The low-pressure area over North-West Bay of Bengal (having moved in from the North-East Bay overnight on Monday morning) is expected to move west-northwestwards during the next 2-3 days and pass through East and Central India, an India Meteorological Department (IMD) update said.
In the process of doing so, it would intensify a round by Tuesday, setting off yet another spell of heavy to very heavy rainfall over East India and adjoining Central India and progressively into parts of North-West India, North-East India, the West Coast and the South Peninsula, the IMD added.
Extremely heavy rains seen
As for today (Monday), heavy to very heavy rainfall with extremely heavy falls is forecast over Coastal Karnataka; Odisha, Assam, Meghalaya, Konkan and Goa; heavy to very heavy over East Madhya Pradesh, Vidarbha, Chhattisgarh, plains of West Bengal, Arunachal Pradesh, Madhya Maharashtra, South Interior Karnataka and Kerala; and heavy over Jharkhand, hills of West Bengal, Sikkim, Nagaland, Manipur, Mizoram, and Tripura; Gujarat, Marathwada, Coastal Andhra Pradesh, Telangana, Rayalaseema, North Interior Karnataka and Tamil Nadu and Puducherry.
Strong winds (speeding to 45-55 km/hr) are likely along and off the Kerala-Karnataka coasts and Lakshadweep area while wind speeds may go up to 50-60 km/hr (strength of a depression) over North, South and adjoining Central Bay of Bengal. Fishermen are advised not to venture into these areas.
Monsoon withdrawal next week
The low-pressure area would likely encounter the monsoon withdrawal regime over Rajasthan and neighbourhood forcing it to beat a hasty retreat from South-West Uttar Pradesh and Delhi. It would be chased back along the foothills to Uttar Pradesh and Bihar before being pushed back into the Bay of Bengal.
This process is expected to pan out over a period from September 25 to 30, by which time the seasonal anticyclone that signals the withdrawal of the monsoon establishes over South-West Rajasthan and Gujarat. Jatin Singh, Managing Director of private forecaster Skymet Weather, says the monsoon withdrawal may commence next week and he sees pollution levels increasing by the third week of October.
Anticyclone to signal dry spell
The anticyclone, with winds blowing in a clockwise direction forcing the air to descend to the ground, does not allow clouds to build or precipitate and is a harbinger of a dry spell. This is the exact reverse case of a low-pressure area where the air is lifted up by winds rotating anti-clockwise, and cools to form clouds and rain.
Meanwhile, rainfall recorded for the country as a whole remains at 107 per cent of the long-period average, Jatin Singh observed. The season’s average rainfall of 880 mm has already been achieved ahead of time. Decent rains during this week may take it further to 108 or even 109 per cent for a second consecutive year, he added.