Stratosphere Temperature Watch 2015/2016

[chionomaniac]

OK so the thinking (or general consensus) is that December will be mild this year? and the potential for blocking not until late December (or more likely - early January)?

I notice that AAM is not mentioned in that forecast Sebastian copied in from Americanwx.

The AAM will be heavily linked to the EN - so even if it is not mentioned it will be strongly correlated to.

[Steve C]

Not really the place for this, but undoubtedly there will be stratospheric elements in it...

 

When (or if) will the NW Winter forecast be issued this year? Always a good read.

[lorenzo]

Will be out before end of this month Steve.

[Steve C]

Will be out before end of this month Steve.

 

Excellent!

[bluearmy]

I agree with most of what ed has posted above but I wonder if the Siberian ridge is going to be the wildcard here. the Greenland PV segment can be strong whilst a stronger ridge to our East than shown on that analog exists. We could well see a colder December than is currently expected if that Siberian block edges west somewhat.

[chionomaniac]

I agree with most of what ed has posted above but I wonder if the Siberian ridge is going to be the wildcard here. the Greenland PV segment can be strong whilst a stronger ridge to our East than shown on that analog exists. We could well see a colder December than is currently expected if that Siberian block edges west somewhat.

I suspect that it will just be out of reach (as per normal in December), Nick. I see that the GFS is resetting the Siberian block further west after the first block is pushed south triggering the NAMT.

[Tamara]

Better indications coming following some erratic MJO modelling that there are signs that the niggling forcing in the IO may be about to subside, and also, just maybe, a very tentative (for now) suggestion from the ECM, at least, that movement of direction is headed towards an engagement of some tropical convection, amidst the general pockets of noise, across the Pacific in time for the start of winter. This occurring in tandem with another WWB associated with a likely swansong kelvin wave to peak the event.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_51m_small.gif

 

This, if it occurs, would have some very good implications tropospherically, and as discussed previously on the MOD thread provide a needed boost back to high AAM tendency to renew those very important Nino feedbacks required this winter to give any chance of sufficiently robust destruction to a +QBO fuelled vortex

[Recretos]

Nothing much I can add to the overall discussions, given the time I have. I admit I have put weather on side for now, so I am just occasionally peaking in here and generally in the strat development.

 

Just gonna add some ENS guidance from the new GEFS version, and also bias-corrected, which is all-in-all the best free ENS guidance for strat at the moment.

 

 

Edited November 20, 2015 by Recretos

[Catacol]

Well - this is interesting. 240h forecast here is not a million miles away at all from what we are surely hoping to see? With a bit of tweaking does this suggest the chance of a SSW event at around New Year?

 

[Ruben Amsterdam]

Hello from Amsterdam, and thanks for all the solid info posted here!

 

I am surprised how quiet it is here. Surely today's 12z isn't too bad, right? 

 

Can someone elucidate to what extend the (imo) unusual high over the Kara and Barentz Sea has something to do with the (minor) warming we see at 10 hPa?

 

One more, maybe stupid, question: is this a wave-3 pattern (temperature wise) developing?

 

 

 

Edited November 21, 2015 by Ruben Amsterdam

[sebastiaan1973]

Of course we see some wave activity, but temperature wise we are still & in the forecast under the normal temperature.

[bluearmy]

Seeing some noticeable wave 1 and 2 activity showing up in a weeks time on Berlin charts. The vortex looks strong at the moment so warmings will probably 'surf' around the edges. by day 10, the zonal wind getting above the 30m/s @ 30hpa which I consider to mean it's slightly stronger than average. Remember it's only just into December at the timescale.

[JOPRO]

Hi, I have a question, was watching a documentary I had skyplused over the weekend about the nuclear arms race, one section of the programme was about the largest nuclear weapon ever tested ( 1500 times the size of the atom bombs dropped at the end WWll,and 10 times the power of every conventional bomb dropped during the war combined!) https://en.m.wikipedia.org/wiki/Tsar_Bomba . Now what caught my eye was where this was detonated was in the far north of Russia on an island on almost the same latitude as Svalbard. Was wondering did this have any effect on the polar vortex? What really caught my eye was the fact that the test was conducted on 30th October 1962 and we all know what happen during the uk winter of 62/63. So was wondering was one of our coldest winter the result of a man made SSW?? From what I can read the fireball from the explosion rose to at least 45,000 feet and the core of the explosion was an estimated 150,000,000 degrees Fahrenheit and the actual radioactive mushroom cloud rose so high it went beyond the stratosphere. Would be interested to know what you guys think??

[Radiating Dendrite]

The Tsar bomb is pretty astounding when you read the figures and at the same time terrifying.

The date is uncanny though; could be coincidence but what happened during that winter was highly unusual.

[BLAST FROM THE PAST]

Best the Russians drop another then up there

 

BFTP

[Terminal Moraine]

According to Wikipedia the test date was Oct 30th 1961. Perhaps it was responsible for one of the coldest March's on record in 1962.

[Nouska]

Perhaps, as with explosive volcanic eruptions, the results linger for a few years. Reading the old papers about the stratosphere in that winter, much is made of the extreme belt of heights stretching from Eurasia to western Canada in late autumn/early winter.

 

A very strong solar cycle was in rapid decline in the previous year - maybe a double whammy on the vortex brought about something so exceptional.

 

[Recretos]

Here is some long range magic from CFSv2 daily ensembles, which I finally managed to average the right way, and they seem to be doing a good job, continuing with the promotion of the vigorous wave1.

 

  

 

Gonna add the NASA model, which I find to be very interesting, and going to 240h, it has forecasting potential together with ECMWF, FIM-9, GFS, JMA and ensemble guidance. 

 

 

Adding comparison of zonal mean zonal wind from NASA, GFS and ECMWF. 

 

  

 

And difference between NASAs GMAO and GFS, showing where GFS has weaker or stronger zonal wind mean component. Not very useful now, but will be when/if stronger dynamics get into play.

 

Edited November 23, 2015 by Recretos

[MichiganWx]

Can I ask a stupid question please?  I have searched literature and my copy of Holton's textbook and I just can't find a clear explanation anywhere.

 

What is meant by "wave 1" and "wave 2"?  I assume "wave 1 forcing" is the energy/momentum transfer resulting from the upward propagation and dissipation in the stratosphere.  But for the life of me, I just don't know what wave 1 and wave 2 means, and I haven't been able to figure it out.  Is it the number of waves?  Does their position matter?  Are they longwave troughs?  ridges?  Both?  I don't get it.

 

I have an MS in atmospheric science

 

Thank you.

[Recretos]

I have done these posts before with images, but somehow Mr. Chionomaniac always seems to forget to add them to the first post.

 

Well, its quite simple really. Wave number 1, mean literally a 1 wave form in the stratosphere. A literal atmospheric wave, or make that like a giant rossby wave if you wish, but not that literally. 

 

An example (a quite strong one, tho, but still). Wave number 2 is the same principle, just with two waves, or two ridges instead of one. This particualr example is one of the CFSv2 ensemble perturbations for 25.12.2015. 

 

 

[Yarmy]

Also, see here:

 

https://forum.netweather.tv/topic/78216-wave-12-activity/

[MichiganWx]

Thank you both so much.  It has been so frustrating not knowing something so elementary.

 

[chionomaniac]

Thank you both so much.  It has been so frustrating not knowing something so elementary.

 

The only daft question is the one you don't ask. It took a while for me to work it out when I first started looking at the strat! Next year I will put an explanation in the first post.

[Singularity]

Funny that we don't just call it 2-Wave activity really. Its easy enough to imagine once you know it's about having two ridges at play - essentially the vortex is 'pinched'. It sounds very painful but who likes a rampant polar vortex anyway? 

 

From what I've seen in recent years, wave 1 seems relatively kind to the vortex, giving it a shove and potentially weakening it a fair bit but with plenty of potential to bounce back later.

Edited November 24, 2015 by Singularity

[Recretos]

Oh trust me, a full on wave 1 can be a harder case for the vortex to handle than a wave 2. if the vortex is strong, it can take the "energy" of the 2-wave and use it to its own advantage, remaining firm in place, unless a strong enough temp. waves are following. While in a full blown wave 1 it will get shoved out of place before it can say "is that a wave1 coming at me...". Of course with the normal disclaimers, like each scenario is different and each situation is unique.