South Peninsula likely to witness thunderstorms till month-end

Many parts of the South Peninsula - including Kerala, Tamil Nadu and Karnataka – would receive thunderstorms, moderate to heavy rain, and squally weather - from this weekend even as strong incoming monsoon flows might throw up a rogue depression over the South-West Arabian Sea en route to Kerala.

India Meteorological Department (IMD) indicated that the depression may disrupt the monsoon flows and cause a part to head towards Yemen. But the IMD suggests that this would not be enough to prevent localised thunderstorms to invade the South Indian Peninsula farther to the East, as it waits the monsoon.

The IMD has already gone on record saying that the monsoon onset over the Kerala coast would be delayed by four days until June 5 (with a model error of four days) due to, among others, the overwhelming draining effect of erstwhile super cyclone Amphan over the subcontinent and the nearby seas.

Build-up off Sri Lanka

On Friday morning, Amphan’s pairing tropical storm, named Manggga over the South-East India Ocean, seemed to have emerged from the shadows of its much larger cousin, and come on its own while charting out a path to the south-east for a prospective landfall over western Australia in the next few days.

Meanwhile, Sri Lanka, the major port of call for the monsoon before it reaches Kerala along India’s south-west coast, is expecting the showery conditions over its south-west coast to enhance from today (Friday) due to developing low-level convergence in its vicinity. This is a good augury, given that the normal date for monsoon onset over the island nation falls today (May 22).

But the Sri Lankan Meteorological Department made mention of the monsoon apart from saying that showers or thundershowers will occur at several places over the western coast, Sabaragamuwa, the central and north-western provinces, and the Galle and Matara districts. Heavy falls of about 10 cm can be expected at some places. Wind speed can increase up to 50-60 km/hr at times.

Above-normal June rains

Six of the 11 Global Producing Centres affiliated to the World Meteorological Organisation and issuing long-range weather forecasts, have indicated above normal rainfall for Sri Lanka, and by extension to the South Peninsular India, during the month of June 2020. Only one model predicts below normal rainfall while the rest four do not indicate any specific signal. Accordingly, there is a possibility for having a slightly above normal rainfall for Sri Lanka during June.

The Myanmar Department of Meteorology and Hydrology said this morning that the South-West monsoon is weak over the Andaman Sea and the South-East Bay of Bengal after rampaging super typhoon Amphan robbed them much of the monsoon moisture and kinetic energy. The rest of the Bay is cloudy to partly cloudy. Amphan has dragged the monsoon into the South-East Bay almost five days ahead of schedule on May 18.

The Thailand Meteorological Department, which too monitors weather closely over the South-East Bay and Andaman Sea, said that the weather is cloudy with scattered thundershowers. From Krabi Island (Thailand) upwards, the south-westerly monsoon winds are clocking 15-35 km/hr while from Trang city (Krabi) downwards, the wind speeds are at 15-30 km/hr.