2016 Arctic cyclone, update 1

As announced in ASI 2016 update 5 a very large cyclone is raging in the Arctic, as we speak. According to Environment Canada the storm's current central pressure is 970 hPa, but it was 968 hPa 12 hours ago, which is probably the lowest it will go. I've combined the weather map with yesterday's Uni Bremen sea ice concentration map, for geographical orientation and the storm's position in relation to the ice pack:

 

There hasn't been a marked effect on the ice as of yet. On the Forum Wipneus reports a large drop of 170K in the Cryosphere Today sea ice area numbers he calculates. This is the third largest August daily drop in the last decade, but Wipneus explains it is partly due to flash melting in the Canadian Arctic Archipelago. A large drop in NSIDC SIE numbers of 122K is entirely due to the CAA, but it would be even larger if it weren't for ice in the Laptev Sea 'unflashing' into the view of the SSMIS satellite sensor aboard the DSMP F18 satellite.

I expect some more flashing tomorrow in the regions that are directly affected by the storm. Not only is there a lot of ice jutting out towards the East Siberian and Chukchi Seas, there is also a 'bite' developing towards the pole. It can clearly be seen on this animation of Uni Bremen SIC maps. Also note the movement in the last two frames, due to the storm. This movement will become more marked in the next 2-3 days:

But back to the storm. As explained in the ASI update, a pressure of 968 hPa isn't as low as the 963 hPa of the Great Arctic Cyclone of 2012 (GAC-2012), but it is very low nonetheless. It's difficult to classify the storm, especially as it is still ongoing, but soon after GAC-2012 a paper was published by Simmonds and Rudeva to ascertain the storm's ranking according to their methodology:

The plot shows that AS12 was at the tail of the distribution and, at 966.38 hPa, was the lowest in our record, beating the previous deepest (966.94 hPa) (for a storm at 06UTC 7 August 1995) by 0.56 hPa. The next lowest central pressure, 969.23 hPa, was associated with a cyclone at 06UTC 22 August 1991, followed by the fourth lowest storm central pressure in the earlier part of that month 00UTC 7 August 1991 (970.47 hPa).

Their central pressure of 966 hPa is 3 hPa higher than the one reported by Environment Canada while the storm was ongoing. If the same applies to this storm, a central pressure of 971 hPa means there have been at least four stronger Augusts storms in their 1979–2012 database. However, they do not look at central pressure only, but also at intensity, radius, depth and longevity.

In this regard it's interesting to have a look at what the  ECMWF model is forecasting for the next 6 days (click for a larger version, and go to the ASIG Forecasts page for daily forecasts):

The storm loses strength, but doesn't fade away completely. In fact, the forecast beyond these 6 days is showing a re-intensification of the storm. Below is an animation of the entire 11-day ECMWF forecast, as provided by the Tropical Tidbits website, which shows the cyclone's forecast central pressure:

The cyclone maintains a central pressure of around 980 hPa for a couple of days, but on day 7 and 8 it restrengthens with the help of a couple of fellow cyclones, after which it goes turbo boost to 959 hPa. I think it's unlikely things will play out like this, as forecasts beyond 5-6 days become very unreliable. Still, it may be an indication that this storm is planning on sticking around.

Which brings us to the two main questions. First: What will this do to the ice? Will it cause massive flash melting, greatly accelerating ice melt through wind, waves, churning and Ekman pumping? Will there be a large polynya near the North Pole? Or will the cyclone bring so much cold with it that a lot of the ice that drifts away from the core into the periphery manages to hold on until the real refreeze starts in September?

And second: Can this storm be labelled a Great Arctic Cyclone? What we're seeing now, is pretty intense, but maybe not all that Great compared to GAC-2012 and other large August storms. To paraphrase famous philosopher Karl Pilkington: It's not a Great Arctic Cyclone, it's an all right Arctic Cyclone. It's the All Right Arctic Cyclone of 2016. ;-)

However, this may change if the storm lingers and re-intensifies next week. Stay tuned.

Comments

[wayne]

Good report Neven!

Wherever the Cyclone Centre lies there will be more open water if sea ice is dominant. I think the damage done so far is the rotation of sea ice into warmer waters:

http://eh2r.blogspot.ca/2016/08/1st-gac-summer-2016-preliminary-effects.html

The scattering of last few days which slowed extent rates are now leading to greater melting because sea ice once in a pack, is now surrounded by warmth.

[navegante]

Thanks for the update.
All I can say is that, in view of the minimum pressure graph you show, this is as much an outlier as the GAC. It won't have so swift consequences though because the ice out of the main pack is clearly in better shape; most of it will finish melting gradually, but it is also later in the season.
As for a hypothetical continuation, it better stay well centered in the Arctic inflating the pack, otherwise it could promote much more ice melting just before the end the season.

[Neven]

JAXA has reported a century break for the 16th: -109K.

There's a blog post on Jeff Masters' Wunderblog by Bob Henson that is well worth reading: The Great Arctic Cyclone of 2016: After Four Years, a Summer Sequel

[Jim_pettit]

Excellent. It's going to be very interesting to see what happens (or doesn't happen) over the next several days as ARAC 2016 rages on...

(Speaking of: kudos for the Pilkington paraphrasation; the "China" episode of "An Idiot Abroad" is one of the funniest things I've ever seen on TV.)

[wayne]

Oh Yea, Neven,

If it rotates the entire remaining pack counterclockwise, "to the right"
appears to be near the centre, it is a GAC!

We have 21st century super fast evidence:
http://eh2r.blogspot.ca/2016/08/1st-gac-summer-2016-preliminary-effects.html

[D]

The cyclone re-intensifies in 72 hours to 973mb north of the Canadian archipelago. Beyond 3 or 4 days no model is reliable in the Arctic but the dynamics keeping the cyclone near the pole will not change for weeks. Note that the wind fields are advecting warm air at low levels into the system. At this time of year the coldness is generated by radiative cooling over the ice. Warmer air from surrounding areas is pulled into the low and is cooled and lifted up.

Obviously cold air does not tend to rise but this situation works because radiative cooling aloft is very effective over the ice near the north pole in mid-August. The air is rapidly cooling at 500mb over the pole this time of year. The polar vortex is beginning to form for the coming winter.

-Fish

[wayne]

D ,

It would be interesting to know whether the Coast Guard Weather Station near the Pole is on board ship or set up on sea ice. There seems to be a great difference between buoy stations and the icebreaker. These temperature differences are not unusual and can happen at different small altitudes differences.

The great amount of scattered sea ice from 1st GAC 2016 will have repercussions for days to come, note that when the Cyclone changes location there seems to be a pause in greater melting, dispersion over warmer waters, automatically so when a pack ice moves over open water, has two steps, lesser extent drop followed by eventually great extent plummeting numbers.

http://eh2r.blogspot.ca/2016/08/2nd-day-gac-north-pole-situation-looks.html

[Kris]

Wayne wrote:

We have 21st century super fast evidence ...

Another evidence, shelves 'en masse' are pushed (again) towards the Barrow coast line, to be dissolved there (surprisingly) rather quickly.

Anyway, looks like major events are in the pipe line in the Beaufort and Canadian Archipelago zone, as well as the Laptev Sea.

[viddaloo]

Amazingly, the cold year completely without any melt momentum and with only a tiny Arctic cyclone is 4 days ahead of the super–melt year with the Great Arctic Cyclone.

Big: http://i.imgur.com/AA7jTc7.png

[Neven]

It is indeed amazing. Imagine what would have happened if there would have been 2-3 weeks of sunny weather during June and July.

[wayne]

Since summer of 2012, there has not been a sunny summer with near perfect compaction circulations throughout. From October 2012, there has been new weather with a different thinner icescape. 2016 overall weather compared to 13-14-15 was a warm winter, twinned with ENSO peaking in December 2015, turning rapidly towards La-Nina in spring. Cloudy warm winter, abnormally sunny spring, the worse case scenario. The larger question was always: can sea ice disappear in summer without perfect weather for melts: sunny, warm temperatures and a great deal of compaction? The answer was just given, yes. It is a threshold year not quite the point of no return, but very close to it, after all without ENSO Playing a major role, 2016 might have been yet another 13-14-15 melt summer. According to the holistic construct approach, 2013 melt season was bad, even though extent numbers were surprisingly high, but thinner sea ice from 2012 onwards was always vulnerable despite poor melting weather. Finally one must not forget, ENSO was always about, for millions of years there has been quite a few 'worse case' El-Nino-La-Nina scenarios, the difference between history and the very recent past, since 1998, was over all ice thickness and extent has not been recovering from a downward trend to nothing.

[wayne]

This is very cool; I am use to observe isobaric lines marked on sea ice by big High Pressures, but JAXA might have captured it for Low pressures:

http://eh2r.blogspot.com/2016/08/2nd-day-gac-north-pole-situation-looks.html

Look again closely.

[John Christensen]

How the storm is slowly impacting the ice:
The DMI forecast shows that for now the surface current north of 80N will stay reduced, but that by Aug. 22/23 - if the storm stays in place - surface currents also in the 80-90N area will increase significantly, indicating further deterioration of ice pack integrity:

http://ocean.dmi.dk/anim/index.uk.php

[John Christensen]

wayne said;

"The larger question was always: can sea ice disappear in summer without perfect weather for melts: sunny, warm temperatures and a great deal of compaction? The answer was just given, yes."

I guess this is the classic 'half-empty/half-full' discussion.

My take on the past freeze and melt season was this:
- October '15 to April '16 saw near perfect conditions for record low extent and volume by Sept. '16, as I also mentioned back in May.
So the question in my mind for this melt season was this:
Was the unfavorable melting conditions observed starting early/mid June (And then not to forget the low melt pond index) really enough to prevent a May/June record low ice pack in all aspects (Extent, area, volume) from staying record low in all of these aspects by September?
And the answer to that question seems to be yes, but I wouldn't place my vacation savings on this anymore with the massive cyclone in place, doing what it does very well at this time of year..

[viddaloo]

It is indeed amazing. Imagine what would have happened if there would have been 2-3 weeks of sunny weather during June and July.

Yup. How does 2016 extent compare, so far, to prior years? Looks like the gap to the rest of the herd is bigger than ever. Amazing with such poor melt weather.

Big: http://i.imgur.com/dKLU3xn.png

[Neven]

There was a lot of wind at the start of the melting season, causing lots of open water to show up in the Beaufort and Chukchi Seas, and 2016 quickly built up a lead of around 1 million km2. It's only after that, during the crucial months of June and July, that weather was poor for melting. If it weren't for exceptional weather conditions during April and May, the 2016 trend line would be in the middle of the herd.

This information can't be conveyed by an annual average graph.

[John Christensen]

Agreed Neven, and adding to this that volume growth in the past freezing season already was extremely low.

[wayne]

Hi John,

I disagree, the Wrangel pan handle would have disappeared without a GAC, the melt pond forecast was off because it needs integration with snow surface depth. Not only off by a little, need I remind we past 5.2 million a month in advance before the GAC?

Rob Dekker simple mathematical approach was also proven more correct. Again and again. way in advance, I also repeated that simple statistics were not in favour of any conservative forecast as well. Reality is not progressive, conservative nor a variance between the two philosophical approaches, it is dry, impartial, observable and especially cruel to philosophies. It only has allegiance to Nature.

[viddaloo]

Rob Dekker simple mathematical approach was also proven more correct. Again and again. way in advance, I also repeated that simple statistics were not in favour of any conservative forecast as well. Reality is not progressive, conservative nor a variance between the two philosophical approaches, it is dry, impartial, observable and especially cruel to philosophies. It only has allegiance to Nature.

It would be cool, though, if conservatism could somehow be magically transferred to the Earth systems. I'm sure the Military has pondered the thought.

[John Christensen]

wayne,

We certainly don't need to agree, although we did agree that conditions were very unfavorable by late spring.

But then reality kicked in, in the form of weather, not conservatism.

Cyclonic real weather caused PIOMAS to go from lowest volume by June 1st to 4th lowest by August 1st.

Whether you are in agreement with PIOMAS numbers or not, do you recognize that volume dropped less in this period than was the case for e.g. 2011, 2012, and 2013?

If you do recognize that, did it fit well with the statistical approach?

Now weather is having a very unfavorable impact on sea ice, not due to any change in weather, but due to the improbable continuation of a cyclonic weather pattern.

The probability of weather patterns to remain constant for this long cannot be high and therefore the current reality would not be derived at from a statistical approach.

However, if you take the sum of a positive and a negative event, then the sum of improbable real events can cause reality to look very much like the outcome of a statistical approach..

