The Bay of Bengal may pitch in another low-pressure area in an apparently unending procession of rain-generating systems criss-crossing the land.
This is even as the monsoon negotiates the second week of the fourth and last month of the season.
The European Centre for Medium-Range Weather Forecasts sees the ‘low’ latching on to the Andhra Pradesh coast by Sunday and initially moving straight west over the central and adjoining southern peninsula.
Andhra Pradesh, Telanagna, Karnataka, adjoining south and west Maharashtra, and Kerala are seen benefiting from its track of movement.
Later, it may get a move to west-northwest and slip out into the Arabian Sea from the Konkan-Goa coast by September 19 (Friday next).
International models indicate that the ‘low’ would likely have been transmitted from a westerly movement of a monsoon pulse in the South China Sea/west Pacific, which is witnessing action after a long interval during this season.
Action in Pacific
A ‘low’ had developed in the South China Sea and tracked west-to-northwest in an alignment ideal to trigger activity in the Bay of Bengal across IndoChina.
On the other hand, a typhoon named ‘Fengshen’ has developed in the West Pacific, and is racing away and in strength, tracking to the south of the Koreas and Japan.
The sudden activity has been triggered as an upper-level Madden-Julian Oscillation wave transited the Bay of Bengal during the week-end to enter these basins.
The Australian Bureau of Meteorology said that during much of August, the wave stalled over northern Indian Ocean including the Bay), fuelling tropical convection.
Peak monsoon
This triggered a significant increase in monsoonal rainfall over India, particularly over the past week, and ongoing still.
At the same time, much of August saw suppressed conditions over the southeast and northwest Pacific.
However, over the past week as the wave has moved into the Southeast Asian region, an increase in tropical activity has occurred. This has enhanced the Southeast Asian monsoon and also allowed for a typhoon to form near Japan.
Meanwhile, rain or thundershowers, though not heavy, may return to northwest India, including western parts of Jammu and Kashmir.
Rain for northwest
This will result as a prevailing ‘low’ over west Madhya Pradesh and east Rajasthan extends its influence while seeking to take a detour to the plains of northwest India.
The rain bands would find it easy to trigger thundershowers over a surcharged atmosphere in the region churned up like never before during the last week-end.
Passing western disturbances would only help further prime the air to set off rain or thundershowers along the hills and adjoining plains.
A trough connecting the ‘low’ passed through north Arabian Sea, south Gujarat, north Maharashtra, south Madhya Pradesh, south Chhattisgarh, and south Odisha.
This puts the entire south Gujarat, Mumbai and Konkan-Goa belt come face to face with a blast of southwesterly monsoon flows pulled in by the ‘low’ over the next couple of days.