Southwest Monsoon 2021 commenced its withdrawal from West Rajasthan on 06thOctober, against its revised normal date of 17thSeptember. This is the 2nd most delayed withdrawal since 1960. Year 2019 holds the record of extreme lag as the withdrawal process started on 09thOctober. However, 2019 also holds the distinction of completing withdrawal in just one week, 16thOctober. The monsoon withdrawal started on September 28 last year, October 9 in 2019, September 27 in 2017 and September 15 in 2016.
Normally, any withdrawal commencing in October follow a speedy process like in 2019, but 2021 possibly is an exception wherein the withdrawal line is stuck and stationary nearly for the last 10days. The initial phase of withdrawal was quite rapid as it vacated entire North India and some parts of central region within 06days. Multiple weather systems forming on either side of the coastline stalled the process thereafter. Rainfall continued over Madhya Pradesh, Maharashtra, Bihar, West Bengal, Odisha, Chhattisgarh and Northeast India.
Timely withdrawal of monsoon, denies access to any further weather systems and restrict their reach over north India and adjoining region. In view of late withdrawal, the low pressure area forming over Bay of Bengal could reach up to North Madhya Pradesh and further recourse northward, to impact Delhi, Uttarakhand and West Uttar Pradesh. There was another weather system trailing behind, lingering over Bay of Bengal and coastal areas.
This combination pushed strong stream of easterly winds all along the Indo Gangetic plains, penetrating right up to Delhi, Uttarakhand and Himachal Pradesh. Under the combined influence of a western disturbance and this low pressure area, the state of Uttarakhand was deluged with unprecedented heavy rainfall, triggering massive landslides, flurry of floods and overflowing water bodies. As it happens, the water bodies and land slides keep responding for days together, even after the rainfall stops.
In the meantime, the trailing system brought heavy downpour over Bihar, Sub Himalayan West Bengal and Assam region. Heavy thunderstorm accompanied with strong winds resulted lodging of standing crops in Bihar and neighborhood. A late withdrawal of monsoon and extended rainfall has spelt trouble for the farmers over Northeast India. Monsoon is still hanging around over parts of Assam, Manipur, Mizoram and Tripura.
Southwest Monsoon appears to be in its last leg now. It is likely to resume withdrawal by tomorrow from the eastern parts. Further retreat from the southern parts is expected in the subsequent 2-3 days. Monsoon is on the verge of making complete exit by 26thOctober.