The European Centre for Medium-Range Weather (ECMWF) has dropped sufficient hints in its March-based long-range outlook about a likely blockbuster 2025 monsoon later for India this year.
India Meteorological Department (IMD) is expected to come out its first long-range monsoon forecast by mid-April. Weather watchers believe, with the tropical Pacific playing ‘neutral’ into the spring and later into the summer (meaning neither monsoon-friendly La Niña or monsoon-killer El Niño), localised climate drivers will decide monsoon performance.
Pre-monsoon rain
Early indications suggest West Coast (Konkan & Mumbai, Coastal Karnataka and Kerala) is bracing for heavy rain right from April-May-June, a trend that might carry on into the forth trimester of July-August-September. April-May-June covers pre-monsoon season, and will see heavy torrents lashing West Coast. Mumbai, Goa, Coastal Karnataka and Kerala are likely to be affected.
Some of the gains may flow out into western parts of Central India (West Madhya Pradesh, Marathwada and Madhya Maharashtra) and with slightly reduced intensity for Telangana. Rain-shadow Tamil Nadu is expected to receive normal rainfall.
Strong onset phase
May-June-July that coincides with onset of monsoon and its further propagation to Central India may likely witness proceedings gaining further urgency with heaviest of rainfall over Konkan & Goa, Coastal Karnataka and north Kerala while rest of West Coast continues to receive heavy rainfall. Heavy rainfall will spread out also into Central India and adjoining interior peninsula (Madhya Pradesh, Vidarbha, Chhattisgarh, Telangana) while Tamil Nadu may continue to receive normal rainfall.
Active Bay monsoon
May-June-July will also see Bay of Bengal arm of the monsoon coming into prominence, and aiding the spread of rainfall. This will continue into June-July-August with heavy rainfall regime covering Madhya Pradesh, Chhattisgarh and Odisha. By this time, the monsoon would have covered entire country, with heavy rainfall for South Gujarat and along the hills of North-West India (Jammu & Kashmir, Punjab, Himachal Pradesh and Uttarakhand), and above-normal rainfall for parts of Rajasthan.
Heavy rain to persist
June-July-August will see a similar rainfall footprint with heavy rainfall along West Coast, Central India and West India (including Gujarat and Saurashtra) and above-normal for Rajasthan and rest of North-West India except Uttar Pradesh, where it would be normal. The Bay of Bengal is seen sending out low-pressure areas to help rains cover entire north of the country.
July-August-September will be a near-replica of June-July-August scenario; only difference being heavier rainfall belt will confine itself to western, central and southern parts of country while East and North-East India will likely witness normal rainfall. A notable feature is at no phase across all four trimesters mentioned above is major deficit scenario being projected anywhere, least of all East and North-East India, which has been returning rainfall shortfall during past few years.