COURTESY HT NOV 21

Winter arrives early in north as mercury dips
Met dept predicts that Delhi, Haryana and north Rajasthan could experience cold wave conditions for the next two days

Jayashree Nandi

letters@hindustantimes.com

New Delhi : Winter has arrived in many parts of northwest India, both in the hills and the northern plains, with the minimum temperature dipping below 5 degrees Celsius below normal in several cities, according to scientists.

On Friday, Gulmarg (Jammu and Kashmir) recorded a minimum temperature of -7° C, 5.5 degrees below normal. In Palampur (Himachal Pradesh), the minimum temperature was 3° C, 6.4 degrees below normal.

In the plains, town such as Hisar (Haryana), Churu (Rajasthan) and Adampur (Punjab), too, recorded minimum temperatures that were 4-5 degrees below normal. The Regional Meteorological Centre has warned that Delhi, Haryana and north Rajasthan could experience cold wave conditions for the next two days.

A cold wave is declared when minimum temperature is under 10°C and the departure from normal is 4.5° C for more than a day.

The onset of winter, which usually takes place around mid-December, seems to be happening earlier due to the influence of back-to-back western disturbances, according to scientists.They also said that La Nina, a global weather pattern which is prevailing this year, is also linked to substantially below normal temperatures in northwest India in winters. According to them, a colder than normal winter is expected this year.

“Winter months are January and February but normally cold is felt in December when both maximum and minimum temperatures are under 22° C and 10° C respectively,” said Kuldeep Shrivastava, head, regional weather forecasting centre.

Moderate La Nina conditions are prevailing over equatorial Pacific and sea surface temperatures are below normal over central and eastern equatorial Pacific Ocean, according to India Meteorological Department (IMD) Pune’s El Niño Southern Oscillation (ENSO) bulletin.

“After the western disturbance, which brought widespread snowfall to the entire western Himalayan region last Sunday, snowfall has continued in certain parts of the Himalayas. Again, a western disturbance will affect the region on November 22; it will bring widespread snowfall. So there is a substantial fall in temperature in the hills. In the plains, northwesterly cold winds are blowing and there are clear skies. So heat is radiating back at night, making mornings really cold. We are seeing minimum temperatures fall significantly quite early this year,” Shrivastava said.

He added that due to back-to-back western disturbances, the weather department expects snowfall in the hills to continue. This means that minimum temperatures will gradually fall further after the next western disturbance passes, he added.

According to IMD’s weekly weather report, northwest India recorded 220% excess rain in the week ending November 18 due to the influence of a western disturbance. For the next two weeks, the minimum temperature is likely to be 2°-5° C below normal. A cold wave is likely to prevail in isolated pockets of northwest India between November 20 and 26.

El Nino and ENSO are a periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific Ocean