Severe cyclone threat looms large near Chennai as IMD GFS predict landfall by Thursday!

Tuesday, October 15: A well-marked low has been reigning terror over Chennai since yesterday, with heavy rains pounding the city last night and this morning. The Tamil Nadu capital’s infrastructure is already drowning in rainwater, but forecasts estimate that the worst is yet to come.

According to the India Meteorological Department (IMD), the system currently stationed over the Bay of Bengal is expected to intensify in the coming days and develop into a depression within the next 48 to 72 hours. And certain weather models predict the birth to a powerful cyclone that could impact coastal regions, including Chennai.

The development of this storm is being fueled by the Madden-Julian Oscillation (MJO), currently in its active phase (phase 4), which is known to enhance convective activity and may cause the system to intensify. Current forecasts suggest that the cyclone will move towards the North Tamil Nadu, Puducherry, and South Andhra Pradesh coasts. Some models, including IMD's Global Forecast System (GFS), predict the system could evolve into a severe cyclonic storm by Wednesday, October 16, and make landfall near Chennai on Thursday, October 17.

The state government has declared a holiday for schools and colleges in the city and surrounding districts.

Conflicting predictions on storm intensity

While various forecasting models agree that a storm is forming, they differ on the system's strength and path. According to meteorologists from The Weather Channel, the low-pressure area has been clearly visible over the central-southern Bay of Bengal since Tuesday morning. It is expected to move west-northwestward towards the Andhra Pradesh and Tamil Nadu coasts by Thursday. Most numerical weather models currently project that the system will intensify into a depression but stop short of becoming a full-fledged cyclonic storm.

However, IMD GFS stands out by predicting rapid intensification into a severe cyclonic storm, with a possible landfall just south of Chennai on Thursday. Meanwhile, the European model ECMWF — renowned for accurate cyclone forecasting — suggests that the system may remain a low-pressure area as it crosses the coast, with no further intensification.

If the storm does reach cyclone status, it will be named "Cyclone Dana," following a proposal by Qatar under the World Meteorological Organisation’s naming guidelines.

Weather warnings for coastal regions

The brewing system is expected to bring widespread heavy rains across Tamil Nadu, Puducherry, Karaikal, and Coastal Andhra Pradesh over the next few days. The IMD has issued a red warning (indicating the need for immediate action) for these areas on October 16, with an orange alert (be prepared) for October 15 and 17.

Within Tamil Nadu, districts such as Chennai, Tiruvallur, Kancheepuram, and Nagapattinam are under a red warning, with extremely heavy rainfall expected on October 16. Winds are predicted to reach speeds of 40-50 km/h, with gusts of up to 60 km/h along the coast, prompting the IMD to advise fishermen to stay ashore as sea conditions worsen.

Other potential impacts include localised flooding of roads, waterlogging and closure of underpasses, reduction in visibility, disruption of traffic and minor damage to kutcha roads. As the storm nears, coastal residents are urged to stay alert and take necessary precautions to safeguard lives and property.