The 2018 melting season

[aperson]

First GAC of the season? The ATL front is about to get... quite a wallop. GFS upped ante and heat at 00z.

~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Edit: You may also want to download and reupload those analysis images since they will break once it cycles out of TropicalTidbits range (I think they store the last month's of runs).

[bbr2314]

Eh. We'll have the satellite data soon enough!

CMC agrees with GFS, which means we should be "game on" since it is way more reasonable re: heat. And even then, it is an absolute torch.

[bbr2314]

Continental heat pulses becoming increasingly extreme, people already dying en-masse in Pakistan and we haven't even hit the beginning of the 50C+ readings which will be widespread and worsening by D3-4. This is going to have some impact on the Arctic as the extant snowcover in northern Siberia and the Himalayas act as enormous cannons/anchors for negative 500MB anomalies & LP, firing heat surges north into the Siberian Seas and CAB (as we see in ^^^ output).



YIKES!

[jdallen]

Eh. We'll have the satellite data soon enough!

CMC agrees with GFS, which means we should be "game on" since it is way more reasonable re: heat. And even then, it is an absolute torch.

<SNIPPAGE>

Looking at Climate Reanalyzer checking snow cover and pressure, you can see the low forming up in the western Kara in about 36 hours.  Over the next 96 hours or so, it looks like the weather will absolutely crush any remaining Eurasian snow cover and seriously smash snow cover on the Arctic pack.

That's about as far as I'd trust the forecast trend, but at hour 96 it does like we have a pretty good dipole set up running from the Laptev/Eastern Kara towards the eastern CAA, with a pressure differential of about 48MB (1026 vs 978).

At 72 hours as shown we have 15-20C+ anomalies predicted for most of the Siberian coast all the way Scandinavia.  Also visible indirectly is the huge "wheel" of the air masses with warmer air rotating into the Arctic from central Siberia and the colder Arctic air being driven into eastern Europe.

If the models follow what actually happens, but the time we get 6 days out, Northern hemisphere snow cover will be reduced by over 70%, and snow cover on the pack by over half.

Look for extensive melt ponding everywhere outside of the area directly north of Greenland by June 10th if this plays out.

[jdallen]

I'll take the liberty here to add the current 12Z estimated snow cover/air pressure and what it's estimated to be in 72 hours.

[meddoc]

Continental heat pulses becoming increasingly extreme, people already dying en-masse in Pakistan and we haven't even hit the beginning of the 50C+ readings which will be widespread and worsening by D3-4. This is going to have some impact on the Arctic as the extant snowcover in northern Siberia and the Himalayas act as enormous cannons/anchors for negative 500MB anomalies & LP, firing heat surges north into the Siberian Seas and CAB (as we see in ^^^ output).

India & Pakistan both Nuclear Powers. Sharing the Himalayan Freshwater Reserves with- You guessed it- Nuclear Power China....

[Alexander555]

~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.

[bbr2314]

~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.

The impact of this would be sustained days of 100K+ losses (IMO). EURO follows GFS.

[bbr2314]

I'll take the liberty here to add the current 12Z estimated snow cover/air pressure and what it's estimated to be in 72 hours.

It looks like the GFS is initializing incorrectly because MODIS shows much more extensive snowpack over Quebec vs. the estimated cover. This is not surprising because the GFS is terrible at snowpack . Losses will be impressive over the next week but the GFS is probably overdone (and more importantly, it appears to start out UNDERdone).

[aperson]

~60mb pressure gradient and a closed circulation all the way up to the 200mb level. Yikes, I'm definitely staying up for the 00z ECMWF tonight to see its take.


Aperson or bbr2314, if you would have time. Is it possible to describe the things you are talking about in other words. And what the impact is.

In the Sea Level Pressure charts posted above, the pressure difference from high pressure (~1025) to low pressure (~965) is around 60 millibars.

In these graphs you will see isobars of equal pressure drawn around the high pressure and low pressure centers. The tighter these isobars are, the faster wind flows along them. In the northern hemisphere, low pressure rotates counter-clockwise, and high pressure rotates clockwise, so this should let you figure out the direction of the wind.

The wind that flows along the isobar contours of constant pressure is known as geostrophic wind. See this for reference: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/geos.rxml

From this exercise, you can work out how strong wind is blowing and where it is bringing air from just by looking at the Sea Level Pressure charts. This lets us figure out that lots of heat is being brought in from the midlatitudes with strong winds in the charts posted above.

[FredBear]

Re: Reply #954
The 2m 0°C isotherm (orange line) probably limits precipitation to snow (not rain) even where any warmth tries to go into the Arctic? New snow will protect any ice it falls on until it becomes "old snow" and loses it's albedo - which may not be long these days!

[uniquorn]

With Kara and Barents first in the firing line, here is amsr2 uni-hamburg concentration map for the melting season mar21-jun3.
Eastern Kara/Barents have been mobile all season with some refreeze between older floes. This younger ice will not last long in strong warm winds if the forecast plays out.

[F.Tnioli]

...
At 72 hours as shown we have 15-20C+ anomalies predicted for most of the Siberian coast all the way Scandinavia.  Also visible indirectly is the huge "wheel" of the air masses with warmer air rotating into the Arctic from central Siberia and the colder Arctic air being driven into eastern Europe.

If the models follow what actually happens, but the time we get 6 days out, Northern hemisphere snow cover will be reduced by over 70%, and snow cover on the pack by over half.
...

It's been my understanding that such a "wheel" is one of required circumstances for Blue Arctic event (among few others), having it happening exactly this time of the year (late May / early June) and persisting, with possible short slowdowns, for over a month. One can perhaps call it "GJB" - "Great Jetstream Breach", akin to how we routinely say "GAC" about big arctic cyclones now. AFAICT, GJBs will be inceasingly strong and frequent as seasons go by.

Not only it will quickly remove snow cover and melt/rain pond much of ice, but it also significantly increase current athmosperic energy content in NH, since all the cold air transferred to eastern Europe and such - will lose less energy nighttime than normal-temperature-there air, and similarly accumulate more energy during daytime (Stefan-Boltzman law), while 24/7 or nearly 24/7 sunlight in Arctic will make sure there is no "increasd" heat loss there during nighttime (since there is none, at the time).

So my question is: what you gentlemen think, by now - how long this "wheel", this cross-Jetstream air mass ~circular current of continental proportions, could persist if it will form exactly as forecasted?

[Pagophilus]

That storm looks like it will hit all that fragmented ice in the north Kara Sea between Fran Josef Land and the Russian coast, so the effect is likely to be considerable -- buffeting floes, smashing thinner refrozen ice, generating large waves etc (as opposed to those high winds sweeping over continuous ice cap without penetrating it and thereby not causing waves).

First GAC of the season? The ATL front is about to get... quite a wallop. GFS upped ante and heat at 00z.

[bbr2314]

Strongly agree. It also looks like it will eventually bring rain across the Siberian Seas through to the Chukchi. The combination is likely to deliver a critical blow at a time when melt ponding & retaining extant albedo is absolutely most critical (this event will come close to coinciding with solstice, which is extremely early / earliest ever in the season (?) I can recall a storm like this?

[jdallen]

Re: Reply #954
The 2m 0°C isotherm (orange line) probably limits precipitation to snow (not rain) even where any warmth tries to go into the Arctic? New snow will protect any ice it falls on until it becomes "old snow" and loses it's albedo - which may not be long these days!

Not sure that will be the case here Fred.  I expect there will be higher temperatures aloft, and the h2o will be carried as moisture or vapor, not ice crystals.

The net heat budget should be generally positive, which should prevent snow except at the highest latitudes.

[jdallen]

Strongly agree. It also looks like it will eventually bring rain across the Siberian Seas through to the Chukchi. The combinateion is likely to deliver a critical blow at a time when melt ponding & retaining extant albedo is absolutely most critical (this event will come close to coinciding with solstice, which is extremely early / earliest ever in the season (?) I can recall a storm like this?

What happens on the Pacific side is a concern as well, as all the models are in pretty close agreement out to 72 hours.  Besides the storm which will wreck the Kara and Barents to start, we have persistent hiigh pressure from the Laptev to the CAA.

Other things to note - the string of systems, high and low, along the eastern north American/Atlantic margin which will tend to continue shoving heat north, similar setup along the rockies, and the dipole set up to torch the eastern Kara/western Laptev.

Hard to find good news there, especially within the 72 hour envelope descibed.

[Greenbelt]

Worldview shows the developing cyclone

[A-Team]

What is left in the Chukchi and Wrangel is in worse shape in post-normalized visible than it appears in synoptic radars. The browning could be air pollution from Asia, smoke from wildfires, dust from the Taklamakan desert, algal surface growth, or embedded particulate deposits in snow being concentrated by melt and so on. It has been around for several days with today being the worst.

