Introduction:
The southwest monsoon is currently active across a significant portion of India, with widespread rainfall observed in around 80% of the country. Regions such as Assam, West Bengal, Uttar Pradesh, Uttarakhand, Gujarat, coastal Maharashtra, Karnataka, Kerala, and
Lakshadweep have experienced heavy to extremely heavy rainfall.
The monsoon gained strength towards the end of June, arriving across the entire country six days ahead of schedule.
Body:
Factors influencing the variability of monsoon rainfall in India:
- The monsoon’s intensity and coverage have been supported by multiple weather systems, ensuring consistent rainfall across southern peninsular, eastern, northeastern, and central India.
- Two primary factors have significantly contributed to the increased rainfall:
- Continuous inflow of moisture-laden westerly winds from the Arabian Sea.
- The positioning of the monsoon trough, a semi-permanent low-pressure area extending between Pakistan and the Bay of Bengal during the monsoon season.
- Additional weather systems that have contributed to the widespread rainfall include:
- The persistence of an off-shore trough, a shallow low-pressure area, along the coast from south Gujarat to north Kerala for over a week.
- The intermittent formation of a wind shear zone, where winds at different altitudes move at varying speeds and directions, particularly along the 20°N latitude between central and peninsular India.
- The development of a low-pressure system over the west-central Bay of Bengal, which further enhances rainfall in the region.
Conclusion:
- The southwest monsoon is expected to remain active across the southern peninsula, eastern India, and the Himalayan regions in the coming days.
- The emergence of a low-pressure system over the northwest Bay of Bengal is likely to sustain the monsoon’s momentum, leading to continued rainfall in eastern and central India in the near future.