Stratosphere Temperature Watch 2013/2014

[mcweather]

It's Xmas so only positives allowed today, so based on that, how about this... Just as the very strong Wave2 activity backs off...

 

ecmwfzm_ha1_f240.gif

 

Wave2 and Wave1 alternating attacks? If this continues to show there will be a wide variety of FI charts on offer in the coming days/weeks I would imagine. All eyes on where the vortex is going to get displaced to?

 

Merry Christmas  s4lancia, could be some nice belated xmas pressies if this keeps up. Greetings from Braodmayne where we've had hail and sleet in the showers. so technically a white xmas. lol

[sebastiaan1973]

UKMO refers to a potential SSW at the end of the winter.

http://www.metoffice.gov.uk/media/pdf/i/i/A3_plots-temp-JFM.pdf

Edited December 25, 2013 by sebastiaan1973

[Cloud 10]

Wave 2 activity still strong but declining at day 10..

 

 

...but wave 1 really ramping up at same time.

 

 

 

This 30mb free-fall cant last forever!

 

 

 

 

[bluearmy]

ecm op from yesterday had the 10hpa max above zero at day 10 !!  

 

some serious wave 1 now predicted by day 10 but this will probably verify at a lower amplitude.

[lorenzo]

The wave activity excitement on ECM, I cannot buy into yet, have developed a healthy distrust of the ECM this year, to dig out another phrase, jam tomorrow with respect to the EP Flux. Big Wave Activity but serving to concentrate the vortex and it appears to reform as robust as ever, absorbing everything.

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_WAVE2_MEAN_OND_NH_2013.gif

 

 

Some GFS charts out at day 10.

 

10hPa

 

 

 

30hPa

 

 

So, are we looking at a January with the vortex ruling the roost, or, are we going to get continued wave activity chipping away at it with the current Wave 2 and Wave 1 having opened the door, like to think that if any MJO assistance is going to occur the EC32 will begin to see it on today's weekly.

 

Edited December 26, 2013 by lorenzo

[Recretos]

Wave 2 activity still strong but declining at day 10..

 

...but wave 1 really ramping up at same time.

 

 

Naturally. As one wave decreases, the values of the other one can ramp up if it holds its position, since the zonal mean amplitude of one wavelength is generally higher than a double wave zonal mean.

There is a limit to how much the double wave can compress the vortex (without an SSW or a general split). So as one wave starts to back off, the pressure on one side of the vortex is being decreased and the dominant wave can start pushing the vortex (if strong enough). Or in layman's terms, the energy of the compression is being released towards the weakening wave, naturally trying to reshape the vortex. And if at that stage the wave1 is strong enough to hold the energy "release", than the vortex can get from the "sausage" look directly into a displacement or at least into a quasi-displacement reformation.  

As for the actual values on the wave graphs, it is also only natural that as wave2 decreases, wave1 will pick up since it is "taking" over the matter, and it is usually on a shorter wavelength. So it also has generally higher values. Having a 1500m' wave 2, is in general terms as strong as 2500-3000m' wave 1, which is a lot. Tho this is just for the "feeling" of it, since of course it varies from case to case. 

 

[bluearmy]

Just as the operational ECM in the trop can often over amplify etc by day 10, is the same true higher up? the Berlin data is derived directly from the op run so i suspect this is probably the case. On the same basis, once the gfs op goes past day 8 I guess it also becomes questionable in its detail if not its trend.

[karyo]

 

 

This 30mb free-fall cant last forever!

 

pole30_nh.gif

Is this a record/near record value? I don't remember seeing such low temperatures before...

 

Karyo

[lorenzo]

Just as the operational ECM in the trop can often over amplify etc by day 10, is the same true higher up? the Berlin data is derived directly from the op run so i suspect this is probably the case. On the same basis, once the gfs op goes past day 8 I guess it also becomes questionable in its detail if not its trend.

 

Good questions, need some re-analysis or verification figures. Too confusing for me, would be good if the strat. charts had graphs similar to the usual model verification ones. Perhaps Recretos can tell us more..

 

There are these charts on the CPC page for GFS, but not really monitored them closely enough to look for trends.

 

Temps

 

Zonal Winds

Edited December 26, 2013 by lorenzo

[aginob]

hi all user

 

off topic question

is possible here at this community forum netweather

have the link or source when user posting models ?

