate models correctly predicted global warming https://www.sciencemag.org/news/2019/12/even-50-year-old-climate-models-correctly-predicted-global-warming By Warren CornwallDec. 4, 2019 , 12:00 PM Climate change doubters have a favorite target: climate models. They claim that computer simulations conducted decades ago didn’t accurately predict current warming, so the public should be wary of the predictive power of newer models. Now, the most sweeping evaluation of these older models—some half a century old—shows most of them were indeed accurate. “How much warming we are having today is pretty much right on where models have predicted,” says the study’s lead author, Zeke Hausfather, a graduate student at the University of California, Berkeley. Climate scientists first began to use computers to predict future global temperatures in the early 1970s. That’s when newfound computing power coincided with a growing realization that rising carbon dioxide levels could boost global temperatures. As the issue gained public attention, critics questioned the reliability of rudimentary model predictions. Even a 1989 news article in Science radiated skepticism, stating that “climatologists may have a gut feeling that the greenhouse effect is heating up Today, the models are much more sophisticated. Mainframe computers driven by paper punch cards have given way to supercomputers running trillions of calculations in 1 second. Modern models account for myriad interactions, including ice and snow, changes in forest coverage, and cloud formation—things that early modelers could only dream of doing. But Hausfather and his colleagues still wanted to see how accurate those bygone models really were. The researchers compared annual average surface temperatures across the globe to the surface temperatures predicted in 17 forecasts. Those predictions were drawn from 14 separate computer models released between 1970 and 2001. In some cases, the studies and their computer codes were so old that the team had to extract data published in papers, using special software to gauge the exact numbers represented by points on a printed graph. Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9°C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters. Global temperatures have risen approximately 0.9°C since 1970, though some areas have warmed much more than others. BERKELEY EARTH Seven older models missed the mark by as much as 0.1°C per decade. But the accuracy of five of those forecasts improved enough to match observations when the scientists adjusted a key input to the models: how much climate-changing pollution humans have emitted over the years. That includes greenhouse gases and aerosols, tiny particles that reflect sunlight. Pollution levels hinge on a host of unpredictable factors. Emissions might rise or fall because of regulations, technological advances, or economic booms and busts. To take one example, Hausfather points to a famous 1988 model overseen by then–NASA scientist James Hansen. The model predicted that if climate pollution kept rising at an even pace, average global temperatures today would be approximately 0.3°C warmer than they actually are. That has helped make Hansen’s work a popular target for critics of climate science. Hausfather found that most of this overshoot was caused not by a flaw in the model’s basic physics, however. Instead, it arose because pollution levels changed in ways Hansen didn’t predict. For example, the model overestimated the amount of methane—a potent greenhouse gas—that would go into the atmosphere in future years. It also didn’t foresee a precipitous drop in planet-warming refrigerants like some Freon compounds after international regulations from the Montreal Protocol became effective in 1989. When Hausfather’s team set pollution inputs in Hansen’s model to correspond to actual historical levels, its projected temperature increases lined up with observed temperatures. The new findings echo what many in the climate science world already know, says Piers Forster, an expert in climate modeling at the United Kingdom’s University of Leeds. Still, he says, “It’s nice to see it confirmed.” Forster notes that even today’s computer programs have some uncertainties. But, “We know enough to trust our climate models” and their message that urgent action is needed, he says. The new research is a useful exercise that “should provide some confidence that models can be used to help provide guidance regarding energy policies,” adds Hansen, now director of the Climate Science, Awareness and Solutions Program at Columbia University. He communicated with Science from Madrid, where world leaders are gathering this week for the 25th annual United Nations climate conference. Delegates from around the world are negotiating how to implement emissions cuts agreed to at the 2016 meeting in Paris. Meanwhile, a U.N. report issued last month showed greenhouse gas emissions have continued to climb since then, and that many of the biggest polluting countries aren’t on track to meet their promises.