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Thanks, Neven,
On the Forum I just put some musings on the same. One of the "unknowns" is how steering patterns interact with these storms.
The changing character is partly due to large scale reorganisations of the NH atmosphere.
In my own poor words they "get spinned up"by anomalous jet stream branches.
Difficult to model?
As I recall, not much was hinting at the strength of GAC 2012 before it broke loose.

BTW I always wonder why ECMWF publishes different graphics. "Mine" over at the Forum are much more informative. Yours remind me somehow of tonight's spaghetti dinner... always hard to digest.


Remind me again where you got yours, Werther.

I'm a bit conservative. As soon as I'm used to something and it works, I keep using it. When I was younger I would eat spaghetti every evening for three months.


It has certainly peaked and I think will slowly dissipate but I wouldn't be surprised if another one comes along to take it's place, quite soon in fact.

There are a few more sat pics on the blog I put up - it was the only place I had to save the images

Craig Merry

This storm development is precisely why we should be using a more formal naming convention. There's bound to be years where events become more frequent and a range of destructiveness- the need is there to easily recognize a storms' name would help people compare events.

Crop failures would be one of my dreaded consequence - different spaghetti, pizzas, beer, etc :(. And of course how it'll impact football (soccer).


I wonder if we need to go beyond naming conventions and cyclone requirements to talk about what constitutes adequate at-the-time documentation.

True, that can be done 'later' by 'someone else' as very little data is discarded over the medium term and some of it, like reanalysis, might be improved down the road.

However, perhaps we should at least be collecting a multi-faceted baseline description that captures the essence of the event and its special effects and enables our own event to event comparison tables.

You can see the cyclone shaping up in the last 2-3 frames of July to date. I expect effects on the ice motion to lag somewhat in manifestation.

Also noteworthy is a new area of melt ponds moving into upper multi-year ice, just to the left and down from the pole as presented.

 photo tojuly23jaxa_zpsc26a5876.gif


I was musing today that nobody ever talks about 2011. It came so close to beating 2007, but in the end it couldn't seal the deal.

Now it's in third place, and nobody really seems to care about it.

A few days ago the 2013 line kissed the 2011 line and then leveled out slightly.

Here's a visual comparison between the two years:


In 2011 there were areas where the ice had retreated from the coast to a greater extent, but the "core" looked a lot more solid. I don't recall there being any serious storms in 2011 to shred the ice between July 21 and the end of the melt season, whereas this year, storms are forecast. A good storm like we had last year would close the gap and then some.

I see nothing to indicate that we can't bomb past 2011 (and 2007 by default), which would give 2013 at least a second-place finish.

Timothy Chase

Neven wrote, "I'm a bit conservative. As soon as I'm used to something and it works, I keep using it. When I was younger I would eat spaghetti every evening for three months."

I can identify with that some. Between navy and college there was a point that I ate oatmeal three meals a day for two weeks so that I could save enough money to get some books I really wanted. Human Action by Ludwig von Mises and Modern Times by Paul Johnson were among them.


Morning all,

Neven, the charts I prefer can be found on www.ecmwf.int
See the "free access" under the forecast item on the front page.

BTW, CRWS jet stream shows a nice 300Mb swoosh embracing the Low.

Doug Lofland

Just saw that the Alert station on Ellesmere has shot up to a balmy 51 deg F (10.5 deg C) with the barometer falling to 1009 and strong winds from the south gusting to 30mph. http://www.wunderground.com/history/airport/CZLT/2013/7/24/WeeklyHistory.html

Jim Hunt

Having been pointed in that direction by BornFromTheVoid on the forum I've taken to perusing metiociel.fr recently. It offers lots of different models in a consistent and reasonably readable format. By way of example, this is what ECMWF is currently predicting for August 3rd:

The second storm gets a second wind?


It looks like it. The amount of warm air currently around the basin is certainly keeping this thing going. I thought the latest disorganisation was going to puff out over Ellesmere but it's curling around again and continuing to move towards Greenland.

I think this system ( mainly the spinning not necessarily powerful all the time ) will keep going around and around for weeks, getting stronger or weaker depending on ...weather I guess.


That's 10 days from now. The forecast will change.

R. Gates

Craig said:

"This storm development is precisely why we should be using a more formal naming convention. There's bound to be years where events become more frequent and a range of destructiveness- the need is there to easily recognize a storms' name would help people compare events."

Exactly. The naming of storms is actually the best scientific thing to do. It is time this be done.

Wayne Kernochan

Because there will be many cyclones in coming years, albeit few in any given year, I propose a naming convention similar to that for hurricanes. However, rather than first names, to distinguish cyclones from hurricanes, we should use last names. As serious scientists, we should start (as in naming asteroids and species) with the last names of those performing research in this field. Since the members of this blog are in the forefront of said research, we should start with the names of said members. I therefore propose that this cyclone be named Arctic Cyclone Neven.

On a more serious note, I believe that eating the same thing for long periods of time can be characteristic of one's teenage years. I was told at computer science graduate school that a recent entrant had subsisted entirely on mushroom pizza and diet coke for three months, at which point he had to be admitted to a facility for the mentally bewildered. I myself one summer had a regular diet of cheeseburger, fries, and black raspberry ice cream. To keep my weight down, I of course drank diet coke.


Here's what Navy Hycom thinks about ice speed and drift for the next 7 days. The big days anticipated there are 27-29 July. Note the velocity vectors are rather dramatized and do not actually amount to much net movement.

Today is the big day for Jaxa, our main microwave satellite -- the first year to year comparison will be available in about 9 hours. Let's just say 2013 is unfolding quite differently from 2012.

 photo julyStorm_zps09816e24.gif


There's an update to the post. Currently the cyclone's core has a pressure of 977 hPa.

Eric Orr

My question is whether the storm can disturb the upper freshwater layer. If I remember correctly the GAC 2012 shunted the freshwater from the Russian rivers towards the Bering and stopped the replenishment cycle that keeps the saltier water from the bottom of the pack. It may not stick around long enough to cause significant bottom melt.

John Christensen

An observation from DMI Arctic weather images:


You see how the storm has lowered the temperature in the Beaufort area, while quite warm air is being sucked in across the CAA and across Northern Greenland into the CAB.

DMI Forecast (http://ocean.dmi.dk/anim/index.uk.php) still has surface currents in Beaufort slowing down by tomorrow evening (7/25), so hope that forecast will play out, allthough the past few cyclones have been less predictable..

Doug Lofland

Now there has been over 12 hours of 50 deg F+ air blowing from the south at 25 to 40 mph at Alert by the Nares Strait. The barometer was still dropping when the station went offline 3 hours ago. Nice to see some ground truthing to the satellite data. 54 deg F was last reading. http://www.wunderground.com/cgi-bin/findweather/getForecast?query=82.51777649,-62.28055573


Indeed, Doug, a reality check is timely.

