Thread by @althecat

Not sure weather assembly is a technical term. But I think it should be. As in "this #Don weather assembly in the North Atlantic is extraordinary visually. https://t.co/1ijtyIZdzb

Closeup from this evening.

And another one.... this time showing impact on Western Europe.

And overnight last night. The low remnants of #Don remain remarkably stationary north of Ireland and West of Scotland, but appear to finally be decaying.

In the top right you can see an arctic blast coming south over Finland.

Judging by the observed strength of the rain that passed over Brittany a few hours ago (tropical warm rain fairly persistent) the modelling of this weather event could be estimating its impact on the low side.

Update.... this is a very impressive weather phenomena. The size and strength of the low circulation over the UK is remarkable. As is the atmospheric water flow both over the UK - sweeping down around the low but also coming north over Spain and the Western Med.

This Arctic storm over Finland is also very impressive. The reason it appears to be oblong in shape is due to the curvature of the earth. The storm itself is probably circular.

While its an arctic storm in origin. It is also being powered by an atmospheric river bringing it moisture and energy as the water vapour coming north is warm - and interestingly as you can see here it is actually coming from the North Atlantic too.... its all part of the same… https://t.co/CpDFVcVqQjtwitter.com/i/web/status/1…

This animation shows the evolution which is both complex and huge and possibly hazardous. Remember that the exact energy levels in these ARs are hard to determine accurately.

At the beginning of the animation you can see the low pressure system which has been driving all of… https://t.co/iHpyPIEYA0twitter.com/i/web/status/1…

The outcome of all of this will be lots of rain over nearly all of Europe north of the Mediterranean - with light rain along the Northern Med. coastline.

The risk of their being localised extreme rain events causing dangerous and destructive flooding in the progression of this - especially over the next five days - is imo fairly high. The large scale model shows peak rainfall at any specific location at 30cm. But this does not… https://t.co/IQATOnEzYQtwitter.com/i/web/status/1…

Here is the current meteoalarm warning picture. The UK is excluded because its not in the warning system anymore, not because its not going to get any extreme weather.

There are multiple localities here which will receive over 200mm and the map total peak is 33cm a little over one foot of rain.

/continuing story....

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