Checking the Forecast

We all look at weather forecasts, some more than others. In years gone by, forecasts had a reputation for being unreliable. While there have been a few famous clangers that people still drag out whenever they want to have a moan, nowadays it's felt that generally they aren't too bad. Although how much our perceptions are affected by the whizziness of the computer graphics (compared to the hand-drawn charts used in the days of Black&White TV) compared to the actual content of the forecast, is a question for another time.

However, we do tend to take them for granted. Glance at the 'paper or the screen. Get a superficial impression of what we think the presenter might have said and forget all the detail before we've got as far as the front door. As for the longer term (compared to morning forecasts for the coming day), when was the last time you could remember what the forecast was for 2 or 3 days hence? I know I have no idea. Now, there are obviously people in the country for whom an accurate forecast is important. Farmers, hikers, the fishing industry, pilots all need to be alerted of up-coming dangers and can buy specialised forecasts for their small areas that are far more detailed than the ones we instantly forget over breakfast.

But how good are the general-purpose forecasts we get? Since I took up astronomy, I have become a lot more aware of weather. While on a daily basis I, like most people, am fairly well insulated from the weather (centrally-heated house, to car, to office or supermarket - and then back) I was initially surprised at just how few clear nights we have in Britian. That led on to paying more attention to the forecast, and in turn looking further ahead than just the forecast for "today" - which is really only a forecast for the up-coming period of daylight, most people are virtually unaware of weather at night unless it's stormy or swelteringly hot.

Over the past year I have dutifully been taking note of the 5-day forecast that apears on the BBC website and recording each days information. The following few pages are about what I have found and the conclusions that I've drawn from analysing a year's worth of weather reports.