Stratosphere Temperature Watch

[chionomaniac]

Hi - I expect you are glad to be home!? Hope your injury recovers asap

A canadian warming could sow the seed nicely for blocking potential shifting eastwards as the winter goes on, in line with growing opportunities for a full-on SSW with ozone distribution and amounts this year looking complissant for that - as GP has mentioned recently.

Whatever happens, so nice to be seeing upticks in the stratosphere line graphs predicted to perhaps start the winter this year when we are so used to seeing much longer downticks instead more usually at this time.

Yes, T thanks. Let's hope we have something worth watching this year as well!

Here is a comparison to last year and this so far - temps up and zonal winds down.

Last year

This year

c

[Glacier Point]

It might be worth noting that mountain torques have gone from nearly -4 SD to +3 SD in a relatively short period. This may well be manifesting itself in terms of the stratospheric profile.

[weatherjunkie]

It might be worth noting that mountain torques have gone from nearly -4 SD to +3 SD in a relatively short period. This may well be manifesting itself in terms of the stratospheric profile.

So there's potential to see more warming?

[cooling climate]

It might be worth noting that mountain torques have gone from nearly -4 SD to +3 SD in a relatively short period. This may well be manifesting itself in terms of the stratospheric profile.

The models are forcasting a large ridge over northwest America in about 6-8 days time and I feel

quite confident this is what the ECM stratosphere models are seeing.

This should cause the mountain torques to spike.

Edited November 25, 2009 by cooling climate

[chionomaniac]

We have wondered entering this winter whether we would have a weaker polar vortex as a result of an easterly QBO and enhanced Brewer-Dobson circulation transporting more ozone to high NH latitudes and already there are signs that this is the case. The stratospheric vortex has been very much under strength this autumn as a result of warmer temperatures above the North pole and colder stratospheric temperatures equatorwards.

This has resulted in significant negative zonal wind anomalies in the stratosphere during this month.

Now, whilst these may reduce in intensity as they propagate down to the troposphere, they may still be strong enough to create an influence and encourage NH blocking. Here are the ECM forecasts showing the propagation of these anomalies down to the troposphere:

T+00

T+120

The area of negative zonal winds(the blue zone) seems to intensify as it propagates down to the troposphere and migrate southwards where they will then lose intensity.

The 100hpa forecast shows how the vortex leaves an area for ridging to possibly occur to our north with the main area of lower stratospheric vortex residing over north Siberia.

This to me is encouraging and supportive of the Northern blocking seen by the models and AO and NAO forecasts. Could the stratospheric signal override the EL Nino signal? It certainly can't be ruled out.

Looking further afield we are still seeing that the stratospheric vortex is still having trouble becoming established over the north pole.

Here are the 10 hPa vortex forecasts which have been preceded by another minor warming

At T+120 the vortex looks like it may be gaining in strength over the North Pole.

However by T+240 the minor warming has caused an Alaskan pressure build displacing the vortex into a sausage shape.

All these disruptions to the vortex can have tropospheric impacts further down the line as hopefully early December will show from Novembers stratospheric conditions.

Further warmings are likely to occur. However I am keeping my eye on a dramatic forecast drop in zonal winds right at the top of the stratosphere (1hPa level) to see if this possibly propagates lower down the stratosphere - that could be a significant event.

c

[Guest North Sea Snow Convection]

This to me is encouraging and supportive of the Northern blocking seen by the models and AO and NAO forecasts. Could the stratospheric signal override the EL Nino signal? It certainly can't be ruled out.

Looking further afield we are still seeing that the stratospheric vortex is still having trouble becoming established over the north pole.

Here are the 10 hPa vortex forecasts which have been preceded by another minor warming

At T+120 the vortex looks like it may be gaining in strength over the North Pole.

However by T+240 the minor warming has caused an Alaskan pressure build displacing the vortex into a sausage shape.

All these disruptions to the vortex can have tropospheric impacts further down the line as hopefully early December will show from Novembers stratospheric conditions.

Further warmings are likely to occur. However I am keeping my eye on a dramatic forecast drop in zonal winds right at the top of the stratosphere (1hPa level) to see if this possibly propagates lower down the stratosphere - that could be a significant event.

c

An especially interesting update

Yes, plenty of supportive reasons for further warming events to occur along with continued disruption to the polar vortex at a time when it would usually be becoming the dominant winter factor.

