On Feb 15, 10:11*am, Dave Cornwell wrote:

Nevertheless real forecasters don't have the luxury of missing out days
that are "difficult" as there is an expectation upon them, hence the
occasional poor forecasts.

I've tried saying this in the past. His statistics are not a like-for-
like comparison with any forecasting house statistics. Find me a
forecasting centre that forecasts when it feels like and maybe then a
comparison is worthwhile !! Dressing up a small proportion of
forecasting days when the wind's in the right direction as having 70+%
accuracy is entirely misleading, as far as I'm concerned - heck maybe
I'm wrong.

One actual use in this (apart from telling us all for the umpteenth
time how successful he is) would be in seeing which synoptic
conditions are most prevalent in the 100+ forecasts made - that would
actually be quite helpful.

Richard

In article ,
Dave Cornwell writes:
Whilst I agree with some of the comments as far as I can make out he is
only doing what lots of us do on here do for themselves. Look at the
major ensembles and come to a consensus as to what the weather will be
like based on those. This is part of what Will does, the Met office and
what all forecasters do. The major difference is that they use other
factors, especially when there is poor agreement, to arrive at a
forecast. Dawlish only does a forecast when there is good agreement.
This would inherently lead to a better accuracy. I think he is
basically saying that when the model ensembles are all over the place a
forecast is pointless based on them as it is no more than a guess. This
is a conclusion I have also come to and is borne out in practice.
Nevertheless real forecasters don't have the luxury of missing out days
that are "difficult" as there is an expectation upon them, hence the
occasional poor forecasts.

I agree with all that. If Dawlish wants to do it the way he does, then I
can't see any good reason why he shouldn't. However this does have to be
borne very much in mind when considering his percentage accuracy.

Meanwhile, perhaps by Sod's Law, the 00Z ECMWF now shows a cold easterly
setting in at 10 days, though it's very much an outlier and also has no
support from the GFS (at least not at that timescale). The odds are that
it will have disappeared when we get the 12Z run.
--
John Hall

"The covers of this book are too far apart."
Ambrose Bierce (1842-1914)

On 15/02/2011 09:44, Richard Dixon wrote:
On Feb 15, 8:50 am, wrote:

I did not imply it was was easy, just that the definition of a forecast
is incorrect. I stated that the models generate the forecast and you
wait until there is agreement between them. A forecast is based upon
present and past raw data.

You're running into a brick wall here I'm afraid.

If I were to produce a 10 day forecast based upon model agreement then I
hope that if that were to be successful on my first attempt then I would
have Newton's humility when he wrote in a letter to Robert Hooke "If I
have seen further, it is by standing on the shoulders of giants".

I'll pay some attention to his forecasts when he starts doing them
daily. Like forecasters do.

And if he asks you to "have a try yourself" for having a pop at him,
remind him that he loves to have a pop at the severe weather warnings
and yet doesn't give these a go himself. A man of contradiction.

Richard
Thank you, Richard. I am grateful for the professionals (and ex
professionals) who, so willingly, share their knowledge and expertise on
this group, as well as the many others who provide weather reports.

On Feb 15, 10:26*am, Richard Dixon wrote:
On Feb 15, 10:11*am, Dave Cornwell wrote:

Nevertheless real forecasters don't have the luxury of missing out days
that are "difficult" as there is an expectation upon them, hence the
occasional poor forecasts.

I've tried saying this in the past. His statistics are not a like-for-
like comparison with any forecasting house statistics. Find me a
forecasting centre that forecasts when it feels like and maybe then a
comparison is worthwhile !! Dressing up a small proportion of
forecasting days when the wind's in the right direction as having 70+%
accuracy is entirely misleading, as far as I'm concerned - heck maybe
I'm wrong.

One actual use in this (apart from telling us all for the umpteenth
time how successful he is) would be in seeing which synoptic
conditions are most prevalent in the 100+ forecasts made - that would
actually be quite helpful.

Richard

There aren't any like for like stats at 10 days. Which "forecasting
houses" (whatever they are) produce those stats? You've just made that
up, haven't you? If there are stats; link to them. I'd be really
interested to see them, but there aren't any at 10 days, which is why
I know you've just made that up. Like I have told you many times
before, if it is so easy, have a go - but we know what your reply will
be, as it is just so very predictable. I don't mind that you don't
like what I do, but to always come in when someone else has expressed
their concern is just tiresome to see.

Try it and see how easy it is. It's so easy just to trot out the same
old tired criticism that it is easy and the forecast accuracy doesn't
mean anything, by misrepresenting what I do. Try it; then your irksome
comments might mean something. That's not much to ask. If it is so
easy to do; have a go.

John is absolutely right, actually; you cannot compare what I do, to
what the MetO does. The two are simply not the same and it is never,
ever, me that makes that comparison. It would be worthless for me to
forecast at 10 days, on a daily basis, as the forecasts themselves
would be useless. I can't do that with any accuracy and I'm honest
enough to admit that. You'd never be able to tell which ones had a
good chance of achieving outcome. That's what the MetO does, at 6-15
and 16-30 days and how do you know which of those forecasts, issued
every day, have a likelihood of becoming true? What I do is to
recognise when 10-day charts have a 75%+ chance of being correct and
that is backed by the forecast accuracy stats. Where else can you get
that?

