two-thirds stem height point and above the cloud-top height point
for the prediction being prepared. If wind vectors between the two-
thirds stem height point and the cloud-top height point fall outside
the radial lines drawn from ground zero through these points, expand
the angle formed by these two radial lines to include these outside
Step 5. Determination of the Effective Wind Speed.
Measure the length of the radial line, in kilometers, from GZ to the
Record this value on line k of the
cloud-bottom height point.
worksheet. Read the time of fall from the cloud bottom (determined
in Step 3), from the worksheet (Figure 3-3, item j). Compute the
effective wind speed as shown below and record on line 1 of the