{"id":56333,"date":"2024-01-06T23:59:00","date_gmt":"2024-01-06T23:59:00","guid":{"rendered":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=56333"},"modified":"2024-01-08T04:47:49","modified_gmt":"2024-01-08T04:47:49","slug":"foehn-gap-and-orographic-crest-cloud-downwind-of-the-sierra-nevada","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/56333","title":{"rendered":"Foehn gap and orographic crest cloud downwind of the Sierra Nevada"},"content":{"rendered":"

<\/a>

GOES-18 Mid-level Water Vapor (6.9 \u00b5m) images, with pilot report (PIREP) plots of turbulence [click to play animated GIF | MP4<\/strong><\/a>]<\/p><\/div>GOES-18 (GOES-West)<\/em> Mid-level Water Vapor (6.9 \u00b5m<\/strong><\/a>) images\u00a0(above)<\/strong><\/em> revealed a well-defined Foehn gap (narrow ribbon of darker blue enhancement) near the spine of the Sierra Nevada range in California, along with a broad “orographic crest cloud” (darker green enhancement) that extended eastward across southeast California into southern Nevada on 06 January 2024<\/strong><\/a>.<\/p>\n

The corresponding GOES-18 “Clean” Infrared Window (10.3 \u00b5m<\/strong><\/a>) images are shown below.<\/p>\n

<\/a>

GOES-18 “Clean” Infrared Window (10.3 \u00b5m) images, with pilot report (PIREP) plots of turbulence [click to play animated GIF | MP4<\/strong><\/a>]<\/p><\/div>A toggle between GOES-18 Water Vapor and Infrared images at 2201 UTC + Topography (below)<\/strong><\/em> helped to illustrate that the location of the Foehn gap was immediately downwind (east) of the spine of the Sierra Nevada.<\/p>\n

<\/a>

GOES-18 Water Vapor and Infrared images at 2201 UTC + Topography [click to enlarge]<\/p><\/div>There were Pilot Reports of Mountain Waves in the vicinity of the Foehn gap, as well as a report of Moderate to Severe Turbulence within the crest cloud feature (below)<\/strong><\/em>.<\/p>\n

<\/a>

GOES-18 Water Vapor image at 2106 UTC, with a Pilot Report of a Mountain Wave at 2105 UTC [click to enlarge]<\/p><\/div>
\n

<\/a>

GOES-18 Water Vapor image at 2131 UTC, with a Pilot Report of a Mountain Wave at 2131 UTC [click to enlarge]<\/p><\/div>
\n

<\/a>

GOES-18 Water Vapor image at 2206 UTC, with a Pilot Report of Moderate to Severe Turbulence at 2208 UTC [click to enlarge]<\/p><\/div>In a comparison of GOES-18 10.3 \u00b5m infrared brightness temperature, CLAVR-x<\/strong><\/a> Cloud Top Temperature derived product and CLAVR-x Cloud Top Height derived product within the crest cloud feature at 0021 UTC (below)<\/em><\/strong>, the Cloud Top Temperature product was nearly 5C colder than the single-channel infrared brightness temperature, and the Cloud Top Height was around 45000 ft.<\/p>\n

<\/a>

Cursor sample of GOES-18 10.3 \u00b5m brightness temperature (white), CLAVR-x Cloud Top Temperature derived product (cyan) and CLAVR-x Cloud Top Height derived product (green) at 0021 UTC [click to enlarge]<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

GOES-18 (GOES-West) Mid-level Water Vapor (6.9 \u00b5m) images\u00a0(above) revealed a well-defined Foehn gap (narrow ribbon of darker blue enhancement) near the spine of the Sierra Nevada range in California, along with a broad “orographic crest cloud” (darker green enhancement) that extended eastward across southeast California into southern Nevada on 06 January 2024. The corresponding GOES-18 […]<\/p>\n","protected":false},"author":18,"featured_media":56340,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[21,63,114],"tags":[],"class_list":["post-56333","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-aviation","category-clavrx","category-goes-18"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/56333","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=56333"}],"version-history":[{"count":6,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/56333\/revisions"}],"predecessor-version":[{"id":56339,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/56333\/revisions\/56339"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/56340"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=56333"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=56333"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=56333"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}