bluewave

53 minutes ago, ORH_wxman said:

Greenland is actually having a historically cold summer. Kind of weird obviously in the recent warm context but it's a reminder that natural variability still plays a large role. 

Either natural variability or the early emergence of the CCSM4 summer pattern in response to climate change. The NH summer circulation since 2013 bears a strong similarity to the presentation below. 

https://ams.confex.com/ams/94Annual/webprogram/Paper235210.html

Interesting increase in NH snow cover for June compared to recent years. The highest in over a decade.

2 hours ago, chubbs said:

July often reverses the June 500 mb tendency in the arctic with 2009+2015 being recent high height years in July and 2010+2012 relatively low.

 

 After record breaking -AO and KB block last fall, the PV has mostly been in charge. While we had some transient Arctic blocking episodes, but the PV quickly makes a return.

44 minutes ago, chubbs said:

Hopefully not the sun.

It's funny how the pattern reversed right after the paper was published.

http://onlinelibrary.wiley.com/store/10.1029/2012GL053268/asset/grl29604.pdf;jsessionid=F7950891CB18B3DB5580C02EC912A4A1.f01t03?v=1&t=j4ppf2qo&s=29436c163ab48e25e8f4989445de41091a8d6ccd&systemMessage=Wiley+Online+Library+'Journal+Subscribe+%2F+Renew'+page+will+be+down+on+Wednesday+05th+July+starting+at+08.00+EDT+%2F+13.00+BST+%2F+17.30+IST+for+up+to+75+minutes+due+to+essential+maintenance.

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.

26 minutes ago, chubbs said:

Interesting charts. Highlights the difficulty in predicting sea ice, particularly a record low, with any lead time. Note though that the trend in 925 mb temps is upward so the dice are slowly being loaded.

While the overall annual temperature  trend is an unmistakable up, it would be interesting to know what changed after the 2012 summer. To get a 6 year historic stretch of dipole patterns during the summer and then a reversal is pretty extreme 500 mb behavior.

17 hours ago, ORH_wxman said:

Also, probably one of the more underrated events during the whole decline of sea ice in the past decade-plus is the winter of 2007-2008. 2007 might not have been a complete game-changer had the 2007-2008 winter not exported a ton of that compacted multiyear ice. While the summer of '07 melted out a lot of volume, even more was exported the following winter...the '07 summer pushed/compacted all the MYI leftover from the 2006 season (and previous seasons) toward Greenland/CAA and then a really hostile winter/spring pattern proceeded to export a lot of that ice...expediting the transition from a lot of MYI to mostly FYI.

June officially continues the post 2012 pattern of a more active polar vortex and cooler temps.You can see the long range ensembles continuing this general pattern right into July.

15 minutes ago, ORH_wxman said:

2012 and 2011 were fairly different in volume by September though, 2012 was clearly lower...they were close in July. A much better example IMHO would be 2007...it had a much higher September volume than years like 2013 and barely lower than 2009...yet it had one of the lowest extents/areas at the minimum due to the extreme compaction (caused by the weather)....way lower than 2009/2013.

You are right. That was probably the better example of Volume vs extent divergence. 2007 was the year of the mega dipole. Remarkable how a version of the summer pattern repeated much of the time until 2012 and then abruptly reversed.

21 hours ago, csnavywx said:

PIOMAS actually stayed slightly below 2012 -- or a statistical tie, so it definitely hasn't lost much ground over the past 2 weeks. Most of the gap closing occurred early in the month.  Current anomaly is the lowest on record. As far as the state of the pack is concerned -- it's definitely weaker on the Pacific and ESS-Laptev front and definitely stronger on the Atlantic/Kara side.

The dipole shuts down after D5 (as far as the OP runs are concerned) and a cool PV pattern is dominant on the ensembles. This year has waffled rapidly back and forth, so we'll see if that continues.

It's interesting how big a difference the extents can vary with similar volume depending on weather conditions. We saw the divergence between 11 and 12 extents on similar volume due to the much more hostile weather pattern in 12.

JAXA looks like it's on target to finish very close to last year if there is an average 2007-2016 melt rate for the rest of the summer.

1 minute ago, forkyfork said:

it says a lot about the state of the ice that mundane melt weather could still bring a top 5 low finish

IMHO the 2005-2007 period pretty much reset the whole Arctic background state. Arctic amplification really took off at that time when the September avg extents started regularly falling below 6 million sq km on NSIDC. We didn't even need a 2012 record minimum the last few years to set the extreme Arctic warmth records. 

