Stratosphere Temperature Watch

[Guest North Sea Snow Convection]

Zonal winds are forecast to stay strongly negative in the middle stratosphere (10-30 hPa)for a good period of time that may well exceed 10 days! Remember the longer these winds are negative in the stratosphere, the longer duration tropospheric impact.The initial propagation down the troposphere is quick and strong which is probally partly responsible with the topsy turvy modelling at present.

However even after this the mid range impacts of the SSW are indeed looking good.

c

Well we have been commenting on how this MMW has got stronger and stronger and I'm sure you will agree with me that the expectations regarding the extent of the polar easterlies has just kept upgrading and exceeded our expectations. The odds on cold convergence of polar air in our neck of the woods must be high now when you consider the length of time that easterly zonals are now predicted to dominate.

This type of thing is a joy to see And there is day after day of negative values as you say.

Edited January 26, 2009 by North Sea Snow Convection

[sandstorm2]

This thread is becoming more fascinating every day and it is just a matter of time before we see the impact of this warming, its just a case of being patient but even if nothing comes of it, it has certainly been a real eye opener to me, it has taken me out of my blinkered view of the models and made me look at the wider view of the atmosphere as a whole.

SS2

[Stu_London]

This thread is becoming more fascinating every day and it is just a matter of time before we see the impact of this warming, its just a case of being patient but even if nothing comes of it, it has certainly been a real eye opener to me, it has taken me out of my blinkered view of the models and made me look at the wider view of the atmosphere as a whole.

SS2

and what does SS2 stand for?

[chionomaniac]

Well we have been commenting on how this MMW has got stronger and stronger and I'm sure you will agree with me that the expectations regarding the extent of the polar easterlies has just kept upgrading and exceeded our expectations. The odds on cold convergence of polar air in our neck of the woods must be high now when you consider the length of time that easterly zonals are now predicted to dominate.

This type of thing is a joy to see And there is day after day of negative values as you say.

Yes this MMW certainly has exceeded expectations. A couple of things. History has shown that it is extremely difficult to get any type of negative mean zonal wind at the 30 hPa level during a winter month. If MMWs were measured by this then there would only have possibly been 1 or 2 since 1980. The 30 hPa mean zonal winds (not anomaly!) are forecast to be greater than -10m/s for a number of days. This again has never been seen in the NCEP data since 1980. Another unprecedented event (if it verifies). We truly are looking at a MMW like no other!

Furthermore the zonal mean winds seem to wane slightly before again increasing for the forecasted T+240!

The models are understandingly having difficulty translating this into a reliable prediction. However I can see what they are trying to resolve/ predict. Here is the lower stratosphere forecast at the level 100 hPa for T+240 (on its side on purpose).

And here is the GFS 200 hPa jet profile for the same time:

There are certainly some similarities to be seen.

c

Edited January 26, 2009 by chionomaniac

[sandstorm2]

and what does SS2 stand for?

Its just a shortened version of my username, sand storm2

[Stu_London]

Its just a shortened version of my username, sand storm2

Ok, thanks for clearing that up

[Glacier Point]

Current zonal wind profiles show an extremely efficient propagation with good fluxing and downwelling with westerly winds ahead of it weakening rapidly.

It cannot be emphasised the record strength of this MMW, and the propagating may be the most severe yet recorded. The last event which looked anywhere near this was in the 1980s.

Projecting forward on the basis of ECM forecasts and CPC Ensemble AO mean:

http://strat-www.met.fu-berlin.de/cgi-bin/...xes&alert=1

http://www.cpc.ncep.noaa.gov/products/stra...JFM_NH_2009.gif

http://www.cpc.ncep.noaa.gov/products/prec...ndex_ensm.shtml

Some serious signals for serious blocking to take effect. What we are seeing in the current modelling is likely to be very moderate by comparison. The benchmark is the record for -AO in February....1969 (-3.114).

Edited January 26, 2009 by Glacier Point

[stricklands1984]

im a noob but does this MMW mean we could possibly severe cold?

[chionomaniac]

Some serious signals for serious blocking to take effect. What we are seeing in the current modelling is likely to be very moderate by comparison. The benchmark is the record for -AO in February....1969 (-3.114).

That is almost a ramp GP!

Great chart showing the extent and longevity of possible blocking.

I think I chose a good year to start a stratosphere thread!

c

[tundra]

im a noob but does this MMW mean we could possibly severe cold?

In a word yes, although its not guaranteed there is a high probability but it also means that we could be looking at a very prolonged spell of very cold weather.

[Just Below Zero]

In a word yes, although its not guaranteed there is a high probability but it also means that we could be looking at a very prolonged spell of very cold weather.

Yeah tundra but what does it mean?

[Duane S.]

Yeah tundra but what does it mean?

Major Mid-winter Warmings (MMW).

SSW is also being banded round a lot at the moment as well which stands for Sudden Stratospheric Warmings.

[tundra]

Now that has to be some sort of record. Incredible.

