SATELLITE  INTERPRETATION  DISCUSSION

 NOAA NESDIS
 Regional and Mesoscale 
Meteorology Team
Cooperative Institute for Research in the Atmosphere (CIRA)
Colorado State University
Fort Collins, Colorado

November 2, 1998

The subject of today's satellite interpretation discussion is the appearance of thunderstorm overshooting tops  in satellite imagery.  The example we are using is from a thunderstorm event in South Dakota earlier this year, which produced the fatal multiple vortex F4 tornado at Spencer, SD.  In many instances the 10.7 IR satellite brightness temperature minimum is coincident with the overshooting tops of thunderstorms. In other cases, the overshoot and the brightness temperature minimum do not coincide. Figure 1 shows the thunderstorm in the 10.7 IR channel at 0125 UTC. Brightness temperature minimum appears as the lighter blue colors. Figure 2 is the visible image of the thunderstorm also at 0125 UTC. Two distinct overshooting tops can be seen near the southwest section of the storm complex. The contour plot of the 10.7 µm IR brightness temperature (Figure 3) can be compared to the overshooting tops in the visible image to identify the location brightness minimum.  The area of the brightness temperature minima (210 contour) is between the two overshooting tops previously pointed out in the visible image. Click on images below for full display.