For third consecutive year, monsoon likely to be normal: Skymet

Monsoon is likely to be normal or above normal for the third consecutive year according to Skymet Weather, a private weather forecasting company. In its preliminary monsoon forecast for 2021, Skymet Weather said monsoon rain from June to September is likely to 103% of the long period average (LPA).

LPA is the long period average of 88cm based on average monsoon rain from 1961-2010.

In 2020 and 2019, monsoon was above normal at 110% and 109% of LPA respectively.

In its forecast on Tuesday, Skymet Weather said the northern plains, along with few parts of northeast region, are likely to be at risk of being rain deficient through the season. Also, interior parts of Karnataka could face scanty rains in the core monsoon months of July and August. “The onset month of June and the withdrawal phase of September is assuring good countrywide rainfall distribution,” Skymet Weather said in its statement.

According to Yogesh Patil, CEO, Skymet, “La Nina conditions have been prevailing in the Pacific Ocean since last year. It is however expected to remain neutral through the monsoon season. Occurrence of El Nino which normally corrupts the monsoon is ruled out.”

Indian Ocean Dipole (IOD) is neutral and is oscillating lightly on either side of zero line. Its unlikely to harm the monsoon season. El Niño and the Southern Oscillation (ENSO) is a periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific Ocean according to the National Oceanic and Atmospheric Administration (NOAA).

ENSO has a major influence on weather and climate patterns such as heavy rains, floods and drought. El Niño has a warming influence on global temperatures, while La Niña has the opposite effect. In India, for example, El Nino is associated with drought or weak monsoon while La Nina is associated with strong monsoon and above average rains and colder winters.

IOD is characterised by warmer sea surface temperature in the equatorial Indian Ocean; positive IOD conditions are usually associated with normal or above normal monsoon.

DS Pai, senior scientist, IMD Pune, had said in January that in a few years, India may be entering an epoch of above average monsoon rains. From 1945 to 1985 was also an above average rain epoch but from 1985 onwards, it has been a below average rain epoch.

“In a few years, we are likely to transition to an epoch of above average monsoon rains because monsoon follows epochs of around 31 years in these transitions. An above average epoch will be good for the country and agriculture but would mean more extreme rainfall events for which we should prepare,” M Mohapatra, director general, IMD, had said in January during a day long brainstorming session on monsoon forecast.