Aug 19 (Reuters) - Federal Reserve Chair Jerome Powell will speak on "the economic outlook" at next week"s Jackson Hole, Wyoming symposium, the central bank said on Thursday. The generic description for the highly anticipated speech contrasts with last year"s more specific listed subject for the address, "Monetary Policy Framework Review", and gives investors and analysts no immediate clues on the Fed"s timeline for withdrawing its support for the economy. Minutes of the Fed"s July meeting suggest policymakers are coalescing around beginning to taper their $120 billion in monthly asset purchases before the end of the year. Some analysts expect Powell to lay out a clearer roadmap next week, particularly if he wants to keep the door open to an earlier start to tapering as favored by some Fed policymakers worried by recent high readings on inflation. Powell himself has argued that those readings are likely temporary. Reporting by Ann Saphir Editing by Chris Reese and Sam Holmes Our Standards: The Thomson Reuters Trust Principles.