Maximum dips to 14.2°C, ‘orange alert’ ahead in Delhi

Cold day conditions returned to the Capital after a hiatus ofeight days slashing the maximum temperature down to 14.2 degrees Celsius (°C) — an acute 4.4°C drop from Thursday and five degrees below normal for this time of the year — the India Meteorological Department (IMD) said. It was 18.6°C on Thursday.

With this, frigid daytime feels also returned to the city even as a familiar dense layer of fog shrouded Delhi in the early hours of Friday, throwing transit operations out of gear once again.

IMD has issued an “orange alert” for similar conditions on Saturday and has forecast that a “dense” to “very dense” fog will persist in the early hours of Saturday as well along with a “cold” to “severe cold day” conditions.

Airport officials said that at least 100 flights were delayed, three were cancelled and eight were diverted — seven to Jaipur and one to Hyderabad — due to low visibility, which dipped to 50 metres at 11.30pm at Palam, while railway officials said that 22 trains were delayed by over an hour. The cold day conditions also led to the highest-ever power demand of all winter in Delhi, which was clocked at 5,798 MW at 10.20am. This surpassed last winter’s record of 5,726 MW.

The Capital’s minimum, meanwhile, rose further but stayed below the 10-degree mark — a prerequisite for being qualified as a “cold day” — and was recorded at 7.1°C. It was 6.6°C on Thursday.

The weather agency has also forecast that the maximum will stay around 16°C throughout the weekend while the minimum will stay around 8°C.

IMD qualifies it as a “cold day” when the maximum temperature is 4.5°C or more below normal and the minimum is below 10°C.

According to weather officials, the very dense fog — from around 10.30pm on Thursday to 6am on Friday — resulted in a dogged haze in the upper level, subsequently leading to a sooty daytime atmosphere.

“While the dense fog in the early hours was surface level, the fog dissipated later to form a shallow layer of upper haze and obstructed sunlight. When there is upper-level fog, adequate sunlight cannot reach the surface, thus resulting in a dipping maximum. Likewise, not much heat is lost once the sun sets and the minimum goes up,” said Kuldeep Srivastava, a scientist at the IMD.

IMD classifies fog as “shallow” when visibility is between 500 and 1,000 metres, “moderate” when it is between 200 and 500 metres, “dense” when it is between 50 and 200 metres and “very dense” when it is 50 metres or lower.

Individual weather stations also recorded “cold” to “severe cold day” conditions. Lodhi Road recorded a maximum of 13°C, Mayur Vihar recorded a high of 11.9°C while Gurugram and Faridabad recorded 11.7°C and 10.6°C, respectively. The minimum at all the stations stayed below 10°C.

Srivastava added: “The fog was very dense and affected visibility severely. The visibility oscillated between zero metres and 50m for almost four hours at night.”

Meanwhile, Delhi’s air quality index (AQI) deteriorated slightly and the 24-hour average was logged at 348 (very poor) according to the Central Pollution Control Board’s (CPCB) national bulletin at 4pm. It was 318 (very poor) at the same time on Thursday. According to the Early Warning System for Delhi, the air quality is likely to stay “very poor” throughout the weekend.

“The air quality is likely to remain in ‘very poor’ category from till January 21 and gradually improve to ‘poor’ category on January 22,” said the daily bulletin.

Cold wave to severe cold wave conditions are likely to continue over north India over the next three days, IMD said, also predicting dense to very dense fog to prevail over the region for the next five days. Meanwhile, private weather forecaster Skymet predicted snowfall in hill states from January 26.