The grid displayed above is a Weather Event Impact Matrix. Bottom to top on the left side is the confidence (ranging from very low to high) while below the grid from left to right is the impact the possible event may have (also from very low to high). Each potential incoming event would be rated using those criteria. For example a high confidence in a low impact event (such as light to moderate rain) would be something to just be aware of – not need to get prepared for well in advance. On the other hand, a medium confidence in a high impact event (such as heavy rains or a tropical storm) would be something that getting prepared for would definitely be warranted. When there is a high confidence in a high impact event, its time to take action.