The Met Office Chief Forecaster said: “Heavy showers are expected to break out this afternoon and persist into the evening.
“Due to light winds, some of these showers are likely to be slow-moving, leading to some localised prolonged, torrential thundery downpours which could give 20-25mm of rain in a relatively short space of time and close to 40mm in two or three hours.
“The heaviest showers are most likely during the mid to late afternoon and early evening, so are likely to coincide with the rush hour.
“As is often the case in this sort of situation, some places will miss the showers whilst nearby locations experience heavy downpours and the exact location of where the heaviest showers occur is very uncertain.”
The overall message is - be aware of the potential for localised flooding and disruption to travel.
The yellow ‘be aware’ warning is in place from noon today until 11pm tonight.
A forecast for the rest of the week is that Sussex is due to see some light showers mixed with sunny spells.
However, the temperature is expected to rise above 20degC into the weekend with far more sunshine.
Don’t miss out on all the latest breaking news where you live.
Here are four ways you can be sure you’ll be amongst the first to know what’s going on.
1) Make our website your homepage
2) Like our Facebook page
3) Follow us on Twitter
4) Register with us by clicking on ‘sign in’ (top right corner). You can then receive our daily newsletter AND add your point of view to stories that you read here.
And do share with your family and friends - so they don’t miss out!
Always the first with your local news.
Be part of it.