Melt ponds are (possibly low salinity) fresh water sitting over 1-2m ice; their temperature is therefore indistinguishable from 0ºC. As is adjacent still air -- with minimal heat capacity of its own -- equilibrated with them.

I've always wondered how the '6m' temperature correlated with buoy *surface* air temperatures. Here of course we have a very windy day and turbulent air.

DMI is showing -2 to -1ºC but off-center with respect to the low. The latter agrees quite well with Jaxa though there's considerable uncertainty in the latter's swath time.

 photo tempSLP_zpsc6b0f48c.gif


@John Christensen

The latest satellite images show those feeder bands very well. It's still huge and gaining heat from all sides of the basin.

To me it seems it wont matter too much about intensity, the spirally ice is going to be moving for days even after this finishes. And IMHO this system will continue well into the forecast time, and continue to push ice into warm water for at least the rest of July if not longer.


Another small update added to the blog post showing the DMI SLP map.


Kate writes, "the spiraling ice is going to be moving for days even after this finishes."

The reversal in circulation over the last few days -- from CW to CCW -- represents a colossal and rather sudden transfer of momentum transfer from atmosphere to ice.

Had the ice been going CCW before the storm, it would be rotating even faster today -- yet this effect may be offset by differential response to reversal, according to ice tensile strength variability.

 photo iceMortionReversal_zpsf4b88341.gif


"represents a colossal and rather sudden transfer of momentum transfer from atmosphere to ice"

which is why I'm thinking that these days it's best to follow weather rather than climate...not sure I'm explaining myself well but I've always thought this year would be bad because of the heatwaves on land. Nothing to do with temps in the arctic itself. A bit radical but there you go.

Jai Mitchell

A little off topic but the Arctic Joule has passed Baillie Island and is now in the entrance of the Northwest Passage. Their update today talks about the largest seas they have seen with very strong winds. They are sheltering in place in a protected area, waiting for the wind to subside.



Since el Lago del Polo Norte is in the news today:

Does surface melt always work towards melting the subtending ice, or can it insulate the ice?

Does surface melt push the ice down into the (ostensibly warmer) water, or does it have no effect?

How does the salinity of the water in the interstitial space serve to preserve or melt the ice?

Finally, is sea ice more like packed snow or more like an ice cube from the freezer? How much space is in there for air and water?


DanP continues his fantastic work over at the forum, constructing high resolution (4900 x 4900 pixels, 9 MB jpg named by first [of 8] days in the mosaic and band combination) cloud-free Modis imagery, which Articio is helpfully hosting with continuous zoom

A lot of great information pops out from these white-on-white after a couple of quick (and reproducible) enhancements. It's going to be quite valuable to have an image after this storm clears.

932 pixels full width:
 photo cloudFree_zps8f3cb06d.jpg


This thing appears to be really chopping up the ice in the Beaufort. Seeing quite a few more cracks and bits of open water. The ice is getting ripped up like tissue paper just north of Alaska.

Dan Ellis-Jones

A-team - Correct me if I'm wrong (and I might be as the arctic.io page isn't loading due to trying to see it on my work computer which is pretty rubbish), but the ice at the top of the image (Beaufort Sea) is very well fractured. Forgive my ignorance, but is this true colour? If so, it's a beautiful example of the difference in albedo of soild MYI and fractured FYI.

It'll be very interetsting to see what's left once the storm clears.


Speaking of interesting, wind speeds are still moving at a healthy clip. I haven't looked at this site before, and thought it apt to post this:



Hit post too soon... Unless I miss my interpretation, there's a band of flow west to east roughly parallel to the Alaska/NWT coast running up to and well over hurricane force. I'm not sure how to interpret the altitude from the map, but still seems pretty intense.

Dan P.

Dan - it is a true color image made from red, green, and blue visible bands. I agree that it does show nicely the difference in albedo between the more and less fractured ice, but there are some cautions to reading the image. For example, the brightest white areas over the ice are generally contaminated by clouds; even though this is an 8-day mosaic and NASA's declouding algorithm attempts to choose low-cloud swaths, some areas were consistently cloudy. The clouds are better distinguished using IR band combinations like this one:

(MODIS Terra 7-2-1)
R: ch 7, 2100 nm IR
G: ch 2, 857 nm near IR
B: ch 1, 646 nm visible red



Fascinating tour around the buoys in the Arctic today.

One example seen here: http://imb.crrel.usace.army.mil/irid_data/2012L_thick.png

Apparently this current cyclone has taken roughly 0.6 m off the top and 0.3 m off the bottom of this particular ice-floe in the Beaufort Sea.

Other buoy data on display here: http://obuoy.datatransport.org/monitor#overview/gpstracks shows Obuoy #7 racing eastwards at the moment at a speed of 1 m/s.

It would not surprise me to see bookmakers give us hint soon, whether the floe will melt before it reaches the Fram Strait.

John Christensen

Let me make a controversial statement (and this is not just because it is raining outside, and I am lacking sugar for my coffee):

This cyclone is not is likely to have any significant negative impact on the ice pack.

Now, why would I claim that?


From the research quoted in this excellent blog entry:

"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"

"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" (AO)

"..fewer cyclones over the central Arctic Ocean during the months of May, June, and July appear to favor a low sea ice area at the end of the melt season."

"Years with large losses of sea ice are characterized by abnormal cyclone distributions and tracks: they lack the normal maximum in cyclone activity over the central Arctic Ocean"

These extracts are from the first two articles references, and which seem to be performing a more complete analysis of past cyclonic activity in the Arctic.

Also looking at recent significant years:

The melt-out was not caused by cyclones, but a massive high pressure, which is very uncharacteristic for the Arctic summer.

Comparing 7/22 of 2013 to the same day of 2012 on CT (http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=07&fd=22&fy=2012&sm=07&sd=22&sy=2013), it is no wonder why the western Arctic ice fully collapsed in August with ice concentration across a large area of 40-60%. We do not know how this would have held up again a high pressure rather than GAC-2012, but I do not see how it would have been retained under any circumstances.

So bring on the cyclones - at least until mid-August when the sun is lower, and a high-pressure area would no longer cause excessive in situ melting.

You can come by my house north of Copenhagen for a cup of free coffee by the end of August if this turns out to be rubbish.

John Christensen

Just make sure to use your bike to get here..

You can come by my house north of Copenhagen for a cup of free coffee by the end of August if this turns out to be rubbish.

And bring some sugar. :-)

Actually, don't bring any sugar. It's as addictive as heroin, and screws up body and mind.



Core pressure back to 981 hPa, according to Environment Canada.

