bluewave

While the ESS is finally freezing up, Chukchi extent remains at record low levels for the end of October.

Daniel Swain is probably one of the best sources of information on this topic. While all these California wildfire posts probably belong in a different thread, the information below helps people understand the issues involved. https://insideclimatenews.org/news/13112018/california-deadly-wildfires-climate-change-dry-autumn-late-rainy-season-swain-interview What does the recent data show in California? And how are these changes impacting overall rainfall? We are starting to see a trend towards drier autumns in California. It's somewhat new, it's just emerging from the noise, one might say, but it is actually there. This year is going to add another data point in that direction. It matches climate projections. There has long been an expectation that California's so-called shoulder season precipitation would probably decrease—that's autumn and spring. Now what we're starting to see is, especially in the autumn, that process now appears to be underway. It's both an emerging observation but also a projection for the future, a future that maybe isn't really the future any more. That actually doesn't necessarily mean the overall amount of precipitation is decreasing. There's a growing overall concentration of water in the rainy season. Our research suggests that concentration will be a pretty strong indicator of California's future climate. You've made the point that it's problematic to ask whether climate change causes a specific event. Why is that? In any sort of natural system there's never really, in any context, a singular cause of anything. It depends how you define causation, which then is a non-trivial task. It ends up being more meaningful to say, look, we're going to have fires no matter what. Whether they're caused naturally by lightning, by totally innocent human error or by more malicious human intent. It doesn't really matter what started the fire. But the question is, what factors contribute to what happened after the fire starts. The real question is not so much what caused it, because ultimately it doesn't really matter. The question is what made it as bad as it was. Then you can get an answer that, yes, there is a link between wildfire behavior intensity and climate change. As climate change progresses, what is expected to happen with wildfire season? When it comes to wildfire trends, the last five years in California have really been something else. It's really been hard to watch. it's pretty rare to see such large, dramatic step changes as what we've seen in California in the last five to 10 years. We've broken every record, and we've broken them several times. Largest, most destructive, deadliest—all

Highest rainfall total in CT again. https://nwschat.weather.gov/p.php?pid=201910280141-KOKX-NOUS41-PNSOKX WESTPORT 3.04 801 PM 10/27 CWOP

NSIDC put out a tweet about the new record departure.

It sure is.

This was the warmest June through September melt season on record.The earlier areas of open water had more time to absorb the extra heat. So now it’s taking longer for the Arctic Ocean to release the extra heat back to the atmosphere. Perhaps warm water influx through the Bering Strait also played a role. But I have no way of measuring that. Recent winds (drift circulation) and warmer ocean waters from heat gained during the early spring melt-out

2019 continues to expand its record breaking daily low extents for late October. The NSIDC 5 day extent is now 5.503 million sq km as of October 20th. This is well below the previous lowest for the date set in 2007 at. 5.946 million sq km. It also places this year 726 k lower than 2012 which was 6.229 million sq km.

That anomaly grew a little from yesterday. Now at -3.075 as of October 18th. So 2019 continues as the lowest at 5.310 compared to the 5.663 in 2007 and 5.852 in 2012.

Updated for the second breaking storm of the month. New October Record Low Pressures in New England https://www.washingtonpost.com/weather/2019/10/17/powerful-weather-bomb-socks-new-england-with-wind-gusts-mph-knocking-out-power-more-than-half-million/

Updated for 10-16-19 10-17....Norwich, CT...6.15”...numerous 3.00”+ amounts across the area https://nwschat.weather.gov/p.php?pid=201910171436-KOKX-NOUS41-PNSOKX

They usually release it in December.

The Arctic Ocean must have absorbed an impressive amount of heat over the summer. Current 5 day NSIDC extent as of 10-16 is 5.170 million sq km. Extent was 5.422 on 10-16-12. So the unusually slow extent gain pattern continues.

The very slow Arctic sea ice extent gains continue. The NSIDC 5 day extent just fell below 2012 for a new mid-October record low of 5.118 million sq km. The previous record lowest extent value for October 15th was 5.240 million sq km.

