G'day 172_Freighter
Firstly it pays to remember that if the earth didn't rotate, the wind would blow straight from an area of high pressure, into an area of low pressure, however because of the earth's rotation, the coriolis force acts on this airflow as it attempts to move from high to low pressure.
In a high pressure system, we have sinking air, which as it hits the surface has nowhere to go but away from the centre of the system. The coriolis force then acts on this air to produce a deflection to the left as seen in the diagram below (in the southern hemisphere).
The opposite occurs in a low pressure system. Air is rising therefore air is being sucked into the system at the surface. However once again due to coriolis force it takes a deflection to the left as it attempts to move over the surface of the earth. This is why we get clockwise or cyclonic flow (cyclonic simply meaning "as the earth rotates") around a low pressure system, and anti-clockwise or anti-cyclonic flow around a high pressure system as you can see from this diagram(once again in the southern hemisphere).
The other thing to be aware of is that the coriolis force is the strongest when the wind speed is highest, and zero when there is no wind.
Gradient wind is accepted by the met man to be above 3000 feet. From this height up the wind flow follows parallel to the isobars as you said. Below 3000 feet the wind speed is slowed down due to friction created by the surface of the earth, and we call this the surface wind. Now When we slow the wind speed down we reduce the coriolis force, and this no longer counters the pressure gradient force, so now the surface wind now deflects across the isobars in favour of the pressure gradient force. The amount by which this deflects depends upon the nature of the surface. So to answer your question, it is the surface wind (below 3000 feet) which is deflected to the right of the gradient wind (above 3000 feet) no matter whether in a high or low pressure system.
This degree of deflection is accepted to 30 degree's over land ( due to more friction over land therefore reducing the coriolis force) and 10 degrees over the sea due to less friction over ocean. The point to remember is that the surface wind is always deflected to the right of the gradient wind, or if you remember your backing and veering, the surface wind has veered with respect to the gradient wind. Bob might jump on later and tell a story about how hot air ballooning pilots can use this theory to somewhere control where their balloon will end up by adjusting their altitude to pick up the wind that they would prefer.
That would depend on if your ACTUALLY in the gradient wind or the surface wind
The surface wind is veering when compared to the gradient wind, or if you prefer, the gradient wind has backed compared to the surface wind. Does your head hurt yet? Mine does
The definitions for Gusts and Squalls unfortunately are not in the AIP, but as long as you have Bob's book you will have the definitions.
Good Luck.
