Scientists Watch El Niño's Effect on Weather and Hurricanes ^{CEFR B2}

Scientists are monitoring El Niño because it can alter weather patterns worldwide and influence the Atlantic hurricane season. El Niño means warmer-than-average sea surface temperatures in the central and eastern equatorial Pacific. That warming tends to increase upper-level vertical wind shear across the Atlantic, a factor that can tear apart developing tropical storms.

The European Centre for Medium-Range Weather Forecasts projects an increased chance for a strong El Niño this year. Emily Becker of the University of Miami says most climate models predict El Niño later this year and notes that subsurface tropical Pacific waters are currently warmer than normal, which is another indicator of a developing event. El Niño events usually occur every two to seven years and last nine to twelve months; La Niña is the cooler opposite. Becker estimates about an 80% chance of El Niño by fall and a one-in-four chance it will be strong.

Expected regional impacts include wetter winters for the Southeast U.S., cooler and wetter winters in the Southwest that could help drought, and more storms on the West Coast and across parts of the Pacific, which can bring flooding and landslides while the Pacific Northwest may be drier. The actual effect on the Atlantic hurricane season depends on timing and other factors. Ben Kirtman warns a late onset would have little effect on Atlantic wind shear, and very warm Atlantic sea surface temperatures can offset increased shear. The Madden-Julian Oscillation, an eastward-moving tropical disturbance that cycles every 30 to 60 days, can also raise or lower storm activity if its wet phase aligns with hurricane season.

Researchers note limits to using artificial intelligence for ENSO forecasting because there are only about 75 years of observed events, with roughly 25 El Niño and 25 La Niña cases. For now, forecasters rely on dynamical models and multi-model systems such as the North American Multi-Model Ensemble developed by Kirtman, which helps inform NOAA outlooks. Scientists will keep monitoring Pacific temperatures in the coming weeks, while residents say they will stay prepared.