The national average price for a gallon of regular gasoline jumped 5 cents in the past week to $3.87 per gallon Friday, AAA Mid-Atlantic said in a news release.

“We’re seeing the highest (or close to) gas prices of the season this week in a rare September upswing,” said Tracy Noble, spokesperson for AAA Mid-Atlantic. “

The price is 16 cents more than one month ago, 24 cents more than a year ago, but still 24 cents below the record high of $4.11 set in July 2008.

According to AAA Mid-Atlantic, crude oil prices soared to four-month highs due to a series of factors, both domestic and international. The Federal Reserve announced another stimulus move to jump start a struggling U.S. economy, boosting crude prices just shy of the $100 mark Thursday. Internationally, geopolitical tensions escalated in the Middle East following the killing of U.S. ambassador to Libya, J. Christopher Stevens. In addition, Germany’s top court approved the Eurozone’s bailout fund and fiscal pact, causing the euro to gain momentum and subsequently pressured the U.S. dollar downward. Crude oil closed the week at $99.06 on Friday.

AAA Mid-Atlantic said this September jump in prices was also fueled by a “perfect storm” of refining issues – two major Midwest refineries are being upgraded to handle heavy Canadian crude oil and will require partial shutdowns over the next few months; oil companies in the Gulf of Mexico have been slow to restart after shutting down for Hurricane Isaac, the impact of which is now being felt at the pumps.

Noble said the recent increases will be short-lived and decreases should begin inthe middle of September and continue for the last few months of the year as demand decreases and the switch to less expensive winter-blended gasoline begins.