Weather Screen

The Fine Art Of Useless Info

It seems that being not content with a system that worked (even though the Bureau of Meteorology said  that they "...changed the daily rain forecasts on its app following widespread confusion..." - and yet I found it easy to understand) the BoM has changed the rainfall prediction information on their site to a system that's even more opaque. At least, to me. 

Let's face it, most of us look at the Bureau website, select our location, and then look at the resulting page and say "Oh yeah, rain today, '90 per cent chance of rain of between 2 to 4mm' " and while technically as BoM says we'd be wrong, we would still be right enough for our purposes. We'd grab an umbrella on the way out the door. We'd know that it was highly likely to rain today.

It actually, though, made perfect sense to me - it was almost certain it would rain, and somewhere from 2mm up to possibly 4mm. Like anyone else, I'd also leave a margin above the upper figure, and a smaller margin below the lower one. We all know how weather forecasts are 50% BS, 50% inspired guesses, and 50% malicious misdirection, don't we? 😸 

Now, with the new "system" the first digit is 75% likely and the second is 25% likely, and how does that help me work out the actual chance of ANY rain today? If the first figure is non-zero, it'll always mean "Aw geez sport, 75% likely to have rain, why'd you want to know any percentage other than 75%, ya fussy drongo?" 

And now I have NFI - is it REALLY ALWAYS going to be 75% likely to rain, even when the actual likelihood might be 90%? Or 15%? 

A true lesson in how to take something that's worked and has allowed people to make a confident assessment of the day's weather, and rep[lace it with as system where confidence has dropped completely. 

And maybe they know what utter BS most of their weather reports are anyway, and are just wanting to bring their predictions to a point where they seem to be winning: "Look, before, there was a 1 in 10 chance we'd get the rainfall prediction right, now it's much better, it's  1 in 2, either it rains like we said or it doesn't. A quarter of the ti. . . - umm hang on . . . either it rains like we said in the first number or else i- or else. . .  - or else we miss out on the 75% - I think - and so we're wrong three times in fou. . . - hang on, we'll get back to ya." 

Meanwhile, most of us will look at the "Chance Of Rain" line on the graph and ignore the bit we know is BS - the figures themselves... 

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