Monsoon to break jinx over Karnataka, extend reach over West Coast

The monsoon has not progressed from Karwar, Chickamagaluru, Bengaluru and Dharmapuri where it reached a week ago, and has ran up a rainfall deficit of 26 per cent over parts of the South Peninsula after it arrived over Kerala on May 29. The deficits is in ‘large excess’ over Coastal Karnataka (-73 per cent) and Telangana (-68 per cent); ‘deficient’ over Kerala (-58 per cent); Coastal Andhra Pradesh (-34 per cent); and Lakshadweep (-26 per cent) as of June 9 (Thursday).

Mixed fortunes so far

But rain has been normal over South Interior Karnataka (14 per cent); North Interior Karnataka (8 per cent); Tamil Nadu and Puducherry (0 per cent); and Rayalaseema (-3 per cent) after the monsoon showed an unusual easterly bias for onward propagation this year (normally it pivots around the West Coast and inches its way to the North).

The ‘flawed’ progress is being attributed to the lack of either a supportive cyclonic circulation (onset vortex) over the Arabian Sea or the all-important offshore trough along the West Coast, a trademark monsoon feature. This has not allowed the usual convergence of monsoon flows to take place, which is evidenced in a burst of rainfall.

Monsoon left on its own

The core underlying reason why this has not materialised is the unforgiving attitude of the atmosphere above the Indian Ocean. It has not allowed a friendly Madden-Julian Oscillation (MJO) wave to travel from West to East over the Arabian Sea and the Bay of Bengal helping set up moisture and clouds.

There is no sign of the wave approaching Indian Ocean in the next two weeks either, per India Meteorological Department (IMD). This leaves the monsoon to power itself on its own dynamics, which is taking time, after a deep western disturbance travelling in the same direction over North/Central India stalled it progress from Sri Lanka.

May align better, strengthen

The moonsoon flows are forecast to align better and strenghen predominantly along Konkan and Goa over the next two days, as per an IMD outlook. The ongoing week (June 9-15) will see fairly widespread or widespread or light/moderate rain, thunderstorm and lightning over Karnataka, Kerala, Mahe and Lakshadweep. It will be scattered to fairly widespread over Andhra Pradesh, Tamil Nadu, Puducherry and Karaikal and Telangana during most days of the week.

Heavy rain forecast

Isolated heavy rainfall is forecast over South Interior Karnataka on Sunday; over Coastal Karnataka until Monday; and over Kerala on Saturday and Sunday. Fairly widespread to widespread rainfall with thunderstorms, lightning and gusty winds are likely over Konkan and Goa (including Mumbai) and scattered to fairly widespread with thunderstorm, lightning and gusty winds over Madhya Maharashtra and Marathwada during most days of the week. Isolated heavy rain is likely over Konkan and Goa on Friday and Monday and isolated very heavy on Saturday and Sunday.

Published on June 10, 2022