Rain lashes parts of Capital but July continues in deficit

Met officials said Monday’s rain was also aided by high temperature during the day and the incursion of moisture from a western disturbance in northwest India.

Parts of Delhi on Monday afternoon recorded short but intense spells of rain, leading to waterlogging that triggered traffic snarls on several arterial roads.

A view of Kartavya Path during heavy rain in New Delhi on Monday. (ANI Photo)

India Meteorological Department (IMD) officials said on Monday, light to moderate rainfall was logged in west, central, north, and southwest Delhi. The Safdarjung observatory, representative of Delhi’s weather, received 31.4mm of rainfall between 8.30 am and 5.30 pm on Monday.

However, the rain failed to cover the deficit that Delhi currently faces for July.

“This has been a particularly hot and humid July, characterised by calm winds and high humidity. For most of the month, the monsoon trough has stayed south of Delhi and closer to central India, which is why we are not seeing any significant rain,” said Mahesh Palawat, vice president at Skymet, adding that every time the trough moves closer to Delhi — as it did on Monday — Delhi logs an increase in rain intensity.

Met officials said Monday’s rain was also aided by high temperature during the day and the incursion of moisture from a western disturbance in northwest India.

“We saw convection and the formation of thunderclouds, which was due to a combination of factors which included the monsoon trough moving closer to Delhi, moisture coming from a western disturbance and high temperature before noon. This led to quick formation of rain clouds across Delhi-NCR and moderate rainfall was recorded in some parts of the city, particularly north and west Delhi,” said an IMD official, stating there were chances of similar rain occurring on Tuesday and Wednesday.

IMD data showed that after Monday’s spell, Delhi’s monthly rainfall total for July is now 118.2mm, but this is far short of the average of 143.4mm normally recorded till July 21. This means Delhi is still in deficit this month and will require one to two spells of moderate rain to bridge this gap.

The normal monthly average for rainfall in July is 209.7mm, and last year, Delhi recorded 384.6mm of rainfall.

IMD classifies rainfall as “very light” when it is below 2.4mm in 24 hours; as “light” when it is between 2.5 and 15.5mm; as “moderate” when it is between 15.6mm and 64.4mm; as “heavy” when it is between 64.5mm and 115.5mm, and “very heavy” when it is over 115.6mm.

Out of the 12 rainy days so far this month, Delhi has recorded very light to light rainfall on 10 occasions, making Monday only the second “moderate” rainfall spell for this month.

Delhi has not recorded any “heavy” rainfall day since June 28.

Traffic chaos

On Monday, the weather station at Pusa in west Delhi logged the highest amount of rain at 53mm. This was followed by Pitampura (49mm), Delhi University (40mm), Ridge (27.8mm), Lodhi Road (26.6mm) and Najafgarh (24mm).

The rain led to waterlogging in parts of the city, forcing the Delhi Traffic Police to issue advisories, warning people of congestion on GT Road in northeast Delhi, Firni Road at Najafgarh, and New Rohtak Road in west Delhi, asking commuters to avoid these routes.

Ashish Verma, 33, who was headed from Lajpat Nagar to Jahangirpuri on Monday afternoon, said he faced waterlogging near ITO, and at Delhi University. “It took me well over an hour to cross these stretches. Traffic was slowing down due to water accumulated on the road,” he said.

Mercury down

Despite the rain, Delhi’s temperature continued to remain high on Monday. The Capital logged a maximum temperature of 36.4°C, a notch above normal. It was 36.6°C a day earlier.

Monday’s relative humidity oscillated between 65-100% during the day, but the city also recorded winds of 10-15 kmph, IMD said.

The air temperature at Safdarjung was 35.8°C at 11:30 am, with relative humidity at 65%. This gave Delhi a heat index (HI) or “real feel” of 50°C. However, parts of Delhi began to see rain from noon onwards, with the temperature recorded at 2.30 pm as 27.6°C. The “real feel” had dropped to 35°C.

Delhi’s wet bulb temperature, another indicator of thermal discomfort, was 30°C at 11.30 am, but dropped to 27.6°C at 2.30 pm, aided by rain and good wind speed. A wet bulb temperature of 32°C or higher makes it difficult for even fit and acclimatised people to work outdoors for long, and at a wet bulb temperature of 35°C — the maximum threshold — humans can no longer regulate body temperatures, leading to heatstroke and potential collapse.

Meanwhile, the minimum for the day was 29.4°C, which was two degrees above normal. It was 26.4°C a day earlier. Forecasts show Delhi’s maximum should hover between 34-35°C till Wednesday, while the minimum should hover close to 27°C.

In terms of air quality, Delhi’s air was back in the ‘satisfactory’ category, recording a 24-hour average air quality index (AQI) reading of 85 on Monday. In comparison, it was 103 (moderate) on Sunday.