Model Output Discussion

[SP1986]

I do think there is a certain air of assumption that this cold spell is written in and I think this is a dangerous game to play (not literally dangerous of course) because I believe that no scenario is written in yet. I've seen more grounded predictions crumble, and I just think there is not enough agreement in the models, and not enough time of agreement to warrant any certainty in a cold pattern at the moment.

[Snowyowl9]

GEM goes with a potent easterly more so to earlier.

http://www.wzkarten.de/pics/Rgem1201.gif

And as Nick said JMA looks great too.

http://www.wzkarten.de/pics/Rjma1441.gif

As you can see I`m more interested in the easterly

[Geordiesnow]

Its funny because if the current charts come off, yesterdays GFS runs would of been closer to the mark than both of yesterdays ECM runs. However typically as soon as the ECM trends towards the easterly again, GFS starts to trend towards yesterdays ECM model runs. Looking at alot of runs, i have to say the easterly is more likely but as most of the outputs have shown, there won't be alot of convective potential.

Hopefully the 18Z can come in line again and we can hopefully see a few short term upgrades in snow potential.

[yamkin]

Signs of a slight upgrade to the easterly early next week from this evening's 12Z runs bringing an increased risk of wintry showers for the southeast of Britain in particular.

UKMO and ECM are very similar at T+96:

http://www.wzkarten.de/pics/Rukm961.html

http://www.wzkarten.de/pics/Recm961.html

And there's some pretty chilly 850hPa temperatures associated with that flow:

The GFS 12z isn't as keen, but a quick look at the ensembles shows the operational was rather on its own in bringing a quick end to the cold air coming in from the east:

http://www.wzkarten.de/pics/MT8_London_ens.png

Its worth monitoring this time frame as the easterly may well be upgraded slightly over the next few runs - there are a number of ensemble members that look more like the 12z UKMO and ECM, i.e.:

http://91.121.94.83/modeles/gens/run/gens-18-1-96.png?12

It's quite astonishing to see the differences amongst the GFS ensemble suit at just T+96!

The T+96 and T+120 UKMO FAX charts later this evening will strongly support their own model I suspect.

Hi Paul,

A great post As other models like NOGAPS, GEM, JMA & GME are showing a colder outlook as well, what are your thoughts on these along side the UKMO, GFS & ECM models.

[Duane S.]

Take a look at the JMA tonight that shows the perfect example of how to keep the cold going from easterly to northerly, its a textbook example, its a cannon fodder model but as an example of what you want to see it's great.

WOW! That really has come straight out of a textbook! Shame it's the JMA though...

[Matty M]

I will be interested to see the 18z, a jump is likely.

I just got a feeling this easterly will be pumped up more and more.

But i will probably be wrong.

[bluearmy]

please dont 'diss' JMA. it doesnt do too badly in my anecdotal recollection. there are no stats either way. we'll see

[damianslaw]

After yesterdays ECM's rather bullish projection of the atlantic blasting across the country next week, what do we see today a fairly major reversal in support of an easterly and then northerly. Something fundamental has happened here with the ECM, it has picked up the upstream signals for displacement of the PV out of Greenland and into Scandanavia aided by amplification of the jet resulting in a northerly and the high to the east sinking south.

This is the scenario I believe will play out as we head through next week, the key question is whether amplification of the jet is strong enough to produce significant WAA up the western side of Greenland helping to strengthen any northerly, or whether we see a brief northerly incursion followed by high pressure settling over the country with every potential thereon for it to move east again..

However, you look at things, the atlantic is not in the mood to fire into a high gear it seems. Its worth noting how by February it generally weakens considerably even in mild El Nino years, with a projected weakening of El Nino, don't hold your breathe it is going to fire into gear any time soon.

A cold outlook potentially very cold as we head towards February.

[igloo]

maybe wishfull thinking but lets hope this evenings 18z run goes the same way as JMA

[Snowyowl9]

GEM keeps the easterly going strong at T144 and this looks like it could evolve into what JMA is showing.

http://91.121.94.83/modeles/gem/run/gem-0-144.png

[Ben_Cambs]

It would be great if GFS 18z could follow JMA,GEM and ECM tonight

[lukemc]

Hi,

A few questions with regards to the current output:

1) Even if the output indicates cold and dry with frosts by night would it still be possible to get widespread frontal snow events in the not too distant future like those that occurred in February 1996, 2007, March 2006 etc.? Of course we know that these situations can crop up at short notice and can be trigged by an incoming Atlantic front where the cold air fights back.

2) As we all should know, for the UK and also for most of Europe this winter has been, throughout so far very different synoptically and metrologically very different from the so called "even larger teapot" pattern that we have become so used too over the past two decades or so. During a typical modern type winter like 1997/1998 we usually had a very strong roaring Atlantic jetstream bringing mild weather (zonal dross) well into Eastern Europe and even as far as western Russia! Now everything is very different for example their seems to be a very deep pool of cold air within a few hundred miles of the UK which is a very short distance on a global scale. Have you seen the progged temps for Berlin for example they are expected to stay below freezing for a week or more with daytime temps well below freezing! Yes I know that Berlin is on average colder in winter than the UK due to continental influence but really only slightly (especially compared to places like Canada and the American Midwest) so that is very cold for them! So I am just wondering why some people where calling a mild (or average/benign) outlook for the end of January/into Febuary based on some model runs that have appeared over the last few days as IMO it would not take very much for that cold pool to reach us at short notice, anyway isn't that what happened earlier this month and in December, with parts of Eastern/Central Europe getting very cold first and then later it ended up effecting us?

