bluewave

The dominant summer reverse dipole pattern of the last 6 years is the main thing keeping the September 2012 record out of reach. But even the more favorable summer pressure patterns for retaining sea ice can't get the Arctic back to pre-2007 ice. I continue to believe that scientists in the future will look back on 2007 as the point which the Arctic shifted to a new warmer state. Remember, we didn't need 2012 finishes to set new Arctic high temperature records since then.

Record low sea ice extent for this date on the Atlantic side. Just an amazing heatwave and ridge near Scandinavia. This follows the record Siberian heat back in June. Sea ice extent has dropped to a record low on the Atlantic side of the #Arctic. In other areas, like the Beaufort Sea, melt has been slower. Each line shows one year from 1979 [purple] to 2017 [white]. 2018 is in red. Daily data over the satellite era is from the @NSIDC. pic.twitter.com/QOqDkNlIXw 8:40 AM - 30 Jul 2018 Yesterday's 18z sounding from Sodankylä recorded 500 hPa geopotential height at 5905 m. With the lack of actual sounding climatology, I checked how that reading compares to reanalysis data: 5905 m is the highest Z500 value in the whole N-Scandinavia, in years 1979-2017. #heatwavepic.twitter.com/6i0q4F8Gvi 3:15 AM - 29 Jul 2018 https://www.washingtonpost.com/news/capital-weather-gang/wp/2018/07/17/scorching-scandinavia-record-breaking-heat-hits-norway-finland-and-sweden/?utm_term=.0638647fb0be An intense heat dome has swelled over Scandinavia, pushing temperatures more than 20 degrees above normal and spurring some of the region’s hottest weather ever recorded. Even as far north as the Arctic Circle, the mercury has come close to 90 degrees. http://ak-wx.blogspot.com/ the central part of Arctic Siberia saw a very large and pronounced warm anomaly, and indeed the Siberian warmth was very extreme by historical standards. At the town of Saskylakh at 72°N (nearly the same as Utqiaġvik), the June mean temperature of 60.0°F was more than 5°F above any other June, with data back to 1936, and the month was a remarkable 17.5°F above the 1981-2010 normal.

7-27-18.....3.00" so far at the Staten Island mesonet. http://www.nysmesonet.org/mesonow#?stid=STAT 1 day:3.00″

Another measure of how strong the reverse dipole is this summer. Yesterday's high of 5.2°C in #Iqaluit, Nunavut is coldest on record for July 17. Previous was 5.4°C in 1978. Records kept since 1946. #NUwx #Nunavut #North 5:28 AM - 18 Jul 2018 Alert, Nunavut hit 10°C for the first time of the year yesterday, 2 weeks later than normal (1981-2010). #Arctic #North #Nunavut 5:36 AM - 18 Jul 2018 Yesterday's high of 0.9°C in Resolute, Nunavut is coldest on record for July 21, beating 1.1°C in 1954. Records kept since 1948. #Nunavut #NUwx #Arctic 6:37 AM - 22 Jul 2018

That recent study is a bit of an outlier. http://www.realclimate.org/index.php/archives/2018/07/does-a-slow-amoc-increase-the-rate-of-global-warming/#more-21540

The Arctic circulation pattern since May has been the complete opposite of 2012.

Looks like the CAB may have set a daily record low temperature with the impressive reverse dipole pattern. http://sites.uci.edu/zlabe/arctic-temperatures/

Lowest surface loss in decades for June. The record late snowpack prevented the local shorebirds from nesting this season. after months of a persistent atmospheric circulation pattern, Greenland is having its least surface ice loss in decades while NW Europe has extreme sun and heat... persistent extremes are an expected signature of #climatechange@PolarPortal #ukheatwave twitter.com/severeweatherE…pic.twitter.com/lsXraH5nuK 6:16 AM - 3 Jul 2018 But Churchill Falls (Labrador) saw its coldest June by a 2C margin; the monthly temperature was 6C below normal. Persistent major circulation anomalies are to blame. pic.twitter.com/Iz5QPeXuBr 8:43 AM - 3 Jul 2018 https://www.scientificamerican.com/article/late-snowpack-signals-a-lost-summer-for-greenlands-shorebirds/ Millions of shorebirds descend on the Arctic each year to mate and raise chicks during the tundra’s brief burst of summer. But that burst, which usually begins in mid-June, never arrived this year for eastern Greenland’s shorebirds, a set of ground-nesting species. Instead, a record late snowpack—lingering into July—sealed the birds off from food and nesting sites. Without these key resources avian migrants to the region will not reproduce in 2018, experts say.

