Thursday's depression crossed the North Tamil Nadu and adjoining South Andhra Pradesh coasts between Puducherry and Chennai between 0300 hrs to 0400 hrs this (Friday) morning to the accompaniment of intermittent showers over Chennai but heavier rain into the interior.

The Chennai bloggers tweeted that the depression did not rain in Chennai as much as expected but drove most of the heavier rain into interior Tamil Nadu. India Meteorological Department (IMD) located the system about 60 km South-South-West of Chennai and 60 km North-North-East of Puducherry.

Heavy rain over Interior TN

The 24 hours ending 5.30 pm yesterday (Thursday) saw significant amounts of rainfall unfolding over Tamil Nadu, Puducherry and Karaikal (in cm) across Puducherry-15; Tirupattur-7; Vellore-6; Chennai and Dharmapuri-5 each; Tiruttani-4; Numgumbakkam-3; Tirupathi-9 and Arogyavaram-2.

The slow-moving system is expected to move West-North-West and weaken gradually into a well-marked low-pressure area later today (by evening/night on Friday). Satellite pictures this (Friday) morning showed rain clouds moving into Rayalaseema and adjoining North Interior Karnataka.

Clouds over Rayalaseema

The IMD has forecast light to moderate rainfall at most places with heavy to very heavy rainfall at isolated places over south coastal Andhra Pradesh, Rayalaseema and South Interior Karnataka and heavy over North Tamil Nadu, Puducherry, Telangana, Coastal and North Interior Karnataka. 

Squally wind with speeds reaching 45-55 km/hr gusting to 65 km/hr may prevail over South-West and adjoining West-Central Bay of Bengal and along and off the coasts of Tamil Nadu, Puducherry and adjoining South Andhra Pradesh coasts until noon on Friday and decrease gradually thereafter.

Arabian Sea 'low'

Meanwhile, the counterpart 'low' over East-Central Arabian Se is likely to move away from the West Coast of India and become more marked (intensify) in the next two days, the IMD said.

A trough extending from the 'low' over the East-Central Arabian Sea to South Madhya Pradesh across North Maharashtra helps it share the moisture feed from the warm seas with the Bay system over land.

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