The Met Office warning is valid from 9pm tonight until 6pm on Wednesday.
Outbreaks of rain, persistent and heavy at times, are expected to spread east across southern England overnight and into the morning.
The Met Office warning, as at 11am today, says: “Many parts of the warning area have already seen large rainfall accumulations over the past few days and therefore this further rain may cause come minor local surface water flooding. Lightning may be an additional hazard.
“A frontal wave is expected to move in from the south-west later today, bringing some heavy rain to southern England, accumulations of 20-40mm could be possible quite widely within the warning area, whilst 50-60mm is possible in one or two places.
“The public should be aware that some local disruption to transport looks likely.
“Rain is expected to become increasingly confined to the south-east on Wednesday.”
Check the latest warnings at metoffice.co.uk.
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