The Regional Meteorological Centre (RMC), Chennai, has issued an orange alert for heavy to very heavy rainfall in Chennai and several Tamil Nadu districts, warning that intense spells could disrupt normal life as two weather systems develop over the Bay of Bengal.
The alert is in force on Tuesday and applies through Thursday, according to the RMC. Chennai experienced widespread rain on Tuesday, while the northeast monsoon has strengthened across Tamil Nadu, bringing rainfall to coastal districts, the Cauvery delta and the Western Ghats.
The India Meteorological Department (IMD) has forecast the formation of a low-pressure area over the southwest Bay of Bengal. A second system is likely to develop over the southeast and adjoining east-central Bay of Bengal around October 23. The second system is expected to move north-northwestwards and intensify further, the report said.
The developing systems are being influenced by separate upper-air circulations. One circulation over the Gulf of Thailand and Myanmar is likely to move into the north Andaman Sea by Wednesday morning. Under its influence, the IMD expects a low-pressure area to form over the southeast and adjoining east-central Bay of Bengal around October 23.
Another upper-air cyclonic circulation is located over the southwest Bay of Bengal, off the north Tamil Nadu coast. The RMC said this circulation extends over the southwest Bay and adjoining Tamil Nadu coast and is likely to produce another low-pressure area over the same region within 24 hours.
A trough extending from this circulation towards north coastal Andhra Pradesh is also influencing the prevailing weather conditions. Together, the systems are contributing to widespread rainfall across parts of Tamil Nadu as the northeast monsoon gains momentum.
The orange alert covers Chennai along with several other districts where heavy to very heavy rainfall is possible. Such intense spells can affect road movement, public transport operations and routine activity in low-lying or poorly drained parts of urban areas, making local preparedness and timely weather updates important for residents and civic agencies.
The RMC has also issued a yellow alert for heavy rainfall at isolated places in Ranipet, Kanchipuram, Kallakurichi, Tiruchy, Ariyalur, Perambalur, Pudukkottai, Sivagangai, Tenkasi, Tirunelveli and Kanyakumari districts.
The immediate weather outlook will depend on the movement and intensification of the two systems. The RMC and IMD forecasts indicate that rainfall activity will remain significant across the affected areas through the alert period, with the next key developments linked to the expected formation of the low-pressure areas around October 23.
