Investors should enjoy the bounce in emerging markets but also beware the coming headwinds, Bessemer Trust Chief Investment Officer Rebecca Patterson said Thursday.

Patterson noted that the reduction of Fed stimulus would eventually end. "So, higher rates are still coming. A stronger dollar is still coming. Those headwinds from emerging markets are still coming. So, from someone who's facing this as a trader, I think you can enjoy this opportunity in EM a little longer, especially selectively," she said.

"For someone allocating, I would just be careful that you don't stay at the party too long."

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On CNBC's "Fast Money," Patterson, who has $60 billion in assets under management, said that EM could still see a bounce but added that it could be running out.

Patterson said that she was underweight EM equities and had reduced EM debt, as well as high-yield U.S. debt, adding that she continued to like developed-market equities.

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The Federal Reserve's decision not to scale back its $85 billion-per-month asset-purchase program, she said, was a "huge policy mistake."

"The market had discounted a modest taper," she said. "It would've been a way of telling the market, 'We're not going to be here forever. The spigot doesn't stay open forever.' I think they blew a great opportunity, frankly. Even if the economy isn't roaring ahead, the fact that housing data, auto data all held up despite higher interest rates this summer made me think that we could probably get through it. So, I think it was a policy mistake."

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But the outlook for stocks was positive, she added.

"I think equities can go higher, especially if we keep seeing confidence data improve," Patterson said. "I think that the share buybacks, the better global backdrop, the fact that it's not Larry Summers taking charge of the Fed after Ben (Bernanke). All that plays into the view, too."

— By CNBC's Bruno J. Navarro. Follow him on Twitter @Bruno_J_Navarro.

— CNBC's Michael Newberg contributed research to this report. Follow him on Twitter: @MikeNewberg.

Trader disclosure: On Sept. 19, 2013, the following stocks and commodities mentioned or intended to be mentioned on CNBC's "Fast Money" were owned by the "Fast Money" traders: Karen Finerman is long BAC; Karen Finerman is long C; Karen Finerman is long JPM; Karen Finerman is long TGT; Karen Finerman is long GOOG; Karen Finerman is long M; Karen Finerman is long JCP; Karen Finerman is long RTY PUTS; Karen Finerman is long MDY PUTS; Karen Finerman is long SPY; Steve Grasso is long BA; Steve Grasso is long BAC; Steve Grasso is long BBRY; Steve Grasso is long GDX; Steve Grasso is long GOOG; Steve Grasso is long HERO; Steve Grasso is long HPQ; Steve Grasso is long MHY; Steve Grasso is long LNG; Steve Grasso is long MJNA; Steve Grasso is long NVIV; Steve Grasso is long PFE; Steve Grasso is long QCOM; Steve Grasso is long S; Steve Grasso is long ASTM; Steve Grasso is long POT; Steve Grasso is long DECK; Steve Grasso is long DHI; Steve Grasso is long EEM; Tim Seymour is long BAC; Tim Seymour is long INTC; Tim Seymour is long SBUX; Tim Seymour is long X; Tim Seymour is long LO; Guy Adami is long C; Guy Adami is long GS; Guy Adami is long INTC; Guy Adami is long MSFT; Guy Adami is long AGU; Guy Adami is long NUE; Guy Adami is long BTU; Guy Adami's wife, Linda Snow, works at Merck.