IMD has issued seasonal monsoon forecasts since 4 June 1886. It missed the droughts of 2002, 2004 and 2009, then adopted a multi-model ensemble in 2021, cuttin…
IMD issued its first regular seasonal forecast on 4 June 1886. Blanford's rule: heavy Himalayan snow tends to mean a weaker monsoon.
Searching world data for monsoon predictors, Walker identified the Southern Oscillation, now known as the atmospheric half of El Niño.
A 16-parameter statistical model gave rainfall as a percentage of the Long Period Average, so every forecast could be checked.
Pacific warming after the April forecast suppressed the monsoon. No group in India or abroad saw it coming.
IMD forecast 96% in April and 93% in June. The season ended near 77%, as El Niño hit harder than its models expected.
IMD began combining many climate models, including its own MMCFS. Average error fell from 7.5% of LPA in 2017-20 to 2.28% in 2021-24.
An AI-enabled monsoon-advance forecast now covers 3,000+ sub-districts in 16 states, every Wednesday, up to four weeks ahead.
Yes. It forecast 92% in April and 90% in May. The season ended at 87%, the weakest since 2015, inside the forecast range.
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