 

http://forum.netweather.tv/topic/78161-stratosphere-temperature-watch-20132014/?p=2875614

 

thanks !

[Cloud 10]

Is this a record/near record value? I don't remember seeing such low temperatures before...

 

Karyo

 

I does look to be at almost record low values if i am reading this graph correctly.

 

acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_2013_merra.pdf

[mountain shadow]

That record low PV temp is surely a good thing? . When it goes, it should quickly according to GP.

[sebastiaan1973]

Well, I don't know. E.g. 2000. It remained low.

http://acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_1999_merra.pdf

[Cecil Hogmanay Melchett]

Cold zonality seems to be our only hope as we move forward.

I think the excellent thread is highlighting perfectly just what an important part of the jigsaw the strat is.

There is pretty much zero hope of any blocking structures across Greenland at present IMHO,unless we see a pretty big SSW soon my hopes for January will begin to recede quite quickly.

[aginob]

hi to all

http://forum.netweather.tv/topic/78161-stratosphere-temperature-watch-20132014/?p=2872373

 

a m s for the northern hemisphere ... a m s for the southern hemisphere

 

source: http://acd-ext.gsfc.nasa.gov/Data_services/met/ann_data.html

[Don]

I does look to be at almost record low values if i am reading this graph correctly.

 

acdb-ext.gsfc.nasa.gov/Data_services/met/metdata/annual/merra/t90n_30_2013_merra.pdf

 

 

Yes, that does look pretty ugly that graph doesn't it!

[karyo]

The vortex is proving unbreakable so far.

Mind you, the GFS forecasts the wave activity to continue well into January which I suppose is in contrast with the OPI forecast (posted a few pages back) which went for a quiet January wave wise.

Karyo

[Snowynorth]

Looks promising!!!!

 

[chionomaniac]

Great to see the wave activity forecast for early January - no surprise to see it but do note that the heat is being fluxed away from the pole and that this will neither propagate effectively, nor destroy the vortex. However, we will see the start of the feedback system that, when the next upsurge of wave activity occurs later on in January, we will have a better chance of a more severe vortex disruption.

[Ruben Amsterdam]

When dealing with wave "activity", there is one vital thing to keep in mind. Troposphere and stratosphere are on two different "planes" (nothing new there lol),  Meaning, that as we all know, most of the atmosphere' mass is in the troposphere. And as we rise up, the pressure is falling fast at first, and the higher we go it is basically falling on a logarithmic scale. The height is increasing at the same rate, while the pressure drop is getting lesser the higher we go. Basically what I am trying to say is, that 1km of height difference in the mid to upper stratosphere. may only mean the difference of 1 or 2mb (in general terms), while in the troposphere it can mean a difference of 100-150mb. At the same time, when going through a horizontal distance on a single pressure level, lets say 500mb, you are going to have a faster and smaller height change in a wave (100-200m, depending on the wave amplitude), than when compared to the stratospheric waves when you are going to have a wave on a bigger distance, but much more amplified (800+m), due to the reasons I mentioned above and some general rules of meteorology. So most (if not all) of the time the tropospheric wave amplitudes are all but impressive when they are on the same graphical scale as the stratospheric waves.  

 

Just a graphical example, I draw you "basic-general" wave amplitude in comparison at different height. Y axis is height in milibars, and X is horizontal distance. The height is only to represent, well, the height (isobaric).  (tho the horizontal distance of the waves is not really in realistic proportions).

 

 

As for the troposphere, due to the generally know causes, you can have more than 2 waves, up to 5 at least, depending if you count shortwaves or not. 

GFS and some other models actually have a special parameter, called "5-wave geopotential height" that is calculated only for 500mb. When compared to normal height map, it averages out the field to a max 5 waves. Basically showing more or less just the (actual) long waves (Rossby waves).

 

Practical example:

 

 

 

 

 

Regards.

 

 

Thanks for the info! It makes complete sense

 

A spectacular looking 30 hPa graph by JMA this morning. Spectacularly wrong, of course

 

.

Edited December 28, 2013 by Ruben Amsterdam

[sebastiaan1973]

Great to see the wave activity forecast for early January - no surprise to see it but do note that the heat is being fluxed away from the pole and that this will neither propagate effectively, nor destroy the vortex. However, we will see the start of the feedback system that, when the next upsurge of wave activity occurs later on in January, we will have a better chance of a more severe vortex disruption.