[navegante]

The storm goes on for several days more. If it can be considered a single system, then according to the metrics of the cited paper http://dx.doi.org/10.1029/2012GL054259
it should represent a tremendous outlier of the "lifetime" distribution.
Moreover, the radius of the storm keeps expanding and then contracting again.
What the hell is this freak?
In comparison, the GAC was come and gone. This is a GPAC, great and persistent.

[Aaron Lewis]

Perhaps; the recent and current conditions in the Arctic take some of the "Great" out of the 2012 august event. Perhaps 8/12 was only the first of of a new class of weather events?
E.g., more water vapor and heat in proximity to sea ice drive more interesting wind events.

[navegante]

"Rob Dekker simple mathematical approach was also proven more correct."
Because his model touched the sweet spot of extreme simplicity and capture of relevant physics. It amazes me year after year. In 2013 it was an early-sobering assessment that not many were willing to swallow, myself included. This year it ended in the "alarmist" tail of the SIPN but as you say, from the coldness of the numbers.
Now it does not matter if extent goes to 4.6 or 4.0. The prediction already contains a fundamental aspect that we are witnessing and that other models miss: much of the anomalous heat accumulated early on in oceans AND NH land bare of snow shows up very badly in August.

[Magma]

For those with fallible memories, the July 2013 post in which Rob Dekker gave a simple predictive formula for minimum September ice extent is here:

http://neven1.typepad.com/blog/2013/06/problematic-predictions.html?cid=6a0133f03a1e37970b01901e13f96f970b#comment-6a0133f03a1e37970b01901e13f96f970b

[Magma]

That seems to load slowly or inconsistently.

Neven reposted it here as a guest comment, maybe that will work better:

http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html

[www.facebook.com/profile.php?id=100000035525134]

This blog is a treasure. I read it several times a day and forget to thank you. So, let me remedy that.

Thank you.

[navegante]

Yes thx for reminding. A 4.5 M km2 prediction at that moment was, as I said, sobering. The average expectation then was under 4 M km2 if not under 2012 for many.
Of course 2013 went even higher.

[wayne]

Spot on as usual Aaron

"Perhaps 8/12 was only the first of of a new class of weather events?"

Why not? There is much more open water . The Arctic Ocean is becoming bluer.

[wayne]

John

Cyclonic real weather caused PIOMAS to go from lowest volume by June 1st to 4th lowest by August 1st.

Whether you are in agreement with PIOMAS numbers or not, do you recognize that volume dropped less in this period than was the case for e.g. 2011, 2012, and 2013?"

No

"However, if you take the sum of a positive and a negative event, then the sum of improbable real events can cause reality to look very much like the outcome of a statistical approach.."

Sorry, my head hurts reasoning this :(

[viddaloo]

However, if you take the sum of a positive and a negative event, then the sum of improbable real events can cause reality to look very much like the outcome of a statistical approach..

I suggest the math approach was right all along, and that what you refer to as "improbable real events" aren't really that improbable, only surprising to an observer who's got the wrong map when trying to read the terrain. Case in point: Cyclones, clouds, fog, waves etc as the new face of summer melt.

Also, we shouldn't forget in the heat of the battle what statistics really is, and that most climate variables are based on statistics, as climate is the statistics of weather over a long time period. With global warming we have a scientifically established long–term statistical warming trend, and thus we are able to predict (the purpose of science, according to many) and extrapolate in order to become more enlightened about our future on this planet.

I know statistics and math have gotten a bad reputation around these parts — some referring to calculations as 'mathsturbation' — yet ironically every piece of info on the Arctic peddled on this blog is derived from the use of — you guessed it — statistics and math.

[Susan Anderson]

fwiw, viddaloo, I think mathturbation (without the s) refers to bad or villainously mauled statistics. I think it comes from Tamino, who does it right, though it might have been somebody like Rabbett.
https://tamino.wordpress.com/?s=mathturbation

[wayne]

I further elaborate by highlighting your point John:

"Cyclonic real weather caused PIOMAS to go from lowest volume by June 1st to 4th lowest by August 1st."

In here lies a serious contradiction, how does extra cyclonic activity becomes active when during the said thinner years of sea ice had no GAC's? Would it be possible to have significant weather this summer if it was not for the greater presence of moisture from greater open seas? In the Arctic, the very presence of open water 'attracts' cyclones, so I can't reconcile over all thicker sea ice with greater cyclonic activity, having stronger Lows than the summers of 2013,14 and 15.

