Eleven Days in Pacific Arctic are shown in the above animation.  In the upper center, Chukchi finally froze completely, adding 260k km2 of ice to reach 99.8% of maximum.  (Disregard the blue jagged arc as a sensor artifact.)  Meanwhile, serious freezing began in the two Pacific basins.  Bering to the south of Chukchi went from 57k km2 to 195k, now 43% of maximum.  Okhotsk to the left went from 58k km2 to 223k, now 19% of maximum.

The graph below shows December progress in ice extent recovery.

From days 335 to 339, 2018 extents were flat and went below average.  Now freezing has resumed as shown in the animation above and tracking close to average again in the graph.  At day 349 (Dec. 15) MASIE shows 2018 1 day behind average (100k km2),  200k km2 greater than SII 2018,  140k km2 greater than 2007 and 358k km2 more than 2016.

The central Arctic and Eurasian shelf seas are completely frozen, typical for this time of year.  The Pacific was a little slower than usual to start, but is now coming on strong.  The Canadian side froze early and is of course locked in for the winter.  The only remaining deficit of note is Barents Sea which hasn’t added ice in the last two weeks.

Seventeen Days in Hudson Bay are shown in the above animation.  In the lower center, Hudson Bay pushed its ice extent up to 1.24M km2, 98% of maximum.  Just to the northeast, Hudson Strait and Ungava Bay are completely frozen over, with Baffin Bay reaching down.  At the top left you can see Chukchi Sea growing ice toward Bering Strait.

The graph below shows recent progress in ice extent recovery.

From days 330 to 339, 2018 extents were flat and went below average.  Now freezing has resumed as shown in the animation above and nearing average again in the graph.  At day 342 (Dec. 8) 2018 is 540k km2 greater than 2007 and 400k km2 more than 2016.

The table below shows the distribution of ice in the various Arctic basins.

The table shows how early is the freezing in Hudson Bay nearly offsetting slower ice buildup in Bering and Barents Seas.  It appears that the Pacific ice extents in Bering and Okhotsk Seas may again be slower than average this year.  The deficits there match the overall 2018 deficit to average.

Eighteen Days in Hudson Bay are shown in the above animation.  In the lower center, Hudson Bay more than doubled its ice extent up to 1.07M km2, 85% of maximum.  Just to the northeast, Hudson Strait and Ungava Bay are almost frozen over, with Baffin Bay reaching down.  At the top right you can see Greenland Sea ice reaching out toward Iceland.

The remarkable growth of Arctic ice extent in November 2018 overcame the October deficit,  went 400k km2 over the 11 year average and exceeded all but one year in the last decade. The graph below compares the last 12 November ice extents.

The monthly average of all November days shows 2018 matching the 11 year average, slightly higher than 2007, and 1M km2 greater than 2016.  The graph below shows the daily growth of ice extents throughout November, on average and for some important years.

2018 ice growth slowed so that it only slightly exceeded the 11 year average at month end.  At 11.15M km2, it was higher than other recent years, 1M km2 greater than 2016.

Dr. Judah Cohen at AER  posted on Dec. 3 explaining the November dynamics.  Excerpts in italics with my bolds.

Figure i. Observed surface temperature anomalies 1-29 November 2019.

In the month of November there were two distinct pulses of vertical energy transfer from the troposphere to the stratosphere that resulted in a perturbation of the stratospheric PV and a displacement of the PV towards Eurasia with an elongation towards eastern North America and a warming centered near Alaska and Northwestern Canada. However, those pulses were not simply absorbed by the polar stratosphere but in large part ricocheted or reflected off the stratospheric PV and back into the troposphere. So that in large part forced a similar pattern in the troposphere that it did in the stratosphere. The vertical energy transfer and the subsequent boomerang back down creating a similar pattern in both the stratosphere in troposphere happens very quickly over a matter of days. The tropospheric pattern of ridging near Alaska and western Canada with troughing in eastern North America and the northerly flow between the two atmospheric features delivered a relatively cold November to Eastern Canada and the Eastern US (see Figure i).

