Kerala Heavy Rain Alert: Isolated Heavy Showers Likely From 17–20 September

Key Takeaways:

• Isolated heavy rainfall of 7–11 cm in 24 hours is possible across parts of Kerala from 17–20 September.
• The wettest phase is expected on 17–18 September, with fairly widespread rainfall over Kerala and Lakshadweep.
• Idukki and Pathanamthitta require attention due to heavy-rain potential and the influence of the Western Ghats.
• Thunderstorms, lightning and gusty winds of 30–40 kmph may affect Kerala on 18 and 19 September.
• Forecast Validity: Next 2 to 3 days.

Kerala is entering another wetter spell after the southwest monsoon remained weak over the state earlier this week. Isolated heavy rainfall is possible from 17–20 September, with thunderstorms and gusty winds possible during part of the period.

Rainfall should become fairly widespread across Kerala and Lakshadweep on Thursday and Friday before coverage decreases over the weekend.

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Forecast Upgraded After Weak Monsoon Day

Rain had occurred at only one or two places in the state during the last 24 hours. Urumi in Kozhikode district recorded 3 cm, while Idukki and Udumbannoor received 2 cm each.

The updated outlook is considerably wetter. Rain or thundershowers are expected at many places across Kerala on 17 and 18 September.

Isolated heavy rainfall—between 7 cm and 11 cm in 24 hours—is forecast from Thursday through Sunday. The warning initially covers Pathanamthitta and Idukki, with Idukki remaining highlighted on Friday. Later warning locations include northern and central districts.

Heavy rain will be local rather than uniform. Many places may receive ordinary monsoon showers, while one or two locations experience much higher totals.

Several Features Support Rainfall

A trough runs from North Interior Karnataka to the Gulf of Mannar across South Interior Karnataka and Tamil Nadu. A trough is an elongated zone of relatively low pressure where winds converge and humid air rises.

A lower-level circulation is also present over South Coastal Andhra Pradesh and adjoining Rayalaseema. Together, these features can organise moisture and thunderstorms across southern India.

Moist winds rising along the Western Ghats may further increase rainfall over Kerala’s hill districts. This terrain-induced ascent, called orographic lifting, is one reason Idukki and Pathanamthitta require particular attention.

Benefits and Risks

The rain may improve soil moisture, plantation conditions and smaller reservoir inflows after repeated weak phases. It could benefit coconut, rubber, black pepper, ginger and turmeric where rainfall remains well distributed.

Intense local showers, however, may waterlog roads and low-lying fields. Saturated or unstable slopes could experience landslips, particularly in the high ranges.

Poor visibility and falling branches may delay road travel. Thunderstorms with lightning and gusts of 30–40 kmph are possible over Kerala on 18 and 19 September.

Farmers should clear field drainage, support banana plants and trellised crops, and avoid applying fertiliser or pesticide immediately before rain. Travellers should use district forecasts because conditions may differ sharply over short distances.

The wettest phase should occur on 17–18 September, but isolated heavy falls may continue through Sunday. Updated district warnings remain essential because the geographic focus changes during the four-day spell.