"J C-W" wrote in message
...

"Franz Heymann" wrote in message
...

wrote in message
...
On Tue, 23 Sep 2003 18:01:30 +0100, "J C-W"
wrote:


"Franz Heymann" wrote in message
...
The following is true (I'm a sad soul). At the beginning of the
year
I
did
a
small experiment noting forecasts and noting what actually
happened
for
my
city over 3 weeks (I got bored after 3 weeks). I collected each
forecast
for
the following day only, no long range stuff. The three sites
were
Yahooo,
UK Weather.com and the Met Office. Yahoo had something like a 30%
accuracy,
UK Weather.com were about 40% I think and the Met Office came out
tops
with
60 something %. I wish I'd kept the figures now. My conclusion
was,
it's
best to look out of the window :-) And... my goodness are they
getting
paid
for this??!

That means that Yahoo was far and away the best forecaster. If you
rigorously stuck to the opposite of what they said, you would have
had
70%
accuracy.

Franz

Er... somewhat flawed logic - just because it's right for 30% of the
time,
does not mean that the opposite is true for 70% since there are so
many
meteorological variables (i.e. the opposite could be just as wrong).
What
this thread tells us is that for all the technology and super
computer
models being used, the predictions are fundamentally flawed because
they
rely on basic physical principles and ignore chaos theory, quantum
mechanics
and the insight of a deity.

Sadly, I've never knowingly been "au fait" with the insight of a deity
.... especially in relation to weather forecasting. In my experience
he/she/it/they always keep(s) me guessing....!! Now.. quantum chaos I
can relate to!
(;-)

The chaos which makes weather prediction a jocular affair is not
particularly closely connected with quantum effects. It occurs in the
classical weather equations. In fact, it was a study of a classical
weather
model which led to the discovery of chaos.

Franz


You obviously don't subscribe to Prof Sir Roger Penrose's viewpoint on the
undiscovered links between quantum mechanics and macro-scale classical
physics, particularly where those laws break down or fail to be able to
predict observable phenomenon!

Those viewpoints of Penrose do not affect the nature of chaos. Chaos is
associated with most (probably all?) those equations of dynamical systems
which are highly non-linear. Quantum mechanics does not have to be
involved. Newton's equations for planetary systems, which predated quantum
mechanics by a few centuries, can have chaotic solutions.

But we are a long, long way from gardening.......................

There are quite a lot of theorists out there
researching this very thing - a quick search on Google brings a lot of
them
to the fore (e.g. http://amselvam.tripod.com/ ). But, alas, we are
straying
from gardening into another, somewhat off-topic conversation [give myself
a
slapped wrist]....

Two of my colleagues and I were probably the first folk to have investigated
a classical chaotic system before the concept was invented. We were,
however too stupid to recognise what was going on, and ascribed the peculiar
behaviour of our calculations to the results of rounding-off errors in our
mechanical calculator. ( The work predates the availability of solid state
computers by a decade or so)

Urglers, please forgive us for wandering so far from the garden......

Franz