In article 20140105154938.31c41adb@home-1,
Graham P Davis writes:
On Sun, 5 Jan 2014 10:52:52 +0000
John Hall wrote:


What might be helpful as a predictive tool would be to know precisely
where the SSW began, but unfortunately the NOAA graphs don't tell you
that. They merely give the average (I assume) temperature for the
whole Arctic region (strictly speaking for north of 65N, but that
near enough corresponds to the Arctic Circle).

What seems to be happening is a split in the Polar vortex with one lobe
extending into North America and the other into Russia.

Yes, I've noticed that on the model forecast charts the usual purple
blob to the top left has been joined by another at the top right, which
is presumably a symptom of that.

Whether this is
typical of how an SSW develops, I'm sorry to say that I've no idea.


But is it the vortex split that leads to the SSW or vice versa? If it's
the vortex split that comes first, that would imply that it's that that
we should look out for rather than SSW.

I'm aware that meteorologists have almost certainly been researching all
this for decades, making it very old hat, but it's fun to investigate it
for oneself.
--
John Hall "He crams with cans of poisoned meat
The subjects of the King,
And when they die by thousands G.K.Chesterton:
Why, he laughs like anything." from "Song Against Grocers"