METEOROLOGIST JEFF HABY
1. What is SRDS?
Storm Relative Directional Shear (SRDS) is the directional change of wind that effects a storm between the
surface and 3 kilometers.
2. How is SRDS determined?
First, the storm speed and direction of movement is approximated. Next, the wind direction effecting the base
of the storm is found. Then, the wind direction effecting the 3 kilometer level of the storm is found. Lastly,
the amount of degree difference between the two directions is found. For example, a south wind effecting
the base of a storm (180 degrees) and a west wind effecting the storm 3 kilometers up (270 degrees) results
in a SRDS of 270 - 180 = 90 degrees. The sounding at the bottom has a SRDS of 68 degrees.
3. Operational significance of SRDS:
|less than 30 ||Weak||30-59 ||Some
Tornadoes: Strong SRDS is important to produce a storm environment favorable for tornadoes. A low level turning
of wind generates
WAA: A strong
veering wind is associated with Warm Air Advection (WAA).
a. Mesoscale influences can vary SRDS significantly.