[Stratosphere Temperature Watch 2013/2014]

 According to GFS06 fi, the vortex reforms slightly, but pressure on the vortex is ramped up again at the end of the run

 

 

 

 

 

 

 

 

Same signature at 10hPa. 

 

[Stratosphere Temperature Watch 2013/2014]

It's back. And a tiny bit stronger again (at 10hPa) than the 12z run. 

[Stratosphere Temperature Watch 2013/2014]

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

 

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[Stratosphere Temperature Watch 2013/2014]

http://www.americanwx.com/bb/index.php/topic/41639-seasonal-winter-20132014-forecast-based-on-opi-index/page-2

 

If they creators of OPI are right (until now they are!) tropsheric wave activity should be low in januar. So the polar vortex will resist the coming on attack by wave 2 and in some degree wave 1 but will recover. Not only by not crossing the surfzone but secondly no follow up by any significant wave activity. Interesting times ahead!

 

 

Hi Sebastiaan,

 

I'm still not sure about what's actually plotted (it's not a standardized something, as the average line is not at 1) on the y-axis of this graph, but that's not my main point. By the way, do they refer to wave 1 and 2, or shorter waves as well?

 

This graph shows only troposferic wave-activity. Couldn't it be possible -hypothetically- that the maximum in february is forced by the stratosphere, i.e. by some sort of wave-induced event (either minor or major warming) in mid-january?

 

My point being: how relevant is troposferic wave (1/2) activity? Last years wave-1 activity was of course high during and after the SSW, but I'm not exactly blown away by the troposferic wave response. Or should we be looking at wave-3 and up?

 

And yes, I would love skating on the canals and lakes here. You know I'm a big fan. Even a minor event or a discplaced vortex may bring the ice we want

 

Cheers and merry Xmass

[Stratosphere Temperature Watch 2013/2014]

Hi all,

 

my first post on this forum. I've been reading all the brilliant posts here for some two years and decided to sign up! This forum stirred my interest in the stratosphere and the way we can (potentially) use it for long range weather forecasts. You really are doing a nice job here, keep up the good work!

 

I spotted something new in the GFS06z FI: a pulse of warming over the Canadian sector. Might be just the push over the edge (of the cliff) our beloved vortex needs?