Model Output Discussion:

[TEITS]

I think the gfs hasn't picked a signal for increased Atlantic energy and continues to show cold outputs.

I am expecting this signal to be picked by all models by the end of today!

Karyo

Normally it would be the operational to pick up this signal rather than the ensembles due to the higher resolution. However the reverse is true with the ECM. I still can't believe some call a mean of 2C as nothing special for London.

Personally im just going to wait and see before making any assumptions.

[Mark Bayley]

Have you even looked at the 06Z??

http://www.wetterzen...s/Rtavn1441.png

Sorry but it does annoy me when members make inaccurate comments.

Personally its very simple for me. If the UKMO trends the same with agreement from the ECM then its game over. However if the reverse is true then its game on. Also if the 12Z GFS trends exactly the same as the 06Z then I feel this increases the chances of the UKMO backing away.

Just seen your comment about the ECM ensembles. Are you joking with that comment. What do you expect a mean of -10C in London.

Aren't you the same person who moaned that the last cold spell would be dry and accused members of being misleading.

Those London Ensembles do look pretty good! Not exactly mild, with the mean trending colder

The GFS ensembles on there own are not to bad with many still trending colder, in the long term.

I agree about the UKMO carrying on with its trend with the ECM following. Hopefully the GFS 12z keeps the Easterly with the UKMO backing down from the Atlantic returning. I can't say I'm that confident however just about anythings possible, as we have seen so far this winter!

Edited January 30, 2010 by mark bayley

[Blizzard_of_Oz]

Sorry that was a spelling mistake it meant to be RELIEF not belief sorry about that.

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Posted Today, 09:04

Blizzard_of_Oz, on 30 January 2010 - 08:39 , said:

This may not be the right thread but look at this from Ian Fergusson's Blog.

Remember February 2009? The deep snow that brought London and much of the southeast to a spectacular standstill? It's by no means impossible that we'll see similar weather establishing across the same parts of the UK in a week or so.... and possibly more widely, too.

Usually, I restrict my blog to matters of forecast interest within a few days of the here-and-now, but the growing signs - and growing forecast model consensus - signalling a return to much colder conditions by the end of next week deserves an early mention. More on all this in a moment...

So onto next weeks developments..

The week actually starts with a temporary return to something a tad milder. B y Tuesday, we expect a spell of fairly widespread rain - with hill snow on it's leading edge, tracking eastwards - behind which, temperatures will peak somewhere around the seasonal average. But thereafter, the trend is one for cold anticylonic weather to steadily exert itself across the country and into the second part of the week, a return to something a good deal colder will become apparent pretty much everywhere, with the exception of the far West and NW.

Between Friday and Sunday, developments are expected to yield a bitterly cold easterly flow off the continent, bringing the risk of snowfall - some potentially heavy - into parts of the SE initially, with a chance of this spreading further westwards to affect other areas. And beyond that, the anticyclonic south-easterly flow could well be replaced by a cyclonic east-to-northeasterly version, thereby continuing to offer a growing risk of further snow.

Hes not the only 1 either thats saying the same thing, Im sorry admin if this is the wrong thread but we need that sort of belief in this thread now.

Belief? What does that have to do with it? This isn't a religion you know, we can't influence the weather any more than we can influence those imaginary gods that some people think exist.

I'm thinking that Ian Fergusson is wrong, also that many people are clutching at too few straws, the real cold weather is always a week away (ie in FI) on the model output, etc. Sorry, but I don't think it's going to happen. I'd LIKE it to happen, but I think it's more likely that I'll suddenly develop the brainpower of Einstein overnight.

I'm a realist, I don't operate on flights of fancy and what 'should' happen or what I (or others) want to happen. With the weather, what will be will be.

Enough said.

[Duane S.]

I am not pleased with this morning's output! A definate shift towards the UKMO scenario by the ECM operational and the GFS ensembles: http://www.netweather.tv/index.cgi?action=ensviewer;sess=

I think the gfs hasn't picked a signal for increased Atlantic energy and continues to show cold outputs.

I am expecting this signal to be picked by all models by the end of today!

Karyo

I know what you mean but is it a case of the GFS not picking it up or some of the others picking up what won't be there?

We always knew this was going to be a very fraught period as the models try and get a grip on things and I don't think it will be even close to being sorted until around early Monday. By then we will know (very roughly) where we our heading. Or at least you would have to hope so!

[nick sussex]

There are only so many bites of a cherry you can have until more varaibles comes in i.e more energy going into the Northern arm of the jet - I will be interested to see the METO update shortly, as their model is bullish about milder Swerlies from T120.

