Heavy and persistent rainfall is forecast to arrive in Cumbria just before midnight, and is due to continue through Wednesday before clearing by mid-afternoon.
Potentially significant rainfall accumulations are possible over high ground, which will be accompanied by strong winds. River and lake levels are expected to rise from early Wednesday morning and through Wednesday daytime as a result of the forecast rainfall, which could result in localised flooding of low lying land and roads.
In anticipation of rising river and lake levels over the coming hours, the Environment Agency will be issuing Flood Alerts for all catchments in Cumbria.
Given the time of year and the strong winds forecast, the risk of blockages on watercourses and drainage systems from falling leaf litter and branches is increased.
Environment Agency operational teams have been clearing blockages on watercourses in preparation throughout today. Environment Agency duty officers are monitoring rainfall, river and lake levels closely.
A spokesman for the Met Office said: “Rain is expected to set in at the end of Tuesday, becoming heavy early on Wednesday, especially over high ground.
“Rain will be clearing southeastwards during the afternoon but before this happens, 50 to 80 mm may fall across hills, with perhaps 100 mm over the Cumbrian fells.”