Brilliant Halo Treats Sky Watchers Early Sunday

For those who were outside late Saturday evening November 24th into Sunday morning, a fairly brilliant lunar halo was visible across a large portion of the region.  A halo is similar to a rainbow, in that light is refracted, that is bent, at a certain angle from the light source. With a  rainbow, water droplets act as small prisms, separating out the individual colors which make up sunlight. A lunar halo forms via refraction of moonlight (which is reflected sunlight) by ice crystals in the upper level of the atmosphere. In the case of the halo late Saturday night into Sunday, the ice crystals were cirrostratus clouds in advance of an upper level wave moving out of Canada.

The appearance of a halo often indicates the approach of a rain or snow producing weather system. In this case, there is a weak system moving across southern Manitoba which may bring light snow to parts of the region.

Below is a picture of the lunar halo taken from the parking lot of the Grand Forks National Weather Service Office shortly after midnight, November 25th. Please note that while this photo only shows a portion of the halo, it completely encircled the moon.

Lunar Halo as viewed from NWS Parking lot early Sunday

More information on halos is available from many sources, including your local library as well as the United States Naval Observatory.

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