Stratosphere Temperature Watch 2012/2013

[bluearmy]

A really defined Greenland ridge starting to show at 100mb now - cracker!

at the lowest point in the strat and at day 10, this is the least reliable chart on this suite

[Cloud 10]

Temperatures still spiking at 10mb and 30mb.

[feb1991blizzard]

at the lowest point in the strat and at day 10, this is the least reliable chart on this suite

What would you class as a reliable time frame at 100mb then, in terms of a reasonable verification rate?

[bluearmy]

What would you class as a reliable time frame at 100mb then, in terms of a reasonable verification rate?

i generally see the day 10 100mb reflects the operational trop at day 10. given the unreliability of that, i dont have too much faith below 50hpa at day 10.

[feb1991blizzard]

i generally see the day 10 100mb reflects the operational trop at day 10. given the unreliability of that, i dont have too much faith below 50hpa at day 10.

Given whats happening lately making H500 GFS operational even more unreliable then, i wont bother posting any of them past day 6!, cheers

[Jonan92]

Third warming showed again

[shuggee]

Temperatures still spiking at 10mb and 30mb.

Going to be an interesting end to January/start of Feb

[Interitus]

A few points on the excellent bit of research by Interitus:

1) many of the Cohen events are, I believe, late season or even final warmings warmings which have quite different dynamics for us due in part to the lack of cold pooling in the NH. However, I suspect having tried to do something similar that it may not make a huge difference to exclude these. It does show that an SSW is no guarantee of cold for the British isles and we should certainly bear that in mind.

This is not quite correct, the Cohen list uses the standard first day of 10hPa reverse flow; two of the warmings are in November. Martineau uses the date of minimum 10hPa NAM which averages 2-3 days later than Cohen but most of the same events are agreed upon, including the earliest and latest.

Certainly many are late season, with over a fifth occurring in March, and the effects can be seen in the indices though maybe not as memorably as a mid-winter event.

I've now incorporated the NAO and AO data to the CET and SSW list and am still poring over the figures. A couple of noticeable features - on average - are the strong, rapid, negative response of the AO after the SSW date, but the positive NAO actually strengthens for a while. Both responses are noticeable within a week and last roughly 4 weeks by which time they have returned closer to normal. Then there is a second downturn in the AO, not as strong as the first, and the NAO trends negative. This phase lasts about 2 weeks.

Remembering the CET graph posted previously, the two phases link very well the initial cooling, recovery and secondary cooling but note that there appears to be a greater covariation or linkage between temperature and the AO rather than the NAO which doesn't represent blocks to our east well.

One trouble with the analysis is that it is hard to easily discern the actual effects of the SSW. They are not some oddity but an intrinsic feature of the NH winter - within the span of 61 winters examined there are 55 SSW, with only 15 winters without them for comparison which means the index long term averages all contain a large amount of SSW influence. Also there are as many cold spells prior to SSWs than after and clearly the majority of SSW years are not brutally cold.

[chionomaniac]

Can't wait to see the detailed results there, Interitus. I wonder how many times that immediate great drop in AO resulted in an easterly for the UK - the NAO doesn't have to be negative for this to occur.

[Glacier Point]

I've now incorporated the NAO and AO data to the CET and SSW list and am still poring over the figures. A couple of noticeable features - on average - are the strong, rapid, negative response of the AO after the SSW date, but the positive NAO actually strengthens for a while. Both responses are noticeable within a week and last roughly 4 weeks by which time they have returned closer to normal. Then there is a second downturn in the AO, not as strong as the first, and the NAO trends negative. This phase lasts about 2 weeks.

Remembering the CET graph posted previously, the two phases link very well the initial cooling, recovery and secondary cooling but note that there appears to be a greater covariation or linkage between temperature and the AO rather than the NAO which doesn't represent blocks to our east well.

One trouble with the analysis is that it is hard to easily discern the actual effects of the SSW. They are not some oddity but an intrinsic feature of the NH winter - within the span of 61 winters examined there are 55 SSW, with only 15 winters without them for comparison which means the index long term averages all contain a large amount of SSW influence. Also there are as many cold spells prior to SSWs than after and clearly the majority of SSW years are not brutally cold.

Might be worth separating the data into winters with observed MEI > +/- 1 value; and previous summer GLAAM value where this exceeded -1 or +1 as this might give an insight into lagged Brewer Dobson / entrenched tropospheric pattern.