But now we have a new month and still more active vertical energy transfer as indicated by the red shading in Figure 11. For the first half of December there are predicted two or three distinct vertical energy pulses. But what is missing so far for the month of December is any blue shading, these waves are not being reflected or ricocheting off the stratospheric PV but are almost completely being absorbed in the stratosphere. This wave energy should therefore have a bigger and more lasting impact on the stratospheric PV. From Figure 10 we can already see hints of this. For the first time this fall and now winter 2018/2019 the polar cap heights are predicted to be above normal in the middle stratosphere. But my expectation is that this latest perturbation of the stratospheric PV will be evolving for weeks and not days and the peak will likely occur either in late December or early January. Also the eventual impact on the troposphere will be weeks and not days.

But because there is no reflecting or returning signal from the stratosphere what is dominating the troposphere is the thermal advection or the migration of air masses across the NH. As I discussed last week and again today this transport of heat is usually characterized by a cold East Asia and western North America and a mild eastern North America and if you look at Figures 3, 6 and 8 this is generally the temperature pattern that is being predicted over the next two weeks with the focus of the cold across Siberia, East Asia and Alaska. Eastern North America is predicted to turn much milder starting next week. I am not as sure what is the impact for Europe during active vertical energy transfer and I thought maybe mild but the forecast for Europe is vacillating between mild and cold but turning milder across Northern Europe.

Meanwhile, in Nunavut, it is a great time to be a polar bear, even more of them than people want.

The remarkable growth of Arctic ice extent continues with a new development yesterday, as shown by the graph below.

Note that as of day 330, Nov. 26, 2018, Arctic ice extent exceeds the 11 year average reached at month end.  At 11.08M km2, it is 400k km2 above the average for day 330.  It also matches 2013 (not shown) with only 2014 slightly higher in the last decade.

Dr. Judah Cohen at AER posted yesterday on the difficulties forecasting this winter’s coming months.  Excerpts in italics with my bolds.

In my opinion troposphere-stratosphere coupling is now in full gear and is having a significant impact on the large-scale circulation of the atmosphere. The relatively active vertical transfer of energy from the troposphere to the stratosphere is repeatedly perturbing the stratospheric PV though it is not of sufficient magnitude to force a significant PV disruption but only minor disruptions. Still the stratospheric PV is predicted to be continuously displaced from the North Pole towards northwest Eurasia. The displacement of the stratospheric PV south of its normal position is allowing the stratospheric PV to grab milder temperatures from more southern latitudes and sling shot it from across Asia towards Eastern Siberia and Alaska, where the warming temperatures are building ridging/positive geopotential height anomalies in the stratosphere centered near Alaska. This is resulting in northerly flow between the Alaskan ridge and stratospheric PV on the North Atlantic side of the Arctic from central Siberia to eastern North America. We have seen the same flow already mimicked or repeated in the troposphere during the month of November contributing to an overall cold month of November in the Eastern US.

As far as the winter as a whole, I believe that the behavior of the stratospheric PV is critical. The vertical atmospheric energy transfer looks active to me for the foreseeable future. This could lead to a significant or major stratospheric PV as early as the second half of December and extending into early January. If a large stratospheric PV disruption were to occur in the late December and early January timeframe this would be almost ideal in contributing to an overall cold winter for the usual favored regions across the NH mid-latitudes, but each event is unique. Any delay in a significant stratospheric PV disruption would lead to an extended period of volatile weather and increase the odds for an overall mild winter especially if the stratospheric PV strengthens and becomes circular in shape. There is the scenario where the vertical energy transfer remains active, the stratospheric PV is perturbed but no significant disruptions occur and the Eastern US still experiences a cold winter ala winter 2013/14 and is described in our new paper: Kretschmer et al. 2018, but more on the paper in a future blog.

Meanwhile, in Nunavut, it is a great time to be a polar bear, even more of them than people want.

