The upper air cyclonic circulation moved over Sikkim & neighbouring areas on 25th, as a north-south trough over Sub-Himalayan West Bengal & Sikkim on 26th & 27th, as a cyclonic circulation over Meghalaya & neighbouring areas on 28th and caused scattered rainfall over Arunachal Pradesh on most of the days of the week and at isolated places over Assam & Meghalaya and Sub-Himalayan West Bengal & Sikkim on many days of the week. The upper air cyclonic circulation at 1.5 km above mean sea level over southeast Arabian Sea off Kerala Coast on 25th & 26th caused scattered rainfall over Lakshadweep and isolated rainfall over Kerala on a few days of the week. Last week’s trough of low at mean sea level over southeast Bay of Bengal & neighbouring areas moved west-southwestwards towards Equatorial Indian Ocean and adjoining southwest Bay of Bengal off the southern Sri Lankan coast caused scattered rainfall activity over Andaman & Nicobar Islands on many days of the week. The Western Disturbance as an upper air cyclonic circulation over Iraq & neighbouring areas on 27th, moved eastwards through northern parts of Western Himalayan Region and caused scattered rain and snow over Jammu & Kashmir between 0830 hours IST of 30th and 0830 hours IST of 31st January 2018 FOG & COLD WAVE Dense to very Dense fog was observed at a few places over Eastern Uttar Pradesh on most of the days of the week and over Bihar on many days of the week; at one/two places over Western Uttar Pradesh, Haryana, Chandigarh & Delhi, Punjab on many days of the week and over Assam & Meghalaya, Nagaland, Manipur, Mizoram & Tripura, northern parts of Rajasthan, Uttarakhand, Sub-Himalayan West Bengal & Sikkim, Odisha, Himachal Pradesh on one/two days of the week Cold wave/severe cold wave conditions prevailed at isolated places over Telangana, Vidarbha, north Madhya Pradesh, on many days of the week and on a few days of the week over Rajasthan, Odisha, Himachal Pradesh, Punjab and Marathawada. Ground Frost: Ground Frost observed at isolated places in Haryana & Punjab on one/two days of the week. During the week lowest minimum temperature of 2.0°C was recorded on 25th January 2018 at Bhilwara (Eastern Rajasthan) in the plains of the country. Cold day/ severe cold day conditions prevailed at isolated places on a few days of the week over Uttar Pradesh, Haryana, Punjab, Bihar, Sub-Himalayan West Bengal and on one/two days of the week over Uttarakhand and Rajasthan. During the week the lowest maximum temperature of 11.4°C was recorded on 26th January 2018 at Nazibabad (West Uttar Pradesh) in the plains of the country. Cold wave/Severe Cold Wave
The cumulative rainfall Sub-Division wise for the week (25-31 January 2018) predicted by the IMD GFS model shows that Andaman & Nicobar Islands would receive excess rainfall, and Gujarat Region and Konkan & Goa would receive normal rainfall. whereas no Sub-Divisions have received excess rainfall and two sub-divisions viz. Arunachal Pradesh and Assam & Meghalaya received normal rainfall. With excess rainfall predicted for Andaman & Nicobar Islands, they received deficient rainfall and the normal rainfall was predicted for certain sub-divisions, but they have not received any rainfall. The other sub-divisions for which largely deficient rainfall was predicted have not received any rainfall. They are Himachal Pradesh, Eastern Uttar Pradesh and Bihar. Overall Model has predicted well for 26 out of 36 Sub-Divisions of the country.
During the week, rainfall over the country as a whole was 89 per cent below the long period average (LPA). Only Arunachal Pradesh and Assam & Meghalaya received normal rainfall and Andaman & Nicobar Islands received deficient rainfall. All the other Sub-divisions either received largely deficient/no rainfall. Details of the rainfall distribution over the four broad homogeneous regions of India are given below:
For the country as a whole, cumulative rainfall was (-85 per cent) of LPA as on 31st January 2018. Cumulative rainfall was deficient over the Southern Peninsula. Rainfall was excess over Andaman & Nicobar Islands; deficient over Arunachal Pradesh, Nagaland, Manipur, Mizoram & Tripura and Lakshadweep. The other Sub-divisions received largely deficient/no rainfall over the rest of the Sub-divisions of the country. Details of the rainfall distribution over the four broad homogeneous regions of India are given below:
Rainfall activity will be near normal over Nicobar Islands and below normal rainfall activity over Western Himalayan Region.
Rainfall activity will be above normal over Western Himalayan Region, Nicobar Islands and some Sub-Divisions of East & Northeast India and normal over plains of Northwest India. Heavy rain/snow will occur at isolated places over Western Himalayan Region.