Most of us have heard the old adage, “Red sky in morning, sailor’s warning.” There is actually truth behind the saying.
When storms approach from the west they spread clouds across the sky, well in advance of their precipitation and wind. Often, a fair weather system (high pressure) is moving away, to the east, at the same time that a storm approaches. When the light from the rising sun in the eastern sky shines through the clear sky of a departing high pressure system, it illuminates the underside of the approaching storm clouds.
The sunrise colors of red and yellow are produced because the light at sunrise spans a greater distance through atmosphere than when the sun is directly overhead, at midday. The light at sunrise is filtered and scattered by dust particles and moisture in the air, which in turn produces the beautiful color that we see in the sky. This same process also happens at sunset.
To explain and illustrate the weather setup for a ”red sky in morning” sunrise, I analyzed past colorful sunrise photos with satellite imagery taken the same day. What I found was a predictable and repeatable type of weather pattern that is responsible for creating vibrant color in the sky at sunrise. As expected, the weather pattern involves storms and fronts approaching from the west and clear sky to the east.
Results are explained below with colorful sunrise photos and satellite images.
A large area of clear sky to our east, over the coastline and western Atlantic Ocean, is one of the key weather ingredients necessary to produce a colorful sunrise for Washington. The other key ingredients are clouds moving across the sky at the time of sunrise.
Broken cloud cover will produce interesting patterns of color in the sky. Solid cloud cover will produce a sheet of vivid color across a large portion of the eastern sky. But, as I mentioned, there needs to be clear sky to the east so the rising sun can illuminate the clouds with light.
Studying weather satellite imagery during the night or pre-dawn hours will help you spot the necessary weather ingredients coming together that will produce a beautiful sunrise. I often use the Unisys Weather website. Look for the position of the clouds relative to the areas of clear sky where you will be viewing. Check out the various satellite images above to recognize the weather patterns that have produced past colorful sunrises.
Be forewarned, however, sometimes the clouds of an approaching storm or front will move in quicker than anticipated and you’ll end up watching a gray sunrise. I’ve done that several times and it’s not fun. It’s just the risk of trying to chase the perfect sunrise.
Larger versions of the sunrise photos, and more sunrise photos, can be found here.