A Federal Reserve interest rate cut in September, the first this year, followed perhaps by another before year-end remains the base forecast for most economists polled by Reuters amid rising concerns about the health of the world's biggest economy.

New economic data releases could increase mortgage rate volatility in the coming weeks, leading up to the Fed's September meeting.

Futures markets are also expecting a rate cut. Investors peg the chances of a quarter-point interest rate cut at nearly 96%, according to the CME FedWatch Tool, a measure of market sentiment.