After Skymet, Below Normal Monsoon Gets Flagged By National Weather Service As Well
Representational Image: AI-Skymet
Key Takeaways:
- Monsoon 2026 likely below normal: Skymet at 94% LPA vs 92% in other estimate
- Spatial and temporal distribution more critical than overall rainfall percentage
- July–August remain key months, especially for central and eastern India
- Multiple global factors like El Niño, IOD, and MJO make monsoon prediction complex
Skymet had issued its comprehensive southwest monsoon forecast for 2026 on 07 April 2026. Skymet expected the seasonal rainfall to be ‘below normal’ for the four-month-long season from June to September. Close on its heels, the National Weather Service has also announced the first estimates of monsoon rainfall for the country. The monsoon has been flagged ‘below normal’ for the 2026 season. The two forecasts, though similar, come with a difference of 2% in the quantum of rainfall. Skymet estimates it to be around 94% of the Long Period Average (LPA), whereas the figure stands at 92% in the other forecast. There is not much to read between the lines for this small variation in estimates. Model configurations, parametrization, and different sets of initial conditions are bound to leave some gaps in these two forecasts.
More than the percentage of rainfall, the spatial and temporal distribution is of greater concern. The shortfall of 6–8% of rainfall can be absorbed without much complication, provided the rainfall is equitable and timely. The core monsoon months of July and August always carry bigger stakes, more so for the core monsoon rainfed zones of central and eastern parts of the country. Due to persistent heat and possibly prolonged dry spells, stress on soil moisture increases, depleting the water table underneath.
El Niño is an ocean-atmosphere coupled phenomenon. It is repetitive in nature. However, appreciable changes in the characteristics of the event have been noticed over the last couple of decades. The frequency of both El Niño and La Niña has become irregular, outside earlier norms. The grey area during El Niño years is that the monsoon forecast is largely El Niño-centric. This binary approach is considered insufficient and inadequate. There is also no mention of the type of El Niño likely to develop through the season, which is a very important aspect that often gets sidelined.
Closer home, the IOD factor in the Indian Ocean is a very strong indicator for the monsoon. However, its limited lead time for accurate forecasting remains a predicament. A strong positive IOD can counter the ill effects of El Niño, as seen in 2019. The Madden-Julian Oscillation (MJO) is another important parameter. It is a key intra-seasonal tropical atmospheric disturbance that significantly modulates the Indian Monsoon in its active phase. Being a transiting parameter with a large cycle time of 40–60 days, it may visit only twice, and that too for a short duration, during the entire season to catalyse rainfall. Unpredictability remains quite high. The monsoon, by itself, is a huge synoptic-scale phenomenon. It has a tremendous amount of energy, which makes its internal dynamics rather complex. In the existing scenario and with available resources, decoding the monsoon will remain a great challenge and a complex puzzle to solve.
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