Ocean-effect Snow on Cape Cod Overnight Tuesday Night – a Few Inches Possible

Wind from the northwest carrying very cold air over relatively warm ocean water has brought favorable conditions for ocean-effect snow to develop on Cape Cod.  The most impressive ocean-effect events typically come with cold air and an onshore wind - that's not the case this time.  In this instance, however, the air is cold enough, and the wind will be just the right speed (not too fast) to allow cold air parcels sufficient residence time over warm water - allowing for development of convective clouds that will produce snow showers and squalls.  Though a dusting is possible as far west as the mid-Cape, focus will be on the Outer Cape from Provincetown south to Chatham, with Wellfleet and Truro susceptible to amounts locally exceeding 3" given an expected 20 to 1 snow to water ratio.  Southeast of Lake Champlain, Vermont, some lake-effect flurries are also possible tonight, with a dusting of snow southeast of the lake and into the Northern Green Mountains.