Such a drop in zonal winds as you suggest would be a real coup if it happened to propagate. The current short dip in 10mb temps might actually help to shuffle the deck in that respect and push any potential negative zonal winds towards the surface. This, it if happened successfully, would suggest that the atlantic lows should really back off. along with classic undercut of blockiing. Cold polar air would have an enhanced chance of getting right down to mid latitudes with the whole of the UK on the polar side of the jet stream. Recipe for snow methinks

Could the ammunition against el nino be growing at just the right time!?

But that is enough ramping for one post - winter must have arrived!

Edited November 27, 2009 by North Sea Snow Convection

[chionomaniac]

An especially interesting update

Yes, plenty of supportive reasons for further warming events to occur along with continued disruption to the polar vortex at a time when it would usually be becoming the dominant winter factor.

Such a drop in zonal winds as you suggest would be a real coup if it happened, as it would suggest that the atlantic lows should really back off. along with classic undercut of blockiing. Cold polar air would have an enhanced chance of getting right down to mid latitudes with the whole of the UK on the polar side of the jet stream. Recipe for snow methinks

Could the ammunition against el nino be growing at just the right time!?

But that is enough ramping for one post - winter must have arrived!

Tamara, look where the strongest tropospheric positive zonal mean winds are on the second and third charts. They are around 30-40ºN. I would love to see where they were at the same corresponding time last year but I suspect that we are further south this year. I also suspect that any southerly track of the jet stream may also be linked to the enhanced BDC but I am not sure. GP?

[Guest North Sea Snow Convection]

Tamara, look where the strongest tropospheric positive zonal mean winds are on the second and third charts. They are around 30-40ºN. I would love to see where they were at the same corresponding time last year but I suspect that we are further south this year. I also suspect that any southerly track of the jet stream may also be linked to the enhanced BDC but I am not sure. GP?

I do think we are. We don't have a westerly QBO fighting against us this year, and remember we still saw that period of modest blocking near Iceland through the festive period/early Jan last year - so what even better price this time?

Regarding your BDC point, not sure either, but from the point of view that this aligns itself with better warming opportunities (and hence better northern blocking potential) that it can only help regarding the jet stream trajectory. Along of course with a not too bad atlantic SST arrangement that might help a -NAO, especially as events in the pacific push the dateline.

Edited November 27, 2009 by North Sea Snow Convection

[chionomaniac]

I do think we are. We don't have a westerly QBO fighting against us this year, and remember we still saw that period of modest blocking near Iceland through the festive period/early Jan last year - so what even better price this time?

Regarding your BDC point, not sure either, but from the point of view that this aligns itself with better warming opportunities (and hence better northern blocking potential) that it can only help regarding the jet stream trajectory. Along of course with a not too bad atlantic SST arrangement that might help a -NAO, especially as events in the pacific push the dateline.

One of the things that I find interesting is the thought of Atlantic blocking early on in the winter. Knowing that Atlantic blocking is a precursor to a displacement type SSW and that the stratosphere is ripe for a SSW this year, I would be extremely encouraged that a SSW could occur at a time when its effects would be felt in the heart of winter. And with a easterly QBO, and no La Nina, perhaps also a better chance of blocking following the SSW. All of this is theory but this is why I think we will have a colder than average Jan with 1987 being a similar comparison year.

[BLAST FROM THE PAST]

I also suspect that any southerly track of the jet stream may also be linked to the enhanced BDC but I am not sure. GP?

C

If I may be so cheeky to say that sloar and lunar phasing predicts a southerly tracking jet as it has done for 2+ years? That is my view anyway and thus this has direct influence on BDO QBO etc etc

[cooling climate]

Just wondering if anybody else is experiencing problems logging onto the ECM

stratosphere site.

[chionomaniac]

Just wondering if anybody else is experiencing problems logging onto the ECM

stratosphere site.

Yes and for over 24 hours now.

[Guest North Sea Snow Convection]

Just wondering if anybody else is experiencing problems logging onto the ECM

stratosphere site.

