Skymet, a private weather forecasting agency, said on Tuesday the southwest monsoon in 2021 that will start from June is expected to be normal or above normal for the third consecutive year.
In its preliminary monsoon forecast for 2021, Skymet Weather said monsoon rain from June to September is likely be 103 per cent of the long period average (LPA). In 2020 and 2019, the monsoon was above normal at 110% and 109% of LPA respectively. The last time India had three consecutive years of normal monsoon was between 1996 and 1998.
The LPA for June to September rainfall is estimated to 880.6 mm, meaning that if the forecast comes true, the actual rainfall in the country will be around 907 millimeters.
Month-wise monsoon in June across the country will be 106 percent of LPA, which will be 166.9 millimeters of rainfall. There are chances of 70 percent normal, 20 percent and 10 percent of above-normal rainfall in June.
The monsoon in July will be 97 percent of LPA, which will be 285.3 millimeters of rainfall. According to Skymet Weather, 75 % chances of normal, 10 % above normal, and 15 % below normal rainfall in July. Monsoon in August is expected to be 99 percent of LPA which will be 258.2 millimeters of rainfall across the country and monsoon in September is expected to the best at 116 percent of LPA which will be 170.2 mm of rainfall.
Skymet Weather said the northern plains, along with few parts of the 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,” it said.
According to 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 the Zero lines. 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.
Out of the 685 districts in the country, the monsoon was normal in almost 75 percent of them, while it was deficient and below normal in the remaining in 2020.