GR2AE allows you to manually find the storm motion vector by marking a point on the radar display then going forward in time to the next radar scan and measuring the distance to that point. The speed is calculated based on radar time and distance.
The first step is to find a easy to identify location of a storm on the radar (such as a hook echo) and marking that point on the radar. Place the cursor over the point to be marked and right click on that point. Then select “Place Marker Here”
A small red dot will appear on the marked location. Now go forward in time at least one radar scan and right click on the location again and select “Storm Motion from Marker” (Be sure you have “Measure from Marker” checked otherwise you will have an incorrect measurement.)
You now have the storm motion vector plotted on the right bar
The storm motion vector is important when looking at storm relative velocity data and using the volume explorer. It also impacts some algorithms.
If you already know the storm motion vector you can enter it by pressing the storm motion vector button on the top control bar
Enter the azimuth and speed and press apply followed by OK