The Met Office has issued a yellow weather warning for heavy rain for Tuesday.
It will be in effect from 6am until 9pm.
Srengthening south to southeast winds will bring with them prolonged periods of often heavy rain with totals of 20 to 30mm widely, but up to about 50mm over the hills.
Given the already saturated ground, there will be a quick runoff of the rain to give areas of surface water flooding, especially in locations where drainage is already poor or blocked, or becomes blocked with autumn debris.
River levels will also rise quite quickly.
The situation will continue to be monitored and further updates will be issued as and when required.