Stock exchange traded funds opened higher Wednesday following blowout earnings from tech giant Apple (NasdaqGS: AAPL), but the afternoon Federal Reserve announcement should set the pace for the rest of the session.

The central bank will release its statement on interest rates in the economy in the afternoon following the two-day meeting. Fed chief Ben Bernanke will also hold a press conference.

The tech sector was outperforming Wednesday after Apple reported total revenue growth of 59%, more than 80% growth in iPhone shipments and 150% year-over-year growth in iPad shipments. [QQQ Leads Dow, S&P on Apple Earnings]

Apple shares recovered some of their recent losses on the strong quarterly earnings report, but stock ETFs could be volatile Wednesday as investors react to the Fed.

“With both unemployment and inflation in a holding pattern, the Federal Reserve is on hold too,” said David Kelly, chief market strategist at JP Morgan Funds.

“The U.S. economy has clearly shown some positive signs, the most recent jobs data have been a little disappointing while the problems of the Eurozone’s weakest members appear to have worsened,” he added in a weekly outlook. “Overall, while these mixed signals give the Fed little reason to contemplate further quantitative easing, they also are unlikely to change many minds on the timing of eventual tightening.”

The Fed has pledged to keep short-term rates near zero until late 2014.

Full disclosure: Tom Lydon’s clients own AAPL.