Regional And Mesoscale Meteorology Team
Daily Satellite Discussion
Sunday October 26,1997
Figure 1 shows the GOES-9 visible image from Sunday October 26, 1997 at 2030 UTC. One can see that a large region of the central plains from Colorado, Nebraska, Kansas, Oklahoma, and regions eastward all appear white. This region is divided into snow covered ground, liquid water cloud over snow, and liquid water cloud over bare ground. By only looking at this visible imagery one cannot distinguish the snow covered ground from the low-level liquid water clouds.
Figure 2 shows the reflectivity product at the same time as Figure 1. Note how dark the region is over eastern Colorado, southeast Wyoming, Nebraska, and Kansas. This is the snow covered ground and shows up dark since snow is poorly reflective at 3.9 micrometers.
A bright, highly reflective, north-south region over east central Nebraska is low-level liquid water clouds over snow. Over Oklahoma, the bright region is also low-level liquid water clouds over bare ground.
Also note the dark band extending from northern Missouri over southeast and eastern Iowa into Wisconsin. This band is upper level clouds composed of, poorly reflective, ice water. Also one can see that this band was surrounded by reflective liquid water clouds.
One should look at these two images carefully to see how well one can distinguish between snow, liquid water clouds, and ice water clouds.
Louie Grasso