Yes thats a good point Ian, theres only so many opportunities to get the easterly in. And theres not a middle ground here, if the UKMO verifies and the trend it shows can bring only one thing, an elongated trough to the north and high pressure sinking south into Europe and mild sw'erlies, on the other hand if the models follow the GFS/GEM and ECM much colder conditions arrive. I don't see a halfway house and to a certain extent this could well determine how the rest of the winter plays out. So its no understatement to say that events upto 144hrs could not be more important this evening. Actually IMO we'll know by 96hrs whether to turn the heating off or get the woolie hat and ear muffs out!

[Dorset_Weather]

An interesting post from Ian Fergusson in the south west forum:

Hi, just a very quick interjection to offer clarification, as I think there's a potential misreading developing here of the UKMO viewpoint regarding the (longer) medium-range prospects.

Firstly, I should stress that (in advance of any interesting / noteworthy weather) the short-term NAE and high-res forecasts for our region are regularly fleshed-out on my blog (such as updates through yesterday - see http://bbc.co.uk/ianfergusson). However in my last entry, I've also started a 'generalist' style dip into how the medium-range guys at Exeter are assessing the 6-15 day modelling.

Rather than me blather-on about it here, let me quote directly some salient expert thoughts from our latest (late morning) detailed Met Office briefing. I trust these 'snipped' passages offer suitable clarification on the collective thinking down in Exeter....

"4. Trend For Days 10-15: Lamb weather types are unbiased easterly with a below average Shannon entropy. Hence probably slightly higher confidence in this period than for day 6 to 7.5. Discussion: The deterministic models are well split for day 6 to 7, and the ensemble means have a col near the UK (showing a wide spread of solutions). Thus a very messy, temporary breakdown from the colder weather on day 6 to 7 (with low confidence in all detail). However, all ensembles want to bring back a southeasterly during day 8 to 10. Confidence is thus moderate for a return to a more continental airflow with a drop in temperatures. If anything, the signal for day 10 to 15 is even stronger, and backs the flow more to an easterly."

Best

Ian

[Nick F]

I've been watching the models for the past 2-3 years on NW and can't remember a period where there's been so much uncertaintly and chopping & changing in the output! It's certainly been a different winter this time around. However, I really can't understand why we bother looking at any charts beyond +96hrs because they rarely verify! Some of the posts yesterday showing blinding Easterly flows and 510's over the entire UK were just out of this world - literally! They raise expectations to the point of frenzy and then the very next morning everything goes pear-shaped and people are totally gutted and depressed. Why?

Ignoring anything past t+96 is never going to happen, besides we can pick out broad trends in FI - seeing if operational runs are likely or not when comparing them with the ENS mean and background teleconnection signal for likely upper flow and blocking patterns caused by warmings from aloft. Many seasoned members are wary of getting expectations too high when shown charts like those from yesterday's 18z GFS, though I appreciate some newbies maybe drawn into taking charts literally.

However, in the great scheme of the weather likely to come in early Feb for the UK, i still think there's a greater chance that it will remain cold with a continental flow dominating, how cold and snowy is less certain though.

[Snowyowl9]

Well with this mornings continued disagreement i say bring on 4 pm when the 12z starts to come out, maybe then we may see one of the models back down, hopefully the UKMO.

fingers crossed

SM06

UKMO last week went for a full cold easterly and that never came off.

GFS didn`t nor ECM in the end.

http://www.wzkarten.de/pics/Recm1201.gif

Seems more likely of an undercutting low coming to me with the jet further south then the easterly will come that way.

GFS 0z run went for that.

ECM is more slacker but does come to an easterly more E/SE in the end.

[cooling climate]

I can't see how its "nailed"...

The UKMO wants to bring the Atlantic back in and has done for the past few runs, the ECM isn't great but not exactly mild while the GEM only brings something noteworthy in towards the end of its run.

I did say IMO with regard to what I believe will happen looking at all of the indices and northern

hemisphere circulation pattern. The three main models do not agree I know but as I also explained

in a post this morning I basically think the UKMO is wrong.

The signs for cold far, far outweight the signs for stalemate or milder weather.

Of course you and other posters will look at all the data and models and may well reach a

different conclusion that is part and parcel of the fun of it and right or wrong we take what

we have learned and move on. Cheers.

[Frosty.]

An interesting post from Ian Fergusson in the south west forum:

Hi, just a very quick interjection to offer clarification, as I think there's a potential misreading developing here of the UKMO viewpoint regarding the (longer) medium-range prospects.

Firstly, I should stress that (in advance of any interesting / noteworthy weather) the short-term NAE and high-res forecasts for our region are regularly fleshed-out on my blog (such as updates through yesterday - see http://bbc.co.uk/ianfergusson). However in my last entry, I've also started a 'generalist' style dip into how the medium-range guys at Exeter are assessing the 6-15 day modelling.

