Monsoon begins retreat from western Rajasthan; IMD flags active rain week ahead

The southwest monsoon has begun its annual retreat from northwest India, with the withdrawal line running through western Rajasthan and adjoining areas, the India Meteorological Department said on Sunday.

As of 20 September, the line of withdrawal passes through Ramgarh, Mohangarh, Phalodi and Khajuwala. The retreat typically starts from western Rajasthan in September before gradually extending to other parts of northwest and central India, paced by rainfall patterns and atmospheric conditions.

The process is significant because the monsoon delivers roughly 70% of India's annual rainfall, and its withdrawal signals the shift towards the post-monsoon season.

Rain to stay active across several regions

Even as the monsoon begins to pull back from the northwest, the weather office expects rainfall to remain vigorous over several parts of the country in the coming week.

In the east, widespread showers are likely over the Andaman and Nicobar Islands and Gangetic West Bengal from 21 to 26 September. Odisha, Jharkhand and Sub-Himalayan West Bengal and Sikkim are expected to see widespread rain between 22 and 26 September, while Bihar may receive widespread rainfall from 24 to 26 September.

Central India is also set for significant rain. Chhattisgarh and Vidarbha are forecast to receive widespread showers through 21-26 September, and east Madhya Pradesh during 23-26 September.

In the south, Kerala, coastal Karnataka and parts of Karnataka are likely to witness widespread rainfall during the week, with Telangana and coastal Andhra Pradesh receiving rain at different times. The North-East is expected to see widespread rainfall and thunderstorms over Assam, Meghalaya and adjoining areas from 21 to 25 September.

In the northwest, east Uttar Pradesh may get widespread rain accompanied by thunderstorms and lightning on 25-26 September, while other parts of the region are likely to see isolated showers.

Seasonal rainfall remains below normal

Cumulative rainfall for the southwest monsoon season stood at 695.6 mm during 1 June to 19 September, about 15% below the normal of 817.2 mm.

In the 24 hours ending 8.30 am on Sunday, heavy rain lashed several parts of the country. Telangana, Rayalaseema and Tamil Nadu recorded very heavy rainfall, with isolated places in the three regions receiving 12-20 cm. Heavy rainfall of 7-11 cm was reported in parts of Odisha, Madhya Pradesh, the Andaman and Nicobar Islands, Chhattisgarh, Assam, Nagaland and south interior Karnataka.

The intense spell comes amid heightened monsoon activity over southern, eastern and central India, with more heavy rain forecast in several regions over the coming days.