U.S. stock futures advanced on Wednesday, as Wall Street got ready to reopen after Hurricane Sandy forced its two day closure. General Motors Co.'s higher-than-expected earnings and Chicago PMI due today in focus. Futures on the Dow Jones added 0.4% to 13,106, while those on the S&P 500 surged 0.5% to 1,415.20. Nasdaq 100 futures rose 0.5% to 2,667.25.