As we get nearer the weekend, our fascination with the weather forecast grows. Last week, we were promised a fine Friday and Saturday with rain and storms on the Sunday. The promise of sunshine was a boost to the system - finally some nice weather! Friday was a pleasant enough day - some long sunny intervals and slightly warmer temperatures, so when Saturday dawned uniformly grey and cold, we were devastated. Seasonal Affected Disorder wasn't in it - we were downright depressed.
There is the potential for a similar scenario this week as well. Meteo France are predicting a hot sunny Friday and Saturday and a hot Sunday though with the potential for some storms - the fact we were so badly let down last weekend makes this a cruel forecast. Will they be right and we will have some summer at last, or will the clouds crawl in/down from the Channel/Atlantic and another depression (meteorological and mood-wise) sweep our household?
In hypothesis testing, there are type I and type II errors - the one being the chance of rejecting a hypothesis when it is in fact right, and the other being the chance of accepting a hypothesis when it is in fact wrong. Last week, we believed the forecasters, thinking they had enough information to get it right, but they got it wrong (type II in my book). This week we are suspicious and won't believe in nice weather until we have got just a little bit sun burnt, and have gone back to summer clothes from winter jumpers and long trousers (could this be a type I error on our part?).
In this instance, which error type is worse? The disappointment last weekend at poor weather was immense and seemed to be almost physically painful, as we had set our hearts on one weather pattern as predicted by the weather boffins. If we have the same disappointment this weekend, I will have to avoid the "contact us" bit of their website, or I could be in serious trouble. But would it have been worse if they had predicted bad weather all along, giving gloom in anticipation, and they had been right? Would I have felt so bad? I don't think so. If they had predicted poor weather and we had had a nice weekend, I would have been pleasantly surprised and felt happier about the world.
The nature of the forecast is therefore a factor in our feelings about whether type I or type II errors are more acceptable as far as the weather is concerned. Of course this assumes that there is no cash or danger attached to getting the answer wrong. In my days with British Gas, not having a reliable weather forecast to ensure enough gas in the system for diurnal requirements could cost money and even lives (and jobs for those who got the forecast wrong), and forecasting for the electricity grid system was even more sensitive than that, as it needed to respond to changes in demand within the hour.
Weather forecasting for the masses doesn't need that level of detail or accuracy and the weather is a chaotic and unpredictable system, so why do I get so upset about it? Because in a year like 2007, the promise of sunshine and warmth is more than just a weather forecast, it is a promise of good things and normality and fun and enjoyment. When someone promises you that, and it doesn't happen, you tend to take it personally, and that is when it hurts!
As an update to the above blog, please note that today dawned sunny and with clear blue skies as far as the eye can see. The eurphoria generated by this is remarkable, not just in our household, but in the village as a whole. Long may it last, but the forecast for Monday is cold and wet again...
Posted by: Jane Holland | 07/13/2007 at 09:53 AM