Neither the ECM, nor especially the gfs, have demonstrated consistency
over the last few days - actually neither model has shown consistency
at 10 days since a few days after I issued the high pressure forecast
back on 3rd Oct - though presently, both have a measure of agreement
on low pressure being anchored to the west of the UK and the high
having drifted east, producing a mild and faily strong southerly flow
over the UK at T240.

Then comes GEM showing consistent high pressure right out to the last
third of October with a fat anticyclone sitting right over the UK on
the 21st Oct and low pressure nowhere to be seen! An enormous contrast
to the other two models.

all on wetterzentrale: http://www.wetterzentrale.de/topkarten/fsgemeur.html

Nothing this morning that makes me think that it is possible to
forecast with any expectation of 10-day accuracy and the MetO seems to
feel that way with this one sentence for the whole 8-day period
following 18th Oct. "Then during the second week unsettled weather
with rain or showers and strong winds is expected to gradually extend
southeastwards to all areas". - Meaning (I think) that the high
pressure will slowly decline, somehow. Probably safe territory and the
best bet. If the gfs and ECM are still showing a similar set-up
overnight tonight, that would satisfy my perameters for a 10-day
forecast, but I'm not at all confident that they will.

One of the most difficult things in forecasting at 10 days is
realising when the conditions are not right for forecasting with
accuracy. 2 days ago, all my criteria were almost fulfilled and from
the models, I'd have been forecasting the continuation of high
pressure had the ECM not broken ranks with the gfs. The MetO is forced
by public expectation to forecast something at this distance, but the
MetO knows full well the enormous difficulties of achieving any kind
of acceptable accuracy at anything over a week; hence the paltry 200
words of the 6-15 day forecast and the lack of accuracy records at
this distance. No blame there - that's just a statement of what is
possible and what isn't possible, at present.

On Oct 11, 9:53*am, Dawlish wrote:

Nothing this morning that makes me think that it is possible to
forecast with any expectation of 10-day accuracy and the MetO seems to
feel that way with this one sentence for the whole 8-day period
following 18th Oct. "Then during the second week unsettled weather
with rain or showers and strong winds is expected to gradually extend
southeastwards to all areas". - Meaning (I think) that the high
pressure will slowly decline, somehow. Probably safe territory and the
best bet. If the gfs and ECM are still showing a similar set-up
overnight tonight, that would satisfy my perameters for a 10-day
forecast, but I'm not at all confident that they will.

And to illustrate that point, the 12z gfs shows high pressure never
leaving our shores out to T264! See if the 12z ECM holds its ground
this evening.

"Dawlish" wrote in message
...
Neither the ECM, nor especially the gfs, have demonstrated consistency
over the last few days - actually neither model has shown consistency
at 10 days since a few days after I issued the high pressure forecast
back on 3rd Oct - though presently, both have a measure of agreement
on low pressure being anchored to the west of the UK and the high
having drifted east, producing a mild and faily strong southerly flow
over the UK at T240.

Then comes GEM showing consistent high pressure right out to the last
third of October with a fat anticyclone sitting right over the UK on
the 21st Oct and low pressure nowhere to be seen! An enormous contrast
to the other two models.

all on wetterzentrale:
http://www.wetterzentrale.de/topkarten/fsgemeur.html



If it proves to be that former is that the end of your Indian Summer?

On Oct 11, 4:50*pm, "Lawrence Jenkins" wrote:
"Dawlish" wrote in message

...





Neither the ECM, nor especially the gfs, have demonstrated consistency
over the last few days - actually neither model has shown consistency
at 10 days since a few days after I issued the high pressure forecast
back on 3rd Oct - though presently, both have a measure of agreement
on low pressure being anchored to the west of the UK and the high
having drifted east, producing a mild and faily strong southerly flow
over the UK at T240.

Then comes GEM showing consistent high pressure right out to the last
third of October with a fat anticyclone sitting right over the UK on
the 21st Oct and low pressure nowhere to be seen! An enormous contrast
to the other two models.

all on wetterzentrale:
http://www.wetterzentrale.de/topkarten/fsgemeur.html

If it proves to be that former is that the end of your Indian Summer?- Hide quoted text -

- Show quoted text -

Back to low pressure dominance on the 12z! the gfs is not showing a
great deal of consistency!

Lawrence, I didn't know the Indian summer was mine! Pray tell me when
I forecast an Indian summer, do.

"Dawlish" wrote in message
Lawrence, I didn't know the Indian summer was mine! Pray tell me when
I forecast an Indian summer, do.


Hmmm maybe I'm old fashioned but ...............

"Are we seeing the beginnings of model consistency and agreement for an
Indian summer? (whatever that actually means!)

Both the ECM and the gfs are looking to build high pressure after this
shock of cool, windy and eventually (for us in the south) wet weather.
As Will says, the drought ought to be broken for many next week and
gales will come as an unwelcome shock in the north tomorrow. I say
unwelcome shock, as trees are still in full leaf and a few might end
up in gardens and across roads in the north with those steep pressure
gradients.

Beyond that - back to calm and settled with the chance of some warm
weather out towards mid October with 20C+ in the south? Watch this
space."

On Oct 11, 5:33*pm, Dawlish wrote:
On Oct 11, 4:50*pm, "Lawrence Jenkins" wrote:





"Dawlish" wrote in message

...

Neither the ECM, nor especially the gfs, have demonstrated consistency
over the last few days - actually neither model has shown consistency
at 10 days since a few days after I issued the high pressure forecast
back on 3rd Oct - though presently, both have a measure of agreement
on low pressure being anchored to the west of the UK and the high
having drifted east, producing a mild and faily strong southerly flow
over the UK at T240.

Then comes GEM showing consistent high pressure right out to the last
third of October with a fat anticyclone sitting right over the UK on
the 21st Oct and low pressure nowhere to be seen! An enormous contrast
to the other two models.

all on wetterzentrale:
http://www.wetterzentrale.de/topkarten/fsgemeur.html

If it proves to be that former is that the end of your Indian Summer?- Hide quoted text -

- Show quoted text -

Back to low pressure dominance on the 12z! the gfs is not showing a
great deal of consistency!

Lawrence, I didn't know the Indian summer was mine! Pray tell me when
I forecast an Indian summer, do.- Hide quoted text -

- Show quoted text -

The last 3 gfs operational runs have shown good agreement with the ECM
that this nascent spell of fine weather will be gone by T240 and by
then we'll be in a much more unsettled regime. Give me another couple
of runs today and I'll have the 75%+ confidence I need to forecast.