Parts of the UK have been urged to prepare for an “unseasonably cold” and wet start to the week, with weather warnings in place that could mean disruption to the morning rush hour.
Yellow warnings for heavy rain and strong winds are in place for southern and eastern parts of England on Monday.
Some places could see more than a month’s rainfall in one day.
The Environment agency said travel disruption during Monday’s rush hour was expected.
A total of 15 flood alerts – meaning flooding is possible – have been issued across England.
Flooding could result in poor driving conditions and delays to bus and train services, the Met Office added.
There is also a risk of power cuts and flooding to homes and businesses.
The wet and windy weather is the result of an area of low pressure moving northwards overnight on Sunday.
It will feel unseasonably cold for the time of year, the BBC Weather Centre said, with maximum temperatures around 6 to 7C in these areas, but feeling much colder under the rain and wind.
High ground – like the Chilterns and the Cotswolds – could even see sleet and snow, although it won’t settle.
During the course of Monday, affected areas are likely to see rainfall of 25-35mm.
Up to 80mm is possible across parts of Norfolk and the North Downs (average monthly rainfall for Norfolk in April is 44mm).
There will be strong northerly winds too, with gales around eastern coasts with gusts of 40-45mph inland and up to 50-55mph along exposed coasts.
This is a relatively unusual wind direction for the time of year, the Weather Centre added, and trees being in full leaf could cause some problems.
Clare Dinnis, flood duty manager for the Environment Agency, said these winds will lead to “large waves and spray in exposed coastal areas and we encourage people to take care in these locations”.
Ms Dinnis advised people not to drive through floodwater.
Away from these areas, many parts of the UK will have a dry day with some sunshine, although it will feel cold.
It is in sharp contrast to earlier April weather – on 19 April, 29.1C was recorded at St James’s Park in central London, making it the hottest UK day in April since 1949.
The average maximum temperature for the UK in April is 11.9C.