Model Output Discussion - cold spell to end Autumn

[Derecho]

9 minutes ago, Summer Sun said:

UKMO extended at t168 has dropped the high over the UK and now introduces a northwesterly

00z

But it could be similar to the GFS at the same time, SLP over Greenland at this time has huge implications...

Edited November 27, 2017 by Quicksilver1989

[lorenzo]

Pie (albeit an anomalously warm pie) in the ECM, GEOS and GEFS sky then... not guaranteed but closer than we have come for some time..

[geordiekev]

37 minutes ago, Paul_1978 said:

 

 

Such a range of opinions and emotions!

You will get that when people are discussing different charts or times. The main trend of heights meandering around the Atlantic and UK remains which is still so much better than stormy south westerlies so nothing to worry about just yet. 

[nick sussex]

Before the NW counselling unit gets over run there is little chance of a west based neg NAO setting up because of the expected upstream pattern which is likely to force any high pressure lobe east.

The issue is timing and phasing point of shortwave energy to the sw of the UK.

And it’s  possible a lucky area could see a snow event if you can edge the pattern south,  a shortwave could run east and engage colder air to the north.

I’d be more worried if the dreaded west neg NAO was seeming the end point and as we’ve seen from the UKMO those shortwaves can cause huge changes in the outputs. From zero to hero in 12 hours !

 

Edited November 27, 2017 by nick sussex

[tight isobar]

6 minutes ago, lorenzo said:

Pie (albeit an anomalously warm pie) in the ECM, GEOS and GEFS sky then... not guaranteed but closer than we have come for some time..

Certainly some stark evidence for notable warming.

And as close as we have been in what seems a meteorlogical lifetime..

May the synoptics continue.

Canada positively scortched!

Edited November 27, 2017 by tight isobar

[winterof79]

14 minutes ago, Summer Sun said:

UKMO extended at t168 has dropped the high over the UK and now introduces a northwesterly

00z

Looks like the trough dropping down from the N/E to my untrained eye

[snowking]

2 minutes ago, lorenzo said:

Pie (albeit an anomalously warm pie) in the ECM, GEOS and GEFS sky then... not guaranteed but closer than we have come for some time..

Both the speed of the response and the level of WAFz are very impressive in day 15 modelling on both suites at the moment.

Amongst all the chaos on this side of the world, the Pacific low activity driving this has shown good continuity which continues to encourage me about our fortunes further into the season.

I have a suspicion the current eye candy on offer might just be a taster

[Timmytour]

I still thinks things look good especially for this time if year though I do understand the concerns.

If only there was a reasonable instead of apparently minute percentage of the occasional cracking looking chart verifying from 10 days out!

[Cheshire Freeze]

18 minutes ago, lorenzo said:

Pie (albeit an anomalously warm pie) in the ECM, GEOS and GEFS sky then... not guaranteed but closer than we have come for some time..

The issue is that-

a) we have no idea if an SSW will happen

b) no idea what form it will take and whether or not it will affect us positively

The issue is at the moment, if this trop-led pattern falls on its face, we have literally no other driver to bail us out and prevent the mean westerlies influencing our weather. 

I'll also add, the signal you present is most probably based on the consensus up to this point i.e overwhelming ensemble guidance of Greenland heights and associated WAA toa high latitude. If this pattern fails to manifest then prepare for those zonal wind maps to start looking very different very quickly- like last year!

Edited November 27, 2017 by CreweCold

[Ali1977]

16 minutes ago, lorenzo said:

Pie (albeit an anomalously warm pie) in the ECM, GEOS and GEFS sky then... not guaranteed but closer than we have come for some time..

Would it be late Dec/early Jan that may benefit if a SSW was to occur then? 

[booferking]

Bit of advice don't look at the Ec mean compared to last night's anyhow trend ain't are friend that's for sure.

Edited November 27, 2017 by booferking

[Summer Sun]

Clear upward trend on tonight's ECM ens from Thursday peaking at around +2 on Sunday before dropping back to around 0 until the 6th when it rises to around +2 again before another drop at the end

[lorenzo]

C'mon Crewe - enjoy the fact we have something of note to watch at present vs. staring down another nuked jet stream raging flat at us.

Ali - million dollar question there - few days to a few weeks, sometimes almost instantaneous change followed by regime changes. Met Office guide here.

Edited November 27, 2017 by lorenzo

[Summer Sun]

The ECM ens for northern Scotland also shows an upward trend peaking slightly higher than London at around +4 but unlike London, it shows another decent drop heading down to -8 at the end of its run

Yesterday 12z

Northern Scotland

Yesterday 12z London with tonight right

 

Edited November 27, 2017 by Summer Sun

[legritter]

27 minutes ago, ShortWaveHell said:

Having been a ‘watcher in the woods’ of this forum Iv decided to join today as this winter has really piqued my interest ...

its no wonder these models are having random meltdown .. wether it be short wave drama or be it background signals , this winter ,the norm isn’t taking place , the jet stream is buckled every way which , the vortex has decided to relocate , and is refusing to sleep with the trop, there’s a La Niña , the QBO is coming back from a never recorded before event  , the sun is using clearasil , and the arctic is mimicking the Bahamas ! Goodness only knows what’s around the corner but somethings definitely a stir ! But everyone on here knows ! The route to cold on these isles is of very a shaky path , but when it delivers ... it’s usually delivers  

Welcome poster ,interesting remarks and hope we see you post over the coming winter , shaky times this current model watching ,will it be mild mush in ten days time or a new high further north delivering an early snowy surprise for us snow starved Mortals , Theres always Zonal ,a bit for everyone in this part of the northern hemisphere ,cheers .

