Model Output Discussion 18th Nov.2013-12z onwards.

[Tamara]

But at the moment cc, the extended ECM ens and gefs/naefs all take that transferred energy back towards Canada in two weeks, spreading the vortex across the pole.

It is just a forecast like all the others, but I think there is a lot of credence with this looking at the overall pattern - and following on from what was said yesterday this seems the likely evolution and why, at least as far as I am concerned, I am not expecting much from this next suggested amplification and any colder spread of air looks to be very transitory and I am not sure how far south it will get. Whatever appealing charts may be suggested in some FI modelling, I think are flattering to deceive.

 

Not a popular view I know

 

Edit: Just to add that was an excellent descriptive and well illustrated post from Nick S up the page

Edited November 24, 2013 by Tamara תָּמָר

[Frosty.]

The GFS 06z op run reinforces my view that we will be entering a cycle of wintry reloads from the nw / n as time goes on, some very encouraging signs this morning with the gem remaining solid with it's colder wintry further outlook, the ecm 00z mean and op which are trending the same way and now this run, some very frosty weather and a risk of snow.

[Summer Sun]

GFS is slowly starting to show temperatures getting slightly above normal again for the northern half of the UK, the coldest part of the UK over the next 8 days is likely to be the south

 

 

Expected temperatures over the next 8 days

 

 

Average temperatures for the time of year

 

Edited November 24, 2013 by Summer Sun

[Cloud 10]

FWIW,the gefs has the MJO on the move into phase 1 as we enter December...

 

 

 

....which gives the following composite anomaly chart (flipped for better UK view)...

 

 

 

GEFS out on its own at the moment on this one.

 

CPC - Climate Weather Linkage: Madden - Julian Oscillation

 

 

[stewfox]

Things can and do change but it looks to me like it may be a Bartlett style few weeks in early December at this point (or something similar). Not saying we are looking at this for months or anything like that (though like some others on here I recall 1988 and am still traumatised by that winter :-) ).06z run rolling out though so as always waiting to be proved wrong.Jason

 

What charts are you referring to , where you see a Bartlett syle set up for the first few weeks of December ?

[Cleeve Hill]

With the HP close by, the next working week is going to be cool and grey (hopefully the odd frosty morning and blue skies depending where you live) and certainly no sign of anything wet and windy  . All very autumnally really.

 

Interesting to see what happens after the next 10 days as it is rare to see such a long period of mid atlantic blocking. Different synoptics once again to what we have been used to in past autumns/early winters.

[Summer Sun]

What charts are you referring to , where you see a Bartlett syle set up for the first few weeks of December ?

 

 I think the key to Jason's post is "maybe"

 

We'll have a lot of ups and downs over the coming weeks

 

Not a proper Bartlett but this is what the 00z had

 

Edited November 24, 2013 by Summer Sun

[Snowyowl9]

 I think the key to Jason's post is "maybe"

 

We'll have a lot of ups and downs over the coming weeks

 

Not a proper Bartlett but this is what the 00z had

 

The GFS 0z run showed the high more close to the west/SW it did show a cold shot into the NE on day 10.

Looking mostly settled anyway although cooler W- NW-lys at times the charts I`m looking at.

[Catacol]

 

couple of things to watch

 

http://www.solarham.net/

 

http://www.swpc.noaa...s_timeline.html

 

solar activity has finally started to go quiet again and hope it stays that way

 

plus nao looks to go negative as we go into december

 

http://www.newx-forecasts.com/nao.html

 

 

 Have noticed also that the stratosphere temp is starting rapid cooling, Ironically the pattern is almost similar to last years.

 

 

In general the ozone is contained within the stratosphere, The stratosphere heats up from the level of UV from the Sun etc, As  solar activity is slowing down so this will affect the temp within the stratosphere ie rapid cooling.

 

 

 

None of which is especially great for a severe cold outbreak. NAO forecast unremarkable, ozone below average, vortex powered up, wave activity moderate at best, SST profile in the North Atlantic rather stagnant though still favouring the atlantic ridge.

 

Ha - you wouldnt know I was a coldie... :-) but sometimes I think some realism is important.

 

However it is not all bad. Personally I dont see a Euro high developing and that means an average December.

 

We do need something, however, to happen in the strat in the next 6 - 8 weeks because otherwise I could see a Euro high situation develop for late Jan and into Feb. That would obviously be very, very bad....

[shedhead]

Once again the latest outputs keep HP over or close to the UK in the short/medium term, so if dry, quiet weather with the risk of overnight frost and fog where skies clear floats your boat, then it's happy days.  When looking beyond this time next week, it looks to me as though the purveyors of rose coloured glasses have enjoyed another profitable 24-36hrs in here, because even next weekends so called 'cold plunge' already looks like being a very insipid affair.