The area has been mostly cloud-free so the browning has been contributing to sunlight heat retention whether still airborne or on the surface of the ice. However it is only one of several forcings currently underway.

The image below displays at larger size with a click or view interactively at Nasa Worldview, save image and linearly adjust contrast.

 https://tinyurl.com/yctb26xn

[marcel_g]

...
YIKES!
...

Well, this is certainly one of those Holy Shit predictions that make this thread impossible to put down. For me anyway.


After this melt season has kind of muddled along, and I was thinking there might be a chance that it could get cloudy just in time for June and stave off the melt ponds and solar absorption.

But looking at those images, and climate reanalyzer and it seems that the only positive in the next few days is going to be that the arctic won't be completely sunny, but that is a lot of heat and moisture plowing all the way across the entire CAB.

If the sun comes out afterwards, then wow.

[Lord M Vader]

The latest operational EC 12z forecast is completely brutal for the sea ice! Expect an onslaught in Kara-Barents Sea followed by high pressure centered in the CAB and Beaufort! The only thing that would be worse is a dipole setting up over the Arctic. No such is in sight at this moment.

[uniquorn]

With the warm pulse continuing on the Pacific side, ECMWF WAM forecasts 2m waves in the Chukchi from Thurs to Sat. Clearer weather today and in 2017 gives an opportunity to compare the state of the ice over the 2 years.
Although melting at similar rates so far, with 2018 slightly ahead (2017 in orange on Wipneus chart), probably due to the early melt in the Bering Sea, there is a distinct lack of large floes this year, and the current weather suggests that melt will keep pace with 2017 over the next week or so.
The animation takes a broad view of the Chukchi, then zooms in on 3 areas, showing 2017 first in each case.
Looking at it again, 2018 ice does look browner than 2017.

tech note:
all worldview images filtered using imagej unsharp mask 1,0.5

[jdallen]

The latest operational EC 12z forecast is completely brutal for the sea ice! Expect an onslaught in Kara-Barents Sea followed by high pressure centered in the CAB and Beaufort! The only thing that would be worse is a dipole setting up over the Arctic. No such is in sight at this moment.

Take a look at the 12Z run at around or about +72 hours.  That looks awful dipole-ish.

[jdallen]

What is left in the Chukchi and Wrangel is in worse shape in post-normalized visible than it appears in synoptic radars.
<snippage>

With high pressure, sunlight and above freezing temperatures, like 4-6CM of top melt a day worse.

Most of that ice sans relict MYI was 1.75M or under, IIRC.

I'd say most of that ice will be gone by the end of the month.  The albedo is way to low.

[Hyperion]

Meanwhile on the oceanic heat front, Mr Atlantic seems to have hit the nitrous. We have a very coherent and rapid Gulfstream flow hitting speeds near five thousand km per month. I've not before seen its like. Could be the start of a much feared but rarely mentioned superfast Gulfstream pulse that some scientists claim to have identified in the paleo record associated with major melt pulses coming out of the ice ages. Maybe there will be no Arctic winter this year.

[numerobis]

http://nunatsiaq.com/stories/article/65674cold_spring_breaks_records_in_nunavik_nunavut/

As we saw it was a cold May in Nunavut, Nunavik, and Nunatsiavut (but not Inuvialiut). Kuujjuaq was almost 6C below normal; Iqaluit 3C; Rankin 3.6C below norm.

[jdallen]

Meanwhile on the oceanic heat front, Mr Atlantic seems to have hit the nitrous. We have a very coherent and rapid Gulfstream flow hitting speeds near five thousand km per month<snippage>. Maybe there will be no Arctic winter this year.

A bit soon for that speculation, but the idea of a big pulse of "hot" Atlantic water arriving at the doorstep of the CAB at the end of July is unsettling. 

By then, the Kara and Barents ice should be gone, so it's immediate effect will depend on what ice gets swept over it by circulation, or how much heat gets into the basin proper and applied to the ice.

The bigger question will be what it does to the end of the melt season, if it extends it, and how much the weather is affected.

[Aluminium]

Forecast from earth.nullschool.net for 07.06.2018 09:00 UTC. There are winds up to 72 km/h, total precipitable water over 25 kg/m², T850 about 10°C.

