Oil prices leaped on Friday as the market fretted about global supply as rough weather in the Caribbean Sea threatened to develop into a hurricane in the oil-producing Gulf of Mexico.

New York’s main contract, light sweet crude for August delivery, surged to US$78.86 a barrel, a gain of US$2.35 from Thursday’s close.

In London, Brent North Sea crude for August delivery gained US$1.65 to settle at US$78.12 a barrel.

“The biggest influence is really the weather forecast for the tropical waves that are occurring in the Caribbean and whether those will develop into a tropical storm and ultimately a hurricane next week,” said Andy Lipow at Lipow

The market kept a watchful eye on signs of a brewing tropical storm that could wreak havoc on the oil companies operating in the Gulf.

“That could impact oil production,” Lipow said.

The rough weather could impact crude oil that is produced offshore Mexico or, if the storm heads northward toward the Louisiana coast, it would impact the oil production in the US, he said.

JPMorgan Chase analysts noted that if the low-pressure system developed into a tropical cyclone, it would likely disrupt operations to contain and clean up the BP spill, and might reduce production.

A tropical storm “would undoubtedly interrupt BP’s oil spill response, and were it to strengthen sufficiently, a storm could possibly interrupt Gulf of Mexico oil and gas production,” they said in a note to clients.