50 minutes ago, ORH_wxman said:

There's actually a pretty good dipole pattern that gets going later this week, but it doesn't look like it will last more than a few days....but I also recall that July 2015 didn't initially look like it was going to last, but it was able to for most of the month. We'll have to see.

We would need a solid dipole pattern to lock in to have a chance of challenging 2012. Otherwise, it's going to be another year that the 2012 record holds.  Seems like the really extreme Arctic conditions for the most part since 2012 have been during the winters instead of the summers from 2007-2012. 

21 minutes ago, ORH_wxman said:

The rapid regression of PIOMAS seems to suggest that it might have been a little low in May versus reality. Hard to say for sure. We'll see what it does in the next couple weeks.

If this cooler pattern continues, then it might not really matter if we know the exact volume for sure. 2012 and 2011 weren't all that different on volume in August and September. But the 2012 record warmth with the weather pattern made all the difference between the two extent finishes in September. This June is continuing the post 2012 stronger polar vortex pattern vs the 2007-2012 raging dipole regime. We would need a July 2015 rapid reversal to really accelerate the melt. But that kind of reversal isn't showing up in the longer range guidance as of yet. Even Greenland is enjoying a below average melt compared to recent years.

PIOMAS actually pulled back closer to the pack the last few weeks.

More uncertainty about the actual thickness this year due to the divergence between PIOMAS and CryoSat. NSIDC mentioned it in a recent discussion.

Data from the European Space Agency’s CryoSat-2 satellite indicate that this winter’s ice cover may be only slightly thinner than that observed at this time of year for the past four years. However, an ice-ocean model at the University of Washington (PIOMAS) that incorporates observed weather conditions suggests the volume of ice in the Arctic is unusually low.

Coolest first half of June at Utqiaġvik (Barrow) since 1974, 4.5°F (2.5°C) below the 1981-2010 normal. You know the weather patterns are really out of whack  when it's 36 on January 1st in Barrow and can only reach a high of 38 degrees during the first half of June.

https://mobile.twitter.com/AlaskaWx/status/875793934043291648/photo/1#

1 hour ago, csnavywx said:

Yeah, the EPS is now pretty adamant that just about the entire basin goes cold. I'm beginning to think the current +PDO/warm ENSO stretch is inhibiting any lengthy dipole development. There have been a couple of papers hinting at this outcome recently. You had one a couple years back relating to this issue as well, I believe?

Yeah, the flip occurred right around the record breaking March 2013 -3.185 AO. That's when the dominant blocking shifted from the Atlantic to Pacific sector. The +PDO recently set a record breaking 40 positive months in a row.Must be related to AGW, Arctic, tropics, Atlantic, Pacific ,and rossby wave linkages.

The -425 m PV is one of the strongest that we have seen in June. So yet another June post 2012 without the strong 2007-2012 dipole making an appearance.

I don't think that reaching technically ice free in September is the important benchmark to focus on. The key number appears to have been dropping below 6 million sq km on a regular basis around 2005 in September. That's when Arctic amplification really took off.

Month...Year...Station...Rank

3...2010...EWR...7...NYC...6...LGA...5...JFK...4...BDR...2...ISP...3

4...2010...EWR...1...NYC...1...LGA...1...JFK...1...BDR...2...ISP...2

5...2010...EWR...4...LGA...5...JFK....4...BDR...4...BDR...4...ISP...5

6...2010...EWR...2...NYC...4...LGA...2...JFK...1...BDR...2...ISP...1

7...2010...EWR...3...NYC...2...LGA...1...JFK...1...BDR...3...ISP...2

8...2010...EWR...10...LGA...8...BDR...10

9...2010...EWR...5...LGA...6...JFK...7...BDR...7...ISP...7

...............................................................................................

4...2011...EWR...10

6...2011...EWR...9

7...2011...EWR...1...NYC...5...LGA...10...JFK...2...BDR...4...ISP...3

9...2011...EWR...7..LGA...10...BDR...4....ISP...4

11..2011..EWR..5...NYC...6...LGA...6...JFK...5...BDR...3...ISP...4

12..2011..EWR...5...NYC...5..LGA...5....JFK...7...BDR...3...ISP...6

................................................................................................

1...2012...BDR...8...ISP...7

2...2012...EWR...3...NYC...2...LGA...2...JFK...1...BDR...1...ISP...2

3...2012...EWR...1...NYC...2...LGA...1...JFK...1...BDR...1...ISP...2

4...2012...LGA....4...JFK...4...BDR...3...ISP....4

5...2012...EWR...7...JFK...3...BDR...3...ISP...3

7...2012...EWR...5...JFK...6...BDR...7...ISP...7

12..2012..EWR..10...LGA..8..JFK...10...BDR...7...ISP...5

................................................................................................

