Interitus
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Posts posted by Interitus
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15 hours ago, Midlands Ice Age said:
Thanks Interitus… I have figured
If you choose the 'flat earth' projection I show below, then you may have a case.
In my comments I made the comment about the Antarctic continent landmass (remiss of me), and not the Western Peninsular stretching up for nearly 1000 miles into the Atlantic/Pacific Oceans.
The west Peninsula is an 'add on' to Antarctica from a weather viewpoint (IMO). It is a bit like saying 'that the Scilly Islands (and St Mary Island in particular) is representative of Gt Britain.
If you use a much better projection of the area that I show below, you will see it is much closer to the Southern America,(with a scale and realistic projection to match), than to the main Antarctic continent. Yes it is only about 25 to 50 miles from the Western peninsula, but so is St Mary's from the Silly Island!!! Also St Mary's would never claim to be representative of Scotland (also about 500miles away) ~ maybe just of the Scilly Islands?.
MIA
Back later with the Masie news
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.
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On 06/03/2020 at 10:58, Midlands Ice Age said:
In your post (link) it says the highest recorded on the Antarctic continent was 19.8C recorded in Jan 1983. I had read about that somewhere and I was going to try and find it. So previous claims (about the same date in Feb 2020 (of this new claim ) of an Antarctic record of 18.3C were false. I must say I think I had also seen 18.9C mentioned somewhere also.
It would seem that (about the same time) Seymour Island had recorded this 20.7C, and so they are now pushing this as the new record due to the dodgy nature of the first claim..
But.. 1) this island is as close to South America as it is to the Antarctic continent. Its like the Faroe Islands are to Scotland and Iceland, or more likely Madeira and Spain.
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.
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59 minutes ago, Nick F said:
As it is a short range model the UKV is run at higher horizontal resolution than EC and GFS, so perhaps why it could be doing better at short range with more mesoscale features.
It should do, assuming the global model providing the boundary conditions performs accurately.
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On 19/01/2020 at 13:55, damianslaw said:
I seem to recall winter 15/16 produced the lowest min of the 'season' in November? Correct if wrong. In 2001 the lowest min occured in early March, a very low -21 degrees from a northerly.. Not often happens the lowest min falls outside the three winter months. Lots of time left yet to beat the Tulloch Bridge figure.
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.
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1 hour ago, mb018538 said:
I don't understand your point here? Dr Butler is just stating that from available data, if there is no SSW/PV disruptions in a winter season, we are more likely to see a dynamic early final warming. She's not saying 2020 will have an early warming at all, it's just more likely from past data. As she is a world renowned expert in the strat area, I'd take note of her thoughts!
My understanding is that seasons without any PV disruptions tend to have much colder temperatures over the pole and a tighter/stronger polar jet locking everything in place....so when the balance tips and the warming starts to happen, the collapse is just that much stronger that it can't recover. The bigger they are, the harder they fall and all that.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.
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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 -
QuoteIn winter 2018/2019 a major sudden stratospheric warming (SSW) took place with the central date at 2 January. We present the ozone, water vapour and wind measurements of the winter 2018/2019 and discuss the signatures of the SSW in a global context. We further present the evolution of the ozone gradients at Ny-Ålesund and link it to the planetary wave activity. At 3 hPa we find a distinct seasonal variation of the ozone gradients. In October and March a strong polar vortex leads to ozone decreases towards the pole. In November the amplitudes of the planetary waves grow until they break in the end of December and an SSW takes place. From November until February the ozone gradients mostly point to higher latitudes and the magnitude is smaller than in October and March. We attribute this to the planetary wave activity of wave number 1 and 2 which enabled meridional transport.
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?
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39 minutes ago, Midlands Ice Age said:
Thanks for the above KW...
So the Ozone levels and their distribution can show whether or not the PV is going to/ or has 'ramped' up?. It is a question of which comes first? I certainly was reporting the different Ozone distribution this year earlier on than when the PV formed.
