Q is probably about 20.

The current outputs are guff.

SSW annoys everyone. 

It's not mild it's average and so much better than last year. 

Tallyho has seen definitive signs of a pattern change at T+A year

And it will probably be April before this makes 50 pages. 

Usual rules apply 

Hmmm I'm sure Pembo would agree 😉 I reckon Q is 24. 

But there was a reason for my question. Anyway back on topic...

What was the reason for your question?

Is there any chance we could comment about model output and not Q's age?

This is personal stuff bordering on trolling

going back to the previous thread, the question was asked as to why the SSW hasnt begun to show in the charts yet and then other posts that it will take several weeks for anything to show.

there is no straight answer but

there is currently no SSW forecast. there is a strong warming which splits the upper vortex (cue the arctic high appearing) but the modelling is then unclear as to how well the vortex reforms or then resplits or is displaced.  there may well be a SSW within two weeks. there may not. there should be a response from the trop to these warmings anyway.  given the upcoming strong zonal pattern in our part of the hemisphere, i suspect it will take a full on reversal to change our fortunes, other than introducing some amplifocation to bring some pm shots or a build of arctic heights to sink the jet and pull us under the cold upper trough.

sometimes, it can take several weeks for a reversal to propogate down to the trop but at the moment, the trop/ mid strat appears to be well coupled and the upper strat is downwelling fairly effectively into the mid strat with a few days delay. 

my overall view is that at the moment, the strat is not driving events in the trop. infact. it could be argued that it is the other way around. the environment in the mid strat is very benign and will allow whatever trop driver that is taking the lead to continue to do so. only a very big split and warming or complete reversal can be expected to override the trop upper pattern of zonality for our side of the NH. 

My age is probably one of the most interesting things to discuss at the moment 

Hope of EPS being slightly better is dashed. This is a returning polar airmass, which means while it might be below avg in the NW, it is mundane for the rest of us, and probably quite wet. Same show as last year really. All I can hope is that we get some ice forming down the E coast soon to slow the cyclogenesis. Didn't work last year ofc and there was plenty of ice then.

Apologies - that's wasn't my intention - it was purely lighthearted, however consider the matter closed. 

I shall revert back to mute observation of the thread.

He's right. We have electric daveyworld for that 

I wonder if peeps in the usual flood prone areas are getting twitchy. 

LOL Matty - glad you got the name wrong........anyway rainfall could become an issue if we start to see secondary lows in the mix

To be clear, I was never offended by the question people! No one needs to be apologising! If I was the type to be easily offended I wouldn't spend so much time in the climate forum 

Prepare the reading glasses, it's a big one I'm afraid 

Not much worth saying about the trop. output from the models within the reliable, while beyond that there are hints that the main focus of low heights might shift SE toward the UK from GFS and GFSP but these are contradicted by the ECM run which wants to break only part of the low heights away from the NW, slide that quickly SE and then start building a ridge over us instead.

Meanwhile, the stratosphere output continues to show significant events, with the warming over Greenland gaining further ground on GFSP which has upgraded it a lot over the past couple of days. Meanwhile ECM has toned it down just a little and is no longer the most aggressive solution, that trophy going to NAVGEM which raises the 10hPa temperature all the way up to 0*C, which is quite extreme really. JMA is consistent with its previous two runs.

Highlights:

The GFSP solution (left) now has the warming starting at a high enough latitude (between NE Canada and Greenland as can be seen here: http://modeles.meteociel.fr/modeles/gfsp/runs/2014123012/gfsnh-10-192.png?12) to bring about a second, larger split only a few days after the first (occuring days 7-8) has closed off.

What's not clear from the above is whether the actual 10mb troughs are fully split or not, but with the low temperatures set so far apart it seems likely.

The JMA solution (right) takes the core of the warming 8*C higher than GFSP, and it's even better placed to take down the Canadian vortex - hard to see a way back for it any times soon if that comes off.

This is quite similar to what I've read about the strat. output from the 12z ECM op run, which also takes down the Canadian vortex. In terms of the actual troughs, the day 10 chart features a weak Siberian vortex and a trough extension (like a narrow branch) toward Canada. At that point we will need further wave 2 action to split that weak remnant of the Canadian trough from the dominant Siberian one days 11-14, producing results similar to the GFSP chart above.

So it seems that ECM and GFSP are closing in on a point somewhere between their original output... but of course it's GFS that has done by far the most adjustment these past few days.

As far as getting the all-important split goes, it's very encouraging output this evening. 

