Tamil Nadu is bracing for heavy to very heavy rainfall through 26 October, as a fresh weather system forming over the Bay of Bengal on Friday could intensify into a cyclonic storm, according to the Chennai Meteorological Centre. While the prospective cyclone is not expected to make a direct hit on Tamil Nadu, the broader monsoon surge is already lashing large swathes of the state.

Bay of Bengal System: What Forecasters Are Watching

Chennai Meteorological Centre director Durai said conditions are favourable for a low-pressure area to develop over the southeast and adjoining east-central Bay of Bengal. The system is expected to strengthen and track west-southwestwards, with the possibility of escalating into a cyclonic storm.

Durai clarified that the prospective cyclone is not projected to directly affect Tamil Nadu at this stage. Its precise intensity and track will become clearer as the weather system evolves, and further advisories will be issued accordingly. A separate low-pressure system over the southwest Bay of Bengal and adjoining southern Tamil Nadu is also unlikely to intensify significantly, though it may still deliver very heavy rain to southern districts.

Current Rainfall: Districts Already Hit Hard

During the 24 hours ending at 8:30 am on Wednesday, three districts recorded very heavy rain and 13 districts experienced heavy rain. MGR Nagar in Chennai logged the highest single-station rainfall of 15.4 cm during that period.

The northeast monsoon is gathering strength, and the meteorological department has issued a broad warning for Tamil Nadu and Puducherry, flagging the possibility of very heavy rain, thunderstorms, lightning, and squally weather through 26 October.

District-Wise Forecast Through the Weekend

For Thursday, intense spells are forecast across southern, western, and delta districts, including Tirunelveli, Thoothukudi, Kanniyakumari, Tenkasi, Virudhunagar, Ramanathapuram, Theni, Dindigul, and Madurai. Districts including Coimbatore, the Nilgiris, Sivaganga, Pudukkottai, Thanjavur, Tiruvarur, Nagapattinam, and Mayiladuthurai are also likely to receive significant rainfall, with thunderstorms, lightning, and gusty winds possible at several locations.

On Friday, isolated heavy to very heavy rain is forecast for Kanyakumari, Coimbatore, and the Nilgiris. Heavy showers are also likely across Erode, Salem, Namakkal, Karur, Tiruchi, and Theni, with rain extending to several additional districts.

Chennai itself is expected to receive moderate rain on 22 October and 24 October, followed by heavy rain on 25 October.

Arabian Sea System and the Longer-Range Outlook

Durai also noted that a separate system over the Arabian Sea has moved west-northwestwards toward Somalia and is not a concern for India at present. Looking further ahead, he indicated that Tamil Nadu could receive above-normal northeast monsoon rainfall in November, with seasonal rain potentially extending into the second week of January.

The multi-system weather pattern underscores an active northeast monsoon season, and authorities are expected to issue updated advisories as the Bay system's track firms up over the coming days.