Monsoon exit delayed; moderate rains expected in Mumbai this week

India Meteorological Department (IMD) has sounded a Yellow Alert for Thane and Palghar districts on Tuesday, warning of rain and thundershowers. Mumbai, meanwhile, is expected to see moderate rainfall through the week, although no official alert has been issued for the city.

The withdrawal of the monsoon, which usually occurs around 8 October in Mumbai, is projected to be delayed this year.

IMD scientists said rainfall in the city is likely to intensify between October 6 and 8 due to a western disturbance. These eastward-moving, rain-bearing wind systems originate near the Mediterranean region, travelling across Afghanistan and Iran before picking up moisture from the Mediterranean Sea, the Black Sea, the Caspian Sea and the Arabian Sea.

Although they mainly influence north India’s winter weather, western disturbances have in recent decades occurred during summer months as well, affecting a wider geographical range.

In Mumbai, they have contributed to the formation of a monsoon trough – a low-pressure zone stretching from Pakistan to the Bay of Bengal. Its southward shift often brings heavy rainfall to the city.

A senior IMD scientist explained that while the city is currently experiencing sunny and humid weather, cloud cover and rainfall are expected to increase from October 6 onwards as the disturbance dips and supplies moisture to the region. The showers, however, are likely to remain of moderate intensity.