Monsoon onset over Kerala likely on May 28: Skymet

The private weather forecaster Skymet Weather Services has predicted the onset of Southwest Monsoon over Kerala on May 28 with an error margin of plus or minus two days.

It said that a powerful system in the Bay of Bengal has been pushing the monsoon current, and the conditions are poised for an early onset over the Andaman Sea around May 16 or 17.

The likely storm in the Bay of Bengal will take about five days to wind down its impact from the region. Drained seas across the coastline on either side will take a few days’ time to rejuvenate. Possibly there could be a lull in the weather activity across most parts of Peninsular India for a few days, it said.

However, it said that the Southwest Monsoon onset over Kerala is announced on the fulfillment of specified conditions both over the ocean and overland. The wind direction, speed, and depth of westerly winds along with the quantum of outgoing longwave radiations (OLR) over the Indian Ocean in the proximity of the Comorin region are the decisive factors.

Of course, the rainfall amount for two consecutive days at 14 named stations of Karnataka and Kerala remains the most important and primary requirement, it said.

The usual onset date of Southwest Monsoon over Kerala remains is June 1. The monsoon onset has a standard deviation of seven days. That means on 99 per cent of the occasions the event occurs between May 15 and June 8.

It said that the earliest arrival in the last 10 years was on May 23 in 2009, and the most delayed was on June 8 in 2016. However, the weather models indicate a strengthening of cross-equatorial flow and the sea conditions supporting a fresh surge around May 25. A lag of two-three days thereafter is quite normal for the commencement of weather activity along and off the Kerala-Karnataka coast.

According to Skymet, the onset date over Kerala has no bearing on its further advancement to reach various parts of the country.