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Are Skew-Ts the source for the data on the EZWxBrief EZRoute Profile?

Updated: Oct 9, 2021


In a single word...NO! It seems quite common to hear pilots try to incorrectly compare a vertical route profile with a Skew-T log (p) Diagram. It's as they believe the Skew-T log (p) is some kind of primary source of data. For example, here's a common comment that shows a deep misunderstanding of the differences between the two when referring to a specific application's vertical route profile.


"I thought they used soundings as their base engine, but I guess not. I'd rather everything be based off of soundings."


There's a lot to unpack here. First, "soundings" are generated from two separate data sources. The first source is radiosonde data. Radiosondes (weather balloons) are launched twice daily at 11Z and 23Z throughout the world. The data collected from each radiosonde launch includes temperature, humidity (dewpoint), pressure and wind (speed and direction). The resulting data is called a radiosonde observation or RAOB. This data can be plotted as a function of altitude (pressure) on a thermodynamic diagram called a Skew-T log (p) Diagram. These are only available at locations where the radiosondes are launched as shown below.