New Delhi: The southwest monsoon has arrived on the coast of Kerala on schedule, and rainfall across the country is likely to be normal this year, the India Meteorological Department (IMD) said Monday.
Presenting the long-range forecast of monsoon rainfall between June and September, M. Rajeevan, Secretary of the Ministry of Earth Sciences, said in a press briefing that the rainfall this season is likely to be 102 per cent of the long period average (LPA). The LPA over the country as a whole between 1961 and 2010 was 88 cm.
However, the Northeast will receive 96 per cent of the LPA, Rajeevan said, adding that the area has been consistently receiving less-than-average rainfall over the last few years.
The rainfall in the north-west region will be 107 per cent of the LPA, about 103 per cent in central India, while in the southern peninsula, it will be 102 per cent of the LPA.
Rajeevan also added that the probability of above-normal rains (LPA 100-110) is 25 per cent, while for excessive rain, it is 14 per cent. He also said that there is just 5 per cent probability of a deficient monsoon.
Last year, the IMD had predicted a normal June-September monsoon three times — on 15 April, 31 May and 1 August — with rainfall expected to be 96 per cent of the LPA.
Instead, the monsoon season saw excess rainfall of 110 per cent of the LPA, the highest in the country as a whole since 1994, which caused floods in major cities such as Patna.
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Revised dates for onset and withdrawal
This year, the IMD has revised the dates for monsoon onset and withdrawal, to account for changing climate patterns.
In an earlier press briefing, Rajeevan had said that while the onset date will remain the same for Kerala (1 June), it will get delayed by 3-7 days as the monsoon progresses deeper into the country.
In the Northeast, the monsoon are expected to arrive a little earlier — 8 July instead of 16 July.
The withdrawal of the monsoon is expected to be delayed by around 7-14 days over north-western India. However, the overall withdrawal date for the country remains the same, 15 October.
How IMD forecasts weather
IMD forecasts are prepared using the Statistical Ensemble Forecasting System (SEFS), which is reviewed and improved regularly through in-house research activities.
Since 2012, the IMD has also been using the dynamical global climate forecasting system (CFS) model, developed under the Monsoon Mission to generate experimental forecasts.
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