Stratosphere Temperature Watch 2014/2015

[sebastiaan1973]

Well Cohen forecast for this winter is no suprise. He expects in large parts of NH cold weather. http://www.nsf.gov/news/special_reports/autumnwinter/predicts.jsp

 

.

Edited November 22, 2014 by sebastiaan1973

[lorenzo]

Cracking split vortex shown on the 06z GFS, only caveat being..... it's the 06z GFS !

 

Whilst a second wave 2 hit is projected always correct to be wary where this model, and this run in particular, was pre-disposed to continual stratospheric blowtorches last season. No real cause for concern, just at that range it really is trends versus anything reliable, even the ECM Berlin plots are prone to lifting waves beyond day 6/7 above the verified amplitude.

 

Worth plotting up the preferred split again for reference, taken from Ed's original from mod thread last week with some splashes of colour thrown in. Preferred split visible in yellow.

 

[neige57]

Cracking split vortex shown on the 06z GFS, only caveat being..... it's the 06z GFS !

 

Whilst a second wave 2 hit is projected always correct to be wary where this model, and this run in particular, was pre-disposed to continual stratospheric blowtorches last season. No real cause for concern, just at that range it really is trends versus anything reliable, even the ECM Berlin plots are prone to lifting waves beyond day 6/7 above the verified amplitude.

 

Worth plotting up the preferred split again for reference, taken from Ed's original from mod thread last week with some splashes of colour thrown in. Preferred split visible in yellow.

 

gfs_t30mb_globe_65 (2).png

 

With a strong QBO- on several levels, it could all go very fast, can be faster than that suggested the current stratospheric models. I just signal that will reach the peak QBO- in the heart of winter combined with a weak El Nino. The QBO- will be around -25 during December and January, with a peak at the end of the year. A figure as low in the heart of winter was no longer produced since December 2005 closely followed by December 1965 and that's all

[snowking]

Still liking the look of this:

 

Poleward flux will certainly help break in to the surf zone if the warmings right at the top do indeed downwell. Speaking of which:

 

 

At 16c, it's likely to be warmer up there than it will be at the surface here next week.

 

The only concern at the present moment is the forecast location of the split vortices, but when we bear in mind the very early stage of the season we are at right now there is plenty of time for these to be shifted around pretty extensively within the very inhospitable vortex environment at present in the stratosphere.

 

I would imagine the mood across these forums will be very different indeed in around a months time.

 

SK

[NorthernRab]

Well Cohen forecast for this winter is no suprise. He expects in large parts of NH cold weather. http://www.nsf.gov/news/special_reports/autumnwinter/predicts.jsp

 

.

Great forecast, but I hope he's very wrong about Scotland!

[chionomaniac]

It could be a simple answer to this, they might actually be a bit too busy to post at the moment.

From chionomaniac on Twitter

"Starting winter with u wind under 40m/s and warming projected at 1hPA - Any cold lover will take that! pic.twitter.com/CBeD9iSua3

That's the reason!

Edited November 22, 2014 by chionomaniac

[Cloud 10]

Cracking split vortex shown on the 06z GFS, only caveat being..... it's the 06z GFS !

 

Whilst a second wave 2 hit is projected always correct to be wary where this model, and this run in particular, was pre-disposed to continual stratospheric blowtorches last season. No real cause for concern, just at that range it really is trends versus anything reliable, even the ECM Berlin plots are prone to lifting waves beyond day 6/7 above the verified amplitude.

 

Worth plotting up the preferred split again for reference, taken from Ed's original from mod thread last week with some splashes of colour thrown in. Preferred split visible in yellow.

 

gfs_t30mb_globe_65 (2).png

 

Its okay,the "split" is still there on the gfs 12z so is now guaranteed to happen precisely as shown without any deviation.

 

[karyo]

After the good 6z, both the 12z and the 18z have downgraded the early December warming and the split.

[Recretos]

I am quite busy in the last days, and I am not even at home, so I cant make any plots for you. But I called home and I gave my sister a crash course in modelling and plotting and she made a graphic, tho not as perfect, but still, the main thing is visible.

This is 384h forecast of the para GFS, from 23.11 00z. its the 10mb GPH.

[MattH]

Morning...

 

Just a quick one but the vortex really is just waiting to be 'knocked out' here now...

