Gasoline prices surged Monday on concerns over a shortage in supply after Tropical Storm Harvey knocked out refining operations and traders tried to assess damage in the Houston area. Harvey barreled into Texas on Friday as a Category 4 hurricane , the strongest to hit Texas in half a century, but has since been downgraded to a tropical storm. Still, on Monday it looked poised to move back over the Gulf of Mexico before coming back ashore, dumping more heavy rain on Houston and the surrounding area. Traders remained focused on the possibility that Harvey may now approach Louisiana and that the onslaught could cause damage to fuel-making plants that could take weeks or even months to fix. The storm had disrupted nearly 15% of U.S. refinery capacity as of Monday morning, and the number is climbing. Exxon Mobil Corp. said its 362,300-barrel-a-day refinery in Beaumont, Texas, is running […]