Heavy Rainfall Over Kerala-Coastal Karnataka: Light Rains After Mid-Week

Key Takeaways:

• Heavy rainfall is likely over Kerala and Coastal Karnataka for the next 72 hours, with isolated very heavy showers possible.
• Intense showers will extend into Goa, with the strongest activity expected today and tomorrow.
• Kerala and Coastal Karnataka are both rain deficient by about 24% despite being among the rainiest monsoon pockets.
• The monsoon surge will weaken after August 26, but light to moderate rainfall will continue during the remaining days of August.
• Forecast Validity: Next 72 hours.

The state of Kerala and Coastal Karnataka are likely to have heavy rainfall for the next 72 hours. Isolated places may have very heavy rainfall. Sharp and intense showers are likely to spill over to Goa as well. The monsoon surge will weaken after 26th August 2026. However, light to moderate rainfall activity will continue during the remaining days of August.

Both the state of Kerala and the sub-division of Coastal Karnataka are rain deficient by about 24%. Both are otherwise the rainiest pockets of the monsoon season. The monsoon triggers for these parts are the offshore trough and the emergence of monsoon systems over the Bay of Bengal. Currently, the seasonal north-south trough along the Western Ghats is quite weak. However, there is a low-pressure area over the Northwest Bay of Bengal and adjoining coastal parts of Odisha and West Bengal. The monsoon surge becomes strong from the Arabian Sea under the influence of such systems. Strong westerly flow from the sea, meeting head-on with the north-south oriented coastline, stimulates heavy monsoon showers. The activity invariably lasts for a couple of days and slows down with the inland shift of the system over the Bay.

Heavy rainfall is likely over Kerala and Coastal Karnataka over the next three days. Parts of Kerala were earlier ravaged by localized floods and landslides. The intense spell may repeat the same situation yet again. The heavy rains and thundershowers will extend to Coastal Karnataka and Goa as well. The places at risk will include Thiruvananthapuram, Kovalam, Kollam, Alappuzha, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudlu and Kasaragod. The coastline of Karnataka from Mangaluru to Karwar will also be vulnerable to strong bursts of monsoon showers.

The intensity and spread will be greater today and tomorrow. The pocket of heavy rains will shrink and become confined to South Coastal Kerala on 26th August. Weather activity will be more powerful during the late evening and night hours. Light to moderate rainfall, not accompanied by any ill effects, will continue for the rest of the week. The wet spell may marginally improve the seasonal rainfall deficit.