Interitus

Unfortunate that every time he links that paper on the back of a couple of GFS runs into far long range, the forecast promptly evaporates as quickly as it appeared! There's a lesson there....

Not really, the northern extent of the Antarctic peninsula is exaggerated by its proximity to the Weddell sea which reaches much further south (though is frozen most of the time so is effectively 'land') there are parts of the eastern Antarctic which are also outside the Antarctic circle. Nothing to do with map projection, Marambio base on Seymour Island is at 64°14' S, nine degrees south of Cape Horn. The equal distance further south at 73° is well into much of the mainland. Marambio is also marginally closer to the South Pole than Nuuk / Godthab, the capital of Greenland is to the North Pole. Is Nuuk not part of Greenland proper? What also must be remembered is that the most extreme cold is at high altitude from sites such as Amundsen-Scott (South Pole) at 9300 feet or Vostok 11,400 feet. In that regard similar to Summit on Greenland at 10500 feet and, incidentally, just shy of 73°N. Whatever, Marambio is substantially colder than Nuuk, mean daily temperatures are below freezing all year round. The last fast ice round Seymour island retreated this year after mid-January, the equivalent of mid-July in the northern hemisphere would be well into the Arctic circle, and now at the end of summer ice floes still circle the island. As such, a temperature reading above 20 degrees is notable regardless of how the significance of a single Fohn event is viewed. However, the Antarctic peninsula has warmed, with the associated reduction and loss of ice shelves eg Prince Gustav, Larsen A etc. And it doesn't have to be representative of the whole continent to be the highest temperature recorded any more than the cooler parts of the UK were represented by Cambridge last year for example.

The 19.8°C was from Signy Island. Seymour Island is only little over 40 miles from the Antarctic mainland, but further south than the tip of the Antarctic peninsula - so actually it's Antarctica which is closer to South America than Seymour Island, go figure.

It should do, assuming the global model providing the boundary conditions performs accurately.

Double post

The lack of any deep cold as opposed to surface inversions has meant that the high altitude sites of Aonach Mor and Cairngorm achieved their minima of -9.0 and -9.1°C on the morning of November 13th. The incessant wind probably helped too.

It is because planetary waves are better able to propagate upwards in a 'properly' formed vortex with a typical structure and vertical wind profile than one that has previously weakened and recovers which may have layers of negative wind shear acting as a barrier to propagation.

In December 2018 the polar ozone increased with the wave driving prior to the SSW but when this occurred at the start of January the ozone shot up to record levels for the time of year - https://ozonewatch.gsfc.nasa.gov/meteorology/figures/ozone/to3capn_2018_toms+omi+omps.pdf A paper currently in review (not yet published) examines the 2018/9 ozone season describes this, from the abstract - https://www.atmos-chem-phys-discuss.net/acp-2019-1093/ Incidentally, you are trying to find signs of the SSW in the average >80°N surface temperature?

The tweet is fairly clear, as posted earlier in the thread, the ozone distribution is a response. It spread out last year because there was a SSW.

That's a very specific estimate!

Not necessarily, in fluid dynamics it is possible to have negatively buoyant plumes. For example, the process of brine rejection during sea ice formation releases colder, denser salt water into the warmer sea water creating a brine plume. It's just the vertical fluid motion of one density material through another, but as pointed out has been used to refer to something in particular in meteorology. Though note in the US it is occasionally used with moist warm air from the Gulf of Mexico etc.

It hasn't just predicted climatology though, it's predicted an anomalous westerly season.

-26.7°C

A review of the 2018/9 stratosphere by Simon Lee and Amy Butler (free access) - https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.3643?hootPostID=e556789f8449e0151927809065bece99

Dennis the menace

Away from your corner in the southeast, that's debatable!

At the moment the 0.4 mb level ranges from 52.37 km high at the North Pole to 56.52 km at the South Pole - the effective earth polar radius increase is 0.89% (the maximum, earth oblate, tropical radius greater) equating to an effective area increase of only 1.78% compared to the surface.

Areas of low pressure form in the lee of the southern Greenland topography with a Greenland tip jet focusing winds and associated baroclinc zone. A low level feature, here are the winds at 850 mb at midday Monday - The tip jet missing at 500 mb with the wind reflecting the broader upper level jet structure - The 500 - 850 mb wind shear showing stronger winds closer to surface in tip jet -

As suggested last week Yesterday 1mb wind < 6 ms vs 10 mb wind 24 ms - negative vertical wind shear giving reflecting surface for wave 1.

Greenland tip jet forming - Extending downstream - Detaches, heads towards UK -

36% less damaging, wind drag proportional to square of velocity.

Just to add to the Oslo snow thing, if it makes a difference, the airport is 23 miles inland from the city and at 208 metres vs sea-level

Don't forget in the deep lows the 850 height is much lower, the temps don't need to be as low.

Is the stratosphere colder all over though? Not checked the data yet, but the strength of the vortex depends on the meridional temperature gradient - if it cooled more at lower latitudes for example, the tendency would be towards a weaker vortex.

There, fixed it for you.