Stratosphere Temperature Watch 2012/2013

[SMU]

The vortex being smashed to peices will have a very high statistical correlation ( poss near 1) with a negative AO-

however whats not clear is where we would get a 3 or 4 wave pattern-

Scandi seems to fit the bill initially as one of the waves, however greenland will be more longterm idea.

S

[phil nw.]

The reduction in the zonal winds is apparent in the latest forecasts with a reversal showing at high latitudes.

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/eczm.php?alert=1&forecast=all&var=u&lng=eng

weakness in the mean winds showing higher up now following the recent wave breaking-reflecting the punch drunk vortex.

[chionomaniac]

I thought that they were 100 hPa charts tthat you had put up! But looking closer I see they are 30 Hpa charts. Now that is really something and the best of the season yet!

[Glacier Point]

Yes, makes it all the more impressive doesn't it ?

I would go for 3 wave for December, morphing 4 wave when we get the Greeny.

If I get time, might be able to post up the 30 hPa zonal wind comparison with 1968. I reckon we are running about a 3 days behind the pattern of that year. And of corse, AO value for that winter ???!

Edited November 30, 2012 by Glacier Point

[SMU]

1968 morphing to 1978!

[chionomaniac]

Yes, makes it all the more impressive doesn't it ?

I would go for 3 wave for December, morphing 4 wave when we get the Greeny.

If I get time, might be able to post up the 30 hPa zonal wind comparison with 1968. I reckon we are running about a 3 days behind the pattern of that year. And of corse, AO value for that winter ???!

And did I here a rumour that we may be heading back to a weak El Nino as well with a projected westerly wind burst- or was that all it was?

[sebastiaan1973]

Yes, makes it all the more impressive doesn't it ?

I would go for 3 wave for December, morphing 4 wave when we get the Greeny.

If I get time, might be able to post up the 30 hPa zonal wind comparison with 1968. I reckon we are running about a 3 days behind the pattern of that year. And of corse, AO value for that winter ???!

Funny, I came along this post from the American Board. Perhaps it's coincidence, he referts to 1968. http://www.americanwx.com/bb/index.php/topic/34743-winter-2012-2013/page__st__3255#entry1889194

[chionomaniac]

Funny, I came along this post from the American Board. Perhaps it's coincidence, he referts to 1968. http://www.americanw...55#entry1889194

I remember looking at previous comparable years in the winter thread earlier in the autumn and 1968/69 came out on top then alongside (cough) 1962/3. But those analogues were based on a more convincing ( that would be weak) el nino phase - which is why I mentioned it above.

[snowking]

I know SLP pattern matching is hardly the pinnacle of science, but I have discussed through the autumn on other forums the remarkable synoptic similarities between apr-sep 1962 and 2012

I don't think we would be looking at anywhere near the depth of cold as then, but the longevity? Might not be too far away.

All mere speculation but given the repeated forecast hits on the stratospheric vortex (which, IMO, despite the disconnect has been the only factor preventing a major cool down even through the autumn) I'm more optimistic of such discussions not being far off the mark

SK

[Catacol]

I'm still a real climate/weather novice after years and years of lurking, though starting to feel knowledgeable enough these days now to post. However I'm definitely a strat baby. However I asked a day or so ago as to whether there has been another year where the strat breaks into 4 or indeed has been as split as it is currently. I've skimmed some more charts for a while just now - not found anything that resembles our current situation nor my mental image of the quadruple split that GP alludes to.

Anyone know of a past analog or chart where the vortex was so badly wrecked?

[chionomaniac]

This is more a tropospheric based chart than stratospheric. The disturbance of the stratospheric vortex will lead to the 4 wave troposperic pattern.

And of course we don't have to look too far back to find one - two years ago to be precise.

Edited November 30, 2012 by chionomaniac

[chiller]

Hi folks - forgive my ignorance but did 68/69 turn out to be rather harsh for the UK?

[Bradowl]

Hi folks - forgive my ignorance but did 68/69 turn out to be rather harsh for the UK?

