The Commerce Department did its job by publishing a better-than-expected downward revision to economic growth in the second quarter and stock futures are rising. Now, it’s up to Fed Chief Ben Bernanke with today’s other market-moving news, a speech to be delivered at the Fed’s Economic Symposium in Jackson Hole. Reuters offers this preview:

Federal Reserve Chairman Ben Bernanke will have to address a number of pressing issues in a speech on Friday as investors search for more clarity on how close the central bank might be to another asset-buying spree to support the flagging recovery.

Bernanke will also likely touch on fears of waning economic momentum as evidenced by a parade of gloomy indicators, suggesting the U.S. economy has slowed to a crawl when he speaks at the Fed’s annual retreat in the Teton mountains.

He may also note the Fed’s decision earlier this month to renew purchases of assets to replace ones that have rolled off the Fed’s balance sheet.

But he seems unlikely to offer any detailed plan of what the U.S. central bank will do going forward or to define what would trigger more aggressive steps by the Fed.

That could be a problem…