Stratosphere Temperature Watch 2011/2012

[geoffw]

by looking at ECM how wrong can i be!!!

[Isolated Frost]

I can't help but think, that that despite the fact that a cold outbreak is v.likely within the next 5-15 days, and potentially a severe one, with some potent blocking high synoptics as the aleutian ridge moves into siberia.. but then the pv builds again, regardless of the probable surface high o/greenland.. I think one or two more warmings are needed before january closes, most favourable quite strong and n.pole orientated.

We have slowly doused the fire that is the pv, as proven by the prominent blocking high over alaska currently, and the projected shift west of the pv into baffin/nunavut soon... but we need more water (strat warming) as the fire is contagious. Just a couple buckets more, but we need it soon...

[Partholon]

I can't help but think, that that despite the fact that a cold outbreak is v.likely within the next 5-15 days, and potentially a severe one, with some potent blocking high synoptics as the aleutian ridge moves into siberia.. but then the pv builds again, regardless of the probable surface high o/greenland.. I think one or two more warmings are needed before january closes, most favourable quite strong and n.pole orientated.

We have slowly doused the fire that is the pv, as proven by the prominent blocking high over alaska currently, and the projected shift west of the pv into baffin/nunavut soon... but we need more water (strat warming) as the fire is contagious. Just a couple buckets more, but we need it soon...

with this post in mind:

Sorry if this is in the wrong forum, but what was the state of the stratosphere back in the winters of 1947 and 1962/63? Was the stratosphere warm throughout those prolonged cold spells, or was it a case that the initial warming created such huge blocking highs, that they couldn't be dislodged despite the stratosphere cooling down? Last year, according to the experts, it seems once the stratosphere started to cooled down in December, our chances of cold returning were low. So i suppose my question is can blocking highs sometimes be sustained, even if the stratosphere cools down significantly?

[Glacier Point]

During the early and mid part of the winter of 1962/3 the stratosphere was warmer than normal but notably cooled during February.

If we do go cold, I think that may not be a bad thing for tropospheric blocking. Take 1986 for example, currently a very similar profile..

The cooling stratisphere following a warm period in January led to a strong blocking signal during February.

We now have actual evidence of our second minor warming event with zonal wind anomalies showing a dramatic decrease right down to 150hPa. That's the one we're seeing coming onto the model horizon.

Hi GP.

I was definately in the camp that thought significant mountain torques due to the MJO were the main source of warmings and I am not quite so confident about that now. Rather I think it might be one source, with lesser mountain torques playing a significant part depending on their latitude. By significant mountain torques I am thinking about across Asia/Himalayas , US/Rockies and South America. By lesser mountain torques I am thinking about Greenland and Norway in which case the state of the AO may play a part and the MJO in a different way. I would be interested to here your thoughts on this ?

Hi Mark, good to see you back. Hard to differentiate them. If we called them both a +AAM poleward tendency, that would cover it. Reanalysis plots depict nicely the torque events and also the positive tendency angular momentum waves appearing at high latitude. Instinctively given the magnitude of torques centred around 30N in terms of addition of westerly wind anomalies, I would tend to go for these as being one of the contributory factors.

Edited January 12, 2012 by Glacier Point

[weatherjunkie]

GFS showing some nice warming over Greenland/N. Atlantic in the lower stratosphere with what I'm assuming is local wavebreaking action. As noted by a few, the top of the stratosphere is showing an significantly weakened PV. The problem is getting this to occur at lower levels and it appears the GFS wants to restrengthen the mid-stratosphere vortex a bit. More warming over Siberia is expected but EP fluxes remain unfavorable.

ECMWF actually is showing a wave 3 signal in the lower stratosphere plots.

It'll be an interesting few weeks...

[Snowman31]

Hi guys, is there any new updates today??

[greybing]

..........................its the apocalypse

[Great Plum]

Hello all, just wondering if there was any news from tomight's updates... I had a look but can't make head nor tail!

[chionomaniac]

Hello all, just wondering if there was any news from tomight's updates... I had a look but can't make head nor tail!

Hi GP, I have been really busy today. Will update tomorrow.

[damianslaw]

Very quiet in this thread today - no updates, mm not sure if this is good news or bad news.. last saturday this thread was the thread to be in, but alas the projected strat warming appears to be stuttering somewhat.. any updates?

[summer blizzard]

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_2011_merra.pdf

Not sure what the impact on zonal winds has been yet but the stratosphere is now warmer than at anytime last winter at 30mb and warmer than average right down to 100mb.

[weatherjunkie]

Quick synopsis of the latest data:

GFS/ECMWF showing PV propagation to the pole at almost all levels, with the GFS being quite aggressive in indicating PV recovery while ECMWF still tries to retain some form of a split at the mid-levels and a weakened upper strat PV state. Both do however exhibit signs of a wave two type pattern. Zonal charts from the ECM indicate strong rebound of westerlies from 5-30 hPa between 60 and 80N. Momentum/heat fluxes weaken significantly by day 10 according to the Euro from planetary waves 1 and 2.

