Delhi/NCR recorded very light and scattered rains yesterday. Nearly half of the observatories registered zero rainfall, and a few recorded just 1-2mm in the evening hours. The airport observatory Palam recorded 5.8mm rainfall, whereas the base station Safdarjung and Lodhi Road Met Office had too little to measure the rainfall. As expected, the day temperature remained below normal by about 2-3°C, under highly humid conditions.
Halfway through the month, Delhi’s record observatory Safdarjung has accumulated 100mm rainfall, as against the normal of 195.8mm for the month of July. The track record of July has been good, wherein out of 15 years since 2010, the capital city has gone above normal on 11 occasions. However, four of them—July 2011, 2012, 2014, and 2017—were below normal, with the least rainfall of 94.8mm in July 2012. On the other side, the remaining 11 years clocked above normal rainfall and mostly exceeded the average by a decent margin. Amongst these years, July 2021 was the rainiest, with a monthly aggregate of 507.1mm. July 2003 holds the record of the highest ever rainfall of 632mm for this month.
The low-pressure area over Rajasthan had earlier strengthened to a depression and has now reverted back to a low-pressure area again. It had moved westward and is lying over Northwest Rajasthan. It is likely to move further northwest and get placed over Northwest Rajasthan, West Punjab, and the border areas of Pakistan in the next 24 hours. Thereafter, the low pressure will weaken and start getting diffused while being stationary over the same region. This is the system controlling the western end of the monsoon trough, which is responsible for weather activity over and around Delhi.
The monsoon trough extends from the center of this system and joins the other circulation of low pressure over the Bihar and Jharkhand region. The elongated east-west trough has shifted northward, a little closer to Delhi. It is expected to run through the capital city tomorrow and the day after. With the low pressure over Rajasthan getting weak and the other low pressure likely shifting closer to the hills of West Uttar Pradesh, the trough will shift far to the north of Delhi on Saturday and Sunday.
Delhi will have light and patchy rainfall today in some areas. The intensity and spread will increase tomorrow and the day after. Sharp showers of moderate intensity are likely on Thursday and Friday, with a better bet on Thursday. Mostly drier weather conditions are expected for the weekend on 19th and 20th July. One odd stray shower in an isolated pocket, due to local heat and humidity, cannot be ruled out. The duration of any such fleeting shower will be just minimal.
