The India Meteorological Department attributes the nearly dry January thus far to the absence of significant western disturbances this winter season, which resulted in an 80% precipitation deficit in the western Himalayan region in December.
The IMD said on Thursday that the reason for the thick layer of fog that has been covering the plains in the area since December 25 is also the lack of active western disturbances, which are weather systems that come from the Mediterranean region and bring unseasonal rainfall to northwest India.
According to a report authored by IMD scientists Krishna Mishra, Naresh Kumar, and RK Jenamani, this severe weather over north India is primarily due to the lack of active western disturbances over northwest India during December and January. Generally, 5-7 wester disturbances impact the region during these months. The region has not seen any strong western disturbance this winter so far, the scientists said.
This severe weather is mainly due to three reasons: lack of active western disturbances over northwest India, prevailing El-Nino conditions, and a strong jet stream, the scientists said.
Kumar said: “Fog formation requires three conditions: weak low-level winds, moisture, and overnight cooling. Strong western disturbances, characterized by strong winds and precipitation, disrupt these conditions.”
Strong jet streams, bands of strong wind that generally blow from west to east all across the globe and impact weather, have been prevailing over north India for the last five days. It is leading to subsidence of cold air and enhancing cold wave/cold day conditions over the region, Kumar said.
According to Sonam Lotus, the head of the meteorological center in Leh, Ladakh, the precipitation deficit is likely to have an effect on freshwater availability in the Himalayan region, which will further affect horticulture and agricultural production.
“January is peak winter but surprisingly, it is so warm in Ladakh and Kashmir that crops are blooming early, and this is very worrying,” he stated.
