Model output discussion - 1st December onwards

[Ice Day]

Not sure it's quite going to make it on this run, but a definite shift west vs 00z.  Look at the cold into central europe at 150hrs

[johnholmes]

Taking a look at how the anomaly charts have been trending over the last 3 days or so.

ECMWF-GFS continues to be rather different from the NOAA outputs. They both have very slowly trended to where they are this morning, see link below. That is for the idea of the major trough edging east and extending into Europe. This has the effect of moving the ridge, which has been the focus of attention for several days, further north east. Contour heights have also been lowered over the 3 days to about 546DM in the far south of the UK on the products this morning. They are almost always 6DM or more lower than NOAA even when all 3 are pretty similar in their upper air pattern. Something they are not at the moment. Both EC and GFS are fairly similar further west into and across the North American continent. Indeed they appear pretty similar across the whole chart.

The last evening NOAA output for 6-10 days (the equivalent of EC-GFS) did not show anything to copy what EC-GFS have trended to wards. The 8-14 did just about suggest some indication towards the idea, perhaps (?) of the trough beginning to look as if it might extend into Europe.

Over the years I have generally sided with the NOAA output but several times in the past 12 months or so the EC-GFS outputs have led NOAA into a change in pattern. Will it be another one-too early to say but interesting even so I think?

Links below

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

[northwestsnow]

Split god damn it!!!!

Thats one strong scandy high at 156h- 1045mb.

Some very frigid cold air sweeping into Europa

[Mark Neal.]

That low to the SW, seems to move in from no-where. Moving slowly NE?

[radiohead]

I don't like to see stalled lows like that. More flooding is not what we need.

[booferking]

Looks like a better run this is going to be so hard to model even up to 4 days out.

[Mark Neal.]

Starts to fill? then there is 2 more in the Atlantic, need them to head SE if we stand any chance of undercut.

[bluearmy]

JH, I presume the EC-gfs output is more pronounced re high/low heights because it is taken from op data as opposed to the NOAA chart which is generally ex ens and always cross model smoothed out.

 

[johnholmes]

You could be correct ba but it is interesting in the, getting on for 10 years now, I have used these anomaly charts it is only in the last 12 months that I have reservations in always taking NOAA over them in terms of what is being shown.

 

[booferking]

Nice battle here will be nice to be on the cold side of the battle some big snow totals.

Jet well under i might add.

Edited December 26, 2015 by booferking

[Geordiesnow]

One indication which may suggest a westward movement will be how far towards the UK those deep lows get, the further West they are, the indications would be the block is having more of an influence therefore the blocking will be further West. 

I'm not bothered if the models are showing an easterly yet, all an easterly showing at 180 odd hours will do is raise the hype and people will expect it to stick from run to run where in reality, that will never be the case. I think its more likely there will be some sort of block with some very cold air coming down the eastern side of the high but just how far westwards will that cold get and that sort of detail will continue to vary from run to run. I stand by the fact no run is a bad run as long as they don't sink any block(like yesterday's GFS12Z run did to an extent) so for me this mornings ECM run is a decent run because it does not do this even if it doesnt show what we want too see. 

This afternoon runs will be interesting but certainly not critical because many more runs will be needed. I still say the easterly is an outside bet at this stage but can't be discounted. 

[bluearmy]

19 minutes ago, johnholmes said:

You could be correct ba but it is interesting in the, getting on for 10 years now, I have used these anomaly charts it is only in the last 12 months that I have reservations in always taking NOAA over them in terms of what is being shown.

 

That's an interesting anecdote john - wonder if the ops are becoming more reliable in the 6/10 day timeframe.? Not sure the stats back that up though. 

The 06z op takes an interesting turn in fi. Now that's a hemispheric pattern that would bring winter proper.

[knocker]

The gfs now has just one depression at NY which is a tad further east which is just as well there are gusts in excess of 90kts in the eastern quadrant just west of the Hebrides.

 

[shaky]

Crazy 06z run and the best thing is it looks identical at 144 hours to the ukmo!!!you would think this evenings ukmo at 144 hours would have trough disruption into europe considering how it looks at 144 hours on the 00z run!!

[knocker]

The Georgia express and the LP passengers

[northwestsnow]

3 minutes ago, shaky said:

Crazy 06z run and the best thing is it looks identical at 144 hours to the ukmo!!!you would think this evenings ukmo at 144 hours would have trough disruption into europe considering how it looks at 144 hours on the 00z run!!

fingers crossed shaky, gfs 6z ens awaited with interest

[shaky]

Good gosh the control looks more favourable for the undercut than the op!!!this evening could either be utter despair in this thread or its gona go into meltdown!!

[fergieweather]

14 minutes ago, bluearmy said:

The 06z op takes an interesting turn in fi. Now that's a hemispheric pattern that would bring winter proper.

