The International Research Institute (IRI) for Climate and Society at the University of Columbia has come out with more daring predictions on the Indian monsoon compared to those made public by India Meteorological Department (IMD) on Wednesday. The most glaring difference in perception relates to rainfall trends for northwest India. While the IMD was apologetic about the prospects for this region, the IRI predicts good rainfall here during the July-August-September and August-September-October quarters. This outlook is corroborated by the Frontier Research Centre for Global Change (FRCGC) of the Japan Agency for Marine-Earth Science and Technology (Jamstec). According to them, the La Nina and the concurrent negative phase of the Indian Ocean Dipole (IOD) will drive rain into northwest India this time round. DEFICIENT LAST TIME The northwest had deficient rainfall during the surplus monsoon last year primarily because the positive IOD has caused monsoon currents to dump their most heavy showers over central India and the west coast. An IOD event results from the differential heating of the seawaters of the southwest Indian Ocean and east equatorial Indian Ocean. When the warming anomaly is present over the southwest Indian Ocean, a positive IOD occurs. The negative IOD results from the cooling of this region and corresponding warming up of the east equatorial Indian Ocean, similar to what is happening now. IOD events have a more profound and immediate impact on the Indian monsoon than the prevailing El Nino/La Nina event in the far-away Pacific. MUTED ONSET According to the IRI, the onset phase of the monsoon will be rather muted, but would be conspicuously prominent later on the west coast, especially along the ghats in the Mumbai-Konkan stretch, during the May-June-July quarter. The next quarter (June-July-August) will see the monsoon engaging in top gear in central India, the southeast peninsula (Andhra Pradesh, parts of Tamil Nadu) and parts of north India. Northwest India will bear the brunt during July-August-September and August-September-October. Western India, north India and peninsular India (except extreme south) too will get good rainfall during July-August-September. FINAL PHASE During August-September-October, western and northwest India will come in again for a battering, along with parts of southeast peninsula. Summing up, the IRI said North India and the peninsula will witness heavy showers during the last two quarters. Meanwhile, heating of the landmass was apace in north and central India, with mercury crossing the 40s at many places on Friday.