Dry days: On rainfall deficit forecast
An editorial analyses the India Meteorological Department's (IMD) April 2026 forecast of a below-normal southwest monsoon, and cautions against both undue alarm and complacency.
IMD's forecast projects the 2026 southwest monsoon at 92% of the Long Period Average (LPA) of 87 cm — approximately 80 cm — with a model error of ±5%.
El Niño conditions developing in the second half of the monsoon season (August–September) are identified as the primary driver of the expected deficit.
The editorial notes that historical El Niño years do not uniformly produce droughts — moderating factors such as the Indian Ocean Dipole (IOD) can compensate — and that India's improved irrigation coverage and drought-response systems reduce vulnerability compared to earlier decades.
However, the risk of food inflation, pressure on kharif crop output, and strain on water reservoirs are identified as legitimate concerns requiring proactive policy action.
IMD's Long-Range Forecasting and Probabilistic Methodology
The India Meteorological Department issues its Long Range Forecast (LRF) for the southwest monsoon in two stages — April (first stage) and May (second stage) — using ensemble climate models, Statistical Ensemble Forecasting System (SEFS), and the Coupled Forecast System Model (CFS).
Key Details
- The LPA is the benchmark: the average rainfall over a 50-year base period (currently 1971–2020). The LPA for the southwest monsoon is 87 cm.
- IMD expresses forecasts as a percentage of LPA with five categories: Excess (>110%), Above Normal (105–110%), Normal (96–104%), Below Normal (90–95%), and Deficient (<90%).
- The 2026 forecast (92% of LPA) falls in the "below normal" range, but the ±5% error range means it could slide to "deficient" (87% or less) or slightly into "normal" (97%).
- The probabilistic forecast assigns: 35% chance deficient, 31% below-normal, 34% normal-to-excess combined.
- Unlike a binary forecast, this probabilistic framing helps planners account for uncertainty in water resource management, agricultural advisory, and contingency planning.
The editorial's "no cause for alarm" framing is grounded in the wide confidence interval — the 34% chance of a normal-to-excess season is non-negligible, and the IMD's forecast track record shows that below-normal forecasts are often moderated by late-season recovery.
Water Security and Reservoir Management in India
India's major reservoirs (dams) serve multiple purposes — irrigation, drinking water supply, hydropower, and industrial use. Their levels at the onset of the monsoon determine the degree of "carry-over" from the previous year and the margin of safety for a deficit season.
Key Details
- The Central Water Commission (CWC) monitors 150 major reservoirs across India with a combined live storage capacity of approximately 178 Billion Cubic Metres (BCM).
- Reservoir levels at the end of May (pre-monsoon) are a leading indicator: if carry-over storage is high (from a good previous monsoon), a below-normal season is more manageable.
- The southwest monsoon contributes to approximately 80% of groundwater recharge in peninsular India.
- India's National Water Policy 2012 recognises water as a scarce and precious natural resource and calls for integrated water resource management across river basins.
- The Ken-Betwa Link Project and the National River Linking Programme (NRLP) are long-term strategies to redistribute surplus water from rain-rich basins to deficit ones — but their implementation remains partial.
A below-normal 2026 monsoon will stress reservoir levels, groundwater tables, and river flows — particularly in peninsular India (Deccan plateau, Karnataka, Tamil Nadu) which relies heavily on monsoon recharge for all-year water security.
Agricultural Adaptation and Drought Response Mechanisms
India's vulnerability to monsoon deficits has declined over decades through expansion of irrigation infrastructure, drought-resistant crop varieties, and stronger safety-net systems — though significant gaps remain, particularly for small and marginal farmers.
Key Details
- Irrigated area in India: approximately 68 million hectares (about 48% of net sown area); the remaining 52% is rainfed and fully exposed to monsoon variability.
- The Pradhan Mantri Fasal Bima Yojana (PMFBY), 2016, provides crop insurance against yield losses due to natural calamities including drought — but enrolment and claim settlement remain uneven.
- National Disaster Management Act, 2005, provides the framework for declaring drought and activating state-level relief; the National Crisis Management Committee coordinates at the centre.
- The ICAR (Indian Council of Agricultural Research) has developed drought-tolerant varieties of rice, wheat, and pulses under programmes like NICRA (National Innovations in Climate Resilient Agriculture).
- India's buffer stock norms for foodgrains allow the government to release grain into the PDS during supply shocks, dampening food inflation.
The editorial's calibrated tone reflects an improved institutional architecture for managing monsoon deficits — but the remaining 52% rainfed area and the concentrated risk in pulses and oilseeds (where rainfed dominance is near-total) still justify proactive preparation.
- 2026 IMD forecast: 92% of LPA (±5%); LPA = 87 cm (base period 1971–2020)
- Probability: 35% deficient, 31% below-normal, 34% normal-to-excess
- Southwest monsoon duration: June–September (four months)
- India's irrigated area: ~68 million hectares (~48% of net sown area)
- Rainfed area: ~72 million hectares (~52% of net sown area)
- CWC monitors 150 major reservoirs with ~178 BCM live storage capacity
- PMFBY (2016): India's main crop insurance scheme against drought losses
- NICRA: climate-resilient agriculture research programme by ICAR
- A 6% deficit rainfall in a recent monsoon season reduced agricultural growth to 1.4%