Jim Hunt

P-Maker - Not that I'm trying to make John's point for him, but I'm not sure 2012L's recent melt can be directly attributed to the cyclone, since it was already losing 10cm a day before the cyclone arrived. If anything all this sudden rushing around the Beaufort seems to have lowered the temperature of the water under the ice.

Perhaps a better candidate is 2013C, near Alert? That lost 10cm yesterday, but that's rather more unusual in that location.


@John Christensen
If you use the CT 30 day animation and go back to the beginning of July ( very warm in Alaska if I remember correctly ) Watch the ice off Barrow for the first week of July. The prevailing winds are pushing from Barrow onto the ice. The big wash of red is the heatwave. After the first week, the temps settle down a bit and you can see the ice sort of recover. If you keep the animation going you see the heatwave from Canada ( the one that caused all the flooding ) going north into the NW passage and towards the end of the 30 days you see the start of this storm ( about the 18th ). Now to me this shows how much the actual air temps of the surrounding land can affect thin mushy ice.

I honestly think the ice is too fragile for normal comparisons.

John Christensen


I know, I am seeing the same thing.

I guess the point to be made here (if any) is that the Arctic summer is quite a hostile environment for ice, since you have warmer and salty water beneath, sun around the clock above, and then mixed with the highest frequency of cyclones of the annual cycle.

So even if the cyclones are breaking up the ice, research seems to suggest it is the lesser evil. We will know more by mid-September..


I've been staring at the sat animation for ages tonight. I'm going to agree with a few forecast points I've read/seen

This system is not going away. It's slower and disorganised tonight but across Canada north there are fast bands of cloud, the jet stream curl I see in other pics. It's going to push this mass of air towards Greenland, across Ellesmere... a big wandering mass of energy.

Forecasts have this going until early August. You can predict it following the normal course of air currents and wind up on the European side of arctic, swirling once again from Barents to Kara to Laptev - that is what happened to form that strong little system in the Fram last week. Same type of currents, same type of track, just a bit more north this time. So yes, next week it's still going to be spinning.

I think late August will show a record loss. I'll completely leave my hobby alone if I'm wrong :(


Let me congratulate WUWT for being wrong again, old reliable WUWT screws up again, their prediction (according to Ned) of SIE 4.8 million square kilometers will likely be exceeded today. CT got it at 4.85 yesterday. May I say I am truly impressed with their failing skills. Highly unusual even for humans.

Now back to CT's Graph, truly amazing red zone of ice covering almost the entire pack. That is 60% coverage, this is the year when compaction is missing, the appearance deceives, reality continues.


I didn't know about the annual cycle from that perspective...Does the research cover warmer water? I say this because I also follow the hurricane season ( and tornado season, etc etc ) and so far we have at least a month before the ocean gets to its max temp for the season

lots of colder water because of the storm btw, spread out from everywhere in a big fan ( looked very pretty )

John Christensen

Yes, you will see the graph on the "On persistent cyclones" entry that July has the highest frequency of cyclones, followed closely by August with June third.

The frequency for July/August cyclones is a 2.5 factor compared to Nov/Dec/Jan.

This is based on 1958-2005 data.


I’ve been looking at Barrow for a while now. I’ve noted something we’ve been hearing in quite a few times in the comments.

When the storms start to push the unstable and fragmented ice to the continental shelves where the warm water will drive them out of existence.

Looking at the Barrow 3 day, that is exactly what is happening right now.


Also I note that the SIE figures are still running at an average of 114km^2 daily for July. Then again, July did start on day one with a break very near to 4 century.

I’d have said that things were slowing rapidly if it was not for the > double century break on the 20th.

Also the concentration charts on Uni Bremen AMSR2 are showing more rapid disintegration of the extremities.

Time to update my estimate.


Here are the links to the most recent 7 day Modis reduced-cloud composite -- July 23 -- from Environment Canada. A remarkable change from the previous week:


 photo 23Julyfalse_zps307afa89.png

 photo 23Julytrue_zps8a53a8ed.png

Doug Lofland

Starting to see ice concentration bands from the cyclone on AMSR-2 on July 24, and I brought the video animation current at http://vimeo.com/69836368



The SIE predictions are for NSIDC September average extent, not area like CT does. Our site had an average of 3.2 million sq km for average September extent on NSIDC. I think we will be off by more than WUWT sadly. But still some time to go.


Current NSIDC SIE is 7.45mkm^2


Henry, no WUWT are WRONG again party yet :(, will wait a bit! 2013 trend is close enough to 2012.

Vergent Bill

CT SIA is 4.86. So, there is 2,590K of open water "air" in the "extent balloon". There is a lot of ice extent that does not have to melt.

Crozet Dutchie

2007, 2011 and 2012 converge around Day 211 on CIA, which is 7 days from day 204, and 2013 only needs to drop around 0.6 from 4.85 to 4.25 to join in.

Crozet Dutchie

I mean CT SIA (not CIA) :-)


Vergent, that is right, therefore less compaction does not mean less melting. Its a visual presentation ripe for contrarians to comment on, I am sure they will excoriate like: "there is a conspiracy to make the melt worse than it is" , and all kinds of people will believe them.

But that number you gave is key in understanding current action so far, mega compaction can occur very fast, or scattering can be maintained, there is a slight benefit for scattered ice making freeze up much faster, thus a colder earlier Arctic winter, but we are not in October yet.

Aaron Lewis

I would say that the Arctic has changed since 2005. Now, it has more water vapor over the region. The water vapor rises, condenses, and when the sun is low in the sky (spring & late summer) the clouds are warmed by sunlight. That warming drives a stable spring and late summer low. I doubt if this bit of geometry is in your climate texts.

In the old days, the air over the Arctic was dryer and colder. Snow and ice tended not to absorb sunlight. Lows were driven by other mechanisms.

Heat from direct insolation in this process is trivial compared to the amount of latent heat advected into the region from the south by this circulation. Thus, a bit of heat from sunlight on the sides of the cloud column results in circulation patterns and substantial sea ice melt.

This is a powerful feedback from additional moisture in the Arctic atmosphere.


Most of us here are looking at these storms mostly from the point of view of short-term impact on the ice area. I don't really think the impact will be terribly large there, since the increased cloudiness and precipitation tend to lower absorbed heat amounts. There is a bit of extra heat in the water in the Laptev/East Siberian sector, and divergent ice motion will send some ice closer to warmer coastal water, but actual heat input is decreased by a storm, so I don't anticipate that the net effect will be terribly large.