Yes it was and this is the first winter I remember because I was only 4 at time.

I remember overflow pipe freezing over outside resulting in water tank overflowing and flooding house.

Also built my first Snowman. :-)

[SouthPennine88]

Yes it was and this is the first winter I remember because I was only 4 at time.

I remember overflow pipe freezing over outside resulting in water tank overflowing and flooding house.

Also built my first Snowman. :-)

I understand this is heading slightly off topic, but I believe 68/69 was also the subject of when the Emley Moor TV mast in Yorkshire collapsed due to a mass build up of ice on it.

[Catacol]

This is more a tropospheric based chart than stratospheric. The disturbance of the stratospheric vortex will lead to the 4 wave troposperic pattern.

And of course we don't have to look too far back to find one - two years ago to be precise.

Well blow me down - now I feel stupid. Only 2 years ago. I did scan 2010 but not in and around the 18th.

How common are these sorts of charts?

[virtualsphere]

Hi folks - forgive my ignorance but did 68/69 turn out to be rather harsh for the UK?

Apologies if this is off-topic, but in reply I had a quick look at 1968-9 in this post. It wasn't specifically related to the stratosphere which is why I posted it in the general winter thread but it has probably got a bit buried now.

[Recretos]

I see people mentioning 68/69. I thought I could add some reanalysis charts for a better idea of that period (even tho I think most of you already play around with reanalysis tools). Lets keep in mind that regarding reanalysis data, 68/69 is before the satellite era, but I do believe the datasets are as accurate as they can be.

In that period we were in a cold PDO/cold AMO setup, and going from negative biased neutral ENSO3.4 (basically in La Nina values but not long enough to be classified as a La Nina) in the first part of the year to a weak El Nino by the end of the year. Also worth pointing out, is the negative QBO going into winter. Adding the late November 2012 QBo for comparison.

The winter pattern composite. This is basically very similar to my statistical winter outlook, and also one of my analog years.

This is the pattern comparison between second half of November in 68 and 12. Basically not so similar, except for EU, E Atlantic and Asia. Also more ridging present over Atlantic this year, more than likely linked with the warm AMO. And the AO/NAO comparison.

The late November comparison.

Now the stratosphere reanalysis is interesting, showing a nice little displacement already in late November. I wouldn't really rely on the pre-80's strat analyses, but i guess its as close as it gets.

Each month of 1968 winter.

And last, the pre-November 500mb pattern comparisons and QBO.

ECMWF vs GFS (12z run)

http://shrani.si/f/1Z/RH/3oXv1GXV/test8.gif

CFSv2 week 1 & 2

http://shrani.si/f/J/8T/1EoTsalT/wk1wk220121129z500.gif

BCC Monthly forecast.

http://shrani.si/f/3a/yu/yBk97by/md2012116nhh5m11.gif

Best Regards.

Edit: Added Nov. 2012 QBO, 12z ECMWF vs. GFS and CFS and BCC forecast.

Edited November 30, 2012 by Recretos

[bluearmy]

The latter stages of the updated ecm data shows zonal winds in the mid strat restrengthening after they drop off over the next week. Although not recovering far above 20m/s at 30 hpa, i was rather hoping we wouldnt see this although the forecast redrop in temps at 30hpa is probably responsible for the upsurge.

Wave 1 activity isnt forecast to downwell too far, though its strong in the upper strat. Wave 2 activity drops off through the run and we await signs of it returning to prevent any overstrengthening of those mid strat zonal winds. although last time, there was no propogation of these winds down into the trop, are we certain we would have the same result if the pattern repeated?

[chionomaniac]

Well, time for an update - and what an exciting one to bring you!

Let's start with the stratosphere as it is today.

