When it comes to how to read weather radar and the basics — there aren’t a lot of different ways to approach it.
These products show how strong precipitation cores are by the ‘reflection’ back to the radar from a storm. Reflectivity products are some of the most common you’ll see anywhere, so it is best to get to know them.
There are two main types of reflectivity images you should know about.
Base Reflectivity: This scan allows you to see the level of returned energy to the radar, shown in decibels (dBZ). Typically, the higher the decibel level returned, the brighter the color. In most cases, the strongest storms will show values of red and pink on most applications.
Composite Reflectivity: This is a composite image of all the elevations of the radar. Radar scans both horizontally and vertically — so when you look at composite reflectivity, it is showing you both the returns at the lowest level nearer the surface and the ones further up in the storm — with the highest value shown on the radar chart.
It is also worth noting that radar shows what has happened and not what is happening. Radar images are delayed data, so you must always consider that the image you see is already old the second you see it.