{"id":34772,"date":"2025-03-22T10:36:23","date_gmt":"2025-03-22T05:06:23","guid":{"rendered":"https:\/\/www.gujaratweather.com\/?page_id=34772"},"modified":"2025-03-22T10:36:23","modified_gmt":"2025-03-22T05:06:23","slug":"the-second-la-nina-threshold-achieved-at-the-end-of-february-2025-will-it-sustain","status":"publish","type":"page","link":"https:\/\/www.gujaratweather.com\/?page_id=34772","title":{"rendered":"The Second La Ni\u00f1a Threshold Achieved at the End of February 2025 \u2013 Will It Sustain?"},"content":{"rendered":"<div class=\"flex-shrink-0 flex flex-col relative items-end\">\n<div class=\"pt-0\">\n<div class=\"gizmo-bot-avatar flex h-8 w-8 items-center justify-center overflow-hidden rounded-full\">\n<h4 class=\"relative p-1 rounded-sm flex items-center justify-center bg-token-main-surface-primary text-token-text-primary h-8 w-8\">The Second La Ni\u00f1a Threshold Achieved at the End of February 2025 \u2013 Will It Sustain?<\/h4>\n<\/div>\n<\/div>\n<\/div>\n<h4>Enso Status on 5th March 2025<\/h4>\n<h4>Analysis &amp; Commentary by Ashok Patel<\/h4>\n<p>Several international meteorological agencies including the Indian Meteorological Department and various private organization had anticipated the development of a La Ni\u00f1a event during the Indian Summer Monsoon of 2024. However, till end of February, just two La Ni\u00f1a thresholds have been achieved. Having a contrarian view, I had presented a counter perspective through monthly blog posts from July to February 2025. This March post is the latest take on this matter.<\/p>\n<h3>What is a Fully Developed La Ni\u00f1a?<\/h3>\n<p>To understand why the anticipated La Ni\u00f1a did not materialize, it&#8217;s important to define what constitutes a &#8220;fully developed La Ni\u00f1a,&#8221; or a &#8220;full-fledged La Ni\u00f1a,&#8221; based on NOAA\u2019s operational definitions for ENSO (El Ni\u00f1o-Southern Oscillation):<\/p>\n<ul>\n<li><strong>El Ni\u00f1o<\/strong> is characterized by a positive Oceanic Ni\u00f1o Index (ONI) greater than or equal to +0.5\u00baC.<\/li>\n<li><strong>La Ni\u00f1a<\/strong> is defined by a negative ONI less than or equal to -0.5\u00baC.<\/li>\n<\/ul>\n<p>For an event to be classified as a <em>full-fledged<\/em> El Ni\u00f1o or La Ni\u00f1a, the respective ONI threshold must be met or exceeded for at least five consecutive overlapping 3-monthly seasons.<\/p>\n<p>ONI Data has been obtained from CPC &#8211; NWS &#8211; NOAA available <a href=\"https:\/\/origin.cpc.ncep.noaa.gov\/products\/analysis_monitoring\/ensostuff\/ONI_v5.php\">here<\/a><\/p>\n<p>The Ni\u00f1o3.4 SST has been recorded at -0.60\u00b0C for <span style=\"color: #000000;\">December<\/span> 2024 and -0.74\u00b0C for January 2025 and <span style=\"color: #000000;\">-0.59\u00b0C for February <\/span>2025,. This gives the Oceanic Ni\u00f1o Index (ONI) of -0.6\u00b0C for (December-January-February) 2024-25 season, thereby attaining the Second La Nina threshold at the end of February 2025.<\/p>\n<p>This development has potentially set the stage for a fully developed La Ni\u00f1a by May 2025, provided that La Ni\u00f1a thresholds are sustained across all overlapping three-month seasons until then. However, the presence of unusually warm Ni\u00f1o1.2 and Ni\u00f1o3 SST anomalies raises the possibility that the La Ni\u00f1a threshold may only be exceeded for four or fewer consecutive overlapping three-month seasons. If this happens, the developing La Ni\u00f1a could collapse, and historically, such an event would be classified as ENSO-neutral.<\/p>\n<p>If La Ni\u00f1a fails to materialize, a reclassification of ENSO status cannot be ruled out due to potential adjustments in sea surface temperature (SST) norms for the Ni\u00f1o regions, based on the 1996\u20132025 base period. The CPC updates this 30-year base period every five years, with the next revision scheduled for early 2026.<\/p>\n<p><strong style=\"font-size: 1.5rem;\">How ONI is determined:<\/strong><\/p>\n<p>The ONI is based on SST departures from average in the Ni\u00f1o 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO. Defined as the three-month running-mean SST departures in the Ni\u00f1o 3.4 region. Departures are based on a set of improved homogeneous historical SST analyses (Extended Reconstructed SST \u2013 ERSST.v5).