Gov. Phil Murphy and his family are set to leave the country for a Christmas vacation to Costa Rica for the third time in four years. The Murphys are scheduled to head to the Central American nation for the next week or so, his office told NJ Advance Media. They plan to to leave Friday, pending weather. New Jersey has been battered by heavy rain and winds from a powerful winter storm that started Thursday, and temperatures are expected to drop significantly Friday. They are expected to return Jan. 1. Lt. Gov. Sheila Oliver will serve as acting governor while Murphy is away. Because it’s person…