Due to my passion for surfing, I spend many hours wading through weather charts, tying to calculate the right moment to catch the next great wave.
I don't use the BBC weather sight at all.
What I find when looking at the Met office site is, they generalize all the time. If you want a more accurate forecast for your area or planned activity, it takes a fair bit of effort and time, but it's not difficult. Compare several different sites data. If they all agree that what's coming. If they don't expect changeable weather.
If you planning a Barbi, ie you just want to know the weather for the next few hours, in a single spot. Down load the raw satellite images for the past several hours and simply work out, from what you see, where the clouds and rain are heading for. You can hold a ruler up to the monitor and often work out to within a 10 minutes, or so, when it's going to start or stop raining.
I also use different web sites for collecting different data.
NASA, http://modis.gsfc.nasa.gov/gallery/ and
Met office, http://www.metoffice.gov.uk/public/weather/observations/saltash-cornwall#?tab=map , provide good quality free satellite images. But for wind direction and strength I use.
XCWeather, http://www.xcweather.co.uk/
Any way enough of me waffling hope you find some of it useful.
