Delhi is not a coastal area, so people must not expect heavy rains in Delhi, he explained.
Delhi and the surrounding capital region will see patchy rains for the next three to four days with light showers, RK Jenamani, a senior scientist at the weather department, said today. On getting the Delhi rains forecasts wrong this time, he said 100 per cent accuracy in the prediction of localised rainfall is difficult for any country. The India Meteorological Department's (IMD) forecast accuracy of Delhi rains is about 80 per cent, he added.
He said Delhi will continue to be humid but can expect rains in the next couple of days. Light showers are expected in Delhi on July 12 or 13 but there's no clarity about the intensity yet. He claimed Delhi will receive normal rainfall this year, and will not be negative as is being speculated by some.
"Delhi has intense heat and sources of moisture are limited. It's also very far from the seas and is landlocked. So, rains are dependent on a lot of factors. When clouds gather, it's a challenge to ascertain whether it will rain in Delhi, Mathura, Agra, or Haryana," he said, adding that local factors like urbanisation also modify rain distribution, hence the delay.
Speaking to NDTV, Mr Jenamani said the IMD's forecast accuracy has improved by over 30 per cent in the past five years but it still has many gap areas so the forecast cannot yet be 100 per cent accurate.
"IMD is working towards minimising wrong forecasts," he said, adding that the weather office has started putting up high-resolution weather radars in light of the wrong forecasts. It is also increasing the number of observational systems and working towards changing their forecast modelling systems to minimise errors.
"We are expecting the monsoon trough to move towards the north in the next two days, it has been to the south of Delhi, hence the scattered rains," he said.
Mr Jenamani also pointed out that the arrival of the monsoon does not mean it will rain heavily every day. Delhi is not a coastal area, so people must not expect heavy rains in Delhi, he said.
Delhi, Punjab, Haryana, and Chandigarh will receive normal rainfall but eastern states like Bihar, Jharkhand, West Bengal, and eastern Uttar Pradesh will receive "negative rain" (i.e. deficient rainfall levels), he said.
He also stressed that the media should highlight areas like Gujarat, Mumbai, Vidarbha, and Telangana, where severe weather has been predicted.
"Delhi can be focussed on, but it shouldn't be the only focus," he said.
As of 2:45 pm, the IMD forecast for monsoon rain in the next two hours predicts thunderstorms with moderate to heavy intensity rain would occur over and adjoining areas of many places of Delhi and NCR (Hindon AF Station, Indirapuram, Noida, Gurugram, Manesar) Rohtak, Kharkhoda, Charkhi Dadri, Mattanhail, Jhajjar, Farukhnagar, Kosali, Rewari (Haryana) Dadri, Deoband, Shamli, Khatauli, Jalesar (U.P.) Bhiwari, Alwar, Tizara, Nagar, Deeg, Laxmangarh (Rajasthan).