Updated for the first record breaking storm system to make headlines this October. 2019 Record Early Season Snows For Upper Rockies And Plains https://weather.com/storms/winter/news/2019-10-14-record-snowiest-start-season-october-northern-rockies-plains

Absolutely. Records have been falling throughout the year since 2016. The 2012 minimum is the one record that hasn’t been surpassed since then. Probably a less important data point relative to the bigger picture. Data courtesy of Zack Labe and NSIDC Record low #Arctic sea ice extent months - @NSIDC data (satellite-era from 1978/1979) --------------------- 2018 : January 2018 : February 2017 : March 2019 : April 2016: May 2016: June 2019: July 2012: August 2012: September 2012: October 2016: November 2016: December

This is the 3rd October stall in extent gains since 2016. But 2019 is starting from a lower point so it was able to drop lower than 2012.

The one day NSIDC extent figure is in a virtual tie with 2012 as of October 11th. 2019...4.998 million sq km....2012...4.964 Five day average difference is a little greater. 2019...4.959...2012....4.684 This is only the second time that the sea ice extent was still below 5 million sq km as late as October 11th.

Impressive stall in sea ice extent gains this week. It allowed 2019 to pull a little closer to 2012. NSIDC extent

Updated for the 8th warmest September at LGA. 9...2019....LGA...8

Notice the much greater amplitude of the Arctic pressure pattern swings since 1990. This would seem to match the 2009 corals study.The record summer Arctic dipole pattern from 2007 to 2012 and new lowest extent. Rapid reversal in 2013 and 2014. Then stronger dipole anomalies in 2016 and 2019. Continuation of the long term Arctic sea ice decline with very choppy volatility from year to year. https://www.sciencedaily.com/releases/2009/01/090113101200.htm Swings In North Atlantic Oscillation Variability Linked To Climate Warming Anthropogenic (human-related) warming does not appear to be altering whether the NAO is in a positive or negative phase at multi-decadal time scales,” said WHOI paleoclimatologist Konrad Hughen. “It does seem to be increasing variability. Clearly, this has implications for the future.” “As temperatures get warmer, there’s potential for more violent swings of the NAO — the phases becoming even more positive and even more negative,” Hughen added. “If the NAO locks more into these patterns, intense storms will become more intense and droughts will become more severe.”

NSIDC extent dropped to the second lowest minimum on record. 2019 was effectively tied with 2016 and 2007. https://nsidc.org/arcticseaicenews/ Table 1. Thirteen lowest minimum Arctic sea ice extents (satellite record, 1979 to present) RANK YEAR MINIMUM ICE EXTENT DATE IN MILLIONS OF SQUARE KILOMETERS IN MILLIONS OF SQUARE MILES 1 2012 3.39 1.31 Sept. 17 2 2019 2007 2016 4.15 4.16 4.17 1.60 1.61 1.61 Sept. 18 Sept. 18 Sept. 10 5 2011 4.34 1.68 Sept. 11 6 2015 4.43 1.71 Sept. 9 7 2008 2010 4.59 4.62 1.77 1.78 Sept. 19 Sept. 21 9 2018 2017 4.66 4.67 1.80 1.80 Sept. 23 Sept. 13 11 2014 2013 5.03 5.05 1.94 1.95 Sept. 17 Sept. 13 13 2009 5.12 1.98 Sept. 13 Values within 40,000 square kilometers (15,000 square miles) are considered tied. The 2018 value has changed from 4.59 to 4.66 million square kilometers (1.80 million square miles) when final analysis data updated near-real time data, dropping 2018 to a tied ninth position with 2017.

That’s a remarkable stat. Just saw it posted on twitter. Record warmth and high pressure over the Arctic since May. https://mobile.twitter.com/AlaskaWx/status/1175034044578295808 https://mobile.twitter.com/ZLabe/status/1170022132216029185

