Sadly (unless you want so much rain), there's a fair bit of support in the ECMWF ensemble for something along those lines.

Note too the long reach south-eastward, all the way to the easternmost Mediterranean, where some intense rainfall events look possible.

It's a weather pattern that can deliver some of the most widespread 50+ mm totals to western Europe.

Where the westerlies hit the mountainous terrain in northernmost Iberia, some pretty immense rainfall totals can occur.

In short, this scenario is one to watch out for.

At the same time, I can't see more than the slightest possibility of a scenario that would bring markedly cold weather to NW/N Europe within the next 10 days.

Maybe some chilly conditions at times, if we see a sluggish outcome.

Granted, the ECMWF ensemble is still heavily weighted toward those brisk westerlies, but I know from experience that whole ensemble sets can lean the wrong way when key complications aren't well resolved at the nearer timeframes.

So, I'm wary of presuming mostly mild & windy.

Importantly, this challenges recent consensus that the reflective type sudden stratospheric warming event would cause the jet stream across the Atlantic to quickly strengthen & drive brisk westerlies for NW/N Europe during early Dec.

Something more variable now seems plausible.

In Europe, this favours near to above average temperatures with bouts of wet & windy weather affecting the north / northwest.

In North America, it's a different story - see my blog for more detail.

If energy waves then continued to be absorbed by the polar vortex, we'd see the NAM index head negative across the 1000 to 200 hPa pressure levels late Nov into Dec.

Instead, those waves are forecast to be reflected, resulting in a mixed NAM response.

See how the polar vortex (marked 'L') is displaced toward Eurasia by an anomalous anticyclonic circulation (marked 'H').

As I mentioned in my latest blog published yesterday (www.metswift.com/2025/11/24/s...), this is a common layout for a displacement type event.

I also find it interesting that there are still a dozen or so runs that keep the zonal mean zonal wind below 20 m/s through mid-December, which implies a pretty weak polar vortex state.

Meanwhile, about as many bring it to near average strength. Not good for forecast confidence.

...with the signal for a rapidly recovering polar vortex holding fairly steady through 23rd, before being toned down a bit in the updates of 24th then 25th.

Yesterday's set began to hint that the polar vortex might weaken again in the 3rd week of December.

As a footnote, 0.1°C doesn't sound like much on the face of it, but the detrended ERA5 dataset has a range of 0.86°C from coolest to warmest year, of which 0.1°C is 11.6%.

If you suddenly grew 11.6% taller, you'd notice that a lot.

If an El Niño develops & becomes a moderate event, & does so soon enough or with enough further intensification for the annual mean ONI to be at least 1.0 (relatively low chance), then it appears the 2026 global mean temperature could also be nudged upward.

Looking ahead, there are good reasons to anticipate that al El Niño event will develop next year, & one with the potential to reach moderate (+1) or greater intensity.

Even if it stays weak, correlations suggest that could raise the 2027 global mean temp by ~0.05 to 0.1°C.

A more accurate statement is: "2025's mean temperatures aren't being pushed upward by an El Niño event".

This is still worthy of note because 2025 looks on course to be the 2nd or 3rd warmest on record.

wmo.int/media/news/2...

Beyond 7th December, the 'window of opportunity' for a pattern change that I've mentioned before continues to feature in the ECMWF ensemble.

~40% of the set develops high pressure either north of Europe (~30%) or right over Europe (~10%).

Just something to keep an eye on.