Heavy rainfall, thunderstorms expected across India on May 18

Monsoon intensifies eastern regions; coastal alerts issued for mariners and fishermen

Monsoon Picks Up Pace Nationwide

India faces widespread heavy rainfall and severe weather on May 18 as the southwest monsoon continues its rapid northward advance, according to the India Meteorological Department bulletin released late evening on May 17. The National Weather Forecasting Centre has issued alerts across multiple regions, signalling potentially disruptive conditions in urban centres and coastal areas over the next 24 hours.

Heavy Downpour Likely Over Eastern, Northeastern States

The most intense rainfall activity is forecast over the Andaman & Nicobar Islands, Arunachal Pradesh, Assam & Meghalaya, Coastal Karnataka, Kerala & Mahe, Lakshadweep and the Tamil Nadu coast. Officials have flagged isolated very heavy rainfall—exceeding 115 mm in 24 hours—as likely in several locations within these regions.

The northeast remains particularly vulnerable. Sub-Himalayan West Bengal and Sikkim are expected to receive heavy showers, with similar conditions anticipated over the Nagaland, Manipur, Mizoram and Tripura region. Local authorities in these areas have already begun preparedness measures.

Thunderstorms, Hailstorms in Focus

Beyond rainfall, thunderstorm activity accompanied by lightning and gusts reaching 40-50 kmph are expected over Assam & Meghalaya, Chhattisgarh, Coastal Karnataka, Gangetic West Bengal, Jharkhand, Kerala & Mahe and Lakshadweep. Interior Karnataka faces the additional risk of isolated hailstorm activity—a concern for local agriculture and infrastructure.

Heat Waves Continue in Pockets Across India

Contrasting sharply with the monsoon rains, isolated heat wave conditions are anticipated across East Uttar Pradesh, Haryana, Chandigarh & Delhi, Madhya Pradesh, Marathwada, Punjab, Rajasthan, Telangana and Vidarbha. Severe heat wave conditions may grip isolated pockets of West Uttar Pradesh, prompting health advisories for vulnerable populations.

The highest maximum temperature recorded on May 16 stood at 46°C in Vidarbha's Amraoti and Wardha districts.

Fishermen, Mariners Advised to Stay Ashore

The IMD has issued squally weather warnings for multiple maritime zones. Fishermen operating in the Arabian Sea are advised to avoid waters off the Somalia coast and southwest Arabian Sea from May 18 onwards, where wind speeds of 45-55 kmph gusting to 65 kmph are anticipated.

Along the Bay of Bengal, conditions remain similarly hazardous. Squally weather with winds reaching 40-50 kmph is expected over the Gulf of Mannar, Comorin area, and most parts of south and central Bay of Bengal. The Andaman Sea has also been placed under maritime alert.

Impact and Ground Reality

Field reports from overnight May 17 indicate rainfall distribution favouring the eastern and northeastern regions, with at most places recording precipitation over Arunachal Pradesh, Assam & Meghalaya, Sub-Himalayan West Bengal & Sikkim and Lakshadweep. Tea estates in Jalpaiguri district, West Bengal logged 14 cm of rainfall within 24 hours ending 8:30 am on May 17.

Urban planners in major cities have flagged potential water logging in low-lying areas and underpasses. Traffic advisories are being circulated preemptively across metros expecting heavier downpours by afternoon.

Monsoon's Northern Limit Continues March

The monsoon's northern limit—a key meteorological marker—continues to advance through geographic coordinates 5°N/75°E, 6°N/79°E, 8°N/85°E, 10.5°N/90°E, 13.5°N/95°E, and 15.5°N/98°E. The IMD forecasts further progression into southeast Arabian Sea, southwest and southeast Bay of Bengal, remaining parts of Andaman Islands and Andaman Sea, and eastcentral Bay of Bengal during the next 48-72 hours.

The Southwest Monsoon onset over Kerala—considered the official commencement of the seasonal system—remains on track for May 26, with a model error margin of ± 4 days. This timing aligns with climatological norms, offering some relief to agricultural zones awaiting the seasonal moisture influx.

Agricultural and Livestock Advisory

The meteorological department has issued farm advisories recommending enhanced drainage in paddy, arecanut and mango orchards across South Interior Karnataka. In regions experiencing hailstorm risk, farmers have been advised to postpone intercultural operations and fertiliser applications. Livestock owners in heavy rainfall zones are urged to shelter animals indoors and maintain feed and fodder reserves in dry storage.

What Residents Should Do

Authorities suggest residents check traffic routes before commuting, follow issued advisories closely, and avoid areas with historical water logging problems. Those living in vulnerable structures are advised to relocate temporarily. During thunderstorms, staying indoors with doors and windows closed remains the safest option; outdoor shelter under trees is strictly discouraged due to lightning risk.