Great sites to visit for all sorts of weather related information.
The Met Office – National Weather data and a whole host of other resources. Check out the Rainfall Radar and the FireFox Met Office Weather Gadget.
Isle Of Wight Weather – Live UK Thunderstorm Tracker, see lightning strikes plotted on a map.
Weather Underground – One of the many sites you can upload personal weather station to. The WunderMap of weather stations is a must. Google Maps driven you can check weather conditions real time anywhere in the world.
POL Hilbre Island – The Proudman Oceanographic Laboratory maintain a remote WX Station, along with a remote webcam on Hilbre Island which is located off the North West tip of the Wirral Pennisula. Data is updated regulary and there are links to many other items of interest such as Tide Tables and Wave Height Radar.