In article ,
"Keith (Southend)G" writes:
Thanks John for looking at some of the past SSW situations. What
does seem certain, is a change in weather type can be expected
when one occurs and I'm sure some 'others' may have a better
idea at some of the differences in SSW set-ups and a better idea of
the outcome on the ground. But we have come a long way in
meteorology over the years to a point where we monitor a
previously unknown feature and now look in anticipation at what
effect it may have in the coming weeks. All good stuff.

Yep. I suppose the next step would be to discover what triggers a SSW
(which I assume is currently unknown).
--
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"

On Sunday, 5 January 2014 10:54:52 UTC, John Hall wrote:
In article ,

"Keith (Southend)G" writes:

Thanks John for looking at some of the past SSW situations. What

does seem certain, is a change in weather type can be expected

when one occurs and I'm sure some 'others' may have a better

idea at some of the differences in SSW set-ups and a better idea of

the outcome on the ground. But we have come a long way in

meteorology over the years to a point where we monitor a

previously unknown feature and now look in anticipation at what

effect it may have in the coming weeks. All good stuff.



Yep. I suppose the next step would be to discover what triggers a SSW

(which I assume is currently unknown).

--

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"



What I want to know is how they figured in previous memorable cold spells say 62/63, 78/79 & 81/82 and so on

Also as you say John what causes them and are they linked to the earths temperature?

On Saturday, January 4, 2014 9:36:46 PM UTC, John Hall wrote:
In article ,

"Keith (Southend)G" writes:

And then ones wonders what the SSW stiuation was in years like

1947 and 1963, especially when 1947 didn't get going until later in

January, but here I go again marching up that hill LOL.



Sadly I don't think the measurements would be available for 1947, and

probably not for 1963 either. The NOAA record only goes back as far as

March 1979.



You can access their archive he



http://www.cpc.ncep.noaa.gov/product...e/temperature/



Here's the 10mb graph for 1985 and 1986:



http://www.cpc.ncep.noaa.gov/product...b9065_1986.gif



The cold Jan/Feb of 1985 seem to have been preceded by a major SSW in

Dec 1984. The very cold Feb 1986 was preceded by a rather "jerky" SSW in

Dec 1985 and Jan 1986. Of course that doesn't prove that they were cause

and effect.

--

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"

Thanks John.It's just refreshing to see this couched in these (correct) terms.

In article ,
Lawrence Jenkins writes:
What I want to know is how they figured in previous memorable
cold spells say 62/63, 78/79 & 81/82 and so on
snip

As I mentioned, unfortunately the NOAA archive only starts in March
1979. I think I did look at 1981-2 and there was no real sign of a SSW.
But that was a very unusual winter. It started early and finished early,
and it didn't have a prolonged easterly spell, the cold weather coming
from the north IIRC.

The other point to make is that major SSW events never seem to begin any
earlier than late December. It could be linked to severely cold
Decembers beingrare in the UK, and that when they do occur they don't
often feature prolonged spells of easterlies.
--
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"

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

--
Graham P Davis, Bracknell, Berks. Mail: 'newsman' not 'newsboy'.
'Do your bit for climate change this holiday period by restricting your
intake at festive mealtimes to four Brussels sprouts or less.'
@3WhitehallPlace

On Sat, 4 Jan 2014 21:36:46 +0000
John Hall wrote:

Sadly I don't think the measurements would be available for 1947, and
probably not for 1963 either.

I think we need to look down rather than up to find the reason for the
62-3 winter and this one.

The anomalous pressure distribution for the 62-3 winter was attributed
to favourable SST anomalies in the NE Pacific (Namias area) and the
Atlantic off the Grand Banks. In both areas the water was colder than
normal.

In winter, a cold Namias area is associated with lower than normal
pressure south of the Bering Strait and high between the pole and the
Canadian Archipelago. This set-up means that the coldest air will move
into Russia. Conversely, a warm Namias area, such as we have this year,
is associated with cooler than usual winters in the eastern two-thirds
of the USA.

Over Europe and the North Atlantic, a cold Namias area is associated
with high pressure centred near the Russo-Finnish border and low just
west of Ireland. The pressure anomalies associated with a cold pool
south of the Grand Banks are high over Iceland and low over the Azores.
It seems that, in 1962-3 the two sea areas being cold combined to
produce the harsh winter.

This year, as I said, the Namias area is warm and this is giving the
cold winter in NE America. Over this part of the world, one would
expect a high pressure anomaly centred just west of Ireland which
obviously hasn't happened. Although there is a warm pool south of the
Grand Banks, it's elongated W-E and a little further south than
necessary so the effect of this would be to increase zonality.

--
Graham P Davis, Bracknell, Berks. Mail: 'newsman' not 'newsboy'.
'Do your bit for climate change this holiday period by restricting your
intake at festive mealtimes to four Brussels sprouts or less.'
@3WhitehallPlace

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"