By Erwin Seba

HOUSTON, Aug 6 (Reuters) - U.S. refiners are expected to continue operating above 90% of their combined production capacity of 18.2 million barrels per day (bpd) in the third quarter, said analysts contacted by Reuters.

High refining margins are driving the continuing high levels of production from the second quarter into the third, but tropical storms could drive down production along the nation's refinery row on the coast of the Gulf of Mexico.

"Barring any significant unplanned outages due to hurricane activity or above average unplanned downtimes due to casualty events, I would expect third-quarter refinery utilization to be about 91% in the U.S. and 92% to 93% on the U.S. Gulf Coast," said John Auers, managing director at Refined Fuels Analytics.

On Wednesday, the U.S. Energy Information Administration said U.S. Gulf Coast refinery utilization reached its highest level since June 2023 at 9.8 million bpd, or 97% of the region's capacity.

The Atlantic hurricane season began on June 1 and continues through November 30. So far, four tropical storms, none of which has struck the Gulf Coast, have formed in the 2025 season, which multiple forecasters say will range between average and above average in the number of tropical cyclones.

U.S. refiners averaged 91% utilization in the second quarter and 95% utilization in July, according to an analysis of U.S. Energy Information Administration data.

"Refiners will run at or near as much as possible in the third quarter," said Andrew Lipow, president of Lipow Oil Associates. "They will run to the fullest extent, as close to maximum as possible while margins are good."

Top U.S. refiner Marathon MPC.N said it planned to operate its 13 refineries at 92% of their combined production capacity of 3 million bpd. In the second quarter, the company's refineries ran at 97% of capacity, the company said on Tuesday.

Marathon's refineries account for 16.5% of U.S. refining capacity.

No. 2 U.S. refiner Valero Energy Corp plans to operate its refineries up to 94% of their combined total capacity of 2.27 million bpd, the company said in late July.

(Reporting by Erwin Seba; Editing by Richard Chang)

((erwin.seba@thomsonreuters.com; +1 832 746 4269; Reuters Messaging: erwin.seba.thomsonreuters.com@reuters.net))