The Met Office has included Londonderry in a list of places in Northern Ireland expected to be hit with heavy rain on Wednesday.
The warning was issued late on Tuesday evening and is valid from 6am and 2pm on Wednesday.
"Many places within the warning area will see 15-20 mm of rain, with around 25 mm in places. As this will fall within a 6 hour period, it is likely to lead to surface water flooding," said the Met Office's Chief Forecaster.
The temperature in Londonderry is also expected to drop considerably as we move towards the end of the week. To keep up-to-date with weather warnings visit the Met Office website.