A nasty nor’easter is expected to batter the Cape and Islands this weekend, according to meteorologists who say the bomb cyclone could dump several inches of snow and spark strong wind gusts and coastal flooding. The snow forecast for the Boston-area is around 2 inches, while the South Shore could see close to 6 inches, and the Cape and Islands might get more than 6 inches. Blizzard-like conditions will be possible for Cape Cod, Nantucket and Martha’s Vineyard on Sunday. The National Weather Service’s Boston office has issued a “Winter Storm Watch” for the Cape and Islands from late Saturday night through Sunday night. “Heavy snow possible,” NWS Boston wrote in its alert.