| Chain reaction: Rescue workers carry food and packs of bottled water in Mumbai on Monday. (Reuters)
New Delhi, Aug. 1: Weathermen today explained the continuing rain in Mumbai as a routine active cycle of the monsoon marked by the movement of low pressure areas across the peninsula and moisture-rich winds sweeping in from the Arabian Sea.
The northern suburb of Santa Cruz recorded 210 mm of 24-hour rainfall this morning ' less than one-fourth of the unprecedented 944 mm last Wednesday ' but heavy rains were expected to continue for at least another day, meteorologists said.
“But what we’re seeing today is not in any way unusual,” said Subhash Bhan, director of the Northern Hemisphere Analysis Centre at the Indian Meteorological Department (IMD) here. “It’s typical of an active monsoon phase.”
The entire four-month monsoon season is marked by active and non-active periods. During an active period, depressions or low pressure areas form in the Bay of Bengal and move westwards over the Indian landmass, attracting moisture-bearing winds from the Arabian Sea and bringing rain.
Several low pressure areas may form during each active phase that may last several weeks. As the winds from the Arabian Sea move towards the low pressure area, the regions along their path receive rains.
The Western Ghats also contribute to the heavy rains along the western coast, Bhan said. As the high speed winds strike the mountains, they rise and pump moisture into the atmosphere creating the right conditions for heavy rainfall.
The current spell of rainfall is due to a well-marked low pressure area that was located over central Madhya Pradesh close to Sagar this afternoon. It had originated as a deep depression in the north Bay of Bengal that moved west-northwest to reach the Orissa coast by July 30, crossed over into the peninsula a day later, weakening into a low pressure area as it moved over land.
Rainfall is typically heavy in the southwest sector of such a low pressure area. The IMD has also predicted heavy rainfall over central Maharashtra, Konkan and Goa, and in parts of western Madhya Pradesh, coastal Karnataka and Gujarat tomorrow.
The unprecedented heavy rain over Mumbai last week was due to the combined effect of an earlier low pressure area over Madhya Pradesh and a vortex, a whirling system of winds and moisture in the northern suburbs of the city.
The IMD said it has also spotted a fresh low pressure zone forming in the Bay of Bengal, but it is still too early to say whether it will have any impact on Mumbai.