In Depth Model Discussion, Analysis and Summaries

[shotski]

Glacier Point and Steve Murr are probably the best based on teleconnections. Blast and Roger usually combine a forecast each year. They were all on the ball last winter.

But off the mark this summer

[ICETAB]

Glacier Point and Steve Murr are probably the best based on teleconnections. Blast and Roger usually combine a forecast each year. They were all on the ball last winter.

I was thinking of Glacier Point. Steve Murr is of course a legend in his own lunchtime. So GP has not been posting this summer/autum then? I'd like to get his view on the situation for the coming winter.

[summer blizzard]

I was thinking of Glacier Point. Steve Murr is of course a legend in his own lunchtime. So GP has not been posting this summer/autum then? I'd like to get his view on the situation for the coming winter.

A page or two back he posted his thoughts for the next couple of months.

[M1JWR]

I agree, solar activity has been generaly low to very low with only spikes of high activity.

If activity continued like it has been the last couple of days then I would be more aprenhensive

about a -AO and NAO during the winter but I do not think this will be the case.

I can see no reason why we will not see further northern blocking and a - NAO this winter

although I myself think it will be more east based with a much greater chance of

continental Arctic air by way of Scandi and Siberian high with the colder SST,S aiding in

lower pressure taking a more southerly track with some classic easterly synoptic set ups.

I am not totally convinced about the solar output and the weather, i am no weather expert

but i am a ham radio operator and back in 1981 i was a cb radio operator, 1981 was around

about the peak of solar cycle 21, it was a big one, and the skip as we called it was massive,

you couldent hear your mate from down the street for american truckers.

You all go on about low solar output and cold weather, why i mention 1981, it was the coldest

winter i can ever remember, and yes, at near enough the peak of the biggest solar cycle i can

remember

the weather is gonna do what its gonna do

[Rollo]

I am not totally convinced about the solar output and the weather, i am no weather expert

but i am a ham radio operator and back in 1981 i was a cb radio operator, 1981 was around

about the peak of solar cycle 21, it was a big one, and the skip as we called it was massive,

you couldent hear your mate from down the street for american truckers.

You all go on about low solar output and cold weather, why i mention 1981, it was the coldest

winter i can ever remember, and yes, at near enough the peak of the biggest solar cycle i can

remember

the weather is gonna do what its gonna do

Whilst true that the winter of 81' and particularly the December of that winter was severe,there are many reasons other than the solar cycle to take into account,you are quite right to say the weather will do what the weather will do but science has only made the strides it has when people start delving into facts and figures that did not used to be available.

[BLAST FROM THE PAST]

I am not totally convinced about the solar output and the weather, i am no weather expert

but i am a ham radio operator and back in 1981 i was a cb radio operator, 1981 was around

about the peak of solar cycle 21, it was a big one, and the skip as we called it was massive,

you couldent hear your mate from down the street for american truckers.

You all go on about low solar output and cold weather, why i mention 1981, it was the coldest

winter i can ever remember, and yes, at near enough the peak of the biggest solar cycle i can

remember

the weather is gonna do what its gonna do

Think hemispherically NOT locally. The general set up oceanic and jetstream is being affected cyclically. Very different times and ahead.

BFTP

[summer blizzard]

John Holmes - copied into here as more relevant thread..

am afraid I find that the accuracy of the MJO forecasts is mostly fairly low but it may be me reading more into it than I should.

The AO prediction and the NAO and PDO all seem more accurate which is odd or so it seems to me?

any thoughts ch, sb or maybe GP?

The general prognosis i would trust because we have seen GLAMM levels rising over the past month or two, that said the combination of a strengthening La Nina and -QBO should override whatever is causing the increased GLAMM which should in turn mean a return to a low amplitude MJO and collapse in GLAMM readings, possibly within the next month.

What this means for the weather is that we will likely see the NW/SE split with an active Atlantic but high pressure close to the south east for a while although with the Polar Vortex strengthening, some of these lows may make it east of the UK as topplers.

