this is from the met office
Issued at: 1020 on Tue 6 Oct 2015 Valid from: 1230 on Tue 6 Oct 2015 Valid to: 2359 on Tue 6 Oct 2015 Although many areas will miss the heaviest rainfall today, some parts of the warning area are likely to see heavy, sometimes thundery and slow-moving showers, these leading to temporary surface water flooding in a few areas, together with minor disruption to travel. A slack area of low pressure will move slowly across southern Britain today, bringing unstable air and the potential for thundery showers. The light winds mean that the downpours will be slow-moving as well as intense in some regions, with the possibility of 15 mm or more falling in less than an hour.
sorry William you don't appear to be included
think the met office is taking a precautionary measure so people don't get caught out and as for thunder that's in very short supply at the moment not that I have a complaint about that