ECM mean at day 10

http://www.wetterzentrale.de/maps/ECMAVGEU12_240_2.png

Weak, if chilly feeling westerly sourced flow. I can't wait..

Excellent agreement too  http://www.meteociel.fr/modeles/ecmwf/runs/2019010812/EEM1-240.GIF 

Anyway CP remember we can discount day 9 so day 10 not even worth a look.

How did you do that ? 

I'm trust my gut and my gut tells me that the worst case scenario will most likely verify, even if it shown to be 10 or 20 days away. There is just no getting away from the influence of that parasitic high this winter. You, being placed furthest away from it, will no doubt see something of interest, and I hope you do. But for me, this winter has become is a total write off in terms of anything of interest. So much for all these predictions of greater storm intensity and frequency during the winter months I have been reading about over the last decade, because the complete opposite is happening. Every year it just gets worse. 

I don’t blame you to be honest but I’m happy to watch the trends and see what happens. Maybe it will come to nothing as has happened in the past, but it’s not always the case even in our temperate maritime climate. The signs are pointing steadily in one direction but in these isles it is never a straightforward journey.

However I would be surprised if the GFS op run did not continue the trend to more unsettled midmonth with at very least some cold shots from the N/NW following at various intervals.

Followed shortly thereafter by a northerly plunge and cold locked in from the northeast, a la GFS, I would imagine.

I can confirm the GFSP12z data is still not available. There hasn't been a notification to explain what has happened, however as it is not  designed for production applications there is no service level provided or obligation for NCEP to run that model. The GFSP18z run also appears not to have initialised yet.  Personally I would be very surprised if the GFS upgrade goes in this month: 1) The govt shutdown may well have impact  2) The http to https transition isn't complete yet and there have been some issues with it.

Encouraging trends today all round from an anomoly perspective. (ECM, CSV2)

Let's see where we stand in 5 or 6 days.

By that stage we should have a better idea of where the blocking high will sit.

Extreme caution required due to timescales.

 When you way up all the evidence SSW, MJO tropical forcing etc, etc  this is not a run of the mill gfs fantasy island wind up. Winter is coming and in another few days as the runs become better and better and the way forward even clearer some posts on here tonight are going to look very silly indeed.

Now where did I put that snow shovel.

That said there is a definitive cooling trend, but wether that be from the north west, north or east is another story. It may turn out to be good for northern hills, but beyond that is anyone’s guess.

Careful 

In support of my post just now, I was just looking at the 240hrs ECM spread chart on the other forum. Cannot reproduce it but it shows the highest spread in the Northern Hemisphere in precisely the same area I have mentioned.

Just a glancing blow at the transition stage but interesting given the tweaking at that timescale

What I find interesting is that usually FI cold charts follow one of two patterns, a straight northerly or a stonking easterly, both of which look pretty on the screen but if they arrive are often not that interesting on the ground. 

The GFS this week, by contrast, has been serving up some very messy cold charts, which while they might not have very deep cold uppers, look more like the charts of yore with lows bumping into cold air and stalling, which could give mega dumpings of snow. 

we need luck on how the vortex is split, too much energy on one side could mean close no cigar - even break over UK would provide the coldest scenario. Some very cold ENS will show but a few with chilly weather and cold rai. Which way will it go...

18z ensembles for London:

ECM 12z ensemble for London

In terms of 2m temperature the op was at the bottom of the ensemble spread but not without support.  

Beyond day 10 there is a minority giving an average to slightly mild outcome but the majority go cold or very cold. A few ice days appear at the end.

18z FI control run in FI: - Looking very blocked (-10c @850hpa)

18z Op run - not a good run but ends cold & and becoming more blocked:

Why isn't the 18z Parallel run up and running or updating and still showing Monday's chart?

Anyway it ends more blocked as well!

http://old.wetterzentrale.de/pics/MT8_London_ens.png 

...but not spectacularly so.

Week 2 - probable ice days over the mountains in N Britain, and lots of very cold air over Scandinavia. Just need a light NE flow!

http://www.wxmaps.org/pix/temp4

EDIT: but much less impressive by mid-morning!

Clear signal on the GEFS for colder conditions later this month. A couple of caveats:

1) There are a number of big dippers on the plot but very few runs are staying in the trench for long. That suggests the probability of cold and mild air blocks being close to the UK without one firmly having the upper hand. Without looking at the details, it would typically mean that snow is more likely in the north.

2) The 30 year 850hPa mean ticks up during the middle of June. Someone posted a WZ link and it appears consistent with the TWO plots, so I don't think it is an artefact. The effect is to make the dip in 850s look a little more pronounced than it is.   

Despite 1 & 2 the outlook in my view is interesting but I would urge a lot of caution at this stage.

https://www.theweatheroutlook.com/twoforecasts/ensemble-forecast.aspx?location=London

The Op was an outlier later in FI; still a lot of very cold runs amongst the ensemble set.

http://www.meteociel.fr/modeles/gefs_table.php?ext=1&x=&lat=51.5085&lon=-0.12574&ville=Londres