[Jonan92]

Third warming shown again

[Iceni]

The Daily Mail makes quite a decent fist of explaining what an SSW is here with great little video from the MetO at the end (now I understand what triggers a SSW ):

http://www.dailymail...use-freeze.html

Never thought I'd see the day when atmospheric science made it onto the front page of the Mail, but got to be good news. People are sniffy about the old DM, but now and again, their science and tech pages make excellent reading — they actually employ science editors who seem to know what they're on about, unlike the Telegraph (Louise Gray) Guardian (the Moonbat) or Times.

Edited January 9, 2013 by Iceni

[Luisport]

http://raleighwx.americanwx.com/models/euro/00zecmwfnao.gif

[Benny123]

Might just be worth a little look. Seems as though the BBC are also in favour of recent Stratosphere events.

http://www.bbc.co.uk/weather/feeds/20964928

[chionomaniac]

Might just be worth a little look. Seems as though the BBC are also in favour of recent Stratosphere events.

http://www.bbc.co.uk.../feeds/20964928

Thank you for that Ben. I think we can safely say that those who still don't believe who the stratosphere as an important driver are most definitely in the minority now!

[Luisport]

Matthew Hugoâ€@MattHugo81

Just telling it as it is but the 12z EC ENS are the coldest of the last few days. Pretty much unanimously cold throughout next week now.

[Rocheydub]

My understanding of the strat is microscopic compared to GP, Chiono etc, but I have learned a lot because of this thread. I did however, embarrass myself (schoolboy errors) today in a big way on an Irish weather website!

To this end, I am still a student with the dunce hat on... But I am forever in debt of Chiono, GP and recretos of late, for their terrific knowledge, and their ability to share this emerging and ever growing science...

My reason for this post? To congratulate Chiono for his excellent work, and the very latest confirmation of his work by bodies such as UKMO and now the BBC! In the immortal words of Andy Grey: Tikaboo son, tikaboo!

[cooling climate]

Below is a height- latitude cross section of zonally averaged zonal wind in the northern hemisphere.

The warm colours are easterly winds.

Wow what a change. Just a couple of days ago the area above 60-90n was blue (strong westerly

winds) now they are strong easterly.

[picog]

Impressive warming — that's nearly a 40C difference in a few days!

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/html_e/pole30_n.html

[Tamara]

Those AO/NAO correlation with SSW studies are very interesting wrt to the current tropospheric representation of the SSW we have of the here and now. Pertinent completely to the GFS vs Euro model differences in terms of undercutting energy or stronger push in the northern arm of the jet, making the difference between a - or + NAO.

If we assume an -NAO lag period as suggested above, then there is indeed some case for the most favourable NAO response arriving late in the month and into February which will assist in backing the displaced cold air from the pole further and further south and west - much as expert opinion suggests. Especially as further warming is suggested on stratosphere forecasts to help perpetuate a virtuous (cold blocked) pattern further into the remainder of winter. In that respect any (relative) interim cooling at the higher 10hPa level should act as a favourable squeeze for lower propagation of warmer layers down towards the troposphere - with the cycle repeated as another top warming, as forecasted, is applied. That is the theory anyway

[Buriedundersnow]

this might be off topic and sorry to the mods if it is.

people should have a look at spaceweather.com and there first bit at the top they have a link to a thing that nasa have done where they say they have pulled in dozens of experts to do a paper on the affects the suns varying output and the affects that it then hs on the upper atmosphere and then our climate it might help add to things chio and gp and the rest are already working on with the strat on stuff

[SteveB]

_{Do we have an update on the state of the current warming, what with the chopping & changing in the model thread, it would be nice to have some positive news (if there is any still)} Edited January 10, 2013 by SteveB

[snowking]

_{Do we have an update on the state of the current warming, what with the chopping & changing in the model thread, it would be nice to have some positive news (if there is any still)}

I'm on my phone so I havnt had a chance to take a proper look, but looking very briefly:

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2013011000&var=HGT&lev=100mb&hour=096

Vortex centre around Canada but influence into W Greenland, suggestion of a ridge into Scandi and some forcing north towards Svalbard.

The pattern, as has been expected throughout, then retrogresses, so that by 168:

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2013011000&var=HGT&lev=100mb&hour=168

Forcing of the ridge is more Greenlad based

Even more apparant at 10mb:

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2013011000&var=HGT&lev=10mb&hour=168

All of this said, these charts can't account for mesoscale features at the surface, but certainly nothing to be concerned about stratospherically

SK

[SteveB]

Cheers SK

[Zenarcher]

Temperatures still rising and appears to match the temperature we had in mid November.

No sign of stopping.

Edited January 10, 2013 by weathermaster