Let me throw another thought into the discussion. A -ve winter NAOi
does not automatically guarantee a -ve winter CET. (OK, I know that's
not quite what was offered, but it's what people are expecting). A quick
flick through the individual monthly sea-level pressure charts for the
last 30 years suggests that the relationship between NAOi and CET
may also be something like 2/3 (maybe a little more, but not much).

So, if we accept that figure, the possible outcomes a
44% colder than average with a -ve NAOi
22% colder than average with a +ve NAOi
22% warmer than average with a -ve NAOi
11% warmer than average with a +ve NAOi

So, if the forecast is right for the wrong reason, is it a success?
If it is wrong, but for the right reason, is that a success?

I can see the press release forming as I speak. Either of those will
be a "partial success" or a "qualified success". So there is an 89%
probability that the MO's winter forecast will be spun as a success
or a partial success.

Just try it, Wayne.

Philip Eden


The problem I have with these % probability forecasts, is when the
probability is less than 50%. If it doesn't happen, the forecast was
correct, in that it predicted correctly that something didn't happen.

So, in Winter instead of the forecastor saying "There is a 70% chance it
will stay mild" he/she says "There is a 30% chance of cold weather
returning".

Graham