Why do some thunderstorm winds spread out in all directions while others do not?

there have been days when a thunderstorm would move in from the southwest. the winds would go calm, and then as the gust front ped through the winds picked up out of the southwest, and of course got stronger in the storm and the core. on the backside the winds shifted to the northeast but not as strong. Other times the winds blow from the southwest throughout the whole storm. what causes these factors to happen?