Wall Street economists are raising their expectations for more quantitative easing, or QE3, while lowering growth forecasts, and some believe the Federal Reserve may not be able to wait even until its annual conference at Jackson Hole later this month before announcing the next round of easing measures, a Reuters poll has found.

Nineteen out of the 20 primary dealers, the securities firms authorized to deal directly with the Fed to help implement monetary policy, responded to a poll conducted after the Federal Open Market Committee meeting on Tuesday.

Their median forecast for annualized year over year GDP growth fell to 1.7 percent from 1.8 percent in a reading by Reuters taken on Friday, after the Labor Department announced that U.S. nonfarm payrolls rose by a bigger-than-expected 117,000 jobs in July.

The median percent chance the dealers gave of a third round of quantitative easing by the Fed within the next six months rose from 27.5 percent on Friday to 37.5 percent on Tuesday.

The median percent chance that the U.S. would slip back into a recession within the next year rose to 30 percent from 15 percent on Nov 5, the last time Reuters asked primary dealers the question.

Two economists thought the Fed would have a harder time implementing QE3 since the latest FOMC decision came with dissent from three members of the committee. Two others said the Fed might be forced to announce QE3 even before the Aug 26 Jackson Hole conference, if financial market conditions deteriorated enough.