Bengaluru: After being battered by an unprecedented drought on record during the southwest monsoon this year due to strong El Niño conditions, Karnataka could get some much-needed respite in the form of the northeast monsoon, with meteorologists expecting near-normal rain over south interior Karnataka and coastal districts. The likelihood of normal rain is linked to the prevailing near-neutral Indian Ocean Dipole (IOD)—a key ocean-atmosphere phenomenon influencing rainfall patterns over the region.Meteorologists tracking IOD said it is currently neutral but showing signs of developing into a positive IOD. “Throughout the southwest monsoon season, IOD remained neutral. However, several international climate models and meteorological forecasts have indicated a transition towards positive IOD conditions over the next few weeks,” explained a senior scientist at IMD, Bengaluru.Weather experts said a positive IOD phase generally favours moisture convergence over the peninsular region and could aid the northeast monsoon from Oct to Dec. “If you look at the climatological history, strong IOD conditions can help offset the hot and dry conditions associated with El Niño and bring in late-season rain,” the IMD scientist said.Referring to IOD as the ‘Indian Niño’, the scientist explained that it is essentially the difference in sea-surface temperatures between the western Indian Ocean, including the waters off East Africa and the Arabian Sea, and the eastern tropical Indian Ocean near Indonesia. “During a positive IOD phase, sea-surface temperatures on the southeast Asian side become cooler, while temperatures in the Arabian Sea region become warmer. These conditions influence atmospheric circulation patterns and bring more moisture towards the peninsular region, resulting in enhanced rain,” explained CS Patil, scientist at IMD Bengaluru.According to IMD scientists who have been tracking IOD since the beginning of 2026, the index remained positive during the pre-monsoon season from Feb to April. A neutral IOD with a slight positive tilt during the northeast monsoon season could support near-normal rain, they said.IOD assumes significance for Karnataka, which has been grappling with drought and mounting pressure on its water and power resources. A normal northeast monsoon could bring additional inflows into reservoirs in Cauvery basin, easing the state’s growing water stress. However, the IOD signal by itself does not provide a specific rainfall prediction for Karnataka, and the eventual impact will depend on the evolution of regional weather systems, IMD scientists cautioned.Brace for showers this weekAmid the hope of a favourable northeast monsoon, IMD has forecast thundershowers over coastal and south interior Karnataka this week. “An active weather system is developing over parts of Karnataka and is likely to bring intense thundershowers, accompanied by strong gusty winds and fairly widespread rain across coastal and south interior Karnataka, including Bengaluru, throughout this week,” the IMD Bengaluru forecast said.
