The Fed's move Wednesday afternoon is coming against a backdrop of financial market turbulence. Markets have been reacting to concerns about rising interest rates as well as concerns that trade wars and weaker global data could lead to a recession. Fed Chairman Jerome Powell, unlike other Fed chairs, has also faced a stream of criticism from the White House, with President Donald Trump protesting rate hikes and in a tweet on Tuesday, the Fed's balance-sheet policy.

The Fed releases its statement and projections at 2 p.m. ET, and Powell will speak at 2:30 p.m. Stock futures pointed to higher openings Wednesday morning.

"The economy is decelerating. They were too optimistic on their outlook, but by the same token, they're going to have to walk a fine line that they're not overly concerned," said George Goncalves, head of fixed income strategy at Nomura. "They're just going to take it down a notch."

The Fed is seen as likely to take the fed funds rate range to 2.25 to 2.50 percent and to remove language in its post-meeting statement that says it will continue with "gradual" rate increases. The Fed has said it expected to raise interest rates three more times next year, but economists now think that will change to show two more hikes next year, with another possible in 2020.

Strategists say that may soothe volatile financial markets , but the Fed has a tough task in explaining its actions in a way that will not sound too alarmist about the economy or too unconcerned about deteriorating financial conditions.

The Federal Reserve is expected to raise interest rates by a quarter point Wednesday and signal it will not be pushing rates higher as much as it had previously forecast.

"I do think the Fed will try and likely succeed in sending a comforting tone to the equity market," said Mark Cabana, head of U.S. short rate strategy at Bank of America Merrill Lynch. "I think the market is forcing the Fed to deliver a very dovish hike. We think 2019 dots will come to two. 2020 will show one hike but just above 3 percent. The Fed will make some changes to show they are less on a preset course and more data dependent."

As for Trump, strategists expect Powell to sidestep criticism from the president while signaling the Fed remains independent. Trump is not alone in his concern that Fed will make a misstep and its rate hikes will slow the economy, but the market is widely expecting a rate hike Wednesday.

"I think the criticism from the president is pretty much counter-productive. The Fed very much prizes its independence," said Cabana. "I feel if Trump really pushes the Fed, they are going to want to assert the independence they have. ... If it was truly a 50/50 rate hike call, they would probably err on the side of raising rates just to re-establish their independence."

The Fed is also expected to lower its growth forecast and possibly its inflation forecast to under 2 percent. The Fed raised its 2019 growth rate to 2.5 percent in September but could bring it back down to 2.3 or so, Fed watchers said.

Diane Swonk, chief economist at Grant Thornton, said Powell is a Fed chairman much more freely willing to admit it's difficult to tell where the economy is going, and is therefore "much more willing to be flexible." He does take into account tightening financial conditions as well, she added.

Swonk said the economy is going from "strong to solid." "'That's important that the economy is slowing, but it's not slow enough for them to be panicky. It's going to be a terrific holiday season," said Swonk.

Besides the fed funds target rate, the Fed will likely raise the rate on interest on excess reserves by 20 basis points. It's a technical move to keep the fed funds rate within its target range.

"The Fed no doubt hears the criticism but they're going to be guided by the data. Clearly, the financial markets are sending a signal that the Fed hears loud and clear, but they also don't want to be swung around by financial markets," he said. "They're going to weigh the hard economic data and if the data says pause, the Fed will pause."