Model output discussion - 1st December onwards

[Methuselah]

23 minutes ago, THE CHOSEN ONE said:

John

i would suggest the signal is to muted at the moment - especially in the ENS MEAN to suggest otherwise - changes are just appearing at day 10 so thats the next landmark-

S

By 'muted' do you mean not really there? IMO, you may be right, or you may not; but I can see no real signal for any dramatic change??

[Bristawl Si]

18 minutes ago, The Enforcer said:

I am not surprised by the model outputs showing a polar vortex-dominated westerly airstream over the UK for the first part of December, as this would be wholly in accordance with the Net-Weather winter forecast, where significant polar vortex disruption isn't expected until during the course of January.

Dare i say it, but not unusual for 1st half of December in most UK Winters; with Scotland and parts of the North receiving the odd PM blast and a little snow.

Bulk standard start to UK Winter imo.

Around 10 days ago i commented about the Euro High also playing a part going forward but i was 'assured' by a prominent member that its influence would wane quite quickly.......hmmm?!

[Mucka]

6 minutes ago, johnholmes said:

Time will tell Steve, however at 10 days NOAA give two bites of the cherry so to speak, 6-10 and 8-14, neither have any signal, however slight, at least to my eyes, of any suggestion YET, of the change you mention. Six days from now who knows, so by 7 December they should, if it is going to occur, be showing something? By then assuming that to be correct then both main models should be showing something similar as well and consistently.

Personally John I would not expect the 6-10 day to show anything at this stage but I would perhaps expect a hint from the 10-14 day of an Atlantic ridge and trough further East?

We are talking day 10+ before any potentially noticeable ridge so it should show in the 10-14 over the next day or two if its a genuine signal and then filter down to the 6-10 day.

At least we have potential obstacle to derail the zonal express to look out for.

 

[Methuselah]

8 minutes ago, Bristle boy said:

Dare i say it, but not unusual for 1st half of December in most UK Winters; with Scotland and parts of the North receiving the odd PM blast and a little snow.

Bulk standard start to UK Winter imo.

Around 10 days ago i commented about the Euro High also playing a part going forward but i was 'assured' by a prominent member that its influence would wane quite quickly.......hmmm?!

I think you are absolutely right BB. Apart from 1981 and 2010, I can't remember a December such as what many folks want - it hardly ever happens!

[Bristawl Si]

44 minutes ago, Ed Stone said:

I think you are absolutely right BB. Apart from 1981 and 2010, I can't remember a December such as what many folks want - it hardly ever happens!

I'd add in 2009 (well 2nd half of Dec). But like u say, apart from these years, a typical December looming really.

Edited December 1, 2015 by Bristle boy

[Methuselah]

59 minutes ago, Bristle boy said:

Dare i say it, but not unusual for 1st half of December in most UK Winters; with Scotland and parts of the North receiving the odd PM blast and a little snow.

Bulk standard start to UK Winter imo.

Around 10 days ago i commented about the Euro High also playing a part going forward but i was 'assured' by a prominent member that its influence would wane quite quickly.......hmmm?!

I think you are absolutely right BB. Apart from 1981 and 2010, I can't remember a December such as what many folks want - it hardly ever happens!

 

 

There's something wrong with the forum here, I know...But - second half of 2009 - I agree...

[Nick F]

I mused last night about the Canadian ridge playing some role in perhaps changing wave lengths and positions as we head towards mid-month, and we see on the 12z GFS in FI and also hints of it happening at the end of the 12z ECMWF too.

Yes, it's a long way off, but the extended EPS mean and control had been hinting over recent runs that the ridge anomaly would drift slowly NE toward Greenland and the far north Atlantic by the middle of the month ... which could lead to an arctic-sourced northerly. The Canadian ridge and southerly storms track over the U.S. keeping cold air from sinking south there is fairly typical El Nino climo for December over North America, as is the very strong polar vortex too with low heights to the north of the UK driving a  strong westerly or southwesterly flow, which look likely to persist until mid-month at least. And although there are signs that the Canadian ridge may drift far enough northeast mid-month to perhaps allow the flow to turn northerly, any mid-Atlantic/S Greenland ridge, I would think, will be temporary, given the Polar Vortex will likely remain strong through much of December.

However, past analogs suggest that a strong Polar Vortex from October through December often doesn't maintain its strength throughout winter. Indeed, using analogs of past strong El Ninos, using the Multivariante Enso Index (MEI) suggest a weaker polar vortex and increased blocking is more likely to occur in Jan-Feb. For the reanalysis plots below for Jan and Feb, I have featured 6 of the strongest El Nino years (not including 1998). Of course these charts don't take in account other drivers in those years which maybe different than early 2016, i.e. QBO and solar activity:

Jan

Feb

This matches fairly well (with regards to the ridge near Greenland and southerly storm track) with the latest Canadian long-range model CanSIPS which gives the 500mb anomaly outlooks for January and February below:

Jan

Feb

As you can see from the 500mb anomalies (red and blue) CanSIPS and reanalysis of the analog years, there is a correlation with the Canadian ridge migrating N and NE in Jan and Feb, the southerly storm track over U.S. and strong Aleutian low typical of El Nino, but also and increasing -NAO signature over Atlantic and Europe.

