You might want to fill up today. Gas prices likely will reach $3 a gallon by the weekend.

Today would be a good day to fill up your gas tank.

Pump prices in Milwaukee and Wisconsin will almost certainly rise in the coming days, with most stations at or above $3 a gallon by the weekend, an industry analyst says.

The higher prices are part of an intricate geopolitical maze that has sent global crude oil prices up by $6.50 a barrel in a month and nearly $20 a barrel this year.

Global crude oil prices have probably leveled off, “but you’ve still got some catch-up to do at the pump,” said Jim Ritterbusch, president of Ritterbusch and Associates, an oil trading and advisory firm with offices in Chicago and Galena, Illinois.

In the Milwaukee area, “You’ll probably see $3 at a number of stations maybe by the weekend, if not in a couple of weeks,” Ritterbusch said.

The national average for a gallon of regular gas is $2.87, according to travel organization AAA. In Wisconsin, the average is $2.83. Milwaukee is right at the $2.87 national average.

At least one station in Milwaukee was already above $3 a gallon on Wednesday and several were sitting at $2.99, according to gasbuddy.com. 

Elsewhere in Wisconsin, Green Bay, Appleton and Fond du Lac are all averaging about $2.76 for a gallon of regular. Oshkosh is at $2.81 and Wausau is at $2.85, according to AAA.

The highest gas prices in the nation are in California, where a gallon of regular is averaging $4.04, according to AAA. The average price in Chicago is $3.34.  

The rising prices are all part of a  complicated global drama, the latest act having occurred this week when the Trump administration moved to enforce sanctions on Iran by curtailing its oil exports.

"Major producers have worked hard to bring the oil market into balance," Ethan Bellamy, a managing director and senior petroleum industry analyst at Milwaukee-based Robert W. Baird & Co., said in an email. "Yanking Iran out of the global supply picture by eliminating sanctions waivers will require producers to reshuffle, but the Iranian supply isn’t the only issue."

Iran has threatened to respond with a blockade of the Strait of Hormuz, a vital shipping route that connects the Persian Gulf with the Arabian Sea and Indian Ocean.

"That could create a major conflict at the heart of world oil production, which threatens much more than just Iranian exports," Bellamy said.

All the while, oil producing countries have worked to limit production in order to raise prices, Ritterbusch said.

"We had a sizable supply surplus (of oil) at the beginning of this year and that has basically been erased," Ritterbusch said. "That’s the main reason (prices) have gone up.

"The Saudis, combined with involuntary production declines out of Venezuela, have taken a lot of barrels off of the market this year," he added.

Venezuela's government is essentially in meltdown and Saudi Arabia is seeking to use increased oil revenue to eliminate big budget deficits. 

Saudi Arabia has an oil-based economy and possesses about 16% of the world's proven petroleum reserves. It is the world's largest exporter of petroleum, which accounts for about 87% of its budget revenue and more than 40% of its GDP.

It has been working carefully to raise oil prices in order to stabilize its economy. 

Meanwhile, China is a huge importer of Iranian oil. The Chinese may use sanctions as a bargaining chip in U.S. trade talks.

"A lot of these things are intertwined," Ritterbusch said. "It’s going to be interesting to see how it all plays out."

In oil-rich areas of the U.S, the prices will spur producers to increase production. 

U.S. producers "are certainly not maxed out," Ritterbusch said. "They are going to have incentive to crank things up a notch.

"They have been very cautious so far," he added. "Most of them didn’t think this price advance would go as far as it did and last as long as it did. I think you’re going to see the drilling rig counts increase appreciably in the coming months."

New drilling technology has allowed the U.S. to become the world's top producer of crude oil.

Increased U.S. production will help keep a lid on further oil price increases, assuming the geopolitical landscape remains as is.

As far as higher oil prices impacting the U.S. economy, we probably aren't there yet, Bellamy said. 

"With the U.S. producing so much oil, and so much economic activity from the oil and gas supply chain, rising prices likely offset some negative impact on economic activity," Bellamy said.

He described the range of $50 to $75 a barrel as "the Goldilocks zone" for oil prices.

"Above $75, gas and diesel prices for consumers and industry likely start to curtail economic activity," Bellamy said.

"There’s also a function of how fast prices rise. If it’s a slow climb, consumers have time to adapt, but a price shock is much harder to digest."

Contact Joe Taschler at (414) 224-2554 or jtaschler@gannett.com. Follow him on Twitter at @JoeTaschler or Facebook at facebook.com/joe.taschler.1.