Stratosphere Temperature Watch

[knocker]

Ben, I am of the thought that unless these warmings propagate far further down the stratosphere (which they are not forecast to do) then we will not see any benefit from them.

I obviously take what you say without reservation chiono but I'm afraid that won't stop me asking what is no doubt a stupid question. The 168 hour GFS shows a fair bit of warming at 10mb over Europe that doesn't propagate down to the the 30mb level. (see charts). Is there any connection between this ( the 10mb chart) and the quite strong build up of heights in the eastern atlantic?

[chionomaniac]

I obviously take what you say without reservation chiono but I'm afraid that won't stop me asking what is no doubt a stupid question. The 168 hour GFS shows a fair bit of warming at 10mb over Europe that doesn't propagate down to the the 30mb level. (see charts). Is there any connection between this ( the 10mb chart) and the quite strong build up of heights in the eastern atlantic?

Ws, the answer is yes, there is a strong correlation - but sometimes just looking at the cross sectional views of different levels of the vortex this can be difficult to see. It is far easier to see when one looks at a 3D animation of the whole vortex which can highlight the areas of greater vorticity, and how these translate up and down the whole vortex.

[knocker]

Ws, the answer is yes, there is a strong correlation - but sometimes just looking at the cross sectional views of different levels of the vortex this can be difficult to see. It is far easier to see when one looks at a 3D animation of the whole vortex which can highlight the areas of greater vorticity, and how these translate up and down the whole vortex.

Thanks very much for the answer and advice.

[beng]

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2011.gif

Seems to be descending for the moment. Should be clearer in a couple of days.

[karyo]

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2011.gif

Seems to be descending for the moment. Should be clearer in a couple of days.

Annoyingly though it has that column of cooler temperatures still underneath it!

Karyo

[picog]

Annoyingly though it has that column of cooler temperatures still underneath it!

Karyo

And, that column is getting cooler!

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

[bluearmy]

i assume todays necp 100hpa pressure chart is the strat equivalent of 'an outlier'.

[geoffw]

what you mean bluearmy?

[bluearmy]

what you mean bluearmy?

its out of step with its previous output, ecm output and doesnt reflcet the general ens trop output at that timeframe. therefore it looks very unsupported to me which is the definition of an outlier in ensemble terms.

[chionomaniac]

i assume todays necp 100hpa pressure chart is the strat equivalent of 'an outlier'.

I would say more likely uncertainty.

[geoffw]

what the weather impacts be from the outlier?

[chionomaniac]

its out of step with its previous output, ecm output and doesnt reflcet the general ens trop output at that timeframe. therefore it looks very unsupported to me which is the definition of an outlier in ensemble terms.

Just when I thought that the stratosphere was powering up and we are about to enter a period dominated by a strong polar vortex my ears have twitched at the latest output.

Firstly, let's look at the 100hPa level. Is the latest ECM output a one off or change in direction? Well being so close to the troposphere the output is less consistent than that further up the stratosphere and this should be borne in mind but I do not think this is an outlier - more a change in direction.

Looking at the output for Day 5 at 100 hPa we see good agreement for a mid Atlantic block extending over the western side of the UK. These charts are never going to give any amount of detail regarding exactly how west any cold air will come in this type of scenario.

Moving on to day 10 and can we get an idea of any pattern and do the GFS and ECM agree?

Well the pattern seen is for the mid Atlantic block to move east with the GFS showing signs of Scandi height rises as February nears, and the ECM block over the UK.

In these situations it is worth looking at other factors that could influence the position of the ridge. The MJO is set to reach a peak in phase 7 before declining. The non La Nina H500 anomaly for February is the closest suggesting that height rises could occur further east but not so for phase 8, nor La Nina phase 7-8. So confidence is low but this cannot be ruled out.

Moving higher up the stratosphere the first thing to note at the 10 hPa level is the increasing strength and symmetry of the polar vortex. However, do note that the vortex is more Pacifically positioned which favours the Atlantic side for blocking.

And finally ( it is always good to leave the interesting bit til the end) are we seeing signs of another warming at the 10hPa level ( possibly following a NA MT event)? It certainly looks like it! Perhaps we may have more to shout about come February.

I'll be watching.

Edited January 18, 2011 by chionomaniac

[beng]

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_JFM_NH_2011.gif

Yes you can just see the first sign of the high level warming here - I guess we'll have to wait and see how big it'll be, but if I was to guess, I'd say it will be stronger than the last as from what I've seen in previous years the events frequently escalate to a crescendo and then peak.

[MR EXTREMES]

very intresting SO BFTP LRF or should i say febuary idears!!!

just maybe fingers crossed.

[chionomaniac]

The 100 and 10 hPa trends continuing this morning.

[bluearmy]

The 100 and 10 hPa trends continuing this morning.

as does the ncep with the trough dug into the uk from the northwest and a sharp ridge to our east. so the two outputs not in agreement with the troughing from the nw though the transfering east of the block is supported.

[Glacier Point]

So the question was asked about downwellng westerly QBO-induced wave in the atmosphere....

Bit of a photoshop job splicing yearly plots, but we can see here how the westerly winds have increased in strength from the upper stratosphere and propagated downwards. They now are impacting the 200hPa and 500hPa layers, hence polar vortex and lowering heights.

