During week 2, there would be slight rise in minimum temperatures as compared to week 1

According to the National Weather Forecasting Centreof the India Meteorological Department (IMD): 

Significant Features of past week (10 to 16 December, 2020):

• Two Western Disturbances and their induced cyclonic circulations in quick succession caused fairly widespread to widespread rainfall/snowfall/ thunderstorm activity over Western Himalayan Region and isolated to scattered rainfall/thunderstorm activity over adjoining plains of Northwest India during the 1st half of the week.
• An easterly waves caused scattered to fairly widespread rainfall/thunderstorm activity over Andaman & Nicobar Islands and isolated to scattered rainfall/thunderstorm activity over extreme south Peninsula and Lakshadweep islands during the week.
• Due to trough and wind confluence over central parts of the country, Central India received excess rainfall by 112% above Long Period Average (LPA) during past week.

Forecast for next two week Weather systems & associated Precipitation during Week 1 (17 to 23 December, 2020) and Week 2 (24 to 30 December, 2020) Rainfall for week 1: (17 to 23 December, 2020)  

• Under the influence of the easterly wave, scattered to fairly widespread rain/thundershowers very likely over Tamil Nadu, Puducherry &Karaikal, Kerala &Mahe and Lakshadweep area during next 3 days. Isolated heavy to very heavy rainfall very likely over Tamil Nadu, Puducherry &Karaikal on 17th December and isolated heavy falls on 18th & 19th December and over Kerala &Mahe on 18th  December and over Lakshadweep on 19th & 20th December, 2020.
• A fresh feeble Western Disturbance is very likely to cause light rain/snow over Western Himalayan region on 20th & 21st December, 2020.
• No significant rainfall likely over remaining parts of the country during the week (Annexure IV).
• Cumulatively, above normal rainfall likely over south peninsula and below normal rain/snow likely over Western Himalayan Region during week 1 (Annexure V).

Rainfall for week 2: (24 to 30 December, 2020)

• Due to the absence of any active Western Disturbance, near normal rain/snow also likely over Western Himalayan Region Under the influence of fresh easterly wave, normal to above normal rainfall activity likely over south peninsula (Annexure V).

Temperature/fog for week 1 & 2: (17 to 30 December, 2020)

• Minimum temperatures are between 2.0°C to 6.0°C over most parts of northwest India. These are markedly below normal (-5.0°C or less) at isolated places over Jammu & Kashmir, Ladakh, Gilgit-Baltistan & Muzaffarabad and Himachal Pradesh; appreciably below normal (-3.1°C to -5.0°C) at a few places over West Rajasthan and West Uttar Pradesh and at isolated places over East Rajasthan, East Uttar Pradesh, Saurashtra & Kutch and Haryana, Chandigarh & Delhi; below normal (-1.6°C to -3.0°C) at a few places over Punjab and Uttarakhand.

• No significant change in minimum and maximum temperatures would occur over Northwest India during next 2 days and rise by 2-3°C in minimum temperatures and 5-6°C in maximum temperatures during subsequent 3 days. Fall in minimum temperatures by 3-5°C would occur over East Madhya Pradesh, Vidharbha and Chhattisgarh and by 4-6°C over East India during first half of the 1st week. Fall in minimum temperatures by 2-3°C would occur over West India during next 2 days.

• Overall week as a whole, the minimum temperatures would be below normal by 2-6°C over most parts of northwest, central & east India and near normal or slightly above normal over remaining parts of the country during week 1.

• Cold Wave to Severe Cold Wave conditions would occur in some pockets over Punjab, Haryana & Chandigarh, West Uttar Pradesh and north Rajasthan during first half of the 1st week and decrease thereafter.

• Cold Day to Severe Cold Day conditions would occur in some to many pockets over Punjab, Haryana, Chandigarh & Delhi, north Rajasthan and northwest Uttar Pradesh during next 2 days and abate thereafter.

• During week 2, there would be slight rise in minimum temperatures as compare to week 1. However, the minimum temperatures would be below normal by 2-4°C over most parts of northwest, central & east India and near normal or slightly above normal over remaining parts of the country (Annexure VI).

Cyclogenesis:

• There is low probability of cyclogenesis over south Andaman Sea and adjoining southeast Bay of Bengal during first half of week 2.