Oil dropped Friday, contributing to a weekly decline of nearly 5% for the U.S. benchmark, as traders tracked Tropical Storm Nate’s path into the Gulf of Mexico and its potential impact on the region’s energy infrastructure. “As we come into the weekend, the market is focusing on the implications of Tropical Storm Nate and how big any disruptions will be” on crude production and refining capacity, said Richard Mallinson, an analyst at consultancy Energy Aspects.

November West Texas Intermediate crude fell $1.50, or 3%, to settle at $49.29 a barrel on the New York Mercantile Exchange. Prices, which saw their lowest finish since mid-September, finished around 4.6% lower for the week, after posting gains in each of the last four weeks. December Brent crude the global oil benchmark, fell $1.38, or 2.4%, to $55.62 a barrel on London’s ICE Futures exchange. The contract ended about 2.1% lower for the week.