Perhaps the most interesting thing in my opinion is that once levels fall again, we may see the AO tank with something a lot more wintry for November.

[johnholmes]

John Holmes - copied into here as more relevant thread..

am afraid I find that the accuracy of the MJO forecasts is mostly fairly low but it may be me reading more into it than I should.

The AO prediction and the NAO and PDO all seem more accurate which is odd or so it seems to me?

any thoughts ch, sb or maybe GP?

The general prognosis i would trust because we have seen GLAMM levels rising over the past month or two, that said the combination of a strengthening La Nina and -QBO should override whatever is causing the increased GLAMM which should in turn mean a return to a low amplitude MJO and collapse in GLAMM readings, possibly within the next month.

What this means for the weather is that we will likely see the NW/SE split with an active Atlantic but high pressure close to the south east for a while although with the Polar Vortex strengthening, some of these lows may make it east of the UK as topplers.

Perhaps the most interesting thing in my opinion is that once levels fall again, we may see the AO tank with something a lot more wintry for November.

thanks for the comments

[Glacier Point]

John Holmes - copied into here as more relevant thread..

am afraid I find that the accuracy of the MJO forecasts is mostly fairly low but it may be me reading more into it than I should.

The AO prediction and the NAO and PDO all seem more accurate which is odd or so it seems to me?

any thoughts ch, sb or maybe GP?

The general prognosis i would trust because we have seen GLAMM levels rising over the past month or two, that said the combination of a strengthening La Nina and -QBO should override whatever is causing the increased GLAMM which should in turn mean a return to a low amplitude MJO and collapse in GLAMM readings, possibly within the next month.

What this means for the weather is that we will likely see the NW/SE split with an active Atlantic but high pressure close to the south east for a while although with the Polar Vortex strengthening, some of these lows may make it east of the UK as topplers.

Perhaps the most interesting thing in my opinion is that once levels fall again, we may see the AO tank with something a lot more wintry for November.

It's interesting to note that the upward trend in AAM happend before the current MJO wave began to develop, possibly the two facets of the atmosphere-ocean dynamical process responding to the same lead ? We have had three strong +MT events now, all driving the GWO into a high angular momentum base state. Not sure we can confidently count on AAM crashing anytime soon. October's GLAAM value should be unprecedented in the 53 yr time series in terms of going from a negative value in September through to a positive value in October. Our closest analogue in this respect is 1995 with a disconnect between ENSO and the atmospheric circulation, which may well last until December. The QBO is also interesting. Lastest daily values actually have it weakening at 30 hPa (less easterly), with the lower stratospheric levels still showing a westerly wind. All of which means that ENSO forecasts for the winter mean squat right now

[summer blizzard]

It's interesting to note that the upward trend in AAM happend before the current MJO wave began to develop, possibly the two facets of the atmosphere-ocean dynamical process responding to the same lead ? We have had three strong +MT events now, all driving the GWO into a high angular momentum base state. Not sure we can confidently count on AAM crashing anytime soon. October's GLAAM value should be unprecedented in the 53 yr time series in terms of going from a negative value in September through to a positive value in October. Our closest analogue in this respect is 1995 with a disconnect between ENSO and the atmospheric circulation, which may well last until December. The QBO is also interesting. Lastest daily values actually have it weakening at 30 hPa (less easterly), with the lower stratospheric levels still showing a westerly wind. All of which means that ENSO forecasts for the winter mean squat right now

It's interesting to note that the upward trend in AAM happend before the current MJO wave began to develop, possibly the two facets of the atmosphere-ocean dynamical process responding to the same lead ? We have had three strong +MT events now, all driving the GWO into a high angular momentum base state. Not sure we can confidently count on AAM crashing anytime soon. October's GLAAM value should be unprecedented in the 53 yr time series in terms of going from a negative value in September through to a positive value in October. Our closest analogue in this respect is 1995 with a disconnect between ENSO and the atmospheric circulation, which may well last until December. The QBO is also interesting. Lastest daily values actually have it weakening at 30 hPa (less easterly), with the lower stratospheric levels still showing a westerly wind. All of which means that ENSO forecasts for the winter mean squat right now

Interesting, why do you think the QBO could be becoming less easterly? Recent years have seen a clear strengthening.

