Friday, April 24, 2020

2020 Annual spring projection, in more details.

~We must remember December 2019 boxing day all time in recorded history low temperature at center of Polar Vortex.   
~As a matter of prognosis,  the  recent overwhelming stable wider area of warming in 24 hour darkness had a side effect,  a smaller area of stable cooling.
~The center of Polar Vortex: the Cold Temperature North Pole will be at the N.P.
~Sun disk observations have shown remarkable early spring warming Northwestwards from center of Canadian Arctic Archipelago,  why is this strange and unusual? 
~2020 Vertical sun disk slight expansion numbers changes past 2 years all time low compressions numbering nil.
~ENSO variations closely resembles vertical sun disk expansion data

Et tu ENSO?

2020 Summer La Nina or El-Nino?   Is the big question.    The usual excellent NOAA updates and analysis suggest a neutral summer again.  There has been very peculiar no La-Nina rebound since very warm 2016 El-Nino.   What we know is that a La-Nina favors dryer air colder winter, as opposed to El-Nino creating more clouds (the cloud seeding theory) giving a cooler summer but warmer winter.   However, the evidence on ENSO variations from afar can be observed.  In the Arctic (and elsewhere) El-Ninos give much higher sliver clouds making spectacular twilights. Again, I observed both types this late winter,  none or few black or white wafer thin high altitude clouds, varying from week to week.  This indeed suggests a Neutral ENSO is coming.  But there is another way to indirectly observe ENSO trends:

NOAA ENSO variations (in colour ) vs Average Vertical sun expansion diameters, from 2002 to 2020.  If one spring year had more average sun disk expansions than others , like super warm El-Nino  2016,   its numbers of maximum sun disks would overwhelm all other years,  as it did (18).  Keep in mind that the NOAA meiv2 time series displays data throughout the years +months and sun disk expansions are measured in the very late winter - early spring.   If you use your mouse you will find that peak vertical sun disk numbers coincide with ENSO trending or being at El-Nino,  for instance 2011-12 trended towards El-Nino,  in all cases except for 2010 to 2011 La-Nina.   What this sun disk graph suggests is that we are trending El-Nino. 

Arctic Particulate de-pollution


  Contrary to popular belief,  our sun is white.  Next to Greenland, impossibly white  to look at with most of its disk under the Horizon.

April 2 2020 

   Note the brilliance of sun lines, not because the camera setting was overexposed.   Horizon colours are of interest, pinkish,  while more brownish in all past recent years.  


  April 2 2015,  same date but 6 minutes earlier than above.  The sun line looks not as colourful,  with a much darker background profile.    There was no Covid-19 Pandemic at the time,  the 2020 horizon appeared lighter, even if most aircraft and many industrial activities were beginning to grind to a halt.    

  2020 Spring sunsets did not occur frequently because NW passage sea ice was often with water skies and distant fog from open water, all caused by significantly thinner sea ice.  

