Tamil Nadu Weatherman Pradeep John has warned that rainfall is likely to increase across Chennai as rain clouds move towards the city.

In a post on his X account, Pradeep John said several locations in the Chennai, Chengalpattu, Tiruvallur and Kancheepuram (KTCC) region had recorded more than 100 mm of rainfall, putting the region at the top of Tamil Nadu's rainfall chart.

He said more rain clouds were moving towards Chennai and several places in the city could cross the 100-mm mark before 8.30 am. By the time rainfall readings are reset at 8.30 am, some locations could record between 100 mm and 150 mm of rain, he added.

Rainfall likely to increase

The rain clouds moving towards Chennai are expected to increase rainfall across the city. The weather system is bringing rain at a time when many people are returning to Chennai from their hometowns after the holidays.

Puzhal lake storage crosses 5 TMC

Meanwhile, the water storage in Puzhal Lake, one of Chennai's key drinking water reservoirs, has crossed 5 TMC as of October 21, 2026.

Pradeep John said the lake was receiving a good inflow because of its proximity to Chennai. However, more rainfall is needed in the catchment area to sustain the inflow.

He added that light rainfall was expected over the next three days, which could help maintain a steady inflow into the reservoir.

Up to 5 am on October 21, a total of 1,212 complaints were registered. The majority pertained to waterlogging and inundation, alongside over 50 grievances concerning tree falls and non-functional streetlights, commissioner said.  Most waterlogging and tree-falling complaints have already been cleared. Streetlight repairs have been mandated for resolution within 24 hours. Complaints are strictly closed in the system only after field engineers upload before-and-after photographs.

The majority of complaints originated from the Core City region attributed to higher population density and awareness of the 1913 helpline alongside inputs from North Chennai zones like Manali and Madhavaram.

Complaints continue to be tracked across multiple channels, including the 1913 helpline, social media, the online web portal, the PGR mobile app, and media reports, he added.

The Regional Meteorological Centre (RMC) issued an alert valid until 10 am forecasting light to moderate rain with thunderstorms and lightning at isolated places across Chennai, Tiruvallur, Ranipettai, Chengalpattu, Kancheepuram, Villupuram, Cuddalore, Mayiladuthurai, Nagappattinam, Thiruvarur, Thanjavur, Pudukottai, Ramanathapuram, Thoothukudi, Tirunelveli, and Kanyakumari districts, as well as Karaikal and Puducherry

Very heavy rainfall, recorded in three areas, led by Vadapalani with 132.9 mm, Saidapet with 125.2 mm, and Alandur with 119.4 mm. Heavy to moderate spells at Maduravoyal recorded 112.5 mm, Madipakkam saw 114.6 mm, Valasaravakkam logged 109.6 mm, Nungambakkam recorded 106.8 mm, Adyar registered 104.1 mm, and Korattur hit 96 mm.

According to the India Meteorological Department (IMD), widespread rainfall is likely over Tamil Nadu, Puducherry, and Karaikal today (October 21) and tomorrow (October 22), followed by isolated to scattered rainfall between October 23 and October 26.

Heavy to very heavy rain, accompanied by thunderstorms, lightning, and gusty winds reaching 40 to 50 kmph is likely to occur at isolated places over Thoothukudi, Tirunelveli, and Kanniyakumari districts on Wednesday. Heavy to very heavy rainfall will continue in Tenkasi, Virudhunagar, and Ramanathapuram districts on Thursday.

Under similar wind conditions, heavy rain with thunderstorms and lightning is expected at one or two places over the Nilgiris, Coimbatore, Erode, Tiruppur, Namakkal, Karur, Theni, Dindigul, Tenkasi, Madurai, Virudhunagar, Pudukkottai, Thanjavur, Tiruvarur, Nagapattinam, Mayiladuthurai, Sivagangai, and Ramanathapuram, as well as the Karaikal area.

In Chennai, the maximum temperature is expected to hover around 30 degrees Celsius, with the minimum temperature dipping to 25 degrees Celsius on Wednesday.

CHENNAI: Schools in Chennai, Tiruvallur, Chengalpattu, Kancheepuram and Ranipet districts will remain closed on Wednesday (October 21) following heavy overnight rain, with district collectors announcing a holiday.

Heavy rain lashed several parts of Chennai, Chengalpattu and Tiruvallur districts through the night, while the Regional Meteorological Centre (RMC) has forecast further rainfall.

Meanwhile, the upper-air cyclonic circulation over the southwest Bay of Bengal and adjoining Tamil Nadu coast persists, with a low-pressure area likely to form over the same region within the next 12 hours, according to the Indian Meteorological Department's bulletin on Tuesday night.

Another upper-air cyclonic circulation over the Gulf of Thailand and adjoining areas of Thailand and Myanmar is likely to move into the north Andaman Sea by today morning. Under its influence, a low-pressure area is likely to form over the southeast and adjoining east-central Bay of Bengal around October 23 and intensify over the following three days.

Due to the twin weather systems, heavy to very heavy rain is likely to continue across Tamil Nadu, Puducherry and Karaikal until October 26, the RMC has forecast. Thunderstorms and lightning, accompanied by gusty winds reaching speeds of 40-50 kmph, are likely at one or two places across Tamil Nadu, Puducherry and Karaikal until October 26.