What fuelled the gusty thunderstorm that struck Delhi-NCR today?

A spell of gusty winds and heavy rainfall swept across parts of Delhi-NCR on THursday, bringing much-needed relief from soaring temperatures but also triggering brief disruptions across the region.

The India Meteorological Department (IMD) had issued a nowcast warning predicting thunderstorms, moderate rain, lightning and gusty winds of 30-50 km/h over several parts of Delhi, including Narela, Alipur, Burari, Badli, Model Town, Karawal Nagar, Azadpur, Delhi University, Civil Lines, Dilshad Garden, Seemapuri, Kashmiri Gate, Shahdara, Vivek Vihar and Red Fort, as well as Loni Dehat in the National Capital Region.

Meteorologists say the storm was fuelled by a combination of intense daytime heating, abundant moisture and favourable upper-air weather conditions.

For the past several days, Delhi-NCR has experienced hot and humid weather, allowing large amounts of heat energy to build up near the surface. As temperatures rose during the day, warm air rapidly ascended into the atmosphere. At the same time, moisture-laden winds from the Arabian Sea and Bay of Bengal provided the humidity needed for cloud formation.

When this warm, moist air rose and encountered cooler air aloft, towering cumulonimbus clouds developed rapidly. These clouds are responsible for severe weather events such as thunderstorms, hailstorms, lightning and strong wind gusts.

The presence of a western disturbance over north India likely enhanced atmospheric instability. Such systems often interact with moist lower-level winds and can trigger intense convective activity across the plains of northwest India, including Delhi-NCR.

The strong downdrafts generated inside thunderstorm clouds were responsible for the sudden gusty winds experienced across many parts of the capital. In some areas, these downdrafts also carried hailstones to the ground as ice particles formed in the upper reaches of the storm clouds.

The rainfall helped lower temperatures significantly and improved comfort levels after days of oppressive heat. However, meteorologists caution that pre-monsoon thunderstorms can be highly localized and intense, bringing risks such as lightning strikes, falling trees and temporary waterlogging.

With the southwest monsoon advancing across parts of India, similar episodes of thunderstorm activity are expected to continue over Delhi-NCR in the coming days, keeping temperatures in check while bringing occasional spells of rain and gusty winds.