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Singularity

Arctic Sea Ice - The Melting Season 2019

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Extent is now 2nd lowest but the drops are still rather steady despite bit more in the way of favourable weather conditions. Either way the trends for the medium term are starting to look a bit more ominus with a ridge heading into the Beaufort which develops into yet another large high pressure cell. One to watch because it looks like the Greenland high is coming back with a vengeance so not promising signs for the crysoshere. 

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npsh500.144.png npsh500.240.png


I think ECM's actually got the right idea in keeping the blocking highs from making it back to Greenland; the strong westerly wind burst across the C. Pacific should kick the El Nino base state back into gear which promotes a mean trough position somewhere between W and NW of the UK, occasionally dipping further S (leading to thundery plume potential for the UK & W. Europe).

Hopefully I'm near the mark on this, as another round of Greenland blocking would be tragic for both the Arctic and the UK's weather prospects.


Even if we avoid that, though, the final warming has been so unusually strong that the blocking across the Arctic Ocean looks very slow to decline, and we're now reaching far enough into the year that the sun shining down through high pressure becomes capable of driving widespread top-down melting.

If a lot of melt ponds develop in the next fortnight, that'll be a big preconditioning factor for overall melt that's been mercifully absent for a number of years now.


Each time the Nino surges back, I find some cheer regardless, as coupled with a +QBO there is then a good basis for expecting a +AO pattern to become dominant within the next 6 weeks (and potentially by early June!). This should provide some welcome relief, unless the ice has experienced so much surface melt that, having already been so thin and fractured, it experiences mechanical destruction by even weak LP systems. There's a nightmare scenario that does not bear thinking about.

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Well the Beaufort high is now look like it will develop into quite a large one at 1040MB and the forecasts are looking more severe in respect of instead of the high migrating towards the pole which may allow troughing to develop, it now looks like it will stick around more or less the same area with southerlies as a result and the Beaufort Gyre in full force. All this likely to mean if it comes off is the Beaufort could have alot of open water in 7 days time, the wind flow looks perfect for this to happen. 

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I'm still not able to call time on the 'Perfect Melt Storm Synoptic ' yet this year? With forecasts looking to rob me of the opportunity again!

I have to wonder if the P.M.S.S is now altered to include large Arctic storms ( like the 'Great Arctic Cyclone' in 2012?) in August/Sept as a final 'coup de grace' for remaining ice?

Anyone care to chill me ( and the basin ) pease?

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Far from a done deal with the AO trend in June; there’s a risk that the downwelling proves too strong for more than just a bit of mitigation of the high heights, in which case I think something akin to a ‘perfect melt storm’ would unfold except that vigorous LPs could arrive in July to severely impact already Aug-like ice.

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Well I'm not holding my breath for a perfect melt storm for sure Singularity but I worry the damage do to the pack , and the ocean ,at high lats over this past 5 years or so?

I think some will have missed the denaturing of the ice there due to unrepresentative measuring of ice cover ( area/extent) with an algorithm invented to catch the ins and outs ( wiggly bits) of the ice edge.

If we had a measure of 80% cover = full cover of that grid I'm pretty convinced we would have seen year on year drops beyond 80N instead of this apparent 'stasis' there?

This has been occuring over 'average' melt/export summers so the first aggressive melt season we run into ( or is the basin so 'changed' they don't come around any more ?) will be carnage leaving the extent/area adherents wondering what the hell happened.

Again we see the Pacification of the Bering/Beaufort side of the basin messing with ice cover and our side has been empty all winter so Atlantic ingress has not stopped.

This early loss of ice leads to warming of the incoming waters to add to the salinity they already introduce ending up with hostile waters inside the basin heading ever poleward.

pinning down the first blue ocean event is pure guesswork esp. this end of melt season but we can be sure every year we see our plkanet warming means another year closer to that event.

With CO2 now over 415ppm Humans have never lived on the planet with so many GHG's in the mix but we all know what GHG's do to the atmosphere even if we have not been around before to see the impacts.

If we do not act I suggest folk sit on a chair, put their heads between their knees and kiss their ass goodbye!!!

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23 hours ago, Gray-Wolf said:

I'm still not able to call time on the 'Perfect Melt Storm Synoptic ' yet this year? With forecasts looking to rob me of the opportunity again!

I have to wonder if the P.M.S.S is now altered to include large Arctic storms ( like the 'Great Arctic Cyclone' in 2012?) in August/Sept as a final 'coup de grace' for remaining ice?

