Model Output Discussion - Early November Onwards

[Frosty.]

Hi Karl

To me the stalemate we've had points the way forward inasmuch the jet is not roaring to our north and hasn't been for 3 years now and the PV is not defaulting to Greenland. We won't see this current pattern maintain for more than 2 weeks more IMO. My workings are for the jet to kick energy south of UK latter part of Nov with northern blocking in place. My only thoughts now are turning towards does it maintain a cold to very cold pattern or does it lurch to and fro as suggested RJS. Currently I favour RJS thoughts BUT I have said [even since summer] that I anticipate an extreme month again this winter so if we do get a cold pattern change it may well dig in and hold like this current pattern has.

I agree with Big Steve M, the teles have their place, but its just a place and they are not individual drivers and indeed may well be responses to a main driver.

Yes its mild for a week ahead at least, but thats as far as I'll go.

BFTP

It's very encouraging to read your views as well as Steve's about a much awaited pattern change and hopefully there will be more cold showing in the upcoming ensembles, i'm fed up of these 15-18c temps in november but it looks as though after a brief dip in temps, it will become warm again later next week.

[damianslaw]

Reliable timeframe - same old story... trough stuck out to our west with heights remaining strong to our east changing slightly in orientation but only to revert back to what we have seen much of this week - so a continuation in the very mild conditions for the foreseeable future - at least until next weekend.

Longer term - yes I agree suggestions from GFS of a possible significant pattern change, thanks to changes over Canada and pressure rising over Greenland. GFS does tend to perform much better than ECM when it comes to developments to our NW - if it continues to show such a pattern change in the coming days, then yes the second half of November could be very different to the first half with a much colder period of weather.

One positive is the position of the PV - there are no signs of it moving into the area between Iceland and Greenland, the jet at this time of year often roars to the north of scotland, at present it is very sluggish and weak - a very encouraging building block for cold weather if the pattern change suggested by GFS verifies.

[chionomaniac]

Evening All-

For the third day running I have to disagree with pretty much everything that has been posted today-

Everyone seems to have jumped on the bandwagon that nothings going to change in the near future & that mild is locked into the NW part of Europe for the next X weeks-

Whether you look at models, MJO forecasts, The PV, Stratosphere etc they all have their place- however none of them rarely 'lead' the way in asserting an iminent pattern change ( maybe with the exception of a Major warming in the Stratosphere)

So far this autumn we have indeed been locked into an extreme pattern- however its not an extremely zonal pattern- we have seen the jet come up against a brick wall in the form of a solid euro block-

The positves out of this is that a blocking pattern for autumn when the jet should be at its most zonal is encouraging- also IIRC a + VE NAO in Oct has a Higher correlation to a -NAO in Winter than a -VE NAO does in oct-

Also if you look at the PV is WAY WAY over the other side of the hemisphere-

The reason the euro block has sat there has been a weak jet flow which has seen a fairly uniform split - with some energy digging south, & some flowing over the top- allowing that circular shape-

The flow of the jet out of America needs to change if we are going to see things change- which I believe they will- Im not promising an instant change to bitter weather- however one fundemental thing that looks to change in 7/8 days over towards canada where the flow starts coming round the pole & driving South -

If you look from the top down at the very LATEST ECM

http://www.meteociel...H1-168.GIF?04-0

You see that inland runner up into central Canada- that will support height rises over western Greenland-

When you get LP systems tracking that way out of Central canada the directly linked teleconnection pattern is to start to see heights fall over scandi-

THe GFS takes the fledgling greenland high pressure at 168 - holds it in situ & kicks low pressure south through Scandi- this pattern of Hp over greenland & low over Scandi then supports LP in the atlantic towards the azores & high pressure getting squeezed out in Europe-

The rub comes if we can get enough of an inland track over canada at day 7/8 & how much low pressure can we squeeze towards central europe=

Its the ANGLE that inland runner takes thats KEY to the ridging into greenland- gfs very amplifed / ecm slightly flatter

A pattern change is looming- those ignoring it will only be able to do that for another day or so

S

Hi Steve,

What you say here makes sense but it is a long way out to be sure that any pattern change is definite. GP touched upon earlier the main driver to any pattern change - that is the current positive Asian mountain torque. Any pattern change won't just come out of thin air and there will always be a driver that has a knock on affect to produce it - whether it be a strong MJO wave or stratospheric influence or mountain torque event. Now, mountain torques have been shown to modify the existing Rossby wave pattern and therefore induce a change to a new Rossby wave pattern. They have been shown to affect the AO and NAO in some studies.

The question remains regarding whether the current mountain torque event will be enough to rearrange the Rossby wave pattern to induce the changes that you suggest. I suspect that the pattern will be modified slightly with a slight eastward or southeastward shift of the current Atlantic trough but I do not think it will bring about wholesale changes to completely reverse the pattern that we are in. Not yet, anyway. I think that after a slight modification to the current pattern then we will be in a stronger position for a more permanent pattern change.

