Have you ever noticed that some storms are shown on the local news weather radar as circular blotches and some are curved much like a crescent? The crescent or curved shape you see actually indicates a much stronger storm. That shape you see is what is referred to as the bow echo.
Bow Echo vs Circular Blotches
According the national weather service, a bow echo is the shape that larger storm systems take on during their development as the system spreads across different areas. The strongest part of storm is located on the leading edge of the bow echo. If you do not see a bow echo and only see circular blotches, these are much smaller, isolated storm systems that will not last long and will be significantly weaker.
Knowing what type of storm you are dealing with is very important in order to take the necessary safety precautions. If you can identify bow echoes, you’ll have a much better understanding of storms and how to be prepared for hazardous weather conditions.
How to Identify Bow Echoes
Identifying bow echoes on weather reports is critical for understanding the strength of a particular storm and being able to predict how long it will last. While small storms consist of cooled air that sinks and spreads along the surface of the earth until it dies, larger storms and storms that move across an area quickly are able to replenish their “reserve” of cool air, which allows them to maintain their strength.
As a storm moves across an area, its cool air sticks close to the ground, which pushes any warmer in the area above the storm. Because air cools as it rises, this once-warm air then contributes even more to the conditions that keep the storm strong. Because the warm air keeps the cool air low to the ground even as it rises, the cool air is forced to the sides as it moves along, which creates the bow shape that you can see on weather radar.
So, next time you see a crescent shape on the weather radar, you know that the storm is worth paying attention to.