Rather than me blather-on about it here, let me quote directly some salient expert thoughts from our latest (late morning) detailed Met Office briefing. I trust these 'snipped' passages offer suitable clarification on the collective thinking down in Exeter....

"4. Trend For Days 10-15: Lamb weather types are unbiased easterly with a below average Shannon entropy. Hence probably slightly higher confidence in this period than for day 6 to 7.5. Discussion: The deterministic models are well split for day 6 to 7, and the ensemble means have a col near the UK (showing a wide spread of solutions). Thus a very messy, temporary breakdown from the colder weather on day 6 to 7 (with low confidence in all detail). However, all ensembles want to bring back a southeasterly during day 8 to 10. Confidence is thus moderate for a return to a more continental airflow with a drop in temperatures. If anything, the signal for day 10 to 15 is even stronger, and backs the flow more to an easterly."

Best

Ian

Thanks for the update hazard

It sounds encouraging to me and as the models continue to try and get a firmer grip of the crucial day 6 and 7. Looks cold until then and hopefully beyond then, Ian is usually spot on.

Edited January 30, 2010 by Frosty039

[Ian Fergusson]

However, in the great scheme of the weather likely to come in early Feb for the UK, i still think it will remain cold with a continental flow dominating, how cold and snowy is less certain though.

Hi Nick - I think your final sentence says it all.

Id add that having seen a section of my blog cited above on this thread, it must be stressed that it is, obviously, a very moveable feast (that blog entry was written based directly on detailed UKMO guidance from early yesterday, and we've since seen further briefings - part of which also cited above on this thread - albeit the general theme remains very much as you summarise above).

I tend to stick within the bounds of the nowcast/ short-range / NAE window on my blog; I'd urge any of you on this thread with technical interests in the longer-range output to visit my colleague Paul Hudson's blog instead - see http://bbc.co.uk/paulhudson

Best wishes to you all -

Ian

[karyo]

I know what you mean but is it a case of the GFS not picking it up or some of the others picking up what won't be there?

I agree with what you say! I look at the models for trends rather than specifics and the trend so far today is not good, i.e. reduced chance for the easterly to develop as there is a shift towards the UKMO scenario, whether that is from some operationals or ensembles. But as you say, it could be that the signal that has been picked is wrong. I'd love this to be the case and either way, the 12z's will/should show a clearer picture.

Karyo

[weather eater]

I agree karyo.

I think its worth noting no matter what ecm gfs gem and the kitchen sink show,if ukmo is not on board then forget it.

We had this in 2005,exactly the same thing,every model was going for a big Easterly but the ukmo said no and guess what happened.I feel there is a lot of dressing up of the models this morning when most seasoned observers know pretty much where this is going.

My confidence in an easterly has gone down to about 10%,and thats being generous.

HD lets be honest if it was the GFS not going for the easterly you would believe that, if it was the ECM you would believe that, lets face it you’re a pessimist at heart. However I would say that the obvious trend at this point of time is for an easterly of some sort. At the range we are talking about the 6th to the 8th for the easterly to form, I would be very surprised to see full model agreement, I can't understand for the life of me why some members seem surprised by this, anyone would think the models are exhibiting some sort of strange behaviour.

[nick sussex]

Well the confusion continues with the UKMO further outlook, modelling wise this backs the GFS 06hrs run with a shortwave heading se'wards and colder easterlies returning! However even though the UKMO obviously have low confidence in their raw output we need this to move this evening towards the other main models.

[Snowstorm1]

YESS GETTIN MET OFFICE DONT AGREE WITH THEIR OWN MODEL ON THE UPDATE COLD IN THE EAST...

Did anybody here that sigh of relief?

Anyways very important 12z this evening its rather going to be prams out the pram or tears of joy....

Edited January 30, 2010 by Snowstorm1

[PubliusEnigma]

I am not pleased with this morning's output! A definate shift towards the UKMO scenario by the ECM operational and the GFS ensembles: http://www.netweather.tv/index.cgi?action=ensviewer;sess=

I think the gfs hasn't picked a signal for increased Atlantic energy and continues to show cold outputs.

I am expecting this signal to be picked by all models by the end of today!

Karyo

Indeed the GFS always seems to underplay the return of the Atlantic. I'm convinved the cold will return but not

until the end of Feb, but it could well last through the entire month of March. We need a mild reload to clear the atmosphere so that the cold can have another shot. At the moment we are stuck in southerly nothingness.. Sometimes rather cold othertimes a little milder.

[Frosty.]