Very impressive Arctic Amplification this September with so much open water. https://www.arctictoday.com/arctic-sea-ice-is-close-to-its-annual-minimum-extent-but-thats-just-part-of-the-picture/?wallit_nosession=1 As the autumn equinox looms and winter darkness approaches, Arctic sea ice has dwindled to what appears to be one of the lowest minimums in the satellite record. “We are basically right now in a dead tie for second place,” Mark Serreze, director of the National Snow and Ice Data Center, said on Wednesday. Ice extent — defined as the area where there is at least 15 percent ice coverage — dropped to 4.1 million square kilometers on Tuesday, matching minimums set in 2007 and in 2016, according to the Colorado-based NSIDC. It will take a few more days to know whether this year’s minimum has been set and the freeze season has started, Serreze said. Total ice extent can waver up and down at this time of the year because of shifting winds and a contest between freeze at the highest latitudes and continued melt in the more southern parts of the Arctic, he said. This year’s minimum extent has no chance of matching the record-low 3.4 million square kilometers (1.32 million square miles) hit in 2012, Serreze said. Still, it fits into a trend to more open water over longer periods of the year, he said. All that open water reinforces the warming cycle in the far north, strengthening the phenomenon known as Arctic Amplification, he said. When waters lack ice cover, they absorb more solar heat, he said. “You’ve got to get rid of all that heat,” he said. “Where does that heat go? Up into the atmosphere.” While annual minimums are useful markers for long-term trends, the expanding durations of open water are turning out to have more immediate significance, said Rick Thoman, climate scientist with the Alaska Center for Climate Assessment and Policy at the University of Alaska Fairbanks. That is especially the case for the waters off Alaska — the Bering, Chukchi and Beaufort seas — where ice has been especially scarce, even in the past winters, he said. The official Arctic-wide minimum extent is only part of the picture, he said. “For Alaska, it doesn’t make much of a difference if it’s No. 1 or No. 4. There hasn’t been any ice anywhere near Alaska for a very long time and the water that’s there is extremely warm,” Thoman said. In the waters off northern and northwestern Alaska, sea-surface temperatures were generally running 3 to 6 degrees Celsius (5.4 to 10.8 degrees Fahrenheit) above normal during the second week of September, according to data gathered by ACCAP. That sets the stage for a delayed freeze season, he said. “We can be absolutely certain that freeze-up in the Beaufort, Chukchi and at least the central Bering will be late,” he said. Delayed freeze likely means a warmer-than-normal fall and, when the winter freeze arrives, ice that is thin and more susceptible to midwinter meltdowns similar to those that occurred in the past two years in the Bering and the Chukchi, he said. The past years’ winter ice loss may have been highly unusual, but repeat occurrences could become more common if southerly winds return, Thoman said. “I think you’ll see the big collapses like we’ve had in the past two years. That requires that sustained southerly flow. We won’t see that every year,” he said. Thoman noted that with the exception of the extreme low in 2012, annual minimums over the past decade have been generally in the same ballpark. That is because the very high-latitude ice, unlike ice at lower Arctic latitudes, has relatively brief period of the year when there is direct sunlight shining on it and causing melt from above, he said. “We have melted all the easy, low-latitude ice now,” he said. Melting out ice at the highest latitudes will require a different process, he said. “That’s going to come from the ocean. That’s going to come from underneath,” he said. Serreze, too, said the highest-latitude ice has lingered despite widespread melt elsewhere in the Arctic. At those very high latitudes — for now — there is still multiyear ice that survives melt seasons, he said. But more changes are expected in the future, he said. “We are kind of in new territory,” he said. “We have not been here before, so every year we’re learning.” https://mobile.twitter.com/ZLabe/status/1175055129290010624 Well above average temperatures over nearly the entire #Arctic Ocean so far this September. This is especially found in areas where there is a lack of sea ice cover.

NSIDC 5 day trailing average extent dipped to 4.153 million sq km on 9-18. http://nsidc.org/arcticseaicenews/faq/#average-vs-daily Values within 40,000 square kilometers (15,000 square miles) are considered tied. Why do you use the 5-trailing average to announce the minimum/maximum and not the daily extent? We use a 5-day trailing average to smooth out the day-to-day variability from the influence of weather (such as storms causing false retrievals) and coastal or surface effects on the data. Five days is a typical synoptic timescale that helps create a continuous curve that is easier to follow and interpret. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Lowest 5 day average 3.387....2012-9-17 4.153....2019...9-18 4.155....2007-9-18 4.165....2016-9-10 4.344....2011-9-11 4.433....2015-9-9  4.586....2008-9-19 4.615....2010-9-21 4.656....2018-9-23  4.665....2017-9-13

Values within 40,000 square kilometers (15,000 square miles) are considered tied. Very large daily drop for so late in the season. ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx Lowest 5 day average 3.387....2012-9-17 4.155....2007-9-18 4.165....2016-9-10 4.170....2019...as of 9-17 4.344....2011-9-11 4.433....2015-9-9 4.586....2008-9-19 4.615....2010-9-21 4.656....2018-9-23 4.665....2017-9-13