Frank Parker wrote:
Take a look at my HWO posting of yesterday showing runways 10 R and L as active. The wind is from 060 and the little arrow appears to be drawn at 130 degrees, which is NOT the wind relative to an aircraft on the active runway. I am sure there is some meaning to it, but to me it is totally illogical. Brian, can you jump in here and explain what the intent of the little arrow is?
Frank, let me walk you through this.
First, note the wind barb in the left pane. I am going to add a blue dotted line showing the wind direction, and show how that wind barb and the little arrow you're asking about are exactly the same thing.
Fig 1: See red circle, below, with blue line added to represent the 060 wind as depicted by the wind barb. Note also the silhouette of a plane lined up to land on runway 10R.
Fig 2: I moved the blue line down a bit so that it actually intersects the 10/28 runways, for clarity.
Fig 3: Now, take what's shown in the left pane, and rotate it as if you're changing from "north up" to "track up" mode on the moving map (with the plane at the bottom of the screen moving "up" along the page). This is an industry standard way of representing "forward flight" on a flat display. For this example for 10R, it would be a 100-deg counterclockwise rotation. (For 01L or 01R, it would be a 10 deg counterclockwise rotation, etc.)
Fig 4: What the diagram looks like after rotation:
Fig 5: Let's focus in on just the plane getting ready to land on runway 10R, and how the wind is blowing across that runway:
Fig 6: Now let's look at how Brian is indicating the wind as it is blowing across runway 10R:
So: Which part of that is not logical?