Large swathes of the UK are in for a wet week, with parts of the country already experiencing more than half their average monthly rainfall this October.

The Met Office on Monday issued a yellow weather warning covering central and southern parts of the UK including London.

People in these areas have been warned of heavy rain and a small chance of flooding and disruption.

The warning is in place from noon to midnight with between 0.6in (15mm) and 1in (25mm) of rain expected to fall across the area.

Up to 2.4in (60mm) of rain could fall in isolated areas within the warning area, the Met Office said.

"We have an unsettled week with quite a lot of rain," spokeswoman Nicola Maxey told the PA news agency on Monday.

"There's a warning out for quite a lot of rain to come through today, especially for the southern and central areas, where it will be heaviest."

As of 10.45am, the agency had 44 flood alerts in place across the South West, Midlands and parts of Yorkshire.

Parts of the UK have already seen more than half of their average monthly rainfall, the Met Office said.

The UK as a whole has seen 55 per cent of its average monthly rainfall, which Ms Maxey said is not abnormal for this time of year.

"When you get into winter, you tend to see long spells of rainfall and it comes across the whole month and it's more evenly spread, but we're in that transition period," she said.

The Met Office said Scotland, northern England and the West will remain mostly dry for the first few days of the week before another weather front brings downpours to those areas on Wednesday.

The low pressure system is forecast to start moving across the country on Wednesday night, with a chance of thunder in the West.

Strong winds and locally heavy showers are expected, particularly in the West from Wednesday to Friday.