Vanishing Polar Vortices

January 20 2017,  700 mb temperature measurements captured a cold mid sized Arctic Polar Vortex with 3 vortices,  the larger yellow line expanse is -20 C isotherm,  within are significant colder vortices having temperatures lesser than -30 C,  at their center are CTNP's (Cold Temperature North Poles),  all with winds turning counter clockwise around them.    We note Alaska and near North of URALS Russia, having one,  very unlike 2018 winter to date.

January 16 2018,  A very different scene indeed,  Urals and Alaska were much warmer, not only on same yearly days  but throughout the winter to date.  We notice the Russian Vortice CTNP being coldest in the World,  but it was not always so.  It has been rebuilt from a devastating North Pacific Cyclonic merge,  at one time there was no significant vortex on that side,  a few weeks back with Upper Air temperatures exceedingly warmer.   These are the times when vortices regularly disappear in the Arctic from warm Cyclonic Northward incursions,  particularly driven North by smaller  in size vortices  .  

Notice the Canadian side Vortice in the process of vanishing,  Ellesmere Island being warmer than Disko Island Greenland,  quite astounding.   

   

  January 17 2018,  we note the Russian vortice stable and cooling a bit.  But the Canadian Arctic Archipelago vortice receiving a final literal blow of warm air coming from the North!   An amazing feature,  this of course changes weather patterns throughout North America.  WD January 21,2018

T***<=Ts duplicated in a Southern location with special instrumentation

Congratulations and salutations to:

C. L. Pérez Díaz , T. Lakhankar , P. Romanov , J. Muñoz , R. Khanbilvardi, and Y. Yu

who wrote and published:

Near–surface air temperature and snowskin temperature comparison fromCREST-SAFE station data with MODISland surface temperature data

~Although not looking for a Skin snow temperature (T***) vs Surface air  (Ts) relation, a very significant paper measured it with great precision using different instrumentation.  At Caribou, Maine USA (46◦ 520 5900 N, 68◦ 010 0700 W)

~ Instruments  : "An Apogee Infrared Radiometer is used to measure snow skin temperature directly by converting thermal energy radiated from the surface in its field-of-view (FOV) to an electrical signal with a response time of less than 1 s (Muñoz, 2014). This process is automated at every 3 min to an accuracy of 0.2 ◦C. The air temperature is measured directly by a Vaisala Temperature/RH Probe through an automated process; also at a 3 min sampling interval with the same accuracy"

      The results from this effort are very important to study:

Caribou Station equipment extraordinary capacity to measure snow surface skin temperatures with accuracy even with the presence of the sun probably offers the proper way to re-equip  mass balance sea ice buoys. 

As we can see,  T***<=Ts ,  snow skin temperature seems indeed always colder than Surface air temperatures even with hourly measurements.  This has been observed optically either over land thoroughly covered by snow or especially at the Arctic Ocean horizon.  The effects of winds, tend to reduce near refraction as well.,  but not always, this has been a subject of great interest.   

Here are a few very important observations and conclusions from the authors (in Italics):

~"Results indicate that near-surface air temperature correlates better than snow skin temperature with MODIS LST data"

   I have found that so, in particular if NOAA daily climate composites uses MODIS as their data source.  I established that we can detect a satellite error by using said simple formula T***<=Ts.
 
~"This leads to the suspicion that maybe ground-measured LSTs in high-latitude regions covered in  snow might not display congruent behavior with satellite readings. Because if the snow temperature satellite readings are far from the real values, this can lead to confusion when trying to predict the occurrence of avalanches or spring floods."

    Suspicion confirmed,  particularly in the Arctic,  this was frequently observed while comparing NOAA daily composites,  while they had skin temperature option available,  a significant problem here, recognized by the authors,  are irregular surface features,  either not covered by snow completely or affected by high vegetation,  trees for instance.