[chionomaniac]

That spike does look impressive! Do any of the guys, who study these events, have any comparable spikes to show? and ,if so, what were the impacts later on?

With so many strange things occurring (unprecedented Arctic melt, cold PDO being warmer than is usual etc.) could this be another 'novel' event?

Here is comparison chart with max/min on. But it hasn't updated yet. It it agrees with the JMA then we could have a record at this level also. Hopefully have more time to complete days analysis later.

c

[Bermuda Skies]

I have been following this thread with considerable interest. The quality of the posts and the knowledge of the posters is first class.

I found this website (sorry if its already well known) which may be of interest to novices like me and the more experienced alike. It has some very cool animations of previous events going back to 1953.

Thanks again for this fascinating thread.

Columbia University SSW Website

[Chris Knight]

Here is comparison chart with max/min on. But it hasn't updated yet. It it agrees with the JMA then we could have a record at this level also. Hopefully have more time to complete days analysis later.

c

Interesting that the Winter temperature spikes seem to occur on or very near dates where there have been previous spikes in the maximum series - viz. the current one and those of late January and late February in 2008.

Does anyone know where the numerical data is archived, since the CPC page only gives graphical data?

[Guest North Sea Snow Convection]

That spike does look impressive! Do any of the guys, who study these events, have any comparable spikes to show? and ,if so, what were the impacts later on?

With so many strange things occurring (unprecedented Arctic melt, cold PDO being warmer than is usual etc.) could this be another 'novel' event?

It is certainly an unprecedented event in strength but a regular winter phenomenon that has nothing to do with what you would like it to. Can we please leave your pet subject out of this thread and keep it on the climate threads where you can talk about it 24/7.

Many thanks, assuming chionomaniac/mods etc agree

[Richie V]

It is certainly an unprecedented event in strength but a regular winter phenomenon that has nothing to do with what you would like it to. Can we please leave your pet subject out of this thread and keep it on the climate threads where you can talk about it 24/7.

Many thanks, assuming chionomaniac/mods etc agree

Fully agree NSSC

[chionomaniac]

It is certainly an unprecedented event in strength but a regular winter phenomenon that has nothing to do with what you would like it to. Can we please leave your pet subject out of this thread and keep it on the climate threads where you can talk about it 24/7.

Many thanks, assuming chionomaniac/mods etc agree

Yes I agree. The purpose of this thread is to monitor how the changes in stratospheric conditions affect us at a tropospheric level, for this winter. That's all.

[Guest North Sea Snow Convection]

Yes I agree. The purpose of this thread is to monitor how the changes in stratospheric conditions affect us at a tropospheric level, for this winter. That's all.

So this morning we continue to see the polar easterlies hold sway with negative zonal winds at 10 and 30hPa still predicted to keep going throughout

The sequence adds on another day!

[karyo]

Interesting that the Winter temperature spikes seem to occur on or very near dates where there have been previous spikes in the maximum series - viz. the current one and those of late January and late February in 2008.

That's an interesting observation and certainly quite often one major strqtospheric warming is followed by others! This happened for example late last winter. The difference this time, is that the stratospheric temperatures are not falling quickly after the main event but very slowly which is a good things for more long lasting effects (i.e. northern blocking).

I wonder what do the experts think about the possibility of further warming events occuring into February?

Edit: i've just read GPs and SMs posts in the model output thread - potential for further warming events to be trigerred.

Karyo

Edited January 27, 2009 by karyo

[memories of 63]

Now that has to be some sort of record. Incredible.

Is the slight warming event we saw at the end of December in the right time frame to explain the predicted upcoming cold spell?

[tundra]

Is the slight warming event we saw at the end of December in the right time frame to explain the predicted upcoming cold spell?

I can't say for certain but there probably is some correlation. This warming is much much stronger and longer lasting and because the zonal winds have also dropped through the floor i believe it will propagate down into the tropopause alot quicker,we will not have to wait 20+ days to see the effects.

[chionomaniac]

So this morning we continue to see the polar easterlies hold sway with negative zonal winds at 10 and 30hPa still predicted to keep going throughout

The sequence adds on another day!

Yes the recovery of the stratospheric vortex still seems a long time in coming (if at all and we don't enter a final warming).

There are signs, but in 10 days, that the 30 hPa level may start to undergo some vortex reformation, but I do wonder what the longest time ever recorded with winter easterlies at 10 and 30 hPa has been. This is certainly one strong vortex split.

Today at 10 hPa vortex split proceeding

5 day forecast - high pressure dominant

10 days still no vortex reformation but slight high pressure weakening

c

[Mr Maunder]

c,

Those charts are pretty impressive and dramatic - and if high pressure does set up as shown then it is going to get very interesting indeed for the UK!

I think that most of the pieces look to be in place for an extended period of above average heights in the NH.

But, of course, we have never been in this precise situation before so it is just a question of waiting and watching - and seeing how the models deal with this.

MM