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Ideas for Teaching

• Stereo photography
• Why radar can't (usually) see tornadoes
• Graphing information
• Vectors for wind speed
• Calculating %
• Simple math
• Not so simple math
• Wildflowers & rainfall

Vectors Help You Calculate Wind Speed

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Dust off those trigonometry functions!

At 22:21 and 51.25 seconds UTC on May 3, 1999, Probe 1 measured winds of 9.39 m/s at 154.2 degrees (0 is north). At that time the vehicle speed was 12.92 m/s at 90.10 degrees. What is the ambient wind?

The figure below can be used for additional data points. The main part of the graphic is greatly expanded from the inset image showing radar reflectivity of the storm. The small, black box in the inset is the area in the main body of the figure. Dots within the yellow boxes (left side) are in the rear flank downdraft of the storm. Dots in the light green colors are in the forward flank.

Full wind barbs are 10 m/s, half barbs are 5 m/s. Assume the cars are moving at 35 miles per hour to the north (line of dots extending vertically on the right side) or east (line of dots extending across the image just south of the tornado). In this case, the ambient wind is plotted. Calculate the measured wind.

Last updated: March 25, 2002
Created by: DSZ