Specifically, these regions could an area of rain move from west to east across the south of the UK and prove to be especially persistent over mid and south Wales, areas which have already been inundated with heavy snow and are waterlogged.
Rainfall of 0.8 to 1.6 inches (20 to 40mm) is likely fairly widely and a few spots in the mountains of South Wales could see two to 2.4 inches (50 to 60mm).
Three more weather warnings for snow, wind and rain are in effect on Monday.
Met Office chief forecaster Dan Suri said: “A relatively deep area of low-pressure system on Monday provides a continuation of the extremely unsettled period the UK has endured.
“Despite reports to the contrary, this system hasn’t been named, and there is no plan to do so currently, despite some speculation on social media.
“With further rain in the forecast over the coming days, additional rainfall could create further challenges as river catchments are more likely to respond to extra rainfall more quickly.
“Flooding, especially in areas already heavily affected, remains a possibility.”