The answer to this is:
A. is a measurement of how well a forecast is predicting actual values.
I have seen this type of tracking signal before, they use this for news forecast to track severe weather such as tornadoes, severe weather, hot weather, winter storms and even hurricanes. This helps the people know what the weather will be like in the next few days or so, so they can get prepared for any storms or hot weather.
it's a interesting technology they have.
Hope this helped :)
Have a great day
