Getty ImagesFederal Reserve Chair Janet Yellen will try to explain the central bank’s thinking at an hour-long press conference.A sea change is expected in Federal Reserve rate policy this week as the central bank is widely expected to remove the last obstacle to a rate hike later this year. The bulk of the news will come at 2:00 p.m. Eastern on Wednesday. This will include a six-paragraph policy statement, revamped economic forecasts, and the so-called “dot plot” path of interest rates from each of the 17 central bankers.The statement While markets will be keying on a single word —whether the U.S. central bank drops its pledge to be “patient” in raising short-term interest rates — the Fed will send other messages about the strength of the economy and outlook for inflation. In the prior policy statement in January, the Fed said economic activity was advancing at a “solid pace.” The central bankers also said inflation was being pushed lower by transitory factors that would likely dissipate. Another question is whether there will be any dissents. Chicago Fed President Charles Evans is seen as a possible dissenter because he has stated he wants the U.S. central bank to remain on hold until 2015. On the other hand, if the Fed tilts dovish, then Richmond Fed President Jeffrey Lacker might dissentThe forecast The updated forecast will include latest “central tendency” estimates for the unemployment rate, inflation and gross domestic product, which excludes the three highest and three lowest projections. In the latest forecast, released in December, the Fed forecast growth in a range of 2.6%-3.0% this year and next. The unemployment rate was expected to fall to 5.2%-5.3% in 2015 and then only inch lower in 2016 to a range between 5.2%-5.2%. Inflation was expected to remain soft this year, rising only 1%-1.6% but then move back to a 1.7% to 2% range in 2016. In 2017, the economy is expected to slow to a 2.3% - 2.5% rate, with the unemployment rate holding steady in a 4.9%-5.3% range and inflation near target in a range of 1.8%-2.0%. Some details of the forecast will also be closely watched. The Fed will release its updated estimate for the longer-run unemployment rate, which is what some Fed officials see as the lowest level the jobless rate can go without generating accelerating inflation. That estimate was 5.2%-5.5% in December. The jobless rate in February reached the high end of that estimate.The dot plot In the dot plot, the Fed will present the expected path for interest rates. In December, the median projections of Fed officials was for the federal fund rate to rise to 1.125% by December, 2.5% by the end of 2016, and 3.6% by the end of 2017. Another crucial detail will be if there is a revised estimate of the “longer-run” or “neutral” fed fund rates, a level that would allow the economy to continue to grow with inflation stable.The estimate for that rate was 3.75% in December. Many Fed watchers think the central bank will keep hiking rates to the neutral rate once they get started.The Yellen press conference Fed Chairwoman Janet Yellen will try to put her own spin on the results in an hour-long press conference starting at 2:30 p.m. Eastern. Economists think Yellen will try to calm market fears that the Fed will hike too quickly. She could repeat the language from her February testimony to Congress when she said that too many Americans remain unemployed or under-employed despite the improvement in the labor market.