Like I say, if that is easy, have a go yourself. It will be
interesting to see how easy you find it.

Richard Dixon wrote:
On Feb 15, 10:11 am, Dave Cornwell wrote:

Nevertheless real forecasters don't have the luxury of missing out
days that are "difficult" as there is an expectation upon them,
hence the occasional poor forecasts.

I've tried saying this in the past. His statistics are not a like-for-
like comparison with any forecasting house statistics. Find me a
forecasting centre that forecasts when it feels like and maybe then a
comparison is worthwhile !! Dressing up a small proportion of
forecasting days when the wind's in the right direction as having 70+%
accuracy is entirely misleading, as far as I'm concerned - heck maybe
I'm wrong.

Nothing that Dawlish hasn't always been open about of course.
What would be interesting though is not so much the % accuracy but
the % number of days the forecast is attempted. And that can't
be very many, perhaps once every 1-2 months by my reckoning.
Keep maintaining that accuracy rate, whilst increasing the frequency
of forecasts would be more impressive.

If you don't like calling it a forecast then it's an indication of
inter-model correlation at 10 days. Interesting as an excercise
but a world away from being a 'real' forecaster who has to take
a judgment call on the tricky stuff as well. But I'm sure Dawlish
has always acknowledged that.
--
Col

Bolton, Lancashire
160m asl

"Col" wrote in message
...
Richard Dixon wrote:
On Feb 15, 10:11 am, Dave Cornwell wrote:

Nevertheless real forecasters don't have the luxury of missing out
days that are "difficult" as there is an expectation upon them,
hence the occasional poor forecasts.

I've tried saying this in the past. His statistics are not a like-for-
like comparison with any forecasting house statistics. Find me a
forecasting centre that forecasts when it feels like and maybe then a
comparison is worthwhile !! Dressing up a small proportion of
forecasting days when the wind's in the right direction as having 70+%
accuracy is entirely misleading, as far as I'm concerned - heck maybe
I'm wrong.

Nothing that Dawlish hasn't always been open about of course.
What would be interesting though is not so much the % accuracy but
the % number of days the forecast is attempted. And that can't
be very many, perhaps once every 1-2 months by my reckoning.
Keep maintaining that accuracy rate, whilst increasing the frequency
of forecasts would be more impressive.

If you don't like calling it a forecast then it's an indication of
inter-model correlation at 10 days. Interesting as an excercise
but a world away from being a 'real' forecaster who has to take
a judgment call on the tricky stuff as well. But I'm sure Dawlish
has always acknowledged that.
--
Col

Bolton, Lancashire
160m asl

Col, knowing how models behave and how NWP works, I'd still say that Dawlish
is picking out times when analysis differences are small in areas critical
for the UK. In the interests of research Dawlish could have an interesting
database of times when this has occurred. But unfortunately he does not seem
interested in that, otherwise he would supply links to all his forecasts and
times and possibly write a paper in a respected journal! he must have kept
all his forecasts in a private note - surely to goodness?

Will
--

On Feb 15, 8:50*am, PJ wrote:
On 15/02/2011 07:00, Dawlish wrote:





On Feb 14, 10:34 pm, "Will *wrote:
Did he provide them on TWO board before he was banned I wonder?
Just a thought? Is there an archive on TWO?
There certainly has not been 99 forecasts on USW!

Will
--

"Siberian *wrote in message

...

prove it.
post where and when , all links please.

On 14/02/2011 8:12 PM, Dawlish wrote:
. You are welcome to judge it at outcome, as people have been
welcome to judge the 99 previous forecasts:- Hide quoted text -

- Show quoted text -

I'll look forward to you judging it at outcome. Every one of these 99
forecasts has been published on Netweather, TWO and here. I can assure
you that they have been picked over when they've been wrong. It will
be good to recieve any comments on the hundredth.

If you feel it is easy PJ, to forecast at 10 days at any time, all I
ask is that you try it and see how easy it is. I'm sure you'll be
successful, if it is easy. Fair enough?

I did not imply it was was easy, just that the definition of a forecast
is incorrect. I stated that the models generate the forecast and you
wait until there is agreement between them. A forecast is based upon
present and past raw data.

If I were to produce a 10 day forecast based upon model agreement then I
hope that if that were to be successful on my first attempt then I would
have Newton's humility when he wrote in a letter to Robert Hooke "If I
have seen further, it is by standing on the shoulders of giants".
PJ- Hide quoted text -

- Show quoted text -

I doubt whether I'd accept one success as confirmation of ability PJ!
There are some on here that won't accept 79 successes as confirmation
of anything and if there were another 1000, it would still not be
confirmation of anything. Rabbie Burns' spider comes to mind.........
The brick wall, is, of course, in the mind of the poster above, who
feels that no amateur meteorologist should ever proffer anything
different to what the "giants" already do so well and no-one ought
ever to question the wisdom of the ancients, even when that wisdom
means they cannot forecast at 10 days+ with even reasonable accuracy.

and absolute crock of utter lies as usual.
wont answer the question or provide evidence.
WHERE do we find them. Please post proof.
WHO determined they where wrong or right and to come up with those
stats? (no doubt yourself!)

its not forecasting. Its selective betting to make your self look good.
If your forecasted every day, not when it suits you or looks zonaly easy
some on here might give you the time of day.

