I wasn't being entirely serious. But Krakatoa supposedly caused colourful sunsets around the world, even in the UK, so I guess if it's high enough altitude it can cross the equator. And of course CFCs, largely from the northern hemisphere, migrated to Antarctica to cause the ozone hole.

Last year, two rather modest eruptions (Russia & New Guinea) reportedly led to some spectacular sunsets in the UK.

And whilst Krakatoa did bring widespread amazing sunsets, the most famous one was Tambora.

?? Go back another decade and almost 50 % of them in the last 50 years or approx 20% of the period covered. Lack of snowfall in the last 50 years is even more striking.

During January I look at the long term mean 850's at -3C and think that in almost any other month we get -5C below average at some point but rarely in January!!

ECM right at the very end of the run builds a Scandi High with low pressure over the eastern part of Europe. Perfect synoptic for a cold blast. Just need this to move forward to 24 hours then. Nailed on! 😂😂😂

Beat me to it. Best ECM chart for weeks, bit sadly right out at the very end of the run. Nice to see all the same.

The ECM Op is pretty similar to a couple of the GFS members. A couple of the members have toyed with Scandi HP rises in mid/long range FI for a while which isn't unexpected with HP about but generally they've had the jet just shoving the HP south and leaving us on the mild side. 

As you say though the ECM nice to see if nothing else, even if odds are rather high on it being totally different by the morning.

Have a look at P1 and P6 for GFS 12z easterlies - P6 even brings one of those vanishingly rare battleground snow scenarios. Sadly on their own really although a few other members have HP just that bit further south.

A few crumbs of comfort in an otherwise pretty boring period of model watching

Yes and look at that phenomenal cold pool out to the east... even a couple of small spots below checks notes -10C at 850mb over the Baltic  

thos Synoptics would get cold very quickly and in that set up below temps in south UK

couid do, but apparently Norway is experiencing near record high temperatures- BBC report 

“Western Norway is experiencing a rare heatwave for early January, at a time when temperatures should normally be below freezing.

The highest temperature of 19C (66F) - more than 25C above the monthly average - was measured in the village of Sunndalsora.

This makes it Norway's warmest January day since records began.”

that is now the lead up would create a very cold flow. January gets very cold quickly

As Neil mentioned there's a tendency to build heights to the N into Scandi at the end of some of the model runs. JC's tweet however was based on an out-of-kilter GEFS suite that really looks desperately unskilled now compared to the main OP run, and has done through most of the winter so far.

It's only when you see the GFS Op and more importantly ECM coming round to the idea that I'd take it anywhere near seriously - ECM is clearly now toying with it in the far reaches, but it may well be a rinse and repeat operation as the models toy with what has been very conflicting signals thus far. 

As for some comments on QBO easterly recently - I don't see that at all. It's been opposed or sheared on vertical profiles, potential filtering down easterly to lower heights through Jan.

Next thursday might challenge that.... both in norway and UK

https://en.m.wikipedia.org/wiki/The_Scream

absolutely something to watch. 

Yes, we're in autumn, the season that lasts 10 months of the year, from August to May.

Even in two weeks the reliable charts won’t even cover the end of January. We can still see wintry weather into early/mid March.

There really isn’t anything exceptional in the charts and mild weather is more a part of our winter than cold.  Mild and benign is less common but therefore more noteworthy.

ECM 12z ensemble for London certainly doesn’t scream wall-to-wall mild conditions

Some optimism in here last night but GFS is having none of it - continuing zonal, a bit of SW stormy stuff around the 13t/14th, then back to a continental high in just the right place (or wrong place, if you prefer) to pull up southerly airflow by Sun 19th. The temp summary shows cold air retreating ever further east www.wxmaps.org/pix/temp4.

ECM on same tack though it has the gales a bit earlier and has quietened down by the 12th (end of TWO display)

GEFS consistently mild to about 9th Jan in the south, temps up and down in the north but nothing really cold, then everywhere settling down with most runs a degree or two above average to 19th Jan. Some rain in N & W, not much in the SE

There are a few perturbations with blue near the UK but well out in FI - it might take you 5 minutes scanning the postage stamps before you find one!

In Gavin P.'s last video which he released yesterday, he showed us the latest GFS ensemble for here in Edinburgh at that time. In response to that, I thought that I would post the latest GFS ensembles chart from here on TWO to show how the overall outlook has been updated since then.

In the above chart, we can see that the upper air temperatures briefly get a bit colder than average for a day or so before getting warmer yet again (though not to the same extent which I have recently seen on these charts for other locations which are further to the south). Beyond that, we then go into that zonal sine wave pattern which Gavin P. referred to in that video before everything levels off in the more unreliable time. This averages out at just above the LTA although there is a lot of scatter there which indicates the uncertainties which there are at more than a week or so out.

As for rainfall, the outlook appears from the above chart to be dry for the next few days before becoming more unsettled, and that was how Gavin P. described that in yesterday's video. One thing which was on Gavin P.'s chart which isn't on the above chart of course, is the the spike at the beginning which was yesterday's rainfall. That seemed to go up to around the 5 mm mark but in practice, we ended with just 3.4 mm from that at at Edinburgh Gogarbank along with 2.4 mm at the botanic gardens in Edinburgh which is slightly less than that spike on Gavin P.'s chart had predicted.

Furthermore, the above rainfall spikes for later on don't look as convincing as the ones on Gavin P.'s chart, although Gavin P. has often said that the new charts which he uses for that tend to overdo those precipitation spikes. Because of that, I'm still not convinced that it will actually become as unsettled as what Gavin P. had indicated in yesterday's video especially since most of those rainfall spikes are in the unreliable time frame with quite a lot of scatter.

From that, I therefore stand by my opening comment in this month's PW thread where I predicted that this month could well be our first drier than average month overall since last April although the above chart only takes us to just over halfway through this month and there is no telling what will actually happen after that. What I do know though, is that there are still no real sign of winter from the above chart although there are some ensemble members which go a bit colder than average at times in the less reliable time frame.

How do you like your mild? Mild, very mild or unusually mild. Take your pick.