NOAA predicts a 55% chance of below-normal Atlantic hurricane activity, largely due to El Nino.
NOAA predicts a 55% chance of below-normal Atlantic hurricane activity, 35% chance of near-normal, and 10% chance of above-normal, largely due to El Nino.
El Nino Mechanism
El Nino is the periodic warming of surface sea temperatures in the central and eastern tropical Pacific Ocean. It weakens or reverses trade winds, allowing warm water to surge east toward the Americas. This shift suppresses Atlantic hurricane development while increasing Pacific storm activity.
Impact on Storm Formation
- North Atlantic: Historically, El Nino reduces hurricane days by 60% and overall system intensity.
- Northeast Pacific (near Hawaii): More storms form during El Nino.
- Australia and South Pacific: Fewer storms form off Australia; formation shifts east toward the international dateline.
- Northwest Pacific: Overall typhoon numbers remain similar, but fewer form near Asia and more form east toward the dateline.
- Southwestern and northern Indian Oceans: No major changes observed.
Background: Tropical Storms
Tropical storms form over warm ocean waters near the equator when warm air rises, creating low pressure. As winds reach 63 km/h (39 mph), it becomes a tropical storm; at 119 km/h (74 mph), it is classified as a hurricane, cyclone, or typhoon depending on location.
- Hurricanes: North Atlantic and Northeast Pacific.
- Cyclones: South Pacific and Indian Ocean.
- Typhoons: Northwest Pacific.
Naming
Storms are named using rotating lists managed by the World Meteorological Organization. Names are retired if a storm is particularly deadly or destructive.
Expert Statement
NOAA National Weather Service Director Ken Graham said, "Although El Nino's impact in the Atlantic Basin can often suppress hurricane development, there is still uncertainty in how each season will unfold. It only takes one storm to make for a very bad season. "