When you’ve defined a proposed route in WeatherSpork you may notice that it picks a number of “close” fly-by stations (airports) to include along that route. These show up on the Map view as rounded square icons like those shown below. But how far is KMSV off of your great circle route from KBOS to KCLE to KORD? That’s known as cross track distance (abbrevated XTK) and is defined as the closest distance from the station to the route as shown below.
Now in WeatherSpork version 4.3.0 we’ve added a cross track distance (abbreviated XTK) to the route progress strip at the bottom of the Route Profile view. These fly-by stations along with those defining your route (departure, midpoints and destination) will be added to this view. This gives you a quick indication of just how far this station is off of the route. For example, in the Profile view below, KMSV is 27 nm from the route identified in the blue oval. To decrease clutter in the route progress strip, cross track distances are not shown for the departure, destination and midpoint stations as shown by the red Xs below; it’s assumed that the cross track is 0 nm.
Keep in mind that the weather can be quite different at these fly-by stations as compared to stations right over the actual route. The greater the distance, the more likely the variation in weather. Keep that big weather picture in mind.
“Most pilots are weatherwise, but some are otherwise.”
Weather Systems Engineer