2020 Vertical sun disk diameters,  what's the score?

     In 2016,  of 120 decimal levels , 19 had average vertical sun disks maximums,  making it #1 again,  2018 and 19 were at the bottom of the pack having nil maximas,  2020 has a marked 2020 mini resurgence,  with large vertical sun disks early on the season, not being completely diminished by subsequent measurements.  All was done with at least 500 observations (still on going,  will likely exceed 700) from decimal levels  -0.9 to 10.9 degrees astronomical elevations.  During the last 3 years the center of the Polar Vortex,  the coldest point in the Northern Hemisphere,  was most often very near the middle of  Canadian Arctic Archipelago (CAA).   A slight change has occurred lately.  Usually the start of the season vertical sun disks are measured larger, cold was not set yet, it is usually warmer Southwards as well,  the peak of cold is curiously offset about 1 month or so after the end of the long night.  A true Arctic saying: "it's colder when the sun returns"  has been confirmed again and again.  The scan in elevations gradually changes from South to Northwest,  at winters end, the sun scan is focused Southwards,  as the midnight sun approaches,  the scans veer in directions until 10 degrees sun elevation becomes at midnight local time,  straight North.  Curiously, the peak in disk compressions were usually measured in April and May,  because the sun disks go through Northern CAA air at very long distances ( observing very high in latitude atmosphere just coming out of darkness).    Unlike 2018 and 19,  2020 vertical diameters were not so much diluted as the sunsets veered Northwards.  So far, Northwards sun disks are expanding,  the meaning is simple,  it is warmer towards the Northwest.  Another method of depicting position of the PV center is to look more straight up to the Southwards sun,  2018-19 observations had remarkably compressed  sun disks in April and May towards high elevation sun disks,  above 10 degrees elevation,  to date 2020 demonstrates a warming,  less refraction,  towards the Southern and Northwestern sectors, not compressed like 18-19.   The Southern disk expansions describe a Polar Vortex shifting North,  the Northwestern expansions indicate the Vortex is smaller than 2018-19 or is further towards NE Greenland.  The regular weather maps have long indicated a much more Northwards positioning of the PV center as well.  Care must be considered especially when a cyclone crashes towards PV center,  the PV becomes elongated Southwards,  it usually does not mean,  as sun measurements suggest,  that the PV center has moved.  

Spring Ozone hole sun disk observations

               Extraordinary 2020 spring ozone hole,  even surpassing 1997.  Connected further down in altitude, the Polar Vortex between the troposphere and the stratosphere was in sync especially when the tropopause,  the often high altitude prominent thermal inversion zone between these 2 layers,  became absent.    2020 temperatures at center were in the -80's at about 200 mb heights.  Note,  2019 had faint beginnings of a likewise unified center of vortex on top of the CAA.  2018 had a greater secondary PV center over North Siberia,  winter 2017-18 had a dominant PV start on the center North Russian side of the Pole. 

     2020 ozone depletion reasons for  existing will be studied for years to come,  similarly to 1997's,  which was about 20 % weaker.  

      Sun disk wise,  looking at the higher in altitude sun  in March revealed massive unusual vertical disk compressions.  some .2 to .3 arc minute compressions above 15 degrees altitude,  basically picking up to potentially high impact from a super cold Stratosphere ,  up to 30% of the sun disk size refraction, roughly equal to the Earth's stratospheric pressure contribution.  This extraordinary compression rate dropped to normal,  to about .1 arc minute,  by mid April.  Which again means we were no longer under  a Ozone hole,  or the more unified Polar Vortex has moved or filled as well:

      The vanishing remnants of ozone hole 2020.   

                       Solar Refraction method GT predictions:

       Stemming from these numerous observations,  it is likely that Global Northern Hemisphere temperatures will be at #1.  The smaller hovering Polar Vortex displaced center,  offered a
better look at the truer leanings of Global temperatures,  being at center of the Cold Temperature North Pole in 2018 and 19 made predicting GT's  a factor or 2 more difficult.  It is likely that ease in predicting GT's   from 2004 to 2017  will be a thing of the past because of the persistent last stand of the coldest atmosphere of the northern planet  now often at the CAA .  

                                              Overall predictions

    MAIN EVENT  of summer will persist away from everyone,  the North Pole atmosphere will be the Cold Temperature North Pole,  partially maneuvered by a rare alignment of the stratospheric Polar Vortex.   At present Northwestwards  from central Canadian Arctic Archipelago sun disks are consistently expanding larger by huge factors,  as much as 1 to 2 arc minutes at sun elevations 1 to 4 degrees, even at very high altitudes by .1 to .2 arc minutes ,  this is very unusual  early High Arctic warming,  when there should be none or very little expansions.   The coming N. Pole CTNP does not guarantee a cyclone vertically in sync with it,  but rather more clear Pole weather and cyclones at mid summer CTNP perimeter.    We must not underestimate the reduction in world wide  particulate pollution,  although not guarantied to last given some countries desire kick start their economies, feeling free to be lax on pollutant controls since they have not reached their usual pollution levels at all for months.    But starting up economic systems may start after the sea ice melt season, in early autumn.  The extra bit of solstice solar forcing  power caused by cleaner Arctic Ocean air should break the long standing North Atlantic sea ice front, always a survivor of recent 15 years sea ice melts,  not counting standing record low extent 2012,  so it will be a 2012 type result without the same circulation reasons.  I would expect vast open water from N.P. towards Russia at coming minima,  the Pole having wider open water at a probable 70% chance.  The coming sea ice melt at Mid-September should be below 2012.   

