{"id":7745,"date":"2011-03-30T23:59:18","date_gmt":"2011-03-30T23:59:18","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=7745"},"modified":"2011-03-31T19:35:46","modified_gmt":"2011-03-31T19:35:46","slug":"mid-tropospheric-gravity-waves-upwind-of-intense-convection","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/7745","title":{"rendered":"Mid-tropospheric gravity waves upwind of intense convection"},"content":{"rendered":"
\"GOES-13<\/a>

GOES-13 6.5 \u00c2\u00b5m water vapor images (click image to play animation)<\/p><\/div>\n

McIDAS images of 4-km resolution GOES-13 6.5 \u00c2\u00b5m water vapor channel data (above; click image to play animation)<\/em><\/strong> showed a well-defined warm\/dry “arc” feature (denoted by the brighter yellow color enhancement)<\/em> just upwind of a large Mesoscale Convective System (MCS) that was moving eastward along the northern Gulf of Mexico and the adjacent Gulf Coast states on 30 March 2011<\/strong><\/a>. The MCS eventually produced a number of reports of damaging winds, large hail, and tornadoes<\/a><\/strong> across northern Florida. Also note that a subtle signature of what appeared to be gravity waves could be seen within portions of this warm\/dry arc feature (especially in the southern portion, over the Gulf of Mexico)<\/em>.<\/p>\n

AWIPS images of 1-km resolution MODIS 6.7 \u00c2\u00b5m water vapor channel data (below)<\/em><\/strong> offered a more detailed view of the packet of gravity waves that was associated with the southern portion of the dry arc feature. This warm\/dry arc seen on the water vapor imagery could have been a signature of a region of strong compensating subsidence along the rear edge of the intense deep convection.<\/p>\n

\"MODIS<\/a>

MODIS 6.7 \u00c2\u00b5m water vapor images<\/p><\/div>\n

A number of pilot reports of moderate turbulence were co-located within this warm\/dry arc feature seen on the water vapor imagery (below; click image to play animation),<\/em><\/strong> especially around 14 UTC<\/a><\/strong>, 16 UTC<\/a><\/strong>, and 17 UTC<\/a><\/strong>. There was also a report of severe turbulence<\/strong><\/a> along the northern portion of the arc feature as it moved over far southern Alabama at 17:35 UTC. This supports the idea that the warm\/dry arc was likely a signature of strong subsidence in the wake of the MCS.<\/p>\n

\"GOES-13<\/a>

GOES-13 6.5 \u00c2\u00b5m water vapor images + pilot reports of turbulence (click to play animation)<\/p><\/div>\n

Note that a small patch of clouds developed along the southern portion of the warm\/dry arc which contained the gravity waves over the Gulf of Mexico after about 18 UTC — additional information about this cloud patch could offer some clues as to the approximate altitude of the gravity waves. The POES AVHRR Cloud Type product (below)<\/em><\/strong> indicated that the cloud patch associated with the gravity wave was a cirrus feature (orange color enhancement)<\/em>.<\/p>\n

\"POES<\/a>

POES AVHRR Cloud Type product<\/p><\/div>\n

The corresponding POES AVHRR Cloud Top Height product (below)<\/em><\/strong> suggested that the tops of that cloud patch were generally in the 12-13 km range (darker green color enhancement)<\/em>. POES AVHRR cloud top temperatures<\/strong><\/a> were in the -55 to -65\u00c2\u00ba C range with this feature.<\/p>\n

\"POES<\/a>

POES AVHRR Cloud Top Height product<\/p><\/div>\n

All of the above satellite evidence suggests that the gravity waves seen on the water vapor imagery were not surface-based, but were located at a higher altitude within the middle troposphere. In fact, the GOES-13 water vapor weighting functions<\/a><\/strong> calculated using rawinsonde data from Lake Charles, Louisiana (upstream of the MCS)<\/em> and Tampa, Florida (downstream of the MCS)<\/em> both peaked around 450 hPa (below)<\/em><\/strong>, which tells us that the thermal energy being sampled by the water vapor channel in non-cloudy air was originating from within a high-altitude layer.<\/p>\n

\"Lake<\/a>

Lake Charles, Louisiana water vapor weighting function plot<\/p><\/div>\n

\"Tampa,<\/a>

Tampa, Florida water vapor weigting function plot<\/p><\/div>\n

CIMSS participation in GOES-R Proving Ground<\/strong><\/a> activities includes making a variety of\u00c2\u00a0 MODIS<\/strong><\/a> and POES AVHRR<\/strong><\/a> images and products available for National Weather Service offices to add to their local AWIPS workstations.<\/p>\n","protected":false},"excerpt":{"rendered":"

McIDAS images of 4-km resolution GOES-13 6.5 \u00c2\u00b5m water vapor channel data (above; click image to play animation) showed a well-defined warm\/dry “arc” feature (denoted by the brighter yellow color enhancement) just upwind of a large Mesoscale Convective System (MCS) that was moving eastward along the northern Gulf of Mexico and the adjacent Gulf Coast […]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[22,21,11,34,12,26,3],"tags":[],"class_list":["post-7745","post","type-post","status-publish","format-standard","hentry","category-avhrr","category-aviation","category-goes-13","category-goes-r","category-modis","category-poes","category-severe-convection"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/7745","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=7745"}],"version-history":[{"count":17,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/7745\/revisions"}],"predecessor-version":[{"id":7747,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/7745\/revisions\/7747"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=7745"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=7745"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=7745"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}