Significant shear is observed when the temperature difference across the front is 5 C -LRB- 9 F -RRB- or more , and the front moves at 30 knots or faster .
Change in wind can be 90 degrees in direction and 40 kt in speed .
Change in wind can be 90 degrees in direction and 40 kt in speed .
Simplificar: Significant shear is observed when the temperature difference across the front is 5 C -LRB- 9 F -RRB- or more , and the front moves at 30 knots or faster . Producción: