Model Output Discussion - cold spell to end Autumn

[Frosty.]

The 6z operational put the building blocks in place, let's hope the 12z runs don't scatter them all over the place again like the 00z snooze fest!..I'm still backing a change back to colder weather from the nw / n following a slightly milder weekend and early next week even if the 12z output says otherwise!..I'm showing defiance!!

Edited November 28, 2017 by Frosty.

[raul_sbd]

53 minutes ago, Ali1977 said:

The update may be better for coldies yet - their models may not have wavered like the GFS/ECM did overnight 

Still says 2.23 on the 28th November last update isn't? or am I looking to the wrong prediction? Could you please point me to the link to the metO update?

Thanks

[The Northern Ramper]

2 hours ago, nick sussex said:

The doctors have detected a pulse! 

Typical just as the priest was called the GFS 06 hrs revives hopes! This occurs because of a slight change over Artic Canada with a more amplified pattern which stops the shortwave appearing to the nw which is now becoming the make or break of the current long winded saga.

You must maintain a clear flow from the UK ridge back towards ne Canada. If you don’t as the upstream amplification works east it amplifies the pattern to the west of the UK which takes shortwave energy to the nw.

In terms of meangate I agree with Weathizard, the mean is not very useful in this set up because the evolution with or without spoiler shortwave is completely different.

 

This could be a classic case of the models picking up a signal, dropping it and then finding it again.

We've just got to hope the extra 6hrs of data the gfs has had is enough for it to have a better handle on the shortwave.

The UKMO (which never bought the original path to cold and was proved correct) is it appears to be leading the way and the more consistent model.

 

Game on

[karlos1983]

NAO looks more negative than positive, but the jury is out a bit.

AO on the other hand..... I'll take the one that's off the scale please 

 

[SLEETY]

That’s correct.The models always want to revert to mild zonal weather ,as that’s the default uk pattern

 

the meto extended always say that as well ,when we are in cold weather,that a return to a mobile pattern is favoured later in the period,or something similar

they always say that

Likewise whenever a model run shows a mild fl always the same posters write off a cold spell because of one mild fl run.It happens every single time.You could put money on that .

 

[cheeky_monkey]

not seen a chart like this in winter for a long time..even though it is at the end of the run...the pacific ridge is pushing right up through Alaska into the Arctic and forcing pressure to rise across Baffin island into Greenland..would be brutally cold here..but IMHO would force the jet even further south across western Europe...making it very cold there too. this kind of chart has appeared a few time on recent runs over a number of days

Edited November 28, 2017 by cheeky_monkey

[knocker]

19 minutes ago, Ramp said:

This could be a classic case of the models picking up a signal, dropping it and then finding it again.

We've just got to hope the extra 6hrs of data the gfs has had is enough for it to have a better handle on the shortwave.

The UKMO (which never bought the original path to cold and was proved correct) is it appears to be leading the way and the more consistent model.

 

Game on

One has also to keep in mind that there is often, with split energy flows, more than one shortwave to contend with. The ecm at 00 for example produced quite an important one from the energy flow/trough from the southern arm.

Edited November 28, 2017 by knocker

[Mucka]

1 hour ago, bluearmy said:

Given the multitude of eps clusters from the 00z suite, I doubt the next runs are going to resolve anything 

Wise words. There is absolutely no coherent signal within the ensembles past day 7.

ECM ensembles retained a cold signal among the scatter until this morning but on the other hand there is still no signal for Atlantic driven weather to settle in.

[Chesil View]

So now we await the 12z GFS to see if there is the slightest hint of run to run consistency on the 06z cold and snowy signal....... I know where my money is. lol

 

Edited November 28, 2017 by Broadmayne blizzard

[karlos1983]

48 minutes ago, karlos1983 said:

NAO looks more negative than positive, but the jury is out a bit.

AO on the other hand..... I'll take the one that's off the scale please 

 

Here's my interpretation of the off the chart -AO member 

Love an underdog me..

Mean while the ICON is rolling out and seems to be dealing with the  Atlantic trouble maker a little better early on.

Edited November 28, 2017 by karlos1983

[Polar Maritime]

A few posts relating to the meto have been Hidden, Once again just model discussion please in here.

Thanks.

[karyo]

13 minutes ago, karlos1983 said:

Here's my interpretation of the off the chart -AO member 

Love an underdog me..

Mean while the ICON is rolling out and seems to be dealing with the  Atlantic trouble maker a little better early on.

It keeps us under high pressure next week with the northerly going to the continent. 

The Atlantic shortwave edges in towards the west in the end of the run. Blocked but boring overall.

[frosty ground]

12 minutes ago, karyo said:

It keeps us under high pressure next week with the northerly going to the continent. 

The Atlantic shortwave edges in towards the west in the end of the run. Blocked but boring overall.

But it has backed the pattern West in comparison to the 0z run?

Edited November 28, 2017 by frosty ground

[karyo]

Just now, frosty ground said:

But it has backer the pattern West in comparison to the 0z run?

It is very different compared to the 0z. Hard to say if it has backed west and the overall placement of high pressure cells is different.

[karlos1983]

2 minutes ago, frosty ground said:

But it has backer the pattern West in comparison to the 0z run?

It's a variation, but no south westerlies showing 

yet....

[sausage]

here goes 12z.

come on follow the 6z please.

please people stop saying winters not started yet. it really doesnt matter if it has or hasnt. if we dont get  the run of play when good synoptics show up then its a waste. winter or not the weather models dont care.

[Frosty.]

1 minute ago, sausage said:

winter or not the weather models dont care.

I didn't think the models had any feelings either way, it's just number crunching data.

[pyrotech]

The current spell of cold weather was influenced by MJO being in Phase  6 and 7 in late October

Early November we moved into CoD

We are now in Phase 4 and that should lead to a  more positive NAO in 15 - 20 days time

The best news is we head into phase 6 i hope in 7 days time and that makes the end of month more interesting (i hope)

So where does that leave the models, they have contrasting signals for next week, The MJO effects of CoD and then the negative AO and possibly NAO.

Unfortunately i feel the NAO will end up being pretty flat and edge towards positive but we have other factors mixed into the fight too. 

Solar minimum (heading towards) and ENSO leaning towards weak La Nina

I am very positive about an interesting winter ahead but for now its looking likely to be Wintry showers in prone places and frost for next week. Then something more mobile and then towards Xmas ( if we can get MJO into phase 6 -7 something wintry and more interesting.

It can take 28 days to get influence on strat above the pole from phase 6 so it all takes a bit of time.

One area of interest is the transition from a blocked pattern to a more mobile pattern and around  12 - 15 days after we moved from CoD into phase 4 that is where will be and that has opportunities albeit temporary. That takes us to 9th - 15th December for transition time.

 

[Summer Sun]

Colder air stays slightly further north at t84 compared to the 06z could see some snow in the Midlands and west into Wales

[MildCarlilse]

Then and now...

[frosty ground]

Getting close to the crunch time, but no real changes to speak of @96 

[Gavin Hannah]

So far the 12z is showing minute differences to our NE ( Canada / Greenland ).  Now comes the interesting phase of chart roll out.  What happens to any shortwaves...

Edited November 28, 2017 by Gavin Hannah

[A.J]

I reckon we're in with the chance here......a bit of run for run comparison, and the 12z GFS run is almost identical the the 06z GFS run at T12....... 

[Summer Sun]

That area of less cold uppers at t114 is narrower on this run

(06z right)

Edited November 28, 2017 by Summer Sun

[karlos1983]

UKMO 96 & 120

not much change in the 24 hour period!!

 

Edited November 28, 2017 by karlos1983