The title of this post is over the top, but was provoked by the repeated claims last summer earth was going to hell right now.  For example,

The world’s summer of hell.  Hot, hot, hot: Summer of extremes setting heat records around the world, July 2018, CBC

Summer 2018: On the highway to hell? August 2018, Beyond Ratings

Earth at risk of becoming ‘hothouse’ if tipping point reached, if we can’t stop it we’re in a hell of a mess..August 2018, CNN

The Summer of Hell.  Climate change is here and we are living in its embers.  August 2018 The Week (US)

Meanwhile, back in reality, Arctic ice is spreading everywhere.  The image below shows the European side in the last two weeks:

Laptev and East Siberian in the middle are frozen solid. On the right Kara has added 400k km2 ice extent up to 700k km2, 75% of March maximum.  Below is the freezing proceeding on the Canadian side.

Baffin Bay in the center next to Greenland is extending south and added 300k km2.  Hudson Bay on the left added 400k km2, with the western coastline freezing all the way down into James Bay.  The graph below shows 2018 is matching the 11-year average after being down in October.

Both MASIE and SII have 9.9M km2 ice extents matching the average for day 320, Nov. 16.  2007, 2012 and 2017 all recovered from their September lows, while 2016 was much slower to refreeze.

Deficits in Chukchi, Greenland and Barents Seas are offset by surpluses in Kara Sea, Baffin and Hudson Bays.

Meanwhile, in Nunavut, it is a great time to be a polar bear, even more of them than people want.

When Hell Freezes Over (Eagles Reunion Tour)

Russian Coastline Freezes in last Ten days

With the Canadian Arctic already frozen over, the action has moved to the Russian side.  The image above shows East Siberian and Laptev basins filling in completely.  Meanwhile on the right Kara Sea has gone from open water to nearly half of last March maximum.  Kara went from 114k km2 on day 298 to 435k km2 yesterday, 47% of March max.

The graph shows MASIE reporting ice extents totaling 9.0M km2 yesterday,  matching the 11 year average (2007 to 2017 inclusive).  Notice that 2018 lagged the average by 900k km2 on day 296 and overcame that gap in 13 days.  Presently, 2018 is tracking  300k km2 above 2007, 600k km2 more than 2012, and  1.3M km2 more than 2016. NOAA’s Sea Ice Index continutes to match MASIE through this period.

The current IMS Snow and Ice Chart shows how snow is covering Siberia completely, and has spread over northern and eastern canada.  Snow cover is an important indicator for the coming Arctic and NH winter, as explained by Dr. Judah Cohen in his latest AER arctic oscillation update (here).  Excerpts in italics with my bolds.

What unfolds next with the stratospheric PV (Polar Vortex) and troposphere-stratosphere coupling could be critical for determining the average temperature for the winter (December-January-February). Currently the GFS is predicting that the vertical transfer of energy from the troposphere to the stratosphere will become relatively quiet after this week. This will allow the stratospheric PV to recover and strengthen the second half of November. If the stratospheric PV becomes relatively strong and circular in shape in early December and couples to the mid and lower troposphere, this will likely result in a mild to extremely mild pattern across much of the NH including the Eastern US and northern Eurasia. At least for the Eastern US, it will be very difficult to recover from a mild start to winter and the winter temperatures would likely average mild regardless of what transpired the remainder of winter. Across northern Eurasia including Europe I think the outcome is a little more in doubt, as we saw last winter, Northern Eurasia and Europe can still average below normal for winter even with a mild start.

However an alternate path is that the energy pulse predicted for this week is not unique but is followed by subsequent pulses that further perturb the stratospheric PV. I see no evidence of this from the latest GFS forecasts, however in my opinion the NH tropospheric circulation remains favorable for subsequent PV disruptions. I think the place to watch is Siberia. As long as Siberia remains cold further energy pulses are likely with disruption to the stratospheric PV. However if Siberia turns mild for an extended period then we should expect a relatively strong PV for at least several weeks.

I would also like to note several trends. Snow cover extent remains above normal across North America. I do believe that snow cover can foreshadow the weather and the early season cold air outbreak across Eastern North America was at least preconditioned by the extensive snow cover for the entire fall this year. As long as the snow cover remains extensive and resilient, eastern North America remains at risk for subsequent cold air or Arctic outbreaks. However in the near term snow cover advance has been most impressive across Asia and with the more extensive snow cover, cold air is building across Siberia and is predicted to become more widespread. And just as I discussed above how long the snow and cold persist across Asia could be critical for the character of the winter not just locally but even remotely including the Eastern US.