Red, orange and yellow alerts have been declared over Kerala, Karnataka, Tamil Nadu and Telangana for the next four days (until Saturday) in the run-up to the formation of a low-pressure area off the coast of Andhra Pradesh. The alerts are likely to be reviewed and revalidated post the formation and expected intensification of the system.
The 24 hours ending on Tuesday morning saw heavy to very heavy rainfall being reported from Lakshadweep, North Interior Karnataka, South Interior Karnataka and Kerala, apart from hills of West Bengal and Sikkim and Arunachal Pradesh, an India Meteorological Department (IMD) said.
Heavy rain fell over East Madhya Pradesh, East Gujarat, Odisha, Rayalaseema, Telangana, Coastal and South Interior Karnataka, Coastal Andhra Pradesh and Tamil Nadu.
‘Low’ to form by Saturday
The IMD is monitoring the skies over East-Central Bay of Bengal for signals for the formation of a parent cyclonic circulation by Wednesday, which will descend to the lower levels of the atmosphere to set up a low-pressure area by Saturday.
Numerical weather model projections indicate the strengthening of the ‘low’ during the day, following which it would cross the Andhra Pradesh coast to the accompaniment of heavy to very heavy rain over the coast.
Twin-system on west coast
This would also trigger heavy rain along the Odisha and West Bengal coasts as well as on the west coast where strong monsoon flows will converge around Goa to throw up a twin circulation. It is forecast to move up along the coast towards Mumbai and South Gujarat where it would blow up in a torrent of rainfall.
Meanwhile, the Bay system would have moved in over Central and West India across Chhattisgarh, Madhya Pradesh and Gujarat. A successor ‘low’ is predicted to materialise over the Bay during this phase, which along with the predecessor perched over Gujarat by then, are depicted holding two ends of a vigorously active monsoon trough across Central India.
Withdrawal to take time
The tit-for-tat action brewing in both the seas may not allow the monsoon withdrawal process to resume from the western-most outpost of Rajasthan-Gujarat at least until September 22, an updated outlook from the US National Centres for Environmental Prediction indicated.
Sentinel monsoon systems are forecast to keep their guard around the two hotspots off Saurashtra-Kutch on the west coast and the Head Bay of Bengal on the east coast. IMD’s projections tend to agree with these at least until September 17 when a rain-spewing weather system will keep the deserts of North-West Rajasthan in thrall.