~Near-surface air temperature tends to affect the snow skin temperature directly, although the latter’s fluctuations are not as drastic (Walsh et al., 1985). The record shows that the winter of 2013 was the coldest of the two (hourly lows of −26 and −36 ◦C in late January for T -air and T -skin, respectively). However, it cannot be ruled out that it is possible for the near surface air temperature to be colder than the snow skin temperature at particular times throughout some winter days, but not common on a daily average basis."

    While using much simpler instrumentation and a different technique altogether,  the latter assumption:  "However, it cannot be ruled out that it is possible for the near surface air temperature to be colder than the snow skin temperature at particular times throughout some winter days",
has never been measured with more primitive method, unless the ground surface has a mix configuration of snow and exposed land,  similar to sea ice mix with open water,  which gives a different horizon height."Near-surface air temperature tends to affect the snow skin temperature directly, although the latter’s fluctuations are not as drastic" ,  this has not been observed here in the High Arctic, surface temperatures  and skin temperatures vary in tandem almost if not instantly, sometimes skin temperatures vary independently while surface temperatures do not and vice-versa.  If the authors rather implied that very near the skin of snow air temperatures may be colder than top of snow,  I do not believe so,  but the temperatures can be equal.

Self published related articles:

http://eh2r.blogspot.ca/2017/12/ts-ts-is-probably-greatest-winter.html
http://eh2r.blogspot.ca/2017/03/consequential-application-of-first-rule.html
http://eh2r.blogspot.ca/2017/03/first-rule-of-sea-ice-horizon.html
http://eh2r.blogspot.ca/2017/02/summer-greater-cloudiness-thermal-flux.html
http://eh2r.blogspot.ca/2016/06/the-models-may-be-calculating-sea-ice.html
http://eh2r.blogspot.com/2016/05/optically-unlikely-not-possible-remote.html
http://eh2r.blogspot.com/2016/05/remote-sensing-vs-refraction-prime-sea.html
http://eh2r.blogspot.com/2016/04/sea-ice-refraction-prime-rule-top-of_28.html
http://eh2r.blogspot.com/2016/04/sea-ice-refraction-prime-rule-top-of_28.html
http://eh2r.blogspot.com/2015/05/dedicated-sea-ice-model-proofing.html
http://eh2r.blogspot.com/2014/04/sea-ice-thermal-balance-appears-to-be.html
http://eh2r.blogspot.ca/2014/06/from-optical-based-hypothesis-to-reality.html
http://eh2r.blogspot.com/2014/06/hrpt-skin-temperature-muddle.html
http://eh2r.blogspot.com/2013/05/sea-ice-phase-change-from-underside.html
http://eh2r.blogspot.com/2013/04/data-gathered-from-optical-refraction.html
WD January 9, 2018

Direct Causal link between ENSO index and Snow extent version 2017-2018

~ Winter Northern Hemisphere Cloud seed theory is :  During El-Nino or especially trending El-Nino more snow,   During La-Nina or especially trending La-Nina less snow

~ It is ecstatic to discover how small this planet is. 


  Proof you ask?

None better than show the facts:

  We note this table from most expansive break down on current ENSO expose (must read here),
look at 2016 brief continuation of El-Nino especially during winter.  Then a downturn to La-Nina from June onwards with a pause in trending during winter 2016-17,  which had significant implications in many parts of the world, then back to trending La-Nina end of 2017.  It means that the trending part is a or the most important aspect.  ENSO reached LA-Nina during the summer of 2016 (when only there is a very small snow signal possible) , however spring 2017 had small upward warming,  which meant more clouds,  which in retrospect affected the entire spring summer season.  And now perhaps the real La-Nina backlash from strong 2014-2016 El-Nino will really show up. 


    So basically if we use the said theory,  there would be more snow in 2016-17 than 2017-18,  lets look

Beginning of winter 2016-17 in light green had indeed  more snow on the ground,   2017-2018 less .   I believe the same can be said with previous winters,  except this graph (taken here) etchings are hard to distinguish.  2011-2012 appears to be lowest which makes sense.  Note the breaking to less snow extent trend starting November 2017 mimicked identically with ONI cooling in table seen just above.  Finally, late winter 2015-16 (I colored matched the outlying lone lowest snow extent in March) had very significant drop in extent , from very high to lowest, exactly when 14-16 El-Nino was ending and substantially trending La-Nina .  WD January 4 2018.

