If you’ve been out today and looked up at the sky you’ve probably seen them: the contrails!
Clearly, since airplanes cause them they are more prevalent near the airports. Steve H. emailed me: Hi Frank, any idea what’s going on with all the vapor trails all over NW Houston this morning? and this from Larry: Hi Frank. I am 76 yrs old and have watched you since day one. You are our most accurate weather forecaster. Question, at 10 am on today Tuesday December 12th, there are MANY contrails crisscrossing our skies. What causes so many? Thanks!
I actually blogged about this four years ago.
In a nutshell: Airplane engines release an exhaust of water vapor, carbon dioxide, sulfur, carbon monoxide, and other particles, the only one of which matters to contrails is the water vapor. Right now, the air up there is around 10 degrees, plenty cold to turn that water vapor into ice crystals.
That’s exactly what you’re seeing, trails of ice crystals against a calm sky. If the humidity is high (and it is--86% at Hobby this morning with temperatures in the upper 40s) then the contrails will last a while, sometimes hours, where if the humidity is low then the dry air will cause the trails to evaporate pretty quickly.
My full blog from 2019 is RIGHT HERE which also addresses ChemTrails and Aliens! Have a look. In the meantime, enjoy that sky!
Frank
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