The larger effect is likely to be on the freshwater budget. Actually, a storm of a few days doesn't have a terribly large effect by itself there either. We are, however, talking about not merely a single storm, but a general trend towards increased cyclonic storms in summer. Surface transport through sufficiently long, thin channels is pinned to 1-d transport, and thus, like the east-west transport at the equator which leads to the El Nino/La Nina climate mode, moves without resistance from the Coriolis force. Even the Canadian Archipelago channels are not sufficiently thin for the Coriolis force to be entirely irrelevant, but they still have a boundary current for each channel, and have very much more transport for a given forcing than an open ocean. The Beaufort Gyre is named for the persistent high pressure over it, which by Eckman pumping stores huge amounts of fresh water. Having persistent low pressure over the Beaufort Gyre is basically breaking Arctic's fresh water piggy bank, and throwing fresh water at both the Arctic Basin and the Labrador Sea deep water formation areas. This would have a larger effect, except that the low pressure systems we've seen in the Arctic in the past two years haven't been in any particular place, but scattered in many places, with much of their effects canceling each other out, and we've seen persistent low pressure systems close to the pole as well.

Deep convection is hard to predict because it has a hysteresis which makes it likely to continue ones it starts, and hard to restart after it stops. My best guess would be that increased freshwater flows from cyclones and Greenland melting would suppress convection in the Labrador Sea, and that increased temperatures would suppress deep convection both there and in the Norwegian Sea. I would guess that we are going to see increased deep convection in the eastern Arctic Basin, where it up to now been only a relatively small fraction of deep water formation. Increased cyclone-driven divergence and increased mobility of thinner ice are on balance increasing the salinity there. I wouldn't even be terribly surprised to see a semi-permanent area of open water and storms develop near there without much quick change in the global ice area indices.

So far, despite all the extra fresh water thrown at it by storms in the Beaufort and Greenland melting, the Labrador Sea deep water formation seems to still be chugging away unlike the period of around 1960-2000 when it was mostly shut down. Despite the sea ice volume being the highest for the date in about 3 years, the melt front between Greenland and about 90 degrees east is farther north than ever for this time of year, the sea ice near the pole is more broken than ever, and above 80 degrees the amount of fresh water in the surface layer counting ice is likely the lowest ever.

The northward march of the eastern Atlantic convection currents certainly doesn't look like it's stopping this year.


Arctic Cyclone Mulches Sea Ice

Arctic scientists are watching in awe this week as a raging summer cyclone tears up what could become a record amount of rotting northern sea ice.

"We're really watching this year with a lot of fascination," said Matthew Asplin, an Arctic climatologist at the University of Manitoba.

Arctic cyclones are driven by low-pressure systems in which winds of up to 100 km/h blow counter-clockwise in spiral more than 1,000 kilometres across. They occur in both winter and summer, but are usually stronger in winter.

Cyclones are not unusual in the Arctic, but seem to be changing in recent years, said David Barber, one of Canada's top sea-ice experts.

"These cyclones are not getting more frequent, but they are getting deeper — which means stronger," he said.

And they're getting harder on sea ice, which they break up through wave action associated with high winds and through rainfall, which darkens the ice and makes it absorb more solar energy. The storms also bring up water from the depths, which is actually warmer than surface water.

Cyclones can destroy large amounts of ice very quickly.

"In 2009, we actually documented one of these events in which large, multi-year ice floes — Manhattan-sized — broke up in a matter of minutes," said Barber.

Last year, a particularly powerful cyclone is thought to have wiped out 800,000 square kilometres of ice. That contributed to record low sea-ice levels at the end of the 2012 melt year.

This year's storm over the Beaufort Sea formed about mid-week and is expected to die out on the weekend.

It isn't as strong as last year's, but the ice is thinner and weaker. As well, the ice has already been pummelled by earlier storms.

"The effects of (the storm) are nowhere near what we saw last August," said Asplin. "But because the ice is thinner and it's already been pre-conditioned, and because there's less volume, it's much more vulnerable to impacts from this sort of thing."

Barber said the ice is getting so weak that new categories have had to be created for it.

"We have a whole new class of sea ice in the Arctic, which we're calling 'decayed ice,'" he said.

"We started seeing it in 2009. It's extremely weak."

Barber said the research icebreaker CCGS Amundsen can do 13.5 knots in open water. Through decayed ice, it can do 13 knots.

Changing sea-ice cover is increasingly being linked to southern weather patterns. The jet stream, which strongly influences weather at mid-latitudes, is driven by temperature differences between the Arctic and the equator, a difference that shrinks with the sea ice.

Ice coverage is slightly above last year's record low but still well below the 30-year average.

Much remains unknown about the role of Arctic cyclones in the annual freeze-thaw cycle. Back when the sea was thick and lasted for years, cyclones tended to spread the ice out and actually increase its extent, said Julienne Stroeve of the National Snow and Ice Data Center in Boulder, Colo. Now, when ice gets spread out, it simply breaks up and disappears.

"As our ice cover has thinned, some of our old rules are changing," said Stroeve.

Asplin said cyclones will be a big part of the research agenda when the Amundsen sets sail for the Arctic again later this month.

"This year has been very stormy. The month of August is definitely one to watch in the Arctic."



Is anyone else noticing this cyclone might be about to get help from another 980-ish low pressure system coming up north from the Bering Sea in a little over a week?


Aaron, that's why I asked if melt ponds always contribute to ice loss.

Just thinking about it, it seems like salt water at -2.9 degrees over old freshwater ice *could* insulate the underlying ice against a 16 degree C air mass, even with albedo taken into account.

I dunno if y'all saw it, but there was a terrific article in Rolling Stone today about Greenland and a man who is studying soot deposits and the effects on albedo. From what I know about snow, melt alone increases albedo and creates a feedback loop because impurities in the snow are brought to the surface. Water on the surface could also serve to wash away soot and other small particles, refreshing the surface and making it white again.


It's kicking off people. Everything is pointing to a huge second storm ( the heat, jet wave strength, position, time of year, sat images, existing conditions )

The latest CT image for the 25th is truly astonishing. I say that knowing where the storm is heading ( across the top of GL ), the strengthening conditions of the low, the heat around Fram and Russian/European coast.

It's all coming together to push ice into warm water, during July/August. What could be worse?



not having a wonderful blog like this to share the news with others would be worse!


Allen W. McDonnell

I have been reading reports lately that indicate a complete absence of Arctic sea ice in early summer could be the trigger to flip the northern hemisphere into the hothouse mode just as it was when last the Earth had 400 ppm CO2 in the atmosphere. Several researchers have been modeling the effect of an ice free Arctic ocean and the majority of runs show that the Ferrel cell of atmospheric circulation would grow from its current Equator to 30 north range and encompass the entire northern hemisphere.




The studies don't say how long the Arctic has to be ice free, it could take a decade or more for the transition to happen once we are there, but at the rate we are going now I don't think it is nearly as far off in the future as we have been lead to believe by the IPCC.


@ Allen W. McDonnell

"... a complete absence of Arctic sea ice in early summer could be the trigger to flip the northern hemisphere into the hothouse mode just as it was when last the Earth had 400 ppm CO2 in the atmosphere."

