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Old 07-31-2017, 11:09 AM
 
Location: Seymour TN
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My husband read a scientist's post somewhere that if you watch the total eclipse near fresh water, fog could form and possibly block the view of the sun. Temps are supposed to drop 5-10 degrees in places of totality, I guess. Did anyone here see the total eclipse in 1979 near a lake or river, and witness a lot of fog?
Thanks.
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Old 07-31-2017, 12:05 PM
 
Location: Somewhere in northern Alabama
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I live with a creek in my backyard. The "scientist" isn't thinking clearly.

It takes time for fog to develop. On average, even with a high dewpoint after rainstorms, I don't see traces developing much before midnight with the sun set around 8 PM. Fog won't develop until the dewpoint is reached. Say the dewpoint is 70 degrees (which is a normal high for it some midsummer days in the southeast) and the temperature prior to the eclipse is 90 degrees (also quite common late summer in the southeast). Before fog could even begin to develop, the temps would have to drop 20 degrees, and even as it started to develop, the heat wouldn't drop below dewpoint because of the immense amount of energy loss it takes for water vapor to condense. Only after a number of minutes would any meaningful fog develop.

What is FAR more likely is a weather front making the viewing of the eclipse impossible unless you get above the clouds.
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Old 08-01-2017, 04:37 AM
 
Location: Seymour TN
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Thanks Harry, I basically thought the same thing. I found the article on Forbes, Jack Straton was watching the eclipse on the Columbia River, and said
“I had a perfect view, up until 2 minutes before totality.” That's when Straton says the temperature dipped so suddenly, he missed the exact celestial moment he'd been waiting for: “Mist rose off the river, and entirely blocked the total eclipse,” he says.

You think it was just a fluke, very unlikely to happen again?
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Old 08-01-2017, 09:26 AM
 
Location: Somewhere in northern Alabama
15,412 posts, read 46,475,246 times
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I would say it was highly unlikely. IF the air was supersaturated (AT the dewpoint) to begin with and very still, it might happen, but it would be unusual in most areas of the country. I wonder if he was near a waterfall entering the river, or some sort of natural concentration - perhaps dense woods still wet from a recent rain? I can easily imagine the gorge holding excessive moisture, being as deep as it is, and parts of the PNW being a rainforest. Since cold air sinks and the gorge might not get sun until late, there likely was a well of cool dense (saturated) air that was right on the verge of condensing. I'm sure you have experienced such conditions, where even the slight movement of walking seems to coat you in moisture.

If you want to avoid something like that, make sure you aren't in an area that had fog (or cloud cover) that morning and check the relative humidity.

Now you have me wondering... the energy to dissipate fog or limit formation doesn't have to come from sensible heat. Helicopters are used to stir air over crops to prevent freezing, and loud or resonant noise can shock air to disrupt the condensation process. That could be an interesting experiment. Thanks for getting my brain cells to exercise.
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