Weather watch: South Tamil Nadu makes gains from easterly wave

The prevailing easterly wave activity over the Bay of Bengal is expected to trigger scattered to fairly widespread rain/thundershowers over Tamil Nadu, Puducherry, Karaikal, Kerala, Mahe and Lakshadweep for four more days, according to an update by the India Meteorological Department (IMD).

The easterly wave has also spawned a cyclonic circulation over the South-West Bay of Bengal off the Sri Lanka coast, over the Comorin area and adjoining Sri Lanka. This circulation is helping to pull in the rain bands associated with the easterly wave to both over Sri Lanka and southern parts of Tamil Nadu.

Showery over Sri Lanka

The Sri Lankan Meteorological Department said this (Thursday) morning that showery conditions over the Northern and Eastern provinces may scale up during the next few days. It attributed this to the revival of the North-East monsoon facilitated by the prevailing easterly wave across the Bay of Bengal.

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The IMD isolated heavy has been forecast over Tamil Nadu, Puducherry and Karaikal until Saturday and over Kerala and Mahe today and tomorrow (Thursday and Friday). The European Centre for Medium-Range Weather Forecasts (ECMWF) said that Central and South Tamil Nadu would make gains till Friday morning.

European model outlook

The ECMWF-IFS-HRES model sees rain spread out along the coast from Puducherry to Kaveripattinam, Rameswaram and Thoothukudi to Kanyakumari during this period. Rain is also forecast for parts of the delta area as and along the ghats across Thanjavur, Tiruchi, Dindigul, Madurai and Coimbatore.

Heavier rain is forecast across this region and parts of adjoining Kerala on Saturday with a fresh wave materialising along the Puducherry-Rameshwaram coastal belt, the ECMWF model said. The northern parts of Tami Nadu, including Chennai, are likely to sit out of this session.

North TN to dry up from today

Private forecaster Skymet Weather too agreed, saying that rains may peter out from North Tamil Nadu from today (Thursday). The Nagapattinam, Thiruvarur, Pudukkottai, Sivaganga, Ramanathapuram, Thoothukudi, Nagercoil and Tirunelveli districts in the South may get moderate to heavy rain until Saturday.

Chennai and Puducherry may get light to moderate rain until Saturday, Skymet said. The interior districts of Tamil Nadu may also get moderate showers during this period. But the intensity will be much less than in the coastal areas. This could well be the last heavy spell for the State from the North-East Monsoon.