Unfortunately, no winters repeat similar analog years, and there's the large warm anomalies in the Pacific plus the advanced snow cover in Siberia heading into this winter that may differ from those analog years, as well as the QBO and solar activity. So it's a waiting game to see if the Canadian ridge helps things down the line and also there is the potential pressure exerted on the PV from wave flux activity from the Aleutian low and Siberian high which may break it down in the long run.

Certainly not cause for alarm as we start winter for coldies, though we may have to wait a few weeks for the next nationwide cold snap and perhaps into January for a sustained cold spell the way things are shaping up atm.

Edited December 1, 2015 by Nick F

[knocker]

1 hour ago, Ali1977 said:

That's the 6 to 10 day though isn't it, there could be a large difference if it was just a 10 day anomaly.

Not a huge difference just some with the orientation of the trough and ridging of the HP.  The ext ecm at T360 has the trough dominating the eastern Atlantic, removal of the ridging to the SE and slight ridging into Greenland. Still basically a westerly although not so zonal. Still unsettled over the UK with average temps.

 

[Geordiesnow]

Looking a bit closer to the reliable timeframe and there is the potential of severe gales for the weekend and a lot of wet weather once again. The severe gales could be a talking point and and that little secondary low which gets caught up in the jet stream could turn out into a small but tightly isobar low pressure system. 

In a way I don't think having much signs of blocking is a fully bad thing, too often in recent years, there has been too much blocking and Arctic cold therefore tends to be more diluted so in theory a more stronger vortex could lead to more potent cold if/when the vortex gets disrupted. 

There has been hints of perhaps a bit more blocking heading towards mid month but the models have been up and down in terms of how far Southwards that Arctic high gets but as per usual, never rule anything out. 

[joggs]

Since the upgrade does anybody else have trouble viewing on a mobile(things not fitting on screen)sorry off topic but it's not as easy on a mobile with no comp access

[Paul]

It should be fine now, just some posts are breakng the page at times, will get that sort of thing filtered soon. 

[legritter]

just lost a post ,but just waiting for some eye candy ,certainly not boring  and just a hint from tonights gfs run of something a little cooler ,long way out but interesting  patience is the key gang ,let's hope this post arrives in the right place ,cheers .

[Mucka]

GFS 00z is another no go but also very progressive in FI after showing some promise out to day 10.

 

 

So the window of opportunity still exists but the limited evidence so far is till that any attempted blocking will be overrun. That may change as any potential blocking comes into hi res with any luck.

 

The ensembles are just beginning to pick up on the pattern becoming more amplified around mid December for a time and most of them find a little chill here and there though no real sign of sustained blocking. P20 is probably the pick  but even that only manages temporary MLB. Even so, they are cooler and hopefully we can squeeze at least some wintriness out of a more amplified pattern for as long as it lasts through and beyond mid month.

 

Edited December 2, 2015 by Mucka

[MR EXTREMES]

gem nice for most of europe

[knocker]

The threat of one storm seems to have lifted over the weekend with the low tracking to the north but a perturbation does nip across southern Scotland Saturday evening bringing rain and briefly strong winds to northern England gusting around 60kts. The rest of the run isn't particularly noteworthy except perhaps for a south easterly plunge dragging warm air into England. The second batch of dafs will be out by Xmas at this rate.

Charts weatherbell

 

Edited December 2, 2015 by knocker

[MR EXTREMES]

the north and eastern europe into the freezer greenland very very cold.

be interested to see where that high pressure in the atlantic ends up most likely flattened but nice to see the cold bulding to our north and east if this is correct of coarse.

but the downside would be the temp differences between tm and pm air up and around greenland helping to keep low pressure systems energised.

 

Edited December 2, 2015 by emotional rollercoaster

[Abyss]

45 minutes ago, knocker said:

The second batch of dafs will be out by Xmas at this tate.

 

 

Daffs out by Xmas hmm? Well the Ecm has negative uppers across Scotland and Northern Ireland for 9 out of the next 10 days.

8 out of the next 10 days across Northern England

-4 uppers hugging the South Coast day 9/10

Edited December 2, 2015 by -Bomber-

[Cheshire Freeze]

13 minutes ago, -Bomber- said:

Daffs out by Xmas hmm? Well the Ecm has negative uppers across Scotland and Northern Ireland for 9 out of the next 10 days.

8 out of the next 10 days across Northern England

-4 uppers hugging the South Coast day 9/10

ECM is actually a very good run once again days 9 and 10. Decent amplified ridging west of Greenland at day 10....following on from the 12z of yesterday.

