Natural gas prices surged to their highest closing price in nearly a month as severely cold weather boosts demand. The front-month March contract settled up 11.7 cents, or 4.1%, at $2.951 a million British thermal units on the New York Mercantile Exchange. It was the seventh gain in nine sessions and the highest closing price since Jan. 23. Half of U.S. homes use natural gas for heating fuel and severe cold could be about to drive up their demand for weeks. The U.S. government weather model shifted, creating more agreement between computer weather models about the chance for extended, widespread cold, wrote Aaron Calder, senior market analyst at energy-consulting firm Gelber & Associates in Houston, in a note. “The morning forecasts effectively erased the argument for a March warm-up and forced bearish traders to price in the potential for a long-term cold snap,” Mr. Calder said. […]