Model output discussion - The Hunt For Cold

[feb1991blizzard]

Mean rising with every run.

[Allseasons-Si]

2 minutes ago, feb1991blizzard said:

Mean rising with every run.

I think uncertainty is the word i would describe that,same from the de-built,i think shannon is paying a visit.

[feb1991blizzard]

4 minutes ago, Allseasons-si said:

I think uncertainty is the word i would describe that,same from the de-built,i think shannon is paying a visit.

It is but the mean stayed below 5c for about the last 4 days on a run a few days ago -steady rise ever since.

[blizzard81]

Extrapolating all the data from the last few days tells me one thing. All those cross polar flow runs (all gfs by the way) have all but disappeared into thin air. My own model interpretation in a nutshell. 

[feb1991blizzard]

1 minute ago, blizzard81 said:

Extrapolating all the data from the last few days tells me one thing. All those cross polar flow runs (all gfs by the way) have all but disappeared into thin air. My own model interpretation in a nutshell. 

Cant argue TBH.

[GeordieX9v]

360 on the FV3 reminds me of last weeks output from the GFS.

[Geordiesnow]

Just now, blizzard81 said:

Extrapolating all the data from the last few days tells me one thing. All those cross polar flow runs (all gfs by the way) have all but disappeared into thin air. My own model interpretation in a nutshell. 

Well of course when the GFS has the ridge extending into Greenland, we now found out this is not going to happen enough and this is where the fault of the GFS lower resolution comes into play. That said, the models are still agreeing on some form of blocking so a true cold set up can't be ruled out by any means. 

[Allseasons-Si]

3 minutes ago, feb1991blizzard said:

It is but the mean stayed below 5c for about the last 4 days on a run a few days ago -steady rise ever since.

At least the gefs ens are better than earlier(posted them on prev page)

let's not jump to conclusions and see what the next few days has in store,hopefully they will flip to cold again.

 

[Don]

7 minutes ago, feb1991blizzard said:

It is but the mean stayed below 5c for about the last 4 days on a run a few days ago -steady rise ever since.

So this upcoming cold spell may fail but hopefully after a few bites of the cherry something will come off and by that time, during winter!

[feb1991blizzard]

8 minutes ago, evans1892 said:

360 on the FV3 reminds me of last weeks output from the GFS.

on the 6z maybe.

[Catacol]

2 hours ago, lorenzo said:

 the atmosphere has moved to a new base state with higher AAM, 

Couple of composites with a few variables considering this move.. details in the subheader of variables used, tried to capture the AAM budget increase, the solar regime and the 10hPa strat regime being westerly. This for now, then if all things remained equal rolled forward, doesn't scream zonal to me

 

Yep - think I agree with this. Instead of hoping for snow drifts in mid/late November (which is a fool's errand - none of our best winters has ever featured a snowfest in November...an autumn month where latent heat is far too widespread to allow sustained wintry goodness) we should be taking a much more circumspect look at what is coming. The blocking that is on our doorstep was not difficult to see at range because of the surge in pacific sourced AAM on the back of torque increases and consequent extension of the pacific jet....and in the same way the waning of the same pattern is also foreseeable as we approach early December. However the overall background state is important as a context and I'll be very interested to see just how far the pattern wanes in early December. A higher base AAM will encourage ridges in the mid latitudes at least throughout the winter season. Low solar would appear to further impact the jet, and thereby increase the chances of ridges hitting higher latitudes. The pacific temperature profile Lorenzo has posted about would appear to strengthen Snowy Hibbos argument that we may see the MJO focus in the right phases for north atlantic blocking (though to be honest it would be difficult to argue with any certainty that this will be a season long pattern.....February is a very long way away after all) and if we get stratospheric disruption on top, encouraged by the early season strength of a high lat scandy block for example, then some very interesting weather could follow. If these dominos align then the QBO becomes less relevant in my opinion.

I'm fascinated watching things develop at the moment. Lots to be optimistic about. Widespread snow off this first upcoming cold intrusion? No - doubt it. Evolution of the drivers is the key....rather than watching some wet flakes melt on contact. Mid December ought to see the next phase of response to cyclical pacific forcing, and for me winter may start at that point if we get a decent dice roll. Don't think I'm seeing a front loaded winter however. Chances for proper cold look likely to me later on... Note too, however, that a blocky pattern can also be a mild pattern depending on where the ridges setup. That's the risk.

Edited November 18, 2018 by Catacol

[BlueHedgehog074]

2 hours ago, feb1991blizzard said:

Yes - see my post below and look at the GEFS in full and it will show you how important that low is - look at the GEFS in detail and it will show you. some members phase it with upstream troughing - either way, you dont want it just sitting there in the Atlantic.

Having had a look (using examples between 200 hours to 360 hours), certainly some interesting 18Z GEFS solutions on offer above. Various ideas as to how the Atlantic Low Pressure handled. Some with it just blowing up in the Atlantic and getting stuck in that area, with ridging pumped up over Eastern UK. Some cutting the Low through East and North-Eastwards over, or to the North-West of, the UK forcing more of a Western based negative NAO pattern to develop for a time on a few (though also a few that have the Low Pressure clearing or dropping to the East or South-East of U.K. with High Pressure re-inforced to our North-West or in the mid Atlantic). Some as well where Low Pressure does continue to slide under some Greenland/Iceland/Northern UK blocking. Particularly on the ones where blocking is particularly strong to our North-West maintaining that Southerly tracking Jet and the Low(s) to the South of the block being fairly weak. Probably one of the ideal scenarios to have for continued cold combined with Scandinavian troughing. 

