Rain is likely to begin falling late tonight across southwestern Connecticut, the National Weather Service warns, with flooding a threat after heavier downpours tomorrow and Friday.

Skies over the region will be sunny in the morning, but clouds move in later as the high temperature climbs to about 40 degrees.

Rainfall is expected to begin overnight as the temperature falls to the freezing mark. There will be an east wind between 14 and 17 mph.

The rain will continue falling tomorrow, prompting the NWS to issue a flood watch for the region through Friday morning. Tomorrow's daytime high should be in the mid-40s, and a wind from the east will register between 15 and 17 mph.

Precipitation is expected to get heavier tomorrow night, with rainfall amounts as high as 2 to 4 inches, according to the NWS. Runoff from that rain, combined with snowmelt and already-saturated ground, could trigger new flooding. There also will be breezy conditions overnight, with an east wind between 17 and 20 mph.

On Friday, the rain is expected to continue falling before 1 p.m. The daytime high will be in the mid-50s, the NWS says. There is a slight chance of showers before midnight.

Saturday promises to be mostly sunny, the weather service predicts, with a high near 50 degrees.