El Niño Is Already Active: U.S. Forecasts Strong and Prolonged Phase

The U.S. National Oceanic and Atmospheric Administration (NOAA) confirmed Thursday the formation of the El Niño phenomenon in the tropical Pacific, forecasting intensification from moderate to strong levels in the fall and a 63% probability that sea surface temperatures will exceed 2 degrees Celsius above normal in its impact area.

The Miami-based agency officially declared the beginning of the phenomenon after recording equatorial Pacific temperatures 0.5°C above average for several consecutive months, the threshold for formal declaration.

For the United States, the phenomenon implies drier conditions and a warmer-than-usual winter across most of the country, as well as an increase in storms in the south. NOAA also warned of increased risk of coastal flooding from swells on the West Coast, changes in fish migration routes, and greater formation of harmful algae blooms.

The announcement coincides with the early arrival of the summer's first heat wave, with temperatures exceeding 37°C across most of the country this week.

More cyclones in the Pacific, fewer hurricanes in the Atlantic

El Niño directly alters cyclone patterns in both oceans. In the Atlantic, the greater vertical wind shear generated by the phenomenon reduces the likelihood of hurricane formation: NOAA projected in May between 14 named storms and 6 hurricanes for the Atlantic season, below the historical average.

Cyclonic activity in the Pacific will be above average, with between 15 and 22 named storms forecast. NOAA had already warned in March that the drought affecting more than half of the United States would extend through this spring, with temperatures above the historical average across almost the entire territory from April to June.

Confirmation of a "very strong" and "prolonged" El Niño consolidates this scenario for the coming months and places 2026-2027 as a period of high climate impact in the hemisphere.