Quite so. Presently, the E/SE'ly cold solutions courtesy of the diffluent block out east - as offered by some recent deterministic output across various suites - is rated as 10% PROB. Whilst a mobile/zonal pattern remains the stronger and thus more favoured signal out beyond d10-15, clearly any mean fields will be skewed by these energetic ENS members (& with inevitable tendency to lean back towards climatology) versus those stamps (presently a minority) showing the opposite. I know we hammer on about this, but inspection of individual stamps is critical, rather than pronouncements based solely on ENS mean.  As it stands, indication of an eventual change to the pattern has bolstered slightly, rather than diminished. But it's clearly all highly tentative for now.

[northwestsnow]

2 minutes ago, fergieweather said:

Quite so. Presently, the E/SE'ly cold solutions courtesy of the diffluent block out east - as offered by some recent deterministic output across various suites - is rated as 10% PROB. Whilst a mobile/zonal pattern remains the stronger and thus more favoured signal out beyond d10-15, clearly any mean fields will be skewed by these energetic ENS members (& with inevitable tendency to lean back towards climatology) versus those stamps (presently a minority) showing the opposite. I know we hammer on about this, but inspection of individual stamps is critical, rather than pronouncements based solely on ENS mean.  As it stands, indication of an eventual change to the pattern has bolstered slightly, rather than diminished. But it's clearly all highly tentative for now.

As you are no doubt aware Ian the situation round Lancs/west yorks is critical.

We desperately need a break from this relentless onslaught one hopes some kind of anticyclone can put the brakes on this evil Atlantic sooner rather than later

[Jason M]

GEFS are interesting. Lots of runs get close, but not many cigars on show 

i worry for the NW with what's being hinted at as there is potential for a lot of rain as the uk looks like being the battleground.

[nick sussex]

Still no resolution this morning so more drama to come. Its always the same story with this east v west battle.

I'm not sure we're looking at the convective type easterly scenario for a while, the interest is really whether trough disruption occurs near the UK.

This scenario either ends up as wet and cool or very cold and snowy.

A positive from all the outputs even with near misses is that a lobe of high pressure hangs on to the ne.

The outputs vary in interest, although the ECM is less enthused it could still go either way especially when you look at the ECM spreads.

Upstream still waiting for the updated MJO, the smoothed out version still looks interesting:

 

 

 

[knocker]

41 minutes ago, bluearmy said:

That's an interesting anecdote john - wonder if the ops are becoming more reliable in the 6/10 day timeframe.? Not sure the stats back that up though. 

The 06z op takes an interesting turn in fi. Now that's a hemispheric pattern that would bring winter proper.

Just to make sure I'm with what you are saying blue are you talking this

 

[chrisbell-nottheweatherman]

2 hours ago, Jason M said:

What hype? You must have been reading a different thread 'mate'.

I think people have been very realistic and measured tbh. Its been pretty much a ramp free zone in here.

Always been odds against, but some runs have shown an easterly and therefore peeps are entitled to comment.

Anyway, let's see what the day brings.

 

Sorry, but that's rubbish.  There have been plenty of people getting massively over-excited by something that was never going to happen.

[Geordiesnow]

7 minutes ago, chrisbell-nottheweatherman said:

Sorry, but that's rubbish.  There have been plenty of people getting massively over-excited by something that was never going to happen.

I think some sort of excitment is understandable but as long as people realise the details of each run will vary then I don't see much issues of people getting carried away. 

I also don't understand why you saying "something that was never going to happen" - we don't even know whether it will or not! I think its an outside bet at this stage but aslong as you got the blocking there, even if it does not happen straight away, you can't rule out the potential for cold. 

[IDO]

1 minute ago, Jason M said:

GEFS are interesting. Lots of runs get close, but not many cigars on show 

i worry for the NW with what's being hinted at as there is potential for a lot of rain as the uk looks like being the battleground.

Yes no sign of the GEFS moving towards an Easterly, like the 0z run a very small cluster of only 3 by D9, so we need that to start moving in the right direction. Again the op has 2 other members with support but the op is far and away the best out of that small cluster for cold. The control is a train of lows and fronts crossing the UK from D9, a strong zonal run. The ENS temp shows the op as an outlier and a colder run from early on: 

Looking at the GEM ENS, there are 4/5 Easterly's by D10, so again a small cluster. With IF suggesting 10% for the ECM then this remains a low chance, probably what you would expect when a wave amplifies the pattern (normal errors). The latest CFS w2 suggests the HP cell being pushed east and an Atlantic flow re-establishing and w3 and w4 offers more of the Euro high/Atlantic trade off:

   

The most likely solution is the HP cell being slowly pushed East as the lower heights moving in overwhelm the block. Still a few days to resolve this so could go the other way.