On Oct 20, 1:03*pm, Dawlish wrote:
On Oct 19, 11:50*pm, Robin Nicholson





wrote:
On Mon, 19 Oct 2009 03:28:11 -0700 (PDT), Dawlish
wrote:

Looking like this dry spell will end and not return for a while. 4
consecutive gfs runs now showing Atlantic conditions across the UK for
the forseeable future. A large Scandinavian block may delay the
progress of those lows and fronts somewhat, keeping eastern areas of
the UK drier, but that looks as if it may decline and allow in
Atlantic weather further by T240.

Interesting - I was forming the impression that the west to east shift
was not going to falter as I thought it might a few days ago. I see
Willo is going to review the end of the week midweek. Not concerned
really as I am staying on the Norfolk coast next week and it can blow
a bit if it wants. I am definitely 'chilling out' over there.

R

Hilton

Something possibly brewing for Sunday. Both the ECM and the gfs centre
a deep low over the UK with some strong winds wrapped around it. Still
early for any detail and height rises to the east may well emasculate
this possible storm completely, but it's there at 5 days.- Hide quoted text -

- Show quoted text -

Still a chance of some windy weather for England on Sunday, but more
than that, there is a good chance of some mild weather over the
weekend, with temps up to 18C. Some warm nights too, with temps not
dropping below 10C should give a lift to the CET. Not much need for
the central heating this weekend!

On Oct 21, 7:13*pm, Dawlish wrote:
On Oct 21, 6:48*pm, "Col" wrote:

"Dawlish" wrote in message

....

It's just not there. The 06z sinks the high!
http://www.wetterzentrale.de/pics/Rtavn2402.png

But back again on the 12z.....
--
Col

Bolton, Lancashire
160m asl

Very true Col! The 06z *was probably an outlier, but the interruption
to the consistency begs a couple more runs and agreement from the ECM
before a forecast.

ECM 12z agrees with the gfs and shows no change from the 00z. See what
the output is like tomorrow morning for the possibility of a forecast.
A mild, S/SE flow, with a scandinavian block, is a distinct
possibility at T240.

On Oct 21, 10:07*pm, Dawlish wrote:
On Oct 21, 8:30*pm, "Norman" wrote:





John Hall wrote:
In article ,
*Will Hand writes:

"Col" wrote in message news:4NSdnYGhC8U4zkL
...

"Dawlish" wrote in message

...
On Oct 21, 6:48 pm, "Col" wrote:
"Dawlish" wrote in message

...

It's just not there. The 06z sinks the high!
http://www.wetterzentrale.de/pics/Rtavn2402.png

But back again on the 12z.....
--
Col

Bolton, Lancashire
160m asl

Very true Col! The 06z *was probably an outlier, but the interruption
to the consistency begs a couple more runs and agreement from the ECM
before a forecast.

Yes, I am beginning to understand how you approach these10
day forecasts. It's all about consistency and ultimately 'confidence'.
If you get a run that suddenly goes against what the recent runs
have been showing then that confidence is shaken and it takes a
few more runs showing the original sceanario to get that confidence
back to it's original level.
That run could be an outlier, but then it could depict what the
weather actually does!
-- *Col

Of course professional forecasters don't have that luxury. Customers
want forecasts and they want them now!

But they do have the big advantage of access to the ensembles, whereas I
believe that Dawlish uses only the production runs. Thus he can't tell
whether or not a particular production run is likely to be an outlier
other than by relying on consistency between models and from one run to
the next.

But why not look at the ensembles? The GFES ensembles are widely promulgated on
the net.

Norman- Hide quoted text -

- Show quoted text -

Mainly because, at 10 days, ensembles are a waste of time. At that
distance, the error in every run is so great that you can't trust what
you are seeing with the spread. It tends towards randomness. If
ensemble prediction was the answer, we'd have better accuracy at 10
days, but the outcomes show that ensembles are certainly not the
answer. Neither are they "a part of the mix" because the "mix" doesn't
work either. In fact, nothing works at 10 days on a regular basis; if
it did, someone would be able to demonstrate accuracy on a daily basis
and they can't. That is why I only forecast when my technique suggests
I will have at least 75% success and over 74 forecasts, that is the
success rate that I can demonstrate using that method. That has to
count.

I take entirely what Will says about public expectation and he is
completely right. The public expect forecasts every day at 10 days and
more. If it wasn't on the website, there would be complaints galore!
Fortunately, the public don't keep any accuracy records and the MetO
can say just about what they want in the 6-15 day forecasts, with no
comeback whatsoever - everyone has forgotten what they said at
outcome! Well, almost everyone *)). Who tracks the accuracy of that
6-15 day forecast? The MetO don't; NOAA don't and I would suggest that
it is impossible to do that from anyway from the dearth of information
that it contains.

At 10 days we are presently beyond the limits of forecasting with
accuracy on a daily basis. Simple as that.- Hide quoted text -

- Show quoted text -

"Will Hand" wrote in message
...