[knocker]

46 minutes ago, -Bomber- said:

Daffs out by Xmas hmm? Well the Ecm has negative uppers across Scotland and Northern Ireland for 9 out of the next 10 days.

8 out of the next 10 days across Northern England

-4 uppers hugging the South Coast day 9/10

 

Streuth negative 850mb temps in December, whatever next. All totally irrelevant of course as the main priority at the moment is total rainfall and the possibility of severe gales.

[Abyss]

7 minutes ago, knocker said:

 

Streuth negative 850mb temps in December, whatever next. All totally irrelevant of course as the main priority at the moment is total rainfall and the possibility of severe gales.

I agree the talk of Daffs in December when the ecm is showing what is showing is totally irrelevant. Didn't stop you from posting it tho. Whatever next, certainly nothing relevant 

Edited December 2, 2015 by -Bomber-

[Nick F]

 

Still the tendency by day 10 on 00z GFS and ECM ops for the Canadian ridge to have an increasing influence over the far NW Atlantic as it stretches east, though it all goes pear-shaped on GFS as it keeps low heights over Greenland. Looking at the northern hemisphere view on ECM, it suggests the trop polar vortex shifting over to Siberia/far NE Europe by day 10 and this opens the gates for poleward height rises over the N American side + there is a small rise over the pole too.

 

 

The troposphere  heights are invariably linked to the stratosphere, yesterday's ECM strat charts show the centre of the PV shifting from Greenland at t+24 towards Barents Sea and northern Siberia at day 10:

 

 

This could, of course, not lead to anything nationwide cold-wise in the next few weeks, but is a signal persistently showing and is a good signal long term unless the models are leading us up the garden path!

 

 

Edited December 2, 2015 by Nick F

[carinthian]

16 minutes ago, Nick F said:

 

Still the tendency by day 10 on 00z GFS and ECM ops for the Canadian ridge to have an increasing influence over the far NW Atlantic as it stretches east, though it all goes pear-shaped on GFS as it keeps low heights over Greenland. Looking at the northern hemisphere view on ECM, it suggests the trop polar vortex shifting over to Siberia/far NE Europe by day 10 and this opens the gates for poleward height rises over the N American side + there is a small rise over the pole too.

 

 

The troposphere  heights are invariably linked to the stratosphere, yesterday's ECM strat charts show the centre of the PV shifting from Greenland at t+24 towards Barents Sea and northern Siberia at day 10:

 

 

This could, of course, not lead to anything nationwide cold-wise in the next few weeks, but is a signal persistently showing and is a good signal long term unless the models are leading us up the garden path!

 

 

 

Thanks Nick, looking at what you present , I am also encouraged by developing end run of the ECM run. I hope the UKMO will be showing this at day 10. This may be our best route to something colder  for the middle of the month. Just presently amazing warmth in parts NW Europe. My daughter reported 12c  just north of Stockholm  just the other day and that at 7am in the morning and Southern Britain getting one of the mildest starts to winter ever. Warm air advection up the west coast of Greenland should enhance heights over Greenland and should help to shift the polar vortex to a location where a colder supply for most of Europe would I dare say would be welcome for most, especially us cold lovers, the hundreds of Christmas markets throughout Euroland and Blighty, we in the ski resorts and for a seasonal uplifting spirit for all. It will be a bit of a shock when it comes.

 C

[johnholmes]

Anyway the 500mb EC this morning but not GFS shows an interesting idea. IF it is correct is it the first indication of some kind of block developing way west, and possibly from the area Nick mentions, link below I hope!

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Yarmy]

37 minutes ago, -Bomber- said:

I agree the talk of Daffs in December when the ecm is showing what is showing is totally irrelevant. Didn't stop you from posting it tho. Whatever next, certainly nothing relevant 

 

It's only meant in jest though, and I thought we were all meant to be having more fun. 

Anyway, as noted above there's definitely a trend to transfer the core of the polar vortex to the Russian/Siberian side of the hemisphere. The latter frames of the ECM also has some weak polar heights, and better ridging into Canada:

 

 

[Ravelin]

It's often been difficult to find the light at the end of the tunnel in the last few days but maybe we're at least starting to find where the light switch is? As others have said, the position of the tropospheric polar vortex looks to be moving away from Greenland on the current output.

ECM at 72 & 240hrs..

But it's not just the ECM, the GFS at the same timescales shows a similar movement.

Of course the exact detail of what that brings down the line is yet to be determined, but it's got help stop the train of Atlantic lows and give us a better chance of something colder.

Just a quick point, I know it's the nirvana for 'coldies', but why is there such an apparent desperation to find 'blocking' in the models?  Even in the best of years that's a rare event, especially this early in the winter. If you're looking for snow, it's far more likely to come from a 2 or 3 day cold snap. It's worked for a lot of us north of the border already in Nov, all we need to see is it getting further south. OK, so you may not see drifts to the height of the hedgerows or snow on the ground for weeks but it'd be  a start.

Edited December 2, 2015 by Ravelin