The Monsoon's September Pause
After a season of erratic behaviour, the southwest monsoon has gone quiet, particularly over Peninsular India. The India Meteorological Department (IMD) has noted that rainfall activity is likely to remain subdued in the southern peninsula for about a week.
This easing of rains is visible, with recent satellite imagery showing significantly reduced cloud cover over northwest and central regions. However, this is not the official end of the season. Forecasters are clear that this is a temporary lull, not a formal withdrawal, which typically begins from the northwest around the middle of September. This year, the full retreat might only get organized around September 21. The current break in the rain comes after a season that has seen a nationwide deficit of around 14% as of early September.
Activity Brewing in the Bay of Bengal
While some regions experience a dry spell, all eyes are turning towards the east. The IMD has forecast the formation of a fresh low-pressure area over the northwest Bay of Bengal, near the coasts of south Odisha and north Andhra Pradesh. This system is expected to take shape around September 11. The development of such low-pressure systems is a common feature of the late monsoon period. These systems are crucial as they draw in moisture and can reinvigorate rainfall, often moving from east to west across the country. The Bangladesh Meteorological Department has also forecast the formation of one to three such low-pressure systems in the Bay of Bengal during September.
Which States Should Brace for Rain?
The developing system is set to shift the focus of heavy rainfall towards India's eastern and northeastern states. The IMD has issued alerts for heavy rainfall in West Bengal, with districts like Purba Bardhaman, Hooghly, Bankura, and the Medinpurs likely to be affected. Odisha is also on alert, with rainfall expected to pick up from September 10. The wet spell is predicted to extend to Chhattisgarh between September 8 and 12. Further east, the northeastern states, including Arunachal Pradesh, Assam, and Meghalaya, are also expected to receive widespread showers through September 13. In contrast, while states like Uttar Pradesh and Uttarakhand have seen rain from a separate system, and areas like Konkan and Goa will continue to see showers, much of the southern peninsula will remain relatively dry.
The Bigger Picture for a Deficit Season
This tale of two weather patterns—a lull in one area and intensification in another—is characteristic of a monsoon influenced by a strong El Niño, which tends to cause drier conditions. The monsoon season has been deficient overall, with rainfall 39% below normal on September 7 alone. The performance of these late-season low-pressure systems is critical. September rainfall is vital for maturing summer-sown crops and ensuring adequate soil moisture for the upcoming winter planting season, which includes major crops like wheat and rapeseed. A prolonged dry spell can impact agricultural yields and rural incomes. Therefore, the trajectory and intensity of the brewing system in the Bay of Bengal are being watched closely, as it holds the potential to either alleviate or worsen the existing rainfall deficit in the regions it crosses.
