According to Skymet Weather, the sudden drop in the night temperatures during the last 24 hours can be attributed to the clearance of dense layer of smog, which was acting as greenhouse.
Whenever sky is obscured, it restricts the outgoing longwave radiation from the earth surface. These radiations get trapped between earth surface and the layer of smog, leading to rise in minimums over Delhi-NCR.
Further, a fresh Western Disturbance is expected to affect the Western Himalayas by night of November 11. It may give some rain or snow over the hilly states but will not affect the northern plains in terms of any weather activity.
However, the passage of the disturbance will change the wind pattern to southwesterly or southeasterly over Punjab, Haryana, Delhi and even North Rajasthan. With this, we can expect marginal rise in minimum temperatures by 1 or 2 degrees during the next 48 hours.
As soon as, the Western Disturbance will move away, temperatures will once again start falling November 13 onwards. Meanwhile this time, drop will be much steeper as the northerly winds will start travelling from Himalayas which would receive fresh snowfall.
This will mark the commencement of Delhi’s notorious winter but with poor air quality.
Image credit: Rediff.com
Any information taken from here should be attributed to skymetweather.com