Environment

Why is Delhi going through an extra cold December?

At 3.7 degrees Celsius, Delhi has already recorded its coldest December morning in the last 12 years; the IMD predicts that in coming days the temperature can fall

 
Last Updated: Thursday 27 December 2018

Why is Delhi going through an extra cold December?  At 3.7 degrees Celsius, Delhi has already recorded its coldest December morning in the last 12 years.

The India Meteorological Department (IMD) predicts that in coming days the temperature can fall below 3 degrees Celsius. The minimum temperature on December 28 could go down to 2.6 degrees Celsius.

The last time Delhi hit a such a low minimum temperature was on December 29, 2007, when the capital logged 3.9 degrees Celsius.

This dip is attributed to cold wave conditions prevailing over north-west India.

Cold wave conditions form due to lack of western disturbances.

Western disturbances are extra-tropical storms that mostly appear during the winter months. They are called extra-tropical storms because they orginate outside the tropics. They originate somewhere near the meditarian sea and the Atlantic Ocean and are laden with moisture. Western disturbances create precipitation and bring down day temperatures, but night temperatures remain steady.

They change the wind patterns in the northern parts of India. Without the presence of an active western disturbance cold winds from the Himalayas continue to blow in to the northern parts of India thereby allowing the prevailing cold conditions to continue and intensify.

Once the western disturbances pass, day temperatures increase but night temperatures dip significantly.   Parts of the plains of north-west, central and west India encounter cold wave, fog and ground frost conditions.

In January 2018, the cold wave claimed 100 lives in north India. Seven of the last 10 years have experienced cold waves. They have killed more than 2,000 people, mostly in the severe winter months of December and January.  Uttar Pradesh is the most affected state.

Cold wave conditions prevailed on most parts of Punjab and Haryana, recording temperature lower than Shimla

These cold wave conditions will continue until the end of December 2018.

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