{"id":8913,"date":"2011-09-27T21:38:23","date_gmt":"2011-09-27T21:38:23","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=8913"},"modified":"2011-09-28T03:26:52","modified_gmt":"2011-09-28T03:26:52","slug":"persistent-cut-off-low-over-the-north-central-us","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/8913","title":{"rendered":"Persistent cut-off low over the north-central US"},"content":{"rendered":"
\"GOES-15<\/a>

GOES-15 6.5 \u00c2\u00b5m water vapor images (click image to play animation)<\/p><\/div>\n

McIDAS images of GOES-15 6.5 \u00c2\u00b5m water vapor channel data (above; click image to play animation)<\/strong><\/em> showed the changing signature of a persistent upper level cut-off low lingering over the north-central US during the 23 September<\/strong><\/a> – 27 September 2011<\/strong> period. As the system lingered over the region, it produced widespread wind gusts in the 30-40 mph range (with a peak wind gust of 46 mph at Green Bay, Wisconsin),<\/em> and rainfall totals of 4-5 inches at some locations in northern Illinois.<\/p>\n

AWIPS images of the hourly GOES sounder Total Column Ozone product on 25 September <\/strong><\/a>– 26 September<\/strong><\/a> (below; click image to play animation)<\/strong><\/em> revealed a distinct elevated ozone signature (300-400 Dobson Units, green to red color enhancement),<\/em> which indicated that the height of the tropopause was lower in the vicinity of the cut-off low.<\/p>\n

 <\/p>\n

\"GOES<\/a>

GOES sounder Total Column Ozone product (click image to play animation)<\/p><\/div>\n

One notable impact associated with this cut-off low included thunderstorms along the Lake Michigan shoreline that produced a number of waterspouts that were seen from Milwaukee<\/strong><\/a> to Chicago<\/strong><\/a>. A comparison of MODIS 0.65 \u00c2\u00b5m visible channel and 11.0 \u00c2\u00b5m IR window channel image at 17:28 UTC (12:28 pm local time)<\/em> on 24 September<\/strong><\/a> (below)<\/strong><\/em> showed one of the storms that exhibited cloud top IR brightness temperatures colder than -40\u00c2\u00baC (blue color enhancement<\/em>), along with a number of cloud to ground lightning strikes as it moved inland.<\/p>\n

\"MODIS<\/a>

MODIS 0.65 \u00c2\u00b5m visible channel and 11.0 \u00c2\u00b5m IR window channel images<\/p><\/div>\n

Another impact of this cut-off low included a number of pilot reports of light to moderate turbulence over the central and southern Great Plains region. A well-defined bloom of cirrus clouds developed within a zone of high 400-200 hPa layer wind shear, as seen on 4-km resolution GOES-13 6.5 \u00c2\u00b5m water vapor channel images with overlays of CRAS<\/a><\/strong> model fields (below; click image to play animation)<\/strong><\/em>.<\/p>\n

\"GOES-13<\/a>

GOES-13 6.5 \u00c2\u00b5m water vapor images + turbulence reports + CRAS layer winds and shear (click image to play animation)<\/p><\/div>\n

Better detail of the banded structure of the cirrus cloud features within the high-shear deformation zone can be seen on a 1-km resolution MODIS 6.7 \u00c2\u00b5m water vapor image (below)<\/strong><\/em>. Note the pilot report of light to moderate turbulence during the entire flight from Denver (DEN) to Kansas City (MCI).<\/p>\n

\"MODIS<\/a>

MODIS 6.7 \u00c2\u00b5m water vapor image + pilot reports of turbulence<\/p><\/div>\n

A sequence of 1-km resolution MODIS 6.7 \u00c2\u00b5m water vapor channel images on 26 September<\/strong><\/a> (below)<\/strong><\/em> showed some very intricate dry air and moisture structures within the cut-off low during that particular day.<\/p>\n

\"MODIS<\/a>

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

In a comparison of MODIS 0.65 \u00c2\u00b5m visible channel and MODIS 6.7 \u00c2\u00b5m water vapor channel images (below),<\/strong><\/em> note how much more structure is seen in the water vapor image — even in areas that are cloud-free in the visible image. This allows a number of water vapor features and gradients to be tracked using 3 consecutive GOES water vapor images, to produce MADIS<\/a><\/strong> high-altitude atmospheric motion vectors (AMVs) that can provide important wind direction and wind speed data. An AMV with a wind speed of 130 knots (at 300 hPa) was seen in the dry slot over southern Missouri.<\/p>\n

\"MODIS<\/a>

MODIS 0.65 \u00c2\u00b5m visible image + MODIS 6.7 \u00c2\u00b5m water vapor image + MADIS satellite winds<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

McIDAS images of GOES-15 6.5 \u00c2\u00b5m water vapor channel data (above; click image to play animation) showed the changing signature of a persistent upper level cut-off low lingering over the north-central US during the 23 September – 27 September 2011 period. As the system lingered over the region, it produced widespread wind gusts in the […]<\/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":[21,15,11,43,30,12,25],"tags":[],"class_list":["post-8913","post","type-post","status-publish","format-standard","hentry","category-aviation","category-goes-sounder","category-goes-13","category-goes-15","category-lightning","category-modis","category-satellite-winds"],"acf":[],"_links":{"self":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/8913","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=8913"}],"version-history":[{"count":12,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/8913\/revisions"}],"predecessor-version":[{"id":8915,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/posts\/8913\/revisions\/8915"}],"wp:attachment":[{"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/media?parent=8913"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/categories?post=8913"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-json\/wp\/v2\/tags?post=8913"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}