sorry if its been a topic before, but why doesn't a seabreeze blow directly onshore?
and why does it come from the nor east on the east coast but the sou west in wa?
and when the **** are we going to get one in northern nsw?
A seabreeze can come directly on shore. However, depending on where you are in the world there will often be other weather patterns at work such as regular seasonal high and low pressure cell patterns. Without any seabreeze these high and low pressure areas may also cause wind that can be in a varity of directions. Combine these winds from more regional weather patterns with a somewhat local costal seabreeze and the result will generally be cross-shore or longshore wind.
Additionally, as the seabreeze is caused by near surface temperatures over land and sea (...but also at altitude), and the land or sea temperature can vary up or down the coast, then the greatest land sea temperature difference may not be directly perpendicular to the coast. And so in theory the seabreeze may be more cross shore.
The coriolis effect is generally only seen on very large scales, such as high and low pressure weather patterns, and via those systems would probably have more influence on more local sea breezes. Yet its a chicken and egg problem to some degree...
HI Stamp.
To answer your questions, the set up for a sea breeze starts in the morning as soon as the sun starts to heat up the land. Once the land temp rises it heats up the air immediately above it. This air then rises and moved up and out over the sea, which is now colder than the air and cools it down again. This air then tries to move back over the land and is heated up again. However, in the southern hemisphere coriolis effect bend the movement of air to the left, so instead of the air moving directly back to the land it bends to the left. The easiest way to understand coriolis effect is to imagine you are on a roundabout, and in the southern hemisphere it is going clockwise as viewed from the top. The same as viewing earth from space looking at the south pole. Now if you were to throw a ball from close to the center of the roundabout to someone further from the center, as the ball left your hand it would travel in a straight line, but because someone further out has more velocity it would appear to you, to travel in an arc bending to the left and would miss the person you were throwing the ball at. The same would happen if you were both at the edge of the roundabout but on different quadrants. As the ball left your hand it would appear to bend to the left, where as it is really travelling in a straight line.
What happens to the air is that when it tries to move to the warmer land it is constantly being bent off course until it is travelling at right angles to the way it is trying to go. Not sure if Ive explained this very well, its hard without diagrams but if you draw it out, this may help.
The second part of your question should be easier to grasp.
If we ignore fronts for the time being, we have low pressures formed over all the large land masses in the world and high pressures formed over the oceans. These high pressures try to move towards the low pressures, but because of our friend corollas, the air end up moving round the high pressures moving to the left and in an anticlockwise direction. So Australian has a thermal low which form over the interior and a high in the Pacific and a high in the Indian ocean. Look at the direction the air will move as 3 cogs meshed together, and then add to that local sea breeze effects.
NSW will probably get some descent sea breezes when NSW stops being so flooded and the land heats up. I believe this is also an el nino year which is a warm body of water in the Pacific, this would also make sea breezes weaker and muck up the trade winds formed by the Pacific high,and generally change the whole balance of the weather, probably why you have flooding in the first place.
Hope this helps
