A powerful arctic blast swept into the U.S. Northeast on Friday, threatening to push temperatures to record lows in many spots, including New Hampshire’s Mount Washington, where the wind chill could drop to -110 degrees Fahrenheit ... ... Boston and Worcester, the two largest cities in New England, were among the school districts to close on Friday as administrators worried about the risk of hypothermia and frostbite as children waited for buses or walked to school. The bitter cold in the forecast forced a rare closing of a floating museum that presents a daily re-enactment of the 1773 Boston Tea...