Tuesday, 9 January 2018

Cold wave in North India

Cold wave continues to grip North India, temperature drops to season’s lowest in Jammu city

Weather monitoring agency Skymet Weather said that the intense cold will prevail over Delhi and adjoining areas the next few days as winds are blowing across the northwestern plains. The cold winds are because of the active Western Disturbance, a storm originating in the Mediterranean region that brings sudden winter rain to the northwestern parts of the subcontinent.



Cold wave grips most of north India, Lucknow at 0.1° Celsius

"A severe cold wave is likely at a few places in Punjab, Haryana, Chandigarh, Delhi, Uttar Pradesh and Rajasthan, and a cold wave at a few places in Bihar, Madhya Pradesh, Vidarbha and interior Odisha during the next 2-3 days," an IMD official said, adding that north India could experience normal rainfall during the next two weeks.

"The rains would drop the speed of west-northwesterly winds from J&K due to western disturbances. This could have a combined effect on Delhi's weather and help temperatures rise," a weather expert said. Winter in the valley has been extremely harsh this season with Leh town recording the coldest night of the season at minus 17.7° Celsius.


Siberian winds give India the shivers

PUNE: The biting cold in central and north India over the past few days is the fallout of a cold blast from the Arctic.

The entire north India, parts of central India, including Maharashtra, are feeling the chill in a supposedly warm winter because of a phenomenon that weather forecasters term 'negative Arctic oscillation', which brings a blast of cold Siberian winds to the Indian region.

Higher-level winds travel from Europe and Russia via Afghanistan and Pakistan to enter northern India. Weather forecasters claimed that occasional cold spells could be frequent now till the end of winter, especially in north India.

D Sivananda Pai, the head of the National Climate Centre, India Meteorological Department (IMD), told TOI that during the positive phase of the Arctic oscillation, bitterly cold weather remains confined to the Arctic region. "When this pattern becomes negative, which is the situation at present, a reversal of winds takes place and the cold travels southwards. These cold winds have now begun to enter the regions south of the Arctic, including India, resulting in a drop in temperature," said Pai.

The amplitude of the easterly wave activity, which had earlier warmed the peninsula, including central India, has now reduced because of the strong westerly winds.

"The negative Arctic oscillation began around a week back and may continue for some time now. This means, we could expect occasional cold spells from now on in various parts of the country, especially in the north India," said Pai.

B Mukhopadhyay, additional director-general of meteorology (research), IMD, said this winter had been unusual, marked by warmer temperatures with few cold spells. "In a usual winter, cold spells keep recurring after every 10-15 days, right from December. This time, cold spells began late due to predominance of easterly wave activity," said Mukhopadhyay.

The amplitude of the easterly wave activity usually increases in El Nino years. "The strong westerly winds have now overpowered the easterly wave effect, leading to a significant temperature drop in various parts of the country," he said.


Cold takes south India by surprise

Southern parts of the country have been hit by an unexpected and unprecedented drop in temperatures.
While the government has not confirmed this, media reports claim that several people have died of the cold in Andhra Pradesh. Hyderabad saw a decline of four degrees in its maximum temperature, while its minimum temperature dropped by 2°C.
On January 18, Bengaluru recorded a maximum temperature of 30°C, which was three degree below normal. The minimum temperature in the city was 13°C, a three degree dip. Similarly, Chennai registered a three-degree reduction in its minimum temperature–17.7°C–on January 17. India Meteorological Department (IMD) Chennai, however, says though they have not looked at past drops, this certainly is one of the lowest temperature recorded in several years. The cold is, however, within bearable limits, they add and no deaths have been reported. “There has been no significant change in maximum temperature in the city,” says S R Ramanan, director of IMD Chennai. He adds that parts of Tamil Nadu in the northern part had registered a drop of 5°C, but weather was quite predictable elsewhere in the state. At around 8°C, Mysore recorded its coldest day on January 19.

Nothing new about it
Ajit Tyagi, director general of IMD, maintains that there is nothing special about this phenomenon. “Usually, the warm oceanic waves from the Bay of Bengal keep the peninsular region warm. But their absence because of lack of cyclonic activity over the water body has caused cold winds from the northern part of the country to fill in the vacuum over peninsular India,” he adds.
M Rajeevan, senior scientist at the National Atmospheric Research Laboratory in Tirupati, concurs. He adds that the current atmospheric conditions in the peninsular region are conducive for this sort of weather variation. “The sky is clear and the air is dry. In these conditions, lower surface air can cool to a great extent,” he says. Rajeevan accepts that this sort of temperature dip is unusual for the peninsular region. “However, this is a natural variation, and doesn’t qualify as an extreme weather event.” Rajeevan adds that a weather circulation pattern called Arctic Oscillation, an atmospheric circulation pattern in which the atmospheric pressure over the Polar Regions varies in opposition with that over middle latitudes, has caused severe cold conditions throughout the world, and it is possible its impact is just spilling over to southern India too. Met officials are unsure how long the cold-wave like conditions will persist across the region.
Gopal Dabade, public health activist who runs a non-profit called Jagruti in Karnataka, says, “The cold has taken everyone by surprise. It is unlike anything seen in the recent years. People are unprepared for it. The homeless on the streets are most affected.” Unlike Delhi, there are also no provisions to distribute blankets to the homeless, he adds.

Will it affect health?
Anumita Roychowdhury, head of the air pollution and clean transportation programme at the Delhi based non-profit Centre for Science and Environment, says, “This climatic variation could impact the pollution problem in south India, where cities are becoming increasingly polluted. Normally during cold weather, calm wind prevails and air doesn’t disperse as rapidly. Air is stationery and dense. As a result pollutants build up close to the ground level.”
A K Sharma, professor of community medicine at University College of Medical Sciences, Delhi, says it’s unclear what specific health problems the weather change might create for people. “Generally, winter triggers two types of health problems in adults–respiratory and gastrointestinal. Chronic lung diseases may be exaggerated and asthma attacks may become more frequent. The weather could also trigger acute respiratory infection in children. If anything other than this is noticed, epidemiological studies should be conducted to analyse the effects.” He adds that people living in households where smoke is produced by burning of fuel are at risk of eye infections and allergic conjunctivitis in this season.
La Nina effect

Meanwhile, cold weather conditions continued to hit northern India with hilly states like Uttarakhand and Himachal Pradesh experiencing heavy snowfall. J R Kulkarni, senior scientist at the Indian Institute of Tropical Metereology at Pune, maintains this is usual for this time of the month. D S Pai, director of the long-range forecasting division, IMD Pune, says that people are feeling colder because of dip in maximum or day temperature. He adds that La Nina, a weather phenomenon generally associated with favourable monsoons and WHICH occurs when surface temperatures are cooler than normal in the western Pacific and warmer than normal in the eastern Pacific, might have been one of the factors behind this severe cold. “Weather is complicated, and La Nina is not the most important factor to influence temperature, but our analyses have shown that it can impact mean temperature.”


Cold wave kills nearly 100 in north India

Cold wave kills nearly 100 in north India
The Disaster Management Cell has predicted snowfall beginning 12 January for over four days.
While the Himalayan region witnessed early snowfall in October, there was a two-month dry spell which ended with another snowfall on New Year’s eve

The Kashmir valley is in the grip of an intense cold wave as it witnesses forty days of harsh winter, locally called ‘Chillai Kalaan’.


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