bluewave

The Central Arctic continues to set records for low extent as we get close to the beginning of October.

64th day this year at JFK with a 70° or higher dew point. This brings JFK into 4th place. The top 4 years were all since 2016. Kennedy Intl LGT RAIN 72 70

Looking like our first year with 30 or more 90° days and none in the spring or fall. Monthly Number of Days Max Temperature >= 90 for LAGUARDIA AIRPORT, NY Click column heading to sort ascending, click again to sort descending. Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 2010 0 0 0 1 2 12 18 11 4 0 0 0 48 2018 0 0 0 0 4 4 10 16 4 0 0 0 38 2002 0 0 0 2 0 5 14 13 1 0 0 0 35 2020 0 0 0 0 0 5 19 10 0 M M M 34 1991 0 0 0 0 4 9 10 9 2 0 0 0 34 2016 0 0 0 0 3 1 15 10 3 0 0 0 32 1983 0 0 0 0 0 5 11 8 7 0 0 0 31 2005 0 0 0 0 0 7 10 10 3 0 0 0 30 1953 0 0 0 0 1 7 10 9 3 0 0 0 30

Within the last few days. Looks like it’s part of their big upgrade. https://eccc-msc.github.io/open-data/msc-data/changelog_multisystems_en/#tuesday-january-21-2020 A major project to migrate to a new supercomputing infrastructure employed by the Meteorological Service of Canada was completed on January 21, 2020. This successful migration was the result of a joint, sustained effort over several months by experts at the Canadian Meteorological Centre, Science and Technology Directorate, and Shared Services Canada. Over the coming years, this important upgrade will permit further technological transfers from Research and Development into Operations, supporting the continuous improvement of the meteorological and environmental forecast services offered to Canadians and to other federal and provincial government agencies, users, and partners. The official note announcing the migration is available at this lin

Another example of these abrupt precipitation shifts that many areas are experiencing. Very challenging time to be in the agricultural industry. We can swing from one extreme to another.

Very unusual rainfall distribution this month. Portions of Long Island experienced one of their wettest starts to September. This was followed by record dry conditions since then. Heavy rains to end the month will only add to the oddity. 9-10....Pt Lookout....6.47.....Massapequa....5.41...Wantagh Mesonet...4.64....Amityville....4.04....Copaigue....4.05 Time Series Summary for NY CITY CENTRAL PARK, NY Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation Sep 11 to Sep 26 Missing Count 1 1910-09-26 0.00 0 - 1908-09-26 0.00 0 - 1884-09-26 0.00 0 2 2020-09-26 T 0 - 1941-09-26 T 0 - 1917-09-26 T 0

Hartford is hoping for their first 1”+ rain event since late April.

Cool departures should turn warm as we continue the warmer September pattern.

This was their driest ever 05-01 to 9-25. Time Series Summary for Hartford Area, CT (ThreadEx) Click column heading to sort ascending, click again to sort descending. Rank Ending Date Total Precipitation May 1 to Sep 25 Missing Count 1 2020-09-25 6.98 0 2 1964-09-25 8.35 0 3 1957-09-25 8.82 0 4 1965-09-25 9.45 0 5 1914-09-25 10.79 0

Maybe the wetter Euro and UKMET further east will work out for them. I guess it comes down to how much of a phase we get between the two pieces of energy.

The New England crew is probably happy that this is a rainfall departure and not snowfall.

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.