National Weather Forecast: Sunday, January 19

A brief interlude between two western disturbances will bring cold day conditions (when the day maximum temperature is around 16 degree Celsius or lower) over parts of North and East India for the next two or  three days.

Cold day conditions are therefore forecast over West Uttar Pradesh, West Madhya Pradesh and Haryana today (Sunday) and may improve with the arrival of a fresh western disturbance, its warmth and associated clouding. 

Cold day conditions in North-West

Being waves with lower pressure, western disturbances feature an ascending motion of air and moisture-carry, though their rear is marked by descending air that brings the upper level cold to sit over the ground. The clouds help trap the solar radiation from the ground and prevent it from escaping into the higher levels of the atmosphere. According to the India Meteorological Department (IMD), cold wave conditions may hit isolated parts of Saurashtra, Kutch and Rajasthan tomorrow (Monday). The cold conditions will also throw down a layer of fog over North-West India as they freeze the lingering moisture left behind in the atmosphere by the preceding western disturbance.

Dense to very dense fog forecast

The IMD has also forecast dense to very dense fog over parts of  Punjab, Haryana Chandigarh, Delhi, Uttar Pradesh and Bihar,   while it will    be dense over parts of  Uttarakhand, North Rajasthan and North Madhya Pradesh during next two or  three days, and over the hills of Bengal and Odisha from today (Sunday).

Yesterday (Saturday), Alappuzha (Kerala) recorded the highest maximum (day) temperature of 35.3 degree Celsius while Amritsar (Punjab) recorded the lowest (night) minimum temperature of 3.6 degree Celsius. On Sunday morning, among the metros, Chennai was the hottest, at 27.8 degree Celsius, and Delhi was the coolest, at 7.8 degree Celsius. Tonight (Sunday), Srinagar might record the lowest temperature at -3.0 degree Celsius while Madurai and Kochi are expected to be the warmest at 24 degree Celsius. 

It is the presence of the Himalayas that prevents cold, dry Arctic northerly winds from blowing into the subcontinent, keeping South Asia and India much warmer than corresponding temperature regions in the other continents. On an average, six or seven disturbances per month (including the induced/offspring cyclonic circulations) move across India during   winter. Intervals between two such disturbances bring in the colder Arctic air, though the mercury does not fall to the level of the freezing and stormy levels currently being witnessed at much higher latitudes. (For instance, a winter/snow storm, referred to as the bomb cyclone,  has just hit Newfoundland in Canada). 

Visibility brought down 

Sunrise at Goregaon, a suburb in western Mumbai (file photo)

Western disturbances originate in comparably warmer southern latitudes such as the Mediterranean and  the Caspian Sea and move east across West and South-West Asia, the Middle-East,  Iraq, Iran, Afghanistan and Pakistan before entering North-West India and further into East India. Depending on their strength, depth or intensity, they affect other parts of the country, even down to the South, modulating weather   locally from cooler climes to showery spells when associated westerly   winds interact with the easterly wind regime. 

Early this (Sunday) morning, dense to very dense fog blanketed parts of  Punjab, West Uttar Pradesh, West and East Rajasthan; it was dense over Haryana, Chandigarh, Delhi and East Uttar Pradesh, and moderate over the hills of Bengal, Sikkim, Odisha and East Uttar Pradesh. Visibility was     below 25 metres in  Agra,  Amritsar, Chandigarh, Ganganagar, Churu and Kota; below 50 m in Patiala, Hissar, Palam (Delhi), Bahraich and Bhopal; and below 200 m in   Malda and Chandbali. Per an IMD outlook, these conditions may variously persist over these regions, as mentioned already. 

Showery in parts of South

In the South, the North-East monsoon may have made a delayed exit on January 9, but isolated showers from easterly winds persist over parts of Tamil Nadu and Kerala. An IMD outlook for today (Sunday) has said that the spotty showers witnessed over the past couple of days over parts of Tamil Nadu may continue, with almost all the major cities in the State, including Chennai, forecast to witness brief wet spells.

In fact, satellite maps indicated a helpful area of relatively lower pressure along the coast of Andhra Pradesh and Tamil Nadu and its adjoining interior - Nellore, Chennai, Puducherry, Salem, Tiruchirappalli, Nagapattinam, Madurai and Tirunelveli - as well as along the West coast - Kerala, Karnataka,  Mumbai and the rest of Maharashtra. International models indicated plenty of sunshine under a clear sky for Mumbai; a foggy morning becoming sunny and clear for Kolkata; partly cloudy skies turning generally sunny for Chennai; foggy becoming sunny for Puducherry; mix of sun and clouds for Salem; cloudy to partly cloudy for  Coimbatore; foggy morning turning partly cloudy for  Tiruchirappalli; partly to mostly cloudy for  Madurai; foggy morning turning partly cloudy for Hyderabad; and a mix of sun and clouds for Bengaluru. 

Tweets from the famed bloggers of Chennai helped bring a better perspective to the weather trends in the South.

Temperature and general weather outlook,  January 19, Sunday 

(Source: India Meteorological Department)  

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