The onset date of the Southwest Monsoon over Kerala this year is expected on 07th June with an error margin of +/- 3 days. The onset will be delayed and the advancement slightly sluggish over Peninsular India. Hot weather will continue deep into June this year over central and northern parts of the country. This may not augur well for Kharif sowing.
A powerful cyclone 'FABIEN' is moving over the South Indian Ocean in the equatorial latitudes, abeam Southern Peninsula. The hurricane-strength weather system will take nearly one week to clear the area. This monster storm is restricting the cross-equatorial flow and the build-up of the Monsoon stream. Also, the Arabian Sea continues to host an anticyclone over the central parts in the lower levels of the atmosphere. This acts as a deterrent for the smooth streaming of Monsoon flow from the Arabian Sea to the West Coast. Other pertinent features are also not likely to get aligned with the desired wind pattern over the next 10 days or even more. There are no visible signs of establishing typical low-level jet (LLJ) of westerly winds, considered essential for the onset of Monsoon.
The mainland onset of Monsoon has a standard deviation of 7 days. In the last 10 years, the earliest arrival was on 29th May in 2018 & 2022 and the most delayed on 08th June 2019. The CFS-based weather models suggest strengthening of cross-equatorial flow and sea conditions supporting monsoon surge around 07th June 2023. A lag of +/- 3 days thereafter is quite normal for the commencement of weather activity along and off the Kerala-Karnataka coast.