|Numerical Forecasts||Satellite||Surface Obs||Forecasts|
About Satellite Imagery
America is well served by two operational geostationary satellites and a brand-new satellite that is currently being checked out. These go by the acronym “GOES” and are located above the equator to provide coverage over the western and eastern parts of the continent. The satellites look at the whole globe, so that scenes over the Continental U.S. are distorted by the curvature of our planet, but many websites that show the images rectify them so that they appear to be seen from directly above. One of the best sites is found at the College of Dupage, which serves up a collection of high-resolution images dedicated to storm chasers.
|Sources of satellite imagery|
|College of DuPage||Zoomed-in images and animations of selected sectors across the United States. Choose from tabs on the left side.|
|NOAA Geostationary Satellite Server||Omnibus site for satellite coverage over the continental USA. Images and animations available.|
|GOES 16 images and animations at RAMMB||This latest GOES satellite has spectacular capabilities but is still undergoing initial testing. Loading may be slow.|
Types of Images
Images from the satellite are taken in both visible and infrared wavelengths. Visible images are only useful during daylight hours; infrared images are used throughout the day. Infrared scenes have a lower resolution than those made a visible frequencies. Most television stations will only show you the infrared images in their weather broadcasts.
Having said all that, the latest geostationary satellite, GOES 16, is re-writing some of the old rules. Number 16 has a very much improved capability, including the ability to acquire visible-light images at night, more visible and infrared bands, and higher resolution. Many of its capabilities are still being discovered, and it will no doubt be one of the main satellite resources even though it does not become fully operational until after the eclipse. You can check it out at the link above.
If the eclipse comes to your site in the early morning , you will have to use night infrared images to watch the clouds in the hours before. Because infrared wavelengths are emitted from surfaces on the Earth according to their temperature, features can “blend” together if they have similar temperatures. In particular, low cloud can be difficult to distinguish from the surface overnight as the ground cools and the distinction between cloud and surface diminishes. High-level clouds with their relatively cold temperatures are normally easy to distinguish from lower layers in the summer months.
Animation of the images help to distinguish cloud from ground but even then the distinction is not always clear. Falling temperatures overnight or rising temperatures at daybreak can mimic cloud motions.