Key Highlights:
- RMC forecasts moderate to heavy rain across 16 Tamil Nadu districts on Thursday, including Chennai, Tiruvallur, Chengalpattu and Kancheepuram.
- Heavy rain is likely at isolated places in the Nilgiris, Coimbatore, Karur, Tiruchirappalli, Perambalur, Ariyalur and Thanjavur, with winds up to 50 kmph.
- Rainfall intensity is expected to shift to northern Tamil Nadu on Saturday, and to western, central and southern districts on Sunday.
- Chennai will see partly cloudy conditions with evening or night showers, temperatures ranging between 27-36°C.
- Fishermen have been advised against venturing into the Bay of Bengal and Andaman Sea until Sunday due to winds reaching 65 kmph.
A Multi-Day Rain Forecast Across Tamil Nadu
The Regional Meteorological Centre (RMC) has forecast rain across Tamil Nadu on Thursday, with Chennai, Tiruvallur, Chengalpattu and Kancheepuram among 16 districts likely to receive moderate showers accompanied by thunderstorms and gusty winds. The forecast points to a sustained spell of rainfall activity moving across different parts of the state over the coming days rather than a single, isolated weather event.
The Weather Systems Driving the Rain
According to the RMC, a trough extends at about 0.9 km above mean sea level from north interior Karnataka to the Gulf of Mannar, passing through south interior Karnataka and Tamil Nadu. An additional upper-air circulation persists over coastal Andhra Pradesh and adjoining Rayalaseema at approximately 1.5 km above sea level, together forming the meteorological backdrop responsible for the rainfall pattern currently affecting the state.
Thursday's Heavy Rain Zones
Heavy rain is likely at isolated places in the Nilgiris, Coimbatore, Karur, Tiruchirappalli, Perambalur, Ariyalur and Thanjavur districts on Thursday, with thunderstorms, lightning and gusty winds reaching speeds of 40 to 50 kmph expected to accompany the rainfall in these areas.
Moderate Rain Across a Wider Area
Beyond the heavy rain zones, moderate rain is expected at a few places across other Western Ghats districts, as well as in Chennai, Tiruvallur, Chengalpattu, Kancheepuram, Ranipet, Vellore, Tirupattur, Salem, Tiruppur, Erode, Krishnagiri, Dharmapuri, Namakkal, Kallakurichi, Madurai and Sivaganga, giving a total of 16 districts under some form of rain alert for the day. Light rain may occur elsewhere across Tamil Nadu and in Puducherry, rounding out a forecast that covers much of the state to varying degrees.
How the Forecast Shifts Over the Coming Days
On Friday, isolated heavy rain is forecast specifically in the Nilgiris and Coimbatore districts, suggesting a temporary narrowing of the heavy rainfall zone before it expands again. Rainfall activity is then expected to intensify across parts of northern Tamil Nadu on Saturday, with heavy showers possible in 11 districts, including Tiruvallur, Vellore, Ranipet, Tirupattur, Tiruvannamalai, Salem, Dharmapuri and Krishnagiri.
By Sunday, the heaviest rainfall is expected to shift toward western, central and southern Tamil Nadu, with the Nilgiris, Coimbatore, Dindigul, Theni, Madurai, Sivaganga, Salem, Dharmapuri, Krishnagiri, Pudukkottai and Tiruchirappalli among the districts likely to be most affected. Light to moderate rain is expected to continue across the state until Tuesday, indicating that this weather system is set to influence conditions across Tamil Nadu for an extended period rather than clearing quickly.
What to Expect in Chennai
Chennai and its suburbs will experience partly cloudy conditions on Thursday, with light to moderate rain accompanied by thunderstorms likely in some areas during the evening or night. The maximum temperature is expected to remain between 35 and 36 degrees Celsius, while the minimum is likely to range from 27 to 28 degrees Celsius, indicating that despite the rain forecast, daytime temperatures in the city are expected to stay relatively warm.
A Warning for Fishermen
Given the wind conditions associated with this weather system, fishermen have been advised not to venture into parts of the Bay of Bengal and the Andaman Sea until Sunday, as wind speeds in these areas could reach up to 65 kmph. Notably, no warning has been issued for the Tamil Nadu coast or the Arabian Sea, indicating that the more severe wind conditions are currently confined to the Bay of Bengal and Andaman Sea region rather than affecting the state's immediate coastline.