Cyclone Ditwah’s unusual stall leads to prolonged rains in Tamil Nadu

Meteorologists noted that Cyclone Ditwah and its remnant stalled for several hours and moved slowly due to being trapped in a calm ‘col’ zone between two opposing anticyclonic circulations in the upper atmosphere, resulting in prolonged rainfall.

While the system is expected to move away from the TN coast by Monday, December 1, 2025, it remains stationary for a few hours and attracts more moisture, forming new rain-bearing cloud bands that hit the region near Tiruvallur and Chennai, they said.

To read:Cyclone Ditwah LIVE updates

Regional Meteorological Center Director (Additional Officer) B. Amudha said that the system, located between two anticyclonic circulations, oscillates under the push and pull effect of the surrounding winds. “Such microphysical changes that occur continuously in the atmosphere are difficult to predict well in advance, and rapid changes can only be followed over short periods of time. Interactions between land, ocean and atmospheric changes contribute to cloud dynamics in a complex way. Our understanding of the internal dynamics of tropical cyclones is not yet complete,” he said.

Meteorologists have noted that predicting such behavior in the tropics is difficult, especially due to the limitations of weather models. Sometimes weather models cannot predict when weather systems stop moving.

YEA Raj, former Deputy Director of Meteorology, Chennai, said that cyclone Ditwah was a marginal cyclone with wind speed reaching up to 40 knots. The noticeable slowdown of the system was unexpected, and movement was as slow as 2-3 km per hour.

Typically depressions or tornadoes slow down before reoccurring. This system was bending to the southwest instead of the usual north or east direction, which is rare for tropical cyclones. The systems will accelerate as they move northward.

He added that in the period between 1981 and 2024, only three weather systems realigned and moved towards the southwest in November 1996, November 2013 and December 2018. The delay in precipitation was due to weather conditions, as the behavior of the system was affected by rapidly changing atmospheric conditions.