Stratosphere Temperature Watch 2012/2013

[chionomaniac]

it isn't so long ago that some thought the earth t'was flat crewe ! 

 

to be fair, despite our lack of resource, this is fairly 'cutting edge' stuff and as such, will not be embraced by all (yet)

It's not that cutting edge Nick - after all I started the first strat thread 5 years ago! I think that those who are yet to embrace are probably digging there heals in after refuting the importance of the strat those five years ago. ( Remember the SSW late Jan 2009 and the corresponding early Feb 2009 easterly?)

 

I tweeted this link earlier today but worth putting it up here as it shows how the SSW earlier this year was forecast and can be analysed with the new  GEOS-5 model: http://gmao.gsfc.nasa.gov/researchhighlights/SSW/

[Duane S.]

Completely agree that this is, by a country mile, THE most absorbing thread heading into and going through winter. I also agree with John that our actual understanding of this subject does not seem to increase proportionally by the amount of new stuff we learn year on year!

 

I think though that the fact stratosphere temperature forecasts are not subject to wild fluxuations unlike the troposphere means it has to be taken very seriously as a primary forecast tool for our weather, at least in terms of longwave patterns.

 

The real trick though is understanding the coupling between this (and indeed other potential primary drivers, i.e. ENSO) and our atmosphere / weather. Why do such seemingly similar states interact in completely different ways? What is driving what drives what? Why exactly do certain drivers get readily over-ridden / muted at times but become primary influencers at other times.

 

Nail that and huge steps forward in forecasting will occur overnight.

[lorenzo]

Oh go on then, let's have one of these graphs. anyone want to plot the line for the next 6 months

 

[Isolated Frost]

[Relativistic]

rrrr.png

Damn, was just about to do the same thing! Edited September 16, 2013 by 22nov10blast

[Don]

rrrr.png

 

Ha, that will give the mildies nightmares!

[Neilsouth]

rrrr.png

 

Is that predicted? Do we not want a warmer north pole with the colder air placed over siberia,north western europe?

[bobbydog]

Is that predicted? Do we not want a warmer north pole with the colder air placed over siberia,north western europe?

 

erm.... 47C plus whatever's 'off the scale' above the average, i'd say thats a warmer north pole!.... wouldn't you??

[Neilsouth]

I was looking at the December drop

[Snowy L]

Could anyone help in explaining what happened to the polar vortex in 2010 to cause such a cold and blocked start to the winter?

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/10mb9065_2010.gif

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/70mb9065_2010.gif

 

From what I can see there was nothing too out of the ordinary both higher and lower in the stratosphere. There was a small warming at 10hpa at the start of November and at the start of December, with nothing unusual happening lower down. Did this small warming delay the formation of the vortex and give us a cold November/December? Or did nothing happen to the vortex and the cold weather caused by something else?

[Suburban Streamer]

Is that predicted? Do we not want a warmer north pole with the colder air placed over siberia,north western europe?

 

no but its what we would all like to see

 

Could anyone help in explaining what happened to the polar vortex in 2010 to cause such a cold and blocked start to the winter?

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/10mb9065_2010.gif

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/70mb9065_2010.gif

 

From what I can see there was nothing too out of the ordinary both higher and lower in the stratosphere. There was a small warming at 10hpa at the start of November and at the start of December, with nothing unusual happening lower down. Did this small warming delay the formation of the vortex and give us a cold November/December? Or did nothing happen to the vortex and the cold weather caused by something else?

hi its all here

http://forum.netweather.tv/topic/64621-stratosphere-temperature-watch/

 

EDIT: or more specifically here: http://forum.netweather.tv/topic/64621-stratosphere-temperature-watch/?p=1878117

Edited September 18, 2013 by Suburban Streamer

[chionomaniac]

Could anyone help in explaining what happened to the polar vortex in 2010 to cause such a cold and blocked start to the winter?

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/10mb9065_2010.gif

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/temperature/archive/70mb9065_2010.gif

 

From what I can see there was nothing too out of the ordinary both higher and lower in the stratosphere. There was a small warming at 10hpa at the start of November and at the start of December, with nothing unusual happening lower down. Did this small warming delay the formation of the vortex and give us a cold November/December? Or did nothing happen to the vortex and the cold weather caused by something else?

 

There is still a lot to learn about this subject and on the surface the stratospheric conditions were nothing too out of the ordinary in late autumn in 2010. However, at that time of year, the vortex is yet to gain the kind of strength that a prolonged winter cooling would lead to and so is vulnerable to attack. And this attack came in the form of the rare tropospheric led Greenland wave break, which broke into the lower reaches of the stratosphere creating a split, which in turn reinforced the Greenland high. Later on in the season, these types of tropospheric waves will be suppressed by the vortex if it has cooled and strengthened sufficiently.

