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Two cyclonic storms are predicted to form in the Bay of Bengal, with a potential Fujiwhara interaction.
This could increase the uncertainty about their paths and intensity.
IMD is closely monitoring these systems, which could impact South and Southeast Asia.
There could be two cyclonic storms in the Bay of Bengal in the following week, with a possibility of a Fujiwhara type interaction between the two. This increases the uncertainty of the resulting cyclonic system, its track and intensity, keeping a large swathe of population of South and Southeast Asia on alert.
The India Meteorological Department (IMD), in its latest tropical weather outlook, tracked the presence of a well marked low pressure area over Malaysia and the adjoining the Straits of Malacca in the morning of November 24, 2025. IMD predicted that the system would move in a west-northwestward direction and strengthen into a depression over South Andaman Sea by the morning of November 25.
The system would continue moving in the same direction and intensify into a cyclone over south Bay of Bengal in the subsequent 48 hours (by the morning of November 27), according to IMD.
The weather agency is also tracking an upper air cyclonic circulation over Comorin area, which could induce a low pressure area over the same region of southwest Bay of Bengal and Sri Lanka on November 25. IMD has also predicted the formation of a depression from this system in the following couple of days but has not yet said anything about the formation of a cyclone.
Data from the Global Forecasting System (GFS) of the United States and the European Centre for Medium-range Weather Forecasting (ECMWF), as represented on the weather visualisation platform Windy, diverges on the formation, track and intensity of the two cyclonic systems.
The GFS data on Windy, on November 24 (evening 4:45 pm) forecast the two systems intensifying into depressions and starting to interact, similar to Fujiwhara effect, on November 26. By November 27 the systems come closer and start moving in a common direction towards north-northeast. GFS is predicting that the storm coming from the Andaman Sea may gain wind speeds from the storm coming from the Comorin area and move towards the Myanmar coast.
The Fujiwhara effect occurs when two cyclonic storms in the ocean form in the same region and their wind circulations start interacting with each other in the middle to upper layers of the atmosphere. This interaction of winds creates a bond between the two storms, through which they start influencing each other.
The influence could be weak or strong and could lead to either of the storms gaining wind speeds and strength or both storms dissipating. The exact dynamics of the interaction are still challenging for weather models to forecast accurately.
ECMWF data on Windy is showing that the Fujiwhara type interaction is making the storm coming from the Comorin area gain wind speeds from the storm coming from the South Andaman Sea and move along the eastern coast of India.
The vast difference in the current forecasts is the reason the IMD and other weather departments will have to keep a close tab on the movement and interaction of these two cyclonic systems so they are able to alert vulnerable populations along the coast of Sri Lanka, eastern India, Bangladesh and Myanmar in time.