The Brief While it remains unlikely, there is a possibility of coastal locations across the Bay Area seeing snow flurries this weekend. Gulf-effect snow occurs when much colder air moves over the relatively warm waters of the Gulf. While it remains unlikely, a rare setup known as Gulf-effect snow could give a few coastal locations a slim chance at seeing flurries. What we know:Gulf-effect snow occurs when much colder air moves over the relatively warm waters of the Gulf. That temperature contrast allows warm, moist air to rise and, under just the right conditions, produce narrow bands of snow.