Delhiites to brace for cold wave, dense fog & more disruptions for next 2 days
The IMD has issued an ‘orange’ alert for Delhi for Tuesday and Wednesday, with officials saying it was on account of the combined effect of low temperatures and dense fog, with the possibility of air and rail transport disruptions.
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On Monday, the national capital recorded the lowest minimum temperature for the winter so far — 3.3 degrees Celsius – which is four degrees below normal for the Safdarjung weather station, the city’s base observatory. (Express photo by Praveen Khanna)While cold wave conditions are set to persist in Delhi for the next two days, dense fog is likely till January 19, going by the India Meteorological Department (IMD) forecast.
The IMD has issued an ‘orange’ alert for Delhi for Tuesday and Wednesday, with officials saying it was on account of the combined effect of low temperatures and dense fog, with the possibility of air and rail transport disruptions.
On Monday, the national capital recorded the lowest minimum temperature for the winter so far — 3.3 degrees Celsius – which is four degrees below normal for the Safdarjung weather station, the city’s base observatory. This was the fourth consecutive day that the minimum temperature has remained below 4 degrees Celsius in Delhi.
Cold wave conditions are expected in parts of the city on Tuesday and Wednesday — the IMD marks a ‘cold wave’ in the plains when the minimum temperature is 4 degrees or lower. Dense to very dense fog (visibility of less then 200 m) is also on the forecast for the two days.
Clear skies and the availability of a significant amount of moisture have been contributing to the cold and foggy conditions, according to IMD scientists.
“Conditions are favourable for these low minimum temperatures — the skies are clear across northwest India. This means that in the day time, temperature rises, and at night, since there are no clouds, the energy gained by the earth during the day time goes back to the atmosphere rapidly in the early hours. That brings with it a rapid fall in temperatures, when the minimum temperature falls below 4 degrees. Along with this, moisture is available since humidity in January usually stands at around 80% to 90% and wind speed is low, so fog forms in the early hours.
This fog layer has been dissipating during the day,” said Kuldeep Srivastava, scientist, IMD.
Only a western disturbance is likely to break this spell of low temperatures; this is unlikely to affect the plains, at least for the next five to six days, Srivastava added. Western disturbances can bring cloud cover.
“Western disturbances are the only systems that regulate weather over northwest India. With cloudiness, the minimum temperature might increase, but a feeble western disturbance that is likely to affect the western Himalayan region this week will not have any impact on the plains,” he added.
Srivastava pointed out that January is the coldest month of the year for Delhi. The mean daily minimum temperature in January is 7.5 degrees, the lowest for any month of the year, followed by 8.4 degrees in December, going by data from 1991 to 2020. January is also the month with the highest average number of days with fog — 21.6 days — followed by December with 19.2 such days.
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