El Niño's Grip: Hurricane Season Forecast Shifts

The Eastern Pacific hurricane season, which commenced on May 15, is projected to experience increased activity due to the onset of an El Niño climate pattern. This phenomenon, characterized by warming Pacific Ocean waters, creates conditions conducive to tropical cyclone development by reducing vertical wind shear.

Conversely, the Atlantic basin is expected to see a statistically below-average hurricane season as El Niño induces cooler waters and heightened vertical wind shear, inhibiting storm formation.

The Eastern Pacific

During an El Niño phase, warmer ocean temperatures in the Eastern Pacific provide the necessary energy for tropical systems to form and maintain their structure. The reduced vertical wind shear prevents developing storms from being disrupted, allowing them to intensify. The last El Niño in 2023 saw 20 tropical systems in the Eastern Pacific, with 17 becoming named storms, including Hurricane Hilary, which caused over $900 million in damages in the U.S. and Mexico.

In contrast, the Atlantic Ocean experiences an opposite effect during El Niño. Increased vertical wind shear and relatively cooler waters in the Atlantic basin typically suppress tropical storm and hurricane development. This dynamic suggests a lower probability of above-average hurricane activity in the Atlantic, diverging from the trends observed during recent La Niña patterns, which correlated with more active Atlantic hurricane seasons.