The northern plains of the country come under tight grip of severe winters from December 15 till February 15. During this tenure, plains of the country come under frequent cold day/ cold wave conditions. The cold day conditions occur when any weather system is moving over the area which causes clouding thus leading to fall in temperatures.
After the passage of the system, winds are generally dry and cold and therefore result a dip in minimums. Whenever minimum temperatures are 4-5°C below their normal, it is then termed as a cold wave condition.
Cold wave conditions are invariably related with clear weather. On the other hand, cold day conditions are related with clouding. It is termed as a cold day when the day temperature falls, and night temperature rises. Whereas, during cold wave conditions, the minimums drop, and maximums rise. The minimums tend to drop when northerly winds blow.
Now, since past one week or so, no major weather activity has taken place. On the contrary, feeble systems are moving across Jammu and Kashmir. In wake of the winds, we can see the effect over the plains like Punjab, Haryana, North Rajasthan, Delhi and West Uttar Pradesh. The minimums over these areas is in single-digit only. Currently, the minimums are running 3-4°C below normal. As per weathermen, such weather conditions will continue to prevail for coming three to four days.
The temperatures can further go down by 4-5°C below normal. For the second successive day, the minimum temperature was around 5°C and will keep hovering around the same with a plus or minus. Thus, early morning, late evening and night will continue to have that peculiar chill in the air. Ground frost will be seen over large pockets. On the fog front, we are yet to see some dense fog, whereas visibility conditions will be okay. Fog is usually preceded by a wet spell and we are yet to see one.
For now, shallow fog with moderate in some pockets will prevail, simultaneously clearance will be fast too. Thus, dense fog is ruled out for some time. Today, at Palam airport the visibility was recorded at 700 metres which is very comfortable.
These days drop in temperature and humidity levels are on a higher end, but they tend to fade away once the sun sparkles and temperatures also shoot up. Thus, during early morning hours pollution level is in 'very poor' category. As per experts, PM10 will be on a very poorer side and PM2.5 will be on a poorer end. No major change in weather conditions is expected including temperature and wind profile. Hence, pollution levels too will behave will in a similar pattern.
Image Credit: Hindustan Times
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