Prepare for El Niño
Weather experts warn that the chance of an El Niño forming this year has tripled, while the Indian Ocean is also warming.
The Australian Bureau of Meteorology has officially changed its El Niño–Southern Oscillation (ENSO) outlook status to an El Niño warning.This comes while international weather forecasters say the chances are three times higher (or around 70%) that an El Niño will still form this year. El Niño conditions are associated with more unpredictable and often weaker rainfall in Namibia.
"The central and eastern surface temperatures of the Pacific have now warmed so much that they have reached El Niño thresholds. In addition, all weather models studied by the bureau predict that ocean temperatures will continue to rise and remain above El Niño thresholds - at least until spring in the Southern Hemisphere," the bureau announced in their latest climate update on Tuesday.
Before an El Niño weather phenomenon is officially announced, the above thresholds must be maintained for at least three months.
However, the bureau says some other climate indicators, such as the Southern Oscillation Index (SOI), also point to El Niño conditions. The SOI serves as a measure of the relationship between sea surface temperatures in the Niño areas and overhead weather systems.
"Yet, at the same time, winds, cloud formation and air pressure patterns that create specific conditions in the Pacific Ocean and the atmosphere do not yet indicate the formation of an El Niño."
In addition, it appears that the Indian Ocean Dipole (IOD) can reach positive values in winter, which means the sea surface temperature can become warmer than normal.
This is not good news for Namibia's rain prospects, especially when it is accompanied by an El Niño weather phenomenon.
The independent agricultural meteorologist, Johan van den Berg, previously explained that when the Indian Ocean's surface is warmer than normal and the IOD is positive, it forms strong low pressure systems or cyclones. "Then it rains a lot where cyclones form. Due to this, moisture that should have come down over Namibia, Botswana and South Africa is withdrawn over the Indian Ocean," he said.
This warning comes at the same time that satellite images point to critical drought conditions and below average vegetation in the ||Kharas, Omaheke, Oshana, Omusati and Zambezi regions as well as most parts of the Kunene and the western parts of the Hardap region.
According to the grazing specialist Dr Cornelis van der Waal, the latest survey of grazing conditions on 31 May, indicated that many of the above-mentioned areas' drought conditions continued throughout the rainy season or prevailed for long periods, which resulted in little grazing currently being available.
In contrast, the Khomas region, southern parts of the Oshikoto region and parts of the Kavango West region are greener than normal for the time of year.
However, Van der Waal said that vegetation productivity improved in many areas in Namibia during May compared to April.
"Still, vegetation growth in certain parts of the country is below average while the rainy season has now officially come to an end," he said.