     All the while,  ENSO should morph towards a mild El-Nino,  having for effect of reducing the number of Atlantic hurricanes in favor of the usual strong  number of Pacific Typhoons.  

    The other main event will be well to the South of the North Pole,   the apparent stagnation of weather system movements by mid July.  This means exactly wide regional heat waves over continents,   rudderless hurricanes  ,  along with long stretching  persistent same weather days.  The Further Northward position of CTNP will be expressed by this earlier stagnation , summer CTNP’s  circulation influence only go so far.  Last years brilliant dry summer for most in Eastern North America may be a tad wetter this year given a mild El-Nino.  Important energetic Arctic Cyclones,  similar to 2012 should hit NE Russia onwards to the Pole as well. 

            The North Atlantic High pressure by August end,   a creation from a cooler North Atlantic  made in part by a greater sea ice melt,  teaming up with naturally cooler Greenland ,would be by default the weather maker across both sides of “the pond” .   Not forgetting that what remains of the summer Polar Vortex , however faint,  from its vertical N. Pole alignment, will be slightly stronger than last few summer seasons, will basically cause lots of rain for Western Norway. 

wd April 24-25-26 2020

Tuesday, April 21, 2020

Annual spring-summer-autumn Northern Hemisphere weather projections , by the usual unorthodox methods .... A preview

~8 years since sea ice survived a 2012 summer calamity melt,  the tipping point may be a cleaner atmosphere.
~Sun disk measurement anomalies varied according to   economic slowdowns
~But right before ,  there was further change in circulation,  causing a different snow scape
~The extra sublimation caused by "wet” snow layer insulated the ground and sea ice away from the cooling it caused.
~There is a large question looming whether this noticeable tropospheric cooling  helped the stratospheric “ozone hole” just past. 
~The master of world wide circulation,  the tropospheric Polar Vortex,  has moved Northwards
~Sea ice teetering already at record thin thickness,  will collapse on the Atlantic front. 
~ENSO high cloud symptoms gave varying signals for the 3rd year in a row,  again no plunging towards deep La-Nina is foreseen.  

Here is the preview ,  prognostics and projections will follow on the next article shortly:

   ALFHA sketch ,  it has been discovered that "wet snow" mainly fallen October 2019 ,  remained in a wide area causing extra insulation,  which in turn gave a second  thermal surface,  unique,  likely by keeping the ground or sea ice warmer,  but giving more sublimation, causing by its very properties, more air cooling.  And so was noted a particularly cooler Arctic winter than recent years past.  The location of this different type of snowfall was given here,  largely estimated by the tracks of cyclones, some which gave "southern" in nature snow leaving a track from South of Baffin to the Pole.  This wet snow area will play a large role in breaking down the usual "Atlantic front" ice barrier,  it is very well known thick snow insulation gives thinner sea ice and necessarily more early ice leads.

Figure BETA,  April 20 onwards,  the Cold Temperature North Pole shifted Northwards compared to previous seasons,  as determined by sun disk measurements and other means.  This caused a greater warming of North America since March,  and more rain for Western Europe.   The jet stream in green is at higher latitudes.

