1,502mm of rainfall in city in July, highest since the readings began

MUMBAI: The month of July ended with the city recording 1,502.7mm rain, the highest for the month since the readings started being collated by the weather bureau (1944).

The city has so far recorded 84% of its average seasonal rainfall. However, deficient rain in catchment areas continued to be a concern. The first week of August, however, could change this as the weather bureau issued an orange alert (heavy to very heavy rain) for Monday and Tuesday and yellow alert (heavy rain) for Sunday. No alert has been issued for Saturday.

The India Meteorological Department (IMD) said July was also marked by a rare occurrence — the absence of a low pressure (LP) weather system formed either over the Arabian Sea (AS) or Bay of Bengal (BOB).

The LP system is a region of lower or reduced atmospheric pressure than normal, causing weather disturbances including increased precipitation and cloud formation.

“These low pressure systems are crucial for maintaining active monsoon conditions over central India, which witnessed deficit rain in July. The BOB was unusually quiet and thus country-wide rain was below expectation,” said M Rajeevan, secretary, Union earth sciences ministry.

“However, Mumbai’s performance was exceptional with the formation of smaller weather systems that ensured good rainfall.”

Mrutyunjay Mohapatra, director-general, IMD, said, “Factors such as offshore trough, embedded vortex (localised circulation) and a mid-tropospheric cyclonic system over Gujarat region during different intervals in July led to this performance.”

Independent meteorologists had a different view.

“While no monsoon depression had a genesis over the BOB, AS or adjoining land areas, two LP circulations were observed over BOB and adjoining areas (around July 5 and July 14) and three others over AS (July 2, 9 and 17). The systems had strength equivalent to at least monsoon LP areas,” said Akshay Deoras, independent meteorologist and PHD researcher at the University of Reading, the United Kingdom.

Mohapatra added that a latest LP system over BOB was expected to form over the next couple of days leading to heavy to very heavy rain for Mumbai and west coast between August 4 and 6.

THE CITY HAS SO FAR RECORDED 84% OF ITS AVERAGE SEASONAL RAINFALL

ELGAR PARISHAD CASE