 

So enhanced tropospheric wave activity was enough to split the lower stratospheric vortex before the stratospheric vortex had increased to it's full winter strength. Quite rare.

[sebastiaan1973]

http://www.geo.fu-berlin.de/met/ag/strat/produkte/winterdiagnostics/index.html

 seems to me this year they publish the stratospheric diagnosis as well

[MattH]

Morning to those awaiting the start of another strat thread. Doesn't a year fly by!....

 

At this relatively early juncture, I just wanted to get a few of my own thoughts down 'on paper'. Sort of starting with the end point and personally I don't think we will see a winter that is in keeping with some of the severe ones that have developed at times within the last 5 or 6 years. Clearly last winter was generally a slow start with December not really delivering anything of any worth and the conditions only changed, primarily, in association with the significant SSW that occurred during January which cleared the way for a particularly interesting and wintry second half of winter and early spring in particular.

 

QBO:

 

As many know the QBO has changed to a more westerly 'phase' compared with the last few years and we are likely to enter into winter in a westerly phase. This is just one small piece of the puzzle, but looking back at a number of years since 1979 that had a September 30mb QBO number within 5.00 of our monthly anom this September (21.36) of which had to fall within 2 months of the westerly QBO peak, the corresponding 500mb pattern is as follows;

That pattern isn't far from the holy grail to be honest, but again the emphasis has to be that this is just one small piece of the puzzle and is unlikely to be the single and primary driving force of the possible synoptic patterns and evolution through the winter. Still, it does make for interesting viewing. My experience with the Eurasion snow cover through October and how this influences the potential patterns through the winter is limited compared with some on this forum, but I must admit there are signs that October will take on a more blocked regime. It looks like the GWO is set to become more -ve soon (-ve AAM) in response to some recent mountain torque events and this may well maintain the signal, which has already developed, for some colder weather to develop across Russian and perhaps Scandinavia as well. Of interest I am expecting quite a blocked and relatively mild October, any zonal/unsettled spells are likely to be short lived and a "proper" stormy October looks distinctly unlikely to me.

 

Amongst some general reanalysis a year of which is evident in the first image posted, is 1990/1991 and there are definitely some correlations there in relation to the QBO once again;

 

2013 30mb QBO numbers from Feb to Sept: -4.13 -0.23 3.12 8.36 14.25 17.89 21.01 21.36
1990 for the same time period: -6.78 -5.74 1.21 5.68 13.06 17.40 19.26 19.32

 

1990/1991 was particularly varied with December producing anything from this;

 

http://www.wetterzentrale.de/pics/archive/ra/1990/Rrea00119901217.gif

 

to this;

 

http://www.wetterzentrale.de/pics/archive/ra/1990/Rrea00119901225.gif

 

A similar pattern continued into January. However and sort of summarizing this brief post, but my thinking is that the end of this winter, once again, may well deliver the goods. A westerly QBO, on paper, isn't good for promoting an SSW event, but that being said they have and still do occur during that phase, but with a tendency for them to be later in the season. Hence why I think, again, that the middle and latter half of the winter could well be when the primary 'wintry' weather becomes dominant. February 1991 for example, produced these kinds of patterns;

 

http://www.wetterzentrale.de/pics/archive/ra/1991/Rrea00119910206.gif

http://www.wetterzentrale.de/pics/archive/ra/1991/Rrea00119910209.gif

http://www.wetterzentrale.de/pics/archive/ra/1991/Rrea00119910228.gif

 

As usual some could argue it is all too late in the season by this point "snow melts quicker by February than it does in December and January" - I think, however, that we have had a brilliant example of how under the right conditions, we can get a major snowfall event in this country well into March, let alone February and clearly that example was earlier this year in late March.

 

So, at this early juncture, my thoughts are on a particularly mixed winter. I don't believe we will see a 2010 December or a winter that is generally dominated by weeks of cold and snowy conditions, most certainly not at first anyway and December (perhaps unfortunately) could well be the mildest of the 3 months in general. I think the trend towards a possible SSW may well take place late January or early February, with February and perhaps March delivering the coldest of the winter weather.

 

Just some thoughts and musings. Looking forward to the new strat thread returning.

 

Regards to all,

 

Matt.

[bobbydog]

quality post matt. keep 'em coming!

[cooling climate]

Mountain torque events events increase the GLAAM as far as I am aware.

[Relativistic]

Mountain torque events events increase the GLAAM as far as I am aware.

My understanding was that they decrease GLAAM because the air masses pushing on the mountains gives an impulse of momentum to Earth from the atmosphere.

