Sun dogs

Brown Swiss · Nov 3, 2015

Anyone else see them in the sky yesterday evening, about 4 o'clock central time? I thought you could only see them when it was really cold out, guess there were ice crystals in the air! I'm in sw wi, if that helps.

Bill(Wis) · Nov 3, 2015

Cirrus clouds are composed of ice crystals and what are called "sun dogs" is the reflection of sunlight off from those ice crystals. Cirrus clouds are up around 20000 feet above the surface and it's always freezing up there. In fact, for example, when Yuma Arizona has a ground temperature of 120-130 degrees F, the freezing level there will be around 13000 feet. Cirrus clouds, in many cases, are a precursor to incoming weather systems and the sun dogs are assumed by many to be a signal of changing weather. Usually within 24-48 hours.

Mike(NEOhio) · Nov 3, 2015

I've been seeing a lot of them this year. Late September thru October on chilly afternoons. The arcs are always 23 degs. from the Sun.

JRSutton · Nov 3, 2015

actually I'd say quite a bit colder than 'freezing' at 20,000 feet. I know you were just generalizing, but I got curious and had to look it up, I think the average temperature at 20,000 feet is about 12 below zero.

Bill(Wis) · Nov 4, 2015

Yes. If I'd only thought to put "below" in front of "freezing" everything would have been OK. I don't really know what the maximum record altitude of the freezing level might be but it would be below 20000 feet for sure. During WWII (The Big One), bomber crews were issued sheepskin lined clothing for that very reason. The late Col Phillip (Flip) Cochran told the story on the Johnny Carson show about always making sure the B29s had a case of beer on board on their maintenance check flights which went to high altitude to cool it down.

Sun dogs

Brown Swiss

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Bill(Wis)

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Mike(NEOhio)

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JRSutton

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Bill(Wis)

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