GAMMA map,   early switchover is expected well formed about May 15,  late spring cyclone anticyclone positioning start their role reversal, the CTNP will be largely unique.  Early warming of the continents is expected, in part due to lesser pollution world wide, but the dominant reason is the high latitude of the Polar Vortex.

DELTA chart,   June July,  Siberian Highs will be drawn to the Yukon,  the CTNP center of the Vortex will hug the Pole,  therefore more clear weather there,  bad for sea ice,  however around especially multiyear ice along the Canadian archipelago coast,  cloudier cyclone driven weather,  global circulation slower movement for North Atlantic and Pacific cyclones,  reducing moisture
with super warming of the continents,  the North Pacific SST warming is not too strong by slower drifting Lows, because at July end, the Vortex should not be strong at all.

EPSILON August September projection,   likewise with the warming from less pollution be,  the reverse happens fostering cooling with the lower in altitude sun.  A High at the Pole should be prominent by September,  typhoon remnants  with North Pacific Cyclones should start their South to North journeys which will last the fall to winter.    A great stall in weather should be in dominance much to the South.   Namely for a great chunk of the West Coast of the US.  To the East Hurricanes will appear rudderless, at the mercy of Atlantic anticyclones.  The jet stream will show some faint life signs at the Pole as well.

ZETA GRAPH.    The stratospheric ozone hole of 2020 reinforced  the said surface cooling over the Arctic Ocean of March 2020, or is it vice versa?  Nevertheless,  the tropopause was hard to distinguish during much of March above Cornwallis Island Nunavut Canada,  Upper air profiles in the troposphere had often much stronger than usual adiabatic profiles,  while the average said profiles between 2008 and 19 were much more stable and warmer.  In here lies the contradiction,  what fueled the more unstable adiabats in 2020?  I suggest it was largely thinner  sea ice,  prevalent everywhere throughout the Arctic,  as presented on my previous article,  925 mb level Arctic temperatures were warmest ever.....  Temperatures of the 1 to 3 kilometer greater in height tropopause of  2020 was often -80 C, an ideal temperature for atmospheric ozone depletions.  This greater height of tropopause is reminiscent of 2011, which had many destructive tornadoes.  The dissipation of the stratospheric polar vortex very strong center  will not relinquish its winds overnight.  Therefore the strong possibility of 2011'sh tornadoes,  but likely further Northwards than usual.  WD April 21, 24 2020

Friday, March 13, 2020

2020 Lower Polar Vortex shrank by 8.5 million square kilometers compared to 2012 , 2020 has smallest area every year since

~The lower in altitude Polar Vortex area right above surface of Earth is warming fast
~ Even compared to 2016,  El-Nino driven warmest year in history
~It is unquestionably clear,  warming at the core of the vortex is from over all thinner sea ice

From Jim Hunt's website :

There is not much doubt about how thinner Arctic Sea ice has become.  It may be even less than estimated:

NOAA daily composites January 1 to March 19 2020,  925 mb temperature average.  2020 is clearly  the smallest vortex area by millions of square kilometers.    From this overview, there is not much guessing as to why this current winter is amongst the warmest in history.    Again note,  the smaller the vortex the colder its Cold Temperature North Poles can be. This is a distinct feature of our current climate.  What is particularly interesting is the 2012  Canadian Arctic Archipelago  crescent CTNP  zone being nearly identical to 2020,  a precursor to 2012  atmospheric pattern leading to all time lowest sea ice extent at end of summer. WD March 13, 2020

Friday, February 21, 2020

Winter 2020 breaks 8 Omicron circulation cycle

~Major circulation pattern forces in a distinct climate result for spring summer 2020
~Similar in nature to spring summer 2019 weather
~Implying lots of rain,  as if it will be a surprise for Midwest North America and NW Europe
~8 Omicron pattern was noticed especially after 2012
~2020 breaks the cycle namely for Alaska-CCA-Midwest N.A. and NW Europe 2019 weather