[FishOutofWater]

The Florida current cable shows the Gulf Stream moving right along for the past 6 weeks, but it's moving on the high side of the normal range. There's definitely a strong sea surface height gradient across the subpolar gyre so that part of the Gulf Stream system will be kicking into overdrive. There has been a stunning amount of poleward heat transfer by the atmosphere over the north Atlantic for the past 6 weeks.

[bbr2314]

The Florida current cable shows the Gulf Stream moving right along for the past 6 weeks, but it's moving on the high side of the normal range. There's definitely a strong sea surface height gradient across the subpolar gyre so that part of the Gulf Stream system will be kicking into overdrive. There has been a stunning amount of poleward heat transfer by the atmosphere over the north Atlantic for the past 6 weeks.

And it is only going to continue. SSTs should be warming dramatically over the far NATL for the foreseeable future. This year is truly going to torch.

More immediately, the 00z GFS ups the ante on the first GAC.

[bbr2314]

Consensus continues to deepen, Canucks join GFS.



CAB rainy heatwave extending across all Siberian Seas





There looks to be a lot of very fragile ice in the path of the upcoming event. The melt ponding on the areas that aren't will be severe. Will we see a cliff of several 100-200K daily losses?

[aperson]

00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC:

[jdallen]

00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC: ...

If it happens it will be like pulling a zipper across the central basin.

[meddoc]

00z GFS Animation 0h - 168h of the possible trajectory of the possible GAC: ...

If it happens it will be like pulling a zipper across the central basin.

Hycom shows a huge crack starting from the Atlantic Front into the Direction of NP

[aperson]

I've been looking for a quick way to validate temperatures from models across the Arctic. VIIRS Brightness Temperature (Band I5, Day) and Night overlays seem to work pretty well. In tandem with using Terra / MODIS Bands 7-2-1 to locate clouds, one can look at the surface temperatures where there are no clouds.

Here is June 4th with the day band overlayed. The lowest shaded bucket is 270.9-271.6K (-2.25C - -1.55C). Above freezing temps occur at the transition to purple and max out at 4.05C.


(https://i.imgur.com/Ai5kMi8.jpg)

Here is a link to Worldview which has this overlay specified for VIIRS day and night bands: https://worldview.earthdata.nasa.gov/?p=arctic&l=MODIS_Terra_CorrectedReflectance_Bands721,VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Coastlines,VIIRS_SNPP_Brightness_Temp_BandI5_Day(opacity=0.67,palette=rainbow_1,min=270.9,271.6,max=276.6,277.2,squash),VIIRS_SNPP_Brightness_Temp_BandI5_Night(hidden,opacity=0.67,palette=rainbow_1,min=270.9,271.6,max=276.6,277.2,squash)&t=2018-06-04-T00%3A00%3A00Z&z=3&v=-2860023.1037379596,-1120673.8055663547,3038216.8962620404,2700894.1944336453

My biggest takeaway is that the open water on the Pacific side is a kill zone for ice that gets transported into it.

[aperson]

Euro bottoms out at 972mb. Winds from peak intensity provided below.

[uniquorn]

Continuing the thawing river series, here are the Shelonsky Islands at the mouth of the River Chondon, east of the Lena delta. Jun2-5

Worldview terra/modis corrected reflectance true color and band 7,2,1

[Pagophilus]

Nullschool shows possible unfolding of events in terms of all that fragmented ice in the northern/eastern Kara Sea.   It shows two days (including today) of strong, warm winds blowing ice floes in northern/eastern Kara Sea towards and perhaps into the ice-free Barents.  Followed by two days or more of powerful winds swirling those floes vigorously around.  Waves will get a head start since there is quite a lot of open water in the ice openings parallel to the Russian coast in the extreme eastern portions of the Kara. 

Wind speed readings are for the area just to the right (or south) of Franz Josef Land (green circle dot just visible).  I chose this because it is near the current ice 'edge'.

[A-Team]

The MacKenzie started flowing into the Arctic Ocean on about May 30th; the weather at the delta has been cloudy. The 4th of June was clear however. The swath for June 5th is not yet available from WorldView.

Landfast ice is breaking up somewhat and on the move. This date is not unusual for inflow of fresh water here. While it affects salinity and heat of this corner of the Beaufort, it is not currently affecting any area not already melted. While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.

[bbr2314]

12z GFS down to 959

[aperson]

While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.

