csnavywx

Record low volume was 2016 (a near tie). Please tell me I'm misreading this and you're not trying to go down this "it's mostly natural variability" road.

That coffin has so many nails in it there's virtually no more room to fit another.

1 hour ago, SnoSki14 said:

The upcoming pattern is an absolute ice destroyer, massive blocking high over the Arctic. 

Extent will plummet late June into July. 

https://www.esrl.noaa.gov/psd/forecasts/reforecast2/teleconn/forecast.html

Some of the area flatline is due to cooler weather, but some of it is also due to melt pond draining as water-covered ice tends to be (incorrectly) counted as open water by the sensor. There tends to be a big drop initially as widespread melt ponding sets in, it rebounds somewhat as those ponds drain and then drops again as the ice breaks up.

The Chukchi-Laptev sector has been under withering fire for some time now. If this keeps up, there won't be an ESS "arm" of ice to be recirculated this year. About the only spot that's in halfway decent shape appears to be right near the pole. Some ponding there, but not too much -- yet. Ponding isn't quite as widespread as 2012 overall, but the open water fronts are generally in a more retreated position, with the open front from the Beaufort-Chukchi being opened very early and the Laptev bite being especially large and the fast ice and poleward pack ice in an advanced state of decay already. The Atlantic sector is in better shape than 2012 at this point and I think that's where most of the extra area/extent is located right now.

This year has a legit shot of seeing full open water at the pole, if nothing else due to the advanced state of the Laptev Bite.

One thing that does concern me considerably (for this year and future ones) is the amount of heat being pumped into the Chukchi. It is running extremely warm (4-8C SSTs already) and that water tends to be pumped under the halocline where it is stored from year to year. Once temps reach ~12C though, surface density drops below the fresher water at the top of the halocline, allowing it to be disrupted. It doesn't take a full disruption though. A weakened stability gradient is enough to cause some significant changes. So the heat pump that is running in overdrive this year will only serve to hasten the demise of the summertime Pacific sector in the future.

21 hours ago, forkyfork said:

he'll disappear in about a week

Yeah, some of these ensemble and OP runs are pretty monstrous with the heat in a few days.

The aggressive final warming of the PV in late April seems to have done a number on the pattern this year. It's shaping up to be much closer to the 07-12 pattern than we've seen in recent years (with the possible exception of '16). The Beaufort and Chukchi are in record low territory already (by a long shot) with a continuous open water front establishing very early in the season.

It's been very warm in May, though slightly cooler than 2012 as of the last week or two. That could change over the next 5-10 days as a big Greenland block looks to get going and the EPS and FV3 hint at what could turn into a big classic dipole by mid-month. It'll be warm until then, so losses should continue apace, but some real fireworks would get going if that verifies. This year's tendency has been strongly towards blocking, and I suspect that dynamic PV breakdown this spring has something to do with it. Unlike the last several years, where we would slide inevitably into a PV-dominated pattern, that does not seem to be the case this time around. These blocking patterns have actually been verifying.

Diffusion of heat down the water column via mixing or and/or subduction under a vertical salinity gradient. Stronger winds will increase the depth of the mixed layer, bringing up colder intermediate and (in some cases) deep water to mix with near-surface waters, for instance. When combined with increased heat uptake due to GHG (and other) forcing, that causes said heat to be "buried" at depth, even though surface waters may cool. This can give the illusion that the extra heat is gone, but in reality, it has simply been mixed or subducted down. The situation can change if the circulation state (via natural variability or otherwise) changes, allowing some of that heat to effectively resurface.

15 hours ago, Maestrobjwa said:

What does that mean, exactly?

Not much. SOI is a lagging indicator, not a leading one. U-wind anomalies in the Trop. Pac. (particularly west and central) can tell you quite a bit more about where ENSO is headed.

3 hours ago, bdgwx said:

Preliminary numbers show that the annual mean extents for the NH finished second lowest behind 2016. SH was similar...it finished second lowest behind 2017. 

The SH is whole different beast, but the fact that we had 2018 end badly lends a bit of credence to the idea that 2017 may not have a fluke. I wonder if we're beginning to observe the paradigm shift down there too. Any thoughts csnavy?

It's possible we've turned the corner down in the SH, but it's hard to say with only 3 years. Some of the bad conditions this year are undoubtedly just weather. However, the reappearance of stronger deep convection (for example, -- Weddell Sea polynya -- after decades of absence) could mean that we're returning to a circulation regime less conducive to retaining sea ice in the melt season. A great deal of heat burial has taken place in the Southern Ocean over the past 20-30 years, so any relaxation of that pattern will of course allow some of that to resurface and augment the background GHG forcing.

Interestingly, this heat burial mechanism is occurring under the Arctic as well via transport from the Pacific through the Bering and under the Chukchi Sea into the CAB. It is also coming from the Atlantic via the Barents (where the intermediate warm layer has intensified rapidly and shoaled over time). Once that reaches critical mass (10-15 years), it too will surface and bite into the CAB.

14 hours ago, WidreMann said:

I don't follow SH weather patterns. What do you think is the cause?