 Introducing the 8 Omicron Arctic Polar Vortex pattern,  pay attention to 2012-13,  2014-15, 2016-17, 2018-19 morphology or the shape of the Vortex perimeter:

   8 Omicron mid-winter circulation pattern, 8 in shape for 2012, 14, 16 and 18, Omicron pattern 2013, 15,17, 19 and 20. From NOAA daily composites 600 mb temperatures (600 mb is the pressure level representing the average temperature of the entire atmosphere, 248 Kelvin, -25 C,  is where the Northernmost  jet stream can most likely exist).   It is a Ying Yang cycle, largely caused by gradual warming Oceans and Arctic sea ice minima melts and maximum reformation (cousin of warming oceans), especially considering lost sea ice volumes as the years went by.   Big news:  2019 2020 Vortex periphery  looks similar to each other,  despite 2019 being a significant melt summer.  I suggest the latest 2020 pattern is due to CTNP consolidating Northwards,  because the Vortex is getting smaller year by year.  This latest Omicron Omicron 2019-2020 vortex pattern,  infers 2020 being much like 2019,  except for Alaska being colder and being largely within the Vortex (colder) , not as it was largely out (warmer) every winter since 2012.  Refraction optical method monitoring the Western Canadian Arctic Archipelago should indicate how unique or split in two the Cold Temperature North Pole (s) will be.

     Meantime,  your wet soggy weather can be largely attributed to Omicron pattern whipping ocean air  straight onto the Western continental coasts,  as opposed to 8 shapes seasons diverting the Eastern oceans moistures and warmth Northwards.   Early prognosis for 2020:  hope you the enjoy more rain if you are East and West coasters,  the Ying and Yang of moisture,  mainly a consistent Pacific flow  joining the Atlantic Gulf stream making dry spots only within central continents  ....  WD February 21, 2020

Tuesday, February 11, 2020

Now that is strange, really different Arctic circulation patterns countinue

~Winter 2019-20 High Arctic circulation sharply deviates from preceding 8 years
~It means the sea icescape,  despite extent gains,  is really different

  February 11, 2020 NOAA animation loop courtesy CMC.    Yes a Cyclone from the Atlantic is heading to the Pacific straight from East to West.  Because the CTNP,  the North American Cold Temperature North Pole vortice is well South of the Canadian Arctic Archipelago.   Is quite warm over Ellesmere Island at present compared to further South.  Even though Ellesmere is still plunged in 24 hour darkness.   All in all, 19-20 winter is no recent year pattern repeat.  This feature announces more strangeness to come.  WD Feb 11,2020 

Saturday, February 1, 2020

Spectacular Surface Cyclone with no clouds was really a CTNP vortice

~ Arctic Winter 2019-2020 has a smaller Polar Vortex with many Polar vortices, with centers West of CAA, NE Siberia and even Alaska
~The Western Canadian Arctic Archipelago Cold Temperature North Pole vortice was quite spectacular:

  At times defined as a Low or High surface pressure, the extreme white Zone at the Western shores of Arctic Archipelago was the long lasting CTNP vortice of this region.  Where surface temperatures have easily attained near -45 C.  This is a continuance of smaller Polar Vortex geophysics.  CMC January 29-30  2020 IR loop portray the simultaneous encroachment of much warmer clouds moving quite fast while appearing being pulled around extreme cold air.   The combination of many vortices within the smaller in extent Polar Vortex created mainly above normal temperatures in populated areas of the Northern Hemisphere with the occasional spike of cold freakish weather as a result from rogue vortices,  which have been triggered by strong moving Northwards cyclones elongating the P.V. Southwards .  WD February 1, 2020

Friday, January 3, 2020

Coldest New Years Eve Cold Temperature North Pole in Meteorological history, since 1948

~Resulting from stable weather exacerbated and surrounded by a much warmer atmosphere
~First observed in spring 2017 by refraction sun disk method
~A surrounded shrunken by greater heat Polar Vortex gives deeply cold vortices.

