Front Speed

[Old Dominion Flyer]

The FAA publication Aviation Weather states "Cold fronts move at about the speed of the wind component perpendicular to the front just above the frictional layer."

My first thought was: frontal speed = (perpendicular wind component) x .5

How does one determine the perpendicular wind component? I'm having difficulty locating any other sources that explain this topic.

 

[casey]

How does one determine the perpendicular wind component?

cosine

And im not sure where your 0.5 factor is coming from. The winds above the frictional layer will be stronger than the surface winds usually (due to less friction). Use the 850mb winds as a first guess.

 

[Old Dominion Flyer]

not sure where your 0.5 factor is coming from

You're right. I was thinking about warm fronts, as they travel at half the speed. Thanks for pointing that out.