Instead youve been exposed.

Damned LIES



On 15/02/2011 7:00 AM, Dawlish wrote:
xt -

I'll look forward to you judging it at outcome. Every one of these 99
forecasts has been published on Netweather, TWO and here. I can assure
you that they have been picked over when they've been wrong. It will
be good to recieve any comments on the hundredth.

If you feel it is easy PJ, to forecast at 10 days at any time, all I
ask is that you try it and see how easy it is. I'm sure you'll be
successful, if it is easy. Fair enough?

I'm not familiar with NetWeather and I do not think there is an archive on
TWO board. I may be wrong? Anybody know? I must admit I'd like to know the
dates when the forecasts were prepared to check the synoptic situations as
per Richard D's suggestion. I really do wonder why Dawlish is dodging this
potentially beneficial aspect (for science)? Under what pseudonym did
Dawlish post on TWO board and NetWeather, was it "SW Zephyr" or something?
How can one look if one is not a member of those boards?

Will
--

"Siberian Knight" wrote in message
...
and absolute crock of utter lies as usual.
wont answer the question or provide evidence.
WHERE do we find them. Please post proof.
WHO determined they where wrong or right and to come up with those stats?
(no doubt yourself!)

its not forecasting. Its selective betting to make your self look good.
If your forecasted every day, not when it suits you or looks zonaly easy
some on here might give you the time of day.

Instead youve been exposed.

Damned LIES



On 15/02/2011 7:00 AM, Dawlish wrote:
xt -

I'll look forward to you judging it at outcome. Every one of these 99
forecasts has been published on Netweather, TWO and here. I can assure
you that they have been picked over when they've been wrong. It will
be good to recieve any comments on the hundredth.

If you feel it is easy PJ, to forecast at 10 days at any time, all I
ask is that you try it and see how easy it is. I'm sure you'll be
successful, if it is easy. Fair enough?

On Feb 15, 8:46*pm, "Will Hand" wrote:
I'm not familiar with NetWeather and I do not think there is an archive on
TWO board. I may be wrong? Anybody know? I must admit I'd like to know the
dates when the forecasts were prepared to check the synoptic situations as
per Richard D's suggestion. I really do wonder why Dawlish is dodging this
potentially beneficial aspect (for science)? Under what pseudonym did
Dawlish post on TWO board and NetWeather, was it "SW Zephyr" or something?
How can one look if one is not a member of those boards?

Will
--

"Siberian Knight" wrote in message

...



and absolute crock of utter lies as usual.
wont answer the question or provide evidence.
WHERE do we find them. Please post proof.
WHO determined they where wrong or right and to come up with those stats?
(no doubt yourself!)

its not forecasting. Its selective betting to make your self look good.
If your forecasted every day, not when it suits you or looks zonaly easy
some on here might give you the time of day.

Instead youve been exposed.

Damned LIES

On 15/02/2011 7:00 AM, Dawlish wrote:
xt -

I'll look forward to you judging it at outcome. Every one of these 99
forecasts has been published on Netweather, TWO and here. I can assure
you that they have been picked over when they've been wrong. It will
be good to recieve any comments on the hundredth.

If you feel it is easy PJ, to forecast at 10 days at any time, all I
ask is that you try it and see how easy it is. I'm sure you'll be
successful, if it is easy. Fair enough?- Hide quoted text -

- Show quoted text -

"Pseudonyms" were SW Zephyr and the really crappy "cover up my
identity" one of Paul in Dawlish, Will. Every forecast was
interrogated and dissected, especially the 20-25% that ended up wrong,
right from the start in 2005. You may no longer be able to find them;
as I don't post there any longer, I'm afraid I don't know. I never
expected my experiment and forecasts to go on this long, when I
started 6 years ago and I don't know how long they archive those
posts, but I'm no liar and if you wish to accuse me of that, you'd
have to have clearer evidence than snipy little questions such as
this. You keep no records of your own weekly forecasts and their
accuracy, apart from ad hoc comments from walking friends and site
visitors, I believe? I actually have kept a running record and it is
completely kosher. Are you saying that it's made up and lies Will?
Every forecast on here (31 forecasts since 01/06/2009 - there may have
been some in 2008, but I have no record of those) has been open to
discussion and I return and discuss every one. You have never
discussed any of them and yet you now try to question my records.

Out of those 31 forecasts - all of which I'm happy to email to you -
26 have been correct and 5 incorrect. You can easily access them all
in the archive on here and see that.

You can happily question my methods and I'll happily defend them,
though it appears you would rather discuss in the 3rd person, which
makes discussion rather difficult, but *don't* question my honesty.
It's not in question.