Microburst hits Dallas Cowboys football practice facility
GOES-12 10.7 µm IR images
AWIPS images of the GOES-12 10.7 µm “IR window” channel (above) showed the development of severe thunderstorms that moved across the Dallas/Fort Worth metro area in northeast Texas on 02 May 2009. Cloud top temperatures quickly cooled into the -70º to -80ºC range (black to light gray color enhancement) as the storms began to produce hail (up to 1.75 inch in diameter), strong surface winds, and a few tornadoes (SPC storm reports). At around 20:30 UTC (3:30 pm local time), strong winds from a microburst caused the collapse of a canopy covering a practice field at the Dallas Cowboys football facility at Valley Ranch (located just to the northeast of Dallas/Fort Worth International Airport, KDFW), with several injuries being reported.
A closer view using a 1-km resolution MODIS 11.0 µm IR window image (below) showed greater detail in the cloud top temperature structure, with some pixels as cold as -84ºC (violet color enhancement). Note the sharp “upshear” (western) edge of the storm’s anvil; in addition, there was a subtle “warm trench” signature surrounding the cold cluster of overshooting tops that was located to the southwest of KDFW — this IR storm top signature is sometimes seen with severe thunderstorms.
MODIS 11.0 µm IR image
A comparison of the 4-km resolution GOES-12 10.7 µm IR image with the corresponding 1-km resolution MODIS 11.0 µm IR window image (below) demonstrated the advantage of higher spatial resolution for use in the detection of severe storm cloud top signatures. The coldest GOES-12 cloud top temperatures were -77ºC, about 7ºC warmer than the -84ºC seen on the MODIS image.
GOES-12 10.7 µm IR + MODIS 11.0 µm IR images
According to the 00:00 UTC rawinsonde report from Dallas/Fort Worth (below), these cold cloud top temperatures associated with the intense overshooting tops were several degree colder than the sounding tropopause temperature of -74ºC.
Dallas/Fort Worth TX rawinsonde report