posted by Mike on .
Posted a couple of days ago on this subject.
The wind blows anti-clockwise round a depression (N Hemisphere). In a stereotypical depression isobars form fairly regular circles round the centre of the depression with kinks at the warm and cold fronts with the isobars in the warm sector generally straight.
Generally the most prevalent forces are the pressure gradient and the Coriolis Effect. I understand the kinks at the fronts are due to thermal disturbances along the fronts (Warm & Cold air mixing) but fail to understand why the isobars in the warm sector are straight. The warm sector seems to be oblivious to the forces acting on the rest of the depression!
I am sure someone can help me in this matter.
maybe think along the lines that the warm fronts are more energy and are more prone to move in the direction that the force of the energy is moving. where as the cloder fronts have less energy and can be easierly influenced by the surrounding invironment. ie. sun, landscape, warm front.
Sorry Spenser this has not helped.
In case I did not make the question clear.
Why are the isobars straight in the warm sector of a depression?
I think this is because the undercutting of the less dense warm sector air by the relatively more dense cold sector air, induces a small vertical component to the warm sector air mass. This modifies the surface isobar pattern, and, I believe is also accelerates the velocity of the cold front, cf that of the warm front.