The Goddard Space Flight Center in Maryland posts new GOES weather satellite images up on the web about every half hour. I have found their images to be the best source of high quality weather satellite pictures. They have monochrome images in standard TIFF format that are about 1 MB in size. Many views are available including the whole globe or subsets of particular regions such as the Great Lakes. The GOES imagery will generally appear dark on your computer monitor and can be greatly improved by doing a simple histogram stretch in an image processing software program.

Although the GOES images are monochrome they can be easily be colorized using a software program like Adobe Photoshop to apply tints to the image. Colorized images are easier to view because the color contrast helps to differentiate areas of snow cover, lake ice, and clouds.

STEP 1: First download the GOES image you are interested in working with. Also download the MAP.TIF or MAP.GIF file located at the bottom of the GOES directory. The MAP file will be used to make a mask. Using Adobe Photoshop retouch the MAP file so areas of water are white and land is black. Save this file as MASK.TIF

Sample Image Mask created by retouching the GOES MAP file

STEP 2: Open the GOES satellite image. From the menu bar select IMAGE:ADJUST:LEVELS and increase the brightness and contrast of the picture by moving the black point and white point sliders. Then convert the image into RGB color space by selecting IMAGE:MODE:RGB from the menu bar.

Use the CHANNELS palette to create a new alpha channel and copy MASK.TIF into the alpha channel.

Make the alpha channel mask the active selection.

STEP 3: You should see the "marching ant" outlining the areas of water in your image. Now go to IMAGE:ADJUST:CURVES. Create anchor locking points for the midtone and highlight areas. This is done so the clouds in the image do not pick up a color tint. Now pull down from RGB to BLUE in the Channel section at the top of the dialog box. Slide the bottom of the curve up. You should see the water in your image turn blue. Hit the OK button.

STEP 4: Choose the inverse selection. Now the "marching ants will be surrounding the land areas of the image. Go back to IMAGE:ADJUST:CURVES. Again create anchor locking points for the midtone and highlight areas. Now pull down from RGB to RED at the top of the dialog box. Slide the bottom of the curve up. You should see the land in your image turn red. Hit the OK button. Use the SELECT:COLOR RANGE function to select the land area. Then use the HUE slider to adjust the land color to something that looks natural. You might want to do this step twice to select brown tones for desert areas and green tones for other areas.

STEP 5: The last step is to sharpen the picture. Select FILTER:SHARPEN:UNSHARP MASK. Try values of Amount=200%, Radius =0.5, and Threshold=7.