[cooling climate]

My understanding was that they decrease GLAAM because the air masses pushing on the mountains gives an impulse of momentum to Earth from the atmosphere.

 

Do not want to side track the thread but I thought that what you describe is friction torque.

Could be wrong though.

[chionomaniac]

My understanding is that positive mountain torques follow positive frictional torques adding energy to the tropical momentum budget and negative mountain torques follow negative frictional torques deflecting momentum northwards away from the tropics.

 

The former is better for reducing west to east flow across more northern latitudes and a more meridional flow is more likely, as well as the posibility that the MT can be deflected into the stratosphere if it is strong enough.

 

 

 

[cooling climate]

My understanding is that positive mountain torques follow positive frictional torques adding energy to the tropical momentum budget and negative mountain torques follow negative frictional torques deflecting momentum northwards away from the tropics.

 

The former is better for reducing west to east flow across more northern latitudes and a more meridional flow is more likely, as well as the posibility that the MT can be deflected into the stratosphere if it is strong enough.

 

gwo_phase_fig4.jpg

 

Positive mountain torques more meridional flow and as you say good

chances of wave breaking and stratospheric warming perhaps.

I do remember GP posting that increased Glaam is what you need for

a more meridional flow. Although it depends on time of year and wave

lengths.

[bobbydog]

lets hope for increased GLAAM!

 

 

 

[Suburban Streamer]

hi everyone

 

Just going back to the QBO.  I remember GP mentioning some time ago that these westerly phases last between 8-11 months. This current phase started in March 2013 and has now more than likely reached its peak.  I've also read a fair bit from various people suggesting a colder second half of winter compared to the first.  Do we think that if we do see a colder jan/feb this may well be influenced by the change to a easterly phase qbo early next year? or at least a fairly weak westerly.

Just to contradict that, i've noticed that stronger westerly phases (this years is the strongest since 1999) tend to drag on for longer (1999 phase lasted 16 months).

Basically, is anyone ready to predict a timescale for a change to east phase qbo?

 

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

[snowking]

hi everyone

 

Just going back to the QBO.  I remember GP mentioning some time ago that these westerly phases last between 8-11 months. This current phase started in March 2013 and has now more than likely reached its peak.  I've also read a fair bit from various people suggesting a colder second half of winter compared to the first.  Do we think that if we do see a colder jan/feb this may well be influenced by the change to a easterly phase qbo early next year? or at least a fairly weak westerly.

Just to contradict that, i've noticed that stronger westerly phases (this years is the strongest since 1999) tend to drag on for longer (1999 phase lasted 16 months).

Basically, is anyone ready to predict a timescale for a change to east phase qbo?

 

http://www.esrl.noaa.gov/psd/data/correlation/qbo.data

 

I find the below link a useful image to keep an eye on in terms of simplifying things:

 

http://www.cpc.ncep.noaa.gov/products/CDB/Tropics/figt3.gif

 

 

The bottom image shows the zonal wind anomalies at 30 and 50hPa - the key area to keep an eye on for the QBO.

 

As you can see as far as August there are hints at 30hPa of it just starting to top out but we will need to wait for confirmation of this with the September update. But that's the simplest way of keep an eye on things.

 

SK

 

EDIT: Another useful link to keep an eye on multiple levels:

 

http://www.geo.fu-berlin.de/met/ag/strat/produkte/qbo/qbo.dat?1378278888

Edited September 30, 2013 by snowking

[anthonym]

Mountain torque events events increase the GLAAM as far as I am aware.

 

Yes, this is true, especially in a regional sense. Easterly wind anomalies basically slow the Earth down, causing +AAM to be transferred from the solid Earth to the air. In the case of mountain ranges, a surface low anomaly to the west of it (and high to the east) will cause a net easterly over the mountain range and slow the Earth even further than if it were just the mountain range alone. So a negative frictional torque and a positive mountain torque contribute to regional +AAM anomalies.

 

The correlation with the AO is actually not so clear-cut; and, in fact, the +MT showed a +AO tendency in some research. This is because the +MT increases the net Mid Latitude westerlies over time, intensifying the jet and PV. There exists an internal AAM cycle across the Mid Latitudes that occasionally is independent of the tropical source to mid latitude sink cycle we are accustomed to (tropical forcing). The internal cycle is simply mid latitude (mainly over the ocean) frictional sinks eating the momentum produced by the mountains in the same latitude-belt. So, not all +MT events are created equal and not all will occur with, and/or lead to, a +GLAAM/meridional flow.

 

I hope this helped.

[joggs]

Are we overdue a Canadian warming?.