Context: According to the regional center of India Meteorological Department, the current monsoon break that started on August 7, 2023 has finally ended on August 18, 2023.

• This monsoonal break is the third-longest in this century, after 2002 and 2009.

What is Monsoonal break?

• A monsoonal break occurs when the monsoon trough shifts northward.

• The monsoon trough is a portion of the Intertropical Convergence Zone (ITCZ) in the Western Pacific showing minimum sea level pressure.

• It is a convergence zone between the wind patterns of the southern and northern hemispheres.

• The core monsoon saw suppressed rainfall and pulled down all-India cumulative monsoon rainfall anomaly from 7% to 6% in less than a month.

• It enhances rainfall along the Himalayan foothills and parts of eastern India while rainfall is suppressed in the rest of the country.

• This happens in the core monsoon zone in areas from Gujarat in the West-to-West Bengal and Odisha in the east, where agricultural activities are rain-fed.

• It is declared based on climatology when the normalized rainfall anomaly index or deviation from the long-term rainfall average over core monsoon zone exceeds and persists for at least three consecutive days.

• The break monsoon ends when the normalized rainfall anomaly decreases in magnitude.

Consequences of end of the monsoon break

• The monsoon trough would shift towards the Himalayan foothills and remain locked until the end of August.

• This will reduce rains in central India once again, so does not indicate a revival of monsoon.

• The monsoonal break from an active phase is normal but can be adverse if it persists for a prolonged period of time.

• It would have an impact on kharif production of paddy, as the government declared a ban on the export of rice.

• The drier western regions in West Rajasthan and Saurashtra-Kutch have received excess rainfall while the usually wetter regions like Kerala, Gangetic West Bengal, Bihar and Jharkhand remained dry due to deficient rainfall.

Factors for a decade-high monsoonal break:

• El Nino: it played a role in prolongation and increased intensity of break monsoon.

• Absence of sub-seasonal weather patterns that boost rainfall.

Instances of Monsoon break

• There have been 10 instances when the break spell has stretched over 10 days in the last 73 years.

• The longest consecutive break spell was in 1972, when the core monsoon zone did not receive any rainfall for 17 days at a stretch.