Well the confusion continues with the UKMO further outlook, modelling wise this backs the GFS 06hrs run with a shortwave heading se'wards and colder easterlies returning! However even though the UKMO obviously have low confidence in their raw output we need this to move this evening towards the other main models.

I can understand your caution nick but that has to be a huge step in the right direction, the 6z is a stonking run for cold and snow, almost as good as the 18z last night. It also fits with what Fred has been saying

Edited January 30, 2010 by Frosty039

[Shunter]

Nothing spectacular about them at all. Am I surpised? Nope.

Slightly cooler 06z ensembles for London than the 00z run.

http://85.25.71.112/wz/pics/MT8_London_ens.png

Still a big split though at T96.......mild or Cold ??

[nick sussex]

YESS GETTIN MET OFFICE DONT AGREE WITH THEIR OWN MODEL ON THE UPDATE COLD IN THE EAST...

Just because they don't have confidence in their raw output doesn't mean it's wrong,we should bear this in mind, there have been similar situations in the past where their model refused to back an easterly and their further outlooks went with the other models but eventually the ukmo output was proved correct.

It doesn't have much support from the other models but until it backs down and its raw output keeps the energy further west then we need to take this into account before breaking out the champagne, i criticized the ukmo raw output as being wrong last night and expected it to back down this morning but then woke up to find it still the same! so I for one refuse to go down that road again!

[AderynCoch]

However I would say that the obvious trend at this point of time is for an easterly of some sort.

Agreed. The trend exists and has done for some days now.

How long do we have to wait before an easterly of some sort becomes nailed on? Obviously the magic runs the GFS keeps pumping out should be taken with a massive pinch of salt, but the fact such scenarios are even being hinted at should be telling us something is brewing.

[Ben_Cambs]

IMO ECM 12z this afternoon will be very important. Nice to see the METO outlook for the 4th day in a row back off their raw output. Tonight we will want ECM to back away from 00z and leave UKMO on its own again. And surely if it happens UKMO wouldnt be able to stay on its own for much longer. Ive found in the past few days that the 12z especially in ECM have been much better than the 0z, some sort of trend IMO. Well a very important afternoon and evening for model output to say the least

[PubliusEnigma]

Slightly cooler 06z ensembles for London than the 00z run.

http://85.25.71.112/wz/pics/MT8_London_ens.png

Still a big split though at T96.......mild or Cold ??

Icant fathom this out. The met o outlook says cold in the east for next 15 days. Yet the faxs show Southwesterlies and

the beginnings of a bartlett forming just off the coast of SE France. Someones got it wrong..

[Tim Bland]

Slightly cooler 06z ensembles for London than the 00z run.

http://85.25.71.112/wz/pics/MT8_London_ens.png

Still a big split though at T96.......mild or Cold ??

Overall the ensembles agree on a cooling trend with the 850 mean below -5. Senior metoffice forecasters not going with UKMO model in the extended outlook so all still to play for. I've lots count though of the number of times the extended outlook has ended with Easterly winds in the last few weeks and it never comes to fruition. I would say 50% for a true blast from the east. 25% chance of cold and dry SE winds and 25% return of the atlantic. Lets hope the ECM and UKMO trend towards the GFS tonight!

[billy]

Well the confusion continues with the UKMO further outlook, modelling wise this backs the GFS 06hrs run with a shortwave heading se'wards and colder easterlies returning! However even though the UKMO obviously have low confidence in their raw output we need this to move this evening towards the other main models.

Yes Nick its a bit confusing that meto update especially as last nights fax charts appeared to follow the ukmo raw output . I dont think they have any more idea about whats going to happen next week either

[Mark Bayley]

I did say IMO with regard to what I believe will happen looking at all of the indices and northern

hemisphere circulation pattern. The three main models do not agree I know but as I also explained

in a post this morning I basically think the UKMO is wrong.

The signs for cold far, far outweight the signs for stalemate or milder weather.

Of course you and other posters will look at all the data and models and may well reach a

different conclusion that is part and parcel of the fun of it and right or wrong we take what

we have learned and move on. Cheers.

To further back your thoughts the met office seem to dismiss the UKMO model and agree with a flow from the South East or East.

http://www.metoffice...st_alltext.html

I think some sort of flow from the South East or East is very likely. Just how cold is up to debate. Hopefully the GFS is nearer the truth, which is colder and snowier. The ECM would probably be cool/cold but unfortunately not much snow. I would much prefer to the UKMO model to trend towards the GFS this evening. Overall the signals and models do favour a flow from the South East/East rather than the UKMO version.

I just wouldn't say I'm as confident as you, yet

Edited January 30, 2010 by mark bayley