"Col" wrote in message
...

"Dawlish" wrote in message
...
On Oct 21, 6:48 pm, "Col" wrote:
"Dawlish" wrote in message

...

It's just not there. The 06z sinks the high!
http://www.wetterzentrale.de/pics/Rtavn2402.png

But back again on the 12z.....
--
Col

Bolton, Lancashire
160m asl

Very true Col! The 06z was probably an outlier, but the interruption
to the consistency begs a couple more runs and agreement from the ECM
before a forecast.

Yes, I am beginning to understand how you approach these10
day forecasts. It's all about consistency and ultimately 'confidence'.
If you get a run that suddenly goes against what the recent runs
have been showing then that confidence is shaken and it takes a
few more runs showing the original sceanario to get that confidence
back to it's original level.
That run *could* be an outlier, but then it *could* depict what the
weather actually does!
--
Col

Of course professional forecasters don't have that luxury. Customers want
forecasts and they want them now!

Will
--


Come on Will: Dawlish believes a Medium Range Forecast is one given by Derek
Acorah.

Any one 'ere knows a name beginning with P or PG maybe it was PG tips,
anyone 'ere fancy a cuppa? Hold a minute I can feel a message comin'
through; who is it Sam opps sorry Sam goes 'ome a six


Ey Up whats that? The winter forecast is behind the clock on mantelpiece.

On Oct 21, 10:57*pm, Dawlish wrote:
On Oct 21, 10:07*pm, Dawlish wrote:



On Oct 21, 8:30*pm, "Norman" wrote:

John Hall wrote:
In article ,
*Will Hand writes:

"Col" wrote in message news:4NSdnYGhC8U4zkL
...

"Dawlish" wrote in message

...
On Oct 21, 6:48 pm, "Col" wrote:
"Dawlish" wrote in message

...

It's just not there. The 06z sinks the high!
http://www.wetterzentrale.de/pics/Rtavn2402.png

But back again on the 12z.....
--
Col

Bolton, Lancashire
160m asl

Very true Col! The 06z *was probably an outlier, but the interruption
to the consistency begs a couple more runs and agreement from the ECM
before a forecast.

Yes, I am beginning to understand how you approach these10
day forecasts. It's all about consistency and ultimately 'confidence'.
If you get a run that suddenly goes against what the recent runs
have been showing then that confidence is shaken and it takes a
few more runs showing the original sceanario to get that confidence
back to it's original level.
That run could be an outlier, but then it could depict what the
weather actually does!
-- *Col

Of course professional forecasters don't have that luxury. Customers
want forecasts and they want them now!

But they do have the big advantage of access to the ensembles, whereas I
believe that Dawlish uses only the production runs. Thus he can't tell
whether or not a particular production run is likely to be an outlier
other than by relying on consistency between models and from one run to
the next.

But why not look at the ensembles? The GFES ensembles are widely promulgated on
the net.

Norman- Hide quoted text -

- Show quoted text -

Mainly because, at 10 days, ensembles are a waste of time. At that
distance, the error in every run is so great that you can't trust what
you are seeing with the spread. It tends towards randomness. If
ensemble prediction was the answer, we'd have better accuracy at 10
days, but the outcomes show that ensembles are certainly not the
answer. Neither are they "a part of the mix" because the "mix" doesn't
work either. In fact, nothing works at 10 days on a regular basis; if
it did, someone would be able to demonstrate accuracy on a daily basis
and they can't. That is why I only forecast when my technique suggests
I will have at least 75% success and over 74 forecasts, that is the
success rate that I can demonstrate using that method. That has to
count.

I take entirely what Will says about public expectation and he is
completely right. The public expect forecasts every day at 10 days and
more. If it wasn't on the website, there would be complaints galore!
Fortunately, the public don't keep any accuracy records and the MetO
can say just about what they want in the 6-15 day forecasts, with no
comeback whatsoever - everyone has forgotten what they said at
outcome! Well, almost everyone *)). Who tracks the accuracy of that
6-15 day forecast? The MetO don't; NOAA don't and I would suggest that
it is impossible to do that from anyway from the dearth of information
that it contains.

At 10 days we are presently beyond the limits of forecasting with
accuracy on a daily basis. Simple as that.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

gfs shows high pressure over the UK (with a very wintry looking plunge
over eastern Europe towards the Balkans - likely not to happen)
whereas the ECM now shows the Atlantic reinvigorated. Nothing that
shows consistency, or agreement at 10 days. Unsettled out to the
middle of next week, for sure, but more chance of that unsettled
weather being stalled by a block to the east and a then a build of
pressure towards the UK. It's a generally mild outlook and the next 9
days may well see the CET move into positive territory for October
(-0.4C to the 21st C/O Philip http://www.climate-uk.com/). At 10 days,
however, it's a guessing game again.