Luke

[Frosty.]

It would be great if GFS 18z could follow JMA,GEM and ECM tonight

and ukmo

All things considered, much better output than 24 hours ago, the smoke has cleared somewhat and a fairly good chance now for an easterly feed during the first half of next week followed by a northerly blast, a reversal of how the first cold spell began back in december.

[PB22]

Hi Paul,

A great post As other models like NOGAPS, GEM, JMA & GME are showing a colder outlook as well, what are your thoughts on these along side the UKMO, GFS & ECM models.

Thanks Yamkin. I know that the likes of NOGAPS, JMA and GME are generally acknowledged as being the "lesser models", but I am actually pleased with what they are showing. I can recall a number of times from when I did the model summaries when the "big three" (GFS, ECM and UKMO) showed a cold set-up but the lesser models didn't, and the lesser models were actually nearer the mark! Certainly the output tonight is a lot more encouraging for a colder flow coming in from the east than last night IMO.

Edited January 21, 2010 by Paul B

[nick sussex]

The latest ECM ensembles are in for the Netherlands. In terms of easterly patterns these can be very helpful but tonight we're going to have to take into account the trend of the models to sink the block and push the trough into Scandi.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

So bearing this in mind i think we can see here that the ECM might be holding that nose of high pressure for too long around the 168hrs timeframe as the operational run is one of the coldest options, any onshore flow here normally lifts temps so i think the trend might be to see pressure fall quicker than the ECM implies to the east. There is very little support in the ensemble members to suggest a west to east milder flow but more a nw to northerly flow this is apparent with the main grouping later around the 0 to 5 c mark. Looking at the other output aswell as the ECM I think the way to go is the easterly looks okay with good support till around Wednesday then the trend around this time is to sink the block with high cell retrogressing into the Atlantic, the main point of uncertainty now is the amplification upstream which will determine whether its a nw or northerly flow and also whether the air is Arctic or PM.

[Matty M]

18z GFS certainly not budging much for the early easterly.

[Frosty.]

Next day JMA and so on

I think the JMA is a great model when it shows a bitter N'ly...bring it on I say. I just hope the trend continue for an E'ly then a N'ly as it will benefit the whole of britain from either 1 flow or the other at some stage next week. All we need now is another 18z like last night to complete a good day.

[La Bise]

Always a pleasure to see an emasculated Atlantic, long may it remains utterly impotent on the western side...

[PB22]

GFS 18z edges a little closer to the Euro's for the brief easterly early next week, but still isn't totally on board:

http://www.wzkarten3.de/pics/Rtavn961.html

http://www.wzkarten3.de/pics/Rtavn962.html

[January Snowstorm]

When all else fails let's drag the jma out

I fully expect the 18z to continue the clear trend of high pressure in situ

[bluearmy]

slightly better jet profile off eastern canada at T96. may dig a bigger western atlantic trough and take more energy south. small differences can lead to much bigger ones.

[snowmadchrisuk]

Is there not a point in the fact that if a cold spell doesn't deliver snow it might aswell be warm so we can save on oil bills, elderly can get out their house etc.

I'm all for cold if it leads to snow, high pressure over us is the great 'time burner' that it so often has proved in the past.If i got a pound for every time we had high pressure over us that i was told would lead to a bitter spell and didn't i'd be a rich man

This high looks like burning up the rest of Jan imo

The Weather will do what ever it wants ,and it isn't going to listen to your complains on saving oil . The ECM is very cold next week for England as is the UKMO.

[keithlucky]

The met is in full agreement with the ecm expect a upgrade to widespread sleet snow showers on north sea coasts becoming persistant at times sunday night.

Edited January 21, 2010 by keithlucky

[PB22]

Tonight's UKMO T+96 FAX chart:

http://www.meteociel.fr/ukmo/fax/fax96s.gif

Chilly with wintry showers for the southeast and goes with their own model.

The T+120 FAX chart: http://www.meteociel.fr/ukmo/fax/fax120s.gif

Also nice for the southeast cold and snow hunters.

[Snowstorm1]

Tonight's UKMO T+96 FAX chart:

http://www.meteociel.../fax/fax96s.gif

Chilly with wintry showers for the southeast and goes with their own model.

The T+120 FAX chart: http://www.meteociel...fax/fax120s.gif

Also nice for the southeast cold and snow hunters.

That would explain why bbc 5 day forcast has light snow for me on tuesday. Also the on the latest 18z its brining in the northerly in earlier http://www.wetterzentrale.de/pics/Rtavn1381.png