The weak phase of northeast monsoon continued till November 10. It rectified since November 11 in association with an active easterly wave approached South India.
According to the National Weather Forecasting Centre of the India Meteorological Department, the easterly wave caused scattered to fairly widespread rainfall with isolated heavy falls over southeast Peninsular India towards the end of this week during which the week rainfall activity was below normal over all the homogeneous regions of the country.
Rainfall for week 1: (November 12-18, 2020)
- Under the influence of a trough in easterly at lower tropospheric levels extending from Sri Lanka coast to southwest Bay of Bengal off north Tamilnadu Coast and an embedded cyclonic circulation over Sri Lanka and another fresh easterly wave spell from November 14, 2020:
- Scattered to fairly widespread rainfall accompanied with thunderstorm & lightning very likely over Tamil Nadu, Puducherry &Karaikal, Coastal Andhra Pradesh, Kerala and Lakshadweep area during the week.
- Isolated heavy rain also very likely over Tamil Nadu, Puducherry &Karaikal and Coastal Andhra Pradesh during the week.
A fresh Western Disturbance very likely affects northwest India during November 13-16. Due to the active easterly wave & an anti-cyclonic circulation over northeast Madhya Pradesh, the easterly winds are likely to interact with the Western Disturbance over the plains of northwest India and adjoining central India. As a result of these systems:
- Scattered to fairly widespread precipitation very likely over Jammu & Kashmir, Ladakh, Gilgit-Baltistan & Muzaffarabad and Himachal Pradesh; Isolated rainfall over Uttarakhand on November 15-16, over plains of northwest India and adjoining central India on November 15, 2020.
- Isolated heavy falls also very likely over Jammu & Kashmir, Ladakh, Gilgit-Baltistan & Muzaffarabad on November 14-15, 2020.
- Light rainfall activity very likely over plains of northwest India and Madhya Pradesh on November 15-16, 2020.
Cumulatively, above-normal rainfall very likely over southeast Peninsular India and Western Himalayan Region; Below normal or no rainfall very likely over remaining parts of the country, the bulletin said.
Rainfall for week 2: (November 19-25, 2020)
- Rainfall activity likely to decrease over south Peninsular India and is likely to be below normal.
- Due to another Western Disturbance over the region, normal to above normal rainfall likely over Western Himalayan Region;
- Below normal or no rainfall very likely over remaining parts of the country.
Minimum Temperature for week 1 & 2: (November 12-25, 2020)
- The trend of decreasing minimum temperatures over the plains of northwest India continued till November 10 with below normal temperatures by about 3-4°C. It reversed with the prevailing increasing trend from November 11 in association with active easterlies in the country. The rising trend would continue over plains of northwest India & central India till November 15. Thereafter, minimum temperatures fall over the above region by 2-4°C due to passage of Western Disturbance and weakening of easterlies.
- Overall minimum temperatures are very likely to be below normal by 2-4°C over most parts of northwest India, above normal by 2° to 3°C over Uttar Pradesh & adjoining area of Madhya Pradesh and parts of south Peninsular India during week 1.
- It is very likely to decrease further during week 2 with below normal temperature over most parts of the country.
· No cyclogenesis (formation of Depression and above) likely over the north Indian Ocean during week 1.
· There exists a ‘low’ probability for cyclogenesis over the south Bay of Bengal and also over south Arabian Sea during the later part of week 2.