We have seen the polar vortex split by an increase in wave 2 activity - this has led to two daughter vortices - one situated over Siberia and the other situated over Canada as shown below on the ECM 100 hPa chart (low strat):

The voretex will eventually reform back into one displaced unit and it has been this reformation that has troubled the model output over the last week. however, we are starting to see signs that the vortex is more likely to be displaced towards the Canadian segment with energy transferring back across Greenland during the reformation process. Both the ECM and GFS show similar stories by day 10 - the main vortex displaced towards Canada and NW Greenland but with an elongation and stretching of the euro trough towards Africa.

This will intially prevent heights extending too far north into Greenland whilst allowing weak heights to build into the extended euro trough (Scandi area). It is likely that any troughs crossing the Atlantic may get cut off from the main flow up to day 10.

So, next the best bit of the forecast - the EP flux is forecast to be directed poleward! A rare projection during winters normally seen in SSW's.

This is forecast around days 8-9 and the likely effect is to send the polar vortex to the shredder. How it shreds the vortex we do not know yet, but we shall see many fantastic ouputs over the coming days if this is maintained - we are likely to see some great output post T+240 that hopefully will be reeled in if that flux forecast remains. Here is one such scenario from the latest 6Z GFS run -

Great Greenland height rises there!

For me winter a proper is coming and I suspect that we will see well below average temperatures around the middle of the month!

Fingers crossed and we still may have a warming to come later on in winter as well!

Edited December 1, 2012 by chionomaniac

[bluearmy]

good spot ed re the ep flux. seems a long way off so we need to hope it repeats on the upcoming forecasts. i do worry when you talk about the vortex being shredded as we so often get the chunks in the wrong place for us as we are currently seeing. a straight split generally delivers for our part of the hemisphere. anyway, a good position to be in to start winter proper. i recall that in dec '10, it wasnt more than a week or so into the month that stewart posted that the strengthening of the strat vortex promised an end to the cold for jan. here we are with a neg cet first half of the month to come and chances for snow and we are looking for upgrades in the strat forecast from a more than decent base position!!

fwiw, i agree re mid month and expect a solution akin to dec'09 to materialise.

[geoffw]

chino, have you produced a winter forecast, it would be a pleasure to read

[chionomaniac]

chino, have you produced a winter forecast, it would be a pleasure to read

Sadly no - I am not that skilled! But thanks Geoff - perhaps one day.

[MattH]

Great summary and analysis C...

Must admit I often look through the full ECMWF suite in the morning to check for anything of interest and most certainly missed that EP Flux signal this morning myself. As you mention, given the importance and usefulness of the EP Flux, having it heading in that direct is a major bonus!. I can't help but wonder whether something will just happen within the deterministic and ensemble models within the next 7 to 10 days for example. I am currently on the main forecasting shift for work, of which includes producing the daily 14 day forecast, of which is an absolutely b*tch at the moment beyond days 8/9 in particular, to the point where attempting a broad analysis and summary is difficult, let alone the usual required details.

The 00Z and now 06Z GFS which builds high pressure over Greenland and creates a block akin to that of 09/10 for example is clearly interesting, but I wonder whether it is too soon. As you highlight the situation has to stabilise first and any energy/vorticity moving across Greenland, as you highlight, would stop the kind of charts/synoptic pattern that the GFS Det is currently producing, at least for a time.

That being said, using the ECMWF 32 day forecast as a basis as well in relation to your thoughts, I would image that any significant cold outbreak in December would come due to a blocking high to the N or NW of the UK and not a Scandinavian high. Personally I prefer the former, just preference given location in the UK!.

Clearly there remain some fascinating signs and signals, but until it happens it is nothing more than forecast information on a chart, but I agree, the mid-month period and beyond does indeed look particularly interesting to say the least!...

Cheers, Matt.

[Methuselah]

Thanks for the input Matt & Chio...

[lorenzo]

Great update C. That is a rarity on the EP Flux charts ! Constant of temps heading south having a brief respite... perhaps something more.. http://ds.data.jma.g...ikei_12z_nh.gif

Good luck with that forecast Matt, days 8/9 are a lottery with the aforementioned reformation, that's my favourite word of today !!

Looking very busy at the top of the strat also.. almost poised for a double whammy.