What is your "wind direction" arrow based on?
The wind is not really strong but there are gusts. These gusts can be seen here:
1. Muchmore film shows wind blowing clothing:
2. Flags on President's limo catch gusts from time to time and point straight back.
3. Blue scarf on lady standing on north side of Elm seen just to left (east) of Stemmons sign in zfilm appears to keep moving to left side.