 

 

The EPV flux forecast continues to look good as well and whilst the ECM shows a potential reduction in wave 1 activity, wave 2 activity is forecast to increase towards the end of the period and in what looks to be quite a central and favourable location within the stratosphere.

 

So, still no changes from me. Trop charts still highlighting the PV over Greenland area with a more zonal look to things, but still expecting a sig change mid to late December, perhaps even early with what could be a very interesting festive period this year in terms of synoptics.

 

Just a matter of time, if you ask me, that the flailing strat vortex is 'taken down'...

 

Matt.

[feb1991blizzard]

Morning...

 

Just a quick one but the vortex really is just waiting to be 'knocked out' here now...

 

 

The EPV flux forecast continues to look good as well and whilst the ECM shows a potential reduction in wave 1 activity, wave 2 activity is forecast to increase towards the end of the period and in what looks to be quite a central and favourable location within the stratosphere.

 

So, still no changes from me. Trop charts still highlighting the PV over Greenland area with a more zonal look to things, but still expecting a sig change mid to late December, perhaps even early with what could be a very interesting festive period this year in terms of synoptics.

 

Just a matter of time, if you ask me, that the flailing strat vortex is 'taken down'...

 

Matt.

 

Yes, even if we didn't have access to strat charts, you can see the sharp ridges slicing the polar vortex open via Scandinavia, it will only be a matter of time before enough cold uppers are in Europe and the Atlantic troughing ejects a trigger shortwave south to advect them this way, Jan 1987 springs to mind.

[Duane S.]

This caught my eye this morning

Not withstanding it is only fairly moderate in nature, it is of interest. Here we have the mid Strat now coming under increasing pressure. The top continues to be all over the place and in no position to recover properly for the foreseeable. If (and I think it looks likely) we get a big wave2 break early - mid December, there will be little (relative) resistance and the vortex is going to be (again, relatively speaking) blown apart and cold will flood out down into the mid latitudes not too long afterwards.

It has been more of a slow burner than I had originally hoped back in mid October but that was more than tinged with a healthy portion of optimism I suspect! So, The last half/third of December into the New Year looks like it is going to be where it's at. GEFS haven't sniffed anything yet out in FI, my guess is when it happens it will likely happen fairly suddenly, the -10 runs will appear (seemingly) out of nowhere and their occurrences will increase (with usual blips of course!).

[sebastiaan1973]

The conditions under which a SSW event is more likely to effectively propagate into the troposphere and perturb the 500mb pattern are winters with a backdrop of -QBO / low solar activity, or +QBO / high solar activity (solar will be addressed in the next section). The overall environment is more favorable than normal for effective downward propagation this cold season due to the presence of an easterly QBO signal and generally decreased solar activity in comparison to the past few winters. Negative (positive) QBO episodes induce increased easterly (westerly) wind anomalies in the upper stratosphere, creating a more (less) favorable pattern for potential sudden stratospheric warming events. Therefore, a negative QBO in and of itself is the preferred state for enhanced stratospheric warming, which can often yield a negative AO in the troposphere. A negative QBO is in fact present right now (strongly negative in fact). www.americanwx.com/bb/index.php/topic/44944-my-winter-outlook-2014-15/#entry3138966
 

[feb1991blizzard]

These charts are surely going to help down the line.

 

 

 

 

[ITSY]

Yes I'm no expert on this, but the GFSP seems to ramp up the warming and possible split of the vortex up in the strat. Certainly no SSW to my eye (my basic knowledge would suggest that the temp doesn't rise enough and the vortex never entirely displaced), but a definite split with at least 2 waves of warming at the strat level. The GEM also presents another version of it's earlier attempt at our level, so some signs to think about I would think. Best to wait for the experts to give their view, but more optimistic after that run

[snowking]

Always worth viewing the charts with some geopotential heights attached:

 

 

Very promising in terms of keeping the vortex weak overall - still not the killer blow, but with the vortex in such a state of disarray you feel it is only a matter of time before we see such a scenario...

 

Of course it's also worth bearing in mind this is a single operational run at quite some way out, but it does tend to tie in with the limited shots of the ECM mean at this range from WSI

 

SK

[LomondSnowstorm]

Looks like a decent split at the 30mb level as well on the parallel by the end of the run, temperatures at the pole over -50C which is pretty impressive for this early in the season:

edit: SK beat me to it!