Allen, what time period are you referring to? If it was over 3 million years ago then you have to take into account that the isthmus of Panama had not yet formed. That changed the ocean currents probably contributing to a warmer Earth.

I'm not saying there wouldn't be a transition just that it could be different (milder?) from the last time we had the same amount of CO2.

Allen W. McDonnell


There are several competing factors all adding into positive feedback scenario's at this point. Around 5 Million ybp and before the Arctic ocean was ice free year around and the currents flowed in a Mediterranean pattern, warm surface water flowed in through the North Atlantic gaps, swirled around in a counter clockwise direction and at least in summer evaporated off enough water vapor that the surface waters because dense warm but highly saline water that would sink into the deepest part of the basin near the Beaufort sea, then escape as a bottom current back into the north Atlantic as the Mediterranean does through Gibraltar Straits today. The Gulf Stream is encrouging further each year on this pattern, if the trend continues the old system will reassert itself keeping warm water entering and preventing freeze up of the surface even during the polar night.

We have already hit the 400 ppm mark as it was the last time the Arctic Ocean was ice free, while it is true the continents are in different configuration now forcing currents to flow somewhat differently 400 ppm isn't even a bump in the road for humanity, we are on track to hit 410 ppm by 2020 and possibly 450 by 2050, that would put us in the ice free regime in the northern hemisphere almost certainly based on newer modeling coming out.

If that all turns out to be accurate based on paleo climate records as it is and the model studies I linked to in my earlier post are true then we could be teetering on the edge of the tipping point and most of us have no idea the edge is even this side of the horizon.

It is that thought that keeps me paying attention.



haha oh yes! This site and Neven and the forum are a wonderful resource, could not follow any of this without it!


And the position of the system tonight is such that it will be drawing warm air across GL north, sucking warmer air from the US as it does so ( more melt for GL in the next day or so for sure )

Also, the winds around Ellesmere and Lincoln/Morris Jesup sat areas of GL are going to come from the south, shifting the hard ice out from land ( over the next few days at least ).

With the direction of spin and ice flow this is going to push the last of the MYI into the danger zones, and all the mushy ice that was sitting at the NP.

When I look at the CT images, there is very little 'purple' left, no hard ice at all.

With spin, temps, wind and uplifting of warm water from the deep I don't think there will be any 100% ice left in a couple of weeks, or even days!


In the latest image of SST from Wunderground, you can see two bright blue lines coming from the SW of GL. That's warm melt water from the ice cap isn't it?



Another very small drop in SIE for the 26th (-21,875). At 7,254,531, 2013 is now in 6th place behind 2007, 2011, 2012, 2010 and 2009.
There is also a huge uptick on DMI 30% SIE which generally foreshadows JAXA by a day or two
Neven, are the current weather conditions likely rto persist?


Hi, Phil. Yes, it will stay like this for the next week or so. The ice pack is being spread, causing upticks on the SIE and SIA graphs, but also increasing the already significant melting potential.

What can be seen through the clouds, doesn't look all that great, so I think that even with weather that's bad for MCT (melt-compaction-transport, trying to introduce a new acronym here) the decline will be steady, just like last year. If there's good MCT weather there could be some more big drops.

Either way, I still think this melting season stands a good chance of ending in second place. Which, of course, would be amazing.


@Neven "ending in second place"

what if...instead of day 261 being the melt end date like 2012, the end date was say 270? What would happen then?



Thanks for your quick response. If the ice gets spread, am I right in thinking that SIA should still drop steadily even though the decrease in SIE is slowing down?

what if...instead of day 261 being the melt end date like 2012, the end date was say 270? What would happen then?

The melting season would end 9 days later. ;-)

There won't be heavy ice losses during those 9 days, but September monthly mean will be lower the later the minimum is reached.

It depends on what data set you're looking at, and whether you're interested in the daily or the monthly minimum.

If the ice gets spread, am I right in thinking that SIA should still drop steadily even though the decrease in SIE is slowing down?

In principle yes, and that's what we see in the Wipneus data set for the past couple of days.

Shared Humanity

Allen W. McDonnell


Wow! Just wow! Anyone who has skipped over this link must go back and read it in its entirety.

Nevin.....this would make a great seperate topic espcially as it links to studies regarding the current shift of the jet stream northward.

Shared Humanity

I'm not saying there wouldn't be a transition just that it could be different (milder?) from the last time we had the same amount of CO2.

If I read the two articles correctly the CO2 levels are really not of particular importance to the bifurcation from hothouse to icehouse climates. The temperature gradient is what is relevant and we know already that the polar regions are warming more rapidly than the equatorial regions.

The fact that this model is predicting a shift of the Hadley cell and a movement north of the jet stream causes me to believe they are on to something. I cannot believe an open isthmus of Panama would have any impact on this hemisphere wide process.

Paul Klemencic

The weather this year hasn't really been good for ice melt, and so I don't think we should be expecting to surpass 2007 (unless we get another major storm in early August - read on below).

We are now entering bottom melt season, where the ice melt primarily uses heat from the seawater, and insolation impact diminishes rapidly. This year, the amount of open water around the pack has been much less than in prior years, and the Beaufort, Chukchi, East Siberian, and Laptev have clearly not gained as much heat from insolation as in prior years. These regions have had a lot more ice to reflect solar radiation. The side of the pack toward Svalbard is in terrible shape, but the extra 400k-500k sq km on the other side will help protect the Central Arctic Basin pack.

The last storm did some damage, but was too far south, hit a more consolidated pack (that helped prevent major wave action and resulting ice loss), and was much weaker and not in the best position to rip the pack apart like the GAC of 2012.

So will we see another major storm in early August? The long term forecast shows another storm forming in about a week, but the forecast is highly unreliable that far out. By mid-week, the forecast will be clearer and more dependable. The position of the next storm appears to be almost identical to the position of GAC12, with the wind field extending almost to the NP. If the long range forecast pans out, and the storm is positioned like GAC12, then the Beaufort and Chukchi will be ripped apart, and the warm air and moisture sucked into the low (from the very hot regions in Siberia this year), will carry a lot of heat in the East Siberian region.

If this storm pans out, I find it interesting that the storm would hit within a day or two of the anniversary of GAC of 2012, and in almost the same "sweet spot" in the Arctic (that is almost ideally located to cause ice extent loss). But I still think would do much less damage than GAC of 2012, since there should be less heat available, and the GAC of 2012 was much more powerful than this year's storms.

The next ten days will tell the tale of the ice melt in 2013.



Thanks for reposting. Fascinating. There are flaws in their model. They are working on those for future iterations. Still, it makes sense and it matches what we are seeing. As the delta T from pole to equator collapses we are seeing the polar and Ferrel cells shrinking. The bifurcation their models exhibit is unsurprising and one of he dragon kings that changes everything.

