Chennai Swelters as Mercury Hits 40.2°C; Heavy Rain Forecast for Tamil Nadu

Key facts

• Chennai recorded 38°C at Nungambakkam and 40.2°C at Meenambakkam on Thursday.
• The India Meteorological Department forecasts heavy rainfall in Nilgiris and Coimbatore for three days.
• A trough of low pressure persists at 0.9 km above mean sea level, extending from north interior Karnataka to the Gulf of Mannar.
• Heavy rainfall is expected in Erode, Salem, Dharmapuri, and Krishnagiri over two days.
• Isolated heavy rainfall likely in Tiruppur, Dindigul, and Theni on May 1.
• On May 2, heavy rain predicted in Dindigul, Theni, Madurai, Sivaganga, and Virudhunagar.
• Fishermen advised caution along the southern coast due to adverse weather.

Heat Peaks as Rain Looms

Chennai on Thursday recorded its highest daytime temperatures of the year, with Nungambakkam reaching 38°C and Meenambakkam hitting 40.2°C. The mercury is expected to climb further, potentially touching 41°C on Friday, accompanied by high humidity. While the city swelters, the India Meteorological Department's Regional Meteorological Centre in Chennai has forecast moderate to heavy rainfall across several parts of Tamil Nadu over the coming days. The contrasting weather patterns highlight the region's volatile pre-monsoon conditions.

Atmospheric Setup Triggers Widespread Rain

A trough of low pressure persists at an altitude of about 0.9 km above mean sea level, extending from north interior Karnataka to the Gulf of Mannar through south interior Karnataka and Tamil Nadu. This system is expected to trigger widespread rainfall activity across multiple districts. Meteorologists attribute the current spell to localised atmospheric instability rather than the southwest monsoon, which remains weeks away. Light to moderate rainfall, accompanied by thunderstorms and lightning, is expected at isolated places along the Western Ghats districts, coastal belts, delta regions, and the Karaikal area.

Heavy Rain Warning for Western Ghats Districts

Significant heavy rainfall has been forecast for the Nilgiris and Coimbatore districts for the next three days, raising the possibility of localised disruptions in hilly and adjoining areas. Authorities have advised residents in these districts to remain cautious, particularly in regions prone to landslides or waterlogging. Additionally, districts such as Erode, Salem, Dharmapuri, and Krishnagiri are expected to receive heavy rainfall over the next two days. The weather system is gradually shifting southward, bringing more districts under its influence.

Southern Districts Bracing for Rain on May 1-2

On May 1, isolated heavy rainfall is likely in Tiruppur, Dindigul, and Theni districts. The intensity is expected to persist on May 2, with heavy rainfall predicted in parts of Dindigul, Theni, Madurai, Sivaganga, and Virudhunagar districts. Officials have urged local administrations to remain alert and ensure preparedness, especially in low-lying and flood-prone areas. The state machinery is on standby to respond to any weather-related emergencies.

Fishermen and Coastal Communities on Alert

Fishermen have been advised to exercise caution along the southern coast due to potential adverse weather conditions. The department warned of rough seas and gusty winds that could pose risks to small vessels. Coastal communities are being urged to stay informed about weather updates and avoid venturing into the sea until conditions improve. The advisory comes as part of the broader preparedness measures.

Pre-Monsoon Pattern Brings Relief and Risk

While the rain offers some relief from the scorching heat, it also brings the risk of localised flooding and landslides, particularly in the Western Ghats districts. The current spell is a typical pre-monsoon phenomenon driven by local atmospheric instability. With the southwest monsoon still weeks away, residents and authorities must navigate the dual challenges of extreme heat and sudden downpours. The IMD continues to monitor the situation and will issue updates as the weather system evolves.

The bottom line

• Chennai's highest temperature of the year so far was 40.2°C at Meenambakkam, with forecasts of 41°C.
• A trough of low pressure is driving widespread rainfall across Tamil Nadu, unrelated to the monsoon.
• Nilgiris and Coimbatore face heavy rain for three days, with landslide risks.
• Southern districts like Dindigul, Theni, and Madurai will see heavy rain on May 1-2.
• Fishermen are advised to stay cautious along the southern coast.
• Local administrations are on alert for flooding and waterlogging in vulnerable areas.