How the Fed could challenge markets
How the Fed could challenge markets · CNBC

Markets are ready for the Fed to bring on a quarter-point rate hike after seven years at zero, but it's the nuances in its statement and forecasts that could be more challenging.

"The consensus view around the world seems to be it will be a dovish hike, and it will be, relative to history, but it may not be relative to what are now very high expectations that it will be dovish," said Tony Crescenzi, senior vice president and Pimco portfolio manager.

The Fed is expected to raise the fed funds target rate Wednesday and release economic and interest rate forecasts with its 2 p.m. ET statement. Fed Chair Janet Yellen then briefs the media at 2:30 p.m.


Read More Interest rate hike coming? What you need to know

One key will be in the Fed's forecasts for interest rates, which are displayed in a chart known as the "dot plot."

"It may not have the dovish hike feel to it that some want, mainly because the summary of economic projections and the dot plot will seem to indicate there's a reasonable chance for more (hikes)," said Crescenzi. "The dots are positioned for three to four, and the market is positioned for two to three. It may seem out of sync with the dovish hike view."

George Goncalves, head of U.S. rate strategy at Nomura, said the bond market will certainly react to the rate forecast. If Fed officials lower their forecast to just two rate hikes, that would be bullish for bonds, and three would be slightly less bullish. "If they stay, the bond market would sell off," he said.

Read More There are more "junior varsity" Fed watchers than ever before

"I think they'll try to convey the message that this is the beginning of a process that's going to take a long time and is very slow. they don't want the market to freak-out that this is going to be a Greenspanian 25 basis points every-six-weeks hike. I think we'll only get two hikes next year," said Jefferies chief financial economist Ward McCarthy. He was referring to the rate hike policy under former Fed Chairman Alan Greenspan.

"The message used for tomorrow's action is "dovish tightening," which is an oxymoron. I think the Fed will do what they have to do and try to take as much sting out of it as possible," he said.

McCarthy said there's plenty of opportunities for the markets to mistake the Fed's message. "There's just too much information they're trying to convey. I think there will be confusion and consequential volatility, but when the dust settles I think bonds will be little changed and I think stocks will be higher," he said. As for the dollar, "I think that's a pretty crowded trade. It wouldn't surprise me if the dollar is lower initially. But I do think as time passes, there's still upside."