Whilst some places may remain mostly dry, areas of heavy rain and some thunderstorms are expected to develop from around mid-morning. In the south of this warning area, the focus is likely to be slow-moving heavy showers and thunderstorms, perhaps with hail and lightning, which should gradually ease away later on Tuesday evening. Meanwhile, further north in the warning area, early showers are likely to merge into more general rain, this heavy and thundery at times, and will persist onwards into Wednesday (which is covered by a separate warning). Across the warning area, 20-30mm in 1 hour or less is possible (but perhaps most likely to the south of London), with a few places perhaps receiving 40-50mm in 2-3 hours. What should I do? Consider if your location is at risk of flash flooding. If so, consider preparing a flood plan and an emergency flood kit. Prepare to protect your property and people from injury. Before gusty winds arrive, check to ensure moveable objects or temporary structures are well secured. Items include; bins, garden furniture, trampolines, tents, gazebos, sheds, and fences. Give yourself the best chance of avoiding delays by checking road conditions if driving, or bus and train timetables, amending your travel plans if necessary. People cope better with power cuts when they have prepared for them in advance. It’s easy to do; consider gathering torches and batteries, a mobile phone power pack and other essential items. If you find yourself outside and hear thunder, protect yourself by finding a safe enclosed shelter (such as a car). Do not shelter under or near trees, or other structures which may be struck by lightning. If you are on an elevated area move to lower ground. Be prepared for weather warnings to change quickly: when a weather warning is issued, the Met Office recommends staying up to date with the weather forecast in your area. For further details see https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings