A wet weekend is in store for southwestern Connecticut, according to the National Weather Service, which warns Sunday could be the flashpoint for potentially heavy rain and flooding.

Today should be partly sunny, with a high temperature near 37 degrees. There will be a southeast wind between 5 and 14 mph.

Overnight, the NWS says, there is a slight chance of snow and sleet between midnight and 3 a.m., then changing to all rain. It will be relatively warm, though with a low of about 34 degrees and a south wind between 8 and 11 mph.

Tomorrow there is a chance of light rain, mainly after noon. Skies will be cloudy, with a high near 50 degrees. The possibility of rain increases to 40 percent by nighttime, when the low is expected to 42 degrees. There also could be some patchy fog.

Saturday night is the period when the NWS hazardous weather outlook -- through Monday morning -- warns that periods of heavy rain are possible.

The rain should start falling Sunday morning, probably after 9 a.m., causing fog as the daytime high temperature climbs into the low-50s. Rain remains in the forecast through Sunday night, which is likely to have a low temperature in the mid-30s.

And more rain is possible Monday morning, which also expected to be cloudy and breezy.