The mechanics of how that happens now seems to be that as the delta T falls, the Rossby waves slow and the oscillations north and south broaden (a bit like a steams meander changes as the slope from mountain to ocean declines). This then leads to the overlap and merging of the jet streams and the break down of the polar and Ferrel cells leading to a single polar-Ferrel cell state as a transition to the next step where the same thing happens with the expanding Hadley to polar-Ferrel cell boundary and reorganization of the whole system into a single Hadley cell state.

We could probably apply this same model to the gas giants and find five, seven and nine cell variations as the delta T increases. Just as a guess, I suspect the odd count of cells is more stable than the even count. But that is only a guess.

So, as we watch the jet streams merging, we maybe watching the state change in progress. It would not be surprising for this to be very abrupt. And with it, it would not be surprising to see a lot more energy flowing into the arctic from the equatorial regions. At least temporarily this would seem to drive a lot of cold southward near the surface. And that might seriously mask the global warming indicators until the polar ice is gone and the equible climate mode takes over.

Anyway, that is my speculation.



"The weather this year hasn't really been good for ice melt, and so I don't think we should be expecting to surpass 2007 (unless we get another major storm in early August - read on below)."

Was it now Paul?

Look very very carefully at the CT or Bremen map, compared to last year, the Euro to East North American side of the Pole has a great deal less ice, as opposed to Alaskan NWT side. This was because of persistent cyclones. As with the recent one, pushed back ice to where there was open water. The Melting is more on one side of the Pole than the other. The Beaufort Sea ice is in a roller coaster mode. Wait a bit, it will show a great vanishing again.

I am more interested in the Near North Pole open water zones, these are wide, these are new, the melt has been more on the side we are not use to. The regular side is very unstable, extremely interesting, lesser ice thickness causes different weather which in turn causes different mega wide sea ice sculpting. You will be surprised by more new twists and turns to come.

Steve Bloom

Current research seems to point to the Central American Seaway closure as not being a big factor in the Pliocene-Pleistocene transition. Interestingly, there is new strong evidence pointing to the opening at depth of the Drake Passage as having been much too late (~20 mya) to play a role in the icehouse transition of the early Oligocene. CO2 remains the big player.

I wonder how much acceptance there is for these results, noting that there aren't all that many papers or active researchers. Perhaps that's because until very recently it was not considered to be a possible near-future issue? Of course it might explain a lot of things, e.g. the extensive forests of the Miocene and earlier, with dry zones only at the poles. It's also discussed as a possible (the only possible?) mechanism for the polar amplification examined in the Ballantyne et al. paper Neven discussed in the "Arctic Time Bombs" post, although note that the associated mechanisms for heat transport into the Arctic are a somewhat different matter (see the Fedorov et al. paper from earlier this year). I think I'll ask a couple scientists with relevant expertise about all of this, and will post anything I get back.

Sam, noting that a double cell would require upwelling air at the poles, it sure doesn't sound stable!

Also, a transition to single cells would be very noticeable considering just the effect on the storm tracks. I would go so far as to describe as likely amounting to a series of unfortunate catastrophes before things are able to stabilize. Don't forget that ocean currents would also get involved in this.

I think I posted previously on a possibly related phenomenon, although probably most will have missed it in the rush to place bets, but interestingly early this summer the northern jet seems to have been doing somewhat the opposite, seeming to indicate the partial formation of another cell (or maybe I'm misinterpreting what this means). Anyway, see here. Presumably this will have had a relationship to recent weather behavior in the Arctic, although I have no idea what that might be. Note that it's only obvious when viewing average jet position over a period of time. I looked at the SFSU animation when the article first came out and could see only what looked like a series of very transient branches curling up toward the pole, i.e nothing looking anywhere near as defined as the main jet. John N-G says this phenomenon has been observed before, but in a quick search of the literature I wasn't able to find anything.

More to come.


Steve - duh!, of course! Thank you.

It seems likely that any stable system would have to have rising currents at the equator due to heat, and sinking currents at the pole due to cold in the heat engine. So long as there is any delta T to drive the heat engine, this would imply a near requirement for an odd number of bands or cells. Evens will always be unstable so long as the driving force is the heat engine.

So, once the delta T falls past the point of transition, it makes sense that we will see a step change from a three band or cell system to a one band or cell system.

The next question is what markers we would expect for the transition? And as I noted before we may already be seeing that with the apparent merging of the jet streams.

So, if we step change to an asymmetric one band north, three band south setup, how long can that last, and what happens then?

From the geologic record, it appears the asymmetric setup is stable so long as the heating doesn't cause a clathrate break and sufficient warming to melt Antarctica and cause a single band setup to the south.

But the amount of energy we are dumping into the system, and the rate of it seems to make it likely that we are causing an Arctic clathrate break, followed or coincident with collapse of the tundra and release of upwards of 2,000 GT of C in a pulse, to be followed by even more clathrate breaks farther south, etc...

That can't be good. It is hard to see how we can avoid a serious change of state in the system and dramatic warming that eventually results in an ice free world over the next few millennia.

So, in the near term, if we collapse the north to a single cell, what is that going to look like. About the best we can gauge by is the geologic record with very warm cloudy rainy conditions at the pole.

In time, the Arctic will green overt as it did before and crash the system back to current conditions. That will take a lot of time.

With all of our predictive models being based on or current three cell system, I doubt we have any significant insight into what is about to happen. The one thing I think we can guess is that all of our modeling is about to be thrown out as the simple changes states new a new set of conditions rendering the current models obsolete and unhelpful.


Steve Bloom

Much to think about, Sam. "About the best we can gauge by is the geologic record with very warm cloudy rainy conditions at the pole." Not sure which record you refer to. Pointer? Remember that with downwelling at the poles, overall we should expect them to be less wet. If true, that would seem to mean less reflectance and more heat loss, and a higher rate of heat transport to keep things as warm as they are known to have been. I need to look again at the recent Fedorov et al. paper and see if they said anything about polar clouds in this regard. Re the single cell north/triple cell south, I see no particular reason why that couldn't be stable so long as the two poles remained at substantially different temperatures. OTOH that would probably be a temporary situation that would change after the Antarctic ice went. Re the Arctic greening over, if you're referring to the recovery from the PETM it may be that the Arctic Ocean is now too open for that to happen in the same way, azolla being a freshwater genus. (I know my phrasing on this stuff may sound confident, but bear in mind I'm really way out of my depth.)

Dan P.

Major breakups happening in the Parry channel over the last 2-3 days. 4-day animation ending at the end of day 207 (July 26), extracted from MODIS Terra swaths channels 1+4+3, 500m resolution.


