Weather Academy: La Niña’s Effect on Hurricane Season

MONROE, La. (KNOE) - For the last few weeks, we have been talking about El Niño and La Niña climate patterns. Today I want to focus on La Niña and how it can affect hurricane season.

We’ve actually seen a La Niña pattern for the last two years and are entering our third year. Since La Niña first intensified in late summer 2020, the past two hurricane seasons have generated 51 total storms, 21 of which became hurricanes and 19 of which made landfall in the united states. And 2022 looks to be another La Niña year which could lead to another above-average season as NOAA is predicting anywhere from 14 to 21 named storms and 6 to 10 hurricanes.

But why do la Niña years lead to more hurricanes? Last week Sheena taught us that during a La Niña pattern, the trade winds will be strong out of the east taking warm water in the Pacific towards Asia, and leaving behind cold water off the coast of South America. Cool conditions at the surface of the sea can have a big impact on what’s happening in the upper levels of the atmosphere. This will eventually lead to a large trough out in the Pacific. That will mean less storms and more wind shear. But if we have a trough, we have to have a ridge somewhere. Our ridge will then set up off in the Caribbean Sea. This means lower wind shear in our region of the Atlantic basin which will eventually lead to more storms.

If we think back to what we know about hurricanes, the three main ingredients that we need in order to see tropical formation are warm surface temperatures of the ocean at or above 79 degrees, weak winds shear with high pressure aloft, and open ocean. La Niña helps to create the perfect environment for tropical development to occur. This will definitely be something to watch as we head into the rest of hurricane season.

Thank you for joining me on this morning’s Weather Academy. Be sure to tune in next we as we talk about the reason for seasons.

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