BELHYDROMET

On September 20, residents of Zhlobin witnessed a picturesque atmospheric phenomenon — a rainbow crown appeared around the Sun in the sky over the city. This is not just a beautiful sight: for meteorologists, such a crown is also a kind of natural barometer that allows short-term weather forecasts to be made.

So what is a rainbow crown? It is an optical phenomenon that occurs due to the diffraction of light in small water droplets contained in clouds. Most often, a crown forms on thin altocumulus or cirrocumulus clouds. The mechanism of its appearance is quite elegant: a light wave bends around a droplet, and rays of different colors (that is, different wavelengths) are deflected at different angles. As a result, a rainbow halo appears right next to the solar disk. In this case, a bluish ring forms closer to the Sun, and a reddish one forms at the outer edge.

The diameter of the crown directly depends on the size of the water droplets in the cloud: the smaller the droplets, the larger and wider the rainbow ring will be. Thus, the very change in the size of the crown already carries important information about the state of the atmosphere.

Observations show that the behavior of the crown can indicate upcoming weather changes:

If the crown begins to shrink in size, this is a sign that the water droplets in the clouds are growing larger and becoming heavier. This usually portends a thickening of cloud cover and precipitation — rain or snow, depending on the season.
If the crown expands or becomes less bright, it means that the droplets in the clouds are evaporating and decreasing. This sign indicates that the sky will soon clear and the weather will improve.
It was precisely this dynamic that was recorded in Zhlobin. Natalya Marchenko, head of the Zhlobin weather station of the Gomeloblhydromet Branch, during her shift was conducting standard observations of the state of the sky and captured this striking phenomenon in a photo. The crown was a series of concentric rings smoothly transitioning from whitish and bluish shades inside to a reddish-orange edge outside. At first it was quite wide and bright, but then it gradually began to shrink. Within a few hours, the sky became overcast with lower and denser clouds, and by evening it was almost completely covered by cloud cover.

Thus, a rainbow crown is not only a rare and mesmerizing sight, but also a clear example of how nature gives us clues about upcoming weather changes.

Belhydromet specialists continue to closely monitor such atmospheric phenomena, combining modern observation methods with centuries-tested signs to make forecasts even more accurate and timely.

Based on materials from the website of the Gomeloblhydromet Branch