{"id":29013,"date":"2018-07-19T23:55:56","date_gmt":"2018-07-19T23:55:56","guid":{"rendered":"http:\/\/cimss.ssec.wisc.edu\/satellite-blog\/?p=29013"},"modified":"2018-08-11T15:43:49","modified_gmt":"2018-08-11T15:43:49","slug":"tornado-outbreak-in-iowa","status":"publish","type":"post","link":"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/archives\/29013","title":{"rendered":"Tornado outbreak in Iowa"},"content":{"rendered":"

\"GOES-16<\/a>

GOES-16 Upper-level Water Vapor (6.2 \u00b5m, top left),<\/em> Mid-level Water Vapor (6.9 \u00b5m, top right),<\/em> Low-level Water Vapor (7.3 \u00b5m, bottom left)<\/em> and “Red” Visible (0.64 \u00b5m, bottom right)<\/em> images [click to play MP4 animation]<\/p><\/div>GOES-16 (GOES-East)<\/em> Upper-level Water Vapor (6.2 \u00b5m<\/strong><\/a>), Mid-level Water Vapor (6.9 \u00b5m<\/strong><\/a>), Low-level Water Vapor (7.3 \u00b5m<\/strong><\/a>) and “Red” Visible (0.64 \u00b5m<\/strong><\/a>) images (above)<\/strong><\/em> revealed the well-defined signature of a mid-tropospheric lobe of vorticity moving from southeastern South Dakota across Iowa during the day on 19 July 2018<\/strong><\/a> — this feature provided synoptic-scale forcing for ascent which aided in the development of severe thunderstorms in central and eastern Iowa. A number of tornadoes were reported, along with some large hail and damaging winds (SPC storm reports<\/strong><\/a>).<\/p>\n

\"GOES-16<\/a>

GOES-16 “Red” Visible (0.64 \u00b5m)<\/em> images, with SPC storm reports plotted in red [click to play MP4 animation]<\/p><\/div>A closer look using 1-minute Mesoscale Domain Sector<\/strong><\/a> GOES-16 “Red” Visible (0.64 \u00b5m) images (above)<\/strong><\/em> showed the line of thunderstorms as they developed in advance of an approaching cold\/occluded front (surface analyses<\/strong><\/a>). Two larger storms were dominant, which produced tornadoes causing significant damage and injuries in Pella KPEA<\/strong><\/a> and Marshalltown KMIW<\/strong><\/a> — above-anvil cirrus plumes<\/a><\/strong> were evident with both of these supercells. In addition, early in the animation a few orphan anvils could be seen along the southern end of the line (southeast and east of Des Moines KDSM).<\/p>\n

The corresponding GOES-16 “Clean” Infrared Window (10.3 \u00b5m<\/strong><\/a>) images (below)<\/strong><\/em> showed cloud-top infrared brightness temperatures of -65\u00baC to -70\u00baC with the larger Pella storm<\/strong><\/a>, and around -55\u00baC with the smaller Marshalltown storm<\/strong><\/a> to the north.<\/p>\n

\"GOES-16<\/a>

GOES-16 “Clean” Infrared Window (10.3 \u00b5m)<\/em> images, with SPC storm reports plotted in red [click to play MP4 animation]<\/p><\/div>

\"GOES-16<\/a>

GOES-16 “Clean” Infrared Window (10.3 \u00b5m) image, with ProbSevere contour and parameters [click to enlarge]<\/p><\/div>The NOAA\/CIMSS ProbSevere<\/strong><\/a> model (viewed using RealEarth<\/strong><\/a>) had a ProbTor value of 74% at 2055 UTC for the Pella storm (above)<\/em><\/strong> and 83% at 2130 UTC for the Marshalltown storm (below)<\/strong><\/em>. GOES-derived Cloud-top glaciation rate<\/strong> (from infrared imagery) is one of the predictors used in the model.<\/p>\n

\"GOES-16<\/a>

GOES-16 “Clean” Infrared Window (10.3 \u00b5m)<\/em> image, with ProbSevere contour and parameters [click to enlarge]<\/p><\/div>ProbSevere time series plots for the Pella and Marshalltown cells are shown below. They indicated that the Pella storm was long-lived, persisting past 0300 UTC — and that ProbTor ramped up quickly and then down quickly, bracketing the time of the tornado in Marshalltown.<\/p>\n

\"NOAA\/CIMSS<\/a>

NOAA\/CIMSS ProbHail (Green), ProbWind (Blue) and ProbTor (Red) for the cell that produced the Pella IA tornado [click to enlarge]<\/p><\/div>

\"\"<\/a>

NOAA\/CIMSS ProbHail (Green), ProbWind (Blue) and ProbTor (Red) for the cell that produced the Marshalltown IA tornado [click to enlarge]<\/p><\/div>A toggle between 375-meter resolution Suomi NPP VIIRS Visible (0.64 \u00b5m) and Infrared Window (11.45 \u00b5m) images at 1946 UTC (below)<\/strong><\/em> provided a look at the early stage of\u00a0development of tornado-producing convection.<\/p>\n

\"Suomi<\/a>

Suomi NPP VIIRS Visible (0.64 \u00b5m)<\/em> and Infrared Window (11.45 \u00b5m)<\/em> images, with plots of SPC tornado reports within +\/- 30 minutes of the images [click to enlarge]<\/p><\/div>Additional satellite imagery and analysis of this event can be found on the Satellite Liaison Blog<\/a><\/strong>.<\/p>\n

<\/p>\n
\n

The EF-3 damage at the Vermeer Plant in Pella. Preliminary estimated peak winds of 144 mph and a max tornado width of 400 yards. Tornado end time and path length still TBD. #iawx<\/a> pic.twitter.com\/aMMmhdn21N<\/a><\/p>\n

\u2014 NWS Des Moines (@NWSDesMoines) July 21, 2018<\/a><\/p><\/blockquote>\n