Long Range Forecast For the 2026 Southwest Monsoon Season Rainfall

1. At a Glance

• IMD's seasonal Long Range Forecast (LRF) for June–September 2026 projects all-India rainfall most likely below normal (90–95% of LPA), quantitatively 92% of LPA ± 5% model error [1].
• LPA reference period: 1971–2020 = 87 cm [1].
• Issued by the India Meteorological Department (IMD) under the Ministry of Earth Sciences (MoES); relevant for GS-I (geography), GS-III (agriculture, disaster mgmt., economy) [1][2].
• A below-normal forecast directly affects kharif sowing, reservoir storage, hydropower, rural wages and inflation — high-yield UPSC current-affairs hook.

2. Why in the News

• First-stage LRF released by IMD/MoES in April 2026 forecast below-normal monsoon — the first below-normal projection after two consecutive above-normal years (2024, 2025) [1].
• Updated (Stage-2) LRF released end-May 2026 retained the below-normal call and added regional/June outlooks [2].
• Drivers cited: transition from weak La Niña-like → ENSO-neutral, with MMCFS suggesting El Niño development during the season [1].

3. Background & Evolution

• IMD has issued operational LRFs since 1886 (Blanford); current statistical-cum-dynamical system since 2003, two-stage strategy formalised in 2007 [1].
• Monsoon Mission launched by MoES in 2012 to develop a dynamical prediction framework → produced the Monsoon Mission Climate Forecast System (MMCFS) based on a coupled global climate model [1][2].
• LPA baseline updated periodically; current baseline shifted to 1971–2020 (87 cm) from earlier 1961–2010 (88 cm) [1].
• Forecast is issued in two stages: Stage-1 (April) and Stage-2 (end-May) with monthly outlooks added thereafter [2].

4. Core Static Facts

• Forecasting agency: India Meteorological Department (IMD) [1].
• Parent ministry: Ministry of Earth Sciences (MoES) — not MoEFCC [1].
• 2026 quantitative forecast: 92% of LPA ± 5% [1].
• Probabilistic category: "Below Normal" (90–95% of LPA) [1].
• LPA (1971–2020): 87 cm for June–September all-India [1].
• Standard IMD rainfall categories: Deficient (<90%), Below Normal (90–95%), Normal (96–104%), Above Normal (105–110%), Excess (>110%) of LPA [1].
• Four homogeneous regions used in regional LRF: Northwest India, Central India, South Peninsula, Northeast India, plus Monsoon Core Zone (MCZ) [2].
• Models: Multi-Model Ensemble (MME) of coupled global climate models (CGCMs) + IMD's MMCFS dynamical system [2].
• Drivers monitored: ENSO (El Niño–Southern Oscillation, equatorial Pacific) and Indian Ocean Dipole (IOD) [1].
• June 2026 outlook: all-India rainfall <92% of LPA (below normal) [2].

5. Multi-Dimensional Analysis

Economic

• Below-normal monsoon threatens kharif output (rice, pulses, oilseeds, cotton) — kharif contributes ~50% of annual foodgrain output [1].
• Risks: food inflation spike, lower rural demand, reservoir stress for rabi irrigation [2].

Scientific / Technological

• MMCFS is India's first indigenous coupled dynamical model under the Monsoon Mission (MoES, 2012) [1].
• Stage-2 forecast uses April–May initial conditions + MME of CGCMs from multiple global centres for improved skill [2].
• Teleconnections used: ENSO (Niño 3.4 SST), IOD (Western–Eastern Indian Ocean SST gradient); weak La Niña → neutral → possible El Niño, with positive IOD likely later in the season [1][2].

Environmental / Climate

• Below-normal rainfall correlates with El Niño-onset years (historical: 2002, 2009, 2014, 2015, 2023) [1].
• Spatial inhomogeneity expected: NE, NW, and South Peninsula likely normal to above normal; much of central India below normal — implies drought-risk asymmetry [2].

