La Niña expected to continue
Elvira HattinghMeteorologists believe a third consecutive La Niña could occur during the 2022-23 rainy season.
“Although it is still too early to say for sure, it does mean that an El Niño is unlikely to make its appearance - and that is important,” the non-governmental organization LandWater said on Monday.
LandWater then also shared graphs from the US National Oceanic and Atmospheric Administration (NOAA), showing that La Niña conditions are still present and backed by the atmosphere.
LandWater says La Niña conditions are one of the main drivers of the abundant rains over Southern Africa, as well as “the ‘sports’ that are still on the way for the rest of April and possibly May”.
LandWater says the season is now in the midst of an interesting phase of the current rainy season.
It was explained that La Niña, which means “little girl”, comes with colder sea surface temperatures in the Pacific Ocean and is mostly “good” for Southern Africa. In contrast, El Niño, which means “boy”, is mostly “bad” for Southern Africa's rain prospects and is associated with warmer sea surface temperatures in the Pacific Ocean.
The Australian Bureau of Meteorology agrees that the current La Niña is still active but is expected to return to neutral levels soon.
“Climate prospects continue to indicate that neutral Enso conditions - neither a La Niña nor an El Niño - should intervene in the late summer or early winter of the Southern Hemisphere.” This is according to the bureau's forecast of 12 April.
Enso refers to El Niño Southern Oscillation climate pattern.
“Even while La Niña is weakening, it will still retain its influence on global weather patterns. This includes improving the chances of an above-average rainy season in Southern Africa. Enso indicators in the atmosphere and remain at La Niña levels. Sea surface temperatures are still cooler than normal at the equator. Compared to two weeks ago, the water has cooled down a bit more in the eastern part of the Pacific Ocean in the vicinity of the equator.
“Trade winds are stronger than normal across the western Pacific, while the Southern Oscillation Index (SOI) is less positive.”
The SOI is a measure of the relationship between sea surface temperatures and overhead weather systems and an indicator of La Niña conditions. When it is in a positive phase, it indicates that La Niña conditions prevail, while a negative phase would indicate an El Niño.
The Indian Ocean Dipole (IOD) is currently in a neutral phase. However, it usually has a small effect on global climate patterns between December and April. - [email protected]