The personal-consumption expenditures price index is the Fed's preferred inflation gauge, and the July numbers will drop at 8:30 a.m. ET this morning.

-- The 12-month PCE inflation rate is expected to come in at 3.6%, down slightly from 3.7% in June.

-- Setting aside volatile food and energy categories, the 12-month core PCE inflation rate is expected to be 3.3%, same as in June.

Because the report draws on other inflation data already published, the PCE numbers typically land very close to investors' forecasts. But it will put a fine point on the inflation problem facing the Fed ahead of a major address from Chairman Kevin Warsh on Friday.

The consumer-price index brought good news on July: Its core reading declined to a fairly moderate 2.5%. But PCE inflation, which varies in the emphasis it places on different spending categories, has been running quite a bit hotter.

Much remains unclear about how precisely Warsh views the inflation challenge he inherited. He has refrained from adding his economic projections to the quarterly dot plot that gathers Fed officials' forecasts, and hasn't weighed in on whether he might favor raising rates at coming meetings, a question that has split his central-bank colleagues.