These images are generated by geostationary satellites orbiting 22,000 miles above the equator looking at the United States. These include visible, infrared and water vapor images. The images are updated once an hour at about 30 after the hour.
Satellite and Radar
Sample composite radar summary
The composite radar summary is a plot of most of the available information broadcast as part of the RCM radar data.
The first plot is the actual radar summary. The radar summary displays areas where precipitation is falling. The intensity is based on color where:
light rain or snow
light thunderstorms/moderate rain showers
potential flooding rains/strong thunderstorms
flooding rains/potential severe thunderstorm
Radar sites that don't report precipitation can report either:
NE - No echos/precipitation within the radar range. NA - Radar data not available. OM - Radar inoperative due to maintenance.
The next type of data is the individual storm movement which is plotted as a wind barb (See Weather Symbol Legend). This indicates how fast and in what direction the individual storms are moving.
The next type of data is the precipitation tops which are plotted over the top as a number in 100s of feet. This is the maximum altitude of the precipitation as seen by the radar. This can range from 10,000 feet in snow showers to 20,000 with rain showers to 40,000 feet with thunderstorms. Severe thunderstorm tops can reach 50,000 to 70,000 feet.
Severe weather watch boxes
The last type of data are the severe weather watch boxes. The area covered by the watch is enclosed by a white box. The watch number and type as well as the expiration time are also listed.
Specifies a tornado watch #335 which expires at 5Z
Specifies a severe thunderstorm watch #336 which expires at 8Z