In June members of the rate-setting panel predicted that the main rate would end 2020 at 2.1 per cent, foreshadowing the rate cut announced in July but pencilling in no further reductions over that period.
The market's divergence from the Fed's stated intentions leaves Powell in an uncomfortable position ahead of the central bank's annual economic symposium in Jackson Hole, Wyoming next week. Treasuries have added US$1 trillion ($1.5t) in market value in the past eight months alone: Any snapback could shake markets and tighten financial conditions just as the global economy is showing signs of strain.
The situation today echoes the spring and summer of 2013, when Powell was one of the "three amigos" who had become uneasy with the Fed's vast bond purchasing programme given the extent of the recovery from the 2008-09 recession.
Powell, then a new governor, implored fellow policymakers to set the stage for a reduction in bond buying to show markets that the central bank was serious in its pledge to react to incoming data.
"We've got to jump," he told his colleagues during the June 2013 meeting, referring to making a formal announcement on tapering the bond purchases.
Later that day, Bernanke told a press conference the Fed planned to "moderate" its bond buying, building on Congressional testimony he made the previous month that had already begun rattling Wall Street.
The market reaction was swift and fierce. US government debt sold off, equities dropped and the dollar soared. Ructions in financial markets rippled to Main Street, raising the 30-year mortgage rate by half a percentage point in a week.
Speaking earlier this year alongside his predecessors, Janet Yellen and Ben Bernanke, Powell admitted that the taper tantrum "left scars" on everyone working at the Fed at that time.
"The possible economic consequences were troubling," Bernanke reflected in a memoir.
Recent market gyrations suggest the cost of miscommunication could be even greater this time round.
Written by: Adam Samson
© Financial Times