Two more western disturbances (WDs), the 16th and 17th such occurrences this season, will likely bring rainfall and chilly winds to the northern plains and snowfall in western Himalayas on March 6 and March 11, the India Meteorological Department said on Sunday, adding to the number and intensity of these weather phenomena that have surprised scientists.

The western disturbances are storms with cold air at their core that originate in the Mediterranean region and bring rain to north and northwestern India. At the most, five to six western disturbances usually affect northwestern India during the winter. “The intensity of WDs is unusual this year. Though we aren’t expecting heavy or widespread rainfall associated with the WD on March 6 because it appears to be a feeble one. Snowfall is likely in Jammu and Kashmir and Himachal Pradesh, while in the plains there will be cloudy skies and light rain. We are expecting a stronger WD on March 11 and 12, which is likely to bring widespread rain and snowfall but it is too early to give specific details,” said M Mohapatra, director general of meteorology, IMD.

On Sunday, several parts of Delhi reported rainfall and the day temperature in the national capital was 22.7 degrees Celsius, four degrees below normal, while the minimum was 11.5 degrees C, 2 degrees below normal. The IMD has predicted a generally cloudy sky and light rain for Monday.

Following the latest WDs, the temperatures may fall by 2 to 3 degrees temporarily, prolonging the winter feel, according to the weather department’s predictions. On March 3, following a western disturbance, the maximum temperature in Delhi was 19.3 degrees C, 8 degrees C below normal, while the minimum temperature was 11.5 degrees C, 2 degrees C below normal. The minimum temperature in Srinagar was 0.8 degree C, Lucknow 14 degrees C, Chandigarh 11.3 degrees C, Manali -1.4 degree C and Dehradun 10.6 degrees C.

Delhi experienced its second coldest March day in 27 years on Saturday, almost breaching yet another decades old record after Friday morning saw the coldest overall March temperature since 1979. Earlier in 2018, Delhi had witnessed the third coldest December in 50 years. IMD data showed that the average monthly minimum temperature in December 2018 was 6.7°C.

Mohapatra said the frequency of WDs this season was high because of the weakening of the polar vortex. The WD system develops due to a temperature difference between northern and southern latitudes. They are more intense this time because of the higher temperature gradient, which is a result of the weakening of the polar vortex, he said.

First Published: Mar 04, 2019 07:50 IST