Blackrock’s Bob Doll says he sees more upside for stocks, but thinks volatility will be high for the rest of the year.

“We still believe there is further upside potential for stocks and other risk assets, but given all of the uncertainty, we expect the rest of the year will see some heightened levels of volatility as investors remain quite nervous about the number of downside risks,” Doll writes in his weekly commentary on Blackrock’s site. “There is little room for policy errors, but the trends to seem to be heading in the right direction.”

Doll says he thinks “the continuation of the current up-leg in global risk assets will largely be determined by the aggressiveness and success of policymakers in three critical regions: China, Europe and the United States.” He says the European Central Bank’s bond-buying problem won’t solve Europe’s troubles by itself, but “will offer a financial bridge to allow for structural and political changes to be made.” In the U.S., he says risks are growing surrounding the “fiscal cliff”. He expects the U.S. to continue to grow at about a 2% rate for some time.