Weather of Northern Plains remained dry since October 25th. Winter rains usually occurs due to the approach of western disturbances over Western Himalayas as well as over northern plains. On an average three to four Western disturbances approach Western Himalayas in the month of November.
Until now weather of north India remained dry due to absence of western disturbance which is unusual. We do not expect any significant Western disturbance or weather system approaching Western Himalayas for another week or so.
Whenever there is a significant gap between two Western disturbances, winds continue from northwest direction which is usual pattern during winters. Continuous flow of dry and cold winds from northwest lead to drop in temperatures.
Now we expect temperatures of Northern Plains a will continue to see gradual fall until next week. Some districts of Punjab, Haryana, North Rajasthan and isolated pockets of Delhi and NCR may witness single-digit minimums by next week.
Minimum of Delhi and NCR would have been dropped further leading to winter chill. But severe air pollution is acting as greenhouse effect and not allowing minimums to fall significantly.