La Nina is over
La Niña—the cool phase of the El Niño-Southern Oscillation (ENSO) climate pattern is over after three years. The definition of La Niña: the large-scale cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation (winds, pressure, and rainfall). The most recent weekly measurement of the sea surface temperature in the Niño was -0.2°C (-0.4˚ F) for January through early March. The cutoff for La Niña is cooler than -0.5 °C.
The word is—an El Niño may develop. This is the warm phase of the natural cycle called the El Niño Southern Oscillation (ENSO). We are “neutral” right now. The lack of El Niño or La Niña means that there is no seasonal-scale influence from the Pacific to push around the global currents and influence seasonal climate patterns.
The reason we care so much about El Niño and La Niña is that they can often be predicted months in advance, meaning we can get an early idea of some of our potential seasonal climate conditions. In the United States, La Niña can impact weather across the entire country. According to the National Oceanic and Atmospheric Administration (NOAA) website, “During the winter, La Niña typically brings above-average precipitation and colder-than-average temperatures along the northern tier of the U.S., along with below-average precipitation and above-average temperatures across the South.” La Niña is also typically associated with more active Atlantic hurricane seasons.
La Nina for us in the upper midwest doesn’t seem to be a huge factor. Usually colder weather for the winter and a bit wetter. For the southeastern US, it usually means warmer and drier.
