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il_rmk
02-25-2008, 04:32 AM
john,

Friday night near Wisconsin Rapids I drove into some very thick fog that was very strange. The temp was 5 degrees and all of the sudden we drove into a wall of zero visibility fog and the temp dropped 6 degrees, after slowing down to about zero we drove into a fog that seemed to be about 10 feet off the ground. My head lights were fine but right above the truck it was a ceiling of dense fog for about 4 miles. Visually it felt like I was driving through a tunnel with 8 feet of clearance. After we got through this the temp went back to 5 degrees. It was on a long open road with no water near just a long open road through cornfields. Thought maybe you would have some insight. Thanks and THINK SNOW

admin
02-25-2008, 12:42 PM
il_rmk-

This was what is called radiational fog. It is caused by the air cooling in the process of radiational cooling, or just due to the fact that the sun had set and there was no wind and the temps were allowed to cool.

In this case, the temps cooled to the dewpoint and the water vapor in the air condensed and formed fog. Because you can get different layers of air temp and moisture content to occur, you can get layers of fog to form.

-John