Winter 2017-2018 smaller Arctic Polar Vortex Vortices make it warmer for most places except one colder area at once

~The smaller and colder the CTNP vortices the more unstable they become.
~Moving Southwards cold vortices are not a sign of cooling, quite the opposite,  they are
symptoms of a warmer world.
~We now have a climate system which makes modest cyclones very important  in rearranging
   Global Circulations within a few days.

World News flash! it is only colder in about 2/3 of North America at present:

NOAA temperature anomalies are not exactly announcing the beginning of a new ice age,  but if you live in North America you might think otherwise.  Note East of the Rockies coldest surface temps,  not exactly unexpected as written in previous article,  the lack of snow on the ground at midwinter is very conducive for a deeper cooling.  The good news is ,  a significant area of colder atmosphere is not necessarily stable,  and can move away or fade rapidly in especially a warming world:

 Note the Polar Vortex is the entire counterclockwise circulation starting in orange Northwards,  which has cold air vortices within:

NOAA daily composites at 600 mb,  this is where the temperature represents the entire Troposphere.  We see in deeper purple the coldest atmospheres which morph quite a lot,  it gets disrupted by mainly wrm air advection fom moving Northwards Cyclones.  It is not quite exactly a world wide cold winter.



Slowing down the previous animation you can read why a warmer planet has unstable less pervasive colder air ,  but can have serious events of deep freezing even though the rest of the world does not: 

Currently only North America has a deep surface freeze,  this can change quickly,
the smaller the coldest atmosphere (with respect to the size of the rest of the world) the faster its change in spacial distribution and the greater the temperature extreme variances. But this year has 2 main coldest vortices which tend to reform.  Reminds me of hurricane eye wall replacemens.
They are  Canadian Arctic Archipelago and NE Siberia,  both are vulnerable to small weather events, morph rather quickly,  distort along the warm air zones given by the Atlantic and Pacific.  Central Russia and Alaska have had most fascinating warming because there is not enough winter to spread around.  WD January 3,2018
  

Winter's coldest thermal machine, almost bare ground in darkness

~When a thick snow layer becomes a thermal insulator roof for ground heat

~We explore the 2 current Cold Temperature North Poles of the Northern Hemisphere


   Presently there are 2 CTNP's in the Northern Hemisphere both rated almost as cold as each other:

     The nearly pervasive CTNP's of this cold season,  the CAA (Canadian Arctic Archipelago) and Northeast Siberia.  Taken from CMC 700 mb map 22/0000 UTC this winter solstice day.  Have had an early winter link with extensive snow layerings ,  now in darkness this link is broken,   Arctic locations with less of a snow have become the spawners of extreme cold temperatures:

  We know from a previous article (here),  that snow cover may not exactly be pin pointed correctly,  however the Baker Lake Kiwatin area  has a neat center of more bare land,  source Eisbedeckung und Schneehoehe from Wetterzentrale Dec 22 2017 0600 UTC.   Alaska seems to have a lot of snow, a likely reason for why winter is not becoming one massive Arctic block.  We note with interest Alberta which should be prone to massive cooling given that it is a corridor of no snow.  But here just West of the sea of Okhotsk East Siberia Russia has a similar land based snow lacuna.  Both relatively left unperturbed by weather events are great areas to cool the Northern world further in these highly localized geographies with hardly a sun to warm them.  As we have learned, the cooler the CTNP the more "attractive" it becomes to Cyclones.   They become unstable by their strength,  but come back once perturbed by weather  bondings which can't last due to the very nature of dark rapid cooling in these polar zones. WD Dec 22,2017

   
   

T***<= Ts is probably the greatest winter equation

~Extremely simple to express another matter to explain mathematically.

