{"id":16233,"date":"2014-07-24T22:07:05","date_gmt":"2014-07-24T22:07:05","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=16233"},"modified":"2014-07-30T00:16:26","modified_gmt":"2014-07-30T00:16:26","slug":"severe-thunderstom-strikes-virginia-campground","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/16233","title":{"rendered":"Severe thunderstorm strikes Virginia campground"},"content":{"rendered":"
\"GOES-13<\/a>

GOES-13 10.7 \u00b5m IR channel images (click to play animation)<\/p><\/div>\n

A supercell thunderstorm intensified as it moved eastward across the Chesapeake Bay (just ahead of an approaching surface cold front<\/strong><\/a>) on the morning of 24 July 2014<\/strong><\/a> — as it reached the Virginia shore of the Delmarva Peninsula, it produced an EF-1 tornado and damaging straight line winds that were responsible for 2 fatalities and 36 injuries at the Cherrystone Family Camping Resort (located at the *<\/strong> symbol on the images). The storm also produced golf ball to baseball size hail (NWS damage survey<\/strong><\/a> | SPC storm reports<\/strong><\/a>). McIDAS images of GOES-13 10.7 \u00b5m IR channel data (above; click image to play animation; also available as an MP4 movie file<\/a>)<\/strong><\/em> showed that the cloud-top IR brightness temperatures associated with the storm cooled quickly, from -45\u00ba C at 11:15 UTC to -64\u00ba C at 12:30 UTC. The temperature value was close to that of the tropopause (at a height of 15.4 km)<\/em> on the 12 UTC rawinsonde data<\/strong><\/a> from Wallops Island, Virginia.<\/p>\n

The corresponding GOES-13 0.63 \u00b5m visible channel images (below; click image to play animation; also available as an MP4 movie file<\/a>)<\/strong><\/em> revealed the presence of an overshooting top at 12:30 UTC<\/strong><\/a>\u00a0 (the time that the IR cloud-top brightness temperature values reached their minimum), which was also flagged by the automated Overshooting Tops<\/strong><\/a> detection algorithm.<\/p>\n

\"GOES-13<\/a>

GOES-13 0.63 \u00b5m visible channel images (click to play animation)<\/p><\/div>\n

AWIPS-II images of the NOAA\/CIMSS ProbSevere<\/strong><\/a> product (below)<\/strong><\/em> followed the radar feature associated with the supercell thunderstorm. Around 11:30 UTC, the ProbSevere value was low, around 5-10%, a result of weak satellite-detected growth (and moderate glaciation) early in the storm’s life, along with low values of MRMS<\/strong><\/a> Maximum Expected Size of Hail (MESH). Environmental parameters from the Rapid Refresh model that were supportive of convection: MUCAPE exceeded 2200 J Kg and Shear values were greater than 30 m\/s. As the cell tracked to the east and began to move over Chesapeake Bay, both MUCAPE and Shear gradually increased, to values near 2400 J\/kg and 35 m\/s, respectively. MRMS MESH was oscillating as the cell approached Chesapeake Bay, from 0.44 inches at 11:42 UTC (ProbSevere value of 10%) to 0.37 inches at 11:46 UTC (ProbSevere of 7%) to 0.65 inches at 11:48 UTC (ProbSevere of 29%) to 0.56 inches at 12:00 UTC (ProbSevere of 18%). As the storm moved over the Bay, MESH sizes jumped, to 0.86″ at 12:04 UTC (ProbSevere of 58%, the first crossing of the 50% threshold), to 1.02″ at 12:06 UTC (ProbSevere of 71%), to 1.86″ at 12:12 UTC (ProbSevere of 92% , the first crossing of the 90% threshold), and to 3.09″ (!) at 12:16 UTC (ProbSevere of 91%). At 12:20 UTC, when the Tornado Warning was issued, MRMS MESH was 3.51″ and ProbSevere remained at 91%. Thus, the warning was issued 16 minutes after ProbSevere exceeded 50%, and 8 minutes after ProbSevere was greater than 90%. The NWS storm survey indicated that the campsite fatalities occurred around 12:33 UTC, or 13 minutes after the issuance of the tornado warning.<\/p>\n

\"NOAA\/CIMSS<\/a>

NOAA\/CIMSS ProbSevere product<\/p><\/div>\n

The rapid intensification of the system as it moved over the Chesapeake begs the question: was instability diagnosed? In the animation below, GOES-13 sounder Derived Product Images (DPI) of Lifted Index (top panel) and CAPE (bottom panel) showed a rich source of instability just south of the cloud-obscuring convection (and ahead of the southward-moving cold front). Lifted Index values derived at 1147 UTC<\/a> were around -6 at the mouth of the Chesapeake Bay (bright yellow enhancement); CAPE values were around 2500 J\/kg (yellow and red enhancements).<\/p>\n

\"GOES-13<\/a>

GOES-13 Sounder DPI estimates of Lifted Index (top) and CAPE (bottom) [click to play animation]<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

A supercell thunderstorm intensified as it moved eastward across the Chesapeake Bay (just ahead of an approaching surface cold front) on the morning of 24 July 2014 — as it reached the Virginia shore of the Delmarva Peninsula, it produced an EF-1 tornado and damaging straight line winds that were responsible for 2 fatalities and […]<\/p>\n","protected":false},"author":18,"featured_media":16234,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[44,15,11,60,3],"tags":[],"class_list":["post-16233","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-awips-ii","category-goes-sounder","category-goes-13","category-probsevere-severe-convection","category-severe-convection"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/16233","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=16233"}],"version-history":[{"count":48,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/16233\/revisions"}],"predecessor-version":[{"id":16304,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/16233\/revisions\/16304"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media\/16234"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=16233"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=16233"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=16233"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}