Crude oil futures prices settled modestly higher Thursday, pulled up by gasoline futures, which soared 3.1% on fears that Hurricane Irene could disrupt supplies along the East Coast.

The National Hurricane Center said Hurricane Irene, packing 115 miles-per-hour winds, remains on a track that will bring it to the North Carolina coastline by Saturday morning at major hurricane strength, then skirt the eastern seaboard and an approach to the southern coastline of New Jersey by Sunday morning. In its 2 p.m. EDT advisory the NHC said Irene, which is now off the eastern Florida coastline, should remain on a course to run up the eastern coastline of the U.S. and major population centers. A direct hit on New York City is possible later Sunday, the NHC said.

"It's all about Irene and concerns about threats to infrastructure from flooding or loss of power," said Andy Lebow, a vice president at brokerage MF Global in New York. "There's a lot of infrastructure up here from terminals to vessels, pipelines and refineries."

About 1.6 million barrels of operable crude oil refining capacity, or 9% of the U.S. total, is located on the East Coast, according to the Energy Information Administration.

Crude oil prices dropped to a low of near $83 a barrel, the weakest price since Monday, as U.S. equity prices traded lower. But the strong gains in gasoline "reluctantly dragged it up," said Lebow.

Light, sweet crude oil for October delivery settled 14 cents higher, at $85.30 a barrel on the New York Mercantile Exchange. ICE Brent crude for October delivery settled 47 cents higher, at $110.62 a barrel. Brent has been supported by Tuesday's news that Royal Dutch Shell (RDSA, RDSA.LN) has declared force majeure on exports of Nigerian Bonny Light crude oil through October after fresh episodes of pipeline sabotage attributed to civil unrest in the Delta oil producing region.

Latest inventory data from the EIA show East Coast stocks of finished gasoline, or fuel that is immediately available for use in cars, was 9.3% below their five-year average for the week ended Aug. 19. But total gasoline stocks, which include blending components that would be used to produced finished gasoline, are in line with five-year average levels.

Traders said current inventories don't create a concern if there isn't any disruption to the multi-link supply chain. Still, with the contract for Nymex September reformulated blendstocks futures expiring next Wednesday, any storm-related outages could cause a continued price spike through expiration day.

Nationwide, U.S. crude oil processing at refiners hit a four-year high for late August. But since then, a fire reduced operation at a crude processing unit at Sunoco's 335,000 barrels a day Philadelphia refinery.

With one eye on the menacing storm, traders also will be fixated on Federal Reserve Chairman Ben Bernanke's speech to the central bank's annual retreat in Jackson Hole, Wyo., Friday. At the event last year, Bernanke signaled a second round of stimulus measures, sparking a months-long rally in stock and commodity markets. "We've got the clouds over Bernanke and the real storm to watch," said MF Global's Lebow.

September gasoline futures settled 3.1%, or 8.95 cents a gallon, higher at $2.9679 a gallon, the highest price since Aug. 2. The single-day gain was the biggest since Aug. 10.

September heating oil futures settled 2.48 cents higher, at $2.9855 a gallon, the highest price since Aug. 3.