![\"GOES-16](\"https:\/\/cimss.ssec.wisc.edu\/satellite-blog\/wp-content\/uploads\/sites\/5\/2019\/03\/190303_goes16_visible_spcStormReports_AL_GA_anim.gif\")
<\/a>GOES-16 “Red” Visible (0.64 \u00b5m)<\/em> images, with SPC storm reports plotted in red [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>An outbreak of severe thunderstorms occurred during the afternoon hours of 03 March 2019<\/strong><\/a>, which produced large hail, damaging winds and tornadoes (SPC storm reports<\/strong><\/a>). 1-minute Mesoscale Domain Sector<\/strong><\/a> GOES-16 (GOES-East)<\/em> “Red” Visible (0.64 \u00b5m<\/strong><\/a>) images (above)<\/strong><\/em> showed the development of numerous thunderstorms along and ahead of an advancing cold front (surface analyses<\/strong><\/a>); many of those storms exhibited well-defined overshooting tops. Tornado track summaries for Alabama and Georgia are available from NWS Birmingham<\/strong><\/a> and NWS Atlanta<\/strong><\/a>.<\/p>\n The corresponding GOES-16 “Clean” Infrared Window (10.3 \u00b5m<\/strong><\/a>) images are shown below. Cloud-top infrared brightness temperatures cooled to around -70\u00baC (darker black enhancement)<\/em> with many of the stronger storms — judging from rawinsonde data from Birmingham, Alabama (at 12 UTC<\/strong><\/a>) and Peachtree City, Georgia (at 18 UTC<\/strong><\/a>), this roughly corresponded to an air parcel rising significantly past the tropopause to an altitude of at least 15 km.<\/p>\n GOES-16 “Clean” Infrared Window (10.3 \u00b5m)<\/em> images, with SPC storm reports plotted in cyan [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>An area which included western Lee County (located in far eastern Alabama, adjacent to the Georgia border) was highlighted by a SPC MCD<\/strong><\/a> that was issued at 1900 UTC. Beginning about an hour later, 2 large tornadoes producing EF2 to EF4 damage moved across southern Lee County — initially beginning around 2000 UTC<\/strong><\/a>, then again beginning around 2050 UTC<\/strong><\/a> — and the formation of prominent overshooting tops was evident in GOES-16 Visible and Infrared imagery (below)<\/strong><\/em>. Station identifier KAUO<\/strong><\/a> in Lee County is the Auburn-Opelika Airport. (side note: later, around 2204 UTC, the Weedon Field Airport KEUF<\/strong><\/a> METAR site to the south of Lee County was directly hit by a separate EF2 tornado<\/strong><\/a>, and rendered inoperative)<\/p>\n GOES-16 “Red” Visible (0.64 \u00b5m, left)<\/em> and “Clean” Infrared Window (10.3 \u00b5m, right)<\/em> images, with SPC storm reports plotted in red\/cyan — Lee County, Alabama is outlined in solid blue, with other affected counties in dashed blue [click to play animation | MP4<\/strong><\/a>]<\/p><\/div>In a plot of the GOES-16 “Clean” Infrared Window coldest<\/em> brightness temperature for the EF4-tornado storm’s overshooting top as it moved from Macon\/Lee Counties in Alabama to Muscogee\/Harris\/Talbot Counties in Georgia (below)<\/strong>,<\/em> 3 distinct periods of cooling\/warming occurred — with the warming indicative of a temporary collapse of the overshooting top pulse. The first (and largest-magnitude) cold\/warm pulse (-70.3\u00baC to -65.6\u00baC) occurred from 1953-1959 UTC — just prior to the beginning of the Beauregard-Smiths Station EF4 Tornado<\/strong><\/a> at 2000 UTC. A second cold\/warm pulse (-70.8\u00baC to -66.9\u00baC) occurred from 2006-2012 UTC, with a third (-70.0\u00baC to -66.0\u00baC) from 2015-2022 UTC. At 2029 UTC the long-track tornado then crossed into Muscogee County in Georgia<\/strong><\/a>, producing EF3 damage.