Gasoline prices in Maine have begun a sharp increase that is expected to accelerate in the coming weeks, according to a national gas-price analysis firm.

The average price per gallon for regular unleaded gas in Maine was about $2.34 a gallon as of late morning Thursday, up 6 cents from the previous day and 22 cents more than the average price in January, according to Brooklyn Park, Minnesota-based GasBuddy.com.

The ongoing price increase is expected to accelerate over the coming two to three weeks as part of an upward trend nationwide, the company said.

“Wednesday brought a big price rally in gasoline markets and gasoline wholesalers are seeing huge increases,” GasBuddy senior petroleum analyst Patrick DeHaan said in a news release. “Wholesale prices today alone have increased coast to coast from 10 to 27 cents per gallon; and when you add that on top of the increases that occurred earlier this month, it’s inevitable that retail prices will climb aggressively in weeks ahead.”

While some of the price spike is attributed to the seasonal decline in gasoline inventory, reduced refinery output and the shift to summer grades of gasoline, there have also been significant operational issues at refineries in five states, according to GasBuddy.com.

A United Steelworkers Union strike that began Feb. 1 has exacerbated operations at 12 refineries where work stoppages have been imposed in California, Texas, Louisiana, Indiana, Kentucky and Ohio, it said.

“Volatility is the name of the game right now and we expect that to translate into 10-cent increases in retail gasoline, week after week over the next two to three weeks, with larger, more immediate increases in West Coast areas,” DeHaan said.

In the Northeast, weather-related issues also have contributed to the ongoing price spike, said Patrick Moody, spokesman for AAA Northern New England.

“The bitter cold has caused some problems at a number of refineries, as well,” he said.

Despite the sharp rise in gas prices, the average price per gallon in Maine still was down about $1 from a year earlier, Moody said. Still, that’s down from the peak price difference on Jan. 26, when the average gas price in Maine was $1.26 less than it had been a year earlier, he said.