Gasoline prices in the Midwest may start to rise as a result of regional refinery issues, the top analyst at GasBuddy.com said Thursday.

Gasbuddy.com reports regional prices of as low as $3.33 for a gallon of regular unleaded gasoline. Gas prices have been on a general decline for the last month, though Patrick DeHaan says the low prices might not last.

Planned maintenance at the BP refinery in Whiting, Ind., and Exxon Mobil's refinery in Jolliet, Ill., may create some regional issues that could lead to some seasonal spikes at the gasoline pump. Prices hikes have already been felt across much of the West Michigan area, he said.

"This is not the normal price cycle," he told WOOD Radio News. "It's been aggravated by these refinery issues."

The state-wide national average prices in Michigan is $3.44, down from the $3.61 average reported on this day last year.

DeHaan says prices could go up in the region by another 20 cents, which would put them in line with the seasonal average.

"It may take a couple weeks before supplies recover as refiners finish up their work," he said.

Gasoline prices typically start to decline in September after refiners switch to a winter blend of gasoline, which is less expensive to produce.