HTropical Cyclones and High Pressure Systems

[sprinklerman]

I understand how and why a tropical cyclone travels around a high pressure system. My question is the relationship between the outer edges of the high and the center of the cyclone. In other words if the high pressure edge (and how do you define high pressure) is at point A, (point A not actually being a point but the border of the high pressure) and center of the cyclone is at point B, how far away do the two points stay away from each other? Is it based on the relationship between relative strengths? Or do they actually "touch" as the center foollows the edge?
Hope the queston makes sense.
Thanks!

[x-y-no]

Well ... even though you'll see us talking about storms "bumping up against" a ridge or "moving around the end" of a ridge, this is really a misnomer. Think of highs a hills of air, troughs as valleys between those hills, and low pressure systems as hollows. They can (theoretically) get arbitrarily close, but the closer they get the sharper the slope becomes, and the more energy that takes to maintain.

The real dynamics is a lot more complicated, because air is moving around all the time - flowing into a tropical system at the surface and out again in the upper layers, and then eventually sinking down again as it moves away - so a tropical system can actually strengthen an adjacent ridge.

Jan

[weatherwindow]

in general, the outermost isobars of the two systems are in proximity. the direction of the flow at that boundary determines the direction of movement of the cyclone. the area of high pressure is, by far, the dominant circulation, both in area and impact........rich

[sprinklerman]

Thanks! Then I guess the different strength and weakness of each system determines when a storm turns at a certain longitude or lattitude.

[timeflow]

As a tropical system is moved along by that flow between the outermost isobars of each system, (which is kind of the point where the pressures agree, right?) it's visually like a small gear spinning against a larger gear. (I wonder how the similarity is in terms of the actual dynamics.) My question is why the L tends to stick along the periphery of the H, so that it would curve north. Is it simply channeled this way along the outermost isobars? Is there an attractive force between the H and L that is simultaneously repelled?

[x-y-no]

As a tropical system is moved along by that flow between the outermost isobars of each system, (which is kind of the point where the pressures agree, right?) it's visually like a small gear spinning against a larger gear. (I wonder how the similarity is in terms of the actual dynamics.) My question is why the L tends to stick along the periphery of the H, so that it would curve north. Is it simply channeled this way along the outermost isobars? Is there an attractive force between the H and L that is simultaneously repelled?

Absent any other steering, a tropical cyclone in the northern hemisphere will move to the northwest due to something called the"beta effect" - which is a result of the change in strength of the coriolis force with latitude.

Jan