Been hinting at a change around mid month last couple of runs, worth keeping an eye on

Certainly continued tentative signs of a change in the 3rd week of Jan. 00z GEFS anomalies day 14

The NAEFS and GEM are less impressive though

Probably worth waiting until we get into the day 10 timeframe before getting too bothered.

Nearer to the present a nasty storm showing on the UKMO

So zonal express for the next 12 days at least with the chance of stormy weather in the North, then weak hints of a change to a more meridional pattern with the chance of getting some cold air from the North but very tentative ATM.

http://www.wetterzentrale.de/pics/Rtavn3481.gif

FI yes

Just need the HP to shoot up to Greenland , certainly seeing hints of a change mid month

http://www.wetterzentrale.de/pics/Rtavn3601.gif

Wintry from the NE

http://www.wetterzentrale.de/pics/Rtavn36017.gif

http://www.wetterzentrale.de/pics/Rtavn3604.gif

OK, another few runs and again the increase in heights to the west and NW Day 12 is still there. Infact GFSP delivers some tasty charts from +336 and the 00Z ENS had that dip again in FI
It is still very early to be raising eyebrows but it's much better than looking at the mild drizzle that's currently outside my window.

GFSP6z going for a genuine cold spell post mid month:

Indeed. The ECM control run also shows a colder spell from T+294 onwards, with an Icelandic high popping up by the end of the run (at T+360).

It's getting interesting now!

Every day I look the ensembles at 384 get more and more interesting, this strat warming seems to have a fairly big lag on it. 

GFSOP once again is a cold outlier

however there is a definite cluster that goes cold and starts to bring the average down. It seems to me that its going to be a fairly slow transition to cold (assuming it arrives) so we should continue to see the ensemble members get colder and colder.

Latest CFS V2 charts are showing tentative signs of heights building around Greenland............... In July.

Here we go again... having done some reading around it appears we're in a very similar situation to where we were in mid-December, with the MJO being projected by GEFS to progress into favourable areas for producing blocking around Greenland without collapsing, but the other models less keen on this.

Annoyingly I can't get an updated MJO outlook for today or yesterday for most models, so all I know for sure is that CFS was even more keen on the progression yesterday in its long-range outlook.

After last time I'm even more skeptical than usual of the longer-range GFS/GFSP signal at this stage.

At least this time we have some strat. warming on our side of the hemisphere to help reduce westerly momentum and sustain any heights building toward Greenland for longer.

There's also a very strong Siberian ridge being shown to build from day 6 onward, and on the 06z GFS and GFSP op runs we actually see this lifting deep cold out of the heart of the continent and sending it on a journey around the western flank of the polar vortex to pile into the Atlantic, this shifting the cold/mild boundary and hence the jet stream increasingly far south as the runs progress.

Key players in the 7-10 day period look to be that Siberian ridge - the stronger and further west the better - and the extent/positioning of low pressure development on the Canadian border of the polar vortex - too strong and/or too far west and we're waiting longer for the jet to dive far enough south in our slice of the hemisphere.

We should at least enjoy a bit of 'eye candy' in the near future if these trends can solidify.

Good news about the ECM control run as that suggests the model is considering a more favourable MJO progression and/or strat. warming impact as well.

If we can get it to phase 7 with ENSO in the current state (region 3.4 at an anomaly of +0.5 or greater) then the composite is this:

That's for low amplitude phase 7 on the left and high amplitude on the right.

It looks phenomenal for us BUT it's based on theory that as far as I know requires the Pacific SST pattern to match a typical El Nino pattern when actually we have had an unusual amount of warmth remaining in the western Pacific and interfering with things.

So the response may not be entirely in line with the above... assuming the MJO reaches phase 7 in the first place!

Definitely a change to colder weather on the way from Mid-month but will this hold and can these could GFS runs stay persistent and continue with the cold theme - even into FI!?

IMO around mid month onwards we'll see a pattern similar to what we experienced during the latter half of December with a displaced Azores  High and a trough over Scandi leaving the UK in a cool NW airflow, so all in all the rain will  just be colder down South whilst elevated Northern areas will see more  in the way of wintry precipitation. I just can't see a pattern change to deep cold anytime soon with SSW events having little impact for our neck of the woods.

Some posters falling into the trap of putting specifics on things 15 days out which is a recipe for disappointment.
Just take the general theme and median clusters and not single runs in isolation and accept that there is a small chance of colder synoptics for now would be my advice.

By the way, for eye-popping fun have a look at member 11 in the GFS suite. What is going on there LOL?

And for cluster analysis:
http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=306&y=141&ville=Londres

As strong a signal for 850s to head south later on as there's been so far.

I would agree with all that Neil however I would tend to use the word increasing where you have used small.

I would also add , that IMO people aren't taking these far out charts seriously , surely they aren't. But they are worth posting all the same just for trend purposes .

If they are still there Monday afternoon then the trend could become reality

JFF all of course

Yes, it's not a small chance IMO - and it's increasing.

I regard the ensembles as being the best thing we have when it comes to checking for pending changes in pattern type and the last few runs from both ECM and GEFS have shown the same thing - a trend towards colder conditions for the latter half of the month.

It reminds me very much of the last cold spell. ECM picked up on that right at the edge of its range and over the following two weeks more and more runs fell into the cold cluster. In the end it firmed up on around a week's worth of cold weather - which, down here at least, is exactly what we ended up with (with the exception of the overnight period of the 26th-27th, in which temperatures went above 6C for four hours).

are you kidding? Lol, Tallyho does, have never scrolled through his/ her posts. 

Tally doesn't count , he only does it to wind everyone up

wind up yes, lol. 😄 But I thought he was genuine.

This week I will mostly be watching the ensembles.

Hopefully the trend will continue and that by next Saturday we can start looking at some specifics. 

If that was to come off my goodness. Heavy snow definitely.

Most of the GEFS are good at long range. Clearly a strong background signal being picked up for a split vortex and atlantic ridging north