RALEIGH — Average gas prices clicked a nickel higher overnight Wednesday in the Triangle and across the United States, and we can thank Hurricane Isaac for that.

After making landfall Tuesday in Louisiana, Isaac is slowly moving up the Mississippi River valley. Forecasters say its leftovers probably will bring rain into North Carolina by Monday.

But don’t worry. Fortunately, Isaac is no Katrina.

The storm is not expected to have an awful impact on most of our Labor Day holiday weekend – not on the weather, and not on gas prices.

“Right now people on the street are looking at retail gas prices and saying, ‘Wow, what’s going on? This storm is affecting my price,’ ” said Ben Brockwell, an analyst and administrator who explains these things for the Oil Price Information Service. “Don’t worry. It doesn’t look like it’s going to last long.”

Brockwell blamed that 5-cent spurt in gas prices Wednesday on cautious marketers who worried last weekend as Isaac moved into the Gulf of Mexico.

Concerned that the advancing storm might interrupt the flow of gasoline from Gulf refineries, they pushed a key wholesale price 21 cents a gallon higher between Friday and Monday. That’s what Triangle drivers felt when they tanked up Wednesday.

But this same wholesale number fell 20 cents between Monday and Wednesday, Brockwell said. That reflects an expectation that the refineries will resume operation quickly.

“The price surge that resulted from the storm in Gulf coast supply markets has subsided considerably,” Brockwell said Wednesday from his New Jersey office.

The weather forecast looks pretty good, until Labor Day itself.

“Most of the weekend is going to be pretty nice around here,” said Barrett Smith, a National Weather Service meteorologist in Raleigh.

A high-pressure system is expected to bring mostly sunny weather and highs in the upper 80s today through Saturday. Clouds will move in with a slight chance of thunderstorms Sunday, with rain increasingly likely Monday and Tuesday, Smith said. That’s when we can expect to feel Isaac’s wet remnants.

Regardless of Isaac’s impact, drivers can count on paying more at the gas pump than ever before at Labor Day – even more than seven years ago when Hurricane Katrina knocked Gulf refineries out of commission. Pump prices spiked into what then was record-high territory: an average $3.18 in the Triangle on Labor Day 2005.

Drivers would be glad to get that price today. Our gas prices have remained above $3.18 for the past 18 months. The Triangle average price for self-service regular Wednesday was $3.81 a gallon.

The AAA Carolinas motor club predicted Wednesday that gas price concerns will spoil travel plans for some of us. About 926,300 North Carolinians are expected to hit the road for the holiday weekend – about the same as last year, when gas prices were about 20 cents lower.

The Highway Patrol says it will use “Booze It and Lose It” checkpoints and stepped-up patrols to catch intoxicated drivers this weekend.

The state Department of Transportation will suspend most road and bridge construction work from Friday afternoon to Tuesday morning. Lane closings are expected only for three bridges — on U.S. 17 in Jacksonville, U.S. 158 in Elizabeth City and N.C. 32 in Chowan County south of Edenton.

Next week’s Democratic National Convention will close roads and cause traffic delays in downtown Charlotte beginning Sunday morning.

Siceloff: 919-829-4527 or blogs.newsobserver.com/crosstown or twitter.com/Road_Worrier/