"Coby Beck" wrote:

"Fran Manns" wrote in message
. ..

When the 5 day forecast is flawed, how can one trust the 100 year
forecast.

Weather and climate are not the same thing, this is a very basic fact.

An easy way to understand the difference: one can never predict with
certainty that it will rain or shine tomorrow. However, even a child can
predict that summer folows spring follows winter. I can tell you with
certainty that it will always be around 30oC in Managua, Nicaragua, dry half
the year, wet the other half. I can tell you with certainty that winter in
Vancouver will be very overcast and rainy but summer will be substantially
warmer and sunnier.

The reason is the difference between long term patterns and short term
chaotic fluctuations. Another good analogy: you can not predict how far up
the beach the next 10 waves will come, but you can prdect the level of the
next 10 tides.

Ahem.. .. subject to the caveats re pressure and wind I mentioned a
few days ago. :-) In a little more detail:

Published tidal predicition assume a standard barometric pressure of
1017 millibars and are issued on the basis of no particular local
weather patterns. A "high" of 34 millibars over the standard will
depress both High and Low water by 1 foot. If the pressure drops the
same amount below standard, High and Low water will be raised by 1
foot - and pro rata for pressures beyond these, or between them.

Wind's not so easy to calculate!

So, strictly speaking, you can only predict the tidal height if you
know what the weather conditions are going to be in advance. So, 10
tides, approx 5 days, is pushing it a bit! :-)

In short: no inference whatsoever can by drawn about the accuracy climate
models from the accuracy of weather prediction.

But I take your point.

--
Jeff. Ironbridge, Shrops, U.K.
(remove the x..x round jackfield for return address)
and don't bother with ralf4, it's a spamtrap and I never go there..

.... "There are few hours in life more agreeable
than the hour dedicated to the ceremony
known as afternoon tea.."

Henry James, (1843 - 1916).