The Indian maritime region is currently experiencing a rare convergence of two significant atmospheric disturbances as of October 22, 2025, prompting close monitoring from meteorological agencies. One system, originating in the Bay of Bengal, has already intensified into a depression and made landfall along the Tamil Nadu coast.
This Bay of Bengal depression is actively drawing in substantial moisture, resulting in pronounced and sustained rainfall across southern India, specifically impacting Tamil Nadu and the southern reaches of Andhra Pradesh. The India Meteorological Department (IMD) reported that this system was expected to intensify into a depression over the southwest and adjoining west-central Bay of Bengal off the north Tamil Nadu and south Andhra Pradesh coasts during the next 12 hours, before moving inland across north Tamil Nadu, Puducherry, and south Andhra Pradesh. Widespread rainfall has already been reported, with Cuddalore recording 174 mm and Puducherry 147 mm between Tuesday and Wednesday morning.
Simultaneously, a separate, well-marked low-pressure area over the southeast Arabian Sea has intensified into a depression. This system was positioned approximately 630 km west-southwest of Aminidivi (Lakshadweep) and is forecast to move slowly north-northwestward over the ensuing twenty-four hours. The dual activity has kept the northeast monsoon active, with extremely heavy rainfall alerts issued for North Tamil Nadu, Puducherry, Karaikal, Coastal Andhra Pradesh, and Rayalaseema for October 22.
Beyond the immediate coastal impact, the massive influx of atmospheric moisture is creating secondary weather effects further north. In Kolkata, for example, daytime high temperatures are hovering between 32°C and 33°C, with nighttime readings near 25°C, figures that disrupt typical seasonal expectations for the region. While the Bay of Bengal system is not anticipated to have a direct, immediate bearing on West Bengal during the current festive period, light to moderate precipitation is forecast for the area later this approaching weekend.
Meteorological analysis suggests that such simultaneous vortex occurrences are frequently linked to specific configurations of the Madden-Julian Oscillation (MJO) phase. Furthermore, sea surface temperatures in the Arabian Sea during this period in 2025 show anomalies exceeding 1.5°C above the long-term average, providing the necessary thermal energy to sustain and intensify these dual systems.