Weather report: Despite below-normal minimum temperatures in north India, why doesn't it feel so cold?

The nights are getting chiller everywhere in India with every passing day of December. Delhi’s base observatory, Safdarjung, recorded the season’s lowest minimum temperature so far by registering 4.9°C on December 15; it was 4°C below normal, technically registering the first coldwave of the season. Minimum temperature reported in various other stations of plains of north India on Friday: Ropar: 4.2°C Adampur: 4.4°C Amritsar: 4.8°C Bareilly: 4.9°C Moga: 5.2°C Yamunanagar: 5.5°C Hisar: 5.6°C Pathankot IAF: 5.6°C Gurdaspur: 5.8°C Karnal: 6.0°C Sikar: 6.2°C Icy cold nights continue to prevail in the western Himalayas, interestingly on Friday Srinagar reported colder night compared Gulmarg the reason for the same is attributed to a weak western disturbance lead cloud cover which was present over Gulmarg but not over Srinagar, clear skies in night leads to higher drop in temperature. Minimum temperatures on December 15 in Jammu and Kashmir: Shopian: -6.0°C Pahalgam: -5.8°C Srinagar: -5.4°C Pulwama: -5.3°C Gulmarg: -5.0°C Anantnag: -5.0°C Bandipora: -4.9°C Kupwara: -4.2°C Qazi Gund: -3.8°C Banihal: -0.5°C Bhaderwah: -0.2°C Batote: 2.1°C Samba: 4.6°C Reasi: 5.5°C Katra: 6.6°C Jammu: 6.7°C Under the influence of northerly winds cold conditions intensified in parts of Uttarakhand as Pantnagar in foothills recorded 3.2°C minimum temperature. Other stations in the state: Harshil: -3.4°C Matela: -1.9°C Jakholi: 0.0°C Garud: 0.6°C Mori: 0.7°C Mukteshwar: 1.6°C Thailisain: 2.2°C Shama: 2.7°C Bageshwar: 3.0°C Joshimath: 3.3°C Champawat: 4.4°C Dehradun: 6.0°C Despite below-normal minimum temperatures, why doesn’t it feel so cold? Under clear skies temperatures tend to fall during night. This has been the pattern across winter this year so far, conditions for temperature inversion are exactly opposite during the daytime if it is clear sky and the winds are blowing — temperature is going to rise when Sunny conditions are prevailing. Another key point which is yet to emerge this year is fog, it is a very crucial phenomenon that occurs every year in north India but this year so far in the first 15 days of December there have been no major trace of dense fog, except a few cases of moderate fog reported from certain parts of Punjab and Haryana. Fog in the daytime helps restrict temperature to increase which has been missing so far hence there is a very clear pattern of above normal day time temperatures in north India, typical cold and foggy winters are yet to set in. [caption id=“attachment_13516032” align=“alignnone” width=“923”] Minimum temperature anomaly has started to become below normal in parts of north and east India as we enter second half of December[/caption] Weather conditions across the country remained dry in the past week, even in parts of Tamil Nadu where it usually rains a lot during the last leg of the north east monsoon; mostly dry weather conditions and limited rainfall this week. It’s on Sunday when the southern tip of the country experienced extremely heavy rains as a cyclonic circulation has induced near Sri lanka and south Tamil Nadu. Palayamkottai, a town in Tamil Nadu saw 300 mm till 8.30 pm on Sunday night, It is now the wettest day ever for Palayamkottai in 150 years since 1871, It broke the all time record of 292.8 mm from January 9, 1963. Some previous dated highest rainfall from the town; 31-10-2002: 240 mm 10-11-1933: 202.7 mm 10-12-1931: 200.7 mm The pan India actual rainfall so far in the period of 1st October till 17th December stands at 107.9 mm against the normal of 114.5 mm, the departure from normal currently stands at -6 percent the rainfall deficiency has increased by 3 percent week over week as subdued rains have. occurred across south India. Subdivision wise seasonal rains till December 17, 2023: • Southern Peninsula: Actual 224.5 mm against the average of 265.3 mm, -15 percent departure from normal. • East and northeast India: Actual 175.0 mm against the average of 152.7 mm, +15 percent departure from normal. • Northwest India: Actual 51.9 mm against the average of 42.3 mm, +23 percent