The more I look into the subject of SST anomalies and cold winters the
more I run into trouble. The link below is what I imagine an ideal SST
anomaly set-up in November for a -ve NOA / easterly set-up in the
winter. The problem is, it's 1997. Winter 1998 was anything but cold. I
know one example proves nothing, but it appeared incredible as it was
the first one I hit on.

https://www.fnmoc.navy.mil/products/...sstanomaly.gif
--
Keith (Southend)
http://www.southendweather.net

Hi Keith (and everyone else),

Interesting post, just wondered why you imagine this is the ideal SST setup
for a -ve NAO?

My thinking (and I may be wrong) is that with warmer sea temperatures west
of the UK this would aide convection, hence encourage the westerlies, i.e
+ve NAO.

Just looking at the current anomaly, would the colder temperatures in the N
Atlantic west of 30W aide the development of high pressure in that region?

I may be embarrassingly wrong, and no doubt someone will point it out if I
am. Just a thought though,

Best wishes,
Simon


--
Weather Consultancy Services / Weather School
The Weather Centre, 188 Common Road, Wombourne, South Staffordshire. WV5
0LT.
Tel: 01902 895252
email:

http://www.weatherweb.net
http://www.weatherschool.co.uk
http://www.atlanticweather.co.uk
"Keith (Southend)" wrote in message
...
The more I look into the subject of SST anomalies and cold winters the
more I run into trouble. The link below is what I imagine an ideal SST
anomaly set-up in November for a -ve NOA / easterly set-up in the winter.
The problem is, it's 1997. Winter 1998 was anything but cold. I know one
example proves nothing, but it appeared incredible as it was the first one
I hit on.

https://www.fnmoc.navy.mil/products/...sstanomaly.gif
--
Keith (Southend)
http://www.southendweather.net

I think that SST anomalies are of limited value in forecasting, except on
the local scale. The current SST is a reflection of what has happened to
that area of water in the past. It has a close affinity to the weather
patterns that have existed in in the past few days extending back to weeks
with decreasing amplitude of effect. Long-wave global dynamical patterns in
the mid-upper troposphere that largely determine the run of events in
mid-latitudes, are reasonably co-herent in the medium term. However, the
dynamics of the mid-upper troposphere is little influenced by small
relatively local SST anomalies compared with the overall inbalances that
naturally exist between the equator and poles.


--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.btinternet.com/~wokingham.weather/wwp.html
"Keith (Southend)" wrote in message
...
The more I look into the subject of SST anomalies and cold winters the
more I run into trouble. The link below is what I imagine an ideal SST
anomaly set-up in November for a -ve NOA / easterly set-up in the
winter. The problem is, it's 1997. Winter 1998 was anything but cold. I
know one example proves nothing, but it appeared incredible as it was
the first one I hit on.


https://www.fnmoc.navy.mil/products/...bl_00_sstanoma
ly.gif
--
Keith (Southend)
http://www.southendweather.net

Bernard Burton wrote:
I think that SST anomalies are of limited value in forecasting, except on
the local scale. The current SST is a reflection of what has happened to
that area of water in the past. It has a close affinity to the weather
patterns that have existed in in the past few days extending back to weeks
with decreasing amplitude of effect. Long-wave global dynamical patterns in
the mid-upper troposphere that largely determine the run of events in
mid-latitudes, are reasonably co-herent in the medium term. However, the
dynamics of the mid-upper troposphere is little influenced by small
relatively local SST anomalies compared with the overall inbalances that
naturally exist between the equator and poles.


--
Bernard Burton
Wokingham, Berkshire, UK.

I guess if there was a definate link with SST anamolies and our weather
it would all be to easy. At the end of the day we all seem to be
clutching at straws g

--
Keith (Southend)
http://www.southendweather.net

Yes Keith, that about sums it up. It's all the King's New Clothes syndrome.
These fads come and go, as someone's new theory becomes fashionable. But
scientific it ain't, and about as useful as throwing a few chicken bones on
the floor, a custom still practised in some places, and sometimes used in
matters of life and death for some unfortunate.

--
Bernard Burton
Wokingham, Berkshire, UK.

Satellite images at:
www.btinternet.com/~wokingham.weather/wwp.html
"Keith (Southend)" wrote in message
...
Bernard Burton wrote:
I think that SST anomalies are of limited value in forecasting, except
on
the local scale. The current SST is a reflection of what has happened to
that area of water in the past. It has a close affinity to the weather
patterns that have existed in in the past few days extending back to
weeks
with decreasing amplitude of effect. Long-wave global dynamical patterns
in
the mid-upper troposphere that largely determine the run of events in
mid-latitudes, are reasonably co-herent in the medium term. However,
the
dynamics of the mid-upper troposphere is little influenced by small
relatively local SST anomalies compared with the overall inbalances that
naturally exist between the equator and poles.


