{"id":70538,"date":"2026-05-18T23:59:00","date_gmt":"2026-05-18T23:59:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=70538"},"modified":"2026-05-21T03:27:38","modified_gmt":"2026-05-21T03:27:38","slug":"1-minute-goes-18-imagery-to-monitor-flash-flooding-potential-across-american-samoa-2","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/70538","title":{"rendered":"1-minute GOES-18 imagery to monitor flash flooding potential across American Samoa"},"content":{"rendered":"<p><div style=\"width: 3034px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260518_goes18_infrared_NSTU.mp4\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260519_0018utc_goes18_infrared_NSTU.png\" width=\"3024\" height=\"1790\" \/><\/a><p class=\"wp-caption-text\">1-minute GOES-18 Infrared Window (10.3 \u00b5m) images centered on Pago Pago (NSTU), from 1910 UTC on 18 May to 0200 UTC on 19 May [click to play MP4 animation]<\/p><\/div>During a period when American Samoa had been under a Flash Flood Watch, the Weather Service Office at <a href=\"https:\/\/www.weather.gov\/ppg\/?lang=english]\"><strong>Pago Pago<\/strong><\/a> requested that a GOES-18 (GOES-West) <a href=\"https:\/\/www.nco.ncep.noaa.gov\/status\/satellite\/\"><strong>Mesoscale Domain Sector<\/strong><\/a> be positioned over the region &#8212; due to their lack of radar, satellite imagery can be a critical tool for monitoring the development of deep convection. 1-minute GOES-18 Infrared imagery <strong><em>(above)<\/em><\/strong> showed clusters of deep convection that moved across the main island of Tutuila during a 7-hour period on 18-19 May 2026. At the Pago Pago METAR site on Tutuila (NSTU), most of their calendar day 24-hour precipitation for 18 May (<a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260518_NSTU_decoded_observations.png\"><strong>5.21 inches<\/strong><\/a>) occurred in a 3-hour period during the GOES-18 animation shown above \u2014 and several <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260518_NSTU_ffw.text\"><strong>Flash Flood Warnings<\/strong><\/a> were issued amid a variety of <a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260519_NSTU_lsr.text\"><strong>Local Storm Reports<\/strong><\/a> of flooding.<\/p>\n<p>As a small cluster of convection rapidly developed just west of Tutuila around 0000 UTC on 19 May, an overshooting top exhibited an infrared brightness temperature of -80.4\u00baC at 0018 UTC <em><strong>(below)<\/strong><\/em>. This convective cluster then produced a thunderstorm with heavy rain showers at Pago Pago during the 0100-0200 UTC time period (<a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260518_NSTU_metar_observations.png\"><strong>METAR observations<\/strong><\/a>), contributing to much of the 4.15&#8243; of rainfall that occurred in the 3-hour period ending at 0300 UTC.<\/p>\n<div style=\"width: 3258px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260519_0018utc_goes18_infrared_NSTU_cursor_sample.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium\" src=\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/images\/2026\/05\/260519_0018utc_goes18_infrared_NSTU_cursor_sample.png\" width=\"3248\" height=\"2122\" \/><\/a><p class=\"wp-caption-text\">GOES-18 Infrared Window (10.3 \u00b5m) image at 0018 UTC on 19 May, with a cursor probe of an overshooting top infrared brightness temperature [click to enlarge]<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>During a period when American Samoa had been under a Flash Flood Watch, the Weather Service Office at Pago Pago requested that a GOES-18 (GOES-West) Mesoscale Domain Sector be positioned over the region &#8212; due to their lack of radar, satellite imagery can be a critical tool for monitoring the development of deep convection. 1-minute [&hellip;]<\/p>\n","protected":false},"author":18,"featured_media":70539,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[114,16],"tags":[],"class_list":["post-70538","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-18","category-heavy-rain-flooding"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/70538","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/users\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/comments?post=70538"}],"version-history":[{"count":10,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/70538\/revisions"}],"predecessor-version":[{"id":70543,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/70538\/revisions\/70543"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/70539"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=70538"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=70538"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=70538"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}