The man behind the Cohen strat. theory (yes, Cohen himself) concurs:

"Based on the ECMWF forecast, the SSW will get close to a major SSW (defined as a zonal mean easterly wind at 10 hPa and 60°N) and would likely achieve major SSW strength with further wave driving.  The GFS has displayed a bias all winter of under-predicting the vertical WAFz and over-predicting polar vortex strength.  Therefore we favor the ECMWF forecast of a more perturbed and longer duration polar vortex weakening."

Just to complicate matters further we see that there are Sudden Stratospheric Warmings (SSW) and then major ones (major SSW). The latter is the one with the zonal wind reversal, the former falls short of that. It makes sense really, as the warming is large and does happen very quickly on recent model output, yet a zonal wind reversal remains just beyond the output of ECMWF, for example.

By way of balance to the above post, Cohen also covers what has been a troublesome feature so far this winter and the primary reason for the December warming being unable to bring about a SSW:

"longer-term prospects for the AO continue to hinge on the anomalous polar low in the Barents Kara-seas region that has temporarily weakened. It is predicted to strengthen again across the north slope of Siberia and eventually move back over the Barents Kara seas region. Perhaps the current temporary relaxation is a foreshadowing of a longer term weakening trend but for as long as the Barents-Kara seas low persists, it destructively interferes with an externally forced negative AO (from the SSW). The biggest impact would to inhibit the flow of Siberian air into Europe. It’s impact would be less on North American temperatures where in the near term, ridging across western North America and a polar low in eastern Canada will direct arctic air into the lower 48."

"It is hard to predict how long this area of low pressure will persist, which is likely to be at least somewhat supported by the relatively extensive North Atlantic sea ice extent compared to recent years and to the North Pacific side of the Arctic. As long as low pressure remains near the Barents-Kara seas any tropospheric influences from the stratosphere this time period will be favored across North America relative to Europe. However if a piece of the polar low can move over Europe then this could help force much colder weather into Europe".

This looks like a good example of the sort of thing that prevents a SSW from being a guaranteed route to cold conditions across the UK or even NW Europe. There are always complications!

Ironically, having a low over the Barents-Kara Seas (just north of Scandinavia) is actually a pretty cold setup for us (but not necessarily NW Europe) if there is decent mid-Atlantic ridging, and this is a possibility prior to any SSW driven changes if the Canadian vortex is shut down. Recent GFSP runs have hinted at such things despite never fully taking apart that vortex. GFS is still not with it as far as the strat. output is concerned so the day 10-16 trop. output is a poor guide, and GEFS even worse (these, I have been told, do not model the whole of the stratosphere. Feel free to correct me again if this is not true, Brian.)

I must stress that Atlantic ridge/Scandi trough possibility requires the ECM/JMA strat. output to be close to the mark, and applies to week 3 to 4 of January. There remains little reason to expect much of a downward trend - or indeed any at all - in temperatures in the first half of the month.

The current GEFS top is 2hPa and datasets include 10,20,30,50,70,100, 150...etc

The upgraded GEFS which is scheduled for next year will have a top of 0.2hPa and 64 vertical levels. The runs will be time stepped at 3 hour intervals (instead of the current 6) and be available in 0.5x0.5 deg datasets in addition to the current 1 deg and 2.5 deg datasets. 

Brian, how would I go about downloading 1hpa charts for the GFS?

http://www.meteociel.fr/modeles/archives/archives.php

@ Matty What's confusing for some is you get the odd person who has no idea what they are on about, saying SSW has been taking place, or about to take place, since early November.

As was discussed earlier, too much faith is placed in this as a solitary factor by some, even more so by the odd one or two that don't understand it, and it's no one that's posted in here recently. I don't understand it's affects either.

I hope this wasn't directed at me as I never stated a SSW back in November and merely reported on the NH profile looking good going forward. 

Nope, not you. 

Lets be honest, most of the predictions on this forum (and others) during the winter months wouldn't be realised in Alaska, let alone in one of the mildest countries at 50 north on the globe which the UK is. 

Calm down, don't have a hissy fit...it's only the weather 

And back to about the models.

It is me or there seems to be a little bit more in the way of ridging in from the south. If so, that would have the effect of pushing all the nasty annoying in-your-face lows that little bit further north. The models seems to be singing from the same sheet to 180 hours - and even beyond.
  Like I said, if we are not going to have the perfect synoptic to deliver proper cold and snow, at least keep it all nice and relaxed with useful conditions for gardeners and agriculture workers.

The MO  medium  range seems to  suggest  the south and east getting a fair bit of drier stuff.  I agree, if we can't have  decent cold and snow, may as well have some  usable weather -  Never know, could  see a return of "Uncle  Barty"   (I'll get my coat) 

Is this classified as a Bart?