WSR 88D - Weather Surveillance Radar 88 Doppler (the 88 refers to the year 1988 when the system was commissioned). Commonly called NEXRAD, which stands for the next generation of weather radar, is used to warn the people of the United States about dangerous weather and its location. Meteorologists can now warn the public to take shelter with more notice than any previous radar. There are 158 NEXRAD radar systems deployed throughout the United States and at selected overseas locations. The maximum range of the NEXRAD radar is 250 nautical miles. The NEXRAD network provides significant improvements in severe weather and flash flood warnings, air traffic safety, flow control for air traffic, resource protection at military bases, and management of water, agriculture, forest, and snow removal.

 

The Weather Surveillance Radar 88-D at Jackson, Kentucky. The building below the dome houses the necessary computer processors which control operation of the radar data. The tower is 82 feet, plus 32 feet to the top of the dome.

 

The WSR-88D shows the location, intensity, and movement of precipitation, ranging from light snow flurries to very heavy rain and large hail. From movement of precipitation, the WSR-88D also can sense motion (i.e., velocity) in the atmosphere directed toward and away from the radar. Velocity data helps in assessing atmospheric wind fields, as well as severe weather velocity signatures from thunderstorms. The WSR-88D system contains various software algorithms as well that produce a number of other radar products and alarms when threshold values of certain parameters are met. The radar also can communicate with other WSR-88D systems via dial-up capabilities. The WSR-88D greatly enhances the ability of NWS forecasters to issue short-term forecasts for any weather situation, as well as timely and accurate warnings during severe thunderstorm events. Forecasters undergo in-depth training in order to become highly proficient with the radar and to properly interpret severe weather radar signatures. Data available from the WSR-88D allows NWS meteorologists to thoroughly dissect and evaluate thunderstorms and their trends, all of which are extremely helpful in the warning decision process. Accurate spotter reports also are critical to assist in the analysis process and to verify radar signatures. As technology advances, the ability of the radar is updated with new software algorithms.

 

 

Display of a classic tornado signature.
The Doppler image of the classic tornado signature with the clearly defined gate-to-gate red and green image display. Green shows wind direction flowing toward the radar, with red showing movement away. Gate-to-gate indicates rotation within the thunderstorm.

 

This is the old Jackson NWS 74-S radar which was replaced by the 88D. Requiring constant surveillance by an operator who manually interpreted and encoded the observation for transmission. This data was then plotted on a map which was re-transmitted to the field.

 

For additional information:

 

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