When cold air sits over land, an approaching weather system, with warm air, can enhance the temperature contrast across the shoreline. Sometimes, this “coastal front” enhances precipitation, especially snow, as moist air from the sea moves across the coast to the colder inland.
It is this process that may induce some locally heavier snowfalls along the Atlantic or Fundy coast on Wednesday, before the snow changes briefly to rain.
I’ll update this scenario in the morning via twitter…