Isaias has strengthened into the first hurricane of the Atlantic season as it moves across record-warm waters toward the northern US Gulf Coast, forcing schools and local authorities to close.
According to the Miami-based National Hurricane Center (NHC), the storm is expected to make landfall in the Florida Panhandle, southern Alabama and southern Mississippi late Friday or early Saturday. Low-lying areas are especially vulnerable to flooding and storm surge.
The center warned residents in potentially affected areas on Thursday to complete all emergency measures to protect life and property without delay.
The NHC has also issued a hurricane warning from Bay St. Louis, Mississippi, to Indian Pass in northwestern Florida amid the threat of torrential rain and a significant risk of localized flash flooding and urban flooding.
Rainfall is forecast at 3-6 inches, with isolated totals up to 10 inches.
"We are forecasting Isaias to be a dangerous hurricane at landfall," Michael Brennan, director of the National Hurricane Center, said in a Thursday morning update, adding that he expects the storm could reach "near-major hurricane intensity" on Friday as it moves north over Mexico's Yucatan Peninsula.
On Thursday morning, Isaias had maximum sustained winds of nearly 130 km/h (80 mph), with stronger gusts. Heavy rain and flash flooding also threaten inland areas through the weekend, reaching as far as the Tennessee Valley and potentially covering a broad region from the inland Southeast up to the southern Appalachians.
Ahead of the storm, oil and gas producers have shut in a significant portion of offshore operations in the US Gulf of Mexico, a region that accounts for nearly 15% of US annual crude oil production.
As of Wednesday, about 25% of the region's oil output had been suspended, taking some 511,000 barrels per day off the market, according to the Bureau of Safety and Environmental Enforcement. The agency said 8 of the 371 crewed oil platforms in the Gulf had been evacuated.
With oil prices already high, the production cuts are large enough to affect the market, though other Gulf storms have caused bigger disruptions, said Jim Burkhard, global director of oil market research at S&P Global Energy. Of greater concern, he said, is whether Isaias makes landfall with force near refineries.
When Isaias was declared a hurricane on Wednesday, it was the latest date in 121 years that a first Atlantic hurricane of the season had formed, trailing only the record set in 1905, according to data from the US National Oceanic and Atmospheric Administration. The hurricane season typically runs from June 1 to November 30.
