Cryosphere > Permafrost

Northern Hemisphere Winter 2018-2019 Snowcover / Misc Obs

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bbr2314:
I am starting a new thread for this since we are at the dawn of a new freezing season, and snows are now falling once more over the highest latitudes.

I think the main question to ask this winter is, will we see a repeat (or worse) of 2017-2018's anomalies? Besides that, if we see anomalies skyrocket as we did in early 2018, will we see a similar result in the spring of 2019 re: all-time historical record cold across many portions of North America (or elsewhere)?

I would like to begin the discussion with a few key observations.

1) The Bering Sea has been ice-free for more than 365 days across most locations. It has been accumulating heat like never before. In fact, much of it may have become entirely ice-free due to the ongoing situation since 2007-2012 and residual accumulations of oceanic heat.

2) The situation in the High Atlantic is similarly perilous. The ATL front has been at its most-withdrawn ever position this year, and we still have a month of melt season to go. How much additional retreat do we see north of Svalbard, and how anemic of a refreeze will we see this year?

3) The situation in the ATL has been, IMO, partially caused and exacerbated by the extremely early melt-out of Scandinavia (which, combined with the late melt out of Quebec, resulted in forcing of +++anomalies over much of Europe this summer). Will this extra heat mean that refreeze in 2018-19 is even more anemic than what we saw in 2017-18? There is also the heat content in the NW NATL S of the cool pool which has been making its way to the NE NATL in spurts. This will continue arriving through winter.

4) The situation this spring and summer have severely worsened the ATL cool pool E of Quebec and S of Greenland.

And now, for questions.

1) Snows are already falling, or will be imminently, over much of the Canadian shield. Will early snowfalls (assuming they are sustained, and I see no reason they wouldn't be given the "stuck" pattern we are in) allow colder airmasses over Quebec/etc earlier in the season than normal? Will this worsen the cool pool as a result?

2) What happens in the High Arctic if we see early continental albedo anomalies this year, combined with residual oceanic +++anomalies in the Bering, Laptev, and Barentz? Will the dislocation of the cryosphere to more northerly mid-latitudes so early on cause even MORE oceanic heat to be advected north, prolonging the melt season for the High Arctic (or at least delaying refreeze)?

3) What years are the best analogy to our current situation, and based on those, what can we expect moving forward?

Interestingly enough, the closest recent match appears to be 2014. It features a nearly identical pattern of anomalies across the NHEM for the first two weeks of August. In fact, the only difference this year is MORE heat over the High Arctic (it has actually been warmer than 2012 as well, though the overall pattern has been WAY different).

I would argue that the similarity may be due to the Laptev opening so early in both summers. This "highest of latitudes" oceanic ++++anomaly may be the driving factor that forces cold to "stay" in North America vs. giving it more leeway (i.e. the traditional jet), and distributing it across the entire NHEM.



If the summer of 2018 is any indicator, we will see even more blocking than we did in 2014-15. ENSO conditions are somewhat similar but the Arctic is even warmer than that year.  But, the patterns are still fairly similar.

If a similar winter to 14-15 is realized, but with more high latitude blocking in the same regions seen that year, we are likely to realize severe negative temperature departures for DJF across most of North America east of the Rockies. Additionally, Western Europe could also be prone to colder weather than 2014-15, as the residual effects of a colder Quebec / etc = cooler cold pool, cooler cold fronts into W Europe from the NATL. It should be noted that the spring of 2015 saw the development of a major El Nino event simultaneous to severe and enduring -springtime anomalies over my favorite Canadian province. Perhaps this portends another strong ENSO event in 2019, and a similar situation to the spring of 2018 over the same regions previously impacted?

This, funny enough, would also follow the pattern set in 2012 (severe melt year), 2013 and 2014 (relative recoveries but cold winters, and 2015 (severe melt year). 2016 was a severe melt year without major ENSO, 2017 and 2018 are both looking like "relative" recoveries in dubious ENSO waters, while 2019 could be our next equivalent to 2015, meaning both 2019 and 2020 could have bad conditions for preserving sea ice.

Thoughts welcome / criticism & contribution of ideas also welcome, please no personal attacks :)

Alexander555:
There are vast area's in the pasific ocean where the temperature of the water is like 1 to 2 degree C warmer than normal. That should create the conditions for the moisture you need for your snow. Can you tell something about the wind paterns that bring most of the snow to Canada ? Are they the same for the West and the East ?

Alexander555:
When i watch Ventusky, i see that the rain in the US always travels from the west to the east. It enters the US north of California. And than it crosses the entire continent. In the east you have the winds coming from the Gulf of Mexico and than moving North, North-East. And you have the trail the hurricanes (and nor'easters) in general take. So where does the snow in Quebec in general comes from ? The Pacific seems to be warm, the gulf seems to be warm. And the trail of the hurricans over the east coast looks colder than normal. But i think they are going to get a healty dose of snow. And that could slow down the effects of global warming in some locations. Like you say, a higher albedo. And colder winds, more meltwater....... So where does the snow comes from, or is it a mix ? This could be something nice to follow up in the next year.

bbr2314:

--- Quote from: Alexander555 on August 19, 2018, 02:59:50 PM ---When i watch Ventusky, i see that the rain in the US always travels from the west to the east. It enters the US north of California. And than it crosses the entire continent. In the east you have the winds coming from the Gulf of Mexico and than moving North, North-East. And you have the trail the hurricanes (and nor'easters) in general take. So where does the snow in Quebec in general comes from ? The Pacific seems to be warm, the gulf seems to be warm. And the trail of the hurricans over the east coast looks colder than normal. But i think they are going to get a healty dose of snow. And that could slow down the effects of global warming in some locations. Like you say, a higher albedo. And colder winds, more meltwater....... So where does the snow comes from, or is it a mix ? This could be something nice to follow up in the next year.

--- End quote ---
The air currents to Quebec have increasingly originated in the CAA / Greenland instead of the Pacific. It seems the further N &E you go in North America, the bigger the shift has been (due to +500MB ridging dominating the W). This allows the Polar Jet (or whatever remains of it) to have a far smaller but much more potent circulation (i.e. this summer's 500MB maps), where its reduced size is not accompanied by fewer storms, rather, they just hit much more frequently. You can roll the EURO forward on tropical tidbits and see how the pattern is circulating the same airmasses from Greenland into the srn CAB / CAA, into NWT / Quebec / The Shield, and then off into the ATL where they pick up the +oceanic heat, deposit it into Greenland, and cycle back for the return trip.

Niall Dollard:
Alert, Nunavut, is off the mark today. Last week it was only reporting trace amounts of snow, but at 12Z it has 4cm lying.

With temps near or a little below zero, the snow is more of the wet variety. The 4cm coming from a 24hr precip total of 5.7mm.

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