Warmer temps, less clouds and unfavorable winds. The last 3 years have been pretty bad, but this one takes the cake with all of the early ponding and breakup.

The Antarctic season has been remarkably bad and is now dead last in both extent and by a large margin in area. It's also in considerably worse shape (concentration wise) than even 2016.

The difference between medicine and poison is often the dose.

Another insane autumn. Starting to see these open water areas stick around a lot longer into the fall now. It will be interesting to see how late the Chukchi stays open this year. That side has become a serious weak point for the pack during the summer melt as that region has transitioned well away from having any persistent ice cover.

Lost power for about 9 hours down here last night. Impressive winds most of the night. Measured ~40G55 nearby. Lots of lightning and very heavy rain. 3.54"

After a meager +17k increase on Jaxa yesterday, 2018 has now claimed 2nd place behind only 2012 (+619k). That was fast.

1 hour ago, bluewave said:

Very close to record warm temperatures around the North Pole for the end of September.

http://sites.uci.edu/zlabe/arctic-temperatures/

 

Records are going to get steamrolled for the next week or so.

3 minutes ago, bdgwx said:

Last night's Euro run was +4.25 SD at 168 right over the pole.

We've seen some nutty height anomalies over the Arctic at times in the past few freezing seasons, but this takes the cake. It's like taking the entire North Pacific atmosphere/airmass and ramming it into the Arctic.

Seeing some hints of an extended chinook event off the Kuskowim-Alaska Ranges and later the Brooks Range too. Definitely going to throw an extended brake on re-freeze. Might even see some drops (as Friv alluded to earlier).

That EC run last night -- oof. +4SD ridge. Even the EPS is +3SD at a week out with widespread +10-15C anomalies across almost the entire basin. The FV3-GFS is much the same. OP deterministics are of course even more extreme. This would be a pretty hefty ridge by mid summer standards, much less late Sep/early Oct.

Yet another year with an extreme autumn setup.

Especially if this recent winter warmth becomes a more frequent thing -- which is hard to tell at this point. The collapse in freezing degree days over the past 3 winters has been remarkable and has only been offset by remarkably good ice retention weather in summer. However, we're only about 2C away from winter temps causing melt season collapses almost regardless of summer weather (this year's collapse in the Beaufort sector despite otherwise cooler and cloudier-than-normal weather is a good illustration of that).

It's an extrapolation, but it more or less matches up with the middle estimate of the board members (2030s).

1 minute ago, weaponxreject said:

 

 

Per the "up to 120mph", definitely didn't happen sustained wise, and gusts were mostly in the ~100mph range, so the guidance wasn't off much for those on the coast imho. Agreed, the Cat5 talk needed to be toned down. Especially when, per the SS scale and keeping in mind the general public's knowledge, there isn't really a huge difference between a 4 and 5 wind wise, and one could potentially argue that after a TC reaches a 3 the Cat is irrelevant.

I understand keeping a balance. Idk, maybe I didn't hear/see any of the fear-mongering you're referring to because I was mentally balls deep in the meteorological side versus public side.

Per the climo though... I've seen it referenced over and over by experienced Mets and by weenies on forums like these that this wasn't a storm one could really compare to climo because of the stack of statistical anomalies involved. Were they all wrong? Were they all focusing too much on those outliers versus the larger synoptic picture, so to speak? I want all input and perspectives because it could very well be me one day writing a FD for dissemination by the NHC... Conversations like these matter, but the hyperbole from both sides damages the goal, I feel, of properly conveying threat to life and property.

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Climo wasn't a help with this storm.

Underforecast and underanalyzed shear in a shallow region under the outflow layer on the SW side of the storm about 2 days out from landfall helped disrupt the inner core just enough to bring it down a notch.

A cat 3/4 landfall was the best call at the time, given the data available. I'm not sure the surge or flooding problems would've been any less even without the weakening period though.

Frictional torquing likely playing a part in keeping it offshore. The torque component can become dominant in such weak steering flow and when running at a shallow angle to the coast (as Florence has).

3 minutes ago, psv88 said:

Cnn reporter in Wilmington which is supposedly in the eye wall now. Doesn’t look bad at all.

ASOS at ILM reported 56G91KT (62G105mph). Multiple reports of 100+ mph gusts along the coast to the east as well and sustained 80-90 just east/southeast of ILM.

Frictional convergence doing serious work as the eye tries to come onshore. It was able to spin down the outer wind maximum, which has allowed the inner eye to consolidate and contract.

That high level shear is really showing up well on IR and the 250mb charts now. However, as the NHC discussion stated, it abates between 06 to 12Z tomorrow. Until then, expect more weakening as that shear is now able to impinge directly on the core.

33 minutes ago, hlcater said:

 

I dont think the eye is 60-70 miles wide. It may look like it is, but recon did a little loop inside the eyewall. Unless that wasn't what you were using to judge size. Does anyone have a vortex message?

Ah, you're right, didn't see the loop. My bad for not double checking -- 25-30 looks about right based on the most recent pass.

Inner eyewall looks like it is gone finally. Still multiple wind maxes though.