Yeah, 2007 to 2012 was a truly historic period for the Arctic. Some people may not appreciate the rarity of locking in that dipole patttern for 6 seasons in a row. https://onlinelibrary.wiley.com/doi/pdf/10.1029/2012GL053268 Thus we can say that a six year run of near one standard deviation negative excursions (2007–2012) is unique in the 63 year record. To further test the significance of the 2007–2012 AD patterns we randomly generated 10,000 time series, each with 63 points to match the observed time series and with a normal distribution without autocorrelation. For this simple calculation, the chance for having five consecutive values with a negative AD of magnitude greater than 1.0 standard deviation units in a sample size of 63 is rare, less than 1 in a 1000. Yeah, it seems like the SPG region cooling south of Greenland since 2012 is the result of an atmospheric circulation change to more low pressure. SST’s in that region we’re near record levels of warmth prior to the abrupt circulation shift leading into the 2013 summer. Maybe there is some mechanism by which salinity changes following the 2007-2012 record melt can lead atmospheric circulation shifts by months or years?

The NAO averaged for May and June was the most positive on record. This is in stark contrast to the 2012 season which had the 2nd lowest on record.

A -500 meter anomaly vortex is about as strong as I can ever remember seeing in July. This pattern produced the heaviest July snow in Barrow since 1963. The NWS in Utqiaġvik (Barrow) reported 2.0" of snow on Saturday, making this the greatest July calendar day snowfall there since July 4, 1963, when there was 2.9" of snow. #akwx @Climatologist49 @CinderBDT907pic.twitter.com/lkmlmCAG8N 3:13 PM - 8 Jul 2018

Probably one of the the best June outcomes the Chukchi can expect in a post 2007 sea ice era. Chukchi Sea ice extent (from @NSIDC passive microwave data) decreased by 13% during June. The good news: this is the lowest percent decline in June since 2008. The bad news: trend is for more June melt: this would have typical in the 1980s. #Arctic #akwx @Climatologist49 @ZLabepic.twitter.com/KzgcbGy5Tb 11:39 AM - 4 Jul 2018

Chuck, the lower NAO in some of the forecasts is a result of more east based blocking closer to Europe. Pattern back closer to the CAB and Beaurfort is actually one of the strongest July reverse dipole patterns we have seen. Notice the best ridging is focused over Siberia. The models actually have near record low 500 mb heights near the Beaufort for this time of year.

What a reversal from 2012. All the coldest departures in the NH were focused near Greenland and Labrador in June. Right around the extreme cold pool south of Greenland with the slowing AMOC. after months of a persistent atmospheric circulation pattern, Greenland is having its least surface ice loss in decades while NW Europe has extreme sun and heat... persistent extremes are an expected signature of #climatechange@PolarPortal #ukheatwave twitter.com/severeweatherE…pic.twitter.com/lsXraH5nuK 6:16 AM - 3 Jul 2018 https://mobile.twitter.com/Climatologist49/status/1013986099335753733/photo/1 But Churchill Falls (Labrador) saw its coldest June by a 2C margin; the monthly temperature was 6C below normal. Persistent major circulation anomalies are to blame. pic.twitter.com/Iz5QPeXuBr 8:43 AM - 3 Jul 2018

The 500 mb height reversal near the Beaufort in June has been as extreme as it gets. 2007 to 2012 featured the highest sustained heights on record for a 6 year period. 2013 to 2018 has seen a dramatic decline in heights with 2013 registering a lowest single year record.

While this has resulted in a slowing of the rate of sea ice decline relative to the 2005-2012 period, it's still at a level well below the typical late 1990's and early 2000's ice. The extreme Arctic amplification and circulation changes began when the September average extents began to regularly fall below 6 million sq km. In 50 to 100 years, that may turn out to be the more significant number than when the Arctic first went technically ice free.

We are moving right back to a reverse dipole pattern in early July. This has been our typical 2013 to 2018 summer pattern. As long as this continues, we may be able to finish September with an NSIDC average extent not too far from 5 million sq km.

