In Skymet’s latest report about the transition from El Nino and La Nina, the private weather bureau said that it is difficult to predict the onset, intensity and duration of the ENSO cycle.
What is the ENSO Cycle?
The El Niño-Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean.
The vast ocean water bodies are warm or cool by anywhere from 1°C to 3°C, compared to normal. This directly affects rainfall distribution in the tropics. El Niño and La Niña are the extreme phases of the ENSO cycle; between these two phases is a third phase called ENSO-neutral.
Skymet said that global warming and climate change have altered the characteristics of El Nino and La Nina. And due to the ocean warming, a ‘cool’ La Nina year is now hotter than an El Nino year of 25-30 years ago.
Moving to specifics of this year’s Monsoon onset over India, Skymet said that the SouthWest Monsoon is likely to reach mainland Kerala on the scheduled date, though it is too early to comment on its further progress.
Skymet said two important aspects need pondering: La Nina is developing later than expected and IOD is likely to be weaker than the earlier forecast.
A positive IOD event is considered underway, once the IOD index is sustained above +0.4°C for about 8 weeks. It may be construed that the potential development of positive IOD has stalled, for the time being. The latest forecasts are suggesting a weaker IOD than earlier forecasts.
The weather bureau said in the report that the emergence of La Nina is certain, but the question is, when will it establish and how strong will it be. Also, how long will it last?
The National Oceanic and Atmospheric Administration (NOAA) has projected an 85% chance that the ENSO cycle will shift to neutral between April-June 2024, and then 60% chance, a La Nina will develop between June-August 2024.
