Mr. Song said that he expected the Fed to hold off on cutting interest rates until September and that he thought Mr. Powell would need to communicate that later timing at his congressional appearances this week.

If there is a case for cutting rates sooner, it hinges on inflation data, he said. Price gains have been mired below the Fed’s 2 percent goal almost permanently since the central bank formally adopted the target back in 2012. That’s a problem because it creates a credibility issue for the Fed and increases the risks that prices could fall into economy-harming price declines in a recession. Deflation would be bad news since it could encourage consumers to hold off on purchases, knowing that they will be cheaper tomorrow, and would exacerbate a downturn.

The Fed’s preferred inflation index increased just 1.5 percent in the year through May, and June figures will be released on July 30, the first day of the Fed’s meeting.

Against that backdrop, and with trade tensions still humming in the background, the Fed may feel justified cutting rates this month even as economic growth data hold up. They set policy with an eye toward the future, since monetary policy moves take time to kick in.

“The question my colleagues and I are grappling with is whether these uncertainties will continue to weigh on the outlook and thus call for additional policy accommodation,” Mr. Powell said in a speech last month.

Moving now could signal the Fed’s commitment to hitting the inflation target and a willingness to proactively offset any fallout as trade tensions drag on.

The case for a rate cut “was never about the labor market, or the consumer, which seemed pretty good,” said Julia Coronado, founder of MacroPolicy Perspectives, who expects a rate cut with the message that the economy “is in a good place, and we’re going to keep it there.”