Additionally, a few odd ones where Low Pressure seems to be held in the Western Atlantic/Newfoundland area throwing some warmer air up towards Greenland - blocking maintained to our West/North-West in the Atlantic or Greenland area and Low Pressure dropping down to the East from Scandinavia with chilly Northerly or North-Easterly flows over the U.K. 

High Pressure does stay close by or over the U.K on some of the above 18Z GEFS examples. And what does seem evident is hardly any strong, flat, Westerly, Atlantic drivern weather on many. So I guess even if a break from the colder weather happens this week, seeing a beastly Vortex dominating to our North-West with a flat Jet powering through us is perhaps unlikely. At least according to these ensembles anyway and as longs, I guess, continued battering of the Polar Vortex arises.

Wasn’t intending to ramble on like this and some of the above ensembles I may have observed inaccurately , but just getting a better idea of what needs to be looked out for if wanting cold and blocked patterns to continue.  

(Must get to bed now lol. May you all sleep well )

 

Edited November 18, 2018 by DiagonalRedLine

[jules216]

7 hours ago, Don said:

Why do you think this will stick around for winter?

This is not backed by any scientific reasoning,as there is a lack of of research done on central/eastern Europe high,but my reasonings are:

1. It has been the signature pattern for most of the last 6 winters,except for month after SSW in 2018,2013,partially Jan 17 and very early Dec 17,although @Catacol seems to disagree with me on this one.

2. Most of the winter forecasts I've read recently have  an active STJ leaving eastern CONUS-signature of this type of EL Nino. That makes us suspect to a cut of low pressure areas south of Ireland, pumping high pressure to central EU if they don't manage to undercut properly, see attached image of most recent GFS run,which despite plenty of blocking produce very little cold. The through that could potentially dive south from Scandi that can bring cold loses the battle against the advecting central/eastern EU high. These synoptics  nicely match west based -NAO.

3. No Atlantic tripole - cold SST west of Ireland- since these SST cooled so much in past years they have promoted low pressure areas much more that blocking highs - the lack of proper east based - NAO.

4. Only my opinion,but I believe we will be yet again waiting for a stratospheric event to bring sustained cold pattern in Europe back end of winter

[Seasonality]

So if this GFS para really is verifying better than its older brother then surely we should give it credence. Comparisons here in the mid term. Really quite important differences leading to rather colder outcomes. 

[That ECM]

It’s after this point t120-t144 where ecm and gfs differ greatly. Ecm has the high going a little further nw gfs has it moving se. Further down each run you can see how this would affect us. For what it’s worth imo the ukmo would follow the ecm route. Chances of a northerly have increased for me this morning.

Edited November 18, 2018 by That ECM

[swfc]

Morning.id agree with that ECM so far today things don't look that bad tbh!! Ukmo and ECM look to be on the Same hymn sheet imo.ecm 850s look pretty good to the north of the UK at day 10.Idont or never did see a winter wonderland but any blocking towards Iceland ete can't be a bad thing given its november.people are looking at forcasts that haven't even happened yet and changes will come over even the next few days maybe for the good or bad given your preference.The current patterns don't scream raging zonality so all to play for heading towards winter imo.just as a side note Tamara's comments the other day do look to have some credence ATM .

Edited November 18, 2018 by swfc

[BLAST FROM THE PAST]

ECM, GFS(p), GEM, UKMO......all looking good, and pull away from the sinker....I’m surprised it’s so quiet

 

BFTP

[JeffC]

5 minutes ago, BLAST FROM THE PAST said:

ECM, GFS(p), GEM, UKMO......all looking good, and pull away from the sinker....I’m surprised it’s so quiet

 

BFTP

The morning after the night before? 

[SLEETY]

chance of even colder weather from the North that the METO mentions,has increased after the overnight runs.

Exciting times ahead.

[Tim Bland]

Synoptics wise the models look ok (apart from GFS) but they fail to deliver cold and snow which is what most want. I guess we are back to looking for potential and now looking towards the second week of December onwards for cold and snow. 

[northwestsnow]

Well i'm still on the fence,last couple of EC dets have improved from a coldies POV but there is so much energy distribution for the models to handle post 144 that making a guess how it will all unfold for the UK is nion impossible imho.

One thing looks fairly certain and that is central/east Europe looks set to go cold..

Think we will see a number of scenarios play out over the coming 48 hours..

Edited November 18, 2018 by northwestsnow

[Met4Cast]

GFS still sinking the high into the continent, ECM mean looks decent enough

Though day 10 doesn't look great, but plenty of time for that to be resolved

UKMO/FV3 looking good too. It's pointless looking beyond about 168hrs, anything shown past there will likely be completely wrong, it's the short-medium term we're likely to see the upgrades in, as we have seen overnight.

[northwestsnow]

UKMO 144 again looks the pick of the big 3 for me..

 

 

[SMU]

Superb outlook now - Scandi High - chance of snow, then retrograde to iceland with a reload from the NE - 

Finally ECM churning out the kind of charts that the UKMO would have done if it had run past 144-

Cant really see how anyone can be critical this morning when we normally are ramping up the zonal westerlies now!

[shaky]

1 minute ago, Steve Murr said:

Superb outlook now - Scandi High - chance of snow, then retrograde to iceland with a reload from the NE - 

Finally ECM churning out the kind of charts that the UKMO would have done if it had run past 144-

Cant really see how anyone can be critical this morning when we normally are ramping up the zonal westerlies now!

In the short term you still think chance of snow across the east and south east from the easterly?!ecm shows -6 and -7 uppers as the ber minimum!!ukmo around same i think!