Was Mother Nature working on her driving test?
It was an image that came to mind when I saw this time lapse video of the skies over Seattle on Saturday, March 7.
The video, taken from a camera atop the University of Washington Atmospheric Sciences Building, faces west and shows a raging Puget Sound Convergence Zone, where winds colliding from the north and south battled throughout the day. The cloud layers were lurching forward, then into reverse, and forward again -- sort of like a car trying to parallel park -- as the winds pushed north and south in an atmospheric tug of war battle.
The zone is caused when winds off the coast split around the Olympic Mountains - -some go to the north through the Strait of Juan de Fuca then south toward Seattle, while other air goes around the southern side of the mountains and turns north toward Seattle.
Where they collide is often quite the show, as the air is forced upward where it cools and condenses into clouds and rain, or snow, or both.
We featured some video of a different Convergence Zone on March 9th, but I think now that I've seen it, the 7th's is even a better visual example of how a Convergence Zone works.
And here that same day's video from Silverdale, courtesy of Dr. Dale Ireland.