The offshore trough along the South Gujarat-North Kerala coast, a major indicator of the strength of the monsoon, weakened on Tuesday but India Meteorological Department (IMD) signalled formation of a fresh low-pressure area over the Bay of Bengal in the next two to three days (by Thursday).
It may, however, not cross into land at least until the middle of next week, as per the current outlook. The ‘low’ is expected to wax and wane in tandem with the dynamics of tropical storm Yagi in the North-West Pacific. On Tuesday, Yagi was heading in a monsoon-friendly west-north-west track and may intensify as a powerful typhoon. Global models suggest it may hit Taiwan, adjoining South-West China and Vietnam in multiple landfalls starting Friday.
Brewing Pacific typhoon
The ‘low’ in the Bay, embedded in the same monsoonal flows, will enter the West Bengal coast after Yagi crosses the South-West China coast and its remnant pushes into Vietnam and Myanmar and further into the Bay. It may merge with the ‘low’, and the combined entity may push toward the West Bengal coast by September 12.
The interregnum may see a high-pressure area with sinking motion of air developing over North-West India, weakening the monsoon in the region. A high-pressure area is a region of suppressed rainfall. It will be left to the Bay ‘low’ to push westward into Central India and hold back the high pressure area from growing in size and extent, a tall order from the look of it on Tuesday.
Isolated heavy rain forecast
The 24 hours ending on Tuesday morning saw heavy to very heavy rain with isolated extremely heavy falls recorded over parts of Gujarat Region (North Gujarat, Gandhinagar and South Gujarat) and heavy to very heavy rain over parts of West Madhya Pradesh, Konkan and Goa, Madhya Maharashtra and Coastal Karnataka. It was heavy over Punjab, Vidarbha, Odisha, North-East India, Marathwada, Telangana, East Rajasthan, South Interior Karnataka, Himachal Pradesh and Jammu-Kashmir.
Isolated heavy rain is very likely in West India across Konkan and Goa, and Gujarat Region during the next seven days; West Madhya Pradesh and Saurashtra and Kutch until Saturday; East Madhya Pradesh on Wednesday and Thursday; Vidarbha on Thursday; Chhattisgarh from Wednesday to Monday; and the ghat areas of Madhya Maharashtra for four days from Friday. It will be fairly widespread to widespread over the South Peninsula, East and North-East India and North-West India.