The Southwest Monsoon has made an early and unexpected entrance into Mumbai, catching residents and officials off guard. The India Meteorological Department (IMD) has responded swiftly, issuing a yellow alert alongside a thunderstorm warning, forecasting moderate to heavy rainfall throughout the day.
“Thunderstorms accompanied by lightning and heavy spells of rain with gusty winds reaching between 62 to 87 kmph are very likely to occur at isolated places in the districts of Mumbai, Thane, and Raigad during the next 3-4 hours,” stated the IMD in a post on social media platform X.
Historically, such an early onset of monsoon is a rare occurrence. Last year, both Delhi and Mumbai experienced the primary rain-bearing system’s arrival on June 25—the first time since June 21, 1961—largely due to Cyclone Biparjoy impacting the southern and adjoining western and central regions of India. Under normal circumstances, the monsoon reaches Kerala by June 1, Mumbai by June 11, and the national capital by June 27. However, on May 15, the weather office announced that the monsoon would hit Kerala by May 31.
In recent developments, weather scientists credit cyclone Remal, which wreaked havoc in West Bengal and Bangladesh at the end of May, for redirecting the monsoon flow towards the Bay of Bengal, precipitating its early onset in the northeast. Such simultaneous monsoon onsets over Kerala and the northeast are quite rare, having previously occurred in 2017, 1997, 1995, and 1991.
The IMD also provides historical context on the monsoon’s behavior. From 1971 to 2024, the earliest onset over Kerala was recorded in 1990 when the southwestern coast saw the first monsoon rains on May 18. Similar early instances occurred on May 22 in 1999 and May 23 in 1974 and 2009.
The weather department’s forecast remains optimistic about the overall monsoon performance this year. In a press conference at the end of May, the IMD maintained its April prediction, anticipating above-normal rainfall for the country during the four-month monsoon season stretching from June to September. The cumulative rainfall is expected to be 106 percent of the long-period average of 87 cm.
However, regional variations are expected.
. Northeast India is predicted to experience below-normal rainfall, while normal patterns are anticipated in the northwest. Central and southern peninsular regions of the country are likely to receive above-normal rainfall. India’s core monsoon zone, encompassing most of the vital rain-fed agricultural areas, is expected to enjoy an abundance of rainfall this season, according to the IMD.
Monsoon rains are crucial for India’s agricultural landscape. An estimated 52 percent of the country’s net cultivated area relies on these seasonal rains. Beyond agriculture, the monsoon plays a critical role in replenishing water reservoirs essential for drinking water and power generation across the country. June and July are especially significant for agriculture since most sowing for the Kharif crop, a primary seasonal crop, takes place during these months.
Furthermore, the presence of El Nino conditions raises concerns. El Nino, a periodic warming of surface waters in the central Pacific Ocean, is often linked to weaker monsoon winds and drier conditions in India. In contrast, La Nina—considered the opposite of El Nino—tends to bring plentiful monsoon rains. Scientists speculate that La Nina conditions may set in by August-September, bringing hope for sustained rainfall throughout the latter part of the monsoon season.
Given these dynamics, it is vital to monitor how these early monsoon patterns develop. The agricultural sector and water management authorities are especially on alert, considering the potential implications for crop yields and water reservoirs. The government’s preparedness and response will be critical in managing the challenges and opportunities presented by this unusual monsoon season.
Residents in the yellow alert areas are advised to stay updated with the latest weather reports and take necessary precautions to stay safe during this period of unpredictable weather. The IMD continues to monitor the situation closely and will provide updates as needed.