Whereas, last year the Ozone just 'spreadout' over the whole Arctic in early December. A totally different signal.
However all fairly anecdotal, a similar year would be interesting. - It probably is worth watching in future years.
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.
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14 minutes ago, knocker said:
with winds gusting between 50 - 50mph at a guess
That's a very specific estimate!
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1 hour ago, Radiating Dendrite said:
A plume is something that rises by definition, so in this instance, I do not think it is correct to use.
Cold air sinks and generally comes from the north (or east). A submersion of cold might be better
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.
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16 minutes ago, mountain shadow said:
It is of course far easier for a model to predict a predominately Westerly driven season when our weather comes predominately from the West. The proof of Glosea5's prowess will be in predicting a colder Winter and whether that actually occurs.
It hasn't just predicted climatology though, it's predicted an anomalous westerly season.
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2 minutes ago, snowblizzard said:
Wow, that's intense!
What temperature would you expect from that at 2 metre level?
-26.7°C
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A review of the 2018/9 stratosphere by Simon Lee and Amy Butler (free access) -
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Dennis the menace
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21 minutes ago, Atmogenic said:
But the obvious difference with summer isn't that there is a temperature difference but the sun. The sun is the main source of warmth in the summer so it covers the entire country
Away from your corner in the southeast, that's debatable!
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3 hours ago, Singularity said:
The upper stratosphere is always difficult to model, due mainly to the resolution issue; as one moves further from the Earth's surface, it takes more and more of a certain size of grid box to cover a region. This tends to hold back the resolution of the upper-stratosphere layer(s).
That's a particularly large reason to be cautious with stratospheric projections past 10 day's range .
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.
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5 hours ago, knocker said:
By Monday Ciara is well clear to the north east leaving the UK in a much cooler and unstable airstream with gales persisting, particularly in the north. Thus the potential for frequent heavy and squally showers, particularly in the NW and these could well have hail and snow in the mix A glance at a forecast sounding indicates Cbs possibly up to around 20, 000 ft. There is also a chance of more persistent rain as a frontal system nips through
A not dissimilar day on Tuesday
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 -
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5 hours ago, knocker said:
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.
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Greenland tip jet forming -
Extending downstream -
Detaches, heads towards UK -
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25 minutes ago, fujita5 said:
Those gusts are 'worst case scenario', i.e. the strongest possible gusts in that particular modelled setup. So they are very unlikely to verify, if they did they would be very isolated and probably associated with strong convective downbursts.
HOWEVER... if 120mph was being modelled then even a 20% reduction in actual speeds would be very damaging!
36% less damaging, wind drag proportional to square of velocity.
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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
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53 minutes ago, Singularity said:
Some words of caution for any snow-seekers taking the GFS precipitation type charts at face value during those polar maritime incursions - it has a low temp bias past a couple of day’s range, which from studying it’s performance, tends to be strongest in that setup.
Worth paying more attention if & when ECM shows sufficiently cold conditions within a week’s range. Or, I suppose, if GFS goes some way beyond the min requirements e.g -10*C 850s. Not out of the question for Scotland if one of those big lows moves in the right way and intensifies once already level with the UK (as this means less mixing out of cold during approach).
Don't forget in the deep lows the 850 height is much lower, the temps don't need to be as low.
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19 minutes ago, Singularity said:
Uncertainty over how much the MJO will gain amplitude in phases 4-5-6 in the coming fortnight.
In Feb, 4-5 destructively interfere with the climatological Pacific and Atlantic ridges to varying degrees. So we’d be looking for internal events for vortex weakening beyond the season trend - which itself is likely trending stronger for longer as the GHGs block troposphere-stratosphere longwave radiation (so in answer to the question from oasis, I expect yes, colder stratosphere and stronger polar vortex tendency).
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.
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1 minute ago, Nick L said:
Bring on the first high-teens temperatures of
MarchFebruaryThere, fixed it for you.
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Stratosphere and Polar Vortex Watch
in Spring Weather Discussion
Posted
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....