[scotty_boy_winter]

I agree 100 per cent with GP. Looking at the current evidence it's VERY clear it's becoming less easterly, previous years mean ABSOLUTELY nothing. It Is very clear it's becoming less westerley. As much of a cold ramper I am, science tells me this yeR will be a lot milder. End of

Interesting, why do you think the QBO could be becoming less easterly? Recent years have seen a clear strengthening.

Less easterly I mean!

I agree 100 per cent with GP. Looking at the current evidence it's VERY clear it's becoming less easterly, previous years mean ABSOLUTELY nothing. It Is very clear it's becoming less westerley. As much of a cold ramper I am, science tells me this yeR will be a lot milder. End of

[geoffw]

as far as im aware gp didnt mention whether winter would be mild or cold?

[Snowmad79]

Our closest analogue in this respect is 1995 with a disconnect between ENSO and the atmospheric circulation, which may well last until December

If thats the case, then why would Noaa continue to say in their weekly updates that Atmospheric circulations are consistant with La nina ?

[beng]

GP - so if I understand your post, the 'atmospheric' conditions have switched in a very rapid way from la nina type patterns to an el nino type circulation? I think this might be good news for cold fans as the sub surface temps in the Pacific looked to have been cooling quite rapidly - meaning we could be moving to a moderate la nina, rather than a weak event. If I've understood your post, then the change in atmospheric patterns might put a stop to that and cap the enso as weak la nina - or warmer?

[summer blizzard]

GP - so if I understand your post, the 'atmospheric' conditions have switched in a very rapid way from la nina type patterns to an el nino type circulation? I think this might be good news for cold fans as the sub surface temps in the Pacific looked to have been cooling quite rapidly - meaning we could be moving to a moderate la nina, rather than a weak event. If I've understood your post, then the change in atmospheric patterns might put a stop to that and cap the enso as weak la nina - or warmer?

GP - so if I understand your post, the 'atmospheric' conditions have switched in a very rapid way from la nina type patterns to an el nino type circulation? I think this might be good news for cold fans as the sub surface temps in the Pacific looked to have been cooling quite rapidly - meaning we could be moving to a moderate la nina, rather than a weak event. If I've understood your post, then the change in atmospheric patterns might put a stop to that and cap the enso as weak la nina - or warmer?

Any westerly element to the QBO would actually bring up the sub surface water and lead to a stronger La Nina than the current weak one (September MEI value was a weak La Nina -0.7). That said, GLAMM levels would be higher with higher amplitude MJO waves which could be good in the right phase.

Would a continuation of this pattern lead to stratospheric warming?

[ribster]

I agree 100 per cent with GP. Looking at the current evidence it's VERY clear it's becoming less easterly, previous years mean ABSOLUTELY nothing. It Is very clear it's becoming less westerley. As much of a cold ramper I am, science tells me this yeR will be a lot milder. End of

I would be very interested in the evidence and science to which you refer, not that science always has all the answers anyway. More to the point, I was under the impression that the QBO and lack of or abundant stratospheric warming isn't the be all and end all, there are many factors at play, some of which I don't believe science has a handle on yet.

In addition, I assume that leading up to the summer, the 'science' indicated a shades of 76 summer, but it was nothing of the sort. That isn't a dig at GP, whom I have enormous respect for, but the 'scientific situation' clearly changed to deliver us something very different.

Edited October 9, 2011 by ribster

[Met4Cast]

I'm trying to get to grips with the QBO, am I right in saying that a -QBO usually brings colder weather through January and February? And that last winter, a positive QBO combined with a strenghtening La Nina led to a poor second half to winter (snow wise) last winter?

Also, is a Westerly QBO positive and Easterly QBO negative? How do these effect possible winter weather? Thanks for your help.

