The direction of circulation of an atmosphereic disturbance is determined by the radial direction of flow (in or out) and the coriolis effect.

Inward flow is defined as low pressure. Outward flow is high pressure. With these two terms defined you get only two possibles per hemisphere for rotation. In a southern hemisphere for a normal rotation object, the high pressure rotation is counterclockwise. It cant be the other way around with simple pressure driven flows.

If you want to see this for yourself, look up the derivation of the coriolis effect.