Monsoon this year is likely to be "below normal" at 93 per cent of the Long Period Average (LPA) owing to developing El Nino in the Pacific Ocean, which poses higher risk for the eastern parts and a major portion of central part of the country being rain deficient, private weather forecaster Skymet said on Wednesday.
The average, or normal, rainfall in the country is defined between 96 and 104 per cent of a 50-year average for the entire four-month monsoon season, which is 887 mm.
Skymet said monsoon is going to have "a very sluggish start" and deficit rains are likely to spill into July.
However, the second half of the season would see better rainfall as August and September are expected to see normal rains, Skymet Managing Director Jatin Singh told reporters in New Delhi.
"The Pacific Ocean has become strongly warmer than average. The model projections call for 80 per cent chance of El Nino (weather-producing phenomena) during March-May, dropping to 60 per cent for June to August. This means, it is going to be a devolving El Nino year, though retaining threshold values all through the season. Thus, Monsoon 2019 is likely to be below normal," he said.
Once the El Nino tamps down, neutral conditions will set out, allowing improvement in rainfall, said Mahesh Palawat, Vice President (Meteorology and Climate Change) of Skymet.
"The saviour factor could be IOD (Indian Ocean Dipole) which is likely to be in the neutral or positive phase during the Monsoon. Thus, it may be able to absorb some of the El Nino blues and possibly would support rainfall during the second half of Monsoon," he said.
Among the areas that will be affected due to deficient rainfall are Karnataka, Vidarbha and Marathwada in Maharashtra, southwest Madhya Pradesh, Bihar, Jharkhand along with the northeastern states.
On the other hand, Chhattisgarh, Odisha, and coastal Andhra Pradesh will receive more rainfall, said GP Sharma, President (Meteorology and Climate Change) at Skymet.
Onset of monsoon can not be predicted at this moment and it has no relation with the overall rainfall the country receives, he said.
The rainfall in June will be 77 per cent (126 mm) of the LPA while it will be 91 per cent (263 mm) in July, 102 per cent (266 mm) in August and 99 per cent (171 mm) in September.
Palawat also said temperature in the national capital will be under control this summer due to pre-monsoon activities.