As we entered into thick of winter season, a thick layer of fog has engulfed entire Indo-Gangetic plains and extending up to northeastern parts of the country. Starting from Punjab in west to Tripura in Northeast India, all are presently reeling under the grip of varying intensity.
In fact, this fog has led to intensification of winter chill across these areas, leading to cold wave conditions. According to Skymet Weather, in the absence of any active Western Disturbance, chilly winds are blowing uninterruptedly across Punjab, Haryana, Delhi, Uttar Pradesh and Bihar. This has dropped the mercury over these areas. Moreover, winds are very light in the nature.
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For the formation of fog, we require three factors that include light winds, low minimum temperatures and high humidity. And, for the past 2-3 days, all these factors are prevailing over these regions. Have a look at the following image that would make you understand better about the fog status in the country.
Image credit: IMD
Further for next one week, country is likely to see some relief from foggy conditions. This would be by the virtue of winds picking up pace. Thereafter also, moderate to shallow fog with dense fog in isolated fog cannot be ruled out.
Ongoing period is the most conducive phase for the formation of fog. However, it is very rare that you get to see dense fog along the northwestern and Indo-Gangetic plains at the same time. As per weathermen, fog is a winter driven phenomenon and that there is no such system that could affect the weather over such huge land mass at once, be it an induced low, a cyclonic circulation or a trough.
Passage of any weather system usually takes at least 2-3 days to travel across the region. But there are few areas that are exception and see fog even in the absence of any significant weather system. Factors such as terrain, water bodies and remnant of the weather systems also lead to formation of fog. For instance, fog in Northeast India is purely due to localized factors.
East Uttar Pradesh and Bihar are most fog prone areas during December and January. Places such as Gorakhpur, Varanasi, Gaya, Patna, Allahabad and Lucknow are the worst affected pockets and battle poor to very poor visibility due to fog.
Meanwhile in north, Jalandhar, Ludhiana, Amritsar, Saharanpur and Ambala are the most affected areas.
Image Credit: India TV
Any information taken from here should be credited to skymetweather.com
