Tropical Storm Isaias forecast to hit US Gulf coast as hurricane early Saturday

​Tropical Storm Isaias formed in the Gulf of Mexico on Wednesday and is forecast to strengthen into a hurricane before slamming into the southern US coast early on Saturday, bringing heavy rains, storm surges, and possible tornadoes across several states, the National Hurricane Center said. The storm is expected to pass through areas ‌with significant offshore oil and gas production, along with onshore refining facilities, which could pressure inventories and already-high prices at the pump.

Michael Brennan, director of the NHC, said in a video briefing on Wednesday that Isaias could be a "major" hurricane — Category 3 or higher — when it makes landfall and could have "multiple, life-threatening impacts from storm surge, heavy rainfall flooding and hurricane force winds." Isaias would be the first hurricane of the season in the Atlantic, ‌according to the NHC, and could tie the record for the latest first Atlantic hurricane with one that hit on October 8, 1905. The strong El Nino weather pattern this year has suppressed ‌Atlantic hurricane development by increasing vertical wind shear, which disrupts the formation of strengthening tropical storms.

About 11.2 million barrels of oil production could be lost across the Gulf through the duration of the storm, a marked increase from the 7.1 million barrels impacted by Tropical Storm Bertha in July, according to a model forecast from consulting firm Earth Science Associates. QUICK DEVELOPMENT, TORNADOES

The NHC expects Isaias to develop into a hurricane by Thursday as it quickly picks up power over the warm Gulf waters before making landfall early ⁠on Saturday, most ​likely somewhere along the Mississippi, Alabama or Florida panhandle ⁠coast. The storm was located about 500 miles (805 km) south of the Louisiana coast early on Wednesday. Isaias could produce isolated rainfall amounts of 10 inches (25.4 cm) across parts of the Gulf Coast, stretching from Louisiana to the Florida Panhandle, the NHC said ⁠in its latest bulletin.

Tornadoes are possible in the rainbands of Isaias across the Florida panhandle and Alabama from Friday evening through Saturday, with more tornadoes expected further inland as the storm moves north. The storm could also produce 3 inches or ​more of rain further inland, with the NHC warning that "flash and urban flooding, along with isolated river flooding, will be possible" across the Southeast.

Isaias is expected to run into strong upper-level winds, known ⁠as vertical wind shear, in the final 24 hours before it reaches the northern Gulf Coast, which could weaken the storm. Still, the NHC says it is “looking more likely that Isaias will be a significant hurricane when it reaches the coast.”

Florida Governor Ron DeSantis ⁠on ​Tuesday had already declared a state of emergency for portions of the state. Some officials across the region were urging residents to voluntarily evacuate. Florida US Senator Rick Scott wrote on social media that he had spoken with President Donald Trump about the storm, and that "the federal government is going to show up for Florida and make sure we have everything needed to prepare, respond, and recover."

IMPACTS ON OIL, GAS The ⁠Marine Minerals Administration, which monitors offshore oil and gas operators in the Gulf of Mexico, said on Wednesday that personnel have been evacuated from eight production platforms and two non-dynamically positioned ahead of the ⁠storm.

About 25% of current oil production in the Gulf, ⁠or 511,619 barrels of oil per day, has been shut in, the agency said, citing operator reports. Just over 350 million cubic feet per day of natural gas production has also been shut in, or about 16.4% of total output from the region. The companies with the most exposure to the storm ‌include BP , Chevron, ENI, Murphy Oil ‌and Shell