The precursor to the pattern change that you suggest is still very much in FI and can still leave us on the warm side of any Atlantic trough. So until we see definitive changes upstream in the reliable timeframe backed up by the lower stratospheric and other teleconnective input I am certainly very cautious about seeing any major change within 2 weeks and probably for the best part of the month.

c

[Grimsby Snow Lover]

It's very encouraging to read your views as well as Steve's about a much awaited pattern change and hopefully there will be more cold showing in the upcoming ensembles, i'm fed up of these 15-18c temps in november but it looks as though after a brief dip in temps, it will become warm again later next week.

I have just looked through the GFS temperature charts and was expecting to see 16/17 degrees, I only could see 15 as a max in the south of the country. I admit this is above average by around 2/3degrees but I wouldn't call them warm especially if there is a strond wind and rain around . However if the ECM verifies then you could be quite right. Which model do you feel has a stronger grip on next weeks pressure patterns? I hope this doesn't come across as a critisism Im just learning and would appreciate it if you could explain how you make your conclusions. Thanks GSL

[Isolated Frost]

During the first half of November, daytime maxima in lowland britain range from 8c in northern Scotland to 12c in Southern England, so temperatures by day are markedly above generally, apart from during rPm incursions. GSL- what are the minima for the next few days? Minima in lowland Britain in the first half range from 2c in Northern Scotland to 6c in Southern England. I'd imagine a good 5-8c above average nationwide usually when it comes to minima (again apart from rPm and cloudier, cooler ne'ly incursions.

[Grimsby Snow Lover]

During the first half of November, daytime maxima in lowland britain range from 8c in northern Scotland to 12c in Southern England, so temperatures by day are markedly above generally, apart from during rPm incursions. GSL- what are the minima for the next few days? Minima in lowland Britain in the first half range from 2c in Northern Scotland to 6c in Southern England. I'd imagine a good 5-8c above average nationwide usually when it comes to minima (again apart from rPm and cloudier, cooler ne'ly incursions.

Thanks for the information IF. I was just basing my info on temperatures on averages from MSN - probably not the best I know. Regarding average temps I had forgotten to consider night time minima so thanks for the pointer

[Geordiesnow]

Looks like in the shorterm there could be a 3 way split developing with cloudy damp conditions for some Southern and Eastern areas whilst the further North and West should be more sunnier and the far North of Scotland cloudier and damp and cooler. Early next week it looks like the cloudy conditions that some southern and eastern areas will face will spread northwards whilst Northern Scotland could actually brighten up.

I think because of the cloudy conditions, temps will be lower than we are used two but still mild for the time of year(9-11C generally), if we pick up more of a SSW'ly stream then the temps will be higher but the mildness continues but perhaps nothing exceptional.

[peterf]

i think everyone is simply guessing as to any change.

more time needed on this one i think.

[feb1991blizzard]

Interesting T276 on the GFS 18z.

http://www.meteociel...&ech=276&mode=0

Atlantic trough ruined everything again though. Im getting really annoyed by this trough to the west and i cant see me becoming any more relaxed for at least the next 2-3 weeks, probably into december, unless i just take a month off, easier said than done though.

Edited November 4, 2011 by feb1991blizzard

[The watcher]

i think everyone is simply guessing as to any change.

more time needed on this one i think.

There's guesses and there's educated guesses. Chionamaniac and quite a few others have explained things in a way that isn't guesswork.

[Weathizard]

Minor differences between latest ECM and GFS, both pointing to very unusual warmth around 216/240hr+, could these charts potentially break some records?

[peterf]

well if it dosen't occur, it was a guess or a wrong call.i accept that but it seems some folk are already getting wound up about winter and we havn't even got autumn out of the way.

no harm in having a guess as to what may or may not happen.but lets remember at this NOW present time thats all these predictions are.

There's guesses and there's educated guesses. Chionamaniac and quite a few others have explained things in a way that isn't guesswork.

would any of them put their house on their predictions?

i think not.

Edited November 4, 2011 by peterf

[feb1991blizzard]

well if it dosen't occur, it was a guess or a wrong call.i accept that but it seems some folk are already getting wound up about winter and we havn't even got autumn out of the way.

no harm in having a guess as to what may or may not happen.but lets remember at this NOW present time thats all these predictions are.

would any of them put their house on their predictions?

i think not.

I would put my life on the fact that i wont see a single flake of snow here before the last week in November.

[Snowstorm1]

I would put my life on the fact that i wont see a single flake of snow here before the last week in November.

I wouldn't go that far...

[kold weather]

Minor differences between latest ECM and GFS, both pointing to very unusual warmth around 216/240hr+, could these charts potentially break some records?

18z GFS probably not, the 12z ECM would probably be a close run thing depending on cloud cover amounts, etc...

