The Regional Meteorological Centre, Chennai, under the India Meteorological Department (IMD), expects parts of South Tamil Nadu to receive heavy rainfall on Thursday (day after tomorrow). The prevailing northerly to north-easterlies had sprung a surprise on Monday, with rains lashing down over parts of Tamil Nadu and Puducherry.
At 11 am yesterday (Monday), suburbs of Chennai were hit, as also Ramapuram, while Pulicat saw a heavier thunderstorm. Simultaneously, Srikalahasti, Sriharikota and Gudur in neighbouring South Coastal Andhra Pradesh also received light rain. Lighter thunderstorms began drifting West-South-West by 1 pm from Srikalahasti to Tiruttani, Tiruvallur and Sriperumbudur; by 3 pm to Arcot, Kanchipuram, Cheyyar, Vandavasi and Tindivanam; and by 6 pm to Arani, Sankarapuram and Kalrayan Hill Forests before opening a new front in the South across Mayiladuthurai, Velankanni, Vedaranyam and Thiruthuraipoondi, later into the night over Pattukottai and Manamelkudi and, early this (Tuesday) morning, over Chidambaram and Cuddalore.
The outlook for today (Tuesday) is partly cloudy for Chennai, with a temperature peak at around 28 degree Celsius, humidity lower at 68 per cent, winds north-easterly with only 10 per cent chance of rain. But it was already cloudy at the Chennai International Airport (MAA/VOMM) at 9.30 am, winds north-easterly and temperature at 29 degree Celsius. It will be mostly sunny over Puducherry and Coimbatore with a passing shower; partly cloudy over Salem, Tiruchirappalli and Thoothukudi; and partly to mostly cloudy over Madurai.
Cold day conditions
As for the weather elsewhere in the country, the IMD said cold day conditions continue to prevail in isolated pockets over Punjab, Haryana, Chandigarh, Delhi and Rajasthan for today (Tuesday) and may abate from tomorrow (Wednesday) as a feeble western disturbance with warmth (from moisture carry) upfront envelopes the hills of North-West India. It may likely cause isolated to scattered rain/snow over the same region.
This western disturbance is not likely to cause any significant weather change over the plains of North-West India where the skies are now clear, allowing the winter cold to sink to the ground level. Cold day conditions are declared when the maximum (day) temperature is less than or equal to 16 degree Celsius in the plains of North-West India. Foggy conditions prevail here during winter for several days or weeks. The minimum (night) temperature on these days remains above normal, while the maximum (day) temperature remains well below normal.
The IMD said on Tuesday that dense fog in isolated pockets is likely over Punjab, Bihar, South Assam, Meghalaya, Manipur, Mizoram and Tripura in the morning hours until tomorrow (Wednesday).
Deficit week
Meanwhile, in a review of the national weather, Jatin Singh, Managing Director of private forecaster Skymet Weather, said that the latter half of the past week witnessed heavy snowfall in the hills of North-West India and widespread rains in the plains before they migrated to Uttar Pradesh, Jharkhand and Bihar. The rainfall was accompanied by hailstorm at certain places and resulted in cold day conditions in certain pockets of the plains. In the South, the North-East monsoon was subdued, which led to a deficit week in all five meteorological subdivisions. Unseasonal rains broke out over parts of Madhya Pradesh and Maharashtra.
In the wake of the active western disturbance, the mornings will be cold and foggy in the plains of North-West India and the minimum temperature is likely to remain in single digits. Cold wave conditions are expected to prevail over the hills as well. A fresh western disturbance is likely to result in moderate snowfall and rains in the hills. Parts of Punjab, Haryana and Rajasthan along the foothills will also be affected. In continuation of the last few days of the previous week, unseasonal rains could materialise over parts of Maharashtra, Madhya Pradesh, and Chhattisgarh in the first two days of the week. Hailstorm is likely at a few places. Fine weather with a slight dip in the temperature will be experienced during the rest of the week at these places.
Cold and misty mornings with a drop in minimum temperature will be the outcome for Bihar, Jharkhand, and Bengal. Light rainfall accompanied by thunder is likely to remain confined to Arunachal Pradesh and upper Assam. The rest of East and North-East India will be free of any weather activity.
Towards the South, the North-East monsoon will continue to remain subdued this week. This is likely to be the second deficit week in succession. Light rainfall activity will be confined to the extreme southern parts of Coastal Tamil Nadu. The North-East monsoon deficit which reads about 17 per cent now in Chennai will possibly increase and go beyond the 20 per cent mark, Jatin Singh said in his observations.
Pollution down
Active rainfall conditions over parts of Punjab, Haryana, Rajasthan, Uttar Pradesh and Delhi have brought the pollution down from the very poor to severe category. The rain caused the pollutants to wash away; the air quality over Delhi has improved significantly to remain in the moderate category at most places. This is expected to stay as such at least during the first half of the week. Thereafter, the formation of shallow fog and mist will result in a slight deterioration of air quality. However, pollution levels are not expected to fall into the very poor to severe category this week. Most places will experience moderate air quality, and only at a few places will it slip back to the poor category.
(The National Weather column will resume on January 5, 2020)
Chennai bloggers and their followers continue to track the hit-and-miss thunderstorms over parts of Tamil Nadu and Puducherry as the 2019 North-East monsoon finds itself in the midst of an elaborate process of signing off.
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