|"Dawlish" wrote in message
...
On Jan 16, 2:19 pm, "Colin Youngs" wrote:
http://news.bbc.co.uk/2/hi/science/nature/8462890.stm

Colin Youngs
Brussels
|
|Just read it Colin; you beat me to posting it. *))
|
|This is a very balanced piece. I agree with most of it, though at
|times, it mixes seasonal and annual forecasting, which are two
|actually two very different things. In terms of seasonal forecasting,
|I believe they should either abandon it, or explain the experimental
|nature of the forecasts and the likelihood that they may not prove
|correct, far better than they presently do.
|
|Even with the MetO's difficulties in forecasting seasonal weather
|correctly, they are as good as, or better than eveyone else, except
|using hindcasting odds. If anyone feels they are not, then present us
|with the longer-term forecast accuracy of the person, or organisation,
|you think is better. That's all you have to do. At least the MetO are
|prepared to discuss their track record and don't hide it, whilst
|basing their "expertise" on a few remembered successful forecasts and
|forgetting the rest. They all count. They really do.
|
|The real difficulty is that, IMO, *no-one* can forecast seasonal
|weather with confidence which is backed by outcome forecast accuracy
|stats. If there is; show us, don't just bleat about the MetO not being
|able to do it when no-one else can. It's an area at the edge of
|possibility. It's not something from which MetO accuracy should be
|expected.
|

But the Met Office issue a number of "seasonal" forecasts for each season,
so which one do they count when they verify?

To take a very topical example, their original forecast for this current
winter was 50% mild and only 20% cold (these being the upper and lower 33%
of the temperature distribution - the middle 33% being "average"). This
would have been the forecast on which the local highway authorities might
have based their salt stockpiles. The government recommended 6 days supply,
the Met Office were forecasting most likely a mild winter, so why lay in any
more?

The Winter forecast now up on the Met Office site says 45% chance cold - but
this revised forecast was issued when the current (or is it now "recent"?)
cold spell had already started. Will this be the one they use to verify, or
will it be the original? With all respect to the Met Office, anyone can get
a forecast right if they wait for the weather to start happening before
issuing the prediction which counts.

If seasonal forecasts are to be any use, then in my opinion they must be
issued far enough in advance that the information is useful for planning
purposes *and this is the version which verifies*. By all means update them
later on, but now we are just having a discussion so these cannot count for
meaningful statistics.

Until these seasonal forecasts can be shown to have significant skill, they
should be clearly labelled "Experimental" or - like some machines in the old
"penny arcades" - "For amusement only - no prizes". Of course it is
possible that the variability of our local climate and weather is such that
reliable seasonal forecasts cannot be issued with technology likely to be
available any time soon. If this is the case, let's hold our hands up and
be honest about it.

I have no problem with issuing experimental seasonal forecasts for
comparison purposes while developing the necessary technology - but if this
is the case they should be in a separate section of the website and not put
up alongside the short term forecasts which are clearly operational and for
public use.
--
- Yokel -

"Yokel" posts via a spam-trap account which is not read.