California gasoline prices

The average price of a gallon of regular gasoline in California on Friday was $4.062, up 7.6 cents since last week, according to the AAA Fuel Gauge Report. (Frederic J. Brown / AFP/Getty Images / October 10, 2012)

Summer is coming. The long Memorial Day weekend is just two weeks away and, of course, average gasoline prices in California are back up above $4 a gallon.

On Friday, the average price of a gallon of regular gasoline in California was $4.062, up 7.6 cents since last week, according to the AAA Fuel Gauge Report.

You can round up the usual suspects: Refineries say their supplies are tight.

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In fact, some analysts, such as Patrick DeHaan of GasBuddy.com, said that "tight gasoline supply exists especially along the West Coast."

This is at a time when U.S. exports of refined fuels to customers overseas remain near historically high levels.

California is currently in a close race with Alaska ($4.071 a gallon) for the not-so-coveted rank of second-most-expensive gasoline in the nation. Hawaii is No. 1 at $4.353 a gallon.

That's even as fuel consumption in California continues an impressive downward trend over much of the last three years, according to the state's Board of Equalization.

There are other explanations too.

"Pump prices are now feeling the effect of a wholesale spot price spike that happened in late April and early May in response to reports of low inventory," said Jeff Spring, a spokesman for the Auto Club of Southern California.

Spring said the current price rise may be short-lived, but other observers are more skeptical.

Charles Langley, public advocate for the Utility Consumers Action Network in San Diego, delivers a weekly prediction of California fuel prices, called the "gougecast." On Thursday afternoon, he was only half-joking when he said that "we predict a high probability of a refinery shutdown or disaster soon."

A few hours later, BP's Carson refinery, the state's third-largest -- with a capacity of 240,000 barrels of fuel a day, performed a partial and unscheduled shutdown. Bob van der Valk, an independent fuel price specialist, said production at the Carson refinery declined by about 45,000 barrels a day.

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