A rare colder than normal month in that region in what has been a sea of record warmth. Technical: ongoing cool wx at Utqiaġvik, Alaska is the largest negative departure of the 30-day running daily standardized temp anomaly since late summer 2014. Illustrates nicely the control by sea ice on Arctic coastal air temps. #akwx #Arctic @Climatologist49 @CinderBDT907pic.twitter.com/PK380UAnXW 9:02 AM - 23 Jun 2018 1pm Friday, Utqiaġvik (Barrow) Alaska hits 40F (4C) for the first time this year. This ties with 1955 as the fifth latest “first 40” in the past 98 years. #akwx@Climatologist49 @CinderBDT907 2:21 PM - 22 Jun 2018

Also a pretty impressive slow down in the melt near Alaska for late June. Sea ice extent around Alaska now running close to the long term average for late June, (passive microwave data from @NSIDC). Early melt in the srn Chukchi Sea has stalled farther north and meltout in the Beaufort Sea is only slowly spreading west. #Arctic @akwx @Climatologist49 pic.twitter.com/d3rbwGXJvV 6:58 AM - 25 Jun 2018

Yeah, CPOM may be close if July and August continue with more low pressure over the Arctic like June. First set of forecasts for the September Arctic sea-ice extent have been collated. Median forecast (4.6M sqkm) is slightly lower than last year’s observed value. The @CPOM_news forecast from @UniRdg_Met is one of the larger forecasts at 5.3M sqkm. arcus.org/sipn/sea-ice-o…pic.twitter.com/kgaROTK7Yr 2:19 PM - 23 Jun 2018

It's as if the historic summer Greenland melt in 2012 really slowed the AMOC. Shortly after that, the cold pool and strong vortex couplet became a persistent feature south of Greenland. The colder waters there seem to go along with more low pressure over the Arctic during the summer. It's pretty much the opposite of the warmer SST's and the summer Arctic mega-dipole from 2007-2012. It will be interesting to see how long this pattern persists. https://www.carbonbrief.org/atlantic-conveyor-belt-has-slowed-15-per-cent-since-mid-twentieth-century https://www.climate.gov/news-features/understanding-climate/summer-2012-brought-record-breaking-melt-greenland

Looks like the HadGEM1 is doing a great job so far. Very impressive considering the paper was first published back in 2012. https://www.the-cryosphere.net/7/555/2013/tc-7-555-2013.pdf Mechanisms causing reduced Arctic sea ice loss in a coupled climate model Abstract. The fully coupled climate model HadGEM1 pro- duces one of the most accurate simulations of the historical record of Arctic sea ice seen in the IPCC AR4 multi-model ensemble. In this study, we examine projections of sea ice de- cline out to 2030, produced by two ensembles of HadGEM1 with natural and anthropogenic forcings included. These en- sembles project a significant slowing of the rate of ice loss to occur after 2010, with some integrations even simulating a small increase in ice area. We use an energy budget of the Arctic to examine the causes of this slowdown. A negative feedback effect by which rapid reductions in ice thickness north of Greenland reduce ice export is found to play a major role. A slight reduction in ocean-to-ice heat flux in the rele- vant period, caused by changes in the meridional overturning circulation (MOC) and subpolar gyre in some integrations, as well as freshening of the mixed layer driven by causes other than ice melt, is also found to play a part. Finally, we assess the likelihood of a slowdown occurring in the real world due to these causes.

It's remarkable how the Oct-May strong blocking ridge pattern over the Arctic finds a way to shift in June. This has been a very reliable reversal over the last 6 years. Notice how the strong Oct-May Arctic blocking pulls back to Siberia/Bering just in time for summer. This seasonal circulation change seems to be the only thing keeping the 2012 record out of reach for the time being.

More favorable for melt, but nothing too extreme looking.The dipole ridge won't be anywhere near as strong as the ridge that was located over Siberia this month. Check out the record heat under that ridge. 31°C (89°F) is mighty impressive at 73N latitude along the Arctic Ocean.twitter.com/EKMeteo/status… 5:21 PM - 23 Jun 2018

September averages have remained in a very narrow range since 2013. It appears to be near the lowest amount of variability since 1980 for a 5 year period. 2017....4.87 2016...4.72 2015...4.63 2014...5.28 2013...5.35