{"id":47385,"date":"2025-05-27T10:35:14","date_gmt":"2025-05-27T05:05:14","guid":{"rendered":"https:\/\/vajiramandravi.com\/current-affairs\/?p=47385"},"modified":"2025-05-27T11:50:27","modified_gmt":"2025-05-27T06:20:27","slug":"why-the-monsoon-arrived-early-in-india-this-year-key-factors-explained","status":"publish","type":"post","link":"https:\/\/vajiramandravi.com\/current-affairs\/why-the-monsoon-arrived-early-in-india-this-year-key-factors-explained\/","title":{"rendered":"Why the Monsoon Arrived Early in India This Year: Key Factors Explained"},"content":{"rendered":"<h2>Early Monsoon Onset India Latest News<\/h2>\n<ul>\n<li>The IMD declared monsoon onset over Kerala on May 24, eight days earlier than the normal June 1 schedule. This onset signals the start of the June\u2013September southwest monsoon, which delivers over 70% of India&#8217;s annual rainfall, making it vital for agriculture and the economy.<\/li>\n<li>The last time the monsoon arrived this early was in 2009, on May 23.<\/li>\n<\/ul>\n<h2>Monsoon Onset Declaration: Criteria and Process<\/h2>\n<ul>\n<li>The IMD attempts to declare the schedule for southwest monsoon onset any time after May 10. To do so, certain essential criteria are considered.<\/li>\n<\/ul>\n<h3>Key Criteria for Onset<\/h3>\n<ul>\n<li><strong>Rainfall<\/strong>\n<ul>\n<li>At least 60% of 14 designated southern meteorological stations (including Thiruvananthapuram, Kochi, Mangalore, etc.) must report \u22652.5 mm rainfall for two consecutive days.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Wind Field<\/strong>\n<ul>\n<li>Westerly winds must dominate up to 600 hPa pressure level.<\/li>\n<li>Wind speed at 925 hPa must range between 15\u201320 knots (27\u201337 km\/h).<\/li>\n<\/ul>\n<\/li>\n<li><strong>Outgoing Longwave Radiation (OLR)<\/strong>\n<ul>\n<li>The Earth absorbs and reflects solar energy, affecting global temperature and climate.<\/li>\n<li>Aerosol particles in the atmosphere can absorb sunlight, contributing to atmospheric warming.<\/li>\n<li>The absorbed energy is re-emitted as longwave infrared radiation (OLR).<\/li>\n<li>OLR mainly originates from the warmed upper atmosphere, with some from the Earth&#8217;s surface.<\/li>\n<li>This radiation helps warm the lower atmosphere, which in turn warms the Earth\u2019s surface.<\/li>\n<li>OLR values must be below 200 W\/m\u00b2, indicating favorable atmospheric conditions for monsoon onset.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h3>IMD Declaration<\/h3>\n<ul>\n<li>The monsoon onset is declared on the second day after all above conditions are met.<\/li>\n<\/ul>\n<h3>This Year\u2019s Onset<\/h3>\n<ul>\n<li>A simultaneous onset occurred over Kerala, Lakshadweep, Mahe (Puducherry), parts of the Arabian Sea, Bay of Bengal, and southern Karnataka and Mizoram.<\/li>\n<\/ul>\n<h2>Factors Behind Early Monsoon Onset in India<\/h2>\n<ul>\n<li>The early onset of the southwest monsoon was driven by favourable atmospheric and oceanic conditions.\u00a0<\/li>\n<li>A low-pressure area over the Arabian Sea and a trough over Vidarbha enhanced moisture inflow and atmospheric convection, accelerating the monsoon\u2019s advance.<\/li>\n<\/ul>\n<h3>Madden-Julian Oscillation (MJO)<\/h3>\n<ul>\n<li>MJO is a significant and complex ocean-atmosphere phenomenon that originates in the Indian Ocean and plays a crucial role in influencing the Indian monsoon.\u00a0<\/li>\n<li>It involves disturbances in clouds, winds, and pressure that move eastward at a speed of 4\u20138 metres per second.\u00a0<\/li>\n<li>These disturbances, known as MJO wind bands, can circle the globe within 30 to 60 days and lead to major weather changes along their path.<\/li>\n<li>When the MJO is in a favourable phase, it can enhance rainfall over India during the monsoon season.<\/li>\n<\/ul>\n<h3>Mascarene High<\/h3>\n<ul>\n<li>The IMD describes the Mascarene High as a high-pressure area found around the Mascarene Islands (in the south Indian Ocean) during the monsoon period.\u00a0<\/li>\n<li>The variation in the intensity of high pressure is responsible for heavy rains along India\u2019s west coast.<\/li>\n<\/ul>\n<h3>Convection and Rainfall<\/h3>\n<ul>\n<li>An increase in convective activity\u2014vertical movement of heat and moisture in the atmosphere\u2014can lead to rainfall.