Administrative / Governance

• LRF feeds into NDMA drought-preparedness, NITI Aayog rural advisories, Department of Agriculture & Farmers' Welfare contingency plans, and CWC reservoir management [1].
• States use LRF to trigger Crop Contingency Plans prepared by ICAR–CRIDA [1].

6. Recent Developments (last 12-18 months)

• April 2026: IMD/MoES Stage-1 LRF → 92% of LPA, below normal [1].
• End-May 2026: Stage-2 updated LRF retained below-normal call; added June 2026 outlook (<92% LPA) and four-region probabilistic forecast [2].
• 2025 monsoon (preceding year): forecast & realised above normal — context for 2026 reversal [1].
• Climate drivers (early 2026): weak La Niña-like Pacific conditions transitioning to ENSO-neutral; MMCFS flags El Niño emergence; IOD neutral with positive IOD likely later [1].

7. Prelims Hooks

• IMD's 2026 SW monsoon LRF: 92% of LPA ± 5% — "Below Normal" category [1].
• LPA baseline period: 1971–2020 = 87 cm [1].
• "Below Normal" band = 90–95% of LPA; "Normal" = 96–104% [1].
• Forecasting model: Monsoon Mission Climate Forecast System (MMCFS) [1].
• Nodal ministry: Ministry of Earth Sciences (not Agriculture, not MoEFCC) [1].
• Monsoon Mission launched by MoES in 2012 [1].
• IMD divides India into four homogeneous regions + Monsoon Core Zone for regional LRF [2].
• IOD = SST anomaly difference between Western (Arabian Sea) and Eastern (off Sumatra) tropical Indian Ocean [1].
• ENSO-neutral transition with potential El Niño flagged for SW monsoon 2026 [1].
• LRF issued in two stages: April and end-May [2].
• 2026 June outlook: below normal (<92% of LPA) [2].
• Positive IOD likely to develop towards end of SW monsoon 2026 [1].

8. Mains Relevance

• GS-I: Geography of India — Indian monsoon, factors influencing monsoon (ENSO, IOD, MJO).
• GS-III: Agriculture (cropping patterns, MSP, food security), Disaster Management (drought), Economy (inflation, rural distress), Science & Tech (indigenous climate modelling).
• Sample stems: 1. "Discuss how ENSO and IOD jointly modulate the Indian Southwest Monsoon. In light of IMD's 2026 LRF, evaluate India's drought-preparedness." (GS-I/III, 250 words) 2. "Examine the role of the Monsoon Mission and MMCFS in improving the skill of India's long-range monsoon forecasts." (GS-III, 150 words) 3. "A below-normal monsoon is a fiscal as much as a meteorological event. Discuss." (GS-III, 250 words)

9. Related Topics to Study Next

• ENSO (El Niño / La Niña) — primary teleconnection driving Indian rainfall variability.
• Indian Ocean Dipole (IOD) — secondary driver, often counteracts El Niño.
• Madden–Julian Oscillation (MJO) — intra-seasonal monsoon modulator.
• Monsoon Mission & MMCFS — flagship MoES R&D programme.
• PMFBY (Pradhan Mantri Fasal Bima Yojana) — risk transfer for monsoon failure.
• ICAR–CRIDA Crop Contingency Plans — operational drought response.
• Central Water Commission reservoir bulletins — water-security feedback loop.
• NDMA Drought Management Guidelines (2010) — institutional drought framework.

10. Common Errors / Trap Areas

• Wrong ministry: IMD is under MoES, not MoEFCC or Ministry of Agriculture.
• LPA value confusion: Current LPA is 87 cm (1971–2020) — older sources cite 88 cm (1961–2010); IMD revised the baseline.
• Category boundaries: "Below Normal" is 90–95% (a 5-point band); aspirants often confuse with "Deficient (<90%)".
• ENSO ≠ IOD: ENSO is Pacific; IOD is Indian Ocean — both independent indices.
• Forecast vs realisation: LRF is probabilistic; the 92% is a central estimate with ±5% model error — not a guaranteed deficit.
• 2025 vs 2026: 2025 was forecast/realised above normal; 2026 is the first below-normal year of the cycle — don't conflate.