"Unprecedented" rainfall that has forced the evacuation of almost 600 homes in Lincolnshire is set to continue.
Up to 20mm of rain is forecast in affected areas in the coming days, on top of the 132mm that fell in just two days last week - the equivalent of two months' worth of rainfall.
Met Office meteorologist Simon Partridge said there was potential for "thundery and heavy rain" on either Tuesday or Wednesday.
He added: "A little bit of uncertainty about when it will arrive but it will be pushing in from the south and will leave from northeast England."
Properties around Wainfleet have been some of the worst affected in the flooding after the River Steeping burst its banks on Wednesday.
It led to a multi-agency response, including RAF helicopters dropping hundreds of sandbags to repair the river bank, and the Environment Agency putting together pumps to redirect the water.
The Environment Agency has since described the flooding as an "unprecedented event".
MP Matt Warman praised the "incredible" emergency response to the flooding, but said residents were "by no means out of the woods yet".
He said: "Local people should keep an eye on the police because there is still the potential for risk to homes and lives".
On Saturday, the Maritime and Coastguard Agency helped with evacuations, including 300 properties in Wainfleet.
Residents from at least 590 homes in the area have so far been advised to leave.
In a statement on Saturday, Lincolnshire Police said: "Our advice still remains and has been extended to around 300 homes (in addition to the 290 already advised and assisted to evacuate)".