COIMBATORE: Tamil Nadu Agricultural University (TNAU) on Friday released a district‑level seasonal forecast indicating that the State is likely to receive a broadly normal Northeast Monsoon (NEM) this year, with estimated rainfall of 438 mm for October–December against a long‑period average of 434 mm.
Forecast basis and overall outlook
The forecast, prepared at a 60 per cent probability level, used recent climate indices including the Southern Oscillation Index (SOI) and Sea Surface Temperature (SST) values from the Pacific and Indian Oceans recorded during July and August. TNAU noted that prevailing El Niño conditions may influence circulation patterns and could cause spatial variability in rainfall across the State.
According to the university, the Southwest Monsoon (June–September) rainfall recorded up to 22 September stood at 254 mm, against a normal of 292 mm, a deficit of around 13 per cent. The upcoming NEM is expected to provide partial relief by improving soil moisture, reservoir storage and groundwater recharge.
District differences and coastal risk
TNAU highlighted that coastal districts could experience intense wet spells associated with cyclonic systems, while interior districts may have relatively longer dry spells, particularly in December. The forecast lists several districts that are likely to record rainfall near or above their normals, and some which may see modest deficits.
- Mayiladuthurai is expected to record the highest rainfall: 991 mm against a normal of 910 mm (about a 9% rise).
- Chengalpattu is forecast at 780 mm versus a normal of 720 mm.
- Nagapattinam is likely to receive 864 mm against 849 mm.
- Several western and interior districts such as Tiruppur and Erode show small shortfalls relative to normal.
| District | Forecast (mm) | Normal (mm) |
|---|---|---|
| Mayiladuthurai | 991 | 910 |
| Chengalpattu | 780 | 720 |
| Nagapattinam | 864 | 849 |
| Coimbatore | 367 | 366 |
| Nilgiris | 444 | 451 |
| Tiruppur | 306 | 328 |
| Erode | 304 | 314 |
Implications for agriculture and water resources
TNAU advised farmers to closely monitor district‑level weather bulletins and follow agro‑advisories when making choices on sowing, irrigation scheduling and fertiliser application. The university specifically urged agriculturalists to plan harvests and maximise rainwater harvesting where possible.
"Farmers should closely follow weather forecasts and agro‑advisories while making decisions on sowing, irrigation and fertiliser application," the forecast document said.
Seasonal normal or near‑normal rainfall is expected to bolster soil moisture and help refill reservoirs, but the forecast cautioned that distribution will not be uniform. Local administrations in low‑lying coastal taluks and those prone to cyclonic rainfall will need to maintain preparedness for short, intense spells that can cause flooding and damage standing crops.
Regional specifics and preparedness advice
In the western districts of the State, the university expects rainfall to be close to normal at best, with some districts showing small shortfalls. The Nilgiris, for instance, is forecast at 444 mm, marginally below the normal 451 mm. Coimbatore’s projected total of 367 mm is effectively on par with its normal of 366 mm.
For planners and farmers, TNAU’s guidance emphasises:
- Adapting sowing schedules to updated district forecasts;
- Using irrigation judiciously to stretch water during dry spells;
- Prioritising rainwater harvesting and on‑farm storage to capture episodic heavy rain.
Local agricultural extension officers, panchayats and district disaster management teams will need to interpret the forecast at finer scales to guide communities, particularly in coastal and flood‑prone areas.
The university’s forecast adds to national and regional seasonal assessments that factor oceanic and atmospheric indicators. Authorities across the State are now expected to align contingency planning, reservoir operations and advisories for farmers to the district‑level guidance issued by TNAU.
(Staff Reporter: Selvan Murugesan)
