There's nothing I love more than taking pictures out an airplane window. It's an awesome experience for a weather geek to finally be up in the sky with the weather he or she tracks. But on my flight into Atlanta this past Monday, I was up in the sky and the weather was down on the ground. About an hour after sunrise, I noticed a thick layer of fog on parts of the South Fork Catawba River west of Charlotte, NC., while the rest of the ground was perfectly clear. Why did that happen?
The answer comes down to the effects of a microclimate.
According to weather observations at the nearby Charlotte-Douglas International Airport, the low the morning of Monday March 10 was 32 degrees. Since it was a perfectly sunny day with practically no wind, the atmosphere was able to warm up very quickly that morning.
Water retains heat more easily than land, so it stays warmer during the night and cooler during the day. Fog forms when the temperature falls to the dew point (making the humidity 100%) and the water vapor condenses into a cloud.
On this sunny morning, the land heated up much faster than the water, so temperatures on land were able to quickly rise above the dew point. The air above the water on the South Fork Catawba River, however, didn't heat up nearly as fast, so temperatures immediately above the river stayed even with the dew point. This allowed a very narrow bank of fog to form on parts of the river.
It was a pretty cool meteorological phenomenon to witness.
Here are some more pictures I took: