{"id":17027,"date":"2014-10-21T12:59:00","date_gmt":"2014-10-21T12:59:00","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=17027"},"modified":"2014-10-22T22:47:01","modified_gmt":"2014-10-22T22:47:01","slug":"hurricane-ana-south-of-hawaii-2","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/17027","title":{"rendered":"Hurricane Ana south of Hawai’i"},"content":{"rendered":"
\"Advanced<\/a>

Advanced Dvorak Technique (ADT) intensity estimate plot for Ana<\/p><\/div>\n

A plot of the Advanced Dvorak Technique (ADT<\/strong><\/a>) intensity estimate for Ana (above)<\/strong><\/em> shows that the strength of the tropical cyclone fluctuated during its multi-day lifetime (storm track<\/strong><\/a>), initially becoming a strong Tropical Storm on 15 October, weakening on 16 October, and then slowly intensifying into a Category 1 Hurricane. A sequence of Suomi NPP VIIRS 11.45 \u00b5m IR channel images (below; click image to play animation)<\/strong><\/em> shows Ana at various stages during the 15-21 October period; the coldest cloud-top IR brightness temperature seen was -95\u00ba C at 00:40 UTC on 19 October.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS 11.45 \u00b5m IR channel images (click to play animation)<\/p><\/div>\n

After prior testing<\/strong><\/a> of additional Rapid Scan Operations (RSO) capabilities, the GOES-15 satellite was placed into RSO mode over the Hawai’i region to monitor Ana. During the 17-19 October period that Ana was classified as a Hurricane, GOES-15 10.7 \u00b5m IR channel images (below; click image to play a 75 MB animated GIF; also available as an MP4 movie file<\/a>)<\/strong><\/em> revealed a number of robust convective bursts, with some exhibiting cloud-top IR brightness temperatures in the -80 to -85\u00ba C range (violet color enhancement)<\/em>. This was the first operational implementation of GOES-West RSO imagery over the Hawai’i region since the early 1990s, and the higher frequency of images — 8 images per hour, instead of the routine 4 images per hour — proved to be helpful for monitoring Ana (CPHC forecast discussion<\/strong><\/a>).<\/p>\n

Longer-term animations of GOES-15 RSO imagery covering the lifetime of Ana are available in YouTube format (IR<\/strong><\/a> | visible<\/strong><\/a>). Much of the Hawaiian Islands received heavy rain<\/strong><\/a>, with amounts in excess of 11 inches reported on Hawai’i and Oahu.<\/p>\n

\"GOES-15<\/a>

GOES-15 10.7 \u00b5m IR channel images (click to play animated GIF)<\/p><\/div>\n

Even after Ana was downgraded to a Tropical Storm early on 20 October, a Suomi NPP VIIRS 11.45 \u00b5m IR image showed that cloud-top IR brightness temperatures were still as cold as -90\u00ba C (yellow pixels within the violet-enhanced cloud tops)<\/em>. Also note the presence of cloud-top gravity waves propagating outward away from the storm center.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS 11.45 \u00b5m IR channel image, with overlays of surface analysis and surface observations<\/p><\/div>\n

Late in the day on 20 October, GOES-15 0.63 \u00b5m visible channel images (below; click to play animation; also available as an MP4 movie file<\/a>)<\/strong><\/em> revealed that the Low-Level Circulation Center (LLCC) of Ana became exposed as it moved to the southwest from beneath the canopy of deep convective cloud tops. This was a result of moderate southwesterly deep-layer wind shear<\/strong><\/a> across the region.<\/p>\n

\"GOES-15<\/a>

GOES-15 0.63 \u00b5m visible channel images (click to play animation)<\/p><\/div>\n

During the following night, the exposed LLCC was still very apparent on a Suomi NPP VIIRS 0.7 \u00b5m Day\/Night Band image at 12:30 UTC or 2:30 am local time (below)<\/em><\/strong>.<\/p>\n

\"Suomi<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

A plot of the Advanced Dvorak Technique (ADT) intensity estimate for Ana (above) shows that the strength of the tropical cyclone fluctuated during its multi-day lifetime (storm track), initially becoming a strong Tropical Storm on 15 October, weakening on 16 October, and then slowly intensifying into a Category 1 Hurricane. A sequence of Suomi NPP […]<\/p>\n","protected":false},"author":18,"featured_media":17030,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[43,16,49,2,48],"tags":[],"class_list":["post-17027","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-goes-15","category-heavy-rain-flooding","category-suomi_npp","category-tropical-cyclones","category-viirs"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17027","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=17027"}],"version-history":[{"count":13,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17027\/revisions"}],"predecessor-version":[{"id":17042,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/17027\/revisions\/17042"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/17030"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=17027"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=17027"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=17027"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}