http://modeles.meteociel.fr/modeles/navgem/runs/2014010806/navgem-0-144.png?08-11

The best model in the universe is producing some pretty tasty synoptics.

... or lake-effect rain, if the air off a currently less than figid Continent isn't cold enough.

http://modeles.meteociel.fr/modeles/gem/runs/2014010800/gemnh-0-168.png?00

http://www.meteociel.fr/ukmo/runs/2014010800/UN144-21.GIF?08-06

http://www.meteociel.fr/modeles/ecmwf/runs/2014010800/ECH1-144.GIF?08-12

http://modeles.meteociel.fr/modeles/gfs/runs/2014010806/gfsnh-0-186.png?6

With these Operationals on view today , maybe it has taken some by surprise, yes yes we know how much info the Met have but the above wasn't on the radar 2 or 3 days ago and now this, maybe they are waitintg for some continuity in runs before mentioning an Easterly ??

Just a thought

True.  But the cold pool of air is yet to reach our eastern friends,  when it does -16's are currently being forecast over the north sea.

exeter have never signalled this possible easterly. they talked of a pattern change later in jan (apparently due to glosea 5 output which appears to have now waned somewhat, judging by today's update). IF this easterly verifies, the only models that deserve any credit will be ecm ens, followed by the ecm op plus the gem op. tbh, the ecm ens picked up on the lowering euro heights from 2 weeks out but the build of scandi heights was led by the op.

the fact that they remain cautious is due to about 50% of the mogreps-15 and 40% of the ec members (re ian F on NW) not supporting the undercutting scenario. given the trend, will be a surprise if these dont fall into line tomorrow but a sinking block or a more mobile flow cannot yet be discounted. remember that the met office forecasters are first and foremost, scientists working with model data. they will go with the most likely outcome as indicated on their models, not what looks likely to be the case come tomorrow.

as far as longevity of any cold spell is concerned, the ecm extended have consistently indicated a return of a stronger jet aimed at the uk for a while now. however, it isnt really coming closer than day 12 and if anything, the jet is struggling to get through the meridian. i have a feeling that the trough dropping into the states back end of next week will dictate what happens here. if it doesnt dig far enough south, then i expect the jet to fire into the atlantic and probably take us into a period of cool zonality with low heights holding to our se. if the trough does dig into the middle states, then expect a scenario similar to what we have upcoming where a srong ridge is thrown into the n atlantic and our cold spell is sustained for longer.

Yes, but the initial easterly is not shown to be coming from Scandinavia and over the North Sea. I don't think the models show any minus 16 uppers off the coast of E Anglia.

http://www.meteociel.fr/ukmo/runs/2014010800/UN144-21.GIF?08-06

Look, I don't want to make a big thing of this - I have nothing to do with the Met Office. I'm just trying to construct a logical reason behind those forecasts issued at midday, other than "they haven't seen the model output which we've been drooling over for a couple of days."

That low needs to come south a couple of hundred miles and then we'll be talking. 

A warm North Sea is exactly what you want with a winter easterly, since it propagates that "lake effect" snow. Although the sea is warm, the fetch across it is not long enough to drastically modify the air - the only caveat is that the east coast itself would probably see rain, but 10 miles inland and beyond would get snow.

Westerly winds, even if they originate in a frigid America, have to cross an ocean, so are heavily modified by the time they reach us, hence it is invariably rain from that direction.

A salient point Marcus and broadly backig-up what Ben (Arcus) has also posted.

Hanging on every word of the UKMO extended text outlook is as foolish as taking every FI GFS run as gospel. Should the trend continue and exhibit some repetition then the outlook as posted in the UKMO text will alter to reflect this.

At the risk of repeating myself, ecm is a better model than gfs because it scores better on the method of verification agreed upon by forecasting organisations worldwide.  the general order at days 5/6 are ecm followed by ukmo and then gfs,gem,jma in a huddle. navgem follows on a bit further below. ecm tends to be around 86% at day 5 whilst gfs is around 83%.

in the real world, that may not make a huge difference, but it is a measured, proven difference.

Fair enough, MM. I do understand the lake effect, and how the short journey across the Channel isn't enough to warm up cold air off the Continent significantly. But I'm still doubtful whether the air off the Continent would be that cold in the first place.

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

Yes, eventually it cools down, but until then it's a lot warmer than average for the time of year.

A cold blast of air moving across the continent on days 2-3 will shove aside the current relatively mild air across Scandinavia with ease.

By the time we get any easterly, deep cold air will have sat over Scandinavia for 3-5 days based on today's model output so far, with dayime surface temperature maximums generally ranging from -7 to -12 Celsius away from the mountains (where it will be below -20 Celsius for the most part). Parts of Germany will already be having sub-zero maximums as well.

...so I reckon it would be plenty cold enough to achieve lake effect snow, especially with the very low cointinental dewpoints involved.

A bigger deal IMO is that the sliding trough does have to play ball to keep the Atlantic air, with it's higher temps and DPs, down to our S and SW - and the ensemble data shows plenty of options where not only does the first trough not behave favourably (like on the 06z op run) but the second one doesn't either.

A cautious approach needed, then. Today I noticed that, after talking about the local flooding from the Thames, the local radio went on to mention that things will get worse if there's a spell of freezing weather, as it would do further damage to flooded properties. I wonder if they added that in light of this morning's runs, just in case...

A tweet from big Joe in America - ECM showing day 10-15 temp anomalies in Europe, widely 4C below average in England and much of Central Northern and North Western Europe. Clearly shows LP to the South and HP somewhere to the N.

https://pbs.twimg.com/media/Bddci18CYAAA4n0.jpg:large

Thats not ECM, thats GFS. These sort of charts are made freely avalible by NCEP. 

Oops so it is.

Those maps are actually fairly easy to make in Grads (even for a complete begginer like myself). Anyone that has ECMWF data, however, looks extremely impressive. The only publically avalible stuff is the basics we all use; but ECMWF has so much more than that. 

New thread coming in time for the GFS 12z- closing this one shortly.