Satellite imagery shows the high-altitude, cirrus clouds of ice crystals over New England Saturday.
This afternoon, we received a spectacular photograph of a halo around the sun, taken by Brad Mahoney in West Harwich, MA, via the “Send to Us” section of our Noyes’ 1DegreeOutside Weather app. The sky above Southern New England is adorned with a deck of high-altitude, thin cirrus clouds, creating the perfect conditions for this beautiful phenomenon. But what exactly is a sun halo, and why does it form?
A halo around the sun, formally known as a 22-degree halo, is a ring of light that encircles the sun. This optical phenomenon is not only visually stunning but also fascinating from a meteorological perspective.
The halo is caused by the refraction, reflection, and dispersion of light through ice crystals suspended in high-altitude cirrus or cirrostratus clouds. These clouds are composed of tiny hexagonal ice crystals that bend the light passing through them at a 22-degree angle, resulting in the formation of a halo.
The specific conditions required for a sun halo to form include:
When sunlight enters one side of an ice crystal and exits through another, the change in speed and direction (refraction) causes the light to bend. Because ice crystals are typically hexagonal, they bend the light at consistent angles, resulting in the formation of a perfect circle. The halo is always seen at an angle of 22 degrees from the sun, hence the name “22-degree halo.”
Sun halos are relatively rare, making them a special sight when they do occur. They often indicate the presence of high-altitude cirrus clouds, which can sometimes be a precursor to changes in the weather, such as an approaching warm front. In Saturday’s case, they are running ahead of an approaching jet stream disturbance that will deliver isolated showers and downpours to Southern New England during Saturday evening and night. Capturing a sun halo in a photograph is a delightful reminder of the beauty and complexity of our atmosphere. As you admire the stunning image from West Harwich, MA, take a moment to appreciate the intricate interplay of sunlight and ice crystals that created this mesmerizing ring around the sun.
For continuous updates and detailed weather forecasts, visit 1DegreeOutside.com or use the Noyes’ 1DegreeOutside Weather mobile app – including the ability to send us photos and reports, just like Brad did to inspire this post!
