(NEXSTAR) — The national average price of gas in the U.S. has surpassed $4 a gallon for the first time since 2008, and experts say it may not come back down for some time.

As of Sunday morning, AAA reports the national average sits at $4.009 per gallon, roughly 10 cents below the all-time record of $4.103 the U.S. hit in July 2008. Within the last week, gas prices jumped by about 41 cents alone, according to GasBuddy.

This time last year, Americans were paying roughly $2.76 per gallon, AAA data shows.

Rising crude oil prices amid the ongoing conflict between Russia and Ukraine are largely to blame for the price jump, experts say.

“This is a milestone that was hard to imagine happening so quickly, but with bipartisan support of severe sanctions on Russia, is not exactly surprising – it is the cost of choking off Russia from energy revenue,” said Patrick De Haan, head of petroleum analysis for GasBuddy, in a Saturday release. “As Russia’s war on Ukraine continues to evolve and we head into a season where gas prices typically increase, Americans should prepare to pay more for gas than they ever have before.”

Just last week, all 31 member countries of the International Energy Agency agreed to release 60 million barrels of oil from their strategic reserves “to send a strong message to oil markets” that there will be “no shortfall in supplies” as a result of Russia’s invasion of Ukraine. The U.S. is also having an “active discussion” regarding whether or not to ban Russian oil imports, The Hill reports.

Gas prices are expected to continue rising in the coming days and weeks. GasBuddy estimates the U.S. could be just days away from setting a new all-time record for the highest national average price.

In addition to Russia’s invasion of Ukraine, seasonal factors like increased demand, refinery maintenance, and a switch to summer-blend gas could send prices upward of $4.25 a gallon by Memorial Day, according to GasBuddy.

When gas prices are expected to peak

In December, GasBuddy released its 2022 forecast for what prices Americans could see at the pump. At the time, the company expected the national average to reach $4 per gallon by spring, which is really just a few weeks away.

However, GasBuddy has since revised its month-by-month gas price forecast. Here are the new ranges of possibilities for the national average we could see each month, without January and February:

• March: $3.70 – $4.24
• April: $3.84 – $4.38
• May: $3.98 – $4.51
• June: $3.93 – $4.48
• July: $3.91 – $4.45
• August: $3.83 – $4.62
• September: $3.81 – $4.58
• October: $3.76 – $4.37
• November: $3.65 – $4.23
• December: $3.52 – $4.03

The numbers above are the forecast for the national average, but prices will vary between states. In California, for example, prices are usually substantially higher than the national average. In states like Texas and Oklahoma, GasBuddy finds prices are typically lower.

GasBuddy’s report also includes price forecasts for 21 major cities. Of those, just three aren’t expected to hit a highest daily average of $4 per gallon: Dallas/Ft. Worth, Houston, and St. Louis. On the other end of the spectrum, Los Angeles, Sacramento, and San Francisco could see prices surpass $5.

Experts say other influences like the COVID-19 pandemic, supply chain disruptions, and severe weather make forecasting even more challenging and can alter the actual price at the pump.

The Associated Press and Nexstar’s Alix Martichoux contributed to this report.