The minimum temperature at Lucknow was 4 degrees below normal at 7.1 degrees on November 28 and it is coldest November day in the last 15 years. The state is shivering under cold conditions since October when the minimum temperatures throughout the month remained below normal by 1 to 4 degrees and hence the month became coldest in a decade or so.
A similar trend continues during November when minimum temperatures are below normal within the same range. Other places in the state also recorded below normal temperatures during the last 24 hours. The minimum temperature was 7.5 degrees Celsius at Kanpur, four degrees below normal, Allahabad recorded 10 degrees Celsius and Varanasi; 10.1 degrees Celsius.
Beside Najibabad, the coldest district in the state was Muzaffarnagar with minimum temperature 6.1 degrees Celsius followed by Rae Bareli with 6.8 degrees Celsius. Minimum temperature in Agra was 7.6 degrees Celsius and Fatehgarh 7.8 degrees Celsius.
The cold conditions are being attributed to the northerly dry and cool winds penetrating the plains. The minimum goes further down when these winds carry the chill from melting snows after the exit of Western Disturbance to push them in the region. The other reason of the cold weather is that the Western Disturbance does not affect the Indo-Gangetic plains as it does the northwest plains.
The Western Disturbance (moist and warm winds originating in the Mediterranean Sea and Atlantic Sea) usually remains in mid-tropospheric level while northerly blows under them in the lower levels. So, the Western Disturbance fails to restrict northerly winds from reaching these plains as it does in the northwest plain, which is at a much higher Sea level.
So, as the Western Disturbance would pass during the next 48 hours, the northerly winds could bring colder winds to keep the minimum temperatures below normal over Uttar Pradesh during the next week as well.