The Indian Meteorological Department (IMD), which is facing criticism over errors in several forecasts on the advance of southwest monsoon over Delhi, said on Monday that such failure by numerical models in predicting the advance of monsoon in the capital. is 'rare and unusual.
The Meteorological Department said its latest model analysis indicated that low-lying moist easterly winds from the Bay of Bengal would spread over northwest India covering Punjab and Haryana by July 10, allowing the monsoon to advance further from July 10. Rain activities will increase over this region including Delhi.
Accordingly, moist easterly winds have spread over northwest India, the IMD said in a statement. The IMD said that these moist winds have led to cloud cover and an increase in relative humidity. Due to this, the monsoon has resumed in the region and very widespread or widespread rainfall has occurred over East Rajasthan, Himachal Pradesh, Uttarakhand, Jammu, and Kashmir and isolated rains over Punjab and West Rajasthan.
"However, it did not cause significant rainfall in Delhi, even though the neighboring places around Delhi received rainfall," the IMD said. The desert districts of Ganganagar and Jaisalmer also received rainfall and Delhi did not, the IMD said. "Such failure of numerical models in predicting the advance of monsoon over Delhi is rare and unusual," it said.
It is needless to mention that the IMD has given high accuracy about the advance of monsoon over Delhi in recent years and about four to five days in advance about monsoon advance over different parts of the country during Monsoon 2021, it said. With good predictions.'
The IMD had said on June 13 that the southwest monsoon would reach the national capital by June 15. The IMD said that after the onset of Monsoon over Kerala on June 3, Monsoon continued to advance over the country till June 13 with favorable atmospheric circulation and a low-pressure system over the Bay of Bengal. By June 13, it had covered most parts of the country except northwest India.
The Numerical Weather Prediction (NWP) model indicated favorable conditions with moist low-level easterly winds over northwest India on June 13, leading to the onset of monsoon over most parts of Madhya Pradesh, remaining parts of Uttar Pradesh, in the subsequent 48 hours. It would have helped to move forward in Delhi, Haryana, and Punjab.
Accordingly, a press release was issued on June 13 indicating the likely arrival of monsoon over Delhi by June 15, the IMD said. However, on June 14, weather analysis based on satellite and NWP models gave an answer- Weakening of easterly winds was indicated over West India. It issued an updated press release on June 14 indicating that the further advance of Southwest Monsoon into the remaining parts of Northwest India, including Delhi, would be slow and delayed.