~Down past the skin, snow layers thermal profiles literally change with weather

~ One can estimate sky conditions by the thermal profile of  a snow drift

         Going back to the Horizon refraction discovery of a few years ago:

                                          Tice<=Ts 


              Tice<= Ts,   which has never been disproved optically,  but never been measured physically except from sea ice buoys during the sunless long nights.   The temperature on top of sea ice (including snow)  is always colder of equal to surface temperature,  this discovery,  prompted the question about snow on top of land,  is it the same?


     After many thousand observations with measurements,  T***<= Ts (***= top of snow layer) was very very elusive to measure,  the first problem was sunlight,  some of my readers know ,   sunlight induces a temperature error to all surfaces with a snow layer.  There are no easy,  readily observable  temperature readings with relatively inexpensive instruments.  Temperature stratas in a column of snow  vary with weather,  which is amazing.   On many occasions, optical observations suggested T***=Ts   the top of snow temperature did not confirm so,  when optical observation interpretation  had an obvious inversion,  the snow was warmer than air.   Even in the thick of winter, when everything is more refracted,  snow readings denied what was seen,  in great conflict with horizon sea ice observations.

   Turns out it was the measurement method,  and the crucial understanding which is that snow temperature columns vary in tandem to weather ,  which broke the mystery. 

    What does this mean?

     In particular,  it is the build up formula for winter on planet Earth,    albedo up to 90% renders sunlight heat practically irrelevant,  but winter comes from  a dark world,  where  the sun is forgotten only reminisced by a faint twilight.    It is in this star lit world,  where winter becomes fierce or faint.    If winter starts earlier,  it can only be by pervasive dark moisture rich clouds, which imprints a snow carpet,  nullifying any warming by whatever sunlight gets through.    In the days of anthropogenic enhanced Global Warming,  this frozen moisture should be greater,  therefore more snow should be expected,  as it does happen yearly  more often than not,



"As sea ice shrinks, the Arctic becomes warmer and wetter, study finds8 / 2015 - Present


http://www.adn.com/article/20150809/sea-ice-shrinks-arctic-gets-warmer-and-wetter-study-fi November saw the biggest increases in “skin temperature” (defined as temperature at the Earth’s surface), and air temperature, with an average annual rise of 0.42 degrees Celsius on the surface and 0.32 degrees Celsius in the air, said the study, by Linette Boisvert of the NASA-affiliated Earth System Science Interdisciplinary Center at the University of Maryland."


 except for when major climate event,  such as from ENSO which changes cloud formations.   I recall in the fall of 1998,  a lack of High Arctic snow carpet was ever present:

      EL-Nino creates low stratospheric cloud seeds, which propagate easily throughout the world.  1998 was then the warmest year in history because of an unusualy strong El-Nino,  warmest despite a rapid change to La-Nina within the same year. (as with this October 16 NOAA SST chart) .  The Canadian High Arctic fall in 98 was sunny with hardly any snow on ground as late as early November, with Barrow Strait freezing the latest in 20 years.    ENSO had a long distance impact.  Just like in 2016,   but in 16,  the Arctic fall had more snow because  La-Nina spring trending brutally stopped during summer.   2017 late spring ENSO had an upsurge towards warming,  then now fast trending to La-Nina (with lesser clouds being created worldwide),  therefore less snow on the ground than with autumn 2016 as it is at present.    This late in the year less clouds trending has huge winter implications,  particularly where there is less snow than normal.

     The question is what happens when land areas exceed snow in pure darkness.  The answer is faster cooling tempered by snow cover .   Land surfaces are pretty much like water when it comes to snow or sea ice.    In summer Arctic sea surface water is a near constant in temperature varying quite slowly one day to the next.    In winter, top of permafrost becomes land surface,  a constant which varies at a wider range than surface sea water temperature though,  but varies day to day in similar ways to sea surface.  Depth is key,  in very early winter top of land is very much like open water,  the optical readings suggest warmer land surface than surface temperatures:


                                                                          T *  >Ts   from a sun radiation
                                                     or equality in temperatures morning and evening:

                                                   T * = Ts with low to mid level clouds:
                                                      or         surface cooling at night:  
                                                   T * <  Ts 

