Monsoon likely to make landfall by May end in isles: Skymet

Report by: 
Port Blair
4 May 2018

The Andaman and Nicobar Islands may receive its first monsoon rains by the end of this month marking the advent of south west monsoon this year. Noida-based Skymet Weather, in its latest monsoon update, said that weather models indicate that south west monsoon 2018 is most likely to make timely onset over Kerala and official date for the onset of the four-month long season is June 1 with onset five days before or after being termed as normal. Southwest Monsoon reaches Andaman and Nicobar Islands 4-5 days before reaching the Indian mainland of Kerala
Skymet Weather has predicted normal Monsoon 2018 to the tune of 100% (with an error margin of +/- 5%) of LPA (long period average) of 887 mm from June 1 to September 30. “The monsoon are not steady winds and are rather pulsating in nature. Onset of Monsoon is always subject to fulfilment of meteorological conditions which include rainfall records at 14 specified locations, the wind field both in terms of speed and depth and outgoing longwave radiation (OLR). Although normal date of monsoon is June 1 but there has been early as well as delayed onset. To be precise, there has been huge variation in the onset dates. In last 47 years i.e. since 1971, there has been only three occasions when Monsoon had made onset on June 1 i.e in the years 1980, 2000 and 2013,” said Skymet.
As per the records, the earliest arrival of Monsoon was on May 18, 2004, while the latest arrival was on June 18, 1972. Out of 47 years, there has been 20 years when Monsoon arrived on June 1 or before wherein in 10 years saw Monsoon reaching even before May 26. However, onset of Monsoon has no relation with the progress as well as performance of Monsoon. Earliest arrival of Monsoon on May 18 of 2004 gave below normal rains to the tune of 86%, resulting in drought. Meanwhile, the delayed arrival of Monsoon on June 13 in 1983 gave excess rainfall to the tune of 113%, according to the agency.
Meanwhile, Skymet has forecast ENSO conditions to be neutral before monsoon. “Following the pattern of past several weeks, weak La Niña conditions continued to prevail as entire Pacific Ocean has been showing a warming trend. In the past one week, the sea surface temperatures (SSTs) have witnessed a significant rise. In fact, the Nino 3.4 index, which is primarily linked with the Indian Monsoon, has shown a substantial variation to the tune of 2°C. In fact, it is now seen at the value of 0°C on May 3 and is most likely to move towards the positive values in the coming week. Most of the weather models are indicating that the indexes would continue with the rising trend. In fact, there are strong indications that ENSO neutral conditions are likely to make way before the onset of Monsoon i.e. by May. These neutral conditions are most likely to continue throughout the Monsoon and hence, it would not have any adverse impact over the performance of Southwest Monsoon 2018,” according to