Final answer:
The National Weather Service Doppler radar network became operational in the 1990s, and it provides enhanced weather forecasting capabilities, including the detection of severe weather patterns.
Step-by-step explanation:
The National Weather Service Doppler radar network (WSR-88D) was made operational in the 1990s, specifically during the early part of the decade. Weather forecasters began experimenting with Doppler radar much earlier, in the 1960s. The advantage of using Doppler radar in weather forecasting is its ability to detect motion, which allows forecasters to see the rotation in thunderstorms indicative of severe weather, such as tornadoes. This radar technology is crucial in providing timely warnings and increasing the accuracy of weather forecasts.