Updated from 8:42 a.m. EDT

While the economy grew at a healthy clip in the third quarter, concerns about a slowdown over the next six months continue to linger.

A jump in consumer spending and strong business investment pushed gross domestic product up 3.7% last quarter, according to the Commerce Department. That was higher than the 3.3% pace recorded in the second quarter but below economists' forecasts for a 4.3% rise, as inventory accumulation slowed and the trade deficit widened.

Despite missing the estimates, economists weren't disappointed with the data. "The components of GDP were generally strong," said Sherry Cooper, chief economist at BMO Nesbitt Burns.

Indeed, consumer spending jumped 4.6%, up from just 1.6% in the second quarter, as automakers aggressively stepped up incentives. Meanwhile, business investment climbed 11.7% and spending on equipment and software rose 14.9%.

"The underlying data were stronger than the headline," said Paul Kasriel, chief economist at Northern Trust. "But that doesn't mean going forward that it's going to continue to be that strong."

In fact, Kasriel thinks growth will decelerate to between 3% and 3.5% in the fourth quarter and fall to just 2% in the first quarter, as consumption softens and inventories slow amid production cuts from the major automakers.

In recent years, consumer spending has been driven by disposable personal income, a drawdown of savings and increased borrowing. But Friday's data showed that real disposable income rose just 1.4% in the third quarter, down from 2.4% in the second. What's more, the personal savings rate fell to 0.4%, the lowest since the Great Depression.

"Households are not saving now and this is not sustainable," Kasriel said, adding that cash-out refinancings, which helped to boost spending in the past, are no longer helping out.

Other economists say higher energy prices could hurt growth going forward. "Continuing increases in oil prices in the fourth quarter will push growth slightly lower," said Jayanth Nazareth, an economist at J.P. Morgan.

While consumer spending could disappoint in the fourth quarter, the real slowdown won't be evident until the first quarter for reasons associated with the way the data are calculated. In September, the level of spending was above the third-quarter average, "so if we just stay at that level in October, November and December, you're going to get something positive," said Kasriel. "You've got arithmetic on your side."

Expectations for a rate hike in November were unchanged after the GDP report, with investors still calling for a 25-basis-point rate hike, even though inflation was extremely benign. The personal consumption expenditure price index rose just 1.1% in the third quarter, down from 3.1% in the second quarter. The core rate rose a meager 0.7%, the lowest in more than 40 years.

The price deflator increased 1.3%, down from 3.2% in the second quarter and below expectations for a 1.6% rise.

Meanwhile, the data Friday provided ammunition for both candidates in the upcoming election.

Republicans are able to point to a solid pace of economic activity in the third quarter, as well as an improvement in the University of Michigan's consumer sentiment survey from early October and an unexpected jump in the Chicago purchasing managers index.

Democrats, on the other hand, can highlight the government's employment cost index, which showed that wages and salaries have climbed just 2.4% over the past year, the smallest increase on record. And while sentiment has picked up from earlier in the month, it remains below the level seen in September.

Economists also note that forward-looking data point to slower growth ahead. The Conference Board's index of leading economic indicators has now fallen for four consecutive months.

"The seeds of a rather slower fourth quarter are sown," said Ian Shepherdson, chief economist at High Frequency Economics.

Shepherdson said he is looking for inventories to act as a drag on the economy in the months ahead. In the third quarter, inventories increased $48.1 billion, down from $61.1 billion. That change subtracted 0.48 percentage points from growth.

The burgeoning trade deficit is also expected to detract from GDP. Last quarter, imports increased at a 7.7% annual rate, while exports grew at a 5.1% rate. That subtracted 0.62 percentage points from growth.

Consumer spending added 3.23 percentage points to growth while business spending added 1.15 percentage points. Government spending increased at a 1.4% annual rate, the slowest in a year.

As for the UofM consumer sentiment index, it rose to 91.7 in late October from 87.5 earlier in the month. That was still down, however, from a level of 94.2 in September.

The Chicago PMI jumped to 68.5 in October, up from 61.3 in September and well above the estimates, which called for a reading of 59. The employment cost index increased 0.9%, slightly below the 1.0% level projected by economists.