IMD plans 3 more radars in Delhi-NCR to improve forecasting capability

Delhi-NCR will get three more Doppler radars in the next two to three years, along with a flood warning model, additional automatic weather stations and rain gauges to improve weather forecasts, IMD chief Mrutyunjay Mohapatra said on Monday.

According to Mohapatra, the rains that brought Delhi to its knees last week were not a result of a cloudburst but "it was close".
"(Predicting) this kind of very confined activity, both in spatial and temporal terms, is a challenge not only in India but also throughout the world. Prediction becomes easier when you have a large-scale synoptic system," Mohapatra said.

The India Meteorological Department (IMD) has undertaken a project to augment its observational and forecasting capability in Delhi-NCR, similar to what it did in Kolkata, Mumbai, and Chennai. It is also working on a flood warning system for the national capital, he said.

He told PTI, "Three radars of varying radius will be installed in the region in two to three years in addition to the three existing ones." The three functional radars are located at Palam, Ayanagar, and Mausam Bhavan.

Mohapatra said the Safdarjung Observatory, the city's primary weather station, recorded 91 mm of rainfall between 5 am and 6 am on June 28. Similarly, the Lodhi Road weather station logged 64 mm from 5 am to 6 am and 89 mm from 6 am to 7 am.

"These do not warrant being declared as cloudbursts, but it was very close to a cloudburst," Mohapatra said.

According to the IMD, more than 100 mm of rain in one hour over an area of 20-30 square km is called a cloudburst.

"The prolonged heat wave spell in northwest India increased the moisture-holding capacity of the atmosphere, thus increasing the probability of heavy rainfall in Delhi," he added.

Explaining the reason behind the extreme weather event, the IMD had earlier said multiple large-scale monsoonal weather systems created conditions for mesoscale convective activity over Delhi-NCR, resulting in intense thunderstorms and heavy rainfall during the early hours of June 28.

This activity was supported by thermodynamic instability in the atmosphere, which is favourable for thunderstorms.

The Safdarjung Observatory recorded 228.1 mm of rainfall in the 24 hours ending at 8.30 am on Friday, more than three times the June rainfall average of 74.1 mm and the highest for the month in 88 years -- since 1936.

The IMD defines very heavy rain as rainfall amounting to between 124.5 and 244.4 mm in a day.