The India Meteorological Department (IMD) announced on Wednesday that the Southwest Monsoon is expected to reach the Kerala coast by Thursday. Previously, the IMD had predicted the monsoon’s onset in Kerala for May 31, compared to this normal date of June 1, with a standard deviation of 7 days.
“Conditions are becoming increasingly favorable for the onset of the southwest monsoon over Kerala within the next 24 hours,” the IMD stated.
Kerala has been experiencing heavy rainfall for the past two weeks, resulting in a 39 percent surplus (465 mm) rainfall from March to May, with over 90 percent of this occurring in May.
This year, the Bay of Bengal branch of the monsoon is particularly strong, potentially leading to an early monsoon arrival in the Northeastern states. The usual onset date for these states — Arunachal Pradesh, Tripura, Nagaland, Meghalaya, Mizoram, Manipur and Assam — is June 5. If the monsoon arrives early, it could exacerbate the existing flood situation, landslides, and river overflow caused by Cyclone Remal. The remnants of the cyclone remain as a cyclonic circulation over the region.
Additionally, the monsoon is expected to advance into more areas of the Arabian Sea, the remaining areas of the Maldives, Comorin, Lakshadweep, the southwest Bay of Bengal, the northeast Bay of Bengal, and the Northeastern states.
The IMD uses specific ocean-atmospheric parameters to declare the monsoon onset over Kerala. The latest criteria, established in 2016, include the requirement that after May 10, the infall over 14 stations in Kerala and neighboring areas most exceed 2.5mm for two consecutive days, along with measurements of Outgoing Longwave Radiation (OLR) and the depth of westerly winds up to 600 hPa to indicate the strength of the monsoon winds. Once these criteria are met, the IMD officially declares the monsoon onset over Kerala.
Mrutyunjay Mohapatra, Director General of the IMD, mentioned earlier this week that the monsoon advancement over southern peninsular India is expected to be swift and timely.