This is a computer forecast of wind in knots at 250 mb (around 35,000 feet) for tomorrow at 1 PM EST. Wind speeds are shaded every 20 knots starting at 50 knots. The color shading can be used to show where the jetstream is (the area of maximum wind). The shaft of the wind has a small dot at the end. The wind blows along the shaft toward the dot. The wind barbs which come out at right angles to the shaft show the wind speed. Each full barb is 10 knots, each half barb is 5 knots, each flag is 50 knots. 10 knots equals about 11.5 mph.