Temperatures across New England dipped below zero Tuesday, but on Mount Washington in New Hampshire, a different, more anecdotal metric described the treacherous weather: the air was cold enough to freeze a dish of spaghetti, fork included, in mid-air. Like a futuristic sculpture memorializing morning-after leftovers, the plate of pasta stood suspended in its place, its fork defying gravity as it hovered several inches off the snowy ground.