Day temperatures drop over North as cold winds blow in from across border

Vinson Kurian Thiruvananthapuram | Updated on December 17, 2019 Published on December 17, 2019

Kolkata woke up to a grey and wintry morning on Tuesday. Shallow to moderate fog is forecast for the next five days in parts of Bengal   -  Debasish Bhaduri

Cold-day conditions are expected to continue over most parts of Punjab, Haryana, Chandigarh, Delhi, Uttar Pradesh, Rajasthan and North Madhya Pradesh, an India Meteorological Department (IMD) update said.

This is due to the cold north-westerly winds blowing in from across the international border into a space left behind by an active western disturbance, its moisture carry, rising motion of air, and therefore warmth. The disturbance has since moved away and out of the country though associated moisture lingers in the air. The cold spell can be broken only when a follow-up western disturbance chugs in.

Cold-day conditions set in when maximum temperatures (day temperatures) are at or less than 16°C, a condition brought about by the lack of clouds. This allows the cold to seep into the ground.

The 24 hours ended Tuesday morning also saw dense to very dense fog in isolated pockets over Jammu & Kashmir, Punjab, Haryana, Chandigarh, Delhi, Chhattisgarh, West Rajasthan, hills of Bengal, Sikkim and West Madhya Pradesh. Moderate fog hung over Bihar, East Madhya Pradesh and Tripura.

The dense fog reduced visibility to 25 m at Amritsar and Phalodi; 50 m at Jammu, Bikaner, Bhopal, Raipur, Rajnandgaon and Cooch Behar; and 200 m at Ambala,Ganganagar, Rajgarh, Shajapur, Chhindwara, Malanjkhand, Guwahati, Silchar Purnea and Kailashahar. Dense fog may spread in the morning hours of tomorrow (Wednesday) over isolated pockets of Punjab, Rajasthan, Uttar Pradesh, Haryana, Chandigarh, Delhi, North Madhya Pradesh, North Chhattisgarh, Bihar, South Assam, Meghalaya and Manipur, Mizoram and Tripura. This is again a condition bequeathed by the western disturbance, with the lingering moisture it leaves behind getting cooled and condensed.

A fresh western disturbance is expected to affect the hills of North-West India from tomorrow (Wednesday) night, triggering isolated to scattered rain/snow in the same region. Poorly endowed (lacking depth and intensity), it may not cause any significant weather over the plains of the region. It was traced on Tuesday to somewhere over Iraq, and is expected to pass over Iran, Afghanistan and Pakistan before checking into North-West India.

Moderate fog

Meanwhile, the forecast for the next five days up to December 23 spoke about the possibility of shallow to moderate fog in isolated pockets over East India, including the plains of Bengal, Madhya Pradesh and parts of North-East India during the next next three days. A gradual fall in minimum temperatures by 2-4°C to is forecast over East India during this period. Forecast valid for the period December 22 to 24 said that isolated to scattered rain/snow is likely at some places in the hills of North-West India. Isolated rainfall is also likely over parts of Central India, South Peninsular India and the Islands.

In the South, light thunderstorms hit the southern parts of Coastal Tamil Nadu on Tuesday evening while it was heavy over the interior parts of Kollam and Thiruvananthapuram districts of adjoining South Kerala. Light to moderate rain is forecast for the southern parts of Tamil Nadu and Kerala over the next few days as well.

Published on December 17, 2019
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