Oil rallied and gasoline surged to a five-month high as energy companies suspended offshore operations and refiners shuttered Gulf Coast plants with Tropical Storm Laura expected to strengthen into a hurricane before making landfall later this week.

Around 82% of oil production in the Gulf of Mexico was halted by around midday Monday, with refinery closures from companies including Motiva Enterprises LLC and Valero Energy Corp. potentially shutting in more than 1 million barrels a day of capacity. Gasoline futures rose to their strongest level since before the pandemic on concern over possible fuel shortages. Meanwhile, oil futures rose 0.7% in New York and 1.8% in London.

“The market as of right now is very worried about a shortage of gasoline, and that’s a serious consequence from the storm,” said Bob Yawger, director of the futures division at Mizuho Securities USA.

The storm comes as U.S. benchmark crude futures have risen this month amid a streak of declines in U.S. crude stockpiles and gasoline inventories. However, the pandemic is still raging across the world, threatening a sustained rebound in consumption.

“Signs of rising cases in Europe and Asia are still weighing on global demand expectations,” TD Securities commodity strategists including Bart Melek wrote in a note. “Weak refinery runs, exports and distillate demand continue to put a damper on the recovery.”

Laura could also have ramifications for global oil flows. Shuttered U.S. refineries could boost gasoline flows from Europe to the U.S. East Coast, depending on how badly plants are hit and whether Colonial Pipeline Co.’s conduit is affected, according to Steve Sawyer, director of refining at energy consultant FGE.

The storm threat has translated into higher premiums for crudes in the region. Mars Blend rose $1.25 on Monday to $2.85 a barrel over Nymex WTI futures, its highest premium since May, according to data compiled by Bloomberg. WTI crude in Houston rose to its strongest level since July.