swilliam

Looks like the ECM would go on to develop some very active lows from Newfoundland based on the temperature contrast showing there.

None I think, this is the 850s for the middle of Sweden (taken as being the average) mostly around -5C except for a couple of days. Given the existing snowcover and virtually no worthwhile daylight - not much of a thaw I would think.

It's late!

Interesting GEFS Control in F1 in terms of developing scandi high and look at the cold pool. Illustrates how we can get to this to this point as well - not sure why people saying they cannot see how it can happen when I thought SM had explained how quite eloquently. V. low chance of course but we are looking for signs.

If mild was the default pattern it would not be mild. Average is the default pattern (whatever that is).

Try looking at 2, 3, 4 11, 12, and 17 which are all quite similar. and others develop the link at a later date.

Well it gets there in the end with a Russian super block - lots of variations on offer I suspect at this range. Plenty going on the other side too.

Interesting mean from the GEFS at 348. Even at this range there are significant ridges or blocking areas in the aleutian and sceuro areas . Looking forward to see how it all pans out something interesting is afoot ones suspects.

Just to add to this these are the maxes from the 06Z in FI under the influence of the Scandi block Pretty cold in Europe too

The models show over the next few days (until the Northerly in one form or another and with variations on longevity) is that it will be dominated by a cloudy high with slightly below av temps by day and pockets of frost by night.. Variations between models - none so nothng much to discuss - no interesting weather and not much variation. Even our local weather BBC forcaster talked about being colder next weekend (with the caveat that it will be 7 days away)).

Not sure where you guys are getting this flatter pattern from. Obviously if you have a Northerly toppler it will be followed by a few days of a flatter profile with energy going over the top - otherwise it would not be a toppler. This is shown on the jet profiles for 192 and 300. Thereafter there is tendency for the jet to become more amplified at a lower latitude and aligned nw/se. This is shown in the the jet profile of the OP GFS and it is clearly going to lead to a major cold outbreak as shown by the pressure profile. This is also well supported by the ensembles with the ensemble mean at this time shows virtually no jet.This is because many solutions are going for the low latitude/high amplification/nwse alignment scenarios. There are very few that are flat or zonal Just for example this is no 1 but there are many more like this (I am sure Frosty will post these up). So for my money we will have a few days of dreary anticyclonic weather possibly followed by a Northerly toppler. Thereafter we will see the high move further west as the PV transfers more and more to the Russian side. This will allow ever more potent cold outbreaks alternating with wet and windy milder interludes as each depression tracks ese and pulls the colder air down. Whether we will ever get to a solution shown such as GEFS 1 (and others) remains to be seen but I do not see this flat profile that you and IB keep telling us will remain with very little potential for cold. So I think it is a bit misleading to say everything will be flatter after the toppler (should it occur) - even from the 12z op.

It is sweltering in Northampton 27C with DP of 19C. after a sunnyperiod following the luchtime storm clouds beginning to build now. Looks like clouds building to the S as well - both in the channel and in Biscay So plenty of opprtunities. Looks cells heading twoards NW England already as per the Meto Warning Could be veyr interesting the next few hours for some.

I think mild (and rather mild) is normaly used in late autumn, winter and early spring and means about 2-3C above average. In spring and summer they (MeTO) they use warm (and rather warm) as presumably they think Joe public would get confused if they described 10C as warm..I am not sure when they officially switch - maybe JH or IF can clarify. Whatever the actualities are it is clear that there is not going to be anything significantly above average for the next couple of weeks. Back on topic it seems that the GFS 12Z has continued the idea from the -06Z of the next depression not undercutting at 120. This leads to the high orienting itself on a SE/NW axis and therefore we end up with a less cold SE flow. In contrast the UKMO does undercut the depression And we end up back in a cold NE flow 0Z ECM went with the UKMO - are we heading for another stand off I wonder

erm no - these terms (mild, cold warm etc.) refer to the difference from the average not to actual values - hence why the current Meto foracst for the next few days refers to very cold even though temps are around 5C which would certainly not be very cold in January - it would be rather ciold..

Thats average not mild (nice in the sun though if we manage to get any.

But if you look at why these do not deliver (the very low 850s) in your area you will see that it is because the low in NW Biscay has more energy, stops the front clearing as quickly and this then pushes N later. This is actually being shown on some of the ops - hence the snow warnings in the S - the actual position of this front is very hard to predict this far out. This actually leads to much more snow but not such itense cold -some may say that is better. The point though is that the actual difference beteen the e ensembles is quite small but has large effect on the 850s in your particular location. So the overall pattern is pretty similar and well predicted but with small local differences. This will not show up in the verifcation stats. I like the way you say it is acceptable for the op to get it wrong - really they are just models.

Selective memory again - the prediction was for the end of last week, this weekend and beginning of this week. It related to the cold weather we previously had being pushed away. This did indeed happen as predicted we had a few days of a cyclonic Westerly followed by the anticyclonic SW we have just enjoyed by the weekend. So IMO they got it about right. I don't why people continually want to pick on the MetO as I think in general they do a pretty good job - it is wearisome for me to read so must be worse for IF. They are not right all the time of course but who is. I am also not sure why people are obsessed with what they are predicting as well. It is clear that in the medium range there are nearly always several options on the table and as they are always held to account (see above) they will always predict the most likely outcome based on the information before them (which is more than we have). On here we can freely discuss the other options (as we are doing) as they are usually mor interesting. Personally I think we will see an upgrade for the snow potential Fri/Sat as that is what frequently happens in these situations. It has been equally wearisome reading continuously that it is going to be dry in the upcoming cold spell. We all know that precipation changes at the last minute - for better or worse.

Yes this evolution with more of an undercut is much better - both short term and long term. In the later frames you can see the movemnt of the PV and cold air to the North is much more favourably aligned as the HP moves W. This is much more likley to deliver something from the NE compared to the ECM at t240 that some people seemed to be getting excited about. As NS says with the (likely) jet profile and the alignment NW-SE of the HP even f the high extends more NW the cold air is only going SE into E europe. It was suggested the low in the Atlantic would undercut but it seems unlikely that even if it did that it would go right underneath which is needed to bring the cold air in from the NE

Yes a large number of options for the position and orietation of the high. What is noticable though is that at this stage most of them do not have the high very far N (mid Norway seems to be about the limit). Also the majority are aligned NW-SE meaning E-SE flow at best (on average remember). This means the most likely chance for significant snow is from fronts approaching from the SW. Having not had this for several winters it seems to be a recurring event this season.

GEFS definetely now on board with an easterly if somewhat delayed compared to the Euros Mean t192 and at t240 with the cold fast approaching

Well I think the ECM ensembles are showing the same - they do not seem to have been posted tonight, probably because they show that after the slider a return to less cold conditions seems to be favoured..

You told us several times yesterday to expect a backdown (no reason given) and it didn't (12z or 0Z) - why do you think it should this time?

ECM Ensembles out As expected quite a bit of divergence after next weekend although the majority stay cold. This is evidence by the ensemble means <-8 for many eastern and central areas at 168 Still below -6 at 192

Still snowing here in Northampton but with the moon shining through the clouds - more than 12 hours. We have 14 cm - about 8 today - very pleased.

Bit misleading this - he is only refering to his forecast area of the West Country.This is exactly what is shown on the T96 fax - west wind into S Areas with rain.Snow N of the occlusion and E wind. This will not affect the mid term as just a local effect Not sure what to make of the 120 Without seeing uppers, dewpoints etc not sure where the snowline will be.