     December 31 2019,  with Polar Vortex off center weighted temperature measuring -48 C CTNP over Ellesmere Island, the coldest such air ever measured for this date,  surpassing all others by 4 degrees C (1948-2018).
In Purple, deeply frozen weighted atmosphere using 600 mb, the rough altitude giving the average temperature of the entire troposphere.  Note the near proximity to much warmer air,  by +23 C, within a mere few hundred kilometers,   a feature of this phenomena.  In the past,  same date CTNP's were more Polar Vortex centric.  This amazing phenomena coexists with a much warmer Northern Hemisphere atmosphere.  With Jet Stream in some sectors way Northwards, at some locations brought Southwards by lower pressure found in huge cyclones.   Without Low pressure systems,  the outline of 600 mb at -25 C would be roughly the Northern end of the Jet Stream.  This small but impressive -48 C CTNP vortice is about 20 C colder than normal for this time of the year, compared to all other years since NOAA daily composite allows,  1948,  this region is the coldest New Years Eve in recorded history.  

The best way to explain this is to balance the presence of much warmer air, being onto itself more stable, especially during anthropogenic enhanced global warming days,  with a significantly smaller region of much colder air.  A weather stable region in darkness or with very low sun, is bound to get very cold,  because it is isolated, does not have a lot of heat input. This Ellesmere Island CTNP  is a continuance of the same one which was further to the West 3 or 4 days ago,  a cold vortice tends to place itself wherever ideal radiative cooling exists with very little heat advection or convection (from snow laced lands rather than thinner sea ice).   WD January 3, 2020

Monday, December 30, 2019

Christmas 2019 Polar Vortex shrinkage North American side; RECORD WARMING follows, how did this happen?

~From Chicago USA:

~To even Moscow:

~The root cause,  of course, was a warmer Arctic,  with likewise much smaller size Polar Vortex

     We go strait to the root cause:

  The size of the Polar Vortex on December 25-26  may be defined at 248 K isotherm threshold at level 600 mb.   As you can see the vortex is spectacularly small and covers even less ground over North America.    It has 3 vortices,  all quite cold, as per latest observations, the warmer the Arctic gets the more prone for small but very cold PV vortices.  Obviously there is no or very little circulation originating from the entire sub Arctic towards North America and western Eurasia.  How did it get this way?

      This was from a build up of unusual Arctic circulation pattern  covered here at EH2r since late November.     Namely by cyclones heading North from the West side of Greenland. 
Here was one of the last significant warm air blitz:

The recent Polar Vortex was not always shrunken,  December 19 to 25 action demonstrates one of the latest warm cyclones bringing up air from the West coast of Greenland,  all the way to Northern Siberia by way of the North Pole.  The culprit here is the Western Canadian Arctic CTNP (Cold Temperature North Pole),  a vortice of the vortices within the Polar Vortex.  Like a hurricane eye,  this vortice has been reorganizing according to the massive warm advection,  it could only reposition itself westwards,  within a much warmed,  hence shrunken PV as seen on my first NOAA daily composite animation presented above.    This shape of the Polar Vortex took place after several Baffin Bay cyclones headed Northwards likewise.  The sum total is a shrunken PV,  reorganized in similar way as before,  with a CTNP always prone in injecting more warm air in addition to the usual North Pole warming route,  from the North Atlantic.   Of particular interest is the weather of Japan, which will likely vary greatly from rainy warm days to Siberian cold in the matter of a few hours,   I have yet seen something which will break the current circulation pattern,  it seems quite stable,  but thinner sea ice may eventually reshape PV dynamics within 2 weeks. WD December 29,  2019

Sunday, December 22, 2019

Pacific air meets Atlantic clouds over the Pole

~North American  Polar Vortex Cold Temperature North Pole (its coldest vortice) did indeed move West
~Making for unusual weather, where cold mixed with Pacific moisture created Havoc regularly

