swebby

And on top of this - To me, it always seems that when a breakdown/battleground is forecast, the models inevitably go for fronts quickly intruding into the south west, thus suggesting snow initially for Cornwall/Devon/Dorset, when what actually happens is a slower affair allowing the cold air to be mixed out before the precipitation gets going, end result - cold rain.

Looks like a Foehn effect from the Easterly? Foehn effect WWW.METOFFICE.GOV.UK The foehn effect causes warming and drying of air on the lee side of cross mountain wind.

I tend to have a view the GFS dartboard lows are that model knowing roughly where the energy will be in regards to cyclogenesis but not knowing how to resolve it into a complex pattern of separate low pressures that eventually do manifest in that model in shorter time frame. So it takes the simple option of dumping the cyclogenesis onto a single point. In this instance, with that high pressure to the north, i would assume (probably naively) that if it is a complex system of lows, it would be in the form of disruption - with a train of lows being ejected and heading SE (sliding) under the block?

I'm not john i'm afraid but those spikes are on the meridian, so it looks to me like an artifact -a glitch in how the graphics have been rendered in order to show a hemispheric representation. Occasionally see this with other models along the meridian.

Not unusual early doors from an easterly set up. We will need the easterly to become established then a low (or lows) to come from the Atlantic and "slide" south east, Southern Ireland down into France. That can be produce a lot of snow especially for Southern Ireland. If you get a low that is just the right amount south and runs west to east through the channel (Channel runner) that can be an absolute dumping for the SW/ Southern coastal counties and Channel Islands, but that's a rare beast.

They have also had/having some very warm upper air temps across the Pyrenees and Apls - upcoming avalanche issues?

To be even fairer, it's the UK weather that fails to deliver. The charts could say snow in the UK at day 8-10, and inevitably the weather delivers snow 8-10 days later - but it's in Athens or Lisbon or Rome........

That thermal gradient over central Europe in your second chart - would that not encourage low pressure to form in situ over Italy and the Adriatic?

Except inevitably for Exeter and East Devon....... Could anyone explain that please? It's happy to show snow in the Bristol channel and for parts of the English channel along the same longitude. Is it Dartmoor resulting in a Fohn effect?

You timed that question well, just as an Easterly appears and distracts everyone! In theory you could make a crude estimate based on a standard lapse rate. Look at the emagram on this wiki page and you can trace along the lines from a starting temperature for one altitude/pressure to another based on it being a moist or dry air mass. Lapse rate - Wikipedia EN.WIKIPEDIA.ORG I've linked also to John's page on skew T's that was archived that explains lapse rates. Of course, you need to know if it is a dry or moist air mass. John will be able to better advise if you drop him a PM. If memory serves, the likes of Steve Murr and @bluearmy were good at advising on lapse rates depending on the source of air shown on a chart.

Also different with the low coming off the US's eastern sea board.

Would that be a good example of the finger print of an Omega block sat between the UK/Iceland?

In what has been a weird year. This would possibly cap it off nicely! Scientists looking for aliens investigate radio beam 'from nearby star' | Space | The Guardian WWW.THEGUARDIAN.COM Tantalising ‘signal’ appears to have come from Proxima Centauri, the closest star to the sun

Apparently they were initially given the acronym WTFs, sadly now changed to OCRs - Odd Radio Circles.

I know this is the hunt for cold thread (i've no problem with that) so this will probably get lost in the noise but a question for the likes of those trained in looking at these charts, e.g. @johnholmes etc:- Having looked at the 0Z ECM output for post Xmas, and using Day 10's post above of the GEFs at the same period as an illustration. Would this low that forms off the eastern tip of Greenland and then, whilst deepening, drops down into the North Sea ending up between East Anglia and Holland be a major flood risk for Eastern England and the Low Countries? I want snow as much as anyone else on here but to my untrained eye, some of these charts look particularly worrisome for north sea coastal communities?

Honest Qu as i have only a very basic understanding of the QBO. Is it genuinely totally unlike anything we have seen before? It seems to me to look a lot like 1989-1992, other than <20mb region being rather non descript, or is that the key region?

I'm not sure it matters? In that, if coupled, the strat vortex can only help drive the trop vortex, it's absence due to sudden warming means no driver. Basically the engine is turned off so it does not matter if the clutch is engaged or not?

I will go with a re-run of a cold wet December 2009. CET - 3.1 Ppt - 109mm

Some of the ones i'm trying to remember in regards to extreme NE forming storms, that is the ones that meandered around the Azores switching between tropical and extra tropical and back to tropical i believe did retain the name. Edit - Leslie 2018 is one of the ones i'm thinking of non tropical low -> sub tropical low -> sub tropical storm Leslie -> subtropical depression -> extra tropical low -> subtropical storm Leslie -> TS Leslie -> Hurricane Leslie https://en.wikipedia.org/wiki/Hurricane_Leslie_(2018) 2nd edit - Harvey 2005 is another. 2005 was also a year for some very north easterly formed storms like Vince.

Oooo, good catch Jo, i'd forgotten all about Pablo. It still took on sub-tropical then tropical characteristics while south west of the Azores, i'm wondering if there is anything that became a tropical cyclone between Portugal and the Azores, especially if the initial depression had originated from the NE?

Ah yes! Red sun and the end of the world! Orphelia did at least gain tropical characteristics south of the Azores, if that advisory pans out (low chance) then i would assume this could be the most northerly formation in the eastern Atlantic by quite some distance. Just looking up medicanes and i was not aware that the NOAA did actually designate one a TS in 2011 (Rolf) https://en.wikipedia.org/wiki/Tropical_Storm_Rolf

Just how often does this happen exactly? I can think of one or two tropical storms/depressions that have meandered about the Azores, headed north, become ex-tropical and then head back south and become tropical again. I think last year there was also a depression that headed off Novia Scotia and took a southerly enough track to become a very short lived TS. But formation off the coast of Portugal?

A link to the story in Astronomy Now https://astronomynow.com/2020/09/14/possible-evidence-found-for-life-on-venus/ RAS link https://ras.ac.uk/news-and-press/news/hints-life-venus The nature paper - no longer pay walled? https://www.nature.com/articles/s41550-020-1174-4

RAS currently giving a presentation on the discovery of phosphine in the atmosphere of Venus - this, like molecular oxygen is a key biomarker gas (an indicator of life). https://astronomynow.com/2020/09/14/watch-todays-major-announcement-from-the-royal-astronomical-society/

Just sticking this astonishing GOES snapshot from the NOAA in here. If there were anymore in the Atlantic we'd have to start to dob them in for breaking "the rule of six"!