The Met Office has warned of heavy rain and strong winds for later this week across West Sussex.
A band of heavy rain, with the possibility of some very heavy bursts, will hit West Sussex in the early hours of Friday morning.
In a warning, the Met Office said: "Within this band 10-15 mm of rain is widely expected, however some places could see as much as 30 mm in just a few hours.
"Once the rain has cleared scattered showers and thunderstorms are expected to develop, particularly during Friday. Many places will miss these, but where they do occur 10-20 mm is possible in one hour, with perhaps 30 mm in a few hours."
On Saturday a separate yellow weather warning has been issued for up to 50 mph winds, especially along the coast and up towards Haywards Heath.
Drivers are being warned that spray and flooding could lead to difficult driving conditions and some road closures, with probably some bus and train services affected.