The Federal Reserve had expected to begin withdrawing its support for the nation’s economic recovery this year, but mounting evidence of a global slowdown could extend the era of easy money. Fed officials have signaled for months that they are getting closer to raising the central bank’s target interest rate and many investors had anticipated the milestone would come at the next Fed meeting in mid-September. But that timeline now appears less likely according to a growing list of prominent economists including Larry Summers and New York Fed President William Dudley. The ending of the Fed’s stimulus has the potential to roil financial markets already bruised by the slowdown in China.