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Indian Express
5 days ago
- Climate
- Indian Express
Why have rains subsided in Mumbai after a historic early onset?
After experiencing its earliest onset of southwest monsoon in 75 years on May 26, rain activity has subsided considerably in Mumbai. For the past week, Mumbai and its neighbouring districts have only received intermittent spells of scant showers. Making for an atypical May, the city experienced showers as early as May 6, with heatwaves eluding the region. Spurred by heavy spells of pre-monsoon showers and a historic early onset of monsoon, the Colaba weather station recorded its rainiest May for the island city since 1918, at 503.2 mm. The Santacruz station also registered 378.4 mm of rain, marking its wettest May in 25 years. However, since then, monsoon activity has receded considerably. Data from the Indian Meteorological Department (IMD) show that the Santacruz station received only 9.2 mm of rain in the first three days of June. The Colaba station registered only 8.2 mm rainfall, nearly 10 mm below the normal for the period. Typically, Mumbai receives an average of 537 millimetres of rainfall in June, the month it experiences the onset of monsoon. Heavy spells of rain during the monsoon in Mumbai are generally influenced by factors such as strong westerly winds, which usher in moisture and build convection. Weather systems like the monsoon trough or the Somali Jet also play a role. For the record, the monsoon trough is an elongated low-pressure area which extends from the heat low over Pakistan to the Bay of Bengal. It is a semi-permanent feature of monsoon circulation, and its southward movement results in heavy downpours. The Somali jet is the low-level, inter-hemispheric and cross-equatorial flow of air, which moves further into eastern Africa by May, followed by arrival into the Arabian Sea. It reaches the west coast of India in June. The strengthening of the Somali Jet is another factor that contributes to heavy rains. However, currently, none of the systems that trigger monsoon currents are active in the region. 'Presently, there is no active system like strong westerlies, offshore troughs or even a strong Somali Jet, which can lead to heavy rains. Therefore, the city is only experiencing on-and-off showers for the past few days owing to the presence of moisture and onset of monsoon,' said an IMD scientist. Mumbai-based Rajesh Kapadia, who runs the Vagaries of Weather blog, said that the low-pressure area (LPA), which had resulted in heavy showers between May 24 and May 27, has also fizzled out. 'Since this LPA is no longer persisting and we have no other supporting system such as a monsoon trough, we are only passing showers at present,' added Kapadia. According to meteorologists from the weather bureau, the southwest monsoon is characterised by dry and wet spells, which are phases influenced by the presence of active systems. Last year, too, the city experienced a lull in showers in June after an early monsoon onset on June 9. Indicating no immediate revival of heavy showers, the IMD has stated that the city and its neighbouring districts will continue to experience only light showers for the next five days. No alerts have been sounded for the region until at least June 7. 'There is no major system at present which indicates that we will receive heavy showers immediately. We are closely observing our models to forecast the intensifying rains,' said an IMD official. The region could see a revival of active monsoon after June 7. 'The break in monsoon conditions may prevail till at least June 9. However, starting June 7, we can expect some thundershowers in the interiors of Maharashtra. Meanwhile, monsoon may gain strength from June 7 or June 8 onwards as well,' said Kapadia. He added that an unseasonal 'ridge' is prevailing currently, which is the opposite of a trough that is characterised by a low pressure area. However, a trough is expected to develop along the west coast by June 8. The IMD's long-range forecast bulletin has said that the city, as well as most parts of the country, will continue to receive 'above normal' rainfall in June. It will also usher in a dip in temperatures, which will likely remain in the normal to below-normal range.
