Experts blame converging weather systems for May 25 thundershowers in Delhi

The systems in play included a western disturbance, which extended as an upper air cyclonic circulation over north Punjab and adjoining Jammu and Kashmir, with a trough aloft in the mid and upper troposphere\

The city was lashed by another intense storm late Saturday night, the fourth such event to batter the Capital this month. While thunderstorms aren’t out of the ordinary during the pre-monsoon period, however, this year’s May has turned out to be the wettest on record—a result of an unusual confluence of weather systems and ample moisture.

A waterlogged road in southwest Delhi. (Vipin Kumar/HT Photo)

“This time, easterly and southeasterly moisture-laden winds from the Bay of Bengal and southwesterlies from the Arabian Sea converged in the lower troposphere over northwest India,” an IMD scientist said, stating this was aided and intensified by three prevailing weather systems.

“Their interaction with mid-level dry northerlies and northwesterlies typically triggers intense thunderstorm activity. These processes were further enhanced due to a series of weather systems present over the region.”

The systems in play included a western disturbance, which extended as an upper air cyclonic circulation over north Punjab and adjoining Jammu and Kashmir, with a trough aloft in the mid and upper troposphere. Additionally, upper air cyclonic circulations were seen over northwest Uttar Pradesh and adjoining north Haryana, as well as over West Rajasthan. “The interaction of all these systems led to the intense event on Sunday,” the IMD official added.

These storms, often marked by fierce winds and lashing rain, have left a deadly toll in their wake — 12 lives lost this month alone, with damage caused by uprooted trees, collapsed walls, and fallen poles. The month’s squally events struck on May 2nd, 17th, 21st and now 25th, with the winds on Sunday peaking at 82 km/hr at Safdarjung, Delhi’s base weather station.

On May 15 as well, a dust storm swept through the city, its winds touching 40 km/hr, fouling the air but bringing no rainfall. The air remained covered in a haze of dust for nearly 12 hours.

According to IMD chief Mrutyunjay Mohapatra, while thunderstorms in May aren’t new, this year’s spike in frequency and intensity stands out. “The frequency of western disturbances has been quite high this month, influencing a large part of the northern and eastern states,” he said.

“Summer thunderstorms need high temperatures, humidity, winds, and a triggering system — in this case, the western disturbance. All these have aligned this season, and if this continues, it could be a sign of climate change,” he said.

As the western disturbance moved east, interacting with strong easterlies, it first struck north Punjab, then rolled into Delhi-NCR via Haryana, according to weatherman Navdeep Dahiya. “The Western Disturbance began interacting with strong easterlies and this led to a widespread storm formation..” he posted on X.

Forecasts show on-and-off thunderstorm activity is expected to continue this week, with chances of light rain.