[northwestsnow]

That Ec means is a major backtrack.

Need a swing back tomorrow or i think its fair to say the northerly is in serious jeapordy..

[bobbydog]

3 hours ago, CreweCold said:

I do wonder if we are indeed following the '62-'63 template strat wise as @bobbydog has pointed out? A minor warming early December, followed by a technical SSW in January.

Obviously, even if this was to be the case, there is no saying conditions on the ground will follow a similar template.

what i find quite amazing is that this 'minor warming' which isn't particularly warm and the 'heat' doesn't really make it into the upper strat, still manages to blow the upper strat apart! if you run the sequence at the end of the 18z, its like an unseen force tears into it and even leaves an exit wound!

 

[tight isobar]

1 minute ago, northwestsnow said:

That Ec means is a major backtrack.

Need a swing back tomorrow or i think its fair to say the northerly is in serious jeapordy..

Exactly..

And highlights further why some of us eyed/noted the hints!..

And those operationals have supoort too!

Although i would'nt at-all be suprised to see a revert by tomorrow....

Wibble-wobble!!!!

[Cheshire Freeze]

1 minute ago, northwestsnow said:

That Ec means is a major backtrack.

Need a swing back tomorrow or i think its fair to say the northerly is in serious jeapordy..

And if the N'ly/Greenland blocking fails then December will be westerly (as per seasonal forecasting tools)- mark my words on that one. I would imagine the zonal winds would begin to increase fairly readily.

It's not what people want to hear I know that...

Just have to hope we can see a swing back in the ECM tomorrow...all is not lost yet.

[Met4Cast]

1 minute ago, CreweCold said:

And if the N'ly/Greenland blocking fails then December will be westerly (as per seasonal forecasting tools)- mark my words on that one. I would imagine the zonal winds would begin to increase fairly readily.

It's not what people want to hear I know that...

Just have to hope we can see a swing back in the ECM tomorrow...all is not lost yet.

Yep an entire month rests on this one, single Northerly and blocking not failing.. The atmosphere is primed for blocking at the moment with several models going for a reduction in Westerlies and a weaker than usual jet stream across the N Atlantic sector.

You can forget all of that if this one Northerly doesn't develop.

[I remember Atlantic 252]

2 minutes ago, CreweCold said:

And if the N'ly/Greenland blocking fails then December will be westerly (as per seasonal forecasting tools)- mark my words on that one. I would imagine the zonal winds would begin to increase fairly readily.

It's not what people want to hear I know that...

Just have to hope we can see a swing back in the ECM tomorrow...all is not lost yet.

December westerly, well what's new there, agree though, tomorrows runs crucial

[northwestsnow]

Ironically for me UKMO is now the best at 144- its cleaner than EC at 144-

Conclusion EC faulty.

[steveinsussex]

2 minutes ago, Daniel Smith said:

Yep an entire month rests on this one, single Northerly and blocking not failing.. The atmosphere is primed for blocking at the moment with several models going for a reduction in Westerlies and a weaker than usual jet stream across the N Atlantic sector.

You can forget all of that if this one Northerly doesn't develop.

lol

[snowking]

2 minutes ago, CreweCold said:

And if the N'ly/Greenland blocking fails then December will be westerly (as per seasonal forecasting tools)- mark my words on that one. I would imagine the zonal winds would begin to increase fairly readily.

It's not what people want to hear I know that...

Just have to hope we can see a swing back in the ECM tomorrow...all is not lost yet.

Crewe - the strat action shown at the moment is Wave 1 driven, most likely a result of the Pacific/Aleutian low forecast to set up residence in that part of the world in Week 2 - this synoptic setup drives wave flux up into the stratosphere and gives us the Wave 1 push as shown by Tony just up the page 

This has been fairly consistently modelled in recent days and remains so today. So tropospherically I agree that without the Greenland forcing we see less short term forcing on the tropospheric vortex. But in terms of interest above, I'm not so sure that we will lose the interest just yet even after the 12z suites 

[Cheshire Freeze]

Just now, Daniel Smith said:

Yep an entire month rests on this one, single Northerly and blocking not failing.. The atmosphere is primed for blocking at the moment with several models going for a reduction in Westerlies and a weaker than usual jet stream across the N Atlantic sector.

You can forget all of that if this one Northerly doesn't develop.

You clearly don't understand the nature of the atmosphere and how it works then?

It happened last year- the trop led pattern collapsed due to a failed WAA attempt at Greenland and let the upper westerlies descend with an increase in the zonal winds. So yes, it's entirely plausible that this episode could determine where we head through December. 

Remember, we're in a trop led pattern trying to hold off coupling with the upper strat until we can trigger at least some warming. As soon as the trop led pattern collapses (too soon) then you've let the mean westerlies in and the trop vortex winds itself up.