[feb1991blizzard]

Always worth viewing the charts with some geopotential heights attached:

 

 

Very promising in terms of keeping the vortex weak overall - still not the killer blow, but with the vortex in such a state of disarray you feel it is only a matter of time before we see such a scenario...

 

Of course it's also worth bearing in mind this is a single operational run at quite some way out, but it does tend to tie in with the limited shots of the ECM mean at this range from WSI

 

SK

 

Yes I wished meteociel had the overlay, I still think we need the Western lobe segment needs to be even further away though.

[Snowy L]

Always worth viewing the charts with some geopotential heights attached:

 

 

Very promising in terms of keeping the vortex weak overall - still not the killer blow, but with the vortex in such a state of disarray you feel it is only a matter of time before we see such a scenario...

 

Of course it's also worth bearing in mind this is a single operational run at quite some way out, but it does tend to tie in with the limited shots of the ECM mean at this range from WSI

 

SK

Really unfortunate placement of the Greenland lobe though, need  further wave breaking originating in the North Atlantic.

[Snowman.]

Really unfortunate placement of the Greenland lobe though, need  further wave breaking originating in the North Atlantic.

 

There's been a fair few runs keeping vortex as one but over by Siberia.

[aginob]

hi guys

Metcheck have a new Layout and a new Parameter

Stratosphere Forecasts ... Northern and Southern Hemisphere

http://www.metcheck.com/SEASONAL/stratosphere_forecasts.asp

http://www.metcheck.com/UK ... http://www.metcheck.com/UK/home.asp

Edited November 23, 2014 by aginob

[neige57]

ECMWF confirms the great potential this evening with a huge pressure on the Polar Vortex

 

 

 

 

 

Even better on the JMA 120h deadline

 

 

Edited November 23, 2014 by neige57

[MattH]

Morning...

 

There's some consolidation of the strat this morning within yesterday's ECMWF after a split, of sorts, at the 30hPa level for example. However, that still doesn't take anything away from the overal setup which, as ever, is highlighted well on the below images; 

 

The wave 1 activity is still forecast to gradually deline in intensity, but it still remains a feature at the top of the stratosphere, so not a bad thing and wave 2 activity is still forecast to develop, but without getting too significant. Just as with the last few weeks it remains a waiting game for a more significant spell, in my opinion, of wave 2 activity now. We've seen what sustained wave 1 activity has done to the strat vortex early in the season, but clearly to really get things going in terms of splitting the vortex and getting anywhere near to a SSW then we need some decent wave 2 activity. It's fine having some 'heat' at the top of the strat, but we need to get some warming from the bottom up in my opinion. It's almost at that point now where focus may well need to be on the troposphere rather than the stratosphere to see if we can get any 'help' from the broader synoptic patterns across the N Hem in terms of possible MT events and the likes, as whilst clearly in a weakened state it's still going to take some time (weeks I believe) until we get anywhere near to the 'holy grail' scenario of a SSW and what may well follow.

 

Clearly the medium and long range output is very uncertain and there are some interesting synoptics developing ( http://www.wetterzentrale.de/pics/Rtavn2401.gif ) in terms of higher pressure becoming more dominant now rather than the Atlantic being 'allowed in' despite quite a strong PV setting up shop over Greenland. Personally I would sooner have the more settled conditions, even if not that cold, rather than wet and windy weather. Fog and frost compared with wind and rain I'll take anyday at this time of year. Obviously that's for a different thread, but coming back to the strat and it's a case of 'onwards and upwards' but it's going to take time, but hopefully within the next 2 to 4 weeks, from somewhere we'll see a major increase in wave 2 activity in particular to really get things going. Still no change from me, December will progress in a fashion that will resemble nothing like last December and high pressure will never be too far away, but I still believe it'll be over Christmas into the New Year when things could get 'interesting' but we'll see...

 

Cheers, Matt.

[karyo]

The last few GFS runs are showing an intensifying vortex for early December. The secondary warming that was showing up to a couple of days ago seems to have vanished at least from the 30hpa level.

 

Karyo

[neige57]

The last few GFS runs are showing an intensifying vortex for early December. The secondary warming that was showing up to a couple of days ago seems to have vanished at least from the 30hpa level.

 

Karyo

 

you speak of détermiste GFS? because the GFS // this is another story and very different. Do not look at the GFS détermiste soon to be replaced