The silt is also accumulating heat rapidly. Above freezing values are shaded in 0.6C increments starting at -0.3C - 0.3C bucket. The hottest regions are currently around 4C. Models are showing ice getting transported into this region in the D4-D8 range due to actions of the upcoming Arctic cyclone.


(June 4th worldview).

[Hyperion]

 
And this little children is how we first experienced the awakening of the Atlantic Kraken way back in 2018. Plunging Europe into the tropical monsoon climate we know so well today and rapidly ridding the arctic of this thing we used to call ice. The Kraken began hurling one dripping fisted tentacle a day at the Atlantic north, Europe, and the Arctic ocean back then and almost never paused since in his fury.
One for the ESAS,
Two for the floes,
Three for the Green islands,
Four for Newfoundshoal,
Five from New Fork archipelago,
And so on shall it go?

[Grubbegrabben]

12z GFS down to 959

Reposting what bbr2314 said but with this additional quote from the Wikipedia topic "Great Arctic Cyclone of 2012" https://en.wikipedia.org/wiki/Great_Arctic_Cyclone_of_2012.

On August 6, the extratropical cyclone reached a peak intensity of 962 mbar (28.4 inHg), while centered about halfway between Alaska and the North Pole.[1] At this point, the Great Arctic Cyclone of 2012 was the strongest summer Arctic storm on record, since the beginning of records in 1979.

Also screenshot from Nullschool below. This happening in early June as compared to August 6 should have some implications...?

Edit: The location/path of the cyclone does not seem as detrimental as 2012, but I know way to little about this to develop the reasoning further.

[aperson]

12Z ECMWF bottoms out fairly early as well with a minimum SLP of around 970hPa. Given the different location and timing of this cyclone compared to the GAC, I think the effects will be qualitatively different and we will need to hold on any comparisons until reanalysis. However, this setup appears to be catastrophic.

[A-Team]

Scientific animator extraordinaire, Kevin Pluck, has some outstanding Arctic and Antarctic graphics on his twitter site ... the one below shows how the weekly ratio of extent to volume has drifted over the years. The loop pinches from 2009 on, explained as a skewed sine curves for the volume and something that produces a sharpish valley for the extent curve'.

The second link below can be used to capture twitter mp4s though that mp4 still has to be converted to forum mp4 using the third link.

https://twitter.com/kevpluck
http://twittervideodownloader.com/
https://www.online-convert.com/

[oren]

Great animation.

[A-Team]

While not the main weather event at the moment, the weather that swept in from far eastern Siberia over the Chukchi and Beaufort had the effect of disrupting our four favorite radar wavelengths for a couple of days.

There are two Ascat satellites A and B imaging 12 hours apart, making it possible to intercalate them to get slightly smoother image motion. Below, the upper part and elbow of the CAA stringer in the Beaufort-Chukchi are disappearing from view from June 3rd on. The shorter wavelength imagery often has an unwanted weather overlay but Ascat has been largely immune to artifacts for the last ten months.

That's unfortunate since the constituent floes have been trackable since late September. Ascat looks at roughness, more pronounced in MYI; the storm may have had the effect of melting off the rough edges  which makes them less reflective and so darker and not in good contrast with surrounding FYI. Alternatively, the old floes may come back into view as the weather system passes through.

[Ktb]

Slater projection shows ice beginning to open in the CAB for July 25th, extremely close to the pole. Extent of 7.42 mil km^2 at that time.

Edit: foolish me, the CAB is already opening thanks to significant torching. I believe the extent graph to be correct but the actual map to be today's date rather than a forecast 40 days out. I will contact UofC once again.

[oren]

Thank you A-Team for these numerous Ascat and other animations.

[Pagophilus]

Maybe I am missing something, but that Slater projection for July 25 looks a lot more like the current ice extent from AMSR2 for June 5 (today) than it looks like, for example, the actual ice extent for July 25 last year (see below -- I've put all three maps together).  In addition to that, we are at the second lowest measured extent since 1979 for any June 5 right now, implying, at least, that ice extent should look something like last year's extent on July 25.  To me, the Slater forecast looks strange, and I would be glad to be enlightened.

AMSR2 image for July 25 2017 is a little smaller scale than the other maps... apologies.  Pattern of lower extent is still obvious, though.  No ice in Baffin Bay, Hudson Bay, Kara Sea, most of ESS free of ice etc.

Slater projection shows ice beginning to open in the CAB for July 25th, extremely close to the pole. Extent of 7.42 mil km^2 at that time.