departure from normal. • Central India: Actual 59.3 mm against the average of 74.3 mm, -20 percent departure from normal. [caption id=“attachment_13516052” align=“alignnone” width=“699”] Subdivision-wise season rainfall in India during the period of October 1 till December 17 so far[/caption] Current synoptic weather features influencing weather in India as on 18th December, 2023: • The cyclonic circulation over the Comorin area and neighborhood extending up to 5.8 km above mean sea level persists. • The western disturbance, as a cyclonic circulation over Jammu and neighbourhood, at 3.1 km above mean sea level with a trough aloft in mid-tropospheric levels and its axis at 5.8 km above mean sea level roughly along Long. 74°E to the north of Lat. 32°N persists. • A fresh western disturbance is likely to affect western Himalayan region from December 22, 2023. • The induced cyclonic circulation over north Haryana and neighbourhoods at 0.9 km above mean sea level has become less marked. All India weather forecast till December 24, 2023: Post the landfall of Cyclone Michaung the northeast monsoon never recovered in southern states, it is the last leg of the season and rainfall has significantly reduced, again this week there won’t be any major rain in the states. Parts of south Tamil Nadu and south Kerala will experience light to moderate rains from December 18 to 20; the rest of north Tamil Nadu, Kerala, Karnataka, Goa, Andhra Pradesh, and Telangana will experience bone-dry weather conditions for the entire season until December 24. No change in weather conditions is forecasted in central, east and northeast India, the flow of northwest winds will maintain until December 21 and nights will continue to stay cold in the region with sub 10°C temperature range, under clear skies days will be slightly warm in Maharashtra, Gujarat, Chhattisgarh, Madhya Pradesh, Odisha, West Bengal, Jharkhand, Bihar, Sikkim, Arunachal Pradesh, Assam, Meghalaya, Mizoram, Manipur, Nagaland, Tripura. Rains are not projected to occur in any of these states till December 24, dry weather conditions will continue to thrive. Colder night, foggy mornings in north India Recently, a weak western disturbance affected the western Himalayas with light snowfall. This week, northwest winds will resume from the hills to the plains of north India. It is anticipated that temperatures will fall further by 1 to 2°C from current levels. As a result, a coldwave will impact some parts of Punjab, Haryana, Delhi NCR, and north Rajasthan from December 19 to 21, as the minimum temperature to be recorded in the range of 3 to 7°C should be 4°C below normal in some cities. Bone chilling nights will also get a cover of fog in the early morning hours as moderate to dense fog is predicted in Punjab, Haryana, Delhi NCR, Rajasthan, and the foothills of Uttar Pradesh in the early hours of the day, mainly between 4 and 9 am. Days will be clear and sunny, and they will also be comfortable as the temperature will hover in the range of 19 to 25°C at most parts. Later this week, a slightly moderate western disturbance is expected to approach north India. As a result, the western Himalayas and plains will experience cloud cover during December 22–23. The wind pattern will change from north west to south east, and along with an increase in moisture in the atmosphere, chances of light rains will emerge in Punjab, Haryana, Delhi NCR, and Rajasthan, though they are likely to be localised in nature. Light to moderate snowfall will occur at most peaks in Ladakh, Kashmir, Himachal Pradesh, and Uttarakhand, and many hill stations will record at least light snowfall in this spell. Despite being moderate in nature, the upcoming western disturbance might turn tables, and a proper chilly winter might arrive in India. Christmas onwards, nevertheless, is the time of year when peak winter kicks in. The writer, better known as the Rohtak Weatherman, interprets and explains complex weather patterns. His impact-based forecasts @navdeepdahiya55 are very popular in north India. Views expressed in the above piece are personal and solely those of the author. 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