 

IMHO the main straws to clutch today are still little sign of raging zonality developing and for the south at least, a continuation of the largely quite, settled weather. However, as things currently stand a return to proper cold as we move into Dec still looks a as far away as ever.

 

GFS

 

 

 

 

ECM

 

 

 

 

 

 

UKMO

Edited November 24, 2013 by shedhead

[SMU]

Afternoon All-

 

Well some continued encouraging times from 'some' of the models, - most notably the GEM & the ECM, although quite a way out in the timeframes.

 

The Aleutian high playing a big part in supporting a decent cross polar 'push' of very cold air, - this looks to decend on Scandi at a rate of knots in the day 8-9 timeframe however question marks as to whether it can fully reach the UK.

 

The GEM is the most highly amplified with the big Aleutian high + deep PNA pattern & retrogression -NAO leading to the vortex split in 2 from a classic 2 wave pattern.

http://modeles.meteociel.fr/modeles/gem/runs/2013112400/gemnh-0-240.png?00

 

ECM has similarities with this although not as amplified across the atlantic.

http://www.meteociel.fr/modeles/ecmwf/runs/2013112400/ECH1-240.GIF?24-12

 

Perhaps time to reflect over the next couple of days-  a November forecast to be above average - will more than likely turn out below normal, also a month that's seen bouts of South westerly flows, however they have diminished as the months progressed & moved towards a more Northwesterly flow -

Also we have seen no high level blocking so for season to date- however 'suggestions' that things heigher heights will creep into the pole day 8 onwards -

 

Taking the models at face value today excluding the GFS I would say reasonably balanced for the opening to winter 'proper' - nothing spectacularly cold, however by the same token nothing really mild either.

Fingers crossed that the aleution high can make inroads into the pole as the GEMs suggested & start to force a more substantial break in the low heights over the central pole.

 

If its cold & snow potential your looking for I suggest day 10-12 being the next window of opportunity.........

 

Shades of December 81 still ringing in my mind.

 

 

S

Edited November 24, 2013 by Steve Murr

[Frosty.]

The GEFS 06z perturbations have a few very wintry runs further on, including the control run which ends with it about to send an arctic blast of some magnitude down across the uk, very encouraging signs today from ecm, gem, 6z op and these shown here.

[Methuselah]

The GEFS 06z perturbations have a few very wintry runs further on, including the control run which ends with it about to send an arctic blast of some magnitude down across the uk, very encouraging signs today from ecm, gem, 6z op and these shown here.

Indeed, Frosty. But individual perturbations are (by their very nature) even less likely to be correct than the Operational...

Edited November 24, 2013 by A Boy Named Sue

[Ali1977]

I think, if we are going to get some gold weather in 10 days or so the GFS should start to show this soon. It has stuck to its guns for a fair few days now and does not want to change its mind.

[Frosty.]

Indeed, Frosty. But individual perturbations are (by their very nature) even less likely to be correct than the Operational...

True pete but I think the positives from a cold perspective outweigh the negatives so far today, the trend to colder zonality looks to be firming up once the current settled spell is eroded by the end of the week onwards.

Edited November 24, 2013 by Frosty.

[Snowman.]

CFS is in 'slight' agreement with the ECM.

 

 

 

Main thing there is pressure systems are running south rather than over which can only be good news. Also it looks keen on dropping the troughs south.

 

 

 

GFS is out on a limb here keeping a lot of Energy in Canada.

 

 

 

The CFS does this at T300

 

Sends everything south giving the UK some very wet weather however it allows for pressure to rise north.

 

By 384 we have a very weak ridge in the Atlantic with a trough over Nothern Europe.

 

One thing leads to another as the trough in the Atlantic is swallowed by the low exiting the eastern seaboard with leads to height rises over the UK which is cut off by a trough approaching from the East..

 

 

Next thing you know there's an Easterly with some very cold uppers.

 

Now we should focus more on lows dropping down which could be a trigger then with some amplification west we could be in the bag.

 

Just need the purples to leave the North which is probably the hardest part.

 

 

 

Nothing here is set in stone but the CFS is keen on giving us something, what that is and how its performed is a different matter.

Edited November 24, 2013 by SN0WM4N

[Catacol]

MJO forecast interesting, Currently forecast to move into low phase 5 moving to 6. 

 

 

 

November composites for phase 5 are not at all good

 

 

 

but the contrast with phase 6 is stark:

 

 

 

So in the midst of sobering reality if the mjo forecast comes off it reinforces the sense that any SW coming off the back of our collapsing high will be short lived as pressure starts to build back into the atlantic.

Edited November 24, 2013 by Catacol_Highlander

[Joe Levy]

CFS is in 'slight' agreement with the ECM.