To top it off, 2016 will continue to offer a serious challenge to 2012 for #1 minima on record:

http://eh2r.blogspot.ca/2016/08/challenge-to-1-minima-sea-water.html

[John Christensen]

viddaloo said:

"I suggest the math approach was right all along, and that what you refer to as "improbable real events" aren't really that improbable, only surprising to an observer who's got the wrong map when trying to read the terrain."

OK,let's test that itis not just the clarity of hindsight leading you:
I said on June 3rd that the AO index was starting to turn negative and that overall cloudiness would increase, possibly slowing down the melt in June.
List me just one single comment from anyone on this blog, who in May or June had the right map and said we should anticipate cyclonic weather over the summer.

Just one, please.

[John Christensen]

wayne said:

"In the Arctic, the very presence of open water 'attracts' cyclones"

You are quite wrong on this wayne.

You should read the article below, if you haven't already:

The Summer Cyclone Maximum over the Central Arctic Ocean
Mark C. Serreze and Andrew P. Barrett, 2008, Journal of Climate

From the abstract:

"A fascinating feature of the northern high-latitude circulation is a prominent summer maximum in cyclone activity over the Arctic Ocean, centered near the North Pole in the long-term mean. This pattern is associated with the influx of lows generated over the Eurasian continent and cyclogenesis over the Arctic Ocean itself. Its seasonal onset is linked to the following: an eastward shift in the Urals trough, migration of the 500-hPa vortex core to near the pole, and development of a separate region of high-latitude baroclinicity. The latter two features are consistent with differential atmospheric heating between the Arctic Ocean and snow-free land. Variability in the strength of the cyclone pattern can be broadly linked to the phase of the summer northern annular mode [also known as Arctic Oscillation, N.]."

It is the difference in temperature between ice-covered sea and snow-free land causing the cyclone maximum during summer, not the open water.

My point with also the comment above to viddaloo is that I did not notice anyone anticipating the central Arctic to be cold enough this summer to create the conditions required to sustain the cyclonic weather pattern, and it was certainly surprising to me as well.
Once the AO index starting trending towards negative in June, then the probability of cyclonic weather increased, and with shorter breaks, we have primarily seen cyclones moving to and fro in the CAB and neighboring seas ever since.

[viddaloo]

fwiw, viddaloo, I think mathturbation (without the s) refers to bad or villainously mauled statistics. I think it comes from Tamino, who does it right, though it might have been somebody like Rabbett.

Susan,

I don't even want to know what "doing it right" could mean in this context! :)

[John Christensen]

Yes, you are getting a bit off topic here Susan. ;-)

[viddaloo]

John, I'm with wayne on this one. Arctic cyclonic activity changed in 2012 and we all need new maps to understand the terrain.

To clarify my point about the math approach being right all along, I imagine the sum of positive feedback effects to be greater in a melt season with lower annual average extent, whether albedo or cyclones or waves or something yet unknown is dominant.

The Arctic — or more precisely, the Arctic heat — will find a way to kill more ice. The exact form it takes is irrelevant, and anyone watching only one or two of these forms is destined to be wrong in his understanding and prediction for the melt season.

[Rob Dekker]

Regarding the predictive method (using ice area and extent and land snow cover), it is interesting to see how that evolved this year :
- At the start of May, it was pointing at 3.5 M km^2 (albeit with a large standard deviation), while
- at the start of June, the data suggested 3.8 (still with a large standard deviation), and
- at the start of July, the prediction was 4.1 M km^2, with a nice and tight standard deviation (see the July SIPN report).

And note that due to the reducing standard deviation, the actual probability of the September minimum ending up around 4.1 actually did not reduce very much over the months.

This progression of the prediction suggests what we all know already : That despite a flying start, the melting season was not very conducive to melt. It also suggests that influence of weather is clearly present, but limited. After all, the difference between 3.5 and 4.1 is not THAT large.

As for the June prediction (of 4.1), I still stand by that. It is the number we would get for 'average' weather over July, August and September.
July was clearly negative for melt, August may be positive for melt (stirring up lots of heat from the ocean during this storm).
As for September, I think that there are large ice areas that are isolated from the main pack, which will melt out in September, bringing the September minimum rather close to the expected 'average melt' prediction of 4.1.

But time will tell.

[John Christensen]

viddaloo,

This is a futile discussion unless you would actually read the article referred to above - which I can see you haven't - and then explain how the Arctic cyclonic activity since 2012 is different from what Serreze and Barrett have observed in the period 1958-2005.

