El Niño and record ocean heat complicate hurricane forecasts

The Atlantic hurricane season is currently underway, officially kicking off at the beginning of June, and a rocky forecast is expected as an atypical pattern develops in the coming months. This year has already been unusual, with two named storms forming concurrently in the Atlantic in June for the first time ever. Conflicting atmospheric features are convoluting the forecast ahead, as a combination of El Niño conditions and warm ocean waters work against one another.

The impacts of ocean temperatures on the hurricane forecast are fairly well-known, with warmer ocean waters usually associated with a higher frequency of stronger tropical systems. Sea surface temperatures in the Atlantic are currently at the highest levels ever recorded by a large margin, bringing great confidence in fuel for more tropical storms.

However, the long-term effects of El Niño have been observed unusually early in the year, with wind shear increasing across parts of the Atlantic Basin. Shear is a change in wind direction and speed with height, and this works against developing tropical systems.

While shear could diminish some activity in the season ahead, the magnitude of record heat is expected to win out. The newest tropical forecasts are now indicating above-average numbers of storms for the hurricane season as a result.