"Graham P Davis" wrote in message
...
On 05/03/10 12:48, Will Hand wrote:
Didn't Will say that it would change as we approach the Spring
Equinox, with the Sun moving North of the Equator it would start to
drag the Jet Stream away from its Winter holiday in Morocco?

=========

I did Bonos, a long time ago now as well!
I stand by it still.

And I'll stick to the SST anomalies keeping it down south for the most
part. Mind you, the anomalies are said to have less effect during the
summer so that may be some small crumb of comfort.


Graham, can you explain why such a relatively small patch of cold water (40N
40W) on the global scale can affect the whole NH dynamics at 9Km and above?
Might it not be that the NH SST anomalies are symptomatic rather than
causal?

Will
--

On 05/03/10 15:16, Will Hand wrote:

"Graham P Davis" wrote in message
...
On 05/03/10 12:48, Will Hand wrote:
Didn't Will say that it would change as we approach the Spring
Equinox, with the Sun moving North of the Equator it would start to
drag the Jet Stream away from its Winter holiday in Morocco?

=========

I did Bonos, a long time ago now as well!
I stand by it still.

And I'll stick to the SST anomalies keeping it down south for the most
part. Mind you, the anomalies are said to have less effect during the
summer so that may be some small crumb of comfort.


Graham, can you explain why such a relatively small patch of cold water
(40N 40W) on the global scale can affect the whole NH dynamics at 9Km
and above? Might it not be that the NH SST anomalies are symptomatic
rather than causal?


I think I've already answered this in an earlier response to one of your
queries on this subject. Also, it's hardly a small patch of water.
Perhaps you'd be better off going to the horse's mouth and checking on
the work by Lamb and Ratcliffe back in the 60s and 70s.


--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."

SNIP

Might it not be that the NH SST anomalies are symptomatic rather than
causal?

Will


I rather think so.

Whilst not having a deep scientific knowledge of such things, I've had
an interest in North Atlantic SST anomalies for decades, and I have
little doubt the the prevailing synoptic situation controls SSTs
rather than the reverse.

Of course, it's not wholly one way, but just looking at ast SST
anomalies & related archived synoptic charts tells you a lot.

However, I do wonder if the large reduction of arctic ice in 2007 has
played some part in the last 3 poor (by recent standards) summers.

Graham
Penzance

On Mar 5, 4:14*pm, Graham P Davis wrote:
On 05/03/10 15:16, Will Hand wrote:







"Graham P Davis" wrote in message
...
On 05/03/10 12:48, Will Hand wrote:
Didn't Will say that it would change as we approach the Spring
Equinox, with the Sun moving North of the Equator it would start to
drag the Jet Stream away from its Winter holiday in Morocco?

=========

I did Bonos, a long time ago now as well!
I stand by it still.

And I'll stick to the SST anomalies keeping it down south for the most
part. Mind you, the anomalies are said to have less effect during the
summer so that may be some small crumb of comfort.

Graham, can you explain why such a relatively small patch of cold water
(40N 40W) on the global scale can affect the whole NH dynamics at 9Km
and above? Might it not be that the NH SST anomalies are symptomatic
rather than causal?

I think I've already answered this in an earlier response to one of your
queries on this subject. Also, it's hardly a small patch of water.
Perhaps you'd be better off going to the horse's mouth and checking on
the work by Lamb and Ratcliffe back in the 60s and 70s.

--
Graham P Davis, Bracknell, Berks., UK. *E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."- Hide quoted text -

- Show quoted text -

I'm sure that there is something that can explain the end of this
winter cold (when it comes, for all areas and notwithstanding the fact
that spring has definitely arrived on the south coast of Devon, for
now, at least!) but I'm not at all sure either of you are correct in
your different reasons - though both probably have some part to play.
If one of you was correct in this, or if Lamb and Ratcliffe were
correct, the MetO would have a far better record in seasonal
forecasting than it has. Forecasting that it is highly likely to get
warmer as winter turns into spring seems a bit self evident Will.
Also, that really is a relatively small patch of the North Atlantic
Graham to be affecting our weather so greatly for 3 months. Could it
really have prevented cyclogenesis and a westerly flow across to us?

The SSW event doesn't seem to have played a great part, though it
occurred at a similar time. However it has now decayed and we still
have northern blocking and easterlies, at least in southern England.
The amount of ice to our north has had little effect, as it has been
at record lows through the winter when our weather has been colder
than average and much colder than in recent years. SSTs in late spring/
early winter in the North Atlantic didn't help the MetO at all to
predict the sign of the NAO at all this year. Teleconnections and
pattern matching to previous winters may have helped this time, but
the track record of both pattern matching afficionados and
teleconnection seers is very poor. ENSO may well have played a part,
but the research points to an El Nino year being linked to colder
weather in NW Europe in late winter/early spring and not from early
December onwards. Solar activity - the jury has not even taken the
stand, never mind retired.

So what did actually cause our colder winter? We know that the
southerly Jet did, but that is almost certainly a symptom of something
else, and not a cause. It is a very difficult and under-researched
subject IMO and if the MetO really wish to resume seasonal forecasting
at some stage, more money is going to have to be targeted at it.

