The National Weather Service has a series of local weather radars that help predict the weather. Radar is a device that sends a signal out to a "target." In the case of weather radar, the target is a patch of precipitation. The signal is then returned and collected by antenna. Once the data is collected, it is interpreted to gain an understanding of weather conditions.
Almost every state in the United States has their own local weather radars, except the smaller ones like the New England states, which all share a series of weather radars. Puerto Rico and Guam also have their own Local Weather Radars. Some local areas have a higher concentration of weather radars. For example, there are at least 12 radars on the East Coast. Since a lot of storms come to land from the Atlantic Ocean, these radars are present to help detect and predict the storms.
There are so many different types of weather patterns than can occur in the United States. Some parts see a lot of hurricanes. There are often violent thunderstorms throughout the country. Hurricanes are also possible, as is flooding. Local weather radars do their best to detect these patterns and storm systems. The more data that is collected from them, the more accurately future weather conditions can be predicted. In order to predict the future, you often have to understand the past.
From the date that is received by the local weather radars, experts can come up with a local weather report. You can find such weather reports in multiple places online or listen to the report on your radio or television. Just keep in mind that even though it is a science and there are many experts who spend their lives studying the weather, nature has a way of changing its mind at the last minute.