7...2013...EWR...5...NYC...8...LGA...3...JFK...3...BDR...1...ISP...2

................................................................................................

12..2014..BDR...10...ISP...9

.................................................................................................

5...2015...EWR...2...NYC...2...LGA...3...JFK...2...BDR...2...ISP...3

8...2015...EWR...7....NYC...4...LGA...4...JFK...2...BDR...3...ISP...4

9...2015...EWR...3...NYC...1...LGA...2...JFK...1....BDR...1...ISP...1

11..2015..EWR...1...NYC...1...LGA...3...JFK...2...BDR...4...ISP...1

12..2015...EWR..1...NYC...1...LGA...1...JFK...1...BDR...1...ISP...1

.................................................................................................

3...2016...EWR...3...NYC...4...LGA...3...JFK...3...BDR...3...ISP...2

7...2016...EWR...9...LGA...4...JFK....5...BDR...5...ISP...5

8...2016...EWR...2...NYC...3...LGA...1...JFK...1...BDR...1...ISP...2

9...2016...EWR...3...NYC...5...LGA...3...JFK...5...BDR...2...ISP...5

10..2016..BDR..9...ISP...8

11..2016..EWR..9...LGA...5...JFK...7...BDR...10

...............................................................................................

1...2017...EWR...10...LGA...6...JFK...6...BDR...1...ISP...6

2...2017...EWR...1....NYC...2...LGA...1...JFK...1....BDR...2...ISP...3

4...2017...EWR...4...NYC...2...LGA...2....JFK...2...BDR....2...ISP...1

9...2017...EWR..10..LGA...8...JFK...7....BDR...8...ISP...4

10..2017..EWR...1..NYC..1....LGA...1....JFK...2...BDR..1...ISP...1

.....................................................................................................

2...2018...EWR...2....NYC...1...LGA....2....JFK...3....BDR...3.....ISP....1

5...2018...EWR...6....NYC...6...LGA....2....JFK...5....BDR...4.....ISP....4

8...2018...EWR...5....NYC...9...LGA....2....JFK...5...BDR....2.....ISP....4

9..2018....EWR...7....LGA...6...JFK.....8....BDR..6...ISP.....3

......................................................................................................

4.....2019....EWR...10...NYC...8...LGA...10...JFK...10...BDR...9.....ISP...5

7.....2019....EWR...7.....NYC..10...LGA...3....JFK....4....BDR...3.....ISP...2

9.....2019....LGA...8

10...2019....EWR...9...ISP...#7

....................................................................................................................

1....2020...EWR...9...NYC...9...LGA....7...JFK...6...BDR...3....ISP...6

2....2020...EWR...6...NYC...6...LGA....8...JFK...4...BDR...5....ISP...3

3....2020...EWR...7...NYC...8...LGA....5....JFK...5...BDR...3...ISP...5

6....2020...EWR..10..LGA...3...BDR...5.....ISP....5

7....2020...EWR...5...NYC...7...LGA...1.....JFK...4...BDR....1...ISP....4

8....2020...EWR...10..LGA...5...BDR...3...ISP....6

11..2020...EWR....4...NYC...1....LGA....1...JFK...4...BDR...5....ISP....4

.................................................................................................................

3....2021...LGA.....9....JFK....10.....BDR....8

6….2021….EWR…..2…..NYC….6……LGA……5…..BDR….ISP…..6

8….2021….EWR…..2…..LGA…..6…..JFK……10…..BDR….3…..ISP….5

9…2021…..EWR…..4…..LGA…..7…..JFK……7……..BDR…..5….ISP….4

10..2021….EWR…..1…..NYC…..6…..LGA….3……..JFK……3….BDR…..3…..ISP….2

………………………………………………………………………………………………………………….
 

7…..2022……EWR…..#2….LGA…..#6….JFK….#4…..BDR…#10….ISP….#7

Endless summer...

It's so warm up there that we actually just had a small daily loss in extent on NSIDC.

The Arctic stations data for October shows the unprecedented nature of the extreme warmth.

Chart courtesy of Richard James

http://ak-wx.blogspot.com/2016/11/arctic-warmth.html

New record low October average extent of 6.40 million sq km. This beats the previous October 2007 record by 400K.

This Brian Brettschneider 925 mb October temperature chart shows how extreme this record warmth was in both absolute value and aerial coverage across the Arctic. As impressive a warm Arctic, cold continent(Eurasia) pattern that you are going to see.