The barrel gases were escaping the muzzle at 1000 fps in the direction of "down Elm St.". The wind was a minor factor compared to that.
When 3 shots are fired from the TSBD into-the-wind from a height of 6 stories, and a gunpowder odor is smelled all the way down Elm St close to the Triple Underpass, in addition to being smelled at the Railroad Overpass which extends across the Stemmons Fwy On-Ramp, that gunpowder odor is Not emanating from the TSBD.