csnavywx

The EC op and EPS paint an interesting picture. After the current TPV starts migrating away at t+72, a big subtropical intrusion starts from the Russian side over the ESS. Temps at 700mb rise to 5+C and 500mb temps get above -10C, denoting the deep subtropical characteristics of the airmass, along with high TPW/theta-e. Most importantly with the strong WAA is the forecast wind strength and fetch, which would enable these temps to mix down effectively. The EC OP is a knockout blow from D5, but I won't speculate much past that due to the limited recent model skill. Definitely a potential watcher for the Pacific half of the basin.

It's a good question. Looking at EOSDIS shows much of 2013's ponding on this date was confined to the periphery while much of the CAB snowpack survived until late July. This year shows ponding deep into the CAB -- not as extensive as 2012, but not far terribly far off either. This year is lagging behind 2012 in the Kara/Barents and Beaufort in open water coverage but ahead in the Chukchi and ESS. The EC/EPS is backing away from a strong PV in the D5+ time period. Looks like the seasonal pattern of rapid switching will continue. I'm really torn on how to go for minimum. Maybe a blend right down the middle with a large area of broken/partial coverage (not too dissimilar from last year). Volume not too dissimilar from 2012 (maybe slightly above) with extent well above.

After a slowdown with the PV pattern last week, the basin has lost-724k in area from the 30th-4th (on NSIDC).

PIOMAS actually stayed slightly below 2012 -- or a statistical tie, so it definitely hasn't lost much ground over the past 2 weeks. Most of the gap closing occurred early in the month. Current anomaly is the lowest on record. As far as the state of the pack is concerned -- it's definitely weaker on the Pacific and ESS-Laptev front and definitely stronger on the Atlantic/Kara side. The dipole shuts down after D5 (as far as the OP runs are concerned) and a cool PV pattern is dominant on the ensembles. This year has waffled rapidly back and forth, so we'll see if that continues.

Ironically, a great deal of ponding has shown up over the past 5 days on EOSDIS. The strong winds, WAA and chinook-type event off the Kolyma range on the forward flank of the storm did a great job of breaking the inversion and eradicating snow cover, jumpstarting melt-ponds. The O-buoy 14 pictures show that as well, going from solid snow cover to solid melt ponding in less than 2 days. Melt should slow considerably for the next 3-4 days. However, the upcoming pattern has downsloping flow off the Brooks range for an extended period, which will serve to push the Chukchi/Beaufort front back pretty quickly.

There's evidence of significant Atlantic water shoaling over the past 5-10 years. Neven's site had some stuff posted from this paper: https://www.ncbi.nlm.nih.gov/pubmed/28386025 I believe the AW layer was found to have shoaled about 50% of the way to the surface in the last decade on the Eurasian side -- hence the paper's statement of a significant fraction of forcing coming from the ocean now. The issue there is that with additional shoaling, even weaker summer storms will be able to tap that water layer and cause it to interact with the near-surface layer. That may have been part of the issue last summer. I'm pretty sure the Pacific current played a role there too -- but as you say, it'd be nice to confirm that. Your comment on winter warmth is about right. This winter's FDD anomaly total was around -1750. At around 2000, it begins to seriously undercut spring thickness and at 2500+ maintaining FYI gets pretty untenable even through a cool summer. There isn't much buffer room left there. The good news is that last winter was pretty extreme compared to any other winter, so there's a good chance we'll get a mean-revert this year.

Gotta go back to Aug. 2012 to find a cyclone as powerful as is being progged next week at this point.

Yeah, the EPS is now pretty adamant that just about the entire basin goes cold. I'm beginning to think the current +PDO/warm ENSO stretch is inhibiting any lengthy dipole development. There have been a couple of papers hinting at this outcome recently. You had one a couple years back relating to this issue as well, I believe?

Good point about the Hudson. It's been wrecked pretty hard this season and probably can only contribute for another 10 days before there isn't much left (it's almost all grey ice at this point). EOSDIS does suggest some ponding has developed in the ESS, Laptev and perhaps the Barents, but given the colder weather on the way, I doubt they'll contribute much over the next 10 days.

