By Ann Saphir and Howard Schneider

(Reuters) - As recently as two and a half months ago, most U.S. central bankers didn't see an interest rate cut in the cards at their Sept. 17-18 meeting.

By the end of last month, when Federal Reserve Chair Jerome Powell said it was time to start lowering borrowing costs, nearly all of his colleagues thought so too.

In large part, that was because a wide range of data moved in one direction. That pushed Fed policymakers to reassess the risks to their outlook, including whether their chief concern should be persistent inflation, labor market weakness, a deterioration in business or household financial conditions, a potential policy mistake, or some combination of those factors.

"It's not one thing that causes everyone to move. It's different people focus on different data, different indicators, different risks, and then they all end up in the same place," said Kristin Forbes, an economics professor at MIT's Sloan School of Management and a former member of the Bank of England's policy-setting committee.