Here's the latest charts
http://www.osdpd.noaa.gov/data/sst/a...t.3.4.2010.gif

Whilst it has been unbroken sunshine here in South Devon, I would
debate whether you could say that Spring has arrived?

I once recall Philip Eden, correct me if I'm wrong, saying that a good
indicator of when Spring has arrived is when the average daily
temperature exceeds +6.0°c

Last night in my Teignmouth back garden the temperature fell to -2.6°c
The maximum today is a around +8.9° http://www.greatweather.co.uk/teignmouth/current.html
Therefore the mean daily average was a chilly +3.15°c


Using the official Teignmouth weather data from 1st March, the mean
average temperature in Teignmouth for March is currently only +4.67°c
http://www.teignbridge.gov.uk/index....KEN=29262 693

Date,Min,Max
01/03/2010,+1.0,+8.7
02/03/2010,-0.2,+8.9
03/03/2010,+2.0,+8.9
04/03/2010,+2.2,+6.9
05/03/2010,-0.2,+8.5

I would therefore say we are currently still in Winter based on
temperature, rather than Spring.

I appreciate the standard definiation of the seasons is;

Winter, Dec,Jan,Feb
Spring, Mar,Apr,May

On 05/03/10 16:45, Dawlish wrote:
On Mar 5, 4:14 pm, Graham P Davis wrote:
On 05/03/10 15:16, Will Hand wrote:







"Graham P Davis" wrote in message
...
On 05/03/10 12:48, Will Hand wrote:
Didn't Will say that it would change as we approach the Spring
Equinox, with the Sun moving North of the Equator it would start to
drag the Jet Stream away from its Winter holiday in Morocco?

=========

I did Bonos, a long time ago now as well!
I stand by it still.

And I'll stick to the SST anomalies keeping it down south for the most
part. Mind you, the anomalies are said to have less effect during the
summer so that may be some small crumb of comfort.

Graham, can you explain why such a relatively small patch of cold water
(40N 40W) on the global scale can affect the whole NH dynamics at 9Km
and above? Might it not be that the NH SST anomalies are symptomatic
rather than causal?

I think I've already answered this in an earlier response to one of your
queries on this subject. Also, it's hardly a small patch of water.
Perhaps you'd be better off going to the horse's mouth and checking on
the work by Lamb and Ratcliffe back in the 60s and 70s.

--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."- Hide quoted text -

- Show quoted text -

I'm sure that there is something that can explain the end of this
winter cold (when it comes, for all areas and notwithstanding the fact
that spring has definitely arrived on the south coast of Devon, for
now, at least!) but I'm not at all sure either of you are correct in
your different reasons - though both probably have some part to play.
If one of you was correct in this, or if Lamb and Ratcliffe were
correct, the MetO would have a far better record in seasonal
forecasting than it has.

That assumes they still use it. My impression was that (a) it had been
forgotten about and (b) it was old science that hadn't been proved
recently (but hadn't been disproved either) and therefore not worth
bothering about.

Forecasting that it is highly likely to get
warmer as winter turns into spring seems a bit self evident Will.
Also, that really is a relatively small patch of the North Atlantic
Graham to be affecting our weather so greatly for 3 months. Could it
really have prevented cyclogenesis and a westerly flow across to us?

Small? It extends right across the Atlantic! Based on the first signs of
a cooling in the region, I did warn back in November that we might see
an easterly winter. Also, the seasonal forecast from Netweather included
a forecast pressure chart based on the SST anomalies. I reckon this was
a pretty good forecast of the pattern and, for good measure, forecast
the jet stream would be displaced southwards.


--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."

On 05/03/10 16:36, Graham Easterling wrote:
SNIP

Might it not be that the NH SST anomalies are symptomatic rather than
causal?

Will


I rather think so.

Whilst not having a deep scientific knowledge of such things, I've had
an interest in North Atlantic SST anomalies for decades, and I have
little doubt the the prevailing synoptic situation controls SSTs
rather than the reverse.

Of course synoptic patterns have an effect on SSTs. But it has been
shown that there is a statistical link between one month's SST pattern
and the following month's pressure pattern. As I've pointed out before,
there are good reasons why this this should be so.


Of course, it's not wholly one way, but just looking at ast SST
anomalies & related archived synoptic charts tells you a lot.

In a way, I guess that's how it all started back in the 60s. Only they
did more than look at charts and went on to prove the relationship
scientifically.


However, I do wonder if the large reduction of arctic ice in 2007 has
played some part in the last 3 poor (by recent standards) summers.


Dunno! I can't quite see why it should make a difference but I wouldn't
rule it out. I can see that this winter wasn't as cold as it might have
been, and I reckon the low ice cover in the Greenland and Barents Seas
has been at least partly responsible for that.


--
Graham P Davis, Bracknell, Berks., UK. E-mail: newsman not newsboy
"I wear the cheese. It does not wear me."

In article
,
Bonos Ego writes:
I once recall Philip Eden, correct me if I'm wrong, saying that a good
indicator of when Spring has arrived is when the average daily
temperature exceeds +6.0°c
snip

Yep. Presumably the soil temperature in the top inch or two will be
close to the average daily air temperature, and soil temperature is what
determines when many (most?) plants start growing.
--
John Hall
"Acting is merely the art of keeping a large group of people
from coughing."
Sir Ralph Richardson (1902-83)