Southwest Monsoon 2023 irrefutably ended ‘below normal’. Four month long season, from June to September, recorded 94% rainfall of long period average. National Weather Service has unambiguously defined categorization of monsoon rainfall as Excess, Above Normal, Normal, Below Normal and Drought. Seasonal rainfall between 90% and 95% of long period average ( 868.6 mm) is categorized as ‘below normal’, without any further concessions. All weather agencies, including Skymet, have been diligently following these standards. Any compromise with these grades is considered, nothing short of blatant violation and misinterpretation of scientific data.
Off late, there has been fractured information appearing in the print media, that this was the eighth year in a row that monsoon rainfall in India was in the normal range. It was not so. In the last 8 years, since 2016, southwest monsoon rainfall was ‘normal’ ( 2016, 2021), ‘above normal’( 2019,2020, 2022) and ‘below normal’(2017, 2018, 2023). The obfuscated prefix and suffix like, ‘technically normal’ or ‘broadly normal’ are exactly forbidden in the scientific parlour.
United states national weather agency National Oceanic and Atmospheric Administration (NOAA) affirmed that a fifth of India is undergoing drought. Drought conditions were confirmed over northern, eastern and coastal southwestern parts of India on the ‘India Drought Monitor’. District level rainfall has been highly erratic. Kerala, one of the rainiest state, observed scanty rains and finished with a large deficit of 34% rainfall.
Long Period Average (LPA) of seasonal monsoon rainfall has been unjustifiably revised thrice in the last 5 years. The term LPA by itself is getting subsumed by such repeated emendations. Indian Summer Monsoon Rainfall (ISMR) LPA was 887.5mm till 2018. This was revised to 880.6mm in 2020. Another updation in 2022 reduced the margin of LPA to 868.6mm. Going by the LPA of 2018, the latest southwest monsoon 2023 would have had the scare of an imminent drought.
A poorer than normal monsoon was pre-empted this season. It its foreshadow, released on January 04, 2023, Skymet assessed the monsoon 2023 to be sub-par. This prediction was retained while releasing the comprehensive monsoon forecast on April 10, 2023. Skymet announced the upcoming monsoon to be ‘below normal’ to the tune of 94% of the long period average. This was a precision forecast unmatched by any other forecasting agency at the national level. Let us observe precepts and refrain from diluting statute.