The Story So Far: A Deficit Monsoon
The 2026 monsoon season has been a story of sharp contrasts. Despite episodes of intense rain and flooding in some areas, the country as a whole faced a rainfall deficit of around 14% as of early September. The India Meteorological Department (IMD) had
already forecast that September rainfall would likely be below normal, following one of the hottest and driest Augusts on record. This deficit has been particularly pronounced in peninsular, east, and northeast India, raising concerns for agriculture and water reservoirs as the four-month season enters its final and crucial phase. The performance in September is vital, not just for the standing summer crops but also for ensuring adequate soil moisture for the upcoming winter sowing season.
A Glimmer of Hope in the Bay of Bengal
Just as the monsoon seemed to be winding down, especially over southern India, meteorologists have identified a new weather system that could bring a fresh spell of rain. An IMD extended-range forecast indicated that a cyclonic circulation is expected to form over the Bay of Bengal. This is predicted to develop into a low-pressure area over the northwest Bay of Bengal, near the coasts of south Odisha and north Andhra Pradesh, around September 11. Such systems are the primary drivers of monsoon rainfall, and this development has shifted attention to the east coast as a potential source of a much-needed monsoon revival.
How These Weather Systems Work
Low-pressure systems are essentially engines of the monsoon. They are large areas of atmospheric instability where the air pressure is lower than its surroundings. This causes moist air from over the sea to converge and rise. As this air ascends, it cools, and the water vapour within it condenses to form clouds, eventually leading to widespread rainfall. During the monsoon, these systems typically form over the Bay of Bengal and move west-northwest across the Indian subcontinent, delivering rain to the central and northern plains. The strength, duration, and track of these systems determine the distribution and intensity of rainfall. Even in a generally dry month like August 2026, a series of low-pressure systems brought concentrated heavy rains to some regions.
What the Experts Are Forecasting
While it's too early to declare an end to the monsoon's quiet phase, the new system offers some promise. The IMD and other forecasters expect the low-pressure area to increase rainfall over eastern and adjoining central parts of India. Heavy rainfall is anticipated in parts of West Bengal, particularly in the southern districts, leading up to and after the system's formation. Scattered to widespread showers are also predicted for Odisha, Chhattisgarh, and parts of Madhya Pradesh in the coming week. However, the impact might be uneven. While rainfall activity is likely to pick up in the east, peninsular India may continue to experience subdued rainfall for at least another week.
Will It Be Enough to Change the Pattern?
The critical question is whether this single system can meaningfully offset the existing rainfall deficit. The consensus suggests it will bring a welcome spell of rain but may not be a nationwide game-changer. The rainfall is expected to be concentrated over eastern and central India. While this will provide relief to these regions, other areas, especially in the south and northwest, may not see significant benefits. The overall outlook for September, influenced by a strong El Niño, remains one of below-normal rainfall for the country as a whole. This system could help reduce the deficit in specific regions but is unlikely to completely reverse the broader trend of a drier-than-normal end to the 2026 monsoon. The withdrawal of the monsoon, which typically begins from the northwest after mid-September, is also a factor, with conditions expected to become favourable for retreat in the second half of the month.
