Peak monsoon showers were pushed to August and September this year from July, said weather officials, who studied the monsoon following its withdrawal from the city.
“During the heavy rainfall period of July, the city received approximately 60% less rainfall. The city witnessed heavy rainfall on only one day in the entire season, when Santacruz recei-ved 185.3mm rainfall on Septe-mber 4,” said VK Rajeev, director, IMD, western region. At the end of September, rainfall deficit at Colaba was 16% and it was 30% in Santacruz.
The delay in peak season rainfall was owing to weak cross-equatorial wind flow. In the cross-equatorial wind flow, winds formed in a high-pressure area in the southern hemisphere flow towards low-pressure areas in the Arabian Sea and the Indian peninsula.
During a healthy monsoon, moisture-laden winds from the Indian Ocean help in cloud formation, resulting in rainfall along the western coast and in the interior.
“The high-pressure area was located away from its usual position, resulting in weak wind flow. These winds are crucial as they pass over the Western Ghats and help in the formation of monsoon clouds. Since their flow was weak, it resulted in below par July rainfall,” said Rajeev.