Sun Nov 29 18:17:16 PST 2009
Reporter: Myles Henderson
Halo Around The Moon
A ring around the moon... What is it? Does it have anything to do with the weather?
Sunday evening hull_j sent in this tweet to CBS19Weather... @cbs19weather We saw a halo around the moon tonight. Was this a meteorological phenomenon?
Good eye and great question hull_j. The short answer... Yes, it is a meteorological phenomenon. The long answer... The ring around the Moon is caused by the refraction of light from ice crystals in the upper atmosphere. The shape of the ice crystals results in a focusing of the light into a ring.
This "halo" falls into a unique aspect of meteorology called atmospheric optics. Personally, one of my favorite sub categories of meteorology. (besides severe weather, of course) The most common feature is a rainbow, refraction of sunlight from water droplets in the lower atmosphere. Others include, sundogs (moondogs), sun (or moon) pillars, and coronas (not the summertime beverage). Each of these features is created by a unique set up and structure of water droplets or ice crystals.
The ring around the moon also has some weather folklore attached to it. The saying goes "Ring around the moon, rain is soon" The moon halo sometimes indicates that rain or bad weather is in the short term forecast. In the case of Sunday night, it seems to be true... rain is in the forecast for Monday.
Thanks again for the tweet hull_j and for anyone else who as a weather question feel free to send us a tweet CBS19Weather or an email firstname.lastname@example.org.