[Thundery wintry showers]

In my opinion the current set of teleconnection signals and model outputs don't point towards any sort of dramatic pattern change in the next 10-15 days, but we are likely to see the trough in the Atlantic weaken with rising pressure over and to the north of Britain. I'm currently envisaging a very dry November for many parts of the country. I can't rule out the possibility of snowy outbreaks in the second half of November, but it strikes me as very unlikely that anyone on low ground will be seeing any snow this side of the 15th November, and also that if we get any cold spells in the second half of the month the emphasis will probably be on cold and dry rather than cold and snowy.

I don't think we are likely to break any November temperature records, with the generally southerly flow projected for 4-8 days' time having a strong continental influence, but temperatures are set to be well above the long-term average after a brief colder interlude, and in any sunshine it will feel warm. However, while southerlies are a pretty reliable source of sunshine in the summer half-year (anyone remember that hot spell at the end of September?), by November continental Europe is much more prone to persistent banks of cloud and so it is very hard to pinpoint cloud amounts at this range.

[Jason T]

I would put my life on the fact that i wont see a single flake of snow here before the last week in November.

That's a very brave call. What assumption are you calling that on,The current reliable output or FI.

[feb1991blizzard]

That's a very brave call. What assumption are you calling that on,The current reliable output or FI.

A combination of the current operational model output including FI, any ensemble members of either the ECM or the GEFS staunchly staying above the -5 850 hpa temps, thus GEFS mean, ECM mean and spread and NAEFS keep the mean trough to our west and High pressure cell strong to our east right out to day 17, No stratosphere warming either forecast or underway, GPs recent posts suggest any MJO forecasts either against a pattern change or that they will be overidden, TWS monthly forecast, Met office forecast and most other media forecasts suggest no cold weather in November and i would go as far as saying that No widespread potent cold spell is likely until a week into december at the earliest although that is very speculative and wouldnt put my house on that.

[damianslaw]

In my opinion the current set of teleconnection signals and model outputs don't point towards any sort of dramatic pattern change in the next 10-15 days, but we are likely to see the trough in the Atlantic weaken with rising pressure over and to the north of Britain. I'm currently envisaging a very dry November for many parts of the country. I can't rule out the possibility of snowy outbreaks in the second half of November, but it strikes me as very unlikely that anyone on low ground will be seeing any snow this side of the 15th November, and also that if we get any cold spells in the second half of the month the emphasis will probably be on cold and dry rather than cold and snowy.

I don't think we are likely to break any November temperature records, with the generally southerly flow projected for 4-8 days' time having a strong continental influence, but temperatures are set to be well above the long-term average after a brief colder interlude, and in any sunshine it will feel warm. However, while southerlies are a pretty reliable source of sunshine in the summer half-year (anyone remember that hot spell at the end of September?), by November continental Europe is much more prone to persistent banks of cloud and so it is very hard to pinpoint cloud amounts at this range.

Yes cloud cover should scupper chances of any exceptional temps being recorded I suspect - also under such synoptics stubborn fog can become a problem and suppress temps especially where winds fall light. Mid-high teens at best. I can't say I am particularly relishing the type of conditions next week promises - lots of drab dull dank dark conditions - many will be longing for some polar air by the end of next week I suspect just to freshen and brighten things up a bit. At least the next 2-3 days promise fine sunny weather for the northern half of the country, the se for once looks to be worse favoured for sunshine in the coming days.

[feb1991blizzard]

Lol I can just imagine grim reaper rubbing his hands together in anticipation

I cant remember what his preferences are please refresh my memory.

[Cheshire Freeze]

I cant remember what his preferences are please refresh my memory.

I meant the fact you put your life on not seeing a single flake of snow this November

In all seriousness, I can see your point with the synoptic situation that we are currently in; though things can change and I suspect they will.

Edited November 4, 2011 by CreweCold

[ITSY]

so, 12Z GFS illustrated how current synoptics could potentially deliver cold. 18Z illustrates the opposite. = anybody's guess.

[feb1991blizzard]

The fact you put your life on not seeing a single flake of snow this November (jokes)

In all seriousness, I can see your point with the synoptic situation that we are currently in; though things can change and I suspect they will.

I hope your right Crewe and im certainly looking forward to this winter although not as confident as i was a couple of months back, it just looks so stuck to me, it looks as though there is a new permanent feature to our weather in Western Europe - The Atlantic Trough, a bit like the Azores high or the PV, it just limpets itself and when it does weaken, another one just phases it, even if it ejected a shortwave deep into spain, i still think it wouldnt guarantee us a potent cold spell but at least that would set the ball rolling.

[Snowmadsam]

so, 12Z GFS illustrated how current synoptics could potentially deliver cold. 18Z illustrates the opposite. = anybody's guess.

Wonder what the 00z will show then....

[summer blizzard]

GFS18z is a poor run and pretty implausible in late FI.

We get the split in the Jet Stream with most of the energy in the northern low which is fair enough however this low is further east then other runs have indicated and as such we get a zonal flow which again is fair enough.

The implausible bit is that we get a Greenland High out of no where from a zonal pattern.

I don't think this will be the actual solution.