NEW YORK (CNN/Money) - Rising oil prices lifted the U.S. trade deficit in the August, the government reported Thursday, but the gap between the nation's imports and exports was slightly below Wall Street expectations.

The Commerce Department report showed a $59 billion trade gap in August, up from a revised $58 billion in July. Economists surveyed by Briefing.com had forecast a gap of $59.5 billion for the most recent period.

The August trade gap was the third highest ever, trailing only the deficits recorded in February and June of this year.

The average price paid for a barrel of imported oil rose 7.4 percent to $52.65, the first time that measure has crossed the $50 threshold. The volume of crude oil imports also rose 4.4 percent, as those two things combined to raise the value of crude imports by $1.9 billion, or 12 percent, to $17.2 billion.

But helping to limit the trade gap was a solid gain in the nation's exports, which climbed $1.8 billion, or 1.7 percent, to a record $108.2 billion in the period. Civilian aircraft, semiconductors and drilling and oil field equipment were the categories that posted the largest gains in exports.

The trade gap with China, the largest imbalance with any U.S. trading partner, rose more than $800 million, or nearly five percent, to $18.5 billion in August.

Jay Bryson, international economist for Wachovia Securities, said he wasn't surprised by much in the report, and he does expect the trade gap to hit a record high before the end of the year, due to continued rises in oil prices and some of the impact from Hurricane Katrina.

"We could see a big decline in exports in September. The ports that got nailed by Katrina were more export oriented," he said, referring to grain and other agricultural imports that had trouble moving down the Mississippi River and out of the country through the Port of New Orleans.

The shutdown of U.S. refinery capacity in the wake of hurricanes Katrina and Rita have also led to increases in gasoline imports, a more expensive product than the crude oil imports they'll replace. And Boeing Co. (Research), the nation's largest exporter, was hit by a four-week strike in its commercial aircraft unit in September, which also could slow exports.

"I imagine we'll move into low 60's (billion dollar range), maybe even mid-60's, in next few months," Bryson said about coming trade gaps. February 2005 was the only time the trade gap has topped $60 billion, hitting $60.4 billion.

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