Mumbai Monsoon Update: Dry Spell Follows Early Onset, Residents Brace for Humid Conditions

Mumbai, 18th June 2024: After an early arrival of the southwest monsoon in Mumbai on June 9, the city has experienced a dry spell over the past week.

Despite receiving nearly 100 mm of rain within the first 24 hours of the monsoon’s onset, rainfall intensity has significantly reduced in the subsequent days, leaving residents coping with humid and sultry conditions.

Data from the BMC reveals that from Sunday to Monday morning, the eastern suburbs received 2.90 mm of rain, followed by 1.28 mm in the Island City division, and 0.76 mm in the western suburbs.

The India Meteorological Department (IMD) forecasts a revival of monsoon activity in Mumbai and its neighboring districts this week. As of Monday, however, the IMD’s Colaba observatory reported no rain, while Santacruz station recorded a minimal drizzle of 0.3 mm. Despite the absence of significant rainfall, maximum temperatures in the suburbs and the city have hovered around 33-34 degrees Celsius.

IMD data indicates that from June 1 to 12, Mumbai city has experienced a rainfall departure of 20% below its long-term average, categorized as ‘deficient’. Meanwhile, Mumbai suburban district has seen a departure of 16% below normal, falling within the ‘normal’ range.

Reasons for the delayed rainfall in Mumbai:
According to senior IMD scientists, the early onset of the southwest monsoon in Mumbai on June 9 was due to favorable atmospheric conditions, including wind patterns and the presence of a shear zone. Normally expected around June 11, the monsoon’s early arrival was noted this year.

However, the shear zone and monsoon currents weakened soon after, leading to reduced rainfall activity.

Sushma Nair, an IMD scientist, explained to The Indian Express that the weakening of westerly winds, which bring moisture and precipitation, contributed to the dry spell. She noted, “The strength of the westerly winds decreased over the past week, resulting in diminished rainfall.”

Rajesh Kapadia from Vagaries of Weather added that the absence of a robust offshore monsoon trough along the Maharashtra coast has also contributed to the lull in rainfall. Additionally, the monsoon access trough, typically present over central India, is expected to form after June 20-21.

Expected revival of rainfall:
Weather experts anticipate an increase in rainfall activity in Mumbai starting from around June 19. Sunil Kamble, IMD Mumbai’s director, indicated that the intensity of rain would depend on forthcoming weather developments in the region. Nair suggested, “Monsoon currents have strengthened significantly, and moderate showers can be expected in Mumbai this week.”

IMD has issued a yellow alert for Wednesday, indicating the likelihood of heavy rain in parts of the district. While no warnings have been issued beyond that, moderate rainfall is anticipated for the remainder of the week.

Looking ahead:
In its long-range forecast for the monsoon season, IMD predicts above-average rainfall for the entire country, including Mumbai. Typically, Mumbai receives an average of 2,300 mm of rainfall during the monsoon season. IMD scientists anticipate that this year’s rainfall in Mumbai is likely to surpass this average.