 

 

 

Main thing there is pressure systems are running south rather than over which can only be good news. Also it looks keen on dropping the troughs south.

 

 

 

GFS is out on a limb here keeping a lot of Energy in Canada.

 

 

 

The CFS does this at T300

 

Sends everything south giving the UK some very wet weather however it allows for pressure to rise north.

 

By 384 we have a very weak ridge in the Atlantic with a trough over Nothern Europe.

 

One thing leads to another as the trough in the Atlantic is swallowed by the low exiting the eastern seaboard with leads to height rises over the UK which is cut off by a trough approaching from the East..

 

 

Next thing you know there's an Easterly with some very cold uppers.

 

Now we should focus more on lows dropping down which could be a trigger then with some amplification west we could be in the bag.

 

Just need the purples to leave the North which is probably the hardest part.

 

 

 

Nothing here is set in stone but the CFS is keen on giving us something, what that is and how its performed is a different matter.

That's yesterday's run. Though today's 1 month run still has some good opportunities for cold in the not too distant future.

[Mucka]

I think, if we are going to get some gold weather in 10 days or so the GFS should start to show this soon. It has stuck to its guns for a fair few days now and does not want to change its mind.

 

I think the 06z run is an aberration, going against this mornings advances (moving the pattern West) and what the other models are generally predicting. This mornings 00z was a sign it is waking up and I expect the 12z to once again be better and its ensemble mean to resemble 00z than the 06z.

In fact if I were to stick my neck out I would say the 06z set will be among the "warmest" we see in any future runs from the 29th.

 

That said I agree with some of the excellent posts this morning that cold prospects are still limited, especially away from the NW but at the same time the door is not bolted shut and a pattern change with high pressure being displaced West allowing for some more unsettled weather and colder incursions seems likely early December as was discussed some time ago based on interpretation of a weak signal within GFS ensembles.

Edited November 24, 2013 by Mucka

[fergieweather]

True pete but I think the positives from a cold perspective outweigh the negatives so far today, the trend to colder zonality looks to be firming up once the current settled spell is eroded by the end of the week onwards.

Yup, UKMO M-R Desk's latest assessment agrees with the gradual return to westerly mobility (as they've favoured for some days now, as the DECIDER flow diagnostics signal strengthened from some initial tentative signs). However they note that in the S at least, temps *could* go above average in the trend period (10-15d) whereas some snow in N would be in keeping with climatological norm. However, key point they stress is potential for significant pattern amplification across the Atlantic and as such, the Dep Ch Forecaster prudently notes that "a variety of weather types could thus affect the UK."

[shedhead]

Yup, UKMO M-R Desk's latest assessment agrees with the gradual return to westerly mobility (as they've favoured for some days now, as the DECIDER flow diagnostics signal strengthened from some initial tentative signs). However they note that in the S at least, temps *could* go above average in the trend period (10-15d) whereas some snow in N would be in keeping with climatological norm.

However, key point they stress is potential for significant pattern amplification across the Atlantic and as such, the Dep Ch Forecaster prudently notes that "a variety of weather types could thus affect the UK."

Thanks for the update Ian. Perhaps not enough there to make most folk ecstatic, but at least enough to stop them becoming further depressed - note most tho...

[Bradowl]

I think, if we are going to get some gold weather in 10 days or so the GFS should start to show this soon. It has stuck to its guns for a fair few days now and does not want to change its mind.

Here's one hoping for some Gold.

[Newberryone]

I just hope JH is out tonight 

 

Where is the model support ,/ rationale to make such an assumption on 23rd November ??

 

Apart from a small warm blip next week, models are showing very much 'average conditions' out to FI which is around T144/T168

 Apart from a small warm blip next week, models are showing very much 'average conditions' out to FI which is around T144/T168

 

Precisely, as you say, average conditions and so nothing to get too excited about.

[SMU]

Yup, UKMO M-R Desk's latest assessment agrees with the gradual return to westerly mobility (as they've favoured for some days now, as the DECIDER flow diagnostics signal strengthened from some initial tentative signs). However they note that in the S at least, temps *could* go above average in the trend period (10-15d) whereas some snow in N would be in keeping with climatological norm.However, key point they stress is potential for significant pattern amplification across the Atlantic and as such, the Dep Ch Forecaster prudently notes that "a variety of weather types could thus affect the UK."

 

So the decider models 'seeing' amplification in the atlantic which runs in tandem with the Aleutian High-

 

Pattern trending towards Dec 81 would be great!

 

S

[Methuselah]

So the decider models 'seeing' amplification in the atlantic which runs in tandem with the Aleutian High-

 

Pattern trending towards Dec 81 would be great!

 

S

What are the 'decider models', Steve? Will the weather not just do what it does?