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GFS disrupts the trough at it approaches UK at around T+150 and ECM at around T+192. UKMO at a point presumably beyond T+144. Once this has happened the models seem to want to push the westerlies in. Because the trough disruption and following westerlies are predicted so far into the future there may be a few surprises between now and their actual onset and it may be prudent to closely watch the period up to T+72 for subtle changes that could have an impact further down the line.

Yes and it is also noticeable that GFS is showing a definite block with a closed high circulation over the north of the UK and a weakness apparent to the south while ECM shows a strong ridge extending back northwestwards to Greenland.

http://www.wetterzentrale.de/pics/Reurmetd.html This link shows the falling dewpoints now into Germany and parts of SE Europe which are likely to filter towards us erratically over the coming week. As has already been stated the current set up with a high to the east or southeast will inevitably lead to colder surface conditions atleast in the east and south. However it is rather early (only 10 days past October) to be looking for a cold spell. The models continue to indicate that the high will meander around to our east until the atlantic eventually takes charge again. The fascinating question is that when the atlantic does take over again will it remain dominate or will the ridge to the east keep reappearing through the winter. I think at the moment it is very difficult to even guess at what lies ahead and the waters are muddied further by the unknown effects of the such things as the current high sunspot activity (220 yesterday). Quite simply and rightly or wrongly I have always believed that in the winter when the sunspot numbers are high the pole fills up with low pressure and when sunspot numbers are low it fills up with high pressure.

Europe cooling down on its own is a very valid point especially with some of the output we are seeing at the moment. If the ridge to the east were to persist then cooling of the continent would occur by various mechanisms for example radiation under clear skies, radiation from the fog top when its foggy, radiation from the top of low cloud when that is present and advection of colder air from further east. Eventually much of Europe would be under a cold spell and with a high to our east or even southeast the colder air would inevitably filter into the UK. The key is whether the ridge to the east persists into winter.

Impressive high pressure just about covering the entire polar basin with an associated easterly component to the wind encircling the northern part of the globe. http://www.uni-koeln.de/math-nat-fak/geomet/meteo/winfos/arcisoTTPPWW.gif

18Z GFS upto T+114 shows the cold trough to NE closer to the UK.

ECM shows pressure rising to the east in the latter stages with the atlantic lows skirting the west of the UK. This has been happening repeatedly during the last month giving a week of milder weather until the lows are deflected to the NW. Then a week of cold follows. So the next 6 days look quite chilly and then perhaps a milder interlude until the altantic energy reduces once again and we look to the east or south east for the cold. However actual condition looks unusually blocked in higher latitudes with the polar high engaging the sub -40C air and dragging it westwards albeit a long way north. So although ECM looks plausible I would not be that surprised to see a different outcome along the lines that CC is suggesting.

Drier air has filtered north from central France overnight and dewpoints over northern France are now quite low. As the low to the northwest slips southwards the wind should gradually back and draw this low dewpoint air towards the south coast and turn the rain to sleet or snow.

Latest GFS has the low slighly further south - a bit of a trend ?. Main centre at T+90 in Biscay.

I have noticed the developing high to our north on the actual circumpolar analysis chart. It is not difficult to see the eventual outcome that you have been suggesting and given the oddity of this winter and the way the pattern seems to keep resetting itself and also the fact that late winter is a more favourable time for blocking it seems all the more likely. As it is not even mid month there is plenty of time for more cold spells before the months end.

It is starting to look like it might turn severe especially with the snow cover to our east mostly intact.

Latest UKMO T+72 fax shows the alantic lows slightly futher south than the previous run and the ridge extending down to Iceland is stronger.

Latest T+72 UKMO fax appears to be an upgrade and puts a bit more of the UK at risk for snow.

7 inches of level snow at 600 feet. 2 of the inches fell overnight. Patchy melting snow at lowest levels. 6 foot drifts in some higher exposed parts with an avalanche blocking half of the carriage way of the higher part of the coastal road during yesterday morning which was cleared by a buldozer during the afternoon.

It has been noticeable that in recent winters as a cold spell comes to an end the models tends to develop renewed cold spells that do not usually materialize. However this year unlike many recent winters there is a good snow cover over virtually all of northern europe and there has been sustained high pressure over northern Russia and northern Siberia with extensive intense cold. So the tendency of the models to bring back the cold from the east next week may well have more substance this year.

UKMO have just put out warning for snow on Tuesday.

Hail is still lying in patches after yesterday evening storms which deposited 2.5 cm of level hail here. Some of the hailstones were 7mm diameter. Three separate thunderstorms ocurred during the evening giving around 20mm equivalent rainfall.

The shortwave currently south of Greenland developing in the cold air needs watching. If it over develops and hangs around to the west there is a danger of it throwing up a ridge from the SW and putting us in mild SW flow. However if it fails to develop much and runs southeast we will be back in cold air much sooner.

I just mentioned to my wife that there could be blizzards later in the week and having known me for 30 years she just burst out laughing - so much for her faith in my predictions !.

If you have access to charts between 8 - 14 December 2007 have a look and see if it looks similar to the model projections for the same period 2009.

The problem is that the ECM looks plausible and not totally dissimilar from around this time in 2007 where as the GFS looks extreme.

My wife has just said she doesn't understand why we are getting excited as we normally get a couple of cold days at this time of year. I suppose she is right but it is facinating to see the synoptics of next ice age even if they are always just out of reach.

Some very low temperatures leaking out of the latest Russian high and creeping southwestwards. http://www.wzkarten.de/pics/Reurmett.gif

I understand that if the wavelength is of sufficient length retrogression of the longwave pattern will occur. Is 70 degrees longitude the length at which this can start to occur ?.

GFS appears to repeatedly initiate with pressure too high over Greenland - probably about 20 mb too high on the 18Z output. No wonder it is showing such extremes in FI.