There was an upper low to the NW of Adelaide, so steering flow for the storm was NE-SW and pretty weak hence it moved slowly. Weather usually comes from west etc but it isn't definite. Will always go the direction that steering flow is, usually 10,00ft or so. The storms on friday developed on the hills as they do in that type of setup and moved slowly SW. Very cold air up high so hail was no surprise. Was fine elsewhere. Thats just typical storms for you. Tho if the whole of the rest of Adelaide looked out their window, they would have seen a ring of storms from the Mid North, down the ranges and also some over YP moving away. Storms died at sunset as the heating from sun was lost. Ive got a pic of the storm from a distance:
Back on topic, great win by SA really toughed it out, undermanned against a quality outfit.