Very solid area drops the past couple of days (per Wipneus's homebrew calcs). -192k for the 14th and -128k for the 15th. Couple more days of decent drops are probably coming before cooler weather sets in. It will then depend on exactly where that advertised TPV sets up and how strong it is. A TPV positioned near the pole will of course result in much slower losses -- whereas a position over the Laptev or coast there will hasten Fram export and cause the Chukchi/ESS open water front to rapidly advance. Either way, it's probably still better than the dual ridge we had over the past week given the temperature drop.

Looking at individual years, it doesn't show up every year, but it shows up quite a bit from here on out. Some years are just as cold, if not colder this year.

Just out of curiosity, I went through the CCSM4 output on Climate Reanalyzer and looked at that region out through time. Something interesting popped up: If I expand the timeframe to 2021-2040 vs 2001-2016, it's still there:

Wow, that's a big drop. Pretty surprising, even with the high variance.

Yep, this exactly. It's not a quantitative thing by any means, but still useful, imo. It only goes back through 2012 unfortunately, but it's got enough to start making comparisons. *Edit for typo.

Agree here. There's a big visual difference in ponding between years in which that snowcover disappears early and years like this one and 2013 where it takes a while longer. We haven't seen that much snow cover along the Siberian coast this late in over 10 years, maybe since the 90s.

Sorry, should've been more clear, I'm referring to EOSDIS Worldview and scrolling between years on this date: https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-06-12&z=3&v=-3714337.5732286554,-1744121.4245445705,4149982.4267713446,2552582.5754554295

Posted on Neven's forum. Definitely fits the bill of high snowfall retarding melt. Going to take a good dipole pattern to reverse that.

I don't really think that's going to happen for a couple of weeks at least. Maybe if the dipole showing up at D5+D6 comes to fruition. One would have figured the "bridge ridge" of the past few days would have done more damage, but that just shows how much snow is still there. Even 2013 had more melt ponds at this point looking at the daily worldview plots, even if it did have a lot less open water.

A 2007 pattern starting in late May would have done it this year I think. But that's an exceptionally bad pattern -- ergo pretty rare. This year is a bit wierd. We've got record low starting volume, but high adjacent land snowcover and a decent snowpack left on the ice in most areas. There isn't as much blue ponding on Worldview this year as last year or 2012, for instance, but there's a lot more open water in the ESS and Chukchi. I think the warm winter had the effect of dumping more snow on the pack than we saw in previous years. This has a lot higher albedo, retarding initial melt, but once that protective covering is eroded, the underlying thinner ice is melted more quickly. Not really sure which way to go this year because of the confounding factors. I don't think big domes of high pressure are going to necessarily get the job done in the melting department though. Wind and sun is really needed to take care of the snowpack and weaken the inversion and break the low level cloud cover that sets up as a result.

12Z EC pretty much goes nuclear.

Still a pretty decent gap there. Upcoming D3-D5 pattern look conducive to the development of widespread ponding pretty much basin-wide. Pretty similar to the 2012 pattern, just a couple of days later in the calendar, with the addition of the Atlantic side getting hit at the same time. Depending on how long that pattern lasts, we could see a pretty quick swan dive in area/extent/volume figures. The Pacific side is particularly weak and thin with FYI this year and it'll take less to demolish that ice cover than it typically does.

2012 cliff started in a few days. It looks like the forecast is pointing towards increasingly hostile conditions in the next week (recent model skill caveat applies here) which might give that 2012 dive a run for its money. 2017 is starting with less ice in the Chukchi, but more in the Kara and Barents. Preconditioning is somewhat less this year, but the ice is notably thinner due to warm winter weather. It'll be interesting to see how this plays out as we head into the most critical period for ponding.

Area tanking fast as melt ponding sets up. -157k yesterday and -117k. Now in 2nd place behind 2016. Kara/Barents look to be getting hit, with some contribution from the Beaufort and Hudson Bay. Model skill scores are still in the tank and generally unreliable past D4 right now, but they do more or less show more widespread warmth continuing through the next 4 days. The EC is suffering less than the GFS is, but still taking significant hits to its scores.

Stable 5-wave pattern showing up on ensembles now for the first week of June. That leaves the door open to ridging over/near the pole but doesn't guarantee it.