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.