NEW YORK ( TheStreet) -- In keeping with the "not if but when" shift in sentiment of late about additional monetary stimulus, the predictions about what QE3 may entail are starting to roll in. Bank of America Merrill Lynch, for one, is expecting the Federal Reserve to go pretty big at its Sept. 12-13 meeting. Here's the firm's characterization of the central bank's thought process: "In our view, the Fed will move when it is comfortable that the growth slowdown is likely to persist." With the data still pointing in that direction -- Thursday's drop in weekly initial jobless claims aside -- B of A revised its expectations of QE3's parameters to reflect a more aggressive move than previously predicted. "We now believe that the Fed will extend its forward guidance to "at least through late-2015" on August 1, rather than through 'mid-2015.' We also expect the announcement of a $600bn QE program in Treasuries and MBS mortgage-backed securities on September 13, up from $500bn in our old forecast," the firm said. "We expect lower 5-10y rates in the near term and recommend fading any significant knee jerk back-up in rates on a QE3 announcement. We believe that QE3 will be much less effective than QE1/ QE2, both in terms of boosting risky assets and stimulating the economy." B of A also offered up some color on the Fed's "nuclear options," which are measures it says "will be much harder to implement, but would likely be much more effective." "These include imposing a ceiling on yields; open ended asset purchases until certain mandate triggers are met (mandate targeting); FX intervention to weaken the dollar; money financed fiscal expansion and raising the inflation target above 2%," the firm said. "In our view, the nuclear options become likely if the Fed believes the economy is sliding into recession or sees high risk of deflation." Meantime, Scott Wren, senior equity strategist at Wells Fargo, backed the firm's year-end target range for the S&P 500 of 1400-1450 late Wednesday and offered up some advice on how to play the volatility that's likely to crop up in August when many of Wall Street's heavy hitters are on vacation and Europe basically shuts down. "We would not advise investors to chase the market on any rally toward the highs seen in earlier in the year but those investors with a 9+ month outlook can continue to build positions in quality companies," he said. Wren added later: "So while many investors will be spending the month of August at the beach, the financial markets will not necessarily wait for vacations to end and the kids to be back in school to before making a material move. We look for volatility to increase as we move into the fall and buying opportunities to be created. Do not get too complacent, the summer doldrums could suddenly come to an end when most market participants least expect it." It will interesting to see if this Mario Draghi-inspired rally has any legs. At least some of the euphoric reaction to the European Central Bank president's vague pledge to do "whatever it takes" to keep the eurozone in one piece has to be attributed to the preceding weakness.