Delhi sees highest 24-hour rainfall for Jan since 1999

The Safdarjung weather observatory, which provides representative figures for the city, recorded 40.6 mm of rainfall in 24 hours between 8.30 am on Friday and 8.30 am on Saturday. Most of this rainfall was recorded in the early hours of Saturday. This is the highest 24-hour rainfall recorded in the past 22 years in January, according to scientists at the IMD.

The rainfall recorded on Saturday came second to the 46 mm of rainfall recorded on January 7, 1999. The highest 24-hour rainfall recorded in January last year was only 25.1 mm, while it was 16.8 mm in January 2020.

Meanwhile, the Palam station recorded 47.6 mm of rainfall between 8.30 am on Friday and 8.30 am on Saturday, making it the highest 24-hour rainfall in January in the past 27 years at the observatory. In the same time frame, the observatory at the Ridge recorded 48 mm, Aya Nagar 49 mm, and Lodhi Road 42.2 mm.

The IMD had predicted a wet spell over northwest India till January 9, on account of a western disturbance lying over north Pakistan and surrounding areas, and an induced cyclonic circulation over east Rajasthan and the neighbourhood induced by the western disturbance.

Western disturbances originate over the Mediterranean Sea, Caspian Sea or Black Sea, and eastwards across North India, bringing winter rainfall, according to the IMD.

“This was an intense system and the season’s most active western disturbance. The rainfall depends on the moisture picked up from the Arabian Sea, and it picked up fresh moisture after coming over to the India and Pakistan region. If it was further north, it would not have picked up moisture from the sea,” said R K Jenamani, senior scientist, IMD.

Cloudy skies and light rainfall remain on the forecast for Sunday as well.

The rainfall brought with it an improvement in the air quality. The AQI on Saturday was 91, in the ‘satisfactory’ category. This is the first such ‘satisfactory’ air day since October, when October 25 recorded AQI in the ‘satisfactory’ range.

From January 1 to 8, the capital had witnessed one ‘severe’ air day. Going by the Air Quality Early Warning System for Delhi, the AQI is likely to be in the ‘moderate’ category on Sunday.

The minimum temperature, at 15.2 degree Celsius, was eight degrees above the normal for this time of the year while the maximum temperature was 16.4 degree Celsius, three degrees below normal.

There was little difference between the minimum temperature, usually recorded at night, and the maximum temperature that is usually registered in the day. This was also on account of the western disturbance, and the associated moisture levels, clouds and wind, according to IMD scientists.