Anyone care to chill me ( and the basin ) pease?

Really? I think your perfect melt storm is coming into fruition as increasingly warm air enters the basin via the Beaufort sea. The ice in the Beaufort is going to take a beating and will be a lot of movement also leaving a large area of open water in that area. This pattern looks very persistent and there is really no signs of this pattern breaking down.

Only consolation will be the Laptev bite should not develop too much at this moment in time.

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The similarity with the average of the three biggest extent loss years since 2007 is striking, and here I've elaborated on the likely consequences.

Of course I can only say 'likely' due to the usual caveat; patterns could flip in June for all anyone really knows, though the extreme stratospheric warmth suggests this has a much lower chance of happening than it usually would.

It's alarming how the model runs keep correcting upward the blocking strength and persistence as it moves into the mid-range.

On a side note, it's interesting that even as the blocking shifts back toward or across Greenland, it's not necessarily looking like we in the UK will have to contend with being sat under a stationary trough; the high pressure looks so expansive that the troughs could well be focused S or SE of us. That really hammers home the extremity of the blocking pattern.

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When we discovered the return period for 'The Perfect Melt Storm Synoptic' (ten to twenty years) I do not believe we looked into what 'mechanism' drove the set up just that it did appear 'periodic' with the two prior to 07' respecting a ten year period?

Since 07' I have warned about the 'return' of T.P.M.S.S. but also wondered out loud if such can still exist with the changes to the polar trop/strat over the intervening period.

Now it looks like we will have our answer?

With insolation now reaching its strongest it is not the time for blue skies and 24  hr sun!

Next will be 'melt ponding' and whether such a fragmented pack can hold onto melt or if their small size means runoff and not pooling?

 

On the up side a record melt/permafrost eruptions will help Greta and XR highlight our real and present peril from a destabilising climate.......

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20 hours ago, Singularity said:

The similarity with the average of the three biggest extent loss years since 2007 is striking, and here I've elaborated on the likely consequences.

Of course I can only say 'likely' due to the usual caveat; patterns could flip in June for all anyone really knows, though the extreme stratospheric warmth suggests this has a much lower chance of happening than it usually would.

It's alarming how the model runs keep correcting upward the blocking strength and persistence as it moves into the mid-range.

On a side note, it's interesting that even as the blocking shifts back toward or across Greenland, it's not necessarily looking like we in the UK will have to contend with being sat under a stationary trough; the high pressure looks so expansive that the troughs could well be focused S or SE of us. That really hammers home the extremity of the blocking pattern.

The weather patterns reminds me of May 2011 with an strong warm high pressure cell affecting the Beaufort which sent a lot of WAA into the basin and the pattern was very persistent. In 2011, the ice was probably more resilient and the weather turned significantly colder at the end of the month which helped matters, not sure that will be the case this year. Also 2011 saw plenty of high pressure during June and especially July, dread to think what a repeat would do to this year's ice given what has happened already this melt season. 

Just looking at worldview just shows already what affect this high is having with the ice movement and the open water being left behind as a result, very likely during next week, we will be adding some heat to the mix but could this create sea fog and cloud and perhaps help the ice? 

Of course with the Alaskan side of the Arctic being warm, the Siberian side is colder but for how long. The models seem to suggest the cold trough will leave this region and head towards the pole and out into the Atlantic, not really what we want too see either. 

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Good points @Geordiesnow regarding the 2011 similarities for weather patterns but not ice integrity.

2011 set the stage for 2012 via thinning of the ice. The huge meltwater output, freshening the near-surface Arctic Ocean, was probably a part of why the 2012 extent started so high Jan-Apr.

 

Since those two years the question has been what happens when the newly much weaker ice is subjected to a strong melt season weather-wise. Until this year all we’ve really seen at that level is Jul 2015 and May 2016. Both weren’t enough in isolation to being record lows in Sep, especially Jul 2015 as it followed a relatively ice-friendly spring, but they did damage to volume just as 2011 did.

On that basis, this year is likely to at the very least do great harm to the volume numbers, breaking a two year run of slight improvements (or one, depending on which data source you use; I recall seeing one example showing a drop for Mar 2019 compared to 2018).

 

Signs of LP moving from Siberia to the UK vicinity are indeed ominous on many levels. Hopefully the amount of movement is being overdone via modelling too few complications in the flow.

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