            T * is like a snowflake in a wide field,  like a bergy bit in wide open water,  the predominance of land or water is nearly oblivious with scarce presence of snow.    Ts is part and parcel of the air to surface complex, if the surface changes Ts does likewise, a bit of snow on wide land approaches the nature of no snow at all, in darkness or sunshine,  but it can still affect the surface temperature as it can still be measured optically   Then when snow starts to cover the surface more completely , the horizon shifts  to more neutral heights

                                                                          T* * --> = <--  Ts  nearing 50% snow cover tends to make equality in temperatures

          T* * is  near 50 50 area cover snow when  we can literally judge whether the area of snow exceeds land cover or is less than, made more complex  by land temperature differing from top of snow temperature,  if land gains more exposure when warmer than snow,  the horizon drops (the reverse applies).     These small variations are only applicable till cold really sets in especially on top of ground.  When snow carpet approaches 100%,  the optics are all inclined to behave like if snow is the only thing which matters. 

          Then the easiest equation expressing a physical dominance of snow is T*** <= Ts,,  with near or complete snow cover ,  even with sunshine and during Midwinter darkness T***<= Ts,  even during a cooling atmosphere event,  however when low or mid level clouds overcast the sky T***=Ts in all other circumstances T*** is  colder than Ts.


         
                     
 
                       

CAA returns to prime cold spot despite massive prolonged warm advection event

~The return to Cold Center of the Northern world stems from very complex geophysics

~ CAA had short term very warm atmosphere,  remnants of this warming exists but fall as snowflakes.

~Deeply cold but regionally small CTNP's are unstable by the mere presence of  moderate cyclones. 

600 mb temperature charts of November 20-24 December 2- 3 2017,   NOAA daily composites. They depict an astounding warming of the CAA atmosphere peaking on  about November 24.,  note how fast it went from coldest to hardly an existing cold cell.     600 mb temperatures are very close to the Density Weighted  Temperature of the entire troposphere.    Even more fascinating, even when expected,  was the return on December 3 of Canadian Arctic Archipelago  to coldest DWT,  again it is the Cold Temperature North Pole.   How do we explain this?  It is complex because land skin temperatures vary from snow coverage not uniform at all everywhere.  The quick warming of the CAA demonstrated  its canopy of mixed conditions,  with likely not so much snow on the ground,  the top permafrost and snow cover warmed rapidly.  When the Mega blizzard advection event ceased,    it snowed a lot more than previous recent weeks,  this covered the warmed top landscape slowing the cooling.  But cooling did occur nevertheless,  by radiative cooling of top of snow and slowed sublimation,  because of fresh flaky snow fall  relative humidity remained high diminishing  the sublimation rate.  

     But the atmosphere cooled faster aloft,  mainly oblivious to low clouds,  in other words, 

the clouds cut off heat to the upper mid atmosphere,  enabling its rapid cooling.   Which inevitably exacerbated the cloudiness and extra snow precipitation,  by stronger convection of lower warmer atmosphere.  

     Even though the Northern Hemisphere had one coldest cell over Eastern Siberia (November 24) and the warming event was about 10 days long,  the Jet Stream didn't change that much in position,  because 10 days is apparently not enough to cause major Jet Stream deviations causing disruptive weather or Global Circulation changes.

     Now is the time when little covered or bare Arctic lands start the mega-cooling process,  excess snow cover cooled  some Arctic autumn locations,  this insulation carpet now changes roles  to save the Arctic from extreme deeper freezing.     Areas with very little snow cover will now on start to change the nature of CTNP's,  from 2 current strong ones to a third or fourth  smaller ones.    We look for them around the Urals and Alaska.  Meanwhile CAA cooling along with NE Siberia will undulate the Jet Stream worldwide  WD December 6 2017

Remote sensing snow cover appears to be not measured accurately

~ It is perhaps a great technical fundamental flaw which disables accurate long term forecasting

~ New refraction technique suggests that snow on ground behaves exactly as on sea ice which is :
Top of  wide span 100% snow layer T*** is always colder or equal than surface Temperature   
                                                                T***<=Ts
       (A snow layer is not freshly fallen snow,  it is a layer on ground more than several days old) 

~ Taken on a wider Global scale we can identify where the areas with most snow cover lay.

