COIMBATORE: Tamil Nadu Agricultural University (TNAU) has forecast near-normal rainfall in the northeast monsoon (NEM) season — from October to December end — in the state, at a 60% probability level. It has said the state is likely to receive about 468 mm of NEM rainfall, close to the long period average (LPA) of 464 mm. Among 38 districts in Tamil Nadu, 31 are projected to receive rainfall lower than their normal, while seven may see a slight increase in the range of 1–9%.TNAU’s district-level rainfall forecast, prepared using the Southern Oscillation Index (SOI) and Sea Surface Temperature (SST) conditions over the Pacific and Indian Oceans during July–August, was generated through the Australian Rainman International V.4.3 software.The outlook comes after the state recorded 254 mm of rainfall during the southwest monsoon (June–September) against a normal of 292 mm, marking a 13% deficit as on Sept 22.TNAU indicated that NEM could provide partial relief by improving soil moisture conditions, boosting reservoir storage and supporting groundwater recharge. However, the university cautioned that prevailing El Niño conditions could influence monsoon circulation and lead to uneven spatial and temporal distribution of rainfall. Coastal districts may face intense wet spells, particularly when cyclonic systems develop over the Bay of Bengal, while interior districts could experience more dry spells, especially in December.NEM contributes nearly half of Tamil Nadu’s annual rainfall and remains critical for agriculture and water management. Farmers have been advised to use weather forecasts and agro advisories for decisions on sowing, irrigation scheduling and fertiliser application, while closely monitoring cyclone and heavy rainfall alerts.For farm-level preparedness, TNAU recommended harvesting and storing excess rainwater in farm ponds during wet spells for use during dry periods. It advised mulching, random tie-ridging and conservation furrows for moisture conservation in rainfed tracts.Village-level medium-range forecasts are available at https://vlf.aastnau.in/ and https://vlf.aas.tnau.in/, while weather-based agro-advisories can be accessed through TNAU’s Automated Agromet Advisory app and portals https://aastnau.in and http://aas.tnau.ac.in.