\u00a0<\/li>\n<li>For example, a convective system over Haryana recently moved southeastward and caused rain in the Delhi region.<\/li>\n<\/ul>\n<h3>Somali Jet and Monsoon Strength<\/h3>\n<ul>\n<li>The Somali jet is a low-level, cross-equatorial wind system originating near Mauritius and north Madagascar.\u00a0<\/li>\n<li>By May, it crosses the east coast of Africa and reaches the Arabian Sea and the west coast of India.\u00a0<\/li>\n<li>A strong Somali jet enhances the monsoon winds, contributing to a robust monsoon.<\/li>\n<\/ul>\n<h3>Heat-Low and Moisture Inflow<\/h3>\n<ul>\n<li>With the Sun\u2019s shift to the northern hemisphere during summer, a low-pressure zone forms over the Arabian Sea.\u00a0<\/li>\n<li>A heat-low over Pakistan and nearby regions acts like a suction pump, drawing moist air into the monsoon trough and intensifying monsoon rainfall.<\/li>\n<\/ul>\n<h3>Monsoon Trough<\/h3>\n<ul>\n<li>The monsoon trough is an elongated low-pressure area stretching from the heat low over northwest India to the north Bay of Bengal.\u00a0<\/li>\n<li>Its north-south oscillation brings rainfall across the core monsoon zone during June to September.\u00a0<\/li>\n<li>Additionally, the pressure gradient and the monsoon onset vortex\u2014a cyclonic system in the Arabian Sea\u2014contribute to the timely and strong onset of the monsoon.<\/li>\n<\/ul>\n<h2>Early Monsoon Onset India FAQs<\/h2>\n<p><strong>Q1.<\/strong>\u00a0When did the 2025 monsoon begin in India?<\/p>\n<p><strong>Ans.<\/strong>\u00a0On May 24, eight days earlier than the normal onset date of June 1.<\/p>\n<p><strong>Q2.<\/strong>\u00a0What is the Madden-Julian Oscillation (MJO)?<\/p>\n<p><strong>Ans.<\/strong>\u00a0A global weather system that enhances rainfall when in a favourable phase over the Indian Ocean.<\/p>\n<p><strong>Q3.<\/strong>\u00a0How does the Somali Jet affect monsoons?<\/p>\n<p><strong>Ans.<\/strong>\u00a0A strong Somali Jet enhances monsoon winds, boosting rainfall along India\u2019s west coast.<\/p>\n<p><strong>Q4.<\/strong>\u00a0What is the role of the heat-low?<\/p>\n<p><strong>Ans.<\/strong>\u00a0It draws moist air from the sea into the land, strengthening the monsoon trough.<\/p>\n<p><strong>Q5.<\/strong>\u00a0Why is OLR important for monsoon onset?<\/p>\n<p><strong>Ans.<\/strong>\u00a0Low OLR values (&lt;200 W\/m\u00b2) indicate atmospheric conditions favorable for monsoon development.<\/p>\n<p>.<strong>Source:\u00a0<\/strong><a href=\"https:\/\/indianexpress.com\/article\/explained\/explained-climate\/early-monsoon-onset-india-reason-factors-meaning-10027688\/\" target=\"_blank\" rel=\"nofollow noopener\">IE<\/a>\u00a0|\u00a0<a href=\"https:\/\/www.cnbctv18.com\/photos\/india\/explained-why-is-the-monsoon-early-this-year-19610746-2.htm\" target=\"_blank\" rel=\"nofollow noopener\">CNBCTV18<\/a>\u00a0|\u00a0<a href=\"https:\/\/timesofindia.indiatimes.com\/india\/monsoon-arrives-early-in-india-heres-what-caused-the-unusual-shift\/articleshowprint\/121392043.cms\" target=\"_blank\" rel=\"nofollow noopener\">ToI<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Explore why the 2025 southwest monsoon arrived early in India. Learn about MJO, Somali Jet, convection, and other contributing factors.<\/p>\n","protected":false},"author":8,"featured_media":47402,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[18],"tags":[430,60,22,59],"class_list":{"0":"post-47385","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-upsc-mains-current-affairs","8":"tag-early-monsoon-onset-india","9":"tag-mains-articles","10":"tag-upsc-current-affairs","11":"tag-upsc-mains-current-affairs","12":"no-featured-image-padding"},"acf":[],"_links":{"self":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/47385","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/comments?post=47385"}],"version-history":[{"count":0,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/posts\/47385\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media\/47402"}],"wp:attachment":[{"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/media?parent=47385"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/categories?post=47385"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vajiramandravi.com\/current-affairs\/wp-json\/wp\/v2\/tags?post=47385"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}