None of these Remote sensing current maps are similar in any great way.   We have N18 (Dec 1) which is NOAA,  the German one Wetterzentrale (Dec 2) and Canadian CMC (Dec 1).     CMC has central Quebec with a lot of Snow,  unlike Wetterzentrale  which has a lot of snow on its Eastern side and NOAA looking completely foreign to the 2 others with more but less significant snow cover in Nunavik (Northern Quebec).    Wetterzentrale has a lot of snow in Russian Urals NOAA doesn't at all.  NOAA has a vast layer of expansive thick snow in North central Siberia unlike Wetterzentrale which has a thick snow carpet in NE Siberia.    CMC has a lot of snow in central or the Alaskan interior  unlike Wetterzentrale more like NOAA.    It is hard to make out CMC's Canadian Arctic Archipelago snow cover because of numerous Glaciers on its Eastern side.    NOAA has Canadian boreal forest tree line gap of less snow unlike the other 2 maps.

Confused?    Just where are the areas with most snow cover?   If we go by a simple gathered by optical refraction rule:

                                                                       T***<=Ts

           It means that all places with important thick cover will be cooler than normal,  because the sun,  although weaker by low elevation,  would warm the ground more if bare, which was heated up by the summer.  So we look for places with cooler temperature anomalies,  given that even with warm or cold air advection,  time will bring out the cooler locations:

       Last 30 days NOAA reanalysis suggests Wetterzentrale  correct for Northeastern Siberia and NOAA incorrect about the snow gap of the Northernmost tree line (there should be more snow not less there).    However there was a huge anomalous advection of warm air throughout the CAA,  as reported on previous article below.   We must go prior to November 22 to get a better picture:

   NOAA temperature anomaly October 22-November 22 .   We can note the CAA appears cooler before the warm air advection,    the cold was indeed in Northeastern Siberia and the Canadian tree line,  suggesting that these lands are laced with thick snow layer.    But there was a normal CAA cooling despite greater open water:

  The tree line bit was not as cold as NE Siberia and the CAA which prior to November 22 was the coldest place on Earth.   There was early snow over much of the CAA which sublimated and gradually diminished in thickness before the Arctic mega blizzard.    In conclusion ,  there is a lot of snow Northeastern Siberia,  but need to confirm the tree line bit.  December 3, 2017

Global Circulation flipped by mega blizzard with no wind directions change for a week at 40 to 50 knots.

~CAA  Cold Temperature North Pole captured a Low otherwise on its way to NW Europe
~The dynamics were similar to  heat machine fueled by the temperatures contrast between  warm and cold, open Oceans and a frozen Arctic scape.

    A remarkable blizzard spanning a great deal of the Northeastern Canadian  Arctic essentially made winds  coming from a rock steady direction for weeks.    Record temperatures warmed all of the Canadian Arctic Archipelago for the same time period,  heat injected from the oceans displaced and weakened and moved the CAA Cold Temperature North Pole,  which had garnished cooling for months,  further to the South and West in a matter of days.   What happened was a matter of weather dynamics which forced two main geophysical opposites,  warm and cold atmospheres in a fused static stalemate:

From 18th to 24 November this CMC 22 November surface analysis is the picture of the blizzard week.  A perfect,  stuck in place,  heat engine with heat from the East open sea waters meeting the coldest air in the Northern world head on.     At first,  the center of cold was  steady strong over the center CAA:

The main dominant cold air zone of the Northern Hemisphere had a weaker twin Northeastern Siberia,  in between  huge strong anticyclone,  which given the right conditions,  can push the strong CAA CTNP  southwestwards.  The arrival of a low pressure centered about Hudson Bay was just what was needed.  And so the biggest pan Canadian Arctic mega blizzard of 2017 happened with a trowal which lasted as long as the Hudson Bay Low persisted.    As  a result ,  record warming reigned throughout the Canadian high Arctic .      This Low didn't move for a week along with static wind directions everywhere. 