These waves are complex beasts but the general periodicity is for 3 months of upwelling (easterly downwelling) favouring high latitude blocking and 3 months downwelling westerlies destructively interferring with blocking as it interacts with the upper troposphere. The timing of this has been pretty much in line with projections. The next wave should be instigated by the change in the QBO late summer / autumn.

Edited January 19, 2011 by Glacier Point

[bluearmy]

So the question was asked about downwellng westerly QBO-induced wave in the atmosphere....

Bit of a photoshop job splicing yearly plots, but we can see here how the westerly winds have increased in strength from the upper stratosphere and propagated downwards. They now are impacting the 200hPa and 500hPa layers, hence polar vortex and lowering heights.

These waves are complex beasts but the general periodicity is for 3 months of upwelling (easterly downwelling) favouring high latitude blocking and 3 months downwelling westerlies destructively interferring with blocking as it interacts with the upper troposphere. The timing of this has been pretty much in line with projections. The next wave should be instigated by the change in the QBO late summer / autumn.

which means it was aleways coming and the strat warming did nothing to hasten its influence in the trop by forcing it down faster.

[knocker]

I will have to return to GPs interesting post after much more thought as I find the the role of the QBO in coupling processes difficult to get my head around. So for the moment..........

Given the current and forecast direction of the AO and NAO there would appear to be much less chance of a return to N. blocking and thus a return to any severe weather from the east. Certainly in the near future. Is this a fair assumtion taking into account it's models we are talking here that don't necessarily take into account other influences such as may occur in the stratosphere? Or could stratospheric events, out of the blue, so to speak, alter the picture relatively quickly?

Current AO and NAO and blocking. The color scheme denotes the strength of the blocked flow as determined from the 500 hPa geopotential height gradient measured from the blocking ridge equatorward (denoted GHGS in blocking index definition).

Edited January 20, 2011 by weather ship

[chionomaniac]

I will have to return to GPs interesting post after much more thought as I find the the role of the QBO in coupling processes difficult to get my head around. So for the moment..........

Given the current and forecast direction of the AO and NAO there would appear to be much less chance of a return to N. blocking and thus a return to any severe weather from the east. Certainly in the near future. Is this a fair assumtion taking into account it's models we are talking here that don't necessarily take into account other influences such as may occur in the stratosphere? Or could stratospheric events, out of the blue, so to speak, alter the picture relatively quickly?

Current AO and NAO and blocking. The color scheme denotes the strength of the blocked flow as determined from the 500 hPa geopotential height gradient measured from the blocking ridge equatorward (denoted GHGS in blocking index definition).

I don't think that any stratospheric event will come so quickly out of the blue that we will not have sufficient prior warning. Even SSW's start from a forecast warming that will eventually create a displacement or split - and this takes time.

The present stratospheric conditions are helping contribute to the AO , but there are certainly changes again afoot in the upper stratosphere which need monitoring and could lead to changes later in Feb.

Edited January 20, 2011 by chionomaniac

[Swave Snow]

http://www.cpc.ncep....JFM_NH_2011.gif

Does this now look like massive cooling is taking place or am I misreading this?

[chionomaniac]

http://www.cpc.ncep....JFM_NH_2011.gif

Does this now look like massive cooling is taking place or am I misreading this?

That shows the upper stratospheric warmings that have occurred ( the yellows and orange) but these have failed to lower to the troposphere. Obviously this chart does not show the latitude and longitude of warmer and cooler zones - all important when looking at the stratosphere.

[chionomaniac]

The latest warming is still forecast to occur. Quite often we will see one warming followed by another that is stronger than the previous. This looks to be the case this time. The previous warming never propagated lower than the 10 hPa level. If any stratospheric warming is to interact with tropospheric patterns then we need to see either propagation of warmth to lower stratospheric levels or severe uppere vortex disruptions which can also influence the position and strength of the vortex lower down.

Interestingly with the latest warming the vortex strength of the upper vortex at 1hPa is set to reduce dramatically, from around 80m/s to below 40m/s. The warming at the 10 hPa level is so far forecast to be greater than the previous as can be seen here.

There are early signs that the warming is forecast to reach the 30hpa level.

So good news there, but still only a longe range forecast.

Will this forecast warming be enough to disrupt the ever strengthening and more centrally placed polar vortex? Well, I think possibly. However it is very important not to suggest in the model output thread that we are already experiencing a warming or that we are soon to see a SSW. The first is not true and the second we just don't know. AN SSW is unlikely as there is only ever been one recording of a SSW in a solar min and -QBO winter.

Looking at the 100hPa level the signal is mixed to what happens with the limpet high around the UK. The forecasts suggest that this will still be close to the UK. The 10% chance of the high travelling east has faded.

c

[Guest mycroft]

Chionomaniac said..

AN SSW is unlikely as there is only ever been one recording of a SSW in a solar min and -QBO winter.

do you know what winter that was?

[chionomaniac]

Chionomaniac said..

AN SSW is unlikely as there is only ever been one recording of a SSW in a solar min and -QBO winter.

do you know what winter that was?

Yes. You will remember it well. January 2009 leading to the early Feb easterly.