‘Monsoon to hit Delhi well before schedule’
NEW DELHI: The south-west monsoon is set to reach Delhi and most of north-west India by June 15, almost a fortnight ahead of schedule, due to a low pressure system building up over the Bay of Bengal, the India Meteorological Department (IMD) said on Friday.
The Met’s forecast also said that pre-monsoon showers are expected to start in the Capital from Saturday, and intensify on Sunday and Monday. This, weather analysts said, will lead to moderate to heavy rainfall, hail and thunderstorms, and bring down day temperatures in parts of the city to around 34 degrees Celsius.
Some parts of Delhi got light rain and dust storms late on Thursday and early on Friday morning.
The monsoon usually arrives in Delhi by June 27-28, and Kuldeep Srivastava, the head of IMD’S regional weather forecasting centre, said it was set to advance swiftly this year due to weather conditions in the northern Bay of Bengal. “The reason behind this sudden advancement is the formation of a low-pressure system over northern Bay of Bengal. When a low-pressure area is formed at the onset of monsoon, it creates conditions conducive for the advancement of monsoon.”
He said that, except for some parts of Rajasthan and Gujarat, the monsoon is likely to cover all of north-west India by June 15.
HT reported on Friday that the monsoon was racing across the country after arriving two days late in Kerala, and was likely to cover the entire country a fortnight ahead of the usual July 8 date under favourable conditions.
Mahesh Palawat, vice-president, Skymet Weather Services, also said that the monsoon was likely to arrive by next week in Delhi. “A trough has formed over Punjab, Haryana, Delhi, Uttar Pradesh, covering Odisha and the monsoon activity will move along this trough. On Saturday, Delhi will start receiving patchy rain, and by Sunday and Monday, it will intensify.”
He added that while premonsoon showers are usually thundery, monsoon showers are characterised by uniform rain, and the transition is likely by Tuesday. “We can foretell monsoon arrival by patchy rain, increase in humidity, and persistent cloudiness.”
“Monsoon has been very active this year right from the onset. The westerly and southwesterly winds are very strong over the Arabian Sea, and a low pressure area over the Bay of Bengal is now pulling the monsoon flow. Both branches on the Arabian Sea and Bay of Bengal side are supporting the advancement of monsoon over the country, except in dry regions of Rajasthan and Kutch,” said RK Jenamani, senior scientist, national weather forecasting centre.
Weather analysts said that the monsoon’s progress over the entire country has advanced in recent years. “We issued new monsoon onset and withdrawal dates last year after we noticed that monsoon dates had advanced in some parts while it was delayed in others due to many factors, including global climate change. The thresholds have changed,” said M Rajeevan, secretary, Union ministry of earth sciences.
“For example, the new onset dates are delayed by three to seven days in many parts of central, west and east India, while the complete coverage of monsoon in the country has advanced. This year is exceptional because monsoon has covered parts of central India very early. Monsoon covered the entire country by June-end in the past also, but this year, its trajectory is exceptional,” he added.
DS Pai, scientist and head of climate research services at IMD Pune, concurred.
“Last year as well, the monsoon covered the entire country by around June 26, so it’s not rare. The movement of monsoon depends on how early a low pressure system forms. Its active progress will sustain till the low pressure system sustains and then monsoon progress may weaken temporarily. In recent years monsoon onset dates have advanced because of a change in its pattern,” Pai said.
The weather pattern since August 2020 has thrown up a surprise and broken a historical record every single month -either by being hotter, wetter, or colder than usual. This, for example, is likely to be the first June on record to not get a single heatwave day, with rain expected to bring down the temperature further.
Met officials and scientists said that while the extreme weather recordings were the result of temporary atmospheric events in and around the national capital, the larger role of the climate crisis in the overall shifting of weather patterns was evident as well.