The South Asian Monsoon rainfall season is all set to make its first northward progression and onset over the Indian subcontinent and the neighbouring regions starting from the first week of June 2026. Latest available forecast guidance based on several global numerical weather prediction models indicate the likelihood of the beginning of the rainy season in a few days from now. Conditions are favourable for monsoon onset over Kerala between 3 and 5 June, and further progression along the west coast up to Konkan, parts of east and North East India to gradually set in during the first two weeks of June. Large scale environmental conditions and indicators of Monsoon rainfall including significant inter hemispheric pressure gradient, stronger upper level easterlies , strong low level westerlies, deeper moist column/moist adiabatic temp. profile etc., are all expected to establish during the first fortnight. Meanwhile, parts of northwest, west and adjoining central India can come under the influence of a southward digging deepening upper level trough in the subtropical westerlies. (Those rains not to be confused as Monsoon rainfall).
Scientific diagnostic reasoning:
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Large scale circulation analyses and forecasts on intraseasonal time scales suggest that the aforementioned monsoon's first northward progression is likely associated with an evolving equatorial wave mode that is expected to constructively interfere with the background climatological monsoon circulation as it propagates poleward. As it does so, the background conditions are also all expected to evolve quite quickly like the stronger reversal of meridional temp. gradient, northward receding of the upper level subtropical jet stream, intensification of the southern hemispheric Mascarene subtropical High, deepening heat low and the Monsoon Trough etc.,
