{"id":54252,"date":"2019-12-28T15:52:00","date_gmt":"2019-12-28T10:22:00","guid":{"rendered":"https:\/\/blogadmin.forumias.com\/?p=54252"},"modified":"2020-02-26T15:53:43","modified_gmt":"2020-02-26T10:23:43","slug":"7-pm-why-this-winter-is-extra-cold-28th-december-2019","status":"publish","type":"post","link":"https:\/\/forumias.com\/blog\/7-pm-why-this-winter-is-extra-cold-28th-december-2019\/","title":{"rendered":"7 PM | Why this winter is extra cold| 28th December 2019"},"content":{"rendered":"\n<p><strong>Context:&nbsp;<\/strong>Cold wave in Northern India.<\/p>\n\n\n\n<p><strong>More in news:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>India\nMeteorological Department (IMD) issued warning of cold day to severe cold day\nconditions in many pockets are very likely over Punjab, Haryana, Chandigarh,\nDelhi and Uttar Pradesh.<\/li><li>Dense\nfog is very likely to engulf Uttar Pradesh, some pockets over Punjab and\nHaryana, Chandigarh, Delhi and also a few parts of north Rajasthan.<\/li><\/ul>\n\n\n\n<p><strong>Definitions:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Cold\nDay:&nbsp;<\/strong>A cold-day condition is said to\nprevail when the maximum temperature during the day is at least 4.5\u00b0C below\nnormal.<\/li><li><strong>Severe\nCold Day:&nbsp;<\/strong>If the maximum\ntemperature is at least 6.5\u00b0C below normal, it is classified as a severe cold\nday.<\/li><li><strong>Cold\nwave:<\/strong>&nbsp;Cold wave is characterized by a\nrapid and marked fall of temperature. The term \u2018cold\u2019 describes an unusual fall\nin temperature that is triggered by the transport of cold air masses into a\nspecific area.&nbsp; The \u201cwave\u201d in cold wave is apparent in the upper-air flow\n(the jetstream), which is usually amplified into a strong ridge-trough pattern\nduring a major cold outbreak. Cold waves affect much larger areas than\nblizzards, ice storms, and other winter hazards.&nbsp;<\/li><\/ul>\n\n\n\n<p><strong>Formation of Cold Waves:&nbsp;<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>The\ncore requirement of a cold wave at the surface is a strong high pressure center\nthat forms during winter in high latitudes.<\/li><li>Cold\npolar or Arctic air masses are relatively shallow, extending one to several\nkilometre above the surface.<\/li><\/ul>\n\n\n\n<p><strong>The Fact-Sheet of normal winters:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>In\nDecember, the maximum daily temperature does not rise beyond 16-18\u00b0C in most of\nPunjab, Haryana, Himachal Pradesh and western Uttar Pradesh.<\/li><li>In\nDelhi and northern Rajasthan, daily maximum temperatures are usually not over\n20-22\u00b0C for most of December.<\/li><\/ul>\n\n\n\n<p><strong>The \u2018Unusual Winters\u2019:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>The\nnorthern region is expected to record its second-coldest December since 1901.<\/li><li>As\nper IMD, the mean maximum temperature for December was less than 20 degrees\nCelsius only in 1919, 1929, 1961 and 1997.<\/li><li>The\nmost intense cold day when maximum temperatures fell 7\u00b0to over 12\u00b0C below\nnormal was on December 25 over Punjab, Haryana,&nbsp;Chandigarh, Delhi, Uttar\nPradesh, north Rajasthan and some isolated areas in Bihar and Madhya Pradesh.<\/li><\/ul>\n\n\n\n<p><strong>India Meteorological Department\n(IMD):<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>The\nIMD is the national meteorological service of the country and it is the chief\ngovernment agency dealing in everything related to meteorology, seismology and\nassociated subjects.<\/li><li>It\nwas formed in 1875.<\/li><li>The\nIMD is under the Ministry of Earth Sciences, Government of India.&nbsp;<\/li><li>IMD\nmandate:<ul><li>To\ntake meteorological observations and provide current information and\nforecasting information for the most favorable operation of weather-dependent\nactivities such as irrigation, agriculture, aviation, shipping, offshore oil\nexploration and so on.<\/li><\/ul><ul><li>To\nwarn against severe weather phenomenon such as tropical cyclones, dust storms,\nnorwesters, heat waves, cold waves, heavy rains, heavy snow, etc.<\/li><\/ul><ul><li>To\nprovide meteorological related statistics needed for agriculture, industries,\nwater resources management, oil exploration, and any other strategically\nimportant activities for the country.<\/li><\/ul><ul><li>To\nengage in research in meteorology and allied subjects.<\/li><\/ul><ul><li>To\ndetect and locate earthquakes and evaluate seismicity in various parts of the\ncountry for developmental projects.<\/li><\/ul><\/li><\/ul>\n\n\n\n<p><strong>Probable causes of such extreme\nweather:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Climate\nChange:&nbsp;<\/strong>The unusually cold\nDecember this year could just be another instance of extreme climates becoming\nmore and more frequent, a result of climate change.&nbsp;<ul><li>Across\nthe world, the frequency and intensity of both heatwaves and cold waves have\nincreased in the last few years, and are predicted to increase further.<\/li><\/ul><ul><li>The\nsame is the case with extreme rainfall and drought.<\/li><\/ul><ul><li>Just\nthis year, India experienced an unusually wet August and September. The amount\nof rainfall that September produced was a once-in-a-century event.<\/li><\/ul><ul><li>Other\nsuch extreme events across world:<ul><li>Australia\nis witnessing the hottest december. The heat wave resulted in early bush fires.\nThe average maximum temperature across the country hit 41.9 degrees Celsius.<\/li><\/ul><ul><li>A\ncold wave conditions prevails in northern Afghanistan, Tajikistan, Uzbekistan,\nTurkmenistan and parts of northern Iran.&nbsp;<\/li><\/ul><ul><li>An\nunusual very warm period develops across east-central and southern&nbsp;\nEurope.<\/li><\/ul><ul><li>In\nan another unusual event, a massive patch of water (called as Heat Blob)\nheating up off the eastern coast of New Zealand is attracting the attention of\nweather watchers, and is one of the hottest sea spots on the planet right now.<\/li><\/ul><\/li><\/ul><\/li><li><strong>Western\nDisturbances:&nbsp;<\/strong>Frequent\nwestern disturbances varying from moderate to intense have mainly contributed\nto the severe cold over all of north India this year.<\/li><li>In\naddition, the flow of northwesterly winds over northwest India, that too over\nmuch lower levels, further fuelled the chill factor, making the days much colder\nthan normal during December.<\/li><li>This\nDecember also witnessed haze, fog and rainfall after the passing of each\nwestern disturbance, triggering cold weather conditions over north India.<\/li><li><strong>Low\nClouds:<\/strong>&nbsp;This extended cold spell has\nbeen triggered due to low stratus clouds that are blanketed over a large\ngeographical area between Pakistan, cutting across India and running up to\nBangladesh. Similarly, it is prevailing over a stretch of 500 km to 800 km\nnorth-south, affecting the entire north India.<\/li><\/ul>\n\n\n\n<p><strong>Western Disturbances:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Western\nDisturbance is a frequently used terminology to describe weather in the Indian\nsub-continent.<\/li><li>Western\nDisturbance can be defined as \u201ca low pressure area or a trough over surface or\nthe upper-air in the westerly winds regime, north of 20\u00b0N, causing changes in\npressure, wind pattern and temperature fields. It is accompanied by cloudiness,\nwith or without precipitation.\u201d<\/li><li><strong>Origin:<\/strong>&nbsp;Western Disturbances originate in the Caspian\nSea or the Mediterranean Sea as extra-tropical cyclones. They gradually travel\nacross the middle-east from Iran, Afghanistan and Pakistan to enter the Indian\nsub-continent.<\/li><\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"421\" height=\"273\" src=\"https:\/\/i0.wp.com\/blogadmin.forumias.com\/wp-content\/uploads\/2020\/02\/44.jpg?resize=421%2C273&#038;ssl=1\" alt=\"\" class=\"wp-image-54253\"\/><\/figure>\n\n\n\n<ul class=\"wp-block-list\"><li><strong>Time\nof strong Western disturbances:<\/strong>&nbsp;Though\nWDs move across the Indian region throughout the year, they are in their peak\nduring winter months of January and February. Their effect is minimal during\nthe monsoon months in India.<\/li><li>Western\nDisturbances are the principle rain producing systems during non-monsoonal\nmonths over Northwest India including Punjab, Haryana, Uttar Pradesh and Delhi.\nTheir effect sometime extends up to Gangetic plains and Northeast India.<\/li><li>They\nare also responsible for bringing snowfall in the higher reaches of Jammu &amp;\nKashmir, Himachal Pradesh and Uttarakhand.<\/li><li><strong>Rabi\nCrop:&nbsp;<\/strong>Western Disturbance\nbrings winter and pre-monsoon rain and is important for the development of the\nRabi crop in the Northern subcontinent. Considering that wheat is one of the\nmost important Rabi crops, which is the staple diet of people in this region,\nwinter showers contribute to meet India\u2019s food security.<\/li><li>Weak\nwestern disturbances are associated with crop failure and water problems across\nnorth India.<\/li><\/ul>\n\n\n\n<p><strong>Source:&nbsp;<\/strong><a href=\"https:\/\/indianexpress.com\/article\/explained\/why-this-winter-is-extra-cold-6188129\/\">https:\/\/indianexpress.com\/article\/explained\/why-this-winter-is-extra-cold-6188129\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Context:&nbsp;Cold wave in Northern India. More in news: India Meteorological Department (IMD) issued warning of cold day to severe cold day conditions in many pockets are very likely over Punjab, Haryana, Chandigarh, Delhi and Uttar Pradesh. Dense fog is very likely to engulf Uttar Pradesh, some pockets over Punjab and Haryana, Chandigarh, Delhi and also&hellip; <a class=\"more-link\" href=\"https:\/\/forumias.com\/blog\/7-pm-why-this-winter-is-extra-cold-28th-december-2019\/\">Continue reading <span class=\"screen-reader-text\">7 PM | Why this winter is extra cold| 28th December 2019<\/span><\/a><\/p>\n","protected":false},"author":61,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"footnotes":""},"categories":[130,955,9],"tags":[],"class_list":["post-54252","post","type-post","status-publish","format-standard","hentry","category-7-pm","category-7-pm-brief-infograph","category-public","entry"],"jetpack_featured_media_url":"","views":{"total":0,"cached_at":"","cached_date":1700905757},"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts\/54252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/users\/61"}],"replies":[{"embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/comments?post=54252"}],"version-history":[{"count":0,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/posts\/54252\/revisions"}],"wp:attachment":[{"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/media?parent=54252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/categories?post=54252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/forumias.com\/blog\/wp-json\/wp\/v2\/tags?post=54252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}