Why the monsoon's progress has stalled over Maharashtra, Pg15

Key Highlights:

• The Southwest Monsoon has shown sub-nominal performance, with all-India rainfall 38% below average between June 1 and 17.
• The monsoon's advance has stalled over Maharashtra since June 8, leading to a prolonged wait for its onset in the state.
• The Arabian Sea branch of the monsoon is progressing slower compared to the Bay of Bengal branch this year.
• The India Meteorological Department (IMD) has not updated on Maharashtra's monsoon advancement since June 16, indicating uncertainty.

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Detailed Insights:

• The Southwest Monsoon typically brings over 70% of India’s annual rainfall between June and September.
• After its onset over Kerala on June 4, the monsoon advanced into parts of Karnataka and Goa but was delayed in northeast India.
• Weakened monsoonal winds from the Arabian Sea and stronger dry northerly/northwesterly winds are hindering the monsoon's progress over Maharashtra.
• A weakened cross-equatorial wind flow over the western Indian Ocean and Arabian Sea is reducing moisture pumping, further impeding advancement.
• The absence of supporting weather systems like low-pressure areas, cyclonic circulations, or an off-shore trough is contributing to the stall.
• The Madden-Julian Oscillation (MJO) is currently in an unfavorable phase, which is not supporting rainfall over India.
• The IMD forecasts the monsoon to advance next over Telangana, Odisha, Jharkhand, Bihar, and parts of Chhattisgarh in the coming days.

Scientific/Technical Concepts Involved:

• Southwest Monsoon: Seasonal wind system bringing heavy rainfall to India from June to September, crucial for agriculture.
• Madden-Julian Oscillation (MJO): An eastward-moving disturbance of clouds, rainfall, winds, and pressure that traverses the planet in the tropics.
• Low-pressure areas/Cyclonic Circulations: Regions of reduced atmospheric pressure that attract surrounding air, often leading to cloud formation and rainfall.
• Off-shore trough: An elongated area of relatively low atmospheric pressure that runs parallel to the west coast of India, aiding monsoon rainfall.