Prevailing Winds

I know Jason mentioned earlier that winds were mainly north-westerly. But I just went on BOM and it came up with below. This is for Tindal, a nearby town at 9am. Apparently south-easterly wind is stronger. Beat that Jason! though looking at both Tindal and Darwin's wind roses, I think its safe to assume that at 9am the winds will blow SE and in the afternoon onwards will go the opposite direction.
However it's very different at 3pm and much calmer.