<\/p>\n<p>In real-time operations, the past 30-year base period (e.g. 1991\u20132020) will continue to be used to compute the departure from average. However, CPC will create an additional 30-year base period every 5 years (the next update will be at the beginning of 2026). When these 5 year updates occur, the ONI values over the most recent decade will change slightly because of the inclusion of more recent data. Every five years, this method takes care of climatological changes in the SST of Nino3.4 region and the buzz about the need to adopt Relative Nino Index is not justified.<\/p>\n<p>NOAA Operational Definitions for El Ni\u00f1o and La Ni\u00f1a, El Ni\u00f1o: characterized by a positive ONI greater than or equal to +0.5\u00baC. La Ni\u00f1a: characterized by a negative ONI less than or equal to -0.5\u00baC. By historical standards, to be classified as a full-fledged El Ni\u00f1o or La Ni\u00f1a episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.<\/p>\n<p>CPC considers El Ni\u00f1o or La Ni\u00f1a conditions to occur when the monthly Ni\u00f1o3.4 OISST departures meet or exceed +\/- 0.5\u00baC along with consistent atmospheric features. These anomalies must also be forecast to persist for 3 consecutive months.<\/p>\n<p>The\u00a0<b>Climate Prediction Center<\/b>\u00a0(<b>CPC<\/b>) is a United States Federal Agency that is one of the NECP, which are a part of the NOAA<\/p>\n<h4 style=\"text-align: center;\"><strong>Latest Oceanic Nino Index Graph Shows Two La Nina Threshold<br \/>\nAchieved\u00a0 At The End Of February 2025<\/strong><\/h4>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/www.gujaratweather.com\/?attachment_id=34669#main\" rel=\"attachment wp-att-34669\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-34669\" src=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/ONI_DJF_2025e-1024x677.jpg\" alt=\"\" width=\"860\" height=\"569\" srcset=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/ONI_DJF_2025e-1024x677.jpg 1024w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/ONI_DJF_2025e-300x198.jpg 300w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/ONI_DJF_2025e-768x508.jpg 768w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/ONI_DJF_2025e.jpg 1249w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>The Table below shows the monthly SST of Nino3.4 Region and the Climate adjusted normal SST and SST anomaly from February 2023 to February 2025. Climate Base 1991-2020. ERSST.v5<\/strong><\/p>\n<pre>Period    Nino3.4 ClimAdjust\r\nYR   MON  Temp.\u00baC Temp.\u00baC ANOM \u00baC\r\n\r\n\r\n2023   2   26.30   26.76   -0.46\r\n2023   3   27.19   27.29   -0.11\r\n2023   4   27.96   27.83    0.14\r\n2023   5   28.40   27.94    0.46\r\n2023   6   28.57   27.73    0.84\r\n2023   7   28.31   27.29    1.02\r\n2023   8   28.21   26.86    1.35\r\n2023   9   28.32   26.72    1.60\r\n2023  10   28.44   26.72    1.72\r\n2023  11   28.72   26.70    2.02\r\n2023  12   28.63   26.60    2.02\r\n2024   1   28.37   26.55    1.82\r\n2024   2   28.28   26.76    1.52\r\n2024   3   28.42   27.29    1.12\r\n2024   4   28.60   27.83    0.78\r\n2024   5   28.17   27.94    0.24\r\n2024   6   27.91   27.73    0.18\r\n2024   6   27.90   27.73    0.17\r\n2024   7   27.34   27.29    0.05\r\n2024   8   26.74   26.86   -0.12\r\n2024   9   26.46   26.72   -0.26\r\n2024  10   26.45   26.72   -0.27\r\n2024  11   26.46   26.70   -0.25\r\n2024  12   26.00   26.60   -0.60\r\n2025   1   25.81   26.55   -0.74\r\n2025   2   26.17   26.76   -0.59\r\n<\/pre>\n<p><strong>Indications and analysis of various International Weather\/Climate agencies monitoring Enso conditions is depicted hereunder:<\/strong><\/p>\n<h4><strong>Summary by: Climate Prediction Center \/ NCEP \u00a0Dated 3rd February 2025<\/strong><\/h4>\n<p><strong>ENSO Alert System Status: La Ni\u00f1a Advisory<\/strong><\/p>\n<p><strong>La Ni\u00f1a conditions are present.*<\/strong><br \/>\nEquatorial sea surface temperatures (SSTs) are near-to-below average in the central and east-central Pacific Ocean. SSTs are above-average in the eastern Pacific Ocean.<br \/>\nLa Ni\u00f1a conditions are expected to persist in the near-term, with a transition to ENSO-neutral likely during March-May 2025 (66% chance).<\/p>\n<p>Note: Statements are updated once a month (2nd Thursday of each month) in association with the ENSO Diagnostics Discussion, which can be found by clicking <a style=\"font-size: 1.5rem;\" href=\"http:\/\/www.cpc.ncep.noaa.gov\/products\/analysis_monitoring\/enso_advisory\">here<\/a><span style=\"font-size: 1.5rem;\">.<\/span><\/p>\n<h4><\/h4>\n<h4><strong>Recent (preliminary) Southern Oscillation Index values as per The Long Paddock &#8211; Queensland Government.<\/strong><\/h4>\n<p>The 30 Days average SOI for end of February 2025 was at 7.14, however, on 4th March 2025 it has decreased and is in the neutral zone at +5.7 as per The Long Paddock &#8211; Queensland Government. The 90 Days average SOI has decrease to +5.79 on 4th March 2025. Currently, both 30 Days as well as the 90 Days average SOI is on a declining trend.<\/p>\n<p><a href=\"https:\/\/www.gujaratweather.com\/?attachment_id=34650#main\" rel=\"attachment wp-att-34650\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-34650\" src=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/Long-Paddock-SOI-040325-1024x427.png\" alt=\"\" width=\"860\" height=\"359\" srcset=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/Long-Paddock-SOI-040325-1024x427.png 1024w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/Long-Paddock-SOI-040325-300x125.png 300w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/Long-Paddock-SOI-040325-768x320.png 768w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/Long-Paddock-SOI-040325.png 1200w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<h4><strong>As per BOM \u2013 Australia 5th March 2025<\/strong><\/h4>\n<ul>\n<li>The El Ni\u00f1o\u2013Southern Oscillation (ENSO) remains neutral despite a brief period from December to February when the tropical Pacific shifted towards a La Ni\u00f1a-like state. SSTs in the central tropical Pacific have risen over the past 4 weeks, with the most recent value of Ni\u00f1o3.4 (\u22120.30 \u00b0C for the week ending 2 March) firmly within the neutral range.<\/li>\n<li>The Bureau&#8217;s model predicts neutral ENSO (neither El Ni\u00f1o nor La Ni\u00f1a) until at least July. This is consistent with all surveyed international models.<\/li>\n<li style=\"list-style-type: none;\"><a href=\"https:\/\/www.gujaratweather.com\/?attachment_id=34651#main\" rel=\"attachment wp-att-34651\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-large wp-image-34651\" src=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/nino3_4-BOM-1024x683.png\" alt=\"\" width=\"860\" height=\"574\" srcset=\"https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/nino3_4-BOM-1024x683.png 1024w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/nino3_4-BOM-300x200.png 300w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/nino3_4-BOM-768x512.png 768w, https:\/\/www.gujaratweather.com\/wp-content\/uploads\/2025\/03\/nino3_4-BOM.png 1500w\" sizes=\"auto, (max-width: 860px) 100vw, 860px\" \/><\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>The Second La Ni\u00f1a Threshold Achieved at the End of February 2025 \u2013 Will It Sustain? Enso Status on 5th March 2025 Analysis &amp; Commentary by Ashok Patel Several international meteorological agencies including the Indian Meteorological Department and various private <a class=\"more-link\" href=\"https:\/\/www.gujaratweather.com\/?page_id=34772\">Read More &#8230;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-34772","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=\/wp\/v2\/pages\/34772","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=34772"}],"version-history":[{"count":0,"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=\/wp\/v2\/pages\/34772\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.gujaratweather.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=34772"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}