[Paddlewise] (Paddlewise) Weather

"FWIW, the NWS misses its share down here, also -- and for similar
reasons, I
suspect -- not much actual data coming in from the west.  Not as happy a

situation as forecasting air mass behavior in the center of the
continent,
where there is a huge body of information from ground observations in
all
directions."

A Meteorologist named Edward Lorenz, who has been working on computer
and mathematical models for weather prediction for decades, has
developed many insights into understanding the weather on our planet as
a chaotic system.  Some would say that he has proven (in theory) that it
is mathematically speaking impossible to predict the weather accurately,
no matter how detailed the input data, no matter how large the computer,
no matter how complex the mathematical model used.

For refference read "The Essence of Chaos" by Edward Lorenz, U of W
press, Seattle.  According to Lorenz,  discussing current computer
models of worldwide weather , as of late 1991, the worldwide model in
(experimental) use had mushroomed to " a system of 5,000,000 (5 million)
simultaneous equations in as many variables" and was based on " a
horizontal grid of less than 50,000 points, each point must account for
more than 10,000 square kilometers.  Such an area is large enough to
hide a thunderstorm in it's interior."   Even a model of this staggering
complexity only deals with information on temperature, two wind
components, water vapor, and pressure at the surface.  Models such as
this keep leading researches to ever more precisely defined realizations
that when you try to predict the weather you discover that tiny
variations in initial conditions lead, in a very short time, to wildly
varied outcomes.  In a nutshell, the weather IS unpredictable, in any
absolute sense.  There are general tendencies;  with practice we can get
good at guessing what the weather MIGHT be.  This is the nature of
weather, so don't be too hard on the forecaster and never count 100% on
a forecast.

In another passage in Edward Lorenz's book he describes a weather
prediction procedure which "shows signs of becoming the forecast
procedure of the future, when computers have become still more
powerful.  It is known as "Monte Carlo" forecasting.  It takes it's name
from the famous gambling resort . . ."

Nick Lyle

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