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INTERPRETING WEATHER IMAGES
Meteorologists spend years learning how to interpret cloud photos. Our goal here is for the students to learn some very basic skills. For this section, please refer to the sample images provided. It will also be helpful for you to begin viewing some current images on the web.

Know your Geography - The first thing to do with a weather image is to determine what geographical region is shown. For example, the cloud image for "Eastern North America" shows most of the US, Mexico and Canada, the Caribbean and some of the Atlantic Ocean. It is in black and white, but they've added lines to show the state and national borders. Geography is important for three reasons: 1) to know where you are looking; 2) to identify physical features that impact on cloud patterns; 3)to recognize different weather conditions in different latitudes.

Clouds are white - This may seem obvious, but it is the key to identifying clouds in these images.

Scale is very important - Students can easily be confused by the scale in these images. A big cloud seen from your school will be just the tiniest speck seen from space. In the sample cloud image for "Eastern North America," the clouds off the eastern coast are about three hundred miles across. The smallest object visible in GOES 8 images (such as these) is approximately 1 km by 1 km.

Focus on patterns - Students should not focus initially on naming clouds, but  rather on the patterns and shapes which identify where it is mostly cloudy and where it is mostly clear. They should look for large areas covered by a solid mass of clouds (probably a storm system) and areas covered by tiny white spots (probably fair-weather cumulus clouds). With practice, they will learn to recognize such shapes as the large curving "comma" of a storm system, or the band of clouds which typically circle the Earth at the equator.

Watch the changing patterns -- One of the most powerful ways to look at cloud images is to see how the change over the course of a few hours or days. By downloading a new regional image every hour, students can track the motion of a hurricane moving up the Eastern seaboard. Or, they can follow a storm systems's motion from the West coast to the East coast over a few days. They can see thunderstorms build up in the afternoon in the Southern United States. The central idea is for students to get a sense of the dynamics of clouds.

Teachers' Guide Page 8.11