IMD announced the onset of SWM 2026 over Kerala yesterday. The normal date for onset is 1st June with a +/- 7 days variance effectively making this year as a normal onset year. The presence of two circulations either side of Peninsular India has brought a classic onset conditions for Monsoon. The cyclonic circulation off the Peninsular West Coast may climb up slightly along the coast dragging onset along with it. Parts of Karnataka, Goa and South Konkan Maharashtra may benefit from this movement seeing SWM 2026 to check in.
The progress of monsoon has not been free flowing so far this year. It appears similar story may continue after monsoon onset over the mainland as well. Looking at the sub seasonal weather charts we could potentially see a stall scenario just as monsoon marked its presence. Over the next week to 10 days southern parts of Peninsular India up to South Konkan may benefit from monsoon conditions. Progress beyond south Konkan is likely to be slow. The risk of Monsoon not reaching Mumbai during this phase of onset remains high. If Mumbai misses its traditional onset date of 10th June then there is a very high chance SWM 2026 will hit the megapolis only during the 2nd fortnight of June.
Similarly we could also see slow progress from the Bay branch as well. Northeast states may see monsoon onset in the upcoming days. But progress into Gangetic plains may be delayed in the absence of large scale favourable atmospheric conditions. MJO, currently seen over Pacific, is likely to bring suppressed conditions over Indian Ocean and maritime continent until 2nd fortnight of June.
But there is fair consensus among models southern parts of Peninsular India may benefit from this slow movement. Which could potentially bring widespread rains all the way from Goa to Kanyakumari district in South TN. We may have to keep a close watch on the monsoon winds to see if the rains push into the Ghats as well. This is essential for catchment of rivers like Cauvery, Krishna etc. There could be some weakening of monsoon dynamics as we head to middle of June.