"Alastair McDonald" wrote in message
...

"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 :-)


I have never said that every stratwarm leads to a cold UK. What I do say is
that it increases the chances.
My reasoning is simple. A stratwarm will decrease the zonal wind above the
jet (like the present one which is very dramatic at 60N now
http://acdb-ext.gsfc.nasa.gov/Data_s...2012_merra.pdf )
..
This decrease or even reversal will extract energy from the jet due to
increased turbulence and thus increase the potential for blocking. Blocking
increases the chances of winter cold in the UK. There is also a feedback as
stratwarms are usually initiated due to breaking Rossby waves at the
tropopause. This present one certainly was as the warming is still not
evident at 10hPa but is now very suignificant at 150 hPa.

Will
--
http://www.lyneside.demon.co.uk/Hayt...antage_Pro.htm
Will Hand (Haytor, Devon, 1017 feet asl)
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