Chio, perhaps you can explain in some what more detail how in your opinion the feedback system works, so we have a better chance for more severe vortex disruption later on in januar. Thanks!

[lorenzo]

Couple of charts from the Berlin site from the latest run to illustrate the wave activity. Getting warmer at both 10hPa and 30hPa.

 

Max Temp on this run for 10hPa spans from -36C at analysis to -8C

 

For 30hPa analysis max temp. begins at -46C to -29C.

 

Leading to a strong change in the zonal wind strength, down from 220 mph to 134mph, so whilst reduced by nearly 100mph, still ramping away..

 

Wave 1 - above 2000 at day 10 now.

 

Wave 2 Peaks at day 6.

 

A decent attack on the vortex however it remains solid as shown by the lack of red arrows pointing right i.e poleward on the trop and strat EP flux charts.

 

From 4th Jan just into negative AO territory, ECM control run more negative, where you could argue that if using -1 to 1 as neutral then the mean remains as a neutral AO.

 

Considering the giant wave activity to achieve just a neutral > slightly negative AO, really underlines the vortex strength. More wave action needed, however GEFS sees this differently, looking at the range in green around the mean, solid negative.

 

Some model divergence to pick through which makes both the assault on the vortex and the resulting fallout all the more interesting, another meaningful Wave 1 later in January and goodnight vortex would be my guess at this stage.

 

Sources - as per request above to add links to posting

http://models.weatherbell.com/

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

http://ds.data.jma.go.jp/tcc/tcc/products/clisys/STRAT/index.html#monit_nh

http://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/diag.php?lng=eng

 

 

 

 

 

[bluearmy]

Yep Lorenzo, no chance of those super strength zonal winds leading to a 'SNAP' change, under wave pressure. Instead a gentle dropping off in the zonal winds and a slightly weakened vortex, should further wave activity occur next month. within a fortnight, we will probably have seen the peak of the strat vortex strength for this winter. A very slow subsidence thereafter or something more notable ?? Ed thinks the latter and he hasn't been far wrong as yet.

[Severe Siberian icy blast]

Great to see the wave activity forecast for early January - no surprise to see it but do note that the heat is being fluxed away from the pole and that this will neither propagate effectively, nor destroy the vortex. However, we will see the start of the feedback system that, when the next upsurge of wave activity occurs later on in January, we will have a better chance of a more severe vortex disruption.

Hi chiono , so is there any particular reason why the heat flux is going away from the pole? Does the strength of the vortex have a say on diverting the heat flux away from the pole? Or is just coincidence ?im guessing there's a driving mechanism that determines which way it will go?

[chionomaniac]

Chio, perhaps you can explain in some what more detail how in your opinion the feedback system works, so we have a better chance for more severe vortex disruption later on in januar. Thanks!

Simply put it is explained as per the plate spinning post. Once the first wave has disturbed the flow of the vortex the next wave has an even better chance of further disruption.

 

More complexly one needs to look at the GWO and transfer of AAM from equatorwards towards the poles and the subsequent positive mountain torques and then deflection of the waves into the stratosphere.

 

Lets look at what has just occurred. Up until recently we have seen the polar vortex strengthen unopposed without any strong wave activity from November. However now we have seen the GWO enter into phase 5 territory:

 

 

This has been due to more significant positive AAM anomalies over the NH especially north of 60ºN and a recent Asian MT - the first significant one of the season (this can be then retraced back to tropical convection patterns seen through the recent OLR signature - remember that this is one of the first things that GP looked at as it can be used as a guidance to where the GWO is heading))

 

 

 

- note the increase of tropical convection highlighted south of Eastern Asia.

 

The net effect of positive AAM north of 60ºN will be to weaken the westerly flow at that point - hence a slight weakening of the overall polar vortex has been programmed in the modeling tropospherically, whilst the upper vortex also takes a blow stratospherically from the deflected wave activity. One would expect another round of favourable tropical convection so occur in around 20-25 days and this will have an even greater affect, as the stratospheric vortex will be weakening in line with seasonal change and the westerly QBO is also likely to be weaker. 

 

I still don't think that the current round of wave activity is enough to break the vortex, but at least the dominance of the strong vortex conditions are being challenged and this will be reflected in the NWP output, and as this occurs the likelihood of colder outbreaks increases over the UK as one of the results of the initial weakening of the PV will be a more southerly based jet stream.