NEW DELHI, June 1 -- The southwest monsoon is expected to reach Kerala within the next two to three days, marking the start of a season critical to India's farm economy, even as the India Meteorological Department (IMD) forecast widespread thunderstorms and pockets of heavy rainfall across several regions this week.

The weather office said conditions remain favourable for the further advance of the southwest monsoon into parts of the southwest and southeast Arabian Sea, Lakshadweep Islands, parts of Kerala and Tamil Nadu, additional areas of the southwest, west-central, east-central and northeast Bay of Bengal, and the remaining parts of the southeast Bay of Bengal over the next two to three days.

The normal onset date of the southwest ...