Yes ditto - and just mentioned that on the model thread

[chionomaniac]

With the Berlin site down at the moment it is very difficult to get a full picture of the stratosphere. This is a shame because it would be quite useful to see how the negative zonal wind anomalies are progressing down to the troposphere. Fingers crossed for tomorrow.

There is another bout of warming projected at the 10 hPa level probably following increased wave number 1 planetary wave activity (which has been particularly active during November)

These warmings which are moderate in nature have tended to follow the same pattern -building in eastern Siberia. It will be interesting to see if this one is preceded by an Asian Mountain Torque event. There tends to be a slight delay between any warming and any effect on the position or strength of the vortex. This was most obvious during last year's MMW when the vortex split a good few days after the warming. In this case the vortex looks to get slightly displaced from the pole with perhaps slight splitting lower down.

For those who are wondering how normal this seasons warmer stratosphere is compared to other years it is worth looking at graphical comparisons. Here we see at the 30 hPa level that the stratosphere is as warm as it has ever been recorded for this time of year.

The net vortex strength has increased recently but is still running well below average:

And I bet it is about to take another hit within the next fortnight.

c

Edited November 29, 2009 by chionomaniac

[karyo]

With the Berlin site down at the moment it is very difficult to get a full picture of the stratosphere. This is a shame because it would be quite useful to see how the negative zonal wind anomalies are progressing down to the troposphere. Fingers crossed for tomorrow.

c

The Berlin site has updated at long last! http://strat-www.met.fu-berlin.de/cgi-bin/times?plot=temps&alert=1

It shows the first below average spell of the season but thankfully it doesn't last long! A rise then brings us just above average but this rise is not as pronounced as it looked a few days ago.

Karyo

[cooling climate]

The Berlin site has updated at long last! http://strat-www.met...t=temps&alert=1

It shows the first below average spell of the season but thankfully it doesn't last long! A rise then brings us just above average but this rise is not as pronounced as it looked a few days ago.

Karyo

It looks like a heatwave is forcast to take place at the 1pa level. This almost certainly

relates to a wave breaking event do to the very large ridge over the gulf of Alaska that

will pump warm subtropical air into the system.

Edited November 30, 2009 by cooling climate

[chionomaniac]

It looks like a heatwave is forcast to take place at the 1pa level. This almost certainly

relates to a wave breaking event do to the very large ridge over the gulf of Alaska that

will pump warm subtropical air into the system.

I don't really know what to make of the forecast warming at the 1 hPa level. The upper stratosphere is currently a lot colder than average. During last winter's MMW the temperature only rose by a small amount at the 1 hPa level. This was then followed by a dramatic cooling compared to other levels of the stratosphere.

[winterfreak]

I don't really know what to make of the forecast warming at the 1 hPa level. The upper stratosphere is currently a lot colder than average. During last winter's MMW the temperature only rose by a small amount at the 1 hPa level. This was then followed by a dramatic cooling compared to other levels of the stratosphere.

Hi there, new member to the forum and a bit clueless. Could you please explain your comment above, in laymans, so an eejit like me can understand a little better what that means with regards to winter!

I'm trying to learn a little at a time you see.

Regards, WF.

[chionomaniac]

Hi there, new member to the forum and a bit clueless. Could you please explain your comment above, in laymans, so an eejit like me can understand a little better what that means with regards to winter!

I'm trying to learn a little at a time you see.

Regards, WF.

Hi WF.

I was suggesting that I did not know how significant a forecast warming at the very top of the stratosphere is.

If you read this thread from the start (you may have already done this) then hopefully you will have a better grasp. I would say that sometimes this subject can be quite complex because it requires an understanding of the troposphere first before working up to the stratosphere. If you have any further questions please don't hesitate to ask. Remember though that I am no expert in this regard, just an enthusiastic amateur!

Reading through the Netweather guides or asking questions in the learning area has helped me tremendously in the past.

c

[winterfreak]

Hi WF.

I was suggesting that I did not know how significant a forecast warming at the very top of the stratosphere is.

If you read this thread from the start (you may have already done this) then hopefully you will have a better grasp. I would say that sometimes this subject can be quite complex because it requires an understanding of the troposphere first before working up to the stratosphere. If you have any further questions please don't hesitate to ask. Remember though that I am no expert in this regard, just an enthusiastic amateur!

