Fog & Low Clouds, GeoColor

Example of a GeoColor Fog and Stratus RGB


A robust, all-purpose product for general forecasters produced during both day and nighttime. The product is particularly useful for detecting low clouds and potential fog during nighttime. During the day, the clouds are superimposed on NASA’s Blue Marble image derived from the MODIS imager, and at night, clouds are superimposed on either a DMSP OLS or VIIRS Day Night Band background that shows city lights. Note that while the GeoColor product is not a standard RGB, it is largely constructed using RGB methods.

Coverage: Day and nighttime


  • Daytime: 0.6 µm Vis (on NASA’s Blue Marble background or similar true color background image)
  • Nighttime: GOES 3.9 µm IR and 10.8 µm IR (on top of a DMSP OLS background image showing city lights)

Color scheme:

  • All clouds from the visible channel are white during daytime
  • At night from infrared data, water clouds including low clouds and potential fog are pink and high clouds are white


  • Intuitive and easy to interpret
  • Can be produced 24 hours a day
  • Can discriminate ice from water clouds (including low clouds and potential fog) during nighttime, and shows all cloud types as white during daytime


  • Brief gaps in cloud detection near sunrise and sunset as the product transitions between infrared (nighttime) and visible (daytime).
  • Because only visible channel information is used during daytime, product can not distinguish between water and ice cloud types.

Live data links:

Additional information:


2 images, one GOES IR from 31 Mar 2010 1215 UTC and a corresponding GeoColor Low Cloud over a DMSP OLS image

On the left is a nighttime GOES infrared image over Texas. As you can see, no low clouds or fog are evident. But they appear in orange in the low cloud product on the right. The yellow city lights are from the DMSP OLS background image.


GOES-East VIS/IR (Day/Night) animation, 29 Mar 2010 from 0712 to 1345 UTC

In this infrared loop, the white clouds are associated with a frontal system over the eastern seaboard, and the states of Michigan, Ohio, Kentucky, Tennessee, Alabama, and Georgia are almost cloud free. When the sun rises and the GeoColor product switches to visible data, low clouds appear over these states.

GOES-East VIS/IR (Day/Night) animation, 29 Mar 2010 from 0712 to 1345 UTC

This animation of the GeoColor product shows the evolution of low and high clouds. Nighttime water clouds are evident in pink. Notice how they turn white when the sequence transitions to daytime.