"Freddie" wrote in message
.net...
On Wed, 26 Dec 2012 12:22:18 -0000, "Alastair McDonald"
wrote:
Yes, but the net the zonal flow must always be zero otherwise all
the air
would gather at one longitude.
That's not strictly true, as you are not taking into account vertical
motion.

I don't think a stratwarm centred on Moscow would bring us snow.
In my earlier reply, I was actually going to add that there are probably
_bad_ places for it to occur - but when I wrote the sentence it looked a
bit patronising, so I deleted it. I agree with what you are saying up to
a point, but as I said before I think you are over simplifying the
dynamics.

Yes, I can find it difficult to express an honest opinion without sounding
abrasive. For instance, isn't it Will who is being simplistic expecting that
every stratwarm will lead to a cold UK? But perhaps he is just being
optimistic :-)

My ideas are simple because I am trying to understand the underlying
mechanism. If stratwarms are the missing piece of the jigsaw, then it
may be possible to construct a simple model of polar winters. I think
that within fifty years we will be able to predict the
movements of the polar vortex and the polar night jet stream, if they still
exist then. (With no polar ice we may have a permanent stratwarm, and no
polar vortex.)

As I see it the stratwarm does not replace the polar vortex, just push it
off the pole. Am I correct? So it depends in which direction that nudge
is - into the eastern or western hemispheres.

I also see the polar night jet determining the polar front. When a stratwarm
occurs the length of the polar night jet increases but its average latitude
remains the same. If a large oscilation brings the polar front south over
the UK then we get cold weather. But the oscilations in the polar night jet
possibly depend on topography and atmospheric tides. So I agree that I did
oversimplify the dynamics but I do believe that they can be determined.

Cheers, Alastair.