How Hurricane Isaias broke through to become the first Atlantic hurricane in an eerily quiet 2026 season

Hurricane Isaias became the first Atlantic hurricane of 2026 on October 7, breaking a record for the latest-forming first hurricane in over a century. It tied with a 1905 storm for this unusual milestone. By October 8, Isaias was moving through the central Gulf of Mexico, threatening the northern Gulf Coast with landfall expected late on October 9 or early October 10. The storm’s rain bands were concentrated to the northeast of its eye, pushed by strong winds, which made the storm lopsided. Residents in Alabama and the Florida Panhandle began preparing for damaging wind, rain, and storm surge, while Tyndall Air Force Base in Florida started evacuating fighter jets due to the approaching hurricane.

The unusually quiet start to the 2026 Atlantic hurricane season was largely caused by El Niño, a climate pattern that occurs every few years when ocean surface temperatures in the central and eastern Pacific Ocean heat up. El Niño influences weather worldwide, including Atlantic hurricanes. In 2026, El Niño was already strong by late summer and expected to become one of the strongest on record. This warming creates more thunderstorm activity over the eastern Pacific, which in turn increases westerly winds across the tropical Atlantic. These winds disrupt the formation of hurricanes by creating vertical wind shear, where winds near the surface blow from the east while winds at higher altitudes blow from the west, tearing apart storm systems.

El Niño also causes air to sink and become dry over the tropical Atlantic, which is another barrier to hurricane formation. Hurricanes require moist air to develop, so dry air makes it harder for storms to form. In 2026, most storms that did form in the Atlantic occurred north of the region affected by wind shear and dry air, but storms at these higher latitudes rarely become strong hurricanes. Typically, the strongest hurricanes form farther south in the Caribbean, where conditions are more favorable. The map of 2026 storm tracks shows that Isaias was the ninth storm of the season, and its formation in the western Gulf of Mexico was an exception to the usual pattern.

Isaias formed in the western Gulf of Mexico, rather than the deep tropics where most strong hurricanes originate. This region experienced weaker vertical wind shear and a small area of enhanced moisture in early October, creating conditions more favorable for hurricane formation. Additionally, exceptionally warm ocean water provided the necessary fuel for the storm. Isaias organized rapidly in this environment, but as it strengthened, vertical wind shear began increasing again due to the jet stream, which tends to dip farther south as autumn progresses. This shear limited Isaias’ potential strength, even though it remained a dangerous storm.