The Met department forecast heavy to very heavy showers in north coastal Tamil Nadu till tomorrow.
It said yesterday's low pressure area over Sri Lanka and adjoining south West Bay of Bengal now lies over South West Bay of Bengal off the Lankan and Tamil Nadu coast.
"Rainfall activity will continue over north coastal Tamil Nadu with heavy to very heavy rain over Tiruvallur, Kancheepuram and Chennai districts during the next 24 hours," a special bulletin issued at 8.30 am said today.
The mild, intermittent showers post noon yesterday became moderate and then heavy in some pockets last night inundating several more neighbourhoods including West Mambalam and the Guindy Industrial Estate.
As a result, bus, taxi, auto and suburban train services were affected.
While heavy waterlogging hindered free movement of vehicles, a "signalling snag," hit train services between the St Thomas Mount and Kodambakkam suburban section since 9.30 pm. Services were restored at 3.20 am today, Railway officials said.
Heavy traffic congestion and serpentine queue of vehicles were seen at the arterial Kathipara grade separator, Guindy intersection, Saidapet and all along till Velachery through the Raj Bhavan point.
Flight operations at the city airport were normal, airport officials said.
Chennai and Nungambakkam registered 18 cm rain and Meenambakkam in the southern suburb recorded 14 cm, till 8.30 am today, according to the Met department.