Temp anomaly obs indicates downwelling of the +anomalies that were a product of previous warmings. This should help to drop AO in the short term. Most lower strat charts and tropospheric models indicate transient -NAO signals, so we again wait for chance of sustained cold. But hey, EP fluxes are neutral toward the end of the forecast period instead of equatorward, so that's some good news.

[chionomaniac]

Todays update.

We are seeing a tropospheric divergence of opinion between the GFS and the ECM and I believe that this is being stratospherically led due to differences in modelling the weakened lower vortex.

We can see quite clearly on the ECM forecast, even at the 30 hPa level, that a lobe of vortex breaks away from the stretched vortex right towards the UK.

This is what leads to the tropospheric dropped trough into Europe with a resultant easterly on the ECM charts.

The GFS however is having none of this, and instead keeps the stretched vortex intact.

Whichever model has the stratospheric modelling correct will also have the tropospheric modelling correct. We do not know yet.

One thing to note on those charts is that the warming has significantly reached the 30 hPa level.

At the top of the stratosphere a large warming is currently occurring that knocks the vortex off the polar leaving a forecast week of mean zonal winds . However the mean zonal winds do not reverse lower down in the vortex due to the EP flux diverting the warming sufficiently equator wards to prevent full integration of the warming into the heart of the vortex as can be seen below at 10 hPa and T+120 :

There are signs that the EP flux may become more favourable later, but I suspect that this could be too little too late.

The warming of the stratosphere is great to see and will give the second half of winter a better chance of colder outbreaks. However, the jury is still out on whether sustained high latitude blocking can be achieved. This may well depend on how any weakening westerlies are maintained in the lower stratosphere allowing local wave breaking from the troposphere to prevail.

c

[phil nw.]

Yes still the warmings remain at the higher levels as you say Chiono.

Interesting to see the link between the lowest level of the Strato.and our trophosphere wrt the modelling of the pattern at T144.

We can see on the GFS 100hPa pressure chart how well this correlates with the 500hPa modelling

Going on to the outlook and looking at the ECM forecasts.Those warmings are still forecasted to remain above mid-level -here days 5 and 10

showing the mean zonal wind speeds still positive and trending up,if anything-again days 5 and 10.

This doesn`t promise extensive arctic trophospheric blocking without further vortex disruption further down,but at least chances of cold incursions from a weakened vortex are better than what we had earlier in the Winter.

[damianslaw]

Do any of the experts have any comment on the prospect of a SSW - by their nature don't these tend to occur suddenly out of the blue and can't be ruled out. Last Saturday it all sounded very positive, now it has all gone very quiet - it is all a bit too complex for me but I enjoy reading the posts in this thread.

[phil nw.]

Do any of the experts have any comment on the prospect of a SSW - by their nature don't these tend to occur suddenly out of the blue and can't be ruled out. Last Saturday it all sounded very positive, now it has all gone very quiet - it is all a bit too complex for me but I enjoy reading the posts in this thread.

The latest data we have and updated today show plenty of minor warming at the higher levels,which have currently weakened and somewhat fragemented the vortex.

Mean Zonal winds have started to slow but not to the point of reversal. So these minor warmings can be forecasted from the downwelling data.

SSWs i believe stem from a major warming whereby we get warming at the lower levels as well which then result in zonal wind reversal which completely disrupt the vortex.

I am sure i have read somewhere that a SSW can also be initiated by local wavebreaking events whereby disruption can occur at the bottom levels caused by rossby waves entering the vortex at trophospheric level and upwelling.These come from mountain torques or land/sea temperature contrasts.

Maybe Chiono can confirm this,although i am not sure how accurately these can be forecasted.

If one does occur though, as you suggested, they can quickly reverse zonal winds within 5-10days whereas a top down reversal cantake 3-6 weeks.

this link might prove usefull

http://climate.ncas....ntinuum-warming

I hope this helps.

[Partholon]

not looking too good according to this guy:

Matthew Hugo @MattHugo81 1h Reply Retweet

...mean zonal wind set to increase above 20 to 30hPa now longer term from the ECM = renewed support for +NAO/Atlantic weather..

I guess a positive slant on this might be that it takes a few weeks for the effects of this to show up on the models

[phil nw.]

not looking too good according to this guy:

Matthew Hugo @MattHugo81 1h Reply Retweet

...mean zonal wind set to increase above 20 to 30hPa now longer term from the ECM = renewed support for +NAO/Atlantic weather..

I guess a positive slant on this might be that it takes a few weeks for the effects of this to show up on the models

Yes i can see where he`s coming from.I did mention that zonal winds ,although currently slower,were trending up in yesterdays forecast data by day10 -my post 953.

Edited January 15, 2012 by phil n.warks.

[Weather-history]

not looking too good according to this guy:

Matthew Hugo @MattHugo81 1h Reply Retweet

...mean zonal wind set to increase above 20 to 30hPa now longer term from the ECM = renewed support for +NAO/Atlantic weather..

