Natural-gas prices rallied Thursday, ending a shortened week with the biggest gain in nearly two years, as traders were buoyed by colder weather forecasts and a larger-than-expected inventory withdrawal in the U.S. Despite the warm temperature on Christmas Eve, prices for the front-month January contract gained 4.6 cents, or 2.3%, to settle at $2.0290 a million British thermal units on the New York Mercantile Exchange. Gas set a new inflation-adjusted low for its history of Nymex trading on Dec. 17, but has gained ground since. For the week, natural gas prices were up 14.8%, the largest one-week percentage gain since the week ended Feb. 21, 2014. The U.S. Energy Information Administration released its weekly update on natural-gas stockpiles, showing that inventories fell by 32 billion cubic feet in the week ended Dec. 18, while analysts and traders surveyed by The Wall Street Journal had expected a decrease of 25 […]