Monsoon flows over the Bay of Bengal and the South China Sea continued to be directed into tropical storm Mawar, a super typhoon till a couple of days ago in the North-West Pacific. The stubborn storm appeared to briefly stall the progress of the monsoon in upstream Bay yet again, an India Meteorological Department (IMD) update indicated.

A cyclonic circulation hung in the neighbourhood, over the North Andaman Sea and adjoining South Myanmar, and seemed ready to anchor the monsoon flows after the firm grip of Mawar ebbed over the following days. The Myanmar Department of Meteorology and Hydrology had earlier said the circulation may intensify as a low-pressure area, and grow in strength in subsequent stages.

Mawar effect on monsoon 

On Wednesday, global models suggested it would be until June 2 at least before these away-going flows cut themselves off from Mawar and allow some breather for the Bay and the Arabian Sea to get their act together to host the monsoon. Not surprisingly, the IMD said on Wednesday the monsoon will take as many days to make the next major lunge forward over these seas. 

The IMD said the monsoon may advance into parts of Maldives and the Comorin area; further over the South-West Bay; remaining South-East Bay; further over the Central Bay; and some parts of the North-East Bay during next 2-3 days. The Myanmar Met agency said the monsoon was ‘strong to vigorous’ over the Andaman Sea and the South Bay on Wednesday. 

MJO wave timeline

The US Climate Prediction Centre said a friendly Madden-Julian Oscillation (MJO) wave — a global band of low pressure, clouds and moisture traversing the upper atmosphere and overseeing the genesis of low-pressure areas, storm and even monsoon onsets on ground — may enter the Indian Ocean during June 14-20. But the monsoon may break over Kerala ahead of its arrival. 

Precisely why the CPC flagged the Arabian Sea and the Bay for potential to host a low-pressure area/depression around this time, with some models suggesting cyclone formation. What aims to lend credence to this is the forecast of enhanced cloudiness over the East-Central Arabian Sea during June 9-18, with a cloud mass pulling away from the West Coast towards Oman. 

ECMWF outlook till mid-June

The European Centre for Medium-Range Weather Forecasts (ECWMF) assessed the probability of total precipitation till mid-June (outlook for 10-15 days), crossing the 5-mm threshold at 100 per cent along Coastal Kerala and Karnataka, where the monsoon reaches first; 65 per cent along Goa-Konkan-Mumbai and adjoining narrow corridor of West Maharashtra and parts of Central-West Tamil Nadu, adjoining South Interior Karnataka and Rayalaseema. It is 5-35 per cent for the rest of the country. 

Volatile weather on 

Elsewhere over the mainland, a network of cyclonic circulation and troughs held sway on Wednesday and promised bouts of continued volatile pre-monsoon weather. A persisting western disturbance was parked over North Pakistan while an induced offspring cyclonic circulation lay over Punjab. A fresh western disturbance waited for its turn over North-East Afghanistan and neighbourhood. A cyclonic circulation each was perched near the monsoon gateways around Sri Lanka and East Bangladesh.