Mumbai: The India Meteorological Department (IMD) on Tuesday upgraded the city’s weather warning from a ‘yellow’ alert, indicating ‘heavy to very heavy rain at isolated places to an ‘orange’ alert till July 9, indicating very likely chances of ‘heavy to very heavy rain at isolated places’.
Official forecasts also warned that some isolated locations may receive “extremely heavy rain”, in excess of 200mm in a single day. However, experts and officials also pointed out that rains will decrease in intensity for a short period between July 6 and July 7, picking up once again around July 8, when a fresh low-pressure area is expected to form in the Bay of Bengal.
“There may be a little relief over the next two days, but out of an abundance of caution, we have sounded an orange category alarm so that civic and disaster relief authorities remain on standby in case any evacuation or other interventions are required. It is advised for everyone to check the local conditions before venturing out in rough weather,” said KS Hosalikar, head of the IMD’s surface instrument division in Pune.
As forecasted, Tuesday saw intense downpours across the city, with the IMD’s base weather station in Santacruz recording 124.2mm of rain in just eight hours, between 8.30am and 5.30pm (as opposed to 21mm in the preceding 24 hours), while the coastal station of Colaba received 117.4mm of rain in the same period (as against 13mm in the 24 hours prior). During the subsequent eight hours ending 5.30pm Monday, Santacruz received 153.3mm of rain while Colaba received 48.6mm of rain. Rainfall between 64.5 mm and 115.5 mm in 24 hours is considered ‘heavy’ and between 115.6 and 204.4 is ‘very heavy’. Over 204.5 mm is extremely heavy rain, and over 300 mm is exceptionally heavy rain.
In fact, Tuesday’s downpours were enough to finally balance out the city’s monsoon deficit, which stood at 47% on June 23, as reported by Hindustan Times. However, with a total seasonal rainfall of 885.8mm since June 1 (as of 5:30pm Tuesday), Mumbai’s base weather station has recorded 22% more rain than the normal 720mm, up to July 5.
Not just Mumbai, but the entire Konkan coast was battered with rain on Tuesday, under the impact of four major synoptic developments. “One, there is a low-pressure area which has entered somewhere in Madhya Pradesh, which has strengthened an offshore monsoon trough running from coastal Gujarat to coastal Maharashtra. The trough is south of its normal position which puts the entire Konkan in a favourable spot to receive rain. And lastly, there is a huge surge in westerly winds which are carrying moisture from over the sea and dumping it onto the west coast,” said Jayanta Sarkar, head of the IMD’s regional Mumbai centre.
Maharashtra made up its rainfall deficit for the season, clocking in 227.9mm of rain as against the normal 260mm, averaged across all meteorological sub-divisions.
Lanja in Ratnagiri district recorded exceptionally heavy rainfall as of Tuesday afternoon, at 342mm in 24 hours. Several other parts of the Konkan received heavy to extreme rainfall as of early Tuesday, including Palghar (118mm), Talasari (119mm), Mahad (188mm), Mangaon (230mm), Tala (245mm), Panvel (172.2mm), Ambernath (188mm) and Kalyan (194mm). Officials pointed out that the intensity of rain picked up after 8.30pm on Monday, and that most of the intense showers had taken place during the night, averting greater public inconvenience.
Another monsoon surge is expected over the Konkan, as another low-pressure area will form over the Bay of Bengal around July 8. As a result of the effect this will have on wind patterns, heavy to very heavyvrains are likely in Mumbai. “Following a heavy downpour on July 5, Mumbai-MMR will get a breather on July 6 and 7, as the rainfall intensity as well as accumulation would reduce to a light to moderate category. The local authorities must utilise this window to prepare for the next enhanced rain spell from 8 July, which could extend into early next week,” said Akshay Deoras, an independent meteorologist and researcher with the University of Reading, UK, who actively tracks the southwest monsoon.
Rainfall over 24 hours ending 8.30am Tuesday
Lanja in Ratnagiri district recorded exceptionally heavy rainfall: 342mm
Several other parts of the Konkan received heavy to extremely rainfall:
Palghar (118mm)
Talasari (119mm)
Mahad (188mm)
Mangaon (230mm)
Tala (245mm)
Panvel (172.2mm)
Ambernath (188mm)
Kalyan (194mm)