This book was written to understand the complexities of southern Appalachian weather. Gaffin has worked for the National Weather Service in Morristown, TN and has a lot of insights to understanding the complex weather systems that affect this region.
The southern Appalachian includes some of the oldest mountains in the world and is in the cross-hairs of two major sources of moisture: the Gulf of Mexico and the Atlantic Ocean.
Gaffin divides the region into four distinct areas: Cumberland Plateau (1500 to 3000 ft.); the Great Tennessee Valley (500 to 1500 ft.); southern Appalachian Mountains (1500 to 6500 ft.); and the Blue Ridge Mountains located on the eastern edge of the studied area. The unique topography combined with the moisture sources creates a lot of interesting weather scenarios.
Here are some of those weather situations:
- mountains act as a heating source through solar radiation
- temperature inversions (air cooling faster near the surface than above it) causing mountainous areas to be warmer than the valley. This happens especially with a strong southwest wind that traps cold air in the valley.
- urban heat islands affecting the low morning temperatures in outlying areas despite little difference in elevation
- for every 1000 feet in elevation difference, there is usually a 3.5 degree change in Fahrenheit temperature
- valley trapping of cold air creates situations for dense fog
- mountain heat waves create strong wind gusts.