Marine Thunderstorm Wind · Gulf of Mexico

The Weatherflow mesonet XGIM on Grand Isle measured a thunderstorm wind gust of 40 mph or 35 knots.

On December 28, 2024, a potent storm system traversed the southeastern United States, significantly impacting southeastern Louisiana, southern Mississippi, and adjacent coastal waters. The Storm Prediction Center had issued a moderate risk (level 4 out of 5) for severe weather in these areas, anticipating the development of supercell and QLCS thunderstorms capable of producing strong tornadoes and damaging wind gusts. Meteorologically, a pronounced shortwave trough advanced eastward, interacting with a moist and unstable air mass characterized by surface dew points in the upper 60s to lower 70s Fahrenheit. This setup resulted in high convective available potential energy (CAPE) values between 1500 and 2000 J/kg and substantial low-level wind shear, fostering an environment conducive to severe thunderstorms and tornadoes. Throughout the day and into the evening, multiple tornadoes were reported across the region, leading to significant structural damage, particularly in parts of southeastern Louisiana and southern Mississippi. In addition to tornadoes, these storms produced straight-line winds exceeding 70 mph, causing widespread power outages and hazardous conditions on both land and coastal waters. The severe weather threat persisted into the night as the storm system continued its eastward progression.