The region's Christmas Eve forecast is for a mostly sunny day, but a "hazardous weather outlook" of heavy snow remains a possibility Sunday afternoon, according to the National Weather Service.

Today's daytime high temperature is likely to be about 37 degrees, with a north wind of about 15 mph. Tonight is expected to be partly cloudy with temperatures falling to a low of about 25.

Christmas Day will be mostly cloudy across southwestern Connecticut, the NWS says, with a high near 34. Clouds continue into nighttime, with a low around 24.

Sunday is when the weather could get nasty, with a 50 percent chance of snow after noon. Skies will be cloudy, with a high near 34, and there will be a north wind between 8 and 14 mph.

The track of this coastal storm -- which could bring "significant snowfall" -- remains uncertain, and the hardest-hit areas may be east of Fairfield County, the weather service says.

The chance of snow continues overnight Sunday into Monday, with cloudy and blustery conditions. The low temperature is predicted to be in the low-20s.