[chionomaniac]

I'm trying to get to grips with the QBO, am I right in saying that a -QBO usually brings colder weather through January and February? And that last winter, a positive QBO combined with a strenghtening La Nina led to a poor second half to winter (snow wise) last winter?

Also, is a Westerly QBO positive and Easterly QBO negative? How do these effect possible winter weather? Thanks for your help.

The quasi-biennial oscillation (QBO) is a tropical stratospheric wind that travels easterly then westerly over a period for the full cycle of just over 2 years. You are right in suggesting that the westerly winds are known as positive and the easterly winds are negative. The pulse of westerly or easterly winds tend to commence in the upper regions of the tropical stratosphere and push downwards towards the troposphere. This can leave us in a state where the upper winds in the tropical stratosphere are westerly and the lower regions are easterly or vice versa depending on what stage of the QBO we are in. Sometimes these winds can push through and affect the polar stratosphere and other times they do not. The general reading for the state of the QBO mean winds is normally taken at the 30 hPA level.

Generally, it is thought that the stratospheric vortex polar is increased in a westerly QBO regime and decreased in an easterly regime. However the exact timing and positioning of these winds descending the stratosphere is going to have a big influence on polar regions.

Then we also need to take into consideration the Brewer Dobson circulation (BDC). This is the mechanism that transfers ozone from the tropical stratosphere to the polar stratosphere. Labitzke has shown that this mechanism is influenced by the state of the QBO and the amount of solar flux present. An easterly QBO in solar minimum conditions increases the BDC as does a westerly QBO in solar maximum conditions.

Increased polar ozone will lead to a warmer polar stratosphere and a reduced thermal gradient between the polar and tropical stratosphere. This in turn will lead to a reduced polar vortex and a more disrupted tropospheric jet stream.

Then we need to add in to the mix the ENSO state and how this interacts with the state of the QBO and tropical stratosphere and we begin to realise how complex all this is and that to just say a negative QBO is favourable for winter is just a little bit too simplistic!

[johnholmes]

!

thanks as always ch for making a complex, very complex subject, more understandable.

[Met4Cast]

Thanks I appreciate your reply, I think I understand it a little more now could you possibly link me to the QBO forecast? If there is such a thing. Cheers. I really do appreciate your efforts.

The quasi-biennial oscillation (QBO) is a tropical stratospheric wind that travels easterly then westerly over a period for the full cycle of just over 2 years. You are right in suggesting that the westerly winds are known as positive and the easterly winds are negative. The pulse of westerly or easterly winds tend to commence in the upper regions of the tropical stratosphere and push downwards towards the troposphere. This can leave us in a state where the upper winds in the tropical stratosphere are westerly and the lower regions are easterly or vice versa depending on what stage of the QBO we are in. Sometimes these winds can push through and affect the polar stratosphere and other times they do not. The general reading for the state of the QBO mean winds is normally taken at the 30 hPA level.

Generally, it is thought that the stratospheric vortex polar is increased in a westerly QBO regime and decreased in an easterly regime. However the exact timing and positioning of these winds descending the stratosphere is going to have a big influence on polar regions.

Then we also need to take into consideration the Brewer Dobson circulation (BDC). This is the mechanism that transfers ozone from the tropical stratosphere to the polar stratosphere. Labitzke has shown that this mechanism is influenced by the state of the QBO and the amount of solar flux present. An easterly QBO in solar minimum conditions increases the BDC as does a westerly QBO in solar maximum conditions.

Increased polar ozone will lead to a warmer polar stratosphere and a reduced thermal gradient between the polar and tropical stratosphere. This in turn will lead to a reduced polar vortex and a more disrupted tropospheric jet stream.

Then we need to add in to the mix the ENSO state and how this interacts with the state of the QBO and tropical stratosphere and we begin to realise how complex all this is and that to just say a negative QBO is favourable for winter is just a little bit too simplistic!