Hindustan Times
27-05-2025
- Climate
- Hindustan Times
Weather experts says IMD alerts and monsoon onset prediction were both faulty
MUMBAI: On Monday, the city woke up to a heavy downpour that caught it completely off guard as the India Meteorological Department (IMD) had issued a yellow alert, the second mildest in its colour code, for the day. The weather bureau on Sunday had also stated that the onset of the monsoon in Mumbai was expected by Wednesday. IMD maintained the yellow alert for May 26 till 8.30 am when the weather station updates the forecasts. It upgraded it to an orange alert at 9.39 am. Less than three hours later, at 12.30pm, it further upgraded the warning to a red alert, indicating extreme rains. Shubhangi Bhute, director of IMD Mumbai was unavailable for comment. On Monday, the weather alerts also coincided with IMD's Regional Meteorological Centre in Mumbai declaring an early onset of the monsoon, the earliest in the last 35 years in Maharashtra and the last 75 years in Mumbai. 'The rainy season approaches Mumbai from Kerala, as the southwest monsoon progresses on the west coast. Usually it takes at least 10-15 days for the southwest winds to reach Mumbai—however, this year they have come early,' said Sushma Nair, scientist at IMD Mumbai. However, weather experts argued that the doppler radar of IMD showed different synoptic conditions. The scientist added that while there were favourable conditions for the monsoon onset, it was not possible for the winds to travel the west coast in two days. Rajesh Kapadia, author of 'Vagaries of Weather', agreed. 'The current rainfall activity does not meet IMD's criteria for announcing the monsoon,' he said. 'There are several technical criteria, which the current patterns do not fulfil. We are currently experiencing winds from the northwest so the rains will pass in two to three days.' Deoras highlighted that IMD would have waited to declare the monsoon, had the current rainfall activity not occurred. 'For a layperson, the monsoon is generally about the rains, not wind patterns,' he said. 'However, to avoid criticism from people, IMD declares the monsoon onset closest to a rainfall activity.' Added Kapadia, 'Because the city has already received rainfall of over 200 mm, people think it is the monsoon already so the weather station has declared it as such.' Both weather experts said the current rain spell would subside over the next two days, leading to dry weather once again. IMD has maintained a yellow alert till Thursday.
Time of India
22-04-2025
- Climate
- Time of India
Maha sees record April temperatures, city logs season's hottest day at 43.2°C
Pune: It's just April, but intense heat has already set in, with Lohegaon recording its hottest day of the season at 43.2°C on Tuesday, while Shivajinagar's temperature too hit 41.2°C, tying its second-highest April temperature, a mark it previously reached on April 16. Tired of too many ads? go ad free now Across Maharashtra, Chandrapur in Vidarbha continued its reign as hottest spot, with the mercury climbing to 45.8°C on Tuesday, up from Monday's 45.6°C. The Vidarbha region remained a virtual furnace with Brahmapuri recording 45.2°C, followed by Akola (44.8°C) and Amravati (44.4°C). "The highest day temperature for the season in Shivajinagar remains 41.3°C, recorded on April 8 this year, indicating that the summer of 2025 is turning out to be particularly harsh, " an expert from the blog, Vagaries of Weather, said. According to IMD, Lohegaon's maximum temperature at 43.2°C was 5 degrees above normal on Tuesday, while Shivajinagar's was 3 degrees higher than normal. Other parts of Maharashtra also witnessed soaring temperatures with Jalgaon and Malegaon both recording 42.8°C, Solapur hitting 43.4°C and Dharashiv reaching 42.5°C. Even coastal areas offered little respite, with Mumbai (Colaba) registering 33.9°C. "The past few days have been unbearable. I've lived in Pune for over 30 years and this April seems to be one of the hottest," Kothrud resident Sunita Deshmukh said, adding, "My power bill has doubled due to constant airconditioner use." Working professional Rahul Kalra, who recently moved to Pune, said, "I am shocked at the intensity of the heat. I was told Pune was pleasant year-round. This feels more like Delhi's summer." IMD-Pune scientist SD Sanap said "There's an anticyclonic circulation over most of Maharashtra, which is causing subsidence of air from upper levels of the atmosphere. Tired of too many ads? go ad free now This compression leads to heating and suppresses cloud formation, resulting in clear skies and intense solar radiation reaching the surface." He said, "We are also seeing northwesterly winds, but they don't have that much effect currently. The weather conditions are expected to remain the same as the anticyclonic circulation is likely to persist for the next few days." Independent weather expert Abhijit Modak told TOI, "The re-emergence of dry air from the north/northwest desert regions is causing another increase in temperatures. Besides, local geographical factors are contributing to it too, specifically in the northeastern suburbs of Pune." Across India, Odisha's Jharsuguda emerged as the hottest location on Tuesday with 46.2°C, followed by Chandrapur, Sambalpur (44.6°C) and Dhenkanal (44.7°C) in Odisha, along with Ratlam (44°C) in Madhya Pradesh. Health authorities have advised people to stay hydrated and avoid outdoor activities during peak afternoon hours.
