Technical Requirements:

• Adobe Flash Player 9.0+ plug-in
• Windows 2000+ with latest updates installed
• Mac OS X 10.3+
• Firefox 1.1+, Internet Explorer 6.0+ or Safari 2.0+
• Works best with a broadband connection

Navigating the Map:

• Use the magnifying glass tools at upper left to zoom in or out, or use the scroll button on your mouse if you have one.
• Click on the map and drag your mouse to view different areas.
• The date and time of the image is displayed at the top right.

Map Buttons:

• National View displays the continental United States. Click the map to zoom in on a particular area.
• Local View shows an area within about 100 miles of our broadcast site.
• Spotlight takes you right to a featured location—for example, a site where the weather is especially newsworthy.

Map Choices:
Toggle between satellite and map view—both views show state borders and cities. Satellite view lets you see the area's topography, with mountain ranges and other formations labeled. Map view resembles a road map.

Surface Images:
Our maps are created with stored imagery, not a current picture of the terrain. Snow in the radar doesn't mean you'll see snow when you zoom in on the earth's surface, nor will the terrain go dark if you view it at night.

Radar and Clouds:
Checkboxes allow you to overlay either view with Radar and/or Clouds. When Clouds is selected, use the Transparency slider to make the cloud cover easier (or more difficult) to see through. Sliding to 0% makes the clouds opaque, while 100% makes them seem to disappear. Note that sometimes, radar can indicate light rain when no precipitation is reaching the ground. This is called virga — rain evaporating before it reaches the ground — and can happen any time of year.

Animate Your Map:
The Loop button starts a repetitive animation that shows the movement of clouds and radar over a period of time. The date and time at upper right changes with the animation. When the animation is running, the button is labeled Stop. Click it to stop the animation and go back to the current image.

Lightning:
Each lightning icon represents one or more lightning strikes in the area — up to hundreds. The number represented depends on your zoom level. Lightning reports are from 0 to 15 minutes before the time stamp.