[chionomaniac]

Thanks I appreciate your reply, I think I understand it a little more now could you possibly link me to the QBO forecast? If there is such a thing. Cheers. I really do appreciate your efforts.

There isn't really a forecast as such, but data can be find at a number of sites.

http://www.geo.fu-be.../qbo/index.html

http://www.cdc.noaa....lation/qbo.data

http://iridl.ldeo.columbia.edu/maproom/.Global/.Atm_Circulation/QBO.html

Of note is that even though we are heralding a negative QBO regime for this winter, it will be the westerlies that will be being flushed through at the lower stratospheric and upper tropospheric level in the tropics as can be demonstrated below:

How this influences latitudes further north is what I am left wondering. Will increased tropical westerlies invigorate the MJO and is this the reason why there has been an increase in GLAAM?

Edited October 10, 2011 by chionomaniac

[chionomaniac]

thanks as always ch for making a complex, very complex subject, more understandable.

Thanks

[Isolated Frost]

Yes, thanks for this ch - very interesting and helpful. Keep up the good work!

[ribster]

The quasi-biennial oscillation (QBO) is a tropical stratospheric wind that travels easterly then westerly over a period for the full cycle of just over 2 years. You are right in suggesting that the westerly winds are known as positive and the easterly winds are negative. The pulse of westerly or easterly winds tend to commence in the upper regions of the tropical stratosphere and push downwards towards the troposphere. This can leave us in a state where the upper winds in the tropical stratosphere are westerly and the lower regions are easterly or vice versa depending on what stage of the QBO we are in. Sometimes these winds can push through and affect the polar stratosphere and other times they do not. The general reading for the state of the QBO mean winds is normally taken at the 30 hPA level.

Generally, it is thought that the stratospheric vortex polar is increased in a westerly QBO regime and decreased in an easterly regime. However the exact timing and positioning of these winds descending the stratosphere is going to have a big influence on polar regions.

Then we also need to take into consideration the Brewer Dobson circulation (BDC). This is the mechanism that transfers ozone from the tropical stratosphere to the polar stratosphere. Labitzke has shown that this mechanism is influenced by the state of the QBO and the amount of solar flux present. An easterly QBO in solar minimum conditions increases the BDC as does a westerly QBO in solar maximum conditions.

Increased polar ozone will lead to a warmer polar stratosphere and a reduced thermal gradient between the polar and tropical stratosphere. This in turn will lead to a reduced polar vortex and a more disrupted tropospheric jet stream.

Then we need to add in to the mix the ENSO state and how this interacts with the state of the QBO and tropical stratosphere and we begin to realise how complex all this is and that to just say a negative QBO is favourable for winter is just a little bit too simplistic!

Excellent post, which rather puts the post I was referring to in context. Thanks.

[skifreak]

Anyone got any thoughts on this, it's a graph of averaged QBO values over JFM for the years concerned vs a somewhat subjective Scottish Snowsports Season Quality Index on a scale of (0) to (5):

It would seem to suggest that the chances of a good season are enhanced when the QBO phase is well established (regardless of whether it is Easterly or Westerly), but that a value above -5 and below 5 (I assume this range suggests phase transition?) means the balance of probability is for a poor Scottish Snowsports Season?

The 1 season ranked at 5 with a +2.3 QBO value is the freakshow that was 1979, where the mid mountain Coire Cas Ski Tow on CairnGorm Mountain (base elevation is 2500ft) continued daily operations in to June.

One further observation of the QBO and Scottish Skiing is that it seems to have been in phase with our winters since 2006, Westerly QBO's have brought an earlier finish to the season (no later than last week of April, mostly mid April) with summer like Aprils, while negative QBO phases have brought later finishes to the season (at least into May, 2010 into June) with some fantastic mid-winter conditions in March and April.

[edit]

Just to add to the above, the 2 appalling seasons with very negative QBO values were 1982 and 1992. It just happens that 1982, 1992 and 2002 where all poor if not horrific seasons, I gather 1972 was nothing to write home about either.....

Edited October 12, 2011 by skifreak