Vertical wind shear is the second critical factor in the determination of thunderstorm type and potential storm severity. Vertical shear, or the change of winds with height, interacts dynamically with thunderstorms to either enhance or diminish vertical draft strengths.
Photograph by: Moller
Looking north from about 15 miles, we see a storm embedded in strong vertical shear. Upper level winds near cloud summit were blowing from west to east (left to right) at 130 MPH. Surface winds were from the south at 20 MPH, indicating over 100 MPH of shear through the cloud layer! Such vertical shear often destroys all but the strongest storms by literally blowing the updraft away from its base.