If you’ve looked outside at dusk in recent days, you were likely treated to some fairly spectacular sunsets thanks to a series of fast-moving, low-pressure “clipper” systems that have moved through the area at just the right time.
“We have been kind of lucky to get those high, upper cirrus clouds to break between the horizon so we can get the refraction of the sunlight off the cool moisture in the air,” said Brian Leatherwood, a meteorologist at the Chicago office of the National Weather Service. “And these clipper systems carry a lot of moisture.”
Monday evening’s sunset was one of the best yet, sending professional and amateur photographers scrambling to document the pink, orange, red and yellow hues mixing with the darkening skies.
Leatherwood said that while some systems provide a better opportunity for a photogenic sunset, predicting whether the cloud cover will break over the horizon is almost impossible.
“That’s really difficult,” he said. “It’s just luck.”
Clipper systems are standard winter weather bringing strong winds and colder temperatures out of southwestern Canada and across the Great Lakes region of the United States.
The cloud cover scatters the wavelengths of the sunlight, and the moisture in the air refracts and reflects it in different shades than the traditional blue skies we’re used to. The same thing can happen at sunrise, too, meteorologists said.
In the summertime, high-pressure systems carrying dust and other particles, perhaps from wildfires, combined with high cloud ceilings caused a similar effect, Leatherwood said.