Natural-gas prices closed higher Thursday, rebounding in the afternoon despite a stockpile update that showed a larger surplus than expected. The front-month September contract settled up 6.6 cents, or 1.7%, to $3.889 a million British thermal units on the New York Mercantile Exchange. Prices fell 1.9% immediately after the weekly stockpile update at 10:30 a.m., but then steadily rose through the afternoon to close at their highest point in a week. Traders and analysts had trouble explaining the turn. It could have been because of heat that is peaking in the Midwest and South this week, Jim Ritterbusch, president of energy-advisory firm Ritterbusch & Associates, said in a note. But the most recent updates had pointed to cooler weather, suggesting that there would not be a lingering demand spike for gas-fueled power to run air conditioners. “It’s very hard to figure out […]