Monsoon cheer: IMD forecast of well-distributed rainfall is a big relief

The forecast by the India Meteorological Department (IMD) that rainfall in this year’s monsoon season (June to September) is likely to be normal is in line with the outlook of other global and local weather agencies. While the IMD has projected total rainfall in 2018 to be 97 per cent of the long-period average (LPA) of 89 cm, private weather watcher Skymet has put it at an even more optimistic 100 per cent of the LPA. If these prognoses hold true, this will be the third consecutive normal monsoon after the back-to-back droughts of 2014 and 2015. However, more important than the total quantum of rainfall is its spread over time and space. Fortunately, the IMD has provided some reassuring indications on this count as well by pointing out that rainfall could be evenly distributed.

Copious and well-spaced precipitation is badly needed this year for several pressing reasons. For one, there has hardly been any winter rainfall in most parts of the country. Going by the IMD data, 404 districts (of the 588 evaluated) seem set to face a severe water crisis in the coming months. About 140 of these districts are categorised as extremely dry because of a lack of rain since the end of the previous monsoon season. Besides, the water stock in the country’s 91 major reservoirs has plunged 16 per cent below last year’s corresponding level and is currently about 10 per cent short of normal. To add to the country’s woes, the IMD foresees this year’s summer being warmer than normal in most regions. This is bound to exacerbate the water crunch. This aside, a benevolent monsoon is imperative for bolstering the beleaguered rural economy and mitigating farmers’ distress. The monsoon delivers about 70 per cent of India’s annual rainfall and determines the yield of key crops such as rice, wheat, sugarcane and oilseeds such as soybeans. It is needed also to boost rural demand for goods and services to prop up an economy that seems to be on the cusp of recovery. Replenishment of water resources, both surface and underground, on the other hand, is critical to meeting the requirements of agriculture, industry and hydel power generation.

Thankfully, the IMD’s weather prediction capabilities are gradually improving with the expansion of data gathering infrastructure and induction of better computation facilities. Its short- to medium-term forecasts have begun to prove fairly accurate though the same cannot be said as yet about its long-range monsoon forecasts. In the last five years, the IMD’s mid-April predictions have come close to reality only once. Last year, the actual rainfall was 95 per cent while the IMD had projected it at 96 per cent. But even then it had erred in correctly visualising rainfall in the second half of the season. This year, too, doubts arise about the monsoon because La Nina — deemed favourable for the monsoon — is reckoned will fade away before the monsoon’s arrival and the Indian Ocean Dipole, another sea temperature-related factor, is expected to turn negative during the middle of the monsoon season. The IMD is keeping a close watch on these developments, which can make or mar the monsoon’s performance.