Reading through the Netweather guides or asking questions in the learning area has helped me tremendously in the past.

c

Many thanks for your reply. I had a read through the thread which does explain things. However, is a warmer stratosphere conducive to milder temps and a colder stratosphere to colder temps? This is the bit i can't get my head round..... as for sudden warmings and mid winter warmings....:lol:

WF

Edited November 30, 2009 by winterfreak

[chionomaniac]

Many thanks for your reply. I had a read through the thread which does explain things. However, is a warmer stratosphere conducive to milder temps and a colder stratosphere to colder temps? This is the bit i can't get my head round..... as for sudden warmings and mid winter warmings....:lol:

WF

As ever there are many variables which can affect the weather tropospherically, with the stratosphere being just one of them.

The general winter stratospheric rule is this: The colder the stratosphere becomes the stronger the stratospheric polar vortex(PV) becomes. The stronger the stratospheric PV, the stronger the tropospheric PV is. This leads to deeper low pressure over Greenland and a +AO which generally brings milder wetter conditions to the UK.

Any warming of the stratosphere can disrupt the PV and increase the chances of colder weather here.

Edited November 30, 2009 by chionomaniac

[johnholmes]

nicely explained there ch

[winterfreak]

As ever there are many variables which can affect the weather tropospherically, with the stratosphere being just one of them.

The general winter stratospheric rule is this: The colder the stratosphere becomes the stronger the stratospheric polar vortex(PV) becomes. The stronger the stratospheric PV, the stronger the tropospheric PV is. This leads to deeper low pressure over Greenland and a +AO which generally brings milder wetter conditions to the UK.

Any warming of the stratosphere can disrupt the PV and increase the chances of colder weather here.

Many thanks for the explanation there Ch, much appreciated and understood!

Edited November 30, 2009 by winterfreak

[brogdale]

Many thanks for your reply. I had a read through the thread which does explain things. However, is a warmer stratosphere conducive to milder temps and a colder stratosphere to colder temps? This is the bit i can't get my head round..... as for sudden warmings and mid winter warmings....

WF

Hi Chionomaniac

Long time no speak!

Just thought I'd ask if you're going to come and have a chat on the 'other forum' 'bout this. I've already kicked a thread off and posted some links to a CPC conference site with illustrated talks from the pros! I think you might enjoy them if you haven't already found them.

Well waddaya make of this early upper warming? And the EP veering poleward?

Good to be back in straty business eh?

Edited December 1, 2009 by brogdale

[chionomaniac]

Hi Chionomaniac

Long time no speak!

Just thought I'd ask if you're going to come and have a chat on the 'other forum' 'bout this. I've already kicked a thread off and posted some links to a CPC conference site with illustrated talks from the pros! I think you might enjoy them if you haven't already found them.

Well waddaya make of this early upper warming? And the EP veering poleward?

Good to be back in straty business eh?

Hi Brogdale

I hope you are well.

I have posted on the other site but have real difficulty posting up charts and links for some reason.

I am sad enough to have already read the links and viewed the presentations from the latest middle Atmosphere convention. I noticed that you had homed into the same presentations that had caught my eye!

c

Latest update.

The start to this stratospheric winter has already been very interesting with episodes of record breaking warmth over the North Pole contrasting with very cold stratospheric conditions over the equatorial stratosphere. This has led to the very disturbed stratospheric vortex conditions that we are seeing presently.

There appears to be another episode of warming about to occur that I have mentioned previously:

This may have been caused by an increase in recent wavenumber 1 activity which I mentioned a few days ago. This has been extremely prominent during November and activity can be viewed here.

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE1_MEAN_ALL_NH_2009.gif

It appears that another wave is in the process of propagating down the stratosphere.

However that is not what is grabbing my attention currently. What is grabbing my attention is a forecast split of the polar vortex from the base of the stratosphere/troposphere that is propagating upwards. It is this split vortex that is behind the interesting wave patterns that are being forecast by the tropospheric models. The last time we saw a split vortex like this was cough ahem back in January.

This split is being forecast by both the GFS and ECM but is more pronounced on the GFS and extends further up the stratosphere.

100 hPa level at T+240

30 hPa level at T+240

Could this just be?????

c