     Global weather circulation was thus changed  in a few days,  making Northeastern Siberia coldest atmosphere at present.  But this is changing quickly,  as the CAA permafrost was seriously cooled prior to this warm air advection, which means that the CTNP will soon return to dominate on the Canadian side of the Pole.wd November 25,2017

Winter 2017-2018 is definitely taking shape.

~ New state of the art refraction technique confirms Canadian Archipelago atmosphere set to dominate Global Circulation.

~Each winter is unique,  2017-18 is set to be dry in most parts.  With normal cold and abnormal warming in about equal distributions.

~ The mystery of the warming Russian Northern Urals.

   Elegance in darkness, winter rises from frozen grounds,  left without snow it starts later,  laced with a thick layer it seems to manifest weeks earlier.  The larger question to ask is whether  deeper earlier snow brings the bitter coldest winter.

   If we look at current data,  compare to winter 2016-17,  the answer to that question is a likely NO:

 Air areas marked in brown are Cold Temperature North Poles (CTNP's),  2  of them,   one over the CAA the other hovering NE Siberia.   Winter 2016-2017 main Arctic feature was the extreme North Atlantic snow dump from Atlantic Cyclones heading strait towards Russian Urals.  This meant a greater injection of moisture  towards Northern Greenland and central CAA (Canadian Arctic Archipelago).   As a result there was a double the normal layering snow carpet.  This prompted an earlier onset of CAA winter,  but over the long run reduced ground surface cooling.

 Current state of the art land refraction observations tend to agree that the beginning of winter 2017-18 is substantially colder over the CAA because of the relation of earlier more snow on ground blocking the heat which would come from a warmed by summer permafrost :

   Early 2017-18 winter has a major circulation change which affects most of the Northern Hemisphere weather.     The CTNP cells have switched roles ,  CAA being colder and bigger than 2016-17.  This is of great interest.   Western North America has cooled,  while Eastern North America has baked to the delight of extended summer lovers.

      As a result,  places like Ottawa Canada,  New England USA,  England UK  and NW Europe
felt the full blast from Gulf of Mexico and South Atlantic heat.

   Temperature anomaly map of NASA GISS  describes beginning of winter 2017-2018  quite well,  the heat injection to Arctic in 2016-17 has slowed,  it is still warmer, but nothing like 2016-2017:

 October 2016-17.   Here we see the effect of the CTNP cells  with a different morphology.   The heat injection towards Northern Central Russia has basically vanished because it was mostly spent feeding the Arctic heat wave.

     So the location or lack thereof of snow on the ground literally steers the Global Circulation.  But that is not a constant relation,  if snow cover starts really early in autumn,  this will generate a cold temperature zone,  the center where warm air gravitates.  If the snowfall stops for a long while,  warmed by summer permafrost will be exposed and this warming source will dull's winter's might.   It may sound off,  but snow sublimates and compacts for the greater part of the long Arctic night world.    If not replenished,  mid winter would warm for a while then the ground frozen hard by exposure with radiation to space would be a source of devastating cold air.   If there is greater snow cap on ground instead,   winter would appear brutal early but much warmer at end,  because the ground didn't loose so much heat,  and would help melt light reflective snow earlier.   A very much similar thing happens on sea ice,  but more radical,  a thicker snow layer on sea ice would make it thinner till sunrise from long night,  compelling melting even faster come late spring.

     At present,  2017-18 seems to tend going towards a very warm Euro-Asian Arctic winter, 
while CAA is coldest,  we observe if the cut off of snow supplied from the North Atlantic by way of the the North Pole continues,  if so,  permafrost will freeze hard,  sea  ice will thicken more,  a very cold CAA CTNP will dominate weather as is for quite some time in the foreseeable future.    Meaning the October 2017 NASA GISS anomaly map may twin or thrice repeat for November and December 2017.  WD November 17, 2017