SUNDOG IN SHORT TERM

Answered at Oct 22, 2024

Understanding Sundogs: A Short-Term Weather Indicator

Sundogs, also known as parhelia, are fascinating atmospheric phenomena that appear as bright spots on either side of the sun. These optical wonders are not just beautiful to behold; they can also serve as short-term weather indicators. Let's explore how sundogs form and what they can tell us about upcoming weather conditions.

What Are Sundogs?

Sundogs are bright patches of light that appear 22 degrees to the left and right of the sun. They are part of a family of halos caused by the refraction of sunlight through ice crystals in the atmosphere. These ice crystals are typically found in high-altitude cirrus or cirrostratus clouds (source).

How Do Sundogs Form?

The formation of sundogs involves the refraction and scattering of sunlight by hexagonal ice crystals. These crystals act like prisms, bending the light rays and creating a spectrum of colors. The red hues are closest to the sun, while the colors gradually shift to blue as they move outward (source).

Sundogs as Weather Predictors

Sundogs can provide clues about upcoming weather conditions. Here's how:

  • Presence of Cirrus Clouds: Sundogs indicate the presence of cirrus clouds, which are high-altitude clouds made of ice crystals. These clouds often signal that a weather front is approaching, bringing changes in weather (source).

  • Precipitation Potential: When sundogs are visible, it suggests that the atmosphere contains moisture. As the ice crystals descend, they can increase the likelihood of precipitation within a day or two. Morning sundogs might indicate afternoon showers, while evening sundogs could suggest rain the following morning (source).

Optimal Viewing Conditions

To spot sundogs, look for these conditions:

  • Sun Position: Sundogs are most visible when the sun is low on the horizon, such as during dawn or dusk. This angle allows sunlight to pass through more of the atmosphere, increasing the chances of alignment with ice crystals (source).

  • Cirrus Clouds: Check for the presence of cirrus clouds, which contain the hexagonal ice crystals necessary for sundog formation. These clouds appear as wispy, featherlike streaks in the sky (source).

Historical and Cultural Significance

Throughout history, sundogs have been interpreted in various ways:

  • Ancient Greece: The Greeks associated sundogs with Helios, the sun god, believing they were his companions as he traveled across the sky (source).

  • Norse Legend: Vikings thought sundogs were reflections of sunlight off whale spouts, creating a dramatic image in the sky (source).

  • Native American Folklore: Some Native American tribes viewed sundogs as spirit guides offering wisdom and guidance, often seen as positive omens (source).

Conclusion

Sundogs are not only captivating optical phenomena but also serve as natural weather indicators. By understanding the conditions that lead to their formation, we can use sundogs to predict short-term weather changes. So, the next time you see these radiant spots beside the sun, take a moment to appreciate their beauty and the weather clues they provide.