Link http://weather.unisys.com/surface/sst_anom.html

La Nina conditions showing up nicely off the Western coast of Peru
now.

Warm patch SW of Greenland, and a couple of cooler patches SE of
Newfoundland / Mid Atlantic.

Large cool patch in NE Pacific & large warm patch NW Pacific / Japan.

But what does it all mean for this coming winter in North West Europe?

Any thoughts.

Should read, large warm patch stretching from SW of Greenland to
Iceland.

On Oct 22, 9:09*am, Teignmouth wrote:
Should read, large warm patch stretching from SW of Greenland to
Iceland.

There are going to be a lot of people on this ng trying to forecast
the coming winter by looking at sea surface temperature anomalies and
good luck to them.
Scientists often try to explain climate anomalies in
terms of anomalies in sea surface temperature (SST).

Back in the seventies, some thought that colder than normal water
in the west N.Atlantic favoured blocking anticyclones in Europe,
and an enhanced north-south SST gradient was associated
with active N. Atlantic depressions.

Things have not really progressed much in terms of seasonal
forecasting since those days.

The warm patch SW of Greenland to Iceland does not really give us a
good handle on a seasonal forecast. It is all about persistence and
the size of the anomaly.

The feedbacks between ocean and atmosphere are complex
and on many space and timescales.
Ultimately, the atmosphere determines SST which then
influences the atmospheric circulation
So we are left with a chicken or egg argument.

Len Wood
Wembury, SW Devon

On 22 Oct, 10:56, "Will Hand" wrote:

with reduced snowfall in SE

I'm glad to see you've parameterised my location for this winter and
considered this in your forecast...

Richard

On Friday 22 October 2010 09:07, Teignmouth scribbled:

Link http://weather.unisys.com/surface/sst_anom.html

La Nina conditions showing up nicely off the Western coast of Peru
now.

Warm patch SW of Greenland, and a couple of cooler patches SE of
Newfoundland / Mid Atlantic.

Large cool patch in NE Pacific & large warm patch NW Pacific / Japan.

But what does it all mean for this coming winter in North West Europe?

Any thoughts.

Last year, the N Atlantic SST pattern didn't show its hand until near the
end of November so I think it's too early to tell. I've wondered whether the
change of relative temperatures between sea and land in spring and autumn
might cause changes in SST anomaly patterns which then become more settled
during winter and summer.

--
Graham Davis, Bracknell, Berks. E-mail: "newsman", not "newsboy".
"It pays to keep an open mind, but not so open your brains fall out." - Carl
Sagan

On Oct 22, 8:56*am, Len Wood wrote:

The feedbacks between ocean and atmosphere are complex
and on many space and timescales.
Ultimately, the atmosphere determines SST which then
influences the atmospheric circulation
So we are left with a chicken or egg argument.

Len,

While what you say is true, I don't think we should despair. The SST
temperatures depend on the atmosphere, so that means we can see how
the atmsophere is behaving by looking at the SSTs. In other words,
using Will's/a holistic approach, and taking the Ocean-Atmosphere as
one system, then we can get an idea of its state by looking at SSTs.

In other words, when the SSTs register an El Nino, or a La Nina, we
can predict the weather in North and South America. The same should be
true for the North Atlantic SSTs and Europe.

What is interesting is that the SST patterns seem to extend from the
Pacific to the Atlantic. There is a cold trough running across the
Pacific at the Equator. On either side of it are cool wedges with
their points in the west. The southern wedge also appears in the South
Atlantic, with just a hint of the Northern wedge in the North
Atlantic. But the cold trough does not appear in the Atlantic. In the
Pacific, north of the cool wedge is the start of a warm wedge around
Japan. This warm wedge gives way to a cold wedge in mid Pacicfic but
returns as a warm wedge in the North Atlantic south of Greenland.

I see these patterns, not as regular, but as fractal. In other words
they are deterministic. So they represent the state of the climate
system now, and should be useful in predicting the climate later in
the year. For instance, Joe *******i predicted this La Nina by
spotting the the El Nino conditions earlier in the year. Not a clever
trick you say? Well Lawrence thinks so!

Cheers, Alastair.

On 22/10/2010 11:17, Richard Dixon wrote:
On 22 Oct, 10:56, "Will wrote:

with reduced snowfall in SE

I'm glad to see you've parameterised my location for this winter and
considered this in your forecast...

Richard


I dont think Will has forgiven us for having as much snow as him since
he moved away from the SE!!

Phil

On Oct 22, 12:29*pm, Alastair wrote:
On Oct 22, 8:56*am, Len Wood wrote:

The feedbacks between ocean and atmosphere are complex
and on many space and timescales.
Ultimately, the atmosphere determines SST which then
influences the atmospheric circulation
So we are left with a chicken or egg argument.

Len,

While what you say is true, I don't think we should despair. The SST
temperatures depend on the atmosphere, so that means we can see how
the atmsophere is behaving by looking at the SSTs. In other words,
using Will's/a holistic approach, and taking the Ocean-Atmosphere as
one system, then we can get an idea of its state by looking at SSTs.

In other words, when the SSTs register an El Nino, or a La Nina, we
can predict the weather in North and South America. The same should be
true for the North Atlantic SSTs and Europe.

What is interesting is that the SST patterns seem to extend from the
Pacific to the Atlantic. There is a cold trough running across the
Pacific at the Equator. On either side of it are cool wedges with
their points in the west. The southern wedge also appears in the South
Atlantic, with just a hint of the Northern wedge in the North
Atlantic. But the cold trough does not appear in the Atlantic. In the
Pacific, north of the cool wedge is the start of a warm wedge around
Japan. This warm wedge gives way to a cold wedge in mid Pacicfic but
returns as a warm wedge in the North Atlantic south of Greenland.

I see these patterns, not as regular, but as fractal. In other words
they are deterministic. So they represent the state of the climate
system now, and should be useful in predicting the climate later in
the year. *For instance, Joe *******i predicted this La Nina by
spotting the the El Nino conditions earlier in the year. Not a clever
trick you say? *Well Lawrence thinks so!

Cheers, Alastair.

Quite right Alastair. It was not my intention to drive anyone to
despair.
Many of us have experience which is not to be sneezed at.
A holistic approach as Will mentioned is a good way forward.
The Arctic ice situation is a bit different than it was in the
seventies so that is another thing to be considered.

As I said, I wish you all good luck, you are all a lot braver than me.
I shall be reading posts with interest.

Len Wood
Wembury, SW Devon

On 22 Oct, 17:40, Len Wood wrote:

Is that 10,000 ensembles you are talking about Richard?

What are the boundary conditions and when is the starting time?
Not sure about NAO. That is just an rough indicator of atmospheric
conditions in the North Atlantic. It is those that need predicting.

To use a hackneyed phrase 'the devil is in the detail'.

Rodwell and Folland (QJ 2002) found a correlation between
May SST in the N. Atlantic and the following winter NAOI.
It was only just statistically significant though.

This was mere thinking out loud. Run, say, 100 simulations of 100
years of "present day climate" forced in some way by the current
climate (and SSTs, or slight variation thereof) to give 10,000 years
of simulated "weather" which might provide you with a wider base for
selecting analogue years when attempting to forecast ahead, provided
the 100 simulations provide enough variability about our current
climate.

Richard