Then you have Glacier Point saying it might not be a bad thing for it to happen.

Confusing?!

[phil nw.]

Then you have Glacier Point saying it might not be a bad thing for it to happen.

Confusing?!

Yes it is Mr.D,maybe when he has time i am sure GP will post his views on this.

I admit i am not sure what he means -maybe there are other over-riding factors at play in the background that will impact on the Vortex.

I see no sign of complete disruption yet, and the lack of real stable Arctic blocking(yellows at 500hPa) does correlate with the positive zonal winds at the mid and lower levels.

This would explain why there`s enough vortex strength still showing over W.Greenland which is flattening any attempts at Atlantic ridging.

We need something out of the hat soon.

Edited January 15, 2012 by phil n.warks.

[chionomaniac]

Yes it is Mr.D,maybe when he has time i am sure GP will post his views on this.

I admit i am not sure what he means on this.

I see no sign of complete disruption yet, and the lack of real stable Arctic blocking(yellows at 500hPa) does correlate with the positive zonal winds at the mid and lower levels.

This would explain why there`s enough vortex strength still showing over W.Greenland which is flattening any attempts at Atlantic ridging.

We need something out of the hat soon.

What GP means Phil, is that as the motor starts back up at the top of the stratosphere it pushes the negative mean zonal anomalies down to lower levels. Perhaps suggested here:

This will be aided somewhat by the warming seen to be forecast at the 30 hPa level which will have an influence there. And remember the stratosphere has taken a big hit. We have come close to achieving a SSW but have missed one by a latitude of just 10º. The polar vortex is not about to reform and be back to the strength that it was before Christmas especially as it will normally be reducing now anyway.

There is still plenty of winter left and I don't believe that the tropospheric vortex will be stable. Whether we get anything of promise is another matter.

Edited January 15, 2012 by chionomaniac

[phil nw.]

What GP means Phil, is that as the motor starts back up at the top of the stratosphere it pushes the negative mean zonal anomalies down to lower levels. Perhaps suggested here:

This will be aided somewhat by the warming seen to be forecast at the 30 hPa level which will have an influence there. And remember the stratosphere has taken a big hit. We have come close to achieving a SSW but have missed one by a latitude of just 10º. The polar vortex is not about to reform and be back to the strength that it was before Christmas especially as it will normally be reducing now anyway.

There is still plenty of winter left and I don't believe that the tropospheric vortex will be stable. Whether we get anything of promise is another matter.

Yes pretty much agree with your summary.The Vortex is certainly weaker,that can be seen by the 500hPa modelling.

Those Zonal wind forecasts indicate some increase to day 9 and i see from the last image the previous decrease is forecasted to work down to the lower level.Let`s hope that continues.

[bluearmy]

What GP means Phil, is that as the motor starts back up at the top of the stratosphere it pushes the negative mean zonal anomalies down to lower levels. Perhaps suggested here:

This will be aided somewhat by the warming seen to be forecast at the 30 hPa level which will have an influence there. And remember the stratosphere has taken a big hit. We have come close to achieving a SSW but have missed one by a latitude of just 10º. The polar vortex is not about to reform and be back to the strength that it was before Christmas especially as it will normally be reducing now anyway.

There is still plenty of winter left and I don't believe that the tropospheric vortex will be stable. Whether we get anything of promise is another matter.

ed, i just posted this in the mdt but the parallel ens seem intent on pretty well destroying the canadian vortex by the end of jan. seems a bit sudden ? the normal gefs not quite as keen - i assume the NOAA strat stuff will still be coming from the normal gefs modelling rather than the parallel.

[chionomaniac]

ed, i just posted this in the mdt but the parallel ens seem intent on pretty well destroying the canadian vortex by the end of jan. seems a bit sudden ? the normal gefs not quite as keen - i assume the NOAA strat stuff will still be coming from the normal gefs modelling rather than the parallel.

Interesting as I have just posted that we need to see that in the model thread!

Great minds heh?

[cooling climate]

not looking too good according to this guy:

Matthew Hugo @MattHugo81 1h Reply Retweet

...mean zonal wind set to increase above 20 to 30hPa now longer term from the ECM = renewed support for +NAO/Atlantic weather..

I guess a positive slant on this might be that it takes a few weeks for the effects of this to show up on the models

Matt Hugo's latest ECM 32 day update was as he put it the best he's seen for northern

blocking since December 2010 with a clear indication from the model of easterlies from

23rd to 29th then Greenland blocking and north/northeasterlies 6th to 12th Feb.

The dates are unimportant its the fact their sounds of though their was a strong signal

for northern blocking.

Considering how accurate the ECM 32 dayer has been I find it strange that given the strong

indications of a cold outlook (this is the second update to show this) he has downplayed

this with no blogs on netweather and only a couple of references on (TWO) and now he is

talking of a stronger signal for a +NAO.

Could the GFS profiling of the stratosphere with a much more +NAO and stronger Vortex

be proving correct I wonder.