Monsoon withdraws from parts of Rajasthan

Southwest monsoon withdrawal delayed in Rajasthan, active rainfall season with unexpected patterns, transition to northeast monsoon expected in October.

The Southwest monsoon has begun withdrawing from Rajasthan, a week later than its scheduled date. Though withdrawal has begun from West Rajasthan and Kachchh, the monsoon is expected to withdraw from Punjab, Haryana and Gujarat during the next 24 hours, according to a bulletin from the India Meteorological Department (IMD).

The year, on the whole, has seen a very active spell of rainfall. From June 1 to September 23, monsoon rainfall is 5% more than what is usual. For September, so far the monsoon rainfall is 3% less than what is usual for the month. This is contrary to the IMD’s expectations. In its outlook for September, the agency said on August 31 that monsoon rainfall was likely to be 9% above what is usual for the month (16.8 cm). This was premised on a La Nina, or a cooling of the Central Pacific, expected to firmly take root this month. La Ninas usually correspond to above average rainfall in India.

Rainfall in August turned out to be much more than the IMD had anticipated at the beginning of the month. August — the second rainiest of the monsoon months — was projected to receive 6% more than normal rainfall but India ended up getting 15% more than normal rainfall. This was largely due to multiple active moisture-laden incursions from the Arabian Sea and the Bay of Bengal, called ‘depressions,’ that contributed to the heavy rainfall.

Though the withdrawal of the monsoon has begun, it will be at least until mid October before the southwest monsoon fully withdraws and is replaced by the north-eastern monsoon which brings heavy rain to a few southern States, such as Tamil Nadu, Kerala and parts of Andhra Pradesh. However, all rainfall after September 30 isn’t counted as monsoon rainfall.