There is also a new weather warning for snow in effect on Thursday.
The warning reads: “Sleet and snow expected to cause some travel disruption.”
Rain and hill snow will move eastwards late Wednesday evening and during the early hours of Thursday.
Snow is expected over hills and mountains in Wales and also over the Cotswolds and Chilterns.
In southern Wales up to two inches (5cm) of snow is likely, mainly above 200 metres, while up to 1.2 inches (3cm) is likely over the Cotswolds, Chilterns, and parts of the Midlands above 150 metres.
Away from hills, rain may turn to sleet and snow for a time over parts of the Midlands, East Anglia and the Northern Home Counties.
Snow accumulations at these low-levels will be mostly small, especially on roads, but half an inch or so is possible in one or two places.
Rain, sleet and snow will quickly clear southeastwards by late morning and any snow at lower levels will soon thaw.
The Thursday yellow weather will be in force from midnight to 12pm on Thursday.
The warning will predominantly impact the following regions:
- East Midlands
- East of England
- London and South East London
- South West England
- West Midlands.