It gets very teknikologically complex Salty.
But if you can follow this...
A northerly wind blows from the north in a southerly direction so in that case the wind goes south. Other winds follow the same pattern

To be a trifle more serious.
I used to ponder on this one too. i learnt at an inland river beach only about 10 or so kms from the ocean (straight line). We would often get way less seabreeze there than what was coming in at the coast.
Had visions of a SWer pushing back a great wall of easterly moving air but that didnt make sense either.
One day I was driving to the coast from inland. The farm I was leaving from had a strong easterly blowing but Seabreeze was telling me it was 15 to 20 kts SW at Woodies. As i approached the coast there was clear dust line rising from the ground on the coast side & upwards at an angle of about 30 degs. It was then I realised that the wind doesnt come in as a wall pushing back it actually shears off and over against the opposing wind. Sure enough as soon as I reached the point near where the dust line left the ground there was the seabreeze - just as Lauries arrows had said it would be.
Mightnt solve your problem but I thought it was interesting ??