Wind shear is important for storm development
CEDAR RAPIDS, Iowa (KCRG) - You may have heard this term before and if you’re wondering what it means, then this article is for you! In short, there’s both directional wind shear and speed wind shear.
Speed shear is exactly how it sounds and when present, wind increases in speed as you go up in the atmosphere. Directional shear is when the wind changes direction as you go up in the atmosphere.
The speed shear is important as it allows the storm to have its updraft (fuel source basically) displaced from the downdraft. This allows for the storm to maintain strength or even strengthen some more rather than weaken. If this type of shear isn’t present, the storms will typically rain themselves out since the updraft and downdraft will be on top of each other.
The directional shear is important as it allows for the storm to have a rotating updraft, which could eventually lead to a tornado. It’s important to note that there are many factors that lead to tornadoes and simply having directional shear doesn’t mean it’s a slam dunk tornado situation. In fact, only about a quarter of all supercells will produce a tornado.
Strong storms prefer both directional and speed shear to not only develop, but maintain their strength. In nearly all severe storm cases, both directional and speed shear are present which is why strong wind shear is such a good indicator of severe weather potential.
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