[John Christensen]

Rob,

I agree with your summary that the June/July weather have been somewhat more favorable to sea ice compared to the negative impact of the August GAC - at least from what we can see so far, so that Sept extend should be above the May prediction and more in line with a prediction made in June.

And sorry, I could search for the answer also, but are you predicting the lowest daily volume or the Sept average extent?

[John Christensen]

How I love the classics, see this:

Reed & Kunkel:
Journal of the Atmospheric Sciences 17(5):489-506 · September 1960

From the abstract:

"On the basis of a number of synoptic and synoptical-climatological studies, the following picture of the arctic circulation in summer is presented.

A secondary baroclinic zone, distinct from the polar front, develops along the northern shores of Siberia, Alaska and Canada. Cyclones which originate in this zone, and to a lesser extent in the polar frontal zones to the south, frequently invade the central Arctic.

The stagnation of these lows near the pole leads to a high frequency of occurrence of low pressure centers and a weak area of low pressure in the mean.

There is no evidence for the often assumed semi-permanent anticyclone near the pole.

The disturbances of the polar region in summer are shown to be similar to typical middle-latitude storm systems.

The question of the representativeness of the present results, which were based entirely on data for the five summers, 1952 to 1956, is considered, and it is concluded that the characteristics of the circulation during these summers were not significantly different than during a number of years, dating back to 1894, for which expedition data were available."

[John Christensen]

"It is concluded that the characteristics of the circulation during these summers were not significantly different than during a number of years, dating back to 1894, for which expedition data were available."

With that in mind and Henry Harries' research (1896) on Arctic thunderstorms, see my comment on the "Iced Lightning", it seems like Arctic summer cyclones have been the norm for quite some time.

It is clearly not the increased areas of open water since 2007 or 2012 that are causing these.

However, the impact of the Arctic summer cyclones is certainly much more severe now when occurring mid/late August than in the past, due to the poor state of the ice pack..

[wayne]

John,

I read the classics, pre satellite era stuff too. They were good with what they had, we are much better now. 2012 had a GAC, 2016 had at least one GAC, it is a coincidence of ice conditioning the entire circulation system over spring and summer. This includes land surfaces as well:

"Its seasonal onset is linked to the following: an eastward shift in the Urals trough, migration of the 500-hPa vortex core to near the pole, and development of a separate region of high-latitude baroclinicity. The latter two features are consistent with differential atmospheric heating between the Arctic Ocean and snow-free land. Variability in the strength of the cyclone pattern can be broadly linked to the phase of the summer northern annular mode [also known as Arctic Oscillation, N.]."

Almost flawless description , I would have left out AO though. There is more cyclonic activity now, because more thicker sea ice gives rise to Anticyclones. So this is why in my forecast dated in April , I placed a Cyclone where it occurred. The contrast of land to sea referred to is also playing out between open water and sea ice. Therefore ECMWF forecast of latest GAC was suppose to be at the Pole, reflecting the embodiment of your cited paper, that science was in its model. But reality brought the GAC to linger between water and ice, a perfect Arctic heat engine. So even ECMWF has to catch up with the reality of changing icescapes.

[John Christensen]

"because more thicker sea ice gives rise to Anticyclones."

wayne,

Where in the literature do you find any support for thicker sea ice giving rise to anticyclones during summer time in the Arctic?

[wayne]

The entire ARCTIC satellite data archive of the last 30 years in my head! Also available in hard copy if you are nice to NOAA, DMI or NASA

[John Christensen]

wayne,

Did you actually read the abstract from Reed & Kunkel (1960) above:

"There is no evidence for the often assumed semi-permanent anticyclone near the pole."

If the anticyclone was not in place in the good old cold days with plenty of MYI in the Arctic during summer, how could your mental archive of satellite data from the past 30 years show differently?

And how would Serreze and Barrett in 2007 draw the opposite conclusion than you based on the same satellite data?

Again, if you cannot point to any reference in the literature for this unusual claim, I do not buy it.

[Rob Dekker]

Regarding the 4.1 projection :

are you predicting the lowest daily volume or the Sept average extent?

I'm projecting Sept monthly average, using June data.
Here are the details of the method :
https://www.arcus.org/files/sio/25738/sio-2016-july_dekker.pdf

Note that the formula given is slightly different than the formula I used in my first blog comment back in 2013.
Back then, I used the 1995-2012 period to calibrate, which resulted in a 4.5 M km^2 prediction for Sept 2013.
Now I use the 1992-2015 period to calibrate, which performs better for the upside outliers and would have predicted 5.1 for 2013.
This new formula is the same I used last year, and at that time it was spot-up (4.6).

Overall, here is what this method would have produced over the past 24 years :

[John Christensen]

Thank you for providing the details again Rob - great work, and I agree with the simplicity of the approach and significant skill in predicting the Sept avg. extent!

[Cato Uticensis]

Sometimes we tend to assume that the Arctic is an isolated area which does not "communicate" with the rest of the planet in terms of synoptic configurations. I have heard several statements like "open water generates LP in the Arctic" or "more ice generates HP" and the like.

Unfortunately things are much more complex IMHO. For example, the persistence of a very strong HP at the high latitudes of the Pacific ocean has forced LP systems to move to the Arctic as the main circulation has never been able to win the opposition provided by the subject Pacific HP.

This could mean that the root cause of such a cloudy and unsettled summer in the Arctic could be found in the patterns of ocean-atmosphere climate variability such as, for example, the AMO or the PDO.

And it is rather intuitive that small masses of water whose temperature is close to 0 C are less impacting than the dynamics of much bigger and warmer water-atmosphere systems in the Atlantic and Pacific oceans.

When I asked a professional meteorologist about a potential negative feedback relevant to the lower Arctic ice extension in summer, he replied that in principle a negative feedback cannot be excluded, but the origin of such feedback should be carefully investigated, as the impact of cold waters on the "local" formation of LP systems in the Arctic is negligible, if not laughable at all.

[Rob Dekker]

Cato said :

the persistence of a very strong HP at the high latitudes of the Pacific ocean has forced LP systems to move to the Arctic

I suspected that that "ridiculously resilient ridge" over the North Pacific had something to do with it all, but is there any evidence that such a HP zone over the North Pacific creates LP systems over the Arctic ?

[wayne]

With respect to horizon refraction, sea ice always offers illusions needed to deconstruct. The same applies for JAXA AMSR2 , 2013 was bad year for sea ice, and so does the numbers not say, but that 15% sea ice minimum per grid magic always is a challenge:

http://eh2r.blogspot.ca/2016/08/north-pole-sea-ice-what-we-can-see-2016.html

2016 looks worse because it has marginally more sea water per grid.

[NeilT]

"List me just one single comment from anyone on this blog, who in May or June had the right map and said we should anticipate cyclonic weather over the summer. "

John,

I tend to post that kind of stuff on the forum. But what do you think??

https://forum.arctic-sea-ice.net/index.php/topic,1493.msg75686.html#msg75686

May 5th.

"Still I'm waiting for it to stall"

https://forum.arctic-sea-ice.net/index.php/topic,1493.msg76912.html#msg76912

May 16th

"It's all getting a bit rapid isn't it? Although I note that Barrow has stopped melting in it's tracks with the cold and the ice crush on the coast... Elsewhere though, very interesting."

https://forum.arctic-sea-ice.net/index.php/topic,1493.msg78246.html#msg78246

May 27th

"At the risk of sticking my neck out to have my head chopped off, there are a lot of similarities I see with other seasons. Large ice loss the year before, warm winter leading to very early melt. Followed by a stall in June and a race to catch up and finish in July and August. Never quite making it."

https://forum.arctic-sea-ice.net/index.php/topic,1493.msg79711.html#msg79711

June 9th

"All it takes, later in the season, is cloud and cold and the sea could be right back to normal.

Yes, the ice will be seriously damaged and weakened. But it will pull back the pace of the melt."

https://forum.arctic-sea-ice.net/index.php/topic,1493.msg81156.html#msg81156

June 23rd

"So whilst the storms and the heat transport from the south will have a heavy impact, especially in volume with bottom melting, the final coup de grace will be by the sun and the sun has been heavily masked this year in the CAB."

[John Christensen]

Hi NeilT,

Sorry; I had moved to a different thread, so did not read this - indeed it seems like you had your neck out early in the season with these comments, I'm impressed.

I stayed quite pessimistic until I saw the AO index moving towards positive and the ecmwf forecast showing the potential of cyclonic pattern in the CAB, first week of June I believe..