Those lines do indeed show the influence of glacial meltwater, and appear just there every year, just north (downstream) of some major glacier outlets including Jakobshavn. The water of course comes off the glaciers cold and not warm. What you're seeing is the ability of fresh water to from a thin stable insulating layer on top of the ocean. The total heat in the top 30m or so of the ocean there is probably even less than in neighboring areas, and those warm areas will disappear quickly with the coming of winter or a storm, but for the moment the surface is quite warm.

See here for a SST image without the gross distortion at high latitudes of that projection. Note the mid-20s C water presently in the Ob estuary, which is a similar thin freshwater layer, but nevertheless indicates very unusual heat content.


We have some very interesting discussion on NH atmospheric re-arrangement in this thread.

I did go briefly through the Lewis/Langford presentation. As it i9s from 28 April 2011, things are two years on their way since.
As I often go through the CRWS Squall Jet Stream images, I have the impression that it reflects exactly what is in the bifurcation-modelling Lewis and Langford presented. It also touches what has been published by FI Dr. Francis.

Neven, though this is hard stuff to crack, it could be well worth a try for a new blog entry.
Because indeed, the repercussions could make any climatic axiom from the last 100 years worthless, we could be out on a limb suggesting anything near confident on the matter.

But, as I’m sweating here in the Netherlands under one more retarding ridge filled with warmth and humidity, I’m inclined to take this seriously. Wish our German neighbours the best today with 38-40 dC near Berlin.

Neven, though this is hard stuff to crack, it could be well worth a try for a new blog entry.

I agree it would be very interesting, but I will be lucky if I can keep the blog going in coming weeks, never mind the hard stuff to crack!

We're slowly entering the building phase and things are getting more hectic by the day (decisions, decisions, decisions). And it's been around 30 degrees for almost 5 weeks now, here in southeastern Austria, with not a speck of rain. Tomorrow we're hitting a peak of 38 °C.

Ned Ward

Congrats on the building phase, but wow the weather sounds unpleasant. it was very hot here earlier, but not bad now.

I wonder what the temps have been like in Sochi this summer, and how all that manufactured snow they stockpiled in preparation for next winter's Olympics is holding up. It'd be pretty sad if they peeled back all the insulating blankets and found that it had all melted...

Kallu Kalakar

Hello, my first comment here in about a year of lurking around. Thank you @neven and everyone else over here, for the great blog and discussions. It has helped mi to further map the extent of my ignorance wrt to the world I live in.

Am too much of a noob to be making any kind of a serious observation, but the melting in Greenland just spiked again. Of course completely in line with the energy moving across GL towards the pole.


In the last year I have gathered that the subject is too complicated to be simplifying to such an extent. But the late high percentage melt area could be pointing to what @kate was alluding to up thread, what if the melt season lasts longer?

@kate "what if...instead of day 261 being the melt end date like 2012, the end date was say 270? What would happen then?"

One of the biggest challenges that I think the scientific community is facing with climate change is the speed. Say 20 years back, one outlier data point meant nothing because the rate of change was slow and you could treat that outlier as a freak event (excuse the simplified language). But now that the rate of change has gone exponential each outlier needs to be taken seriously it could be pointing at a faster rate of change.

Similarly, for the entire hemisphere consolidating into one cell (dunno if I am getting this right). Such an idea 10 years back would have been taken as science fiction. Now, if something like this were to come about withing the next few years it would not really be a surprise.

Optimistically speaking, my apprehensions grow about how much ice will be left at the end of this melt season and how that will effect the weather around the world.

Pessimistically, I am reminded of 'Day After Tomorrow'.

Aand my mental conditioning kicks in, science fiction I tell you... pfft.. nothing to worry about... back to lurking...


Allen, thank you so much for posting those links. I have been looking for more information about this subject for a few years. NH circulation began to undergo distinct changes by late 2009 and now it is pretty clear the circulation is completely different than climatology. SH is getting some knock on effects but is somewhat stabilized by the massive cold of Antarctica.

Allen W. McDonnell

You are welcome, now you can share my bad dreams lol!

All my life I have been fascinated by the environment and paleoclimate because like most kids I loved the heck out of dinosaurs and studied up on the climate they lived in. Tanada over on Peakoil.com posted the first of those two links on the Greenland thread over there and when I saw it I did some searching and found the second link. I shared both of them over here because I thought you would all be interested. The idea that the Earth existed in a dual climate state with the north in the Hothouse while the south was in the Icehouse never really clicked with me until I read that first link. I mean I knew the Icehouse in Antarctica started around 34 Million years ago while the Greenland ice sheet formed much later, but I never really thought about what it meant that Greenland was ice free up until 3 to 5 million years ago. Clearly based on the fossil remains the North was in a cool phase of the Hothouse climate until 5 Million years ago and possibly as late as 2.8 Million years ago. Think about that, the Earth was in two different climate states North and South for at least 25 Million years!

Reading that first link made the two state Earth system really pop out at me, and as someone said up thread it makes all those climate models people have been using obsolete. If the North was in the Hothouse while the south was in the Icehouse, and we know it was, then all those climate models showing equal distribution of climate change are pure fantasy. The North will be back in the Hothouse very soon if nothing else changes, and at that time the South will still be in the Icehouse. That means it doesn't take 4C of temperature rise to flip the whole planet to the Hothouse, it takes 1.5C or so to flip the North, then another 3C or maybe 4C to flip the south. The whole UN set of negotiations based on 2C is completely invalid, by the time we officially hit that we will have tipped over the North into the Hothouse.

Jai Mitchell

Last year we had standing wave patterns that caused heat waves. This year the standing wave has been replaced with a polar jet stream that is now so weak that it is basically split into two, with a variable Jetstream pattern formed around a semi-permanent arctic low that is being fed by high pressure ridges that are being forced up by blocking pattern lows, which now dominate the mid latitudes.

A new game that I like to play with the "denialist" crowd is Find the Jet Stream!!! (it is getting to be a harder and harder game to play. . .)

Jai Mitchell

Sorry, proper link here:

Find the Jet Stream!!!


Dan P. , great catch! This was from a total energy burst from a full moon tidal effect, with strong Westerlies teaming up with the usual current, 3 physical vectors in tandem direction wise, creating a sudden collapse of sea ice, mind you once upon a time at least 1.8 meters thick, with ridges much higher. The greater conclusion from this sequence, 3 direction vectors are very very potent, so much so, massive changes can occur very fast.
For the larger Arctic ocean area, a better map than the Navy one, would be placing placing all vectors at key spots, and from there we can see the future happen before it does. Overall ice conditions over the entire ocean is in such a state, a sudden collapse or wide opening of water can occur anywhere with the right natural collaborations. The Arctic Dipole phenomena is jut but one recognized pattern.


