Oil has surged 20 percent this month to $57 a barrel as expanding violence in Yemen stoked concern that supplies could be disrupted. The rally follows the biggest drop since 2008, with crude falling as low as $43.46 a barrel in March, as a price war broke out between OPEC producers and U.S. shale drillers. West Texas Intermediate oil, the U.S. benchmark, is now back up at close to a four-month high. Prices gained in each of the last six weeks, the longest stretch in more than a year. Before deciding prices will race back to $100, here are five charts worth keeping in mind. “The cart is moving ahead of the horse,” Barclays Plc analysts said in an April 27 report. Long-dated futures are falling Even as prices rise for oil contracts that will be settled in the next few months, the price of oil is actually falling […]