Doppler Radar
NWS Radar on the Web
The National Weather Service has presents Doppler radar images on the web in two manners; a Standard version (an all-in-one image) and an Enhanced version by individual interactive layers. Follow are the differences and strengths/weakness of each.
Standard Version | Enhanced Version |
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In the Standard version, each radar image is combined with a legend, highways, and county/state outline overlays into one graphic which is made available via the web. | In the Enhanced version, individual radar images are transmitted as well as individual overlay maps for highways, rivers, cities, county boundaries and severe weather warnings. |
Advantages:
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Advantages:
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How can you quickly tell which version of the radar you are viewing? The two obvious differences are in the border color around the radar image and background image. The standard version have a light blue border with a white background. The Enhanced version will have a dark blue border with a map background showing topography. (Samples below)
Standard Version | Enhanced Version |
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In addition, below every radar image, standard or enhanced, are thumbnail images of different sectors of the nation. These thumbnails contain live radar information providing, at a glance, a quick overview of where precipitation is occurring from the base reflectivity data.
National Radar Mosaic Sectors |
Alaska![]() |
Pac. NW![]() |
N. Rockies![]() |
Upr. Miss.![]() |
Grt. Lakes![]() |
Northeast![]() |
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Clicking any of these images provides a high resolution sector image. Another click takes you to individual radar images.
These sector views are also divided into standard and enhanced. However, all sector images are non-interactive. The delineation of standard and enhanced allows you to know which version of individual radar you can obtain from each sector.
![The 'oval' 124 nm range ring The 'oval' 124 nm range ring](images/fws_projection.jpg)
Radar Map Projections
Except for the state of Alaska, the radar images provided by the National Weather Service are in an unprojected latitude/longitude format. This allows geographic information system (GIS) software to ingest NWS radar data for display with other information such as population density, etc.
Because of this unprojected format, the radar images appear "squashed" or oval shaped. The squashing of the radar image increases with increasing distance north (and south) of the equator. The oval ring in the image (right) is the 124 nautical mile range ring, which is the distance "seen" in a "short range" Doppler radar image.