<\/p>\n Plot of the coldest GOES-16 “Clean” Infrared Window (10.3 \u00b5m)<\/em> overshooting top brightness temperatures, 2040-2115 UTC [click to enlarge]<\/p><\/div>The NOAA\/CIMSS ProbSevere<\/strong><\/a> product (below)<\/em><\/strong> displayed a high tornado probability for the cells that approached Lee County, as discussed by the Hazardous Weather Testbed<\/strong><\/a>. The ProbSevere model incorporates GOES-derived Normalized vertical growth rate and Cloud-top glaciation rate as 2 of its predictors.<\/p>\n MRMS MergedReflectivity composite, with countours of the ProbSevere parameter [click for link to HWT blog post]<\/p><\/div>A comparison of Aqua MODIS Visible (0.65 \u00b5m) and Infrared Window (11.0 \u00b5m) images along with the Total Precipitable Water derived product at 1836 UTC (below)<\/strong><\/em> showed that a few large thunderstorms had begun to develop by that time; TPW values were as high as 43 mm (1.7 inches) over far southwestern Georgia.<\/p>\n Aqua MODIS Visible (0.65 \u00b5m),<\/em> Infrared Window (11.0 \u00b5m)<\/em> and Total Precipitable Water images at 1836 UTC [click to enlarge]<\/p><\/div> Suomi NPP VIIRS Day\/Night Band (0.7 \u00b5m) image, with plots of available NUCAPS soundings [click to enlarge]<\/p><\/div>An overpass of the Suomi NPP satellite around 1850 UTC provided NUCAPS<\/strong><\/a> soundings in non-cloudy areas (above)<\/strong><\/em>. One of the Good quality (green)<\/em> NUCAPS soundings in the pre-storm environment was located over southwestern Georgia (circled in magenta)<\/em> — it showed a Most Unstable CAPE value of 1264 J\/kg, with a Lifted Index value of -4 (below)<\/strong><\/em>.<\/p>\n NUCAPS sounding over southwestern Georgia [click to enlarge]<\/p><\/div>The GOES-16 All Sky CAPE<\/strong><\/a> product (below)<\/strong><\/em> showed a trend of destabilization across southern Alabama and southern Georgia during the 5 hours leading up to the fatal tornadoes in Lee County AL.<\/p>\n GOES-16 All Sky CAPE product [click to play animation]<\/p><\/div>\n ===== 05 March Update =====<\/strong><\/p>\n Comparison between Terra MODIS True Color and False Color RGB images on 24 February and 05 March 2019 [click to enlarge]<\/p><\/div>A toggle between before\/after (24 February \/ 05 March 2019) Terra MODIS True Color and False Color Red-Green-Blue (RGB) images from the MODIS Today<\/strong><\/a> site (above)<\/strong><\/em> showed subtle evidence of portions of a tornado damage path — presumably that of the EF4 tornado that began in\/near Lee County, Alabama and ended in far western Georgia. Click an additional time on the image to view at full magnification.<\/p>\n Sentinel-2 True Color images (below)<\/strong><\/em> provided a higher-resolution view of the tornado damage path. Imagery courtesy of Sentinel Hub<\/strong><\/a>.<\/p>\n Sentinel-2 True Color RGB images from 24 February and 06 March [click to enlarge]<\/p><\/div> The path of the #tornado<\/a> that hit #Alabama<\/a> last March 3 is clearly visible from images of #Sentinel2<\/a> ?. pic.twitter.com\/GLatHrIQ5r<\/a><\/p>\n \u2014 Annamaria Luongo (@annamaria_84) March 7, 2019<\/a><\/p><\/blockquote>\n<\/a><\/a><\/a><\/a><\/a><\/a><\/a><\/a><\/a><\/a>\n