Autumn weather is as changeable as a teenager's moods. On Sunday night a heavy bank of clouds rolled in just as the Harvest Moon began to peek over the eastern horizon. The low pressure system parked over our heads and remained in place for two days, bringing two inches of much-needed rain.

Wednesday dawned fresh and golden. By early afternoon warmer air had caused unusual cloud formations to build up. Altoculumulus undulatus clouds are named for their resemblance to rippling wave trains along

the surface of the water. Also known as billows, these clouds form as the result of wind shear. Localized differences in wind speed and direction break up larger altocumulus clouds, reshaping them as narrow cloud-rolls. Billows may be ramrod-straight or form gentle curves, but are always evenly spaced in parallel rows.

I recall seeing billow clouds a few times in my childhood. Back then I found their symmetrical design a little frightening, reminiscent of the ribs of some skeletal sky-giant. As an adult I observe natural phenomena through the rational lens of science. Yet plenty of youthful imagination still tinges my view. Standing in the yard my eye was drawn to the straight line of those clouds, and for a moment I imagined having the ability to fly along that sky-path. But even as I watched, the clouds began to lose their structure—joining then stretching, thinning and breaking apart. Within 20 minutes, the sky was completely clear and blue. And I remained affixed to the ground.

Tentative sunlight at the terminus of the week brought local maple trees to the peak of color. While our neighbors began to spend evening hours raking, trees in our meadow and yard have steadfastly held on to their leaves. A golden glow fills the air at all hours, seeping through the windows and reaching my office as I work. As if I needed another distraction!

But this too shall pass. As I write this in the late hours of Friday night, the drying leaves of a pin oak outside my office window begin to rattle. The wind has picked up from the west. With it, capricious Autumn may bring the first snow of the season.

Announced by all the trumpets of the sky,
Arrives the snow
—Ralph Waldo Emerson, from "The Snowstorm"