Stratosphere Temperature Watch 2011/2012

[chionomaniac]

Tasty ECM today. Full update later

[bluearmy]

Tasty ECM today. Full update later

surely you expected some of it, given yesterday's 12z op ???

[mountain shadow]

Tasty ECM today. Full update later

A SSW I hope? :rofl:

[chionomaniac]

surely you expected some of it, given yesterday's 12z op ???

Never take anything for granted!

A SSW I hope? :rofl:

No.... but a step towards.

Today we see the best stratospheric ECM forecast of the season so far. This is probably in response to the latest strong Asian MT event that has caused wave breaking up into the stratosphere. With the stratospheric vortex already slightly weakened by the previous warming events wil this latest warming be enough for a knockout blow?

Well we can't tell yet but signs are encouraging.

Firstly we have another negative zonal mean wing forecast right at the top of the stratosphere (1hPa) at T+240.

This is strong enough to displace the vortex off the pole at this level .... but we need to see propagation down to lower levels for this to have any effect on the troposphere.

Signs are good, firstly we have a reduced mean zonal wind, due to the displacement, throughout the stratosphere. At the 10 hPa level both the warming and displacement is evident.

This is the crucial level that mean zonal mean winds would have to reverse at 60N to achieve a SSW.

However, I am more interested at this stage in how any stratospheric disturbances are played out tropospherically rather than achieving a technical SSW.

To look at this we need to look even lower down the stratosphere and for the first time the displacement of the vortex is forecast to have strong effect at the 100 hPa level.

Here we see both a displacement and split of the vortex. This is so positioned that initailly we would a receive a northerly flow - no toppler here due to the lack of strong vorticity on the western Atlantic side.

How things develop from here hold a lot of interest - where will the vortex go next?

I am unable to say so far but hopefully the GFS will give us a clue later.

For those who have been following the stratosphere this winter we could be seeing a winter that demonstrates very well why a favourable or unfavourable stratosphere is so important on tropospheric weather patterns.

c

[johnholmes]

Nothing as technical as your posts chio but I note the 30mb chart shows a dip again?

[chionomaniac]

Nothing as technical as your posts chio but I note the 30mb chart shows a dip again?

By looking at one spot directly over the NP, John you miss the intricacies of the vortex behaviour.

Check out the 30 Hpa forecast here.

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=30&forecast=all&lng=eng

[chionomaniac]

GFS update trends are good as well this morning.

The only drawback is that it is not until T+240 that the vortex show signs of leaving Greenland.

However, we see a forecast of significant warming at the 30 hPa level for the first time.

[phil nw.]

Yes plenty of signs of the Vortex displacement in those images C.

Signs too in the ECM forecasts of a further Asian Mountain Torque kicking off in the later frames ,if i am reading this right.

So the warming out of the Vortex looks set to continue.

The GFS T240 Vortex placement would be in line with Trophospheric modelling around day 10

However there`s still some trend in the Trophospheric charts to reform this over Greenland later.Todays 006z run does this.

Maybe a later wavebreaking as suggested by the ECM forecasts will give it a further blow and this wil eventually show in later modelling at 500hPa levels.

[chionomaniac]

I think that as good as modern super computers are Phil, that it must be very difficult to work out how a changing stratosphere profile affects the tropospheric output. The GFS is keen on the latest output to follow the ECM lead then (after T+240 on the 6Zgfs) regress the polar back across to the west of Greenland.

However, I think that there is a lot of uncertainty with the lower stratospheric forecasts from around 7 days, and therefore we may get indications but nothing solid on what will occur after this period. I am concentrating both stratospherically and tropospherically on the 7-10 day period for the time being and suggest others do the same.

There is likely to be a big crossroads ahead determining where and if any northern blocking will set up. We could see just as easy see the weakened PV still entrenched where we least would like it, whilst other areas of the hemisphere see HLBs.

I won't be putting any money on where a HLB is likely to sit at this juncture - that is for sure!

[phil nw.]

Yes i agree a lot of doubt about where the vortex core energy will place itself in the medium term Ed.

As you know i have previously posted that i think we are more likely see a Vortex displacement than a complete shredding in the timeframe we are talking about,simply because the warmings are not yet dramatic enough for that,--imo,of course.

I have a fear that the Aleutian ridging will push the main body of the Vortex towards our side of the Pole and for a while we may struggle to get heights into the Arctic over here.That`s maybe what the GFS is picking up on.

Still with more wavebreaking on the horizon there could better vortex disruption a little later--hopefully not too late into Winter though.

I will say though Ed. it`s fascinating stuff this- to be able to study the link between the 2 levels of the Atmosphere.

Edited January 4, 2012 by phil n.warks.

[chionomaniac]

I will say though Ed. it`s fascinating stuff this- to be able to study the link between the 2 levels of the Atmosphere.

It certainly is - and what a headstart it gave us to go against those forecasting a cold December.

Yes i agree a lot of doubt about where the vortex core energy will place itself in the medium term Ed.

As you know i have previously posted that i think we are more likely see a Vortex displacement than a complete shredding in the timeframe we are talking about,simply because the warmings are not yet dramatic enough for that,--imo,of course.

I have a fear that the Aleutian ridging will push the main body of the Vortex towards our side of the Pole and for a while we may struggle to get heights into the Arctic over here.That`s maybe what the GFS is picking up on.

Still with more wavebreaking on the horizon there could better vortex disruption a little later--hopefully not too late into Winter though.

Phil, I have seen very favourable positioned vortexes at T+240 swing around into unfavourable positions, so I am very open minded. The forecasts change a fair amount when 'events' occur and are far more stable when we are in a Vortex Intensification period.

Edited January 4, 2012 by chionomaniac

[johnholmes]

By looking at one spot directly over the NP, John you miss the intricacies of the vortex behaviour.

Check out the 30 Hpa forecast here.

http://wekuw.met.fu-...ast=all&lng=eng

Oh I'm well aware of missing the intricacies chio-for me the simple life, and I do feel that simply 'spot' watching what is happening not the larger picture of a forecast gives me one small handle to start to look at what may happen 15-25 days or so down the line, using the other factors I usually mention when discussing what I think MIGHT happen.

I do of course read all your posts and hopefully learn a bit more each time-but for me the simple way, right or wrong.

[chionomaniac]

Oh I'm well aware of missing the intricacies chio-for me the simple life, and I do feel that simply 'spot' watching what is happening not the larger picture of a forecast gives me one small handle to start to look at what may happen 15-25 days or so down the line, using the other factors I usually mention when discussing what I think MIGHT happen.

I do of course read all your posts and hopefully learn a bit more each time-but for me the simple way, right or wrong.

I think even the North Pole charts at 30 hPa will show a significant rise over the next ten days.

[chionomaniac]

A look at the mean zonal winds at different layers of the stratosphere highlights both the strong polar vortex conditions that we have seen and the changes already encountered in upper to mid levels of the stratosphere.

First we see that the 10 Hpa temperature is now running above average.

We see that at this level that previous high mean zonal mean winds have dropped below average after the recent wave break but are in the process of regaining strength

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/u60n_10_2011_merra.pdf

However, lower down the stratosphere these winds are still well above average right down to the troposphere.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/u60n_50_2011_merra.pdf

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/u60n_150_2011_merra.pdf

This to me shows how crucial further wave breaks into the stratospherew will be and the importance of these propagating to lower level.

That is what the ECM forecasts today. Will it tomorrow?

[Weather-history]

Interesting! Let the more knowledgable discuss it

http://wekuw.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ts.php?plot=fluxes&alert=1&lng=eng

[chionomaniac]

Yes mr d. Exciting ECM today. Update later!!!

[feb1991blizzard]

Forgive me for my ignorance but isnt this an SSW forecast.

http://wekuw.met.fu-...cmwf1/temps.gif

Edit : Not quite is it, but certainly a massive slowdown of westerlies at the 60N 10hpa level, really looking forward to chiono's update later.

Edited January 5, 2012 by feb1991blizzard

[snow drift]

Yes mr d. Exciting ECM today. Update later!!!

Good morning. I was wondering when your update if you could take each graph and discuss these individualy and possible impact as this would also aide my learning.

Thanks inadvance.

Edited January 5, 2012 by snow drift

[Isolated Frost]

Them charts are fab mr.d, a sudden decrease in zonal wind speed and a sharp but rather small rise in the 30hpa temperature... looking forward to chiono's update as always

[cooling climate]

Excellent stratosphere forcasts this morning from the ECM.

If these forcasts varify then I would say a SSW would be

immenient. Looking through the height charts IE 10mb,

30mb,50mb etc good downwelling seems to be occuring

and the profile of where the heights and vortex is likely to

be look very good for the UK and Europe from a cold

perspective.

[Cecil Hogmanay Melchett]

Very exciting developments today i hope Chino can provide more info later !!

[Radiating Dendrite]

Would I be correct in assuming that the pattern of warming would promote heights over the west of Greenland and a trough over Scandi?

[chionomaniac]

I would agree with you cc.

ECM update:

Starting from the top af the stratosphere, we see a warming forecast for a considerable time that leaves us with the following picture at T+240.

This chart show a considerable warm upper stratosphere with a reducing vortex that looks to be soon overwhelmed by the warming. The forecast mean zonal mean winds are very negative ( -30m/s). During the record breaking SSW of 2009 the mean zonal winds, at this level, bottomed out at around -40m/s, so that gives one an indication of how strong this event could be. The vortex is not completely forecast to disintergrate yet though.

Moving lower now, into the middle stratosphere we see that there is a displacement of the polar vortex forecast at the 10 hPa level that is being recharged by considerable warming.

We have yet to see reversal of the mean zonal winds at this level, but with this type of warming (and if the forecast verifies) then that would be the natural progression.

We see further propagation at the 30 hPa level which continues the theme.

The trend at the lower stratosphere on the ECM is for a complete displacement of the vortex to the Eurasion half of the hemisphere leaving a small area of weaker vorticity that has dropped into East America.

This suggests Atlantic blocking but is the most unreliable part of the forecast. Small shifts in the vorticity centres can lead to very different tropospheric pattern for our small island. We best wait until we have some cross model agreement before establishing where exactly any High latitude blocking will establish. ( An Aleution high looks a safe bet though).

The next chart sees the negative mean zonal winds becoming established in the upper polar atmosphere. Hopefully in the coming days we will see these blues lower further towards the troposphere.

GFS update to follow later.

Edited January 5, 2012 by chionomaniac

[johnholmes]

thanks once more chio for a nice simple explanation with charts to back up your points

[phil nw.]

Yes thanks C.

We are getting there slowly it seems,realisticaly the effects on our 500hPa pattern will likely be further on,based on the mean Zonal wind forecasts.

T240 shows the reversal down to 10hPa levels so we are getting close if that verifies.

Obviously a little too far out for current Trophospheric modelling to pick out complete vortex changes yet--apart of course from the Aluetian ridging,which i have just highlighted in the Mod.Disc.Thread.

Surely we can`t be far away from some consistently cold charts showing in the FI frames at least you would have thought.