Don't pay too much attention to what Jerome Powell says today

London(CNN Business) The big event for investors on Friday is in Jackson Hole, Wyoming, where Federal Reserve Chair Jerome Powell will speak about the economy at a gathering of central bankers.

Wall Street will be hanging on to Powell's every word for clues about just how big the Fed's next rate hike will be.

The problem? The Fed itself has indicated that it doesn't know yet.

"Because we're uncertain, we're desperate for some kind of signal from the Fed," David Bianco, Americas chief investment officer at DWS, told me. "But they don't have clarity themselves on it."

Quick rewind: The Federal Reserve started raising interest rates in March in a bid to bring down inflation. At its past two meetings, it's hiked interest rates by three-quarters of a percentage point, an unprecedented move in the central bank's modern history.

Investors have been increasingly hopeful that the Fed could ease up from here, especially after inflation slowed slightly last month. Consumer prices rose 8.5% in the year to July, down from 9.1% in June.

That's the big reason US stocks have rallied this summer. The S&P 500 is up about 15% from its June low.

But when Fed officials have actually talked about their plans, they've made clear that they're in wait-and-see mode.

"We anticipate that ongoing increases in the target range for the federal funds rate will be appropriate," Powell said in late July. "The pace of those increases will continue to depend on the incoming data and the evolving outlook for the economy."

In short, the Fed's decision at its next meeting on Sept. 20 and 21 hinges on the economic numbers due to arrive in the coming weeks, including the August jobs report and the latest Consumer Price Index.

The most recent edition of the Personal Consumption Expenditures Price Index, which is the Fed's preferred measure of inflation, hits later this morning. It's expected to show that core inflation, which strips out volatile food and energy prices, ticked down to 4.7% in July from 4.8% the previous month.

"I don't think we should try to read too much into whatever is said at Jackson Hole," Bianco said. "They are just as uncertain about these things as we are."

Wall Street's view: Investors now think that the likelihood that the Fed will hike rates by three-quarters of a percentage point for a third consecutive meeting is over 60%. One week ago, they put the odds at 47%.

That indicates markets could be choppy in the coming weeks as traders try to pin down just how aggressive the Fed will be. But given the time left on the clock for the situation to change again, investors shouldn't expect Jackson Hole to yield a lightbulb moment.

Mortgage rates are back on the rise

Mortgage rates jumped higher this week as investors tried to make sense of data that gave mixed signals about the health of the US economy.

The latest: The 30-year fixed-rate mortgage averaged 5.55% in the week ending August 25, up from 5.13% the week before, according to Freddie Mac. That's almost double where it was this time last year, my CNN Business colleague Anna Bahney reports.

After starting the year at 3.22%, mortgage rates rose sharply during the first half of the year, hitting a high of 5.81% in mid-June. Since then, concerns about the economy and the Federal Reserve's mission to combat inflation have clouded the picture.

The combination of higher mortgage rates and the slowdown in economic growth has been weighing on the housing market, said Sam Khater, Freddie Mac's chief economist.

"Home sales continue to decline, prices are moderating and consumer confidence is low," he said. "But, amid waning demand, there are still potential homebuyers on the sidelines waiting to jump back into the market."

Up and down: Mortgage rates tend to track rates for the benchmark 10-year Treasury, which advanced last week. Rates have swung in recent weeks as investors have digested a slew of data that shows the economy is resilient in some areas and softening in others.

After skyrocketing during the first part of the year, new mortgage payments came down slightly in July from June, according to a survey from the Mortgage Bankers Association.

Still, the cost of a mortgage is up sharply, which could make it harder for buyers to spend their money on other things.

A year ago, a buyer who put 20% down on a $390,000 home and financed the rest with a 30-year, fixed-rate mortgage at an average interest rate of 2.87% had a monthly mortgage payment of $1,294, according to Freddie Mac. Today, a homeowner buying the same priced house with an average rate of 5.55% would pay $1,781 a month. That's a $487 increase.

Even dollar stores are feeling the inflation pinch

Dollar stores built their brand by offering inexpensive products to bargain-hungry shoppers. But even Dollar General (DG) and Dollar Tree (DLTR) are starting to feel the pinch of a slowing economy.

The companies reported solid increases in sales for the second quarter on Thursday, my CNN Business colleague Paul R. La Monica reports. But both firms raised concerns about the impact that inflation may have on future results.

Dollar Tree CEO Mike Witynski said in the company's earnings release that shoppers are being "pressured by higher costs for food, fuel, rent and more."

"Consumers continue to be burdened by levels of inflation not experienced in decades," he told analysts. The company's suppliers are getting battered by inflation, too.

Meanwhile, Dollar General CEO Todd Vasos described the quarter as a "period of inflation and economic uncertainty."

On the radar: Dollar Tree is also dealing with some customer backlash following last year's controversial decision to raise prices, a move that spurred some consumers to derisively refer to the chain as "$1.25 Tree."

Still, they're faring better than other retailers as households rethink their budgets. Shares of Dollar Tree fell 10% on Thursday but are still up 6% year-to-date. Dollar General's stock is up more than 4% in 2022.

Up next

The PCE Price Index arrives at 8:30 a.m. ET. Fed Chair Jerome Powell's Jackson Hole speech follows at 10 a.m. ET.

Coming next week: How is America's jobs market holding up? Economists expect to learn that another 290,000 jobs were added in August, another solid showing after more than half a million positions were created in July.