For an organisation that’s supposed to be charged with upholding the standards of measuring climate data laid down by the WMO, I think it’s irresponsible of them to be using wind speed data from the Needles (even if it is to justify a storm they’ve just named), without stating that the gust of 97 mph was from an unofficial site with a non-standard exposure. Many people may not realise the severe exposure of the anemometer tower there, which sits atop a 393 foot sheer chalk cliff. Sunday’s 97 mph gust was the most recent case in point, but as you’ll see later in the article, gusts from there are used almost every time a named storm affects the south coast.
I thought I would take a closer look at what the WMO actually said about the siting of an anemometer mast in their guidance on site classification. Surprisingly the word cliff, mountain or lighthouse never gets a mention, then I read that changes of altitude either positive, or negative are considered obstacles, and then the penny dropped. Using these guidelines it’s easy to see why the exposure at the Needles makes it a class 5 site. In fact to be a class 1 site (the ideal), the anemometer mast should be sited at least 30 times the height of the cliff away, in the case of the Needles that would be around 3.6 km away from the edge of 120 metre sheer cliff face.
Never let the facts get in the way of a good story
As I said earlier, extreme gusts at the Needles feature heavily in many of the Met Office reports on named storms on their website, and the reason for that is simple, gusts there are often 10% higher than anywhere else! What would the headline writers at the Daily Mail or Daily Express do without them! I don’t think the Met Office should stop using them, I just think that they should label them as being either non-standard or unofficial. Here is a just a flavour of how often the Met Office press team have relied on wind gusts from the Needles in past headlines and stories.