This winter has been colder, wetter, and largely fogless. Here is why

What is the News?

For many people, especially in North India, the winter of 2021-22 is appearing to be unusually cold and unusually long. The days, in particular, have felt colder and chillier than normal.

What is happening?

Since December 2021, maximum temperatures across the North, Northwest and Central India regions have consistently remained below normal, resulting in “cold day” conditions. 

The India Meteorological Department (IMD) defines a “cold day” as one in which the maximum temperature falls below 16 °C.

“Cold days” often mean warmer nights. Persistent clouding blocks out the rays of the Sun and heating during the day but keeps the nights warmer than normal.

Why is this happening?

Winters over India are directly affected by the intensity and frequency of western disturbances.

Note: Western Disturbances are eastward propagating wind streams, capable of inducing rain or snow-bearing weather systems along their path.

Frequent and higher numbers of western disturbances are associated with La Niña. Until January 26th 2022, seven western disturbances had passed over India. These caused hail storms in northern Maharashtra and heavy rainfall in Tamil Nadu.

Moreover, after a western disturbance crosses India, cold winds from the far north penetrate to lower latitudes, and can reach up to even Telangana and Maharashtra, leading to colder weather, and sometimes to cold wave conditions. 

Since consecutive western disturbances were separated by 10 days earlier this month, it caused a prolonged cold spell in North, Northwest and Central India.

Source: This post is based on the article ‘This winter has been colder, wetter, and largely fogless. Here is why’ published in Indian Express on 27th January 2022.