NOAA said Thursday that El Niño now has an 81% chance of reaching very strong strength by October, a sharp rise from the 63% chance it assigned in June. The Climate Prediction Center also said there is a 97% chance the pattern will persist, keeping the Pacific setup in place as the Atlantic hurricane season moves toward its busiest stretch.
That matters now because Colorado State University lowered its Atlantic hurricane season forecast again on Wednesday, citing the high potential for a very strong El Niño during the peak of the season. Bryan Norcross said the forecast shift reflects a pattern that is already in motion, with a moderate El Niño present and a strong El Niño very likely to follow.
El Niño is one phase of ENSO, the climate cycle that tracks warmer-than-average water across the equatorial Pacific, colder-than-average water during La Niña, and near-average conditions when the pattern is neutral. NOAA’s latest outlook is not just a modest upgrade from June. The change from 63% to 81% means the odds of a very strong event increased by 18 percentage points, or nearly 29% relative to the earlier forecast, a sign that forecasters now see a more confident path toward a stronger event by fall.
The reason that matters for the Atlantic is straightforward. During El Niño, warmer water in the central and eastern Pacific Ocean shifts the subtropical jet stream, and that stronger jet typically reaches well into the Caribbean and Atlantic Ocean. Strong winds then make it harder for tropical systems to organize there, which is why El Niño is usually associated with fewer hurricanes in the Atlantic. But the same setup can tilt the balance the other way in the Pacific, where the deepest pool of warm water and lower wind shear can fuel major hurricanes and typhoons. The FOX Forecast Center has described that basin as a hyper-fueled engine under El Niño conditions.
The open question is not whether El Niño will matter, but how much. NOAA says the pattern is likely to persist through next spring, and that leaves the Atlantic hurricane season with less room to escape the impact if the event does reach very strong strength by October. Forecasters have a better read on the direction now than on the exact damage, and that is the number everyone will be watching next.
The shift also echoes earlier warnings that a stronger Pacific signal was building, including an El Niño forecast turn that had already pointed toward a more intense event. For Atlantic forecasters, the next checkpoint is whether the October odds hold, or rise again, as the season runs into its most vulnerable months.