--
Bernard Burton
Wokingham, Berkshire, UK.

I guess if there was a definate link with SST anamolies and our weather
it would all be to easy. At the end of the day we all seem to be
clutching at straws g

--
Keith (Southend)
http://www.southendweather.net

"Bernard Burton" I think that SST anomalies are of limited value in
forecasting, except on
the local scale. The current SST is a reflection of what has happened to
that area of water in the past. It has a close affinity to the weather
patterns that have existed in in the past few days extending back to weeks
with decreasing amplitude of effect. Long-wave global dynamical patterns
in
the mid-upper troposphere that largely determine the run of events in
mid-latitudes, are reasonably co-herent in the medium term. However, the
dynamics of the mid-upper troposphere is little influenced by small
relatively local SST anomalies compared with the overall inbalances that
naturally exist between the equator and poles.



I think it's worth pointing out that the regime in the North Atlantic sector
depends on the strength of the polar vortex.When the vortex is strong there
is a single strong zonal jet across the NA,during times of weak vortex there
tends to be two weaker jets-eastern and western in the sector.The
statistical dependence on SST distributions differs entirely for the two
different regimes,

--
regards,
David

add '17' to Waghorne to reply

"Bernard Burton" ..
Yes Keith, that about sums it up. It's all the King's New Clothes
syndrome.
These fads come and go, as someone's new theory becomes fashionable. But
scientific it ain't, and about as useful as throwing a few chicken bones
on
the floor, a custom still practised in some places, and sometimes used in
matters of life and death for some unfortunate.

Really Bernard this is most unfair !!
Seasonal forecasting based on SSTs i suppose fell out of fashion after the
70s due to relative lack of success,but the paradigm of NAO/AO gives a new
unity to thinking about climate ocean-atmosphere interaction (as fashionable
as it may be).However,the science is still evolving.But all that anybody has
talked about are statistical links and probabilistic forecasts,surely by
looking for linear relations between SST and seasonal climate the error of
popular simplification is being committed.
For a recent overview see-
Hurrell J.W., M. Visbeck, and A. Busalacchi, R. A. Clarke, T. L. Delworth,
R. R. Dickson, W.E. Johns, K.P. Koltermann, Y. Kushnir, D. Marshall, C.
Mauritzen, M. S. McCartney, A. Piola, C. Reason, G. Reverdin, F. Schott, R.
Sutton, I. Wainer, and D. Wright, 2005: Atlantic Climate Variability and
Predictability: A CLIVAR perspective. Journal of Climate: submitted.
http://www.cgd.ucar.edu/cas/jhurrell...livarjan05.pdf


--
regards,
David

add '17' to Waghorne to reply

Waghorn wrote:
I think it's worth pointing out that the regime in the North Atlantic sector
depends on the strength of the polar vortex.When the vortex is strong there
is a single strong zonal jet across the NA,during times of weak vortex there
tends to be two weaker jets-eastern and western in the sector.The
statistical dependence on SST distributions differs entirely for the two
different regimes,

--
regards,
David

add '17' to Waghorne to reply

Also worth noting that the 97 chart shows an 'intense' El Nino which
would have invigorated the polar vortex and reduced the chance of a
negative NAO - IMO.

Also worth noting that the 97 chart shows an 'intense' El Nino which
would have invigorated the polar vortex and reduced the chance of a
negative NAO - IMO.

Yup,el Nino years favour NA zonality and enhance the predictability of the
flow apparently,

--
regards,
David

add '17' to Waghorne to reply

Keith (Southend) wrote:

The more I look into the subject of SST anomalies and cold winters the
more I run into trouble. The link below is what I imagine an ideal SST
anomaly set-up in November for a -ve NOA / easterly set-up in the
winter. The problem is, it's 1997. Winter 1998 was anything but cold. I
know one example proves nothing, but it appeared incredible as it was
the first one I hit on.


https://www.fnmoc.navy.mil/products/...sstanomaly.gif

I can't access that site but I agree with your analysis that the SST anomaly
should have produced more easterlies than usual. However, it doesn't
necessarily follow that the weather will be colder than usual just because
there are more easterly winds than usual. There were some spells in the
97/8 winter that fit the expected pressure anomalies - 2-4th and 15-29th
December, and 18th January to 3rd February - but the flow for some of these
periods was coming around a low-latitude Atlantic low and hence gave mild
wet weather. The only way to check whether the SST anomaly provided good
guidance would be to find mean surface-pressure-anomaly charts for each
winter month.

--
Graham Davis
Bracknell