Heavy showers and thunderstorms have been forecast to hit Kent later today, as the Met Office issues a severe weather warning.
Downpours are likely to continue through Saturday and into the evening throughout the south east, London and the east of England.
But scientists predict the main risk will become confined to southern parts of the country from late on Saturday afternoon.
The Met Office is warning people to be aware that roads and surfaces may flood and that lightning strikes may cause disruption.
The warning comes a day after hundreds of commuters struggled to reach the capital yesterday after a lightning strike in Otford damaged signalling equipment.
Services between Ashford International and London Victoria via Maidstone East were being cancelled, delayed or diverted.