After much speculation, El Nino is all set to finally make an appearance. According to Skymet Weather, there is a broad consensus among all the dynamical as well as statistical models that weak to moderate El Nino conditions would prevail from October 2018 to December 2018. " In fact, these conditions would persist during the winters of 2018-19, growing further strong," it said. The World Meteorological Organisation (WMO) in its statement has stated that there is a 70 per cent chance of development of a weak El Nino by November. The met department's El Nino-La Nina forecast had earlier indicated that El Nino conditions are prevailing over equatorial Pacific Ocean and it is likely to develop in the next couple of months.
As per IMD officials, El Nino during winter causes warm conditions over the Indian subcontinent and during summer, it leads to dry conditions and deficient monsoon. El Nino causes reversal in global wind direction, affecting rains across many parts of the world. According to Skymet Weather, almost 90 percent of all the weather models across the globe are predicting 85 percent to 90 percent probability of El Nino conditions during NDJ (November-December-January).
"El Nino is an abnormal warming of the surface waters in the eastern tropical Pacific Ocean in comparison to the western Pacific. This occurs every four to 12 years. As temperatures rise, rainfall patterns change around the world. Some places receive more rain, some get less. It is estimated that 60 percent of all droughts in India in the last 130 years have coincided with an El Nino. These have been years when rainfall was over 10 percent less than normal. This year, rainfall deficiency is recorded 9 percent. As many as 254 districts are faced with drought like situation in India. Even, rain deficiency is loom large during northeast monsoon which have been delayed to due cyclonic pressure 'Titli' over Bay of Bengal and Arabian sea," officials said.
IMD officials said that El Nino is a very complex phenomenon to explain and is quite famous for its notorious behavior. "Particularly for sub-tropical region that bears the maximum impact of these phenomena, invariably linked with below normal rainfall during the Southwest Monsoon," they said.
"Although April or May 2019 onwards, there are some indications of the El Nino tapering down, however, Monsoon 2019 in India may not be able to escape the impact of this oceanic phenomena," officials added.
Even in its devolving stage, it holds the power to corrupt the four-month long Monsoon season and sometimes leading to severe drought.
El Nino is famous for not behaving in similar pattern or same place every time it appears. There is no rule book for the same, keeping meteorologists on toes.
In a normal year, low atmospheric pressure develops over northern Australia and Indonesia, with high pressure over the Pacific. Consequently, winds over the Pacific move from east to west. The easterly flow of the trade winds carries warm surface waters westward bringing rainstorms to Indonesia and northern Australia. Along the coast of Peru and Ecuador, cold deep water wells up to the surface to replace the warm water that is pulled to the west.