Does momentum play a role in a storms direction.

[Guest]

Does a tropical cyclone prefer to stay in the same direction it is currently heading in, or does its current direction have no bearing on its future direction.

[x-y-no]

Does a tropical cyclone prefer to stay in the same direction it is currently heading in, or does its current direction have no bearing on its future direction.

Wow ... I should probably let one of the pro mets answer this one.

The short answer is no - not in the sense of a storm system being like a billiard ball rolling in a given direction and speed. OTOH, momentum has a lot to do with the dynamics of a system.

Jan

[kevin]

I have no idea how fluid dynamics work, so I also will let the pros handle this very good question. x-y-no is correct, a storm is not like a billiard ball which is self contained and works on a surface separate from itself.

[rainydaze]

Well, to make a long story short. A hurricane takes the path of least resistance. Like if you were to place a leaf in a river. It would flow along the current. The rocks in the river are like high pressures. A leaf cannot "go through" a rock. It goes around it. That is how a hurricane works. A high pressure is like a rock, the hurricane cannot travel through it. It will always go around it...hence the path of least resistance.
A leaf can have the momentum of the whole river, but it still cannot crash through a rock.
My very amateur answer... lol

[Wthrman13]

Does a tropical cyclone prefer to stay in the same direction it is currently heading in, or does its current direction have no bearing on its future direction.

TC's don't have momentum in the same sense, as say, a bowling ball has momentum. Statements like "No way that hurricane will slow down and turn north, it has too much momentum and will go on to hit Florida" are simply false. If the steering flow is such that if it were to change suddenly to a more northward motion from a more westward one, the hurricane would respond in kind, and wouldn't have any "leftover inertia", at least not in the same sense as a comparable sized solid object. (Don't laugh, I saw these type of statements many times when Floyd was approaching, and missed, Florida, in '99). This is because TC's are not solid or otherwise discrete masses, but instead are patterns (vortices to be specific) embedded in a fluid, namely the atmosphere. As such, their motion is governed by the fluid dynamics of vortices, which does not strictly translate from a simple momentum analog. A TC, more or less, will move with the mean flow of the fluid it is embedded in, sort of like a leaf in a stream, but with important differences. While a leaf's effect on the stream flow is negligible, the effect of a TC on the flow it is embedded in is not. That is, while the steering flow affects the TC, the TC's circulation also affects the steering flow. This kind of interaction is inherently nonlinear and depends on many factors, including the size and strength of the TC's circulation, which of course is always changing. There are also complex effects arising from the change in Coriolis force with latitude (called the Beta effect) that affect TC motion. But, to a first approximation, you can use the general steering flow to get a good idea of the TC's motion.

[coriolis]

That's a great explanation - I even understood it!