National and international supply problems, an approaching hurricane and an upcoming holiday weekend affected gas prices throughout the country Tuesday and helped pushed Lexington near the $4 threshold for a gallon of regular unleaded.

The majority of gas stations in the city were selling regular unleaded for $3.95 a gallon Tuesday, a price not likely to fall by much until after Labor Day, when gas prices typically spike due to increased demand, said Christopher Oakford, spokesman for AAA of the Bluegrass.

The increases were spurred by fears that Hurricane Isaac could damage oil rigs in the Gulf of Mexico. About 25 percent of rigs and some tanking operations had stopped to prepare for the hurricane, Oakford said.

An explosion at Venezuela's largest oil refinery Saturday, which reportedly killed more than 40 people, also created shortages.

Oakford said gas prices would probably fall after the holiday weekend, and he encouraged motorists to "keep their eye on the longer picture."

"This will be a short-term thing, provided of course that Isaac doesn't cause a lot of damage to the refineries," he said.

Josh Kegley: (859) 231-3197. Twitter: @HLpublicsafety.