The Fed could downgrade its forecasts for economic growth this year and for interest rates in the coming three years, according the survey by The Wall Street Journal. The central bank is scheduled to release its forecasts at its next meeting.

Private analysts surveyed by The Wall Street Journal expect the U.S. economy to expand at 2.1% in 2015, down from the March forecast of 2.9%, driven by the weak first quarter. The growth of 2.1% is below the Fed's March forecast of 2.5%.

Private analysts' forecasts for unemployment and inflation are little changed.

Private analysts expect the Fed to start raising its interest rate in September.