The Fed is expected to raise interest rates for the first time this year on Wednesday, and markets are hoping for clarity on whether it intends to stick with its current forecast for three rate hikes this year or raise it to four.

In an otherwise quiet week, the Fed is likely to be the driving force for markets, as traders also watch Washington for any further shakeups from the White House or trade developments.

The big debate in the market is whether the Fed keeps its current forecast, or moves it up to four for 2018, as many economists expect. The Fed releases its economic and interest rate forecasts after the meeting, which is the first for Fed Chair Jerome Powell.

Jonathan Golub, Credit Suisse chief U.S. equity strategist, said he believes the stock market still expects three rate hikes.

"I don't think that Powell has any incentive to come out with guns blazing and disappoint the markets right now," he said, adding there's no real pressure on the Fed from inflation. "The last jobs report said the risk [of inflation] was less than we might have thought. I don't think we're going to get a punch in the nose from the Fed this week."

The Fed has said it expects inflation to move toward its 2 percent target by the end of the year. Core consumer price index inflation rose 1.8 percent in February. A pickup in inflation could push the Fed to raise interest rates faster.

"We changed our call from three to four hikes. We think they'll do another 25 basis points hike. They acknowledged the economy is on a fairly robust path without too many signs of overheating," said Boris Rjavinksi, director of rate strategy at Wells Fargo. "Last time around, they upgraded their language on inflation."

A 25-basis-point hike would put the fed funds target rate range at 1.50 to 1.75 percent, and four hikes this year would take it to 2.25 to 2.50 percent. Some economists expect the Fed to hold next year's hikes at two.

Rjavinski said the rates market is already pricing in more than three hikes for 2018. The yield on the also moved ahead of the Fed rate increase, rising to 2.295 percent Friday, its highest level since September 2008. The 2-year is most sensitive to Fed policy.

The Fed could be positive for the dollar, which has been firming ahead of the meeting.

Ben Randol, G-10 currency strategist at Bank of America Merrill Lynch, said it's possible the Fed could increase its rate hike forecast for both years.

"Broadly speaking, the fundamentals are all supporting the dollar higher for the most part. The issue for the dollar is investor sentiment is very negative on it, and some of the perceived political issues in Washington are not helping the dollar," he said.

Markets are watching for the next shoe to drop in Washington, after Secretary of State Rex Tillerson was replaced by CIA Director Mike Pompeo this past week. That follows the exit of White House economic advisor Gary Cohn, the week before. He was replaced by Larry Kudlow, a former senior CNBC contributor.

"I think, in general, the market has to deal with this backdrop of constant political headlines. That's just a latent risk there," said Rjavinski.

Besides the Fed, there are a few economic reports, including existing home sales Wednesday morning and durable goods on Friday.

Earnings in the week ahead include Oracle on Monday, FedEx on Tuesday and Nike on Thursday.