Add coastal flooding to the potential weather woes that could buffet southwestern Connecticut today and tomorrow, the National Weather Service warns.

The NWS has issued a flood watch for the region from 10 a.m. today through tomorrow afternoon, warning that rivers and streams already swollen -- in some cases, over their banks -- from the heavy rain and snowmelt earlier this week could flood again from rain expected to start late this morning.

The rain is expected to become heavy tonight, with potential precipitation amounts as high as 2 to 4 inches until it ends midday tomorrow.

Coastal flooding now is also a possibility, the NWS says in a new advisory, primarily during overnight high tides across the region, from about 2 to 4 a.m. tomorrow.

Rain is expected to start falling this morning, with the day's high temperature expected to reach about 45 degrees and an east wind between 17 and 21 mph.

Tonight should see heavier rain -- and occasional downpours -- as the low temperature falls to about 40.

The rain keeps falling tomorrow, the NWS predicts, until early afternoon. The daytime high will be in the mid-50s, with a south wind between 10 and 15 mph. Tomorrow night will be cloudy, with a low around 35.

On Saturday, there is a slight chance of showers after noon. But the day is expected to be partly sunny, with a high near 49 degrees and breezy, with a west wind between 16 and 20 mph.