whisky-dave wrote:

On Monday, 14 August 2017 15:15:33 UTC+1, Dave W wrote:
"whisky-dave" wrote in message
...
On Saturday, 12 August 2017 22:07:34 UTC+1, James Wilkinson Sword wrote:
On Tue, 08 Aug 2017 10:46:31 +0100, whisky-dave
wrote:

On Monday, 7 August 2017 19:53:47 UTC+1, James Wilkinson Sword wrote:
On Fri, 04 Aug 2017 16:58:59 +0100, whisky-dave
wrote:

On Friday, 4 August 2017 15:05:41 UTC+1, James Wilkinson Sword
wrote:
On Fri, 04 Aug 2017 11:31:24 +0100, whisky-dave
wrote:

If a forecaster uses probabilities, he's guessing.

That's what forcasting is just working out probabilities of what
is most likely to happen.

And until that probability is near 0% and 100%, there's no point.

Yes there is just like betting.
If there was a 50% chance of you winning the lottery by placing a £1
bet then would you place the bet ?
But remmeber yuor stats dum**** it's 50% isn't it.
You either win or you don't just two outcomes.

No point in betting on something if there's a 50% chance of winning £1
and a 50% chance of losing £1. Which is what you get with weather.
Thats why just a % figure is pretty useless on it's own.

Tell that to the ****ty weather websites.
https://weather.com/en-GB/weather/to...p=c&par=google
"Min 8C, 10% chance of rain, partly cloudy, wind 10-15km/h."

Having problmes understanding it are you.

Today it says there;s a 30% chance of a few showers, that;s not the same as
30% change of a tornado. Humidity 81% does that mean thre;sa a 81% chance of
humidity ?
So there's 19% chance of no humitidy is that it ?



The famous storm of 1987 in the UK had a probability of 20% that
hurricane force winds would hit the south coast.

So they were **** at predicting it.

No there was a 20% chance of it happening that is 1 in 5
\plenty of peole place bets on horses with far less likely to win but
they still do it.
There's the national lottery something like 14 million to 1 on
winning.

If someone tells you there's a 20% chance of something happening, you
will assume it probably won't happen. Yet it did.

I wouldn't assume that with a 20% chance. Only someone that didn't
understand what they were reading might do though.

If I said there was a 20% chance of you winning the lottery, would you go
out and celebrate?

No but I'd go out and buy a ticket and would thibnk it is more likely that;s
I'd win than having the standard chance of 1 in 14 million or so.

---------------------------------------------
Percentage of what? I would imagine that 20% of viewers would get rain and
80% wouldn't.

Where percentage is a probability. It's NOT 20% of viewers. It's a 1 in 5
chance that it will rain. In the website above it said showers so a 20%
chance of showers. I do realise that for the dumb it;s really difficult
those accessing the page fropm pluto and will see the 20% chance and ask
if teh rain will be water or methane or nitrogen, ut thatf is theiur
problem they will never understand the weather on earth either.

In the case of showers I think it is more like a 100% chance of showers
occurring in the broad geographical area under consideration, with a 20%
chance of any given location being affected by them. With weather
fronts I suspect if it is a different type of calculation, relating to
their probable speed, direction and wetness.





--

Roger Hayter