SAN DIEGO – If you were enjoying the recent low gas prices across California, brace yourself because you will start paying more again.

The nonprofit group Consumer Watchdog warned Souther California drivers on Thursday that they would be facing sticker shock at the gas pumps beginning this weekend.

The group said the state's biggest oil refiners raised wholesale prices charged to station owners by 37 cents.

The price hike goes with the transition to summer blends of gasoline, which are being delivered by oil refiners to branded gasoline stations beginning Thursday.

“Drivers in Southern California should fill up now because gasoline prices are going up quickly and not coming back down for a while,” said Consumer Watchdog president Jamie Court.

Consumer Watchdog said that deals could still be had at Costco and unbranded independent stations for the next few days, but that prices at branded stations would have to change with deliveries of gasoline beginning Thursday.

As of today, California gasoline prices are still 68 cents higher than the U.S. average. The coming price spike will grow that gap and continue to fuel record profits for oil refiners in the state, said Consumer Watchdog.