Powell twinned his remarks, whose hawkish tone took some analysts by surprise, with an observation that the economic risk from an emergent variant of COVID-19 will be better understood by the Fed's Dec. 14-15 policy meeting but will in any case be far less than in the spring of 2020 when the pandemic erupted.
"Since the last meeting, we've seen basically elevated inflation pressures, we've seen very strong labor market data without any improvement in labor supply, we've seen strong spending data too," the Fed chief told members of the Senate Banking Committee.
High inflation, now running at more than twice the Fed's flexible target of 2% annually but which the central bank has for months characterized as "transitory," is only expected to ease in the second half of 2022, Powell said.
Given how long it has lasted, Powell said: "I think it's probably a good time to retire that word."
Earlier this month, the Fed began reducing its purchases of Treasuries and mortgage-backed securities from $120 billion per month at a pace that would put it on track to complete the wind-down by mid-2022. The program was introduced in early 2020 to help nurse the economy through the COVID-19 pandemic.
In his testimony, Powell said "we are actually at our next meeting in a couple of weeks going to have a discussion about accelerating that taper by a few months."
His comments follow those of a number of Fed officials who in recent weeks have advocated for, or at least signaled an openness to, ending asset purchases sometime in the spring to allow for an earlier start of interest rate increases should they be needed to rein in inflation.
In recent days, the emergence of the Omicron variant has unnerved global financial markets, amid fears that it could spread faster, pierce vaccination protections, and be more severe than the current dominant Delta strain.
Powell's remarks helped drive U.S. stocks lower, with the S&P 500 index shedding 1.3%, and cooled a rally in U.S. Treasuries.
Interest-rate futures traders returned to pricing in a June start to Fed interest rate hikes and at least one more increase in borrowing costs before the end of 2022
"It now looks like it will take a deterioration in the public health situation over the next two weeks to prevent the FOMC (Federal Open Market Committee) from deciding to quicken the pace of tapering at the next meeting," Michael Feroli, an economist at JP Morgan, wrote in a note.
Health officials are racing to determine how transmissible and deadly the new Omicron variant is and to what extent current vaccines remain protective. The United States has imposed a travel ban on some southern African nations where the strain is prevalent.
The Delta variant dented the U.S. economy over the summer, slowing employment gains amid workers' fears of contracting the virus and exacerbating supply chain snags that have driven up inflation.
"It's really about transmissibility, it's about the ability of the vaccines to address any new variant, it's about the severity of the disease once it's contracted ... I am told by experts we'll know quite a bit about those answers within about a month," Powell said in his testimony. "We'll know something, though, within a week to 10 days."
"Then and only then can we make an assessment of what the impact would be on the economy ... For now, it's a risk to the baseline, it's not really baked into our forecast."
Nonetheless, Powell acknowledged that Omicron is elevating the uncertainty around the outlook for the economy - and potentially adding to inflation risks - though he said he does not think its effects will be "remotely comparable" to March 2020 when the pandemic cast the economy into a short but historically deep recession.
Powell is scheduled to testify on Wednesday before the U.S. House of Representatives Financial Services Committee.
(Additional reporting by Jonnelle Marte in New York and Karen Pierog in Chicago; Writing by Dan Burns; Editing by Richard Pullin and Paul Simao)
By Lindsay Dunsmuir and Ann Saphir