We can see the brief outline of the North American CTNP over the Western Canadian Arctic Archipelago, NOAA CMC IR captures,   December 20 and 22.  Everything turns counter clockwise around it,  storms,  clouds and cyclones.  Which brings Northwards Pacific moisture to meet with North of Greenland Atlantic clouds very near the North Pole.  This CTNP has been severely weakened in a day,  the subject of coming next article.  WD December 22 , 2019

Tuesday, December 17, 2019

WARMING the Polar Vortex makes its internal vortices COLDER

~Dawn of winter 2019 looks as extreme as ever
~The coldest zone at start of winter since 2012 was 2016
~Yes,  the warmest year in history twinned with greatest El-Nino

     A continuance of warmer global temperatures creates smaller but much colder Polar Vortex internal vortices.

   The way to show this is by taking the ENSO cloud seeding theory,  which means there are more clouds during El-Ninos worldwide, either in summer or winter.   More clouds in Arctic winter definitely turns it warmer,  so was the great El-Nino of 1998 the turning point for Arctic sea ice extent , the beginning of its significant declining trend.    The  feedback of yearly ever increasing lesser sea ice areas should not be underestimated,  must remind: long in duration La-Nina's are destructive for sea ice, especially since 1999,  sea ice also plays a major role in world wide climate at either Poles.

     NOAA ENSO sst graph directly suggests the world is warming markedly because La-Nina's rebound from 2016 warmest El-Nino did not happen!  Hence cloudier Arctic summers since 2012.  But looking at peak warm/cold years reveals not only sea ice trends, but Global Circulation (GC) trends.  Obviously there wasn't the same mass of sea ice to counter 2016's warming.  2007 and 2012 summer sea ice historical all time melts were La-Nina driven,   not really counter intuitive because less clouds in summer Arctic spelt doom for robust very thick sea ice.  At any rate we look at warm years El-Nino 1998, 2003, 2010 and 2016, and cold La-Nina years 1999, 2007, 2011 and 2017.

Note, declining sea ice mangles ENSO's global circulation role year by year as sea ice volume and extent vanishes, it gives quite the interesting start of winter GC look,  note a couple of days at the dawn of winter are very significant if looked holistically,  a wide expanse of planet Earth is in effect an average compared with identical same day periods, long term averaging dilutes the GC outlines :

                             WARMER                                                              COLDER

      Consider the extent of Polar Vortex within the orange zone (the jet stream line), astounding as you may notice,  600 mb temperatures are very close to the weighted temperatures of the entire troposphere, but the coldest temperatures measured at beginning of winter were mostly during the warmest years, especially 2016, the warmest year.  Warmest years December 13-14's had much smaller jet stream outline (-25 C,  248 Kelvin border), colder years had naturally a vaster expanse of colder air but,  this is a big but,  mainly much warmer internal vortices.   Warmer years had mainly top of sea ice great warming incursions,   Cold Temperature North Poles (CTNP) were closer to the North Pole during colder years.

   The easy question is:  what causes this?  Refraction observations of vertical sun disk expansions or compressions have confirmed this phenomena.  During the last two springs, 2019 and 18,  the Canadian Arctic Archipelago Vortice (english language needs adjust to the times) was found radically colder but smaller.    Dark season long term observations rendered tentative conclusions,  the Cold Temperatures North Poles have largely migrated Southwards, away from lesser and thinner sea ice,  snow on ground species have tended to be more of the "wet" snow type,  more sublimation and mostly there seems to be a tendency for more stable but smaller cloud free zones,  which tend to be in a deep freeze feedback loop.

   What about 2019-20 winter:
   Same days dawn of winter look:  a vast tropospheric expanse over  the Arctic Ocean is warmer, the CTNP's are to the South,  meaning?  Rogue vortice formations much within populated areas, wild weather, warm to deep freeze merry go round all winter.  WD December 16, 2019