India’s weather office on Friday reiterated its April forecast of a normal south-west monsoon, predicting 96% of the 50-year long-term average (LPA) rainfall of 89cm.
The south-west monsoon is expected to hit Kerala on 6 June, with a model error of +/-4 days, the India Meteorological Department (IMD) had earlier said. The typical date of arrival of the summer monsoon is 1 June, with a standard deviation of seven days.
The delayed onset of rains comes amid weak El Niño conditions in the Pacific Ocean, leading to apprehensions that the phenomenon could mar prospects of a good monsoon in the first two months.
“The weak El Niño conditions over Pacific are likely to continue during the monsoon with some possibility of these conditions to turn to neutral ENSO (El Niño–Southern Oscillation) conditions in the latter part of the monsoon season," IMD said in its second long-range forecast issued on Friday.
IMD said rainfall during July could be 95% of LPA and then increase to 99% of LPA during August, as weak El Niño conditions begin to subside. The monthly predictions have a model error of +/-9%. IMD said the average rainfall in June-September is likely to be 96% of the LPA, with a model error of +/-4%. In its first long-range forecast, too, the weather office had put the projection at 96% of LPA (+/-5%).
The Monsoon Mission Coupled Forecasting System (MMCFS) consisting of the coupled dynamical model, however, projects rainfall to be a little higher at 97%, with a model error of +/- 4% of LPA.
A normal monsoon will be a respite for farmers. Last year, IMD predicted rainfall at 97% of LPA; however, it ended at 91%, with a deficit of 9.4%. Rainfall is termed normal when the quantum of rain is 96-104% of LPA.
Millions of Indians depend on rains for agriculture, making the monsoon season crucial for India’s economy. It provides over 75% of rainfall to the country and irrigates over half its farms. However, the situation does not look promising for north-western states, which could witness below-normal rains at 94% of LPA.
Central India, which is the core monsoon region, could see rainfall at 100% of LPA. Seasonal rainfall over the southern peninsula may be 97% of LPA.
North-eastern states that faced a major rainfall deficit last year may face a similar situation this year, as rains in the region are likely to be at 91% of LPA.
All region-wise forecasts have a model error of +/- 8%.
The weather department will issue the next forecast at the end of July, after the monsoon covers the entire country.