Allen, I think that this time round, the Antarctic may be warmer -- warm enough to tip over faster than the earlier epoch. Or at least, even if it stays in the ice state, there will be significant knock on effects in the SH atmos. circulation due to craziness in the NH, which you can see here:



Allen McD - I just went through the Langford presentation. Yup, I now have a new source of nightmares.

Any sense from the audience as to what we might expect during tip-over, and what might signal it? Are our current weather changes part of that signal?

I also agree, this may want its own thread.


Morning JDallen,

On your questions… my opinions.

First, the current weather changes. I think last winters’ small but significant atmospheric thickness growth over the N Polar region is one of the signs (analyse the NCEP/NCAR data). The geopotential difference was just 100-150 m on the 500-300Mb height. But enough to have an influence on strength of the Polar Jet.

To me it seems that this process is not entirely dependent on present ice/open water coverage in the Arctic Ocean. It has been buiding since the first vast anomaly in ’07.
The build-up is in the cocktail of all parameters, like salinity, structure, temps, etc. Some on the blog refer to the hysteresis. IAW the dependence of a system not just on its present constitution but also on its former state.
I hold this to work not just on a very long or mediate time range, but on the short range too. The re-arrangement, NH atmospheric cells are in, is proceeding in a short-term hysteresis over the period ’07-present.

In it’s first stages, the dipole was characteristic. A new phase has started over the last twelve months. This phase is characterised by repeated SSW’s during winter, rapid spring warming over the Boreal region, probably spring persistent lows over the sea ice.

Specifically; the short term ice/ocean coverage has not much impact on the process, it doesn’t matter much that this season there’s a 300K ice difference in the Beaufort Sea and it hasn’t collected as much heat as last year. I think that was a synoptic scale difference. The re-arrangement is all about zonal hemispheric changes.

As I have guessed before, in this phase the Arctic Sea Ice might not show the most representative part of change. It is possible the expected SIE/SIA/volume crash won’t be imminent.
At least, not this year. Think of a “long tail” and an annual sea ice cover with clearly different properties than the Polar pack ice that used to be.

Most effect is to be expected in this phase over the mid-latitudes, as the Ferrell Cell is fading and the tendency to one single functional atmospheric circulation is gaining importance.

The ridging on the 500Mb level is where the action is now. And out of our sight, in the deeper ocean layers, the patterns are shifting to reflect this within the THC later. That’s on what we might expect, to answer your first question.

To be founded on data…


This year’s second Persistent Arctic Cyclone (PAC) is now dead and gone.

It lasted roughly 6 days with a minimum core pressure of < 980 hPa. It met all the provisional criteria, which I suggested some time ago.

The naming issue is still unsolved, but with the support from Google, I tend to continue calling it “PAC Bush 2013” for the time being.

I just had a quick look at some of the impacts from the storm. Apart from the drifting buoys in the Beaufort Sea, I also noticed a spectacular impact on the ice conditions in the Canadian Archipelago (as also noted by DanP further up this thread).

The HYCOM ice thickness maps: http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticict_nowcast_anim30d.gif illustrate very well, how the thick MYI is being “stuffed” into the various canals on the western side, whereas water is being pulled into the Arctic trough the Nares Strait.

The irony is - if this pattern continues - that we may end up with heavy MYI blocking the NW passage for a while. At the same time the Northern Sea Route is still blocked by heavy ice around Severnaya Zemyla. So the 240 odd ships waiting to get through, may better grab another biscuit, since next week’s weather forecasts nearly all have a new PAC hovering over the Central Arctic. At the same time, there is a tendency to have a high pressure ridge over Greenland. This pattern (as projected already last year) will lead to a strong pressure gradient (20-30 hPa/500-1000 km) situated just North of Greenland, which may drive the remaining MYI into the Fram Strait – blocking also this entry point to the Arctic.


I don't think the ice blcking Vilkitsky Strait is going to hold out much longer, P-maker. I'm almost 100% certain that the Northern Sea Route will be open for shipping in two weeks from now.

But the Northwest Passage could be blocked at McClure Strait, even though the main passage is going to clear in the coming 2-3 weeks.


Seems like the storm weakened some ice over the Chuchki, East Siberian, and Beaufort but the overall effect was fairly small. The numbers aren't looking good for low extent and area this year.

Ron Mignery


Stunning! Am I correct that you are saying that we are now (since 2007) in the middle of the hysteresis described by Langford in Allen McD's link? If so, this is a monumental tipping event that makes SIE a trivial concern.

I have so many newbie questions: how long do you think it will take before the tipping completes? What is THC? Why is ridging on the 500Mb level where the action is now? What exactly is ridging on the 500Mb level? A new thread on this topic would greatly be appreciated.

Lord Soth

A week ago, before the second PAC, it appeared that 2013 was going to catch up to the 2007,2012, 2011 group of years. Now since the PAC of 2013, things have slowed down tremendously.

We seem to be creating a lot of rotten ice, but it is not going away, and these storms are spreading it out. Look at the DMI 30% extent map, it has basically flat line.

August is flash melt month, but is their enough energy to finish a good section of ice off. With the North of 80 temps below average since early April, I don't believe it can be done.

I don't believe however bad the weather is, we will ever return to above 5 million km^2, end of season extents. However from looking at the graphs, my theory may be tested.


@Lord Soth

I am in agreement that we can't flash melt enough of the remaining ice to challenge any records like last year.

I do think there will be some big time loss days coming up with the weakened ice in the Chuchki, Beaufort, and East Siberian Sea. The recent days have been so slow that its almost inevitible that we'll see a couple biggies. You can see the weak ice fanned out in spots ready to disappear.

2009 had a minimum above 5 million sq km. This year is currently close on extent to that year but it appears on area its lower so I don't expect a repeat. I think high 4s is possible this year though.

Allen W. McDonnell
    I have so many newbie questions: how long do you think it will take before the tipping completes? What is THC? Why is ridging on the 500Mb level where the action is now? What exactly is ridging on the 500Mb level? A new thread on this topic would greatly be appreciated.

Short answer, the tipping point could take as little as a decade or as long as a century. THC is the Thermal Haline Circulation aka Gulf Stream that flows up past Greenland and Scotland and is now extending further and further into the Arctic Basin. There is an under sea ridge that traps cold bottom water in the Arctic Basin, since the ice ages began this water has been to a large extent trapped and stagnant. The 500 mb level is IIRC where the Jet Stream, both Tropical and Polar, are formed. It refers to the altitude in the atmosphere where that air pressure level is reached. If I got that wrong someone will stomp on me pretty quick. The Jet Streams form where the three cells of each polar hemisphere come in contact, the Polar Jet is where the Polar Cell and Ferrel cell collide and the Tropical jet is formed where the Ferrell Cell and Hadley Cell collide.

I believe the ridging he is referring too is the way the jet stream is being distorted north and south from its expected west to east track.

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