The Met Office says there is potential for thunder and showers in Canterbury today.
Rain could start falling around 10am and may last all day with thundery downpours kicking in around 8pm.
Not everywhere in south-east England will see the downpours, but the Met Office has issued a yellow weather warning for the region.
It says warm air pushing up from the continent will bring a slow-moving band of thunderstorms to parts of central and southern England.
Chief Meteorologist Andy Page said: “The worst impacts are likely during the afternoon and evening on Thursday with the potential for 30-40mm of rain to fall in an hour, and a chance of some isolated places seeing as much as 60-80mm over two to three hours.
“Some will see frequent lightning and large hail as well. This could result in flash flooding, transport delays and dangerous driving conditions.
“We’d advise anyone with outdoor plans over the next few days to keep updated with the forecast and warnings, and consider their plans if the risk of thunderstorms or heavy rain may affect them”.
The rain played havoc with transport in Kent on Tuesday.
Water flooded railway lines tracks while the M2 between Faversham and Sittingbourne became a river.
Friday is forecast to see yet more thunderstorms and showers.
Kate Marks, the Environment Agency flood duty manager, said: “Further heavy showers and scattered thunderstorms bring a risk of localised surface water and river flooding on Thursday and Friday.
“Throughout this period of unsettled stormy weather we will continue to work around the clock operating flood defences, clearing blockages in rivers and streams to ensure they flow freely, and supporting partners responding to any incidents of surface water flooding.
“We remind people not to drive through flood water as just 30cm can move your car.”