{"id":37380,"date":"2020-06-30T23:59:11","date_gmt":"2020-06-30T23:59:11","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=37380"},"modified":"2025-08-01T15:52:45","modified_gmt":"2025-08-01T15:52:45","slug":"actinoform-clouds-near-hawaii","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/37380","title":{"rendered":"Actinoform clouds near Hawai’i"},"content":{"rendered":"

\"GOES-17<\/a>

GOES-17 \u201cRed\u201d Visible (0.64 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>GOES-17 (GOES-West)<\/em> \u201cRed\u201d Visible (0.64 \u00b5m<\/strong><\/a>) images (above)<\/strong> <\/em>revealed 3 cyclonically-rotating actinoform cloud<\/strong><\/a> structures that were moving west-southwestward toward the Hawaiian Islands on 30 June 2020 (surface analyses<\/strong><\/a>).<\/p>\n

A closer look at the northernmost actinoform feature showed it moving over Buoy 51000<\/strong><\/a> (located 245 miles northeast of Honolulu) around 04 UTC on 01 July — there was somewhat of an increase in 1-minute wind speeds<\/strong><\/a> and wind gusts<\/strong><\/a> as it approached, but no obvious perturbation was seen in the air pressure<\/strong><\/a> (it appeared to have arrived during the typical ~12-hourly drop in pressure).<\/p>\n

\"GOES-17<\/a>

GOES-17 \u201cRed\u201d Visible (0.64 \u00b5m)<\/em> images [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>A sequence of three hourly (at 0010, 0110 and 0210 UTC) panoramic camera views from Buoy 51000 (below)<\/strong><\/em> suggested that there were rain showers reaching the ocean surface beneath one of the actinoform’s radial arms at 0210 UTC (GOES-17 Visible image<\/a><\/strong>).<\/p>\n

\"Sequence<\/a>

Sequence of three hourly panoramic camera views from Buoy 51000 —\u00a0 at 0010, 0110 and 0210 UTC [click to enlarge]<\/p><\/div>True Color Red-Green-Blue (RGB) and Infrared Window (11.45 \u00b5m) VIIRS images from NOAA-20 and Suomi NPP as visualized using RealEarth<\/strong><\/a> (below)<\/strong><\/em> provided a detailed view of 2 of the actinoform clouds. The radial arms that comprised the cloud features remained within the marine boundary layer, so they exhibited fairly warm cloud-top infrared brightness temperatures.<\/p>\n

\"True<\/a>

True Color RGB and Infrared Window (11.45 \u00b5m)<\/em> images from NOAA-20 and Suomi NPP [click to enlarge]<\/p><\/div>Plots of rawinsonde data<\/strong><\/a> from Hilo, Hawai’i (below)<\/strong><\/em> indicated that the marine boundary layer was strongly capped by a temperature inversion at an altitude of 1.3-1.5 km (where the air temperature was around +15\u00baC — which was very close to the minimum cloud-top infrared brightness temperatures exhibited by the actinoform clouds).<\/p>\n

\"Plots<\/a>

Plots of rawinsonde data from Hilo, Hawai’i [click to enlarge]<\/p><\/div>Other examples of actinoform clouds have been shown in May 2019<\/strong><\/a>, March 2008<\/strong><\/a>, March 2007<\/strong><\/a> and June 1997<\/strong><\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

GOES-17 (GOES-West) \u201cRed\u201d Visible (0.64 \u00b5m) images (above) revealed 3 cyclonically-rotating actinoform cloud structures that were moving west-southwestward toward the Hawaiian Islands on 30 June 2020 (surface analyses). A closer look at the northernmost actinoform feature showed it moving over Buoy 51000 (located 245 miles northeast of Honolulu) around 04 UTC on 01 July — […]<\/p>\n","protected":false},"author":18,"featured_media":37382,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[80,8,78,53,45,49,48],"tags":[],"class_list":["post-37380","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-17","category-marine-weather","category-noaa-20","category-real-earth","category-redgreenblue-rgb-images","category-suomi_npp","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37380","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=37380"}],"version-history":[{"count":12,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37380\/revisions"}],"predecessor-version":[{"id":66161,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/37380\/revisions\/66161"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/37382"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=37380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=37380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=37380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}