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

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.

On Feb 15, 6:20*pm, Dawlish wrote:

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.

Are you suggesting that forecasting companies do not perform regular
verification of 10-day (indeed all) forecasts? I'd be very surprised
if that were the case.

Stephen.

On Feb 16, 2:25*pm, Stephen Davenport wrote:
On Feb 15, 6:20*pm, Dawlish wrote:

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.

Are you suggesting that forecasting companies do not perform regular
verification of 10-day (indeed all) forecasts? I'd be very surprised
if that were the case.

Stephen.

It's not made public and therefore it's impossible to verify.

On Feb 16, 2:46*pm, Dawlish wrote:
On Feb 16, 2:25*pm, Stephen Davenport wrote:

On Feb 15, 6:20*pm, Dawlish wrote:

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.

Are you suggesting that forecasting companies do not perform regular
verification of 10-day (indeed all) forecasts? I'd be very surprised
if that were the case.

Stephen.

It's not made public and therefore it's impossible to verify.


Why would verifications be made public? Except the Met Office's,
perhaps.

Stephen.

On 16/02/11 15:09, Stephen Davenport wrote:
On Feb 16, 2:46 pm, wrote:
On Feb 16, 2:25 pm, Stephen wrote:

On Feb 15, 6:20 pm, wrote:

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.

Are you suggesting that forecasting companies do not perform regular
verification of 10-day (indeed all) forecasts? I'd be very surprised
if that were the case.

Stephen.

It's not made public and therefore it's impossible to verify.


Why would verifications be made public? Except the Met Office's,
perhaps.

Stephen.

1. To demonstrate the skill of their forecasts to the public.

2. To demonstrate that they have nothing to hide by being open with
their forecast skill.

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
--