CHICAGO (CBS) — If you’ve filled your gas tank Thursday, you probably noticed a sudden spike in prices.

As WBBM Newsradio’s Regine Schlesinger reports, a Chicago oil analyst is at a loss to explain it.

LISTEN: WBBM Newsradio’s Regine Schlesinger reports

At some Chicago gas stations, just overnight, the prices jumped 14 cents a gallon.

Analyst Phil Flynn with PFGBEST in Chicago says there is no logical reason.

“Usually when you see this type of spike, it’s usually due to a refinery outage or something like this, but to get this kind of a spike ahead of the holiday, this dramatic, to me, is quote surprising,” Flynn said.

Flynn’s best guess for the sudden rise is dealers capitalizing on the expected crush of holiday travelers this weekend.

Flynn says this year has been a disaster for gas prices, which soared on news of the war in Libya and other events. But in recent weeks, prices have come down sharply, which makes the sudden jump all the more baffling.