Hi all,

Here's today's longer-range video update;

Chilly December On The Way?

http://www.gavsweathervids.com

Thinking we may have rather a lot of frost/fog?

Quite large downgrade today with that bearing high being pushed into canada instead of being allowed to establish over the central arctic. 

I fear that sensible idea may fall on deaf ears in some quarters.

What is a "bearing high"? Or are you referring to the Bering Sea?

Despite conflicting views from members of the forum I personally reckon there is enough interest to be had in the longer term.

http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png

neil, i dont believe there have been any improvements to the gfs op. i think that will be some time in 2014.

tbh, the recent 'debacle' should have been easy to foresee using the extended ens and the spreads. the naefs fi was consistent in showing a large cluster around greenland. my mistake in assuming that meant a block. it generally does but in this case, had i done the maths, it was clearly showing a depression.

all in all, it appears gfs was better as it didnt go for the uber amplification of ecm. however, it was too flat. the probable end judgement is that neither did themselves any favours and it was probably a draw. the lack of a cold amplifed pattern makes us think gfs did better but i suspect the truth is, as often the case, somewhere in the middle.

looking forward, there is strange ens agreement on a decent mid atlantic ridge and scandi trough approaching the end of the frst week december. sustainable?  depends upon the polar profile.

There is a hint at something going on IMO

I agree - 50%+ of members go at least sub -7c over the period. 

That certainly isn't mild.

I like both  and nice women

Well the 12Z GFS run is proof if it were needed that one was never take one member of one run in isolation.
Without seeing the ENS set I can't comment on where it fits and if it continues the recent trend but taking the OP in isolation doesn't look very inspiring for cold weather peeps.

as the cold cupboard is bare< some FI comfort for coldies


http://www.wetterzentrale.de/pics/Rgem1921.html

 Check it out at 240 too

 Its similar to this morning's ECM.  A gambler would call a cold snap for 10 days time.  Im not a gambler.

Yup never quite gets there on the Op - everytime it looks like it's going to produce a bit of eye candy it winds the PV back up and shunts everything south and east. Looks chilly over Scandi etc though which isn't a bad thing.

Interesting little cluster of cold runs right out in FI - presumably there's a weak background signal for cold air to end up over the UK at that point. Worth keeping a vague eye on to see if it develops the theme I guess. 

Could be a frustrating few days of model watching if it's cold you're after, although as the GFS demonstrates in the mid term always a chance of a glancing cold strike giving a few days of colder weather and the chance of some wintry stuff.

Edit: http://www.jp2webdesign.co.uk/two/ensembles/

Being picked up by the ECM this morning and GEM this evening, but only the likes of  Jonathan Powell and his mates in the press would say that was a definite at this stage.  If you gamble enough times, you will hit the jackpot once.

Back-end northerlies do seem to be the main source of snowy potential over the next few weeks, although there are a reasonable number of runs developing disturbances in the flow with high pressure ridging over the top, leading to a bit of easterly weather as well.

It sure is a mobile setup, but this is the time of year when that's usually at it's peak, which is why I'm not too bothered by it.

Sometimes I do love the GEM when it gets carried away:

http://modeles.meteociel.fr/modeles/gem/runs/2013112212/gemnh-0-240.png?12

The Siberian PV goes crazy while a ridge amplifies to our west.

A key factor will be how often and to what extent energy crops up near/over Canada. It does look to be enough to keep toppling those amplified mid-Atlantic ridges... just need them to keep stabbing at the pole so that we can make some progress somewhere 

Depends which model you follow and whether your glass is half full or empty...

ECM agrees with the cooler/colder interlude for the end of the month and start of Dec, before HP settled back over the UK, presumably bringing a few more days of cold and frost afterwards.

Seems to be a repeating pattern of HP ridging to the North before retreating back over or near the UK and setting up for another go - just need a little less energy remaining in the PV remnants near Greenland and stronger HP ridging down from the Artic and the 2 day topplers might get a little more interesting.

http://www.meteociel.fr/modeles/ecmwf/runs/2013112212/ECH0-240.GIF?22-0

A fair bit of cold blasting into Europe

Cheers Gav

Mild weather isn't a given yet then

ECM really going strong on that bearing high today. That 552 isopleth makes its way from the pacific ocean towards the arctic. Things are really getting interesting now .

Look at all that beautiful WAA of the coast of alaska. 

It will, I don't get why people are not looking at the bigger picture. The 500hpa heights on the NH are particularly good today. Ultimately unless that bearing high gets pushed into canada, sooner or later it will merge with greenland. The PV will drop towards scandanavia and we will get a cold spell. Whats going on in the atlantic, I really don't think is too important. Either the atlantic high will retrogress to greenland or will be buldozed by a scandi low. The key thing here, is the great synoptics being progged for the arctic. I think we just need to be patient to wait for it to translate to cold here. Idk, if this reasoning is okay, but it seems sound to me. If I've made a mistake someone tell me so I don't embarass myself further 

http://cdn.nwstatic.co.uk/ecmimages/20131122/12/npsh500.240.png

Look, today the ECM has the 564 isopleth over northern alaska! Its like the GFS was a few days ago, or perhaps a little better. 

Even more prominent on the anomoly chart

http://www.meteociel.fr/modeles/ecmwf/runs/2013112212/ECH101-240.GIF?22-0

And things are staying consistant, the GFS first picked